Big-Data-HPC-Platform/system/jlib/jfile.cpp

/*##############################################################################

    Copyright (C) 2011 HPCC Systems.

    All rights reserved. This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
############################################################################## */


#ifdef _WIN32
#define _WIN32_WINNT 0x0500  // for CreateHardLink
#include <errno.h>
//#include <winsock.h>  // for TransmitFile
#endif

#include "platform.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <algorithm>

#if defined (__linux__)
#include <time.h>
#include <dirent.h>
#include <utime.h>


#include <sys/vfs.h>
#include <sys/mman.h>
#include <sys/sendfile.h>
#endif

#include "time.h"

#include "jerror.hpp"
#include "jlib.hpp"
#include "jio.hpp"
#include "jmisc.hpp"
#include "jsort.hpp"

#include "jmutex.hpp"
#include "jfile.hpp"
#include "jfile.ipp"

#include <limits.h>
#include "jexcept.hpp"
#include "jsocket.hpp"      // for IpAddress
#include "jregexp.hpp"
#include "portlist.h"


// #define REMOTE_DISCONNECT_ON_DESTRUCTOR  // enable to disconnect on IFile destructor
                                            // this should not be enabled in WindowRemoteDirectory used

#ifdef _DEBUG
#define ASSERTEX(e) assertex(e); 
#else
#define ASSERTEX(e)
#endif


#ifdef __64BIT__
#define DEFAULT_STREAM_BUFFER_SIZE 0x100000
#else
#define DEFAULT_STREAM_BUFFER_SIZE 0x10000
#endif

#ifdef _WIN32
#define NULLFILE INVALID_HANDLE_VALUE
#else
#define NULLFILE -1
#endif

static IFile *createIFileByHook(const RemoteFilename & filename);

static char ShareChar='$';

bool isShareChar(char c)
{
    return (c==ShareChar)||(c=='$');
}

char getShareChar()
{
    return ShareChar;
}

void setShareChar(char c)
{
    ShareChar = c;
}

StringBuffer &setPathDrive(StringBuffer &filename,unsigned drvnum)
{
    return swapPathDrive(filename,(unsigned)-1,drvnum);
}


unsigned getPathDrive(const char *s)
{
    char c = *s;
    if (isPathSepChar(c)&&(s[1]==c)) {
        s = strchr(s+2,c);
        if (!s)
            return 0;
    }
    if (isPathSepChar(c))
        s++;
    if (*s&&((s[1]==':')||(isShareChar(s[1]))))
        return *s-'c';
    return 0;
}

StringBuffer &swapPathDrive(StringBuffer &filename,unsigned fromdrvnum,unsigned todrvnum,const char *frommask,const char *tomask)
{
    const char *s = filename.str();
    char c = *s;
    if (isPathSepChar(c)&&(s[1]==c)) {
        s = strchr(s+2,c);
        if (!s)
            return filename;
    }
    if (isPathSepChar(c))
        s++;
    if (*s&&((fromdrvnum==(unsigned)-1)||(*s==(fromdrvnum+'c')))&&((s[1]==':')||(isShareChar(s[1])))) 
        filename.setCharAt((size32_t)(s-filename.str()),todrvnum+'c');
    else if (frommask&&*frommask) { // OSS
        StringBuffer tmp;
        if (replaceConfigurationDirectoryEntry(filename.str(),frommask,tomask, tmp))
            tmp.swapWith(filename);
    }
    return filename;
}


bool checkFileExists(const char * filename)
{
#ifdef _WIN32
    for (unsigned i=0;i<10;i++) {
        DWORD ret = (DWORD)GetFileAttributes(filename); 
        if (ret!=(DWORD)-1)
            return true;
        DWORD err = GetLastError();
        if (err!=ERROR_IO_PENDING)
            break;
        Sleep(100*i);
    }
    return false;
#else
    struct stat info;
    return (stat(filename, &info) == 0);
#endif
}

bool checkDirExists(const char * filename)
{
#ifdef _WIN32
    DWORD attr = GetFileAttributes(filename);
    return (attr != (DWORD)-1)&&(attr & FILE_ATTRIBUTE_DIRECTORY);
#else
    struct stat info;
    if (stat(filename, &info) != 0)
        return false;
    return S_ISDIR(info.st_mode);
#endif
}

static void set_inherit(HANDLE handle, bool inherit)
{
#ifndef _WIN32
    long flag = fcntl(handle, F_GETFD);
    if(inherit)
        flag &= ~FD_CLOEXEC;
    else
        flag |= FD_CLOEXEC;
    fcntl(handle, F_SETFD, flag);
#endif
}

static StringBuffer &getLocalOrRemoteName(StringBuffer &name,const RemoteFilename & filename)
{
    if (filename.isLocal()&&!filename.isNull()) {
        filename.getLocalPath(name);
#ifdef _WIN32
        // kludge to allow local linux paths on windows
        const char *n=name.str();
        if (n[0]=='/') {
            StringBuffer tmp;
            if (isShareChar(n[2])) {
                tmp.append(n[1]).append(':');
                n+=3;
            }
            while (*n) {
                if (*n=='/')
                    tmp.append('\\');
                else
                    tmp.append(*n);
                n++;
            }
            name.clear().append(tmp);
        }
#endif
    }
    else  
        filename.getRemotePath(name);
    return name;
}


CFile::CFile(const char * _filename)
{
    filename.set(_filename);
    flags = ((unsigned)IFSHread)|((S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)<<16);
}

void CFile::setCreateFlags(unsigned cflags)
{
    flags |= (cflags<<16);
}

void CFile::setShareMode(IFSHmode shmode)
{
    flags &= ~(IFSHfull|IFSHread);
    flags |= (unsigned)(shmode&(IFSHfull|IFSHread));
}


bool CFile::exists()
{
    if (stdIoHandle(filename)>=0)
        return true;
    return checkFileExists(filename);
}

#ifdef _WIN32

bool WindowsCreateDirectory(const char * path)
{
    unsigned retry = 0;
    loop {
        if (CreateDirectory(path, NULL))
            return true;
        DWORD err = GetLastError();
        if ((err==ERROR_FILE_NOT_FOUND) || (err==ERROR_PATH_NOT_FOUND) || (err==ERROR_FILE_EXISTS) || (err==ERROR_CANNOT_MAKE))
            break;
        else if (err==ERROR_ALREADY_EXISTS) {
            DWORD attr = GetFileAttributes(path);
            if ((attr != -1)&&( attr & FILE_ATTRIBUTE_DIRECTORY))
                return true;
            return false;
        }
        if ((retry++==10)||  // some or all of the following can occur when the domain controller gets busy
                             // retrying improves chance of success
            ((err!=ERROR_NETNAME_DELETED)&&(err!=ERROR_DEV_NOT_EXIST)&&(err!=ERROR_GEN_FAILURE)&&(err!=ERROR_NETWORK_BUSY)&&(err!=ERROR_BAD_NET_NAME))) 
            throw MakeOsException(err,"WindowsCreateDirectory %s", path);
        //PROGLOG("Retrying(%d) WindowsCreateDirectory %s, err=%d",retry,filename,err);
        Sleep(retry*100); 
    }
    return false;
}

#else


bool LinuxCreateDirectory(const char * path)
{
    if (!path)
        return false;
    if (CreateDirectory(path, NULL))
        return true;
    else
    {
        if (EEXIST == errno)
        {
            struct stat info;
            if (stat(path, &info) != 0)
                return false;
            return S_ISDIR(info.st_mode);
        }
    }
    return false;
}


#endif


bool localCreateDirectory(const char *name)
{
    if (!name)
        return false;
    size32_t l = (size32_t)strlen(name);
    if (l==0)
        return true;
    if (isPathSepChar(name[0])&&((l==1)||(isPathSepChar(name[1])&&!containsPathSepChar(name+2))))
        return true;
#ifdef _WIN32
    if (name[1]==':') {
        if ((l==2)||((l==3)&&isPathSepChar(name[2])))
            return true;
    }
#endif
    if (checkDirExists(name))
        return true;
#ifdef _WIN32
    if (WindowsCreateDirectory(name))
#else
    if (LinuxCreateDirectory(name))
#endif
        return true;
    if (isPathSepChar(name[l-1])) l--;
    while (l&&!isPathSepChar(name[l-1]))
        l--;
    if (l<=1)
        return true;
    StringAttr parent(name,l-1);
    if (!localCreateDirectory(parent.get()))
        return false;
#ifdef _WIN32
    return (WindowsCreateDirectory(name));
#else
    return (LinuxCreateDirectory(name));
#endif
}




bool CFile::createDirectory()
{
    return localCreateDirectory(filename);
}



#ifdef _WIN32
union TimeIntegerUnion
{
    FILETIME        ft;
    ULARGE_INTEGER  l;
};

void FILETIMEtoIDateTime(CDateTime * target, const FILETIME & ft)
{
    if (target)
    {
        TimeIntegerUnion u;
        memcpy(&u, &ft, sizeof(ft));
        unsigned __int64 hundredNanoseconds = (u.l.QuadPart % 10000000);
        u.l.QuadPart -= hundredNanoseconds;
        SYSTEMTIME systime;
        FileTimeToSystemTime(&u.ft, &systime);
        target->set(systime.wYear, systime.wMonth, systime.wDay, systime.wHour, systime.wMinute, systime.wSecond, (unsigned)(hundredNanoseconds*100));
    }
}

FILETIME * IDateTimetoFILETIME(FILETIME & ft, const CDateTime * dt)
{
    if (!dt)
        return NULL;

    SYSTEMTIME systime;
    TimeIntegerUnion u;
    unsigned wYear, wMonth, wDay, wHour, wMinute, wSecond, nanoSeconds;
    dt->getDate(wYear, wMonth, wDay);
    dt->getTime(wHour, wMinute, wSecond, nanoSeconds);
    systime.wYear = wYear;
    systime.wMonth = wMonth;
    systime.wDay = wDay;
    systime.wHour = wHour;
    systime.wMinute = wMinute;
    systime.wSecond = wSecond;
    systime.wMilliseconds = 0;
    SystemTimeToFileTime(&systime, &u.ft);
    //Adjust the fractions of a second ourselves because the function above is only accurate to milli seconds.
    u.l.QuadPart += (nanoSeconds / 100);
    memcpy(&ft, &u, sizeof(ft));
    return &ft;
}

#endif


bool CFile::getTime(CDateTime * createTime, CDateTime * modifiedTime, CDateTime * accessedTime)
{
#ifdef _WIN32
    //MORE could use GetFileAttributesEx() if we were allowed...
    FILETIME timeCreated, timeModified, timeAccessed;
    HANDLE handle = CreateFile(filename, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
    if (handle==(HANDLE)-1)
        return false;
    GetFileTime(handle, &timeCreated, &timeAccessed, &timeModified);
    CloseHandle(handle);
    FILETIMEtoIDateTime(createTime, timeCreated);
    FILETIMEtoIDateTime(modifiedTime, timeModified);
    FILETIMEtoIDateTime(accessedTime, timeAccessed);
#else
    struct stat info;
    if (stat(filename, &info) != 0)
        return false;
    timetToIDateTime(accessedTime,  info.st_atime);
    timetToIDateTime(createTime,    info.st_ctime);
    timetToIDateTime(modifiedTime,  info.st_mtime);
#endif
    return true;
}

bool CFile::setTime(const CDateTime * createTime, const CDateTime * modifiedTime, const CDateTime * accessedTime)
{
#ifdef _WIN32
    FILETIME timeCreated, timeModified, timeAccessed;
    FILETIME *pTimeCreated, *pTimeModified, *pTimeAccessed;

    pTimeCreated = IDateTimetoFILETIME(timeCreated, createTime);
    pTimeModified = IDateTimetoFILETIME(timeModified, modifiedTime);
    pTimeAccessed = IDateTimetoFILETIME(timeAccessed, accessedTime);
    HANDLE handle = CreateFile(filename, GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
    if (!handle)
        return false;
    SetFileTime(handle, pTimeCreated, pTimeAccessed, pTimeModified);
    CloseHandle(handle);
    return true;

#elif defined (__linux__)

    struct utimbuf am;
    if (!accessedTime||!modifiedTime) {
        struct stat info;
        if (stat(filename, &info) != 0)
            return false;
        am.actime = info.st_atime;
        am.modtime = info.st_mtime;
    }
    if (accessedTime)
        am.actime   = timetFromIDateTime (accessedTime);
    if (modifiedTime)
        am.modtime  = timetFromIDateTime (modifiedTime);
    return (utime(filename, &am)==0);
#else
    UNIMPLEMENTED;
#endif
}



fileBool CFile::isDirectory()
{
#ifdef _WIN32
    DWORD attr = GetFileAttributes(filename);
    if (attr == -1)
        return notFound;
    return ( attr & FILE_ATTRIBUTE_DIRECTORY) ? foundYes : foundNo;
#else
    struct stat info;
    if (stat(filename, &info) != 0)
        return notFound;
    return S_ISDIR(info.st_mode) ? foundYes : foundNo;
#endif
}

fileBool CFile::isFile()
{
    if (stdIoHandle(filename)>=0)
        return foundYes;
#ifdef _WIN32
    DWORD attr = GetFileAttributes(filename);
    if (attr == -1)
        return notFound;
    return ( attr & FILE_ATTRIBUTE_DIRECTORY) ? foundNo : foundYes;
#else
    struct stat info;
    if (stat(filename, &info) != 0)
        return notFound;
    return S_ISREG(info.st_mode) ? foundYes : foundNo;
#endif
}

fileBool CFile::isReadOnly()
{
#ifdef _WIN32
    DWORD attr = GetFileAttributes(filename);
    if (attr == -1)
        return notFound;
    return ( attr & FILE_ATTRIBUTE_READONLY) ? foundYes : foundNo;
#else
    struct stat info;
    if (stat(filename, &info) != 0)
        return notFound;
    //MORE: I think this is correct, but someone with better unix knowledge should check!
    return (info.st_mode & (S_IWUSR|S_IWGRP|S_IWOTH)) ? foundNo : foundYes;
#endif
}

#ifndef _WIN32

static bool setShareLock(int fd,IFSHmode share)
{
    struct flock fl;
    do {
        memset(&fl,0,sizeof(fl));
        if (share==IFSHnone)
            fl.l_type = F_WRLCK;
        else if (share==IFSHread)
            fl.l_type = F_RDLCK;
        else
            fl.l_type = F_UNLCK;
        fl.l_whence = SEEK_SET;
        fl.l_pid    = getpid(); 
        if (fcntl(fd, F_SETLK, &fl) != -1)
            return true;
    } while (errno==EINTR);
    if ((errno!=EAGAIN)&&(errno!=EACCES))
        ERRLOG("setShareLock failure %d, mode %d", errno,(int)share);
    return (share==IFSHfull); // always return true for full
}


#endif

HANDLE CFile::openHandle(IFOmode mode, IFSHmode sharemode, bool async, int stdh)
{
    HANDLE handle = NULLFILE;
#ifdef _WIN32
    if (stdh>=0) {
        DWORD mode;
        switch (stdh) {
        case 0: mode = STD_INPUT_HANDLE; break;
        case 1: mode = STD_OUTPUT_HANDLE; break;
        case 2: mode = STD_ERROR_HANDLE; break;
        default:
            return handle;
        }
        DuplicateHandle(GetCurrentProcess(), GetStdHandle(mode), GetCurrentProcess(), &handle , 0, FALSE, DUPLICATE_SAME_ACCESS);
        return handle;
    }

    DWORD share = 0;
    switch (sharemode) {
    case (IFSHfull|IFSHread):
    case IFSHfull:
        share |= FILE_SHARE_WRITE; 
        // fall through
    case IFSHread:
        share |= FILE_SHARE_READ;
    }
    DWORD fflags = async?FILE_FLAG_OVERLAPPED:0;
    if (async&&(mode==IFOread))
        fflags |= FILE_FLAG_SEQUENTIAL_SCAN; 
    switch (mode) {
    case IFOcreate:
        handle = CreateFile(filename, GENERIC_WRITE, share, NULL, CREATE_ALWAYS, fflags, NULL);
        break;
    case IFOread:
        handle = CreateFile(filename, GENERIC_READ, share, NULL, OPEN_EXISTING, fflags, NULL);
        break;
    case IFOwrite:
        handle = CreateFile(filename, GENERIC_WRITE, share, NULL, OPEN_ALWAYS, fflags, NULL);
        break;
    case IFOcreaterw:
        handle = CreateFile(filename, GENERIC_WRITE|GENERIC_READ, share, NULL, CREATE_ALWAYS, fflags, NULL);
        break;
    case IFOreadwrite:
        handle = CreateFile(filename, GENERIC_WRITE|GENERIC_READ, share, NULL, OPEN_ALWAYS, fflags, NULL);
        break;
    }
    if (handle == NULLFILE)
    {   
        DWORD err = GetLastError();
        if ((IFOread!=mode) || ((err!=ERROR_FILE_NOT_FOUND) && (err!=ERROR_PATH_NOT_FOUND)))
            throw MakeOsException(err,"CFile::open %s (%x, %x)", filename.get(), mode, share);
        return NULLFILE;
    }
#else
    if (stdh>=0)
        return (HANDLE)dup(stdh);

    unsigned fileflags = (flags>>16) &  (S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IWGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH);
    unsigned openflags;
    switch (mode) {
    case IFOcreate:
        openflags = O_WRONLY | O_CREAT | O_TRUNC;
        break;
    case IFOread:
        openflags = O_RDONLY;
        break;
    case IFOwrite:
        openflags = O_WRONLY | O_CREAT;
        break;
    case IFOcreaterw:
        openflags = O_RDWR | O_CREAT | O_TRUNC;
        break;
    case IFOreadwrite:
        openflags = O_RDWR | O_CREAT;
        break;
    default:
        return NULLFILE;
    }
    handle = _lopen(filename.get(), openflags, fileflags);
    if (handle == -1)
    {
        if ((IFOread!=mode) || (errno != ENOENT))
            throw MakeErrnoException(errno, "CFile::open %s", filename.get());
        return NULLFILE;
    }
    // check not a directory (compatible with windows)

    struct stat info;
    if (fstat(handle, &info) == -1) {
        int err = errno;
        close(handle);
        handle = NULLFILE;
        throw MakeErrnoException(err, "CFile::open fstat %s", filename.get());
    }
    if (S_ISDIR(info.st_mode)) {
        close(handle);
        handle = NULLFILE;
        throw MakeErrnoException(EISDIR, "CFile::open %s", filename.get());
    }
    
#endif
    return handle;
}

IFileIO * CFile::open(IFOmode mode)
{
    // we may want mode dependant defaults later 
    return openShared(mode,(IFSHmode)(flags&(IFSHfull|IFSHread)));
}


IFileAsyncIO * CFile::openAsync(IFOmode mode)
{
    HANDLE handle = openHandle(mode,IFSHread,true);     // I don't think we want shared write to an async file
#ifndef _WIN32
    set_inherit(handle, false);
#endif
    return new CFileAsyncIO(handle,IFSHread);
}

const char * CFile::queryFilename()
{
    return filename;
}


bool CFile::remove()
{
#ifdef _WIN32
    unsigned retry = 0;
    loop {
        if (isDirectory()==foundYes) {
            if (RemoveDirectory(filename) != 0)
                return true;
        }
        else {
            if (DeleteFile(filename) != 0)
                return true;
        }
        DWORD err = GetLastError();
        if ( (err==ERROR_FILE_NOT_FOUND) || (err==ERROR_PATH_NOT_FOUND) )
            break;
        if ((retry++==10)||  // some or all of the following can occur when the domain controller gets busy
                             // retrying improves chance of success
            ((err!=ERROR_NETNAME_DELETED)&&(err!=ERROR_DEV_NOT_EXIST)&&(err!=ERROR_GEN_FAILURE)&&(err!=ERROR_NETWORK_BUSY)&&(err!=ERROR_BAD_NET_NAME))) 
            throw MakeOsException(err,"CFile::remove %s", filename.get());
        //PROGLOG("Retrying(%d) DeleteFile %s, err=%d",retry,filename,err);
        Sleep(retry*100); 
    }
    return false;
#else
    if (isDirectory()==foundYes) {
        if (rmdir(filename) == 0)
            return true;
    }
    else {
        if (unlink(filename) == 0)
            return true;
    }
    if (ENOENT!=errno)
        throw MakeErrnoException("CFile::remove %s", filename.get());
    return false;
#endif
}

void CFile::rename(const char *newname)
{
    // now hopefully newname is just file tail 
    // however we do allow full paths and extract tail, warning if the directory appears to mismatch 
    StringBuffer path;
    splitDirTail(filename,path);
    StringBuffer newdir;
    const char *tail = splitDirTail(newname,newdir);
    if (path.length()&&newdir.length()) {
        if (strcmp(newdir.str(),path.str())!=0) 
            WARNLOG("CFile::rename '%s' to '%s' : directory mismatch",filename.get(),newname);
    }
    const char *dst = path.append(tail);
    if (isPathSepChar(dst[0])&&(dst[1]==dst[0])) { // hmm is share - convert to local path
        RemoteFilename rfn;
        rfn.setRemotePath(dst);
        if (rfn.isLocal())
            dst = rfn.getLocalPath(path.clear()).str();
    }
    if (-1 == ::rename(filename, dst)) 
        throw MakeErrnoException("CFile::rename(%s, %s)", filename.get(),dst);
    filename.set(path);
}

void CFile::move(const char *newname)
{
    if (!newname||!*newname)
        return;
    StringBuffer path;
    if (isPathSepChar(newname[0])&&(newname[1]==newname[0])) { // hmm is share - convert to local path
        RemoteFilename rfn;
        rfn.setRemotePath(newname);
        if (rfn.isLocal())
            newname = rfn.getLocalPath(path.clear()).str();
    }
#ifdef _WIN32
    unsigned retry = 0;
    loop {
        if (MoveFileEx(filename.get(),newname,0)) 
            return;
        DWORD err = GetLastError();
        if ((retry++==10)||  // some or all of the following can occur when the domain controller gets busy
                             // retrying improves chance of success
            ((err!=ERROR_NETNAME_DELETED)&&(err!=ERROR_DEV_NOT_EXIST)&&(err!=ERROR_GEN_FAILURE)&&(err!=ERROR_NETWORK_BUSY)&&(err!=ERROR_BAD_NET_NAME))) 
            throw MakeOsException(err,"CFile::move(%s, %s)", filename.get(), newname);
        Sleep(retry*100); 
    }
#else
    int ret=::rename(filename.get(),newname);
    if (ret==-1)
        throw MakeErrnoException("CFile::move(%s, %s)", filename.get(), newname);
#endif
    filename.set(newname);
}

#ifdef _WIN32
DWORD CALLBACK fastCopyProgressRoutine(
  LARGE_INTEGER TotalFileSize,          
  LARGE_INTEGER TotalBytesTransferred,  
  LARGE_INTEGER StreamSize,             
  LARGE_INTEGER StreamBytesTransferred, 
  DWORD dwStreamNumber,                 
  DWORD dwCallbackReason,               
  HANDLE hSourceFile,                  
  HANDLE hDestinationFile,              
  LPVOID lpData                        
)
{
    if (TotalBytesTransferred.QuadPart<=TotalFileSize.QuadPart)
    {
        CFPmode status = ((ICopyFileProgress *)lpData)->onProgress(TotalBytesTransferred.QuadPart,TotalFileSize.QuadPart);
        switch (status)
        {
        case CFPcontinue:
            return PROGRESS_CONTINUE;
        case CFPstop:
            return PROGRESS_STOP;
        default:
            return PROGRESS_CANCEL;
        }
    }
    return PROGRESS_CONTINUE;
}
#endif

bool CFile::fastCopyFile(CFile &target, size32_t buffersize, ICopyFileProgress *progress)
{
    // only currently supported for windows
#ifdef _WIN32
    unsigned retry = 0;
    loop {
        BOOL cancel=FALSE;
        if (CopyFileEx(queryFilename(),target.queryFilename(),progress?fastCopyProgressRoutine:NULL,progress?progress:NULL,&cancel,0))
            break;
        DWORD err = GetLastError();
        if ( (err==ERROR_FILE_NOT_FOUND) || (err==ERROR_PATH_NOT_FOUND) )
            return false;
        if ((retry++==10)||  // some or all of the following can occur when the domain controller gets busy
                             // retrying improves chance of success
            ((err!=ERROR_NETNAME_DELETED)&&(err!=ERROR_DEV_NOT_EXIST)&&(err!=ERROR_GEN_FAILURE)&&(err!=ERROR_NETWORK_BUSY)&&(err!=ERROR_BAD_NET_NAME))) 
            return false;
        Sleep(retry*100); 
    }
    return true;
#else
    return false;
#endif
}


void CFile::copySection(const RemoteFilename &dest, offset_t toOfs, offset_t fromOfs, offset_t size, ICopyFileProgress *progress)
{
    // check to see if src and target are remote


    Owned<IFile> target = createIFile(dest);
    const size32_t buffersize = 0x100000;
    IFOmode omode = IFOwrite;
    if (toOfs==(offset_t)-1) {
        if (fromOfs==0) {
            copyFile(target,this,buffersize,progress);
            return;
        }
        omode = IFOcreate;
        toOfs = 0;
    }
    OwnedIFileIO targetIO = target->open(IFOwrite);
    if (!targetIO)
        throw MakeStringException(-1, "copyFile: target path '%s' could not be created", target->queryFilename());
    MemoryAttr mb;
    void * buffer = mb.allocate(buffersize);
    OwnedIFileIO sourceIO = open(IFOread);
    if (!sourceIO)
        throw MakeStringException(-1, "copySection: source '%s' not found", queryFilename());
    
    offset_t offset = 0;
    offset_t total;
    try
    {
        total = sourceIO->size();
        if (total<fromOfs)
            total = 0;
        else
            total -= fromOfs;
        if (total>size)
            total = size;
        while (offset<total)
        {
            size32_t got = sourceIO->read(fromOfs+offset, (buffersize>total-offset)?((size32_t)(total-offset)):buffersize, buffer);
            if (got == 0)
                break;
            targetIO->write(offset+toOfs, got, buffer);
            offset += got;
            if (progress && progress->onProgress(offset, total) != CFPcontinue)
                break;
        }
    }
    catch (IException *e)
    {
        StringBuffer s;
        s.append("copyFile target=").append(target->queryFilename()).append(" source=").append(queryFilename()).append("; read/write failure").append(": ");
        e->errorMessage(s);
        IException *e2 = MakeOsException(e->errorCode(), "%s", s.str());
        e->Release();
        throw e2;
    }
}

void CFile::copyTo(IFile *dest, size32_t buffersize, ICopyFileProgress *progress,bool usetmp)
{
    doCopyFile(dest,this,buffersize,progress,NULL,usetmp);
}



void CFile::setReadOnly(bool ro)
{
#ifdef _WIN32
    if (!SetFileAttributes(filename, ro ? FILE_ATTRIBUTE_READONLY : FILE_ATTRIBUTE_NORMAL))
    {
        DWORD err = GetLastError();
        if ( (err!=ERROR_FILE_NOT_FOUND) && (err!=ERROR_PATH_NOT_FOUND) )
            throw MakeOsException(err, "CFile::setReadOnly %s", filename.get());
    }
#else
    struct stat info;
    if (stat(filename, &info) != 0)
        throw MakeErrnoException("CFile::setReadOnly() %s", filename.get());
    // not sure correct but consistant with isReadOnly
    if (ro)
        info.st_mode &= ~(S_IWUSR|S_IWGRP|S_IWOTH);
    else
        info.st_mode |= (S_IWUSR|S_IWGRP|S_IWOTH);
    chmod(filename, info.st_mode);
#endif
}


offset_t CFile::size()
{
    if (stdIoHandle(filename)>=0)
        return 0;   // dummy value
#ifdef _WIN32
    WIN32_FILE_ATTRIBUTE_DATA info;
    if (GetFileAttributesEx(filename, GetFileExInfoStandard, &info) != 0) {
        LARGE_INTEGER x;
        x.LowPart = info.nFileSizeLow;
        x.HighPart = info.nFileSizeHigh;
        return (offset_t)x.QuadPart;
    }
#else
    struct stat info;
    if (stat(filename, &info) == 0)
        return info.st_size;
#endif
#if 0
    // we could try opening but I don't think needed
    Owned<IFileIO>io = openShared(IFOread,IFSHfull);
    if (io)
        return io->size();
#endif
    return (offset_t)-1;
}

bool CFile::setCompression(bool set)
{
#ifdef _WIN32
    DWORD attr=::GetFileAttributes(filename.get());
    if(attr==-1)
        throw MakeOsException(::GetLastError(), "CFile::setCompression %s", filename.get());
    if (((attr & FILE_ATTRIBUTE_COMPRESSED) != 0) == set)
        return true;

    HANDLE handle=::CreateFile(filename.get(),GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,FILE_FLAG_BACKUP_SEMANTICS,NULL);
    if(handle==INVALID_HANDLE_VALUE)
        throw MakeOsException(::GetLastError(), "CFile::setCompression %s", filename.get());

    USHORT compression=set ? COMPRESSION_FORMAT_DEFAULT : COMPRESSION_FORMAT_NONE;
    DWORD bytes;
    if(::DeviceIoControl(handle, FSCTL_SET_COMPRESSION, &compression, sizeof(compression), NULL, 0, &bytes, NULL))
    {
        ::CloseHandle(handle);
        return true;
    }
    DWORD err=::GetLastError();
    ::CloseHandle(handle);
    throw MakeOsException(err, "CFile::setCompression %s", filename.get());
#else
    return false;
#endif
}

offset_t CFile::compressedSize()
{
#ifdef _WIN32
    DWORD hi, lo=::GetCompressedFileSize(filename.get(),&hi), err;
    if(lo==INVALID_FILE_SIZE && (err=::GetLastError())!=NO_ERROR)
    {
        if ( (err!=ERROR_FILE_NOT_FOUND) && (err!=ERROR_PATH_NOT_FOUND) )
            throw MakeOsException(err,"CFile::compressedSize %s", filename.get());
        return -1;
    }
    return makeint64(hi,lo);
#else
    return size();
#endif
}

class CDiscretionaryFileLock: public CInterface, implements IDiscretionaryLock
{
    bool locked;
    bool excllock;
    Linked<IFile> file;
    Linked<IFileIO> fileio;
    HANDLE handle;


public:
    CDiscretionaryFileLock(IFile *_file)
        : file(_file)
    {
        excllock = false;
        locked = false;
#ifdef _WIN32
        handle=::CreateFile(file->queryFilename(),GENERIC_READ,FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE,NULL,OPEN_EXISTING,FILE_FLAG_BACKUP_SEMANTICS,NULL);
        if(handle==INVALID_HANDLE_VALUE) {
            handle = NULLFILE;
            throw MakeOsException(GetLastError(),"CDiscretionaryFileLock::openhandle %s", file->queryFilename());
        }
#else
        handle = _lopen(file->queryFilename(), O_RDONLY, 0);
        if (handle == -1) {
            handle = NULLFILE;
            throw MakeErrnoException(errno, "CDiscretionaryFileLock::openhandle %s",file->queryFilename());
        }
#endif
    }
    CDiscretionaryFileLock(IFileIO *_fileio)
        : fileio(_fileio)
    {
        excllock = false;
        locked = false;
        handle = NULLFILE;
        CFileIO *cfileio = QUERYINTERFACE(_fileio,CFileIO);
        if (cfileio)
            handle = cfileio->queryHandle();
        if (handle==NULLFILE)
            throw MakeStringException(-1,"CDiscretionaryFileLock - invalid parameter"); 
    }
    ~CDiscretionaryFileLock()
    {
        if (locked)
            unlock();
        if ((handle!=NULLFILE)&&!fileio.get())
#ifdef _WIN32
            CloseHandle(handle);
#else
            _lclose(handle);
#endif
    }
    IMPLEMENT_IINTERFACE;

    virtual bool isLocked() { return (handle!=NULLFILE); }
    virtual bool isExclusiveLocked() { return excllock; }

    bool lock(bool exclusive=true, unsigned timeout=INFINITE)
    {
        if (locked) {
            if (exclusive) {
                if (excllock)
                    return true;
                unlock(); // have to unlock - unfortunate as means no window-less change mode
            }
            else {
                if (!excllock)
                    return true;
                unlock(); // have to unlock - unfortunate as means no window-less change mode
            }
        }
        unsigned interval = 1;
        unsigned start = msTick();
        loop {
#ifdef _WIN32
            OVERLAPPED overlapped;
            memset(&overlapped,0,sizeof(overlapped));
            if (LockFileEx(handle,
                (exclusive?LOCKFILE_EXCLUSIVE_LOCK:0)|((timeout==INFINITE)?0:LOCKFILE_FAIL_IMMEDIATELY),
                          0,1,0,&overlapped))
                break;
            
            DWORD err = ::GetLastError();
            if (err!=ERROR_LOCK_VIOLATION) 
                throw MakeOsException(err, "CDiscretionaryFileLock::lock");
#else
            if (setShareLock(handle,exclusive?IFSHnone:IFSHread))
                break;
#endif

            unsigned now = msTick();
            if (now-start>=timeout) 
                return false; 
            if (interval>timeout-now+start)
                interval = timeout-now+start;
            Sleep(interval);
            interval *= 2;
            if (interval>1000)
                interval = 1000;
        }
        excllock = exclusive;
        locked = true;
        return true;
    }

    void unlock()
    {
        if (handle!=NULLFILE) {
#ifdef _WIN32
            OVERLAPPED overlapped;
            memset(&overlapped,0,sizeof(overlapped));
            if (!UnlockFileEx(handle,0,1,0,&overlapped)) 
                throw MakeOsException(::GetLastError(), "CDiscretionaryFileLock::unlockhandle");
#else
            setShareLock(handle,IFSHfull);
#endif
        }
    }


};

IDiscretionaryLock *createDiscretionaryLock(IFile *file)
{
    return new CDiscretionaryFileLock(file);
}

IDiscretionaryLock *createDiscretionaryLock(IFileIO *fileio)
{
    return new CDiscretionaryFileLock(fileio);
}


unsigned CFile::getCRC()
{
    if (stdIoHandle(filename)>=0)
        return 0;   // dummy value
    unsigned crc=~0;
    MemoryAttr ma;
    void *buf = ma.allocate(0x10000);
    Owned<IFileIO> fileio = open(IFOread);
    if (fileio) {
        offset_t pos=0;
        loop {
            size32_t rd = fileio->read(pos,0x10000,buf);
            if (!rd)
                break;
            crc=crc32((const char *)buf,rd,crc);
            pos += rd;
        }
    }
    return ~crc;
}



//---------------------------------------------------------------------------

static Linked<IPasswordProvider> passwordProvider;

MODULE_INIT(INIT_PRIORITY_JFILE)
{
    return true;
}

MODULE_EXIT()
{
    passwordProvider.clear();
}

static bool parseShare(const char *filename,IpAddress &machine,StringBuffer &share)
{ // windows share parsing
    if (!filename||!isPathSepChar(filename[0])||(filename[0]!=filename[1]))
        return false;
    const char *start = filename+2;
    const char * end = start;
    while (*end && !isPathSepChar(*end))
        end++;
    if (!*end)
        return false;
    StringBuffer ipText(end-start, start);
    machine.ipset(ipText.str());
    end++;  
    while (*end && !isPathSepChar(*end))
        end++;
    start = filename;
    while (start!=end) {
        if (*start=='/')
            share.append('\\');
        else 
            share.append(*start);
        start++;
    }
    return true;

}

static CriticalSection connectcrit;

static bool connectToExternalDrive(const char * const filename)
{
    CriticalBlock block(connectcrit);
    if (!passwordProvider)
        return false;
#ifdef _WIN32

    StringBuffer share, username, password;
    IpAddress ip;
    if (!parseShare(filename,ip,share))
        return false;
    if (!passwordProvider->getPassword(ip, username, password))
        return false;

    // first see if connected

    char buf[255];
    buf[0] = 0;
    DWORD len = sizeof(buf);
    DWORD err = WNetGetUser(share.str(),buf,&len);
    if ((err==0)&&(stricmp(username.str(),buf)==0)) {
        // check can access share as well
        for (unsigned i=0;i<10;i++) {
            DWORD ret = (DWORD)GetFileAttributes(share.str()); 
            DWORD err = (ret==(DWORD)-1)?GetLastError():0;
            if (err!=ERROR_IO_INCOMPLETE)
                break;
            Sleep(100*i);
        }
        if (err==0)
            return true;
    }
    for (unsigned retry=0;retry<5;retry++) {
        NETRESOURCE res;
        memset(&res, 0, sizeof(res));
        res.dwType = RESOURCETYPE_DISK;
        res.lpRemoteName = (char *)share.str();
        err = WNetAddConnection2(&res, password.str(), username.str(), 0);
        if (err) {
            if (err==ERROR_SESSION_CREDENTIAL_CONFLICT) {
                WNetCancelConnection2(res.lpRemoteName, 0, false);
                err = WNetAddConnection2(&res, password.str(), username.str(), 0);
            }
            if (err) 
                ERRLOG("WNetAddConnection2(%d): connecting to %s, User: %s",err,res.lpRemoteName,username.str());
        }
        if (err==0)
            return true;
        Sleep(retry*100);
    }
#endif
    return false;
}


static void disconnectFromExternalDrive(const char * const filename)
{
#ifdef _WIN32

    CriticalBlock block(connectcrit);
    StringBuffer share;
    IpAddress ip;
    if (!parseShare(filename,ip,share))
        return;
    if (share.length()&&isShareChar(share.charAt(share.length()))) 
        WNetCancelConnection2((char *)share.str(), 0, 0);
#else
        //TODO: fill in for linux
#endif
}

#ifdef _WIN32



class CWindowsRemoteFile : public CInterface, implements IFile
{
    IFile               *ifile;
    StringAttr          filename;
    bool                connected;

    inline bool connect()
    {
        if (!connected)
            connected = connectToExternalDrive(filename);
        return connected;
    }

public:


    CWindowsRemoteFile(const char * _filename)
        : filename(_filename)
    {
        connected = false;
        ifile = new CFile(_filename);
    }

    ~CWindowsRemoteFile()
    {
        ifile->Release();
#ifdef REMOTE_DISCONNECT_ON_DESTRUCTOR
        if (connected)
            disconnectFromExternalDrive(filename);
#endif

    }

    IMPLEMENT_IINTERFACE

    virtual bool exists()
    {
        connect();
        return ifile->exists();
    }
    virtual bool getTime(CDateTime * createTime, CDateTime * modifiedTime, CDateTime * accessedTime)
    {
        connect();
        return ifile->getTime(createTime, modifiedTime, accessedTime);
    }
    virtual bool setTime(const CDateTime * createTime, const CDateTime * modifiedTime, const CDateTime * accessedTime)
    {
        connect();
        if (ifile->setTime(createTime, modifiedTime, accessedTime))
            return true;
        if (connected||!connect())
            return false;
        return ifile->setTime(createTime, modifiedTime, accessedTime);
    }
    virtual fileBool isDirectory()
    {
        connect();
        fileBool ok = ifile->isDirectory();
        if (ok == notFound && !connected && connect())
            ok = ifile->isDirectory();
        return ok;
    }
    virtual fileBool isFile()
    {
        connect();
        fileBool ok = ifile->isFile();
        if (ok == notFound && !connected && connect())
            ok = ifile->isFile();
        return ok;
    }
    virtual fileBool isReadOnly()
    {
        connect();
        fileBool ok = ifile->isReadOnly();
        if (ok == notFound && !connected && connect())
            ok = ifile->isFile();
        return ok;
    }
    virtual IFileIO * open(IFOmode mode)
    {
        connect();
        return ifile->open(mode);
    }
    virtual IFileIO * openShared(IFOmode mode,IFSHmode shared)
    {
        connect();
        return ifile->openShared(mode,shared);
    }
    virtual IFileAsyncIO * openAsync(IFOmode mode)
    {
        connect();
        return ifile->openAsync(mode);
    }
    virtual const char * queryFilename()
    {
        return ifile->queryFilename();
    }
    virtual bool remove()
    {
        connect();
        unsigned attempt=0;         \
        return ifile->remove();
    }
    virtual void rename(const char *newname)
    {
        connect();
        StringBuffer path;
        splitDirTail(filename,path);
        StringBuffer newdir;
        const char *tail = splitDirTail(newname,newdir);
        if ((newname[0]=='\\')&&(newname[1]=='\\')) { // rename to remote
            if (path.length()&&newdir.length()) {
                if (strcmp(newdir.str(),path.str())!=0) 
                    WARNLOG("CWindowsRemoteFile '%s' to '%s' : directory mismatch",filename.get(),newname);
            }
            newname = tail; // just rename using tail
        }
        ifile->rename(newname);
        path.append(tail);
        filename.set(path);
    }
    virtual void move(const char *newName)
    {
        connect();
        ifile->move(newName);
        filename.set(ifile->queryFilename());
    }
    virtual void setReadOnly(bool ro)
    {
        connect();
        ifile->setReadOnly(ro);             
    }
    virtual offset_t size()
    {
        connect();
        offset_t ret=ifile->size();
        if ((ret==(offset_t)-1)&&!connected&&connect())
            ret=ifile->size();
        return ret;
    }
    virtual bool setCompression(bool set)
    {
        connect();
        return ifile->setCompression(set);
    }
    virtual offset_t compressedSize()
    {
        connect();
        return ifile->compressedSize();
    }

    bool fastCopyFile(CWindowsRemoteFile &target, size32_t buffersize, ICopyFileProgress *progress)
    {
#ifdef _WIN32
        CFile *src = QUERYINTERFACE(ifile,CFile);
        if (!src)
            return false;
        CFile *dst = QUERYINTERFACE(target.ifile,CFile);
        if (!dst)
            return false;
        target.isFile(); // encourage connect on target
        connect();
        return src->fastCopyFile(*dst, buffersize, progress);
#else
        return false;
#endif
    }


    bool fastCopyFile(CFile &target, size32_t buffersize, ICopyFileProgress *progress)
    {
#ifdef _WIN32
        CFile *src = QUERYINTERFACE(ifile,CFile);
        if (!src)
            return false;
        connect();
        return src->fastCopyFile(target, buffersize, progress);
#else
        return false;
#endif
    }

    bool fastCopyFileRev(CFile &src, size32_t buffersize, ICopyFileProgress *progress)
    {
#ifdef _WIN32
        CFile *dst = QUERYINTERFACE(ifile,CFile);
        if (!dst)
            return false;
        connect();
        return src.fastCopyFile(*dst, buffersize, progress);
#else
        return false;
#endif
    }

    void copyTo(IFile *dest, size32_t buffersize, ICopyFileProgress *progress, bool usetmp)
    {
        doCopyFile(dest,this,buffersize,progress,NULL,usetmp);
    }



    bool createDirectory()
    {
        connect();
        return localCreateDirectory(filename);
    }

    IDirectoryIterator *directoryFiles(const char *mask,bool sub,bool includedirs)
    {
        connect();
        return ifile->directoryFiles(mask,sub,includedirs);
    }

    IDirectoryDifferenceIterator *monitorDirectory(
                                  IDirectoryIterator *prev=NULL,    // in (NULL means use current as baseline)
                                  const char *mask=NULL,
                                  bool sub=false,
                                  bool includedirs=false,
                                  unsigned checkinterval=60*1000,
                                  unsigned timeout=(unsigned)-1,
                                  Semaphore *abortsem=NULL) // returns NULL if timed out or abortsem signalled
    {
        connect();
        return ifile->monitorDirectory(prev,mask,sub,includedirs,checkinterval,timeout,abortsem);
    }

    bool getInfo(bool &isdir,offset_t &size,CDateTime &modtime)
    {
        connect();
        return ifile->getInfo(isdir,size,modtime);
    }



    unsigned getCRC()
    {
        connect();
        return ifile->getCRC();
    }

    void setCreateFlags(unsigned cflags)
    {
        ifile->setCreateFlags(cflags);
    }
    void setShareMode(IFSHmode shmode)
    {
        ifile->setShareMode(shmode);
    }

    void copySection(const RemoteFilename &dest, offset_t toOfs, offset_t fromOfs, offset_t size, ICopyFileProgress *progress)
    {
        connect();
        ifile->copySection(dest,toOfs,fromOfs,size,progress);
    }


    IMemoryMappedFile *openMemoryMapped(offset_t ofs, memsize_t len, bool write)
    {
        throw MakeStringException(-1,"Remote file cannot be memory mapped");
        return NULL;
    }

    void treeCopyTo(IFile *dest,IpSubNet &subnet,IpAddress &resfrom, bool usetmp)
    {
        // no special action for windows
        GetHostIp(resfrom);
        copyTo(dest,0x100000,NULL,usetmp);
    }


};
#endif



IFileIO *_createIFileIO(const void *buffer, unsigned sz, bool readOnly)
{
    class CMemoryBufferIO : public CInterface, implements IFileIO
    {
        MemoryBuffer mb;
        void *buffer;
        size32_t sz;
        bool readOnly;
    public:
        IMPLEMENT_IINTERFACE;
        CMemoryBufferIO(const void *_buffer, unsigned _sz, bool _readOnly) : readOnly(_readOnly)
        {
            // JCSMORE - should probably have copy as option
            mb.append(_sz, _buffer);
            buffer = (void *)mb.toByteArray();
            sz = mb.length();
        }
        virtual size32_t read(offset_t pos, size32_t len, void * data)
        {
            if (pos>sz)
                throw MakeStringException(-1, "CMemoryBufferIO: read beyond end of buffer pos=%"I64F"d, len=%d, buffer length=%d", pos, len, mb.length());
            if (pos+len > sz)
                len = (size32_t)(sz-pos);
            memcpy(data, (byte *)buffer+pos, len);
            return len;
        }

        virtual offset_t size() { return sz; }
        virtual size32_t write(offset_t pos, size32_t len, const void * data)
        {
            assertex(!readOnly);
            if (pos+len>sz)
                throw MakeStringException(-1, "CMemoryBufferIO: UNIMPLEMENTED, writing beyond buffer, pos=%"I64F"d, len=%d, buffer length=%d", pos, len, mb.length());
            memcpy((byte *)buffer+pos, data, len);
            return len;
        }

        virtual void setSize(offset_t size)
        {
            if (size > mb.length())
                throw MakeStringException(-1, "CMemoryBufferIO: UNIMPLEMENTED, setting size %"I64F"d beyond end of buffer, buffer length=%d", size, mb.length());
            mb.setLength((size32_t)size);
        }

        offset_t appendFile(IFile *file,offset_t pos,offset_t len)
        {
            if (!file)
                return 0;
            const size32_t buffsize = 0x10000;
            void * buffer = mb.reserve(buffsize);
            Owned<IFileIO> fileio = file->open(IFOread);
            offset_t ret=0;
            while (len) {
                size32_t toread = ((len>=buffsize)||(len<0))?buffsize:(size32_t)len;
                size32_t read = fileio->read(pos,toread,buffer);
                if (read<buffsize) 
                    mb.setLength(mb.length()+read-buffsize);
                if (read==0)
                    break;
                pos += read;
                len -= read;
                ret += read;
            }
            return ret;
        }

    };

    return new CMemoryBufferIO(buffer, sz, readOnly);
}

IFileIO * createIFileI(unsigned len, const void * buffer)
{
    return _createIFileIO((void *)buffer, len, true);
}

IFileIO * createIFileIO(unsigned len, void * buffer)
{
    return _createIFileIO(buffer, len, false);
}

IFileIO * createIFileIO(StringBuffer & buffer)
{
    return _createIFileIO((void *)buffer.toCharArray(), buffer.length(), true);
}

IFileIO * createIFileIO(MemoryBuffer & buffer)
{
    return _createIFileIO(buffer.toByteArray(), buffer.length(), false);
}

//---------------------------------------------------------------------------

class jlib_decl CSequentialFileIO : public CFileIO
{
    offset_t pos;
    
    void checkPos(const char *fn,offset_t _pos)
    {
        if (_pos!=pos)
            throw MakeStringException(-1, "CSequentialFileIO %s out of sequence (%"I64F"d,%"I64F"d)",fn,pos,_pos);
    }

public:
    CSequentialFileIO(HANDLE h,IFSHmode _sharemode)
        : CFileIO(h,_sharemode)
    {
        pos = 0;
    }
    ~CSequentialFileIO()
    {
    }

    IMPLEMENT_IINTERFACE

    size32_t read(offset_t _pos, size32_t len, void * data)
    {
        checkPos("read",_pos);
#ifdef _WIN32
        // Can't use checked_read because don't have the c fileno for it
        DWORD numRead;
        if (ReadFile(file,data,len,&numRead,NULL) == 0) {
            DWORD err = GetLastError();
            if (err==ERROR_BROKEN_PIPE)  // windows returns this at end of pipe
                return 0;
            throw MakeOsException(GetLastError(),"CSequentialFileIO::read"); 
        }
        size32_t ret = (size32_t)numRead;
#else
        size32_t ret = checked_read(file, data, len);
#endif
        pos += ret;
        return ret;
    }
    
    virtual size32_t write(offset_t _pos, size32_t len, const void * data)
    {
        checkPos("write",_pos);

        size32_t ret;
#ifdef _WIN32
        DWORD numWritten;
        if (!WriteFile(file,data,len,&numWritten,NULL))
            throw MakeOsException(GetLastError(),"CSequentialFileIO::write");
        if (numWritten != len)
            throw MakeOsException(DISK_FULL_EXCEPTION_CODE,"CSequentialFileIO::write");
        ret = (size32_t)numWritten;
#else
        ret = ::write(file,data,len);
        if (ret==(size32_t)-1) {
            PrintStackReport();
            ERRLOG("errno(%d): %"I64F"d %u",errno,pos,len);
            throw MakeErrnoException(errno,"CFileIO::write");
        }
        if (ret<len)
            throw MakeOsException(DISK_FULL_EXCEPTION_CODE,"CSequentialFileIO::write");
#endif
        pos += ret;
        return ret;

    }

};

IFileIO * CFile::openShared(IFOmode mode,IFSHmode share)
{
    int stdh = stdIoHandle(filename);
    HANDLE handle = openHandle(mode,share,false, stdh);
    if (handle==NULLFILE)
        return NULL;
#ifndef _WIN32
    set_inherit(handle, false);
#endif
    if (stdh>=0)
        return new CSequentialFileIO(handle,share);
    return new CFileIO(handle,share);
}



//---------------------------------------------------------------------------


extern jlib_decl IFileIO *createIFileIO(HANDLE handle)
{
    return new CFileIO(handle,IFSHfull);
}


offset_t CFileIO::appendFile(IFile *file,offset_t pos,offset_t len)
{
    if (!file)
        return 0;
    CriticalBlock procedure(cs);
    MemoryAttr mb;
    const size32_t buffsize = 0x10000;
    void * buffer = mb.allocate(buffsize);
    Owned<IFileIO> fileio = file->open(IFOread);
    offset_t ret=0;
    offset_t outp = size();
    while (len) {
        size32_t toread = ((len>=buffsize)||(len<0))?buffsize:(size32_t)len;
        size32_t read = fileio->read(pos,toread,buffer);
        if (read==0)
            break;
        size32_t wr = write(outp,read,buffer);
        pos += read;
        outp += wr;
        len -= read;
        ret += wr;
        if (wr!=read)
            break;
    }
    return ret;
}

#ifdef _WIN32

//-- Windows implementation -------------------------------------------------
CFileIO::CFileIO(HANDLE handle, IFSHmode _sharemode)
{
    assertex(handle != NULLFILE);
    throwOnError = false;
    file = handle;
    sharemode = _sharemode;
}

CFileIO::~CFileIO()
{
    if (file != NULLFILE) CloseHandle(file);
    file = NULLFILE;
}

offset_t CFileIO::size()
{
    LARGE_INTEGER pos;
    pos.LowPart = GetFileSize(file, (unsigned long *)&pos.HighPart);
    if (pos.LowPart==-1) {
        DWORD err = GetLastError();
        if (err!=0)     
            throw MakeOsException(err,"CFileIO::size");
    }
    return pos.QuadPart;
}


size32_t CFileIO::read(offset_t pos, size32_t len, void * data)
{
    CriticalBlock procedure(cs);

    DWORD numRead;
    setPos(pos);
    if (ReadFile(file,data,len,&numRead,NULL) == 0)
        throw MakeOsException(GetLastError(),"CFileIO::read");
    return (size32_t)numRead;
}

void CFileIO::setPos(offset_t newPos)
{
    LARGE_INTEGER tempPos;
    tempPos.QuadPart = newPos; 
    tempPos.LowPart = SetFilePointer(file, tempPos.LowPart, &tempPos.HighPart, FILE_BEGIN);
}

size32_t CFileIO::write(offset_t pos, size32_t len, const void * data)
{
    CriticalBlock procedure(cs);

    DWORD numWritten;
    setPos(pos);
    if (!WriteFile(file,data,len,&numWritten,NULL))
        throw MakeOsException(GetLastError(),"CFileIO::write");
    if (numWritten != len)
        throw MakeOsException(DISK_FULL_EXCEPTION_CODE,"CFileIO::write");
    return (size32_t)numWritten;
}


void CFileIO::setSize(offset_t pos)
{
    CriticalBlock procedure(cs);
    setPos(pos);
    if (!SetEndOfFile(file))
        throw MakeOsException(GetLastError(), "CFileIO::setSize");
}

#else

//-- Unix implementation ----------------------------------------------------

// More errorno checking TBD
CFileIO::CFileIO(HANDLE handle, IFSHmode _sharemode)
{
    assertex(handle != NULLFILE);
    throwOnError = false;
    file = handle;
    sharemode = _sharemode;
}

CFileIO::~CFileIO()
{
    if (file != NULLFILE) {
        close(file);
        file=NULLFILE;

    }
}

offset_t CFileIO::size()
{
    CriticalBlock procedure(cs);
    offset_t savedPos = lseek(file,0,SEEK_CUR);
    offset_t length = lseek(file,0,SEEK_END);
    setPos(savedPos);
    return length;
}

size32_t CFileIO::read(offset_t pos, size32_t len, void * data)
{
    if (0==len) return 0;
    return checked_pread(file, data, len, pos);
}

void CFileIO::setPos(offset_t newPos)
{
    if (file != NULLFILE)
        _llseek(file,newPos,SEEK_SET);
}

size32_t CFileIO::write(offset_t pos, size32_t len, const void * data)
{
    size32_t ret = pwrite(file,data,len,pos);
    if (ret==(size32_t)-1) {
        throw MakeErrnoException(errno,"CFileIO::write");
    }
    if (ret<len)
        throw MakeOsException(DISK_FULL_EXCEPTION_CODE,"CFileIO::write");
    return ret;
}

void CFileIO::setSize(offset_t pos)
{
    if (0 != ftruncate(file, pos))
        throw MakeErrnoException(errno, "CFileIO::setSize");
}
#endif

//---------------------------------------------------------------------------

CFileRangeIO::CFileRangeIO(IFileIO * _io, offset_t _headerSize, offset_t _maxLength)
{
    io.set(_io);
    headerSize = _headerSize;
    maxLength = _maxLength;
}

size32_t CFileRangeIO::read(offset_t pos, size32_t len, void * data)
{
    if (pos + len > maxLength)
    {
        if (pos > maxLength)
            pos = maxLength;
        len = (size32_t)(maxLength - pos);
    }
    return io->read(pos+headerSize, len, data);
}

offset_t CFileRangeIO::size()
{
    return maxLength;
}

size32_t CFileRangeIO::write(offset_t pos, size32_t len, const void * data)
{
    if (pos + len > maxLength)
    {
        if (pos > maxLength)
            pos = maxLength;
        len = (size32_t)(maxLength - pos);
    }
    return io->write(pos+headerSize, len, data);
}

//--------------------------------------------------------------------------

offset_t CFileAsyncIO::appendFile(IFile *file,offset_t pos,offset_t len)
{
    // will implemented if needed
    UNIMPLEMENTED; 
}

#ifdef _WIN32

//-- Windows implementation -------------------------------------------------

class CFileAsyncResult: public CInterface, implements IFileAsyncResult
{
protected: friend class CFileAsyncIO;
    OVERLAPPED overlapped;
    DWORD value;
    DWORD wrsize;
    CFileAsyncIO *parent;
public:
    IMPLEMENT_IINTERFACE;
    CFileAsyncResult(offset_t offset,size32_t _wrsize)
    {
        parent = NULL;
        memset(&overlapped,0,sizeof(overlapped));
        overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
        overlapped.Offset = (DWORD)offset;
        overlapped.OffsetHigh = (DWORD)(offset>>32);
        value = (size32_t)-1;
        wrsize = _wrsize;
    }

    ~CFileAsyncResult()
    {
        size32_t dummy;
        getResult(dummy,true);
        CloseHandle(overlapped.hEvent);
    }
    bool getResult(size32_t &ret,bool wait)
    {
        if (value==(size32_t)-1) {
            if (parent) {
                if (GetOverlappedResult(parent->file,&overlapped,&value,wait)==0) {
                    int err = GetLastError();
                    if (err==ERROR_IO_INCOMPLETE) 
                        return false;
                    if (err!=ERROR_HANDLE_EOF) {
                        CriticalBlock block(parent->cs);
                        parent->results.zap(*this,true); // don't delete as array does not own
                        parent = NULL;
                        throw MakeOsException(err,"CFileAsyncResult::getResult");
                    }
                    value = 0;
                }
                CriticalBlock block(parent->cs);
                parent->results.zap(*this,true); // don't delete as array does not own
                parent = NULL;
            }
            else
                return false;
        }
        ret = value;
        if (value<wrsize)
            throw MakeOsException(DISK_FULL_EXCEPTION_CODE,"CFileAsyncResult::getResult");
        return true;
    }
};

CFileAsyncIO::CFileAsyncIO(HANDLE handle, IFSHmode _sharemode)
{
    assertex(handle != NULLFILE);
    throwOnError = false;
    file = handle;
    sharemode = _sharemode;
}

CFileAsyncIO::~CFileAsyncIO()
{
    CriticalBlock block(cs);
    ForEachItemInRev(i,results) {
        size32_t dummy;
        results.item(i).getResult(dummy,true);
    }
    // wait for all outstanding results
    if (file != NULLFILE) CloseHandle(file);
    file = NULLFILE;
}

offset_t CFileAsyncIO::size()
{
    LARGE_INTEGER pos;
    pos.LowPart = GetFileSize(file, (unsigned long *)&pos.HighPart);
    if (pos.LowPart==-1) {
        DWORD err = GetLastError();
        if (err!=0)     
            throw MakeOsException(GetLastError(),"CFileAsyncIO::size");
    }
    return pos.QuadPart;
}

size32_t CFileAsyncIO::read(offset_t pos, size32_t len, void * data)
{
    Owned<IFileAsyncResult> res = readAsync(pos,len,data);
    size32_t ret;
    res->getResult(ret,true);
    return ret;
}

size32_t CFileAsyncIO::write(offset_t pos, size32_t len, const void * data)
{
    Owned<IFileAsyncResult> res = writeAsync(pos,len,data);
    size32_t ret;
    res->getResult(ret,true);
    return ret;
}

void CFileAsyncIO::setSize(offset_t size)
{
    LARGE_INTEGER tempPos;
    tempPos.QuadPart = size; 
    tempPos.LowPart = SetFilePointer(file, tempPos.LowPart, &tempPos.HighPart, FILE_BEGIN);
    if (!SetEndOfFile(file))
        throw MakeOsException(GetLastError(), "CFileIO::setSize");
}


IFileAsyncResult *CFileAsyncIO::readAsync(offset_t pos, size32_t len, void * data)
{
    CFileAsyncResult *res = new CFileAsyncResult(pos,0);
    DWORD val;
    if (ReadFile(file,data,len,&val,&res->overlapped) == 0) {
        int err = GetLastError();
        if (err == ERROR_HANDLE_EOF) { // bit weird
            res->value = 0; // won't need to wait
        }
        else if (err == ERROR_IO_PENDING) {
            CriticalBlock block(cs);
            res->parent = this;
            results.append(*res);
        }
        else
            throw MakeOsException(GetLastError(),"CFileIO::readAsync");
    }   
    else {
        res->value = val; // won't need to wait
    }
    return res;
}

IFileAsyncResult *CFileAsyncIO::writeAsync(offset_t pos, size32_t len, const void * data)
{
    CFileAsyncResult *res = new CFileAsyncResult(pos,len);
    DWORD val;
    if (WriteFile(file,data,len,&val,&res->overlapped) == 0) {
        int err = GetLastError();
        if (err != ERROR_IO_PENDING)
            throw MakeOsException(GetLastError(),"CFileIO::writeAsync");
        CriticalBlock block(cs);
        res->parent = this;
        results.append(*res);
    }   
    else {
        res->value = val; // wont need to wait
    }
    return res;
}



#else

//-- Unix implementation ----------------------------------------------------

class CFileAsyncResult: public CInterface, implements IFileAsyncResult
{
protected: 
    friend class CFileAsyncIO;

    DWORD value;
    DWORD wrsize;

    aiocb cb;

public:
    IMPLEMENT_IINTERFACE;


    CFileAsyncResult(offset_t offset,size32_t _wrsize)
    {
        value = (size32_t)-1;
        wrsize = _wrsize;
    }

    ~CFileAsyncResult()
    {
        size32_t dummy;
        getResult(dummy,true);
    }

    bool getResult(size32_t &ret,bool wait)
    {
        if (value==(size32_t)-1) {
            loop {
                int aio_errno = aio_error(&cb);
                if (aio_errno==ECANCELED)
                    return false;
                if (aio_errno != EINPROGRESS)
                {
                    if (aio_errno)
                        throw MakeErrnoException(aio_errno,"CFileAsyncResult::getResult");
                    value = aio_return(&cb);
                    if (value<wrsize)
                        throw MakeOsException(DISK_FULL_EXCEPTION_CODE,"CFileAsyncResult::getResult");
                    break;
                }
                if (!wait)
                    return false;
                loop {
                    struct timespec timeout;
                    timeout.tv_sec = 60*60*24;  // a long time
                    timeout.tv_nsec = 0;
                    aiocb * cb_list[1];
                    cb_list[0] = &cb;
                    int rc = aio_suspend(cb_list, 1, &timeout);
                    if ((rc == 0)||(errno != EAGAIN))
                        break;
                    if (rc==ECANCELED)
                        return false;
                }
            }
        }
        ret = value;
        return true;
    }
};


CFileAsyncIO::CFileAsyncIO(HANDLE handle, IFSHmode _sharemode)
{
    assertex(handle != NULLFILE);
    throwOnError = false;
    file = handle;
    sharemode = _sharemode;
}


CFileAsyncIO::~CFileAsyncIO()
{
    if (file != NULLFILE) {
        aio_cancel(file,NULL);
        _lclose(file);
    }
    file=NULLFILE;
}

offset_t CFileAsyncIO::size()
{
    CriticalBlock procedure(cs);
    offset_t savedPos = _llseek(file,0,SEEK_CUR);
    offset_t length = _llseek(file,0,SEEK_END);
    _llseek(file, savedPos, SEEK_SET);
    return length;
}

size32_t CFileAsyncIO::read(offset_t pos, size32_t len, void * data)
{
    CriticalBlock procedure(cs);
    _llseek(file,pos,SEEK_SET);
    size32_t ret = _lread(file,data,len);
    if (ret==(size32_t)-1)
        throw MakeErrnoException(errno,"CFileAsyncIO::read");
    return ret;

}

size32_t CFileAsyncIO::write(offset_t pos, size32_t len, const void * data)
{
    CriticalBlock procedure(cs);
    _llseek(file,pos,SEEK_SET);
    size32_t ret = _lwrite(file,data,len);
    if (ret==(size32_t)-1)
        throw MakeErrnoException(errno,"CFileAsyncIO::write");
    return ret;
}

void CFileAsyncIO::setSize(offset_t pos)
{
    CriticalBlock procedure(cs);
    if ((file != NULLFILE)&&(0 != ftruncate(file, pos)))
        throw MakeErrnoException(errno, "CFileIO::setSize");
}

IFileAsyncResult *CFileAsyncIO::readAsync(offset_t pos, size32_t len, void * data)
{
    CFileAsyncResult *res = new CFileAsyncResult(pos,0);
    
    bzero( &(res->cb), sizeof (struct aiocb));
    res->cb.aio_fildes = file;
    res->cb.aio_offset = pos;
    res->cb.aio_buf = data;
    res->cb.aio_nbytes = len;
    res->cb.aio_sigevent.sigev_notify = SIGEV_NONE;

    int retval = aio_read(&(res->cb));
    if (retval==-1)
        throw MakeErrnoException(errno,"CFileAsyncIO::readAsync");
    return res;
}

IFileAsyncResult *CFileAsyncIO::writeAsync(offset_t pos, size32_t len, const void * data)
{
    CFileAsyncResult *res = new CFileAsyncResult(pos,len);

    bzero( &(res->cb), sizeof (struct aiocb));
    res->cb.aio_fildes = file;
    res->cb.aio_offset = pos;
    res->cb.aio_buf = (void*)data;
    res->cb.aio_nbytes = len;
    res->cb.aio_sigevent.sigev_signo = SIGUSR1;
    res->cb.aio_sigevent.sigev_notify = SIGEV_NONE;
    res->cb.aio_sigevent.sigev_value.sival_ptr = (void*)res;

    int retval = aio_write(&(res->cb));
    if (retval==-1)
        throw MakeErrnoException(errno,"CFileAsyncIO::writeAsync");
    return res;
}


#endif


//---------------------------------------------------------------------------

CFileIOStream::CFileIOStream(IFileIO * _io)
{
    io.set(_io);
    curOffset = 0;
}


void CFileIOStream::flush()
{
}


size32_t CFileIOStream::read(size32_t len, void * data)
{
    size32_t numRead = io->read(curOffset, len, data);
    curOffset += numRead;
    return numRead;
}

void CFileIOStream::seek(offset_t pos, IFSmode origin)
{
    switch (origin)
    {
    case IFScurrent:
        curOffset += pos;
        break;
    case IFSend:
        curOffset = io->size() + pos;
        break;
    case IFSbegin:
        curOffset = pos;
        break;
    }
}

offset_t CFileIOStream::size()
{
    return io->size();
}

offset_t CFileIOStream::tell()
{
    return curOffset;
}

size32_t CFileIOStream::write(size32_t len, const void * data)
{
    size32_t numWritten = io->write(curOffset, len, data);
    curOffset += numWritten;
    return numWritten;
}



//---------------------------------------------------------------------------


class CBufferedFileIOStreamBase : public CBufferedIOStreamBase, implements IFileIOStream
{
protected:
    virtual offset_t directSize() = 0;
    offset_t                curOffset;

public:
    IMPLEMENT_IINTERFACE;

    CBufferedFileIOStreamBase(unsigned bufSize) : CBufferedIOStreamBase(bufSize), curOffset(0) { }

    virtual void flush() { doflush(); }




    void seek(offset_t pos, IFSmode origin)
    {
        offset_t newOffset;
        switch (origin)
        {
        case IFScurrent:
            newOffset = tell() + pos;
            break;
        case IFSend:
            newOffset = size() + pos;
            break;
        case IFSbegin:
            newOffset = pos;
            break;
        }

        if (reading)
        {
            // slightly weird but curoffset is end of buffer when reading
            if ((newOffset >= curOffset-numInBuffer) && (newOffset <= curOffset))
            {
                curBufferOffset = (size32_t)(newOffset - (curOffset-numInBuffer));
                return;
            }
        }
        else
        {
            if ((newOffset >= curOffset) && (newOffset <= curOffset + numInBuffer))
            {
                curBufferOffset = (size32_t)(newOffset - curOffset);
                return;
            }
            flush();
        }

        curOffset = newOffset;
        numInBuffer = 0;
        curBufferOffset = 0;
    }

    offset_t size()
    {
        offset_t curSize = directSize();
        if (!reading)
            curSize = std::max(curSize, curOffset + numInBuffer);
        return curSize;
    }

    offset_t tell()
    {
        if (reading)
            return curOffset - numInBuffer + curBufferOffset;
        return curOffset + curBufferOffset;
    }

    size32_t read(size32_t len, void * data)
    {
        return CBufferedIOStreamBase::doread(len, data);
    }

    size32_t write(size32_t len, const void * data)
    {
        if (reading)
            curOffset -= bytesRemaining();

        return CBufferedIOStreamBase::dowrite(len, data);
    }


};


class CBufferedFileIOStream : public CBufferedFileIOStreamBase
{
public:
    CBufferedFileIOStream(IFileIO * _io, unsigned _bufferSize) : CBufferedFileIOStreamBase(_bufferSize), io(_io)
    {
        buffer = new byte[_bufferSize];
    }
    ~CBufferedFileIOStream()
    {
        flush();
        delete [] buffer;
    }

protected:
    virtual void doflush()
    {
        if (!reading && numInBuffer)
        {
            try {
                io->write(curOffset, numInBuffer, buffer);
            }
            catch (IException *) {
                // if we get exception, clear buffer so doen't reoccur on destructor as well
                numInBuffer = 0;
                curBufferOffset = 0;
                throw;
            }
            curOffset += curBufferOffset;
            numInBuffer = 0;
            curBufferOffset = 0;
        }
    }
    virtual bool fillBuffer()
    {
        reading = true;
        numInBuffer = io->read(curOffset, bufferSize, buffer);
        curOffset += numInBuffer;
        curBufferOffset = 0;
        return numInBuffer!=0;
    }
    virtual size32_t directRead(size32_t len, void * data)
    {
        size32_t sz = io->read(curOffset,len,data);
        curOffset += sz;
        return sz;
    }
    virtual size32_t directWrite(size32_t len, const void * data)
    {
        size32_t sz = io->write(curOffset,len,data);
        curOffset += sz;
        return sz;
    }
    virtual offset_t directSize() { return io->size(); }

protected:
    IFileIOAttr             io;
};


//---------------------------------------------------------------------------

class CBufferedAsyncIOStream: public CBufferedFileIOStreamBase
{
    Linked<IFileAsyncIO>    io;
    byte *                  blk1;
    byte *                  blk2;
    IFileAsyncResult        *readasyncres;
    IFileAsyncResult        *writeasyncres;
    bool                    readeof;
public:
    IMPLEMENT_IINTERFACE

    CBufferedAsyncIOStream(IFileAsyncIO * _io, size32_t _bufferSize)
        : CBufferedFileIOStreamBase(_bufferSize/2), io(_io)
    {
        blk1 = new byte[bufferSize];
        blk2 = new byte[bufferSize];
        buffer = blk1;
        readasyncres = NULL;
        writeasyncres = NULL;
        readeof = false;
        minDirectSize = (size32_t)-1; // async always writes using buffer
    }

    ~CBufferedAsyncIOStream()
    {
        flush();
        waitAsyncWrite();
        waitAsyncRead();
        delete [] blk1;
        delete [] blk2;
    }

    void waitAsyncWrite()
    {
        if (writeasyncres) {
            size32_t res;
            writeasyncres->getResult(res,true);
            writeasyncres->Release();
            writeasyncres = NULL;
        }
    }

    size32_t waitAsyncRead()
    {
        size32_t res = 0;
        if (readasyncres) {
            readasyncres->getResult(res,true);
            readasyncres->Release();
            readasyncres = NULL;
        }
        return res;
    }

    void primeAsyncRead(offset_t pos,size32_t size, void *dst)
    {
        assertex(!readasyncres);
        readasyncres = io->readAsync(pos, size, dst);
    }

    void primeAsyncWrite(offset_t pos,size32_t size, const void *src)
    {
        assertex(!writeasyncres);
        writeasyncres = io->writeAsync(pos, size, src);
    }

// CBufferedFileIOStream overloads
    virtual bool fillBuffer()
    {
        if (!reading) {
            waitAsyncWrite();
            reading = true;
        }
        if (readeof) {
            numInBuffer = 0;
            curBufferOffset = 0;
            return false;
        }
        buffer=(buffer==blk1)?blk2:blk1;
        if (readasyncres==NULL)                             // first time
            primeAsyncRead(curOffset, bufferSize, buffer);
        numInBuffer = waitAsyncRead();
        curOffset += numInBuffer;
        curBufferOffset = 0;
        if (numInBuffer)
            primeAsyncRead(curOffset, bufferSize, (buffer==blk1)?blk2:blk1);
        else
            readeof = true;
        return !readeof;
    }
    virtual void doflush()
    {
        if (!reading && numInBuffer)
        {
            waitAsyncWrite();
            primeAsyncWrite(curOffset, numInBuffer, buffer);
            buffer=(buffer==blk1)?blk2:blk1;
            curOffset += curBufferOffset;
            numInBuffer = 0;
            curBufferOffset = 0;
        }
    }
    virtual size32_t directRead(size32_t len, void * data) { assertex(false); return 0; }           // shouldn't get called
    virtual size32_t directWrite(size32_t len, const void * data) { assertex(false); return 0; }    // shouldn't get called
    virtual offset_t directSize() { waitAsyncWrite(); return io->size(); }
};


//-- Helper routines --------------------------------------------------------

static inline size32_t doread(IFileIOStream * stream,void *dst, size32_t size)
{
    size32_t toread=size;
    while (toread)
    {
        int read = stream->read(toread, dst);
        if (!read) 
            return size-toread;
        toread -= read;
        dst = (char *) dst + read;
    }
    return size;
}



CIOStreamReadWriteSeq::CIOStreamReadWriteSeq(IFileIOStream * _stream, offset_t _offset, size32_t _size)
{
    stream.set(_stream);
//  stream->setThrowOnError(true);
    size = _size;
    offset = _offset;  // assumption that stream at correct location already
}

void CIOStreamReadWriteSeq::put(const void *src)
{
    stream->write(size, src);
}

void CIOStreamReadWriteSeq::putn(const void *src, unsigned n)
{
    stream->write(size*n, src);
}

void CIOStreamReadWriteSeq::flush()
{
    stream->flush();
}

offset_t CIOStreamReadWriteSeq::getPosition()
{
    return stream->tell();
}

bool CIOStreamReadWriteSeq::get(void *dst)
{
    return doread(stream,dst,size)==size;
}

unsigned CIOStreamReadWriteSeq::getn(void *dst, unsigned n)
{
    return doread(stream,dst,size*n)/size;
}

void CIOStreamReadWriteSeq::reset()
{
    stream->seek(offset, IFSbegin);
}




//-- Helper routines --------------------------------------------------------

size32_t read(IFileIO * in, offset_t pos, size32_t len, MemoryBuffer & buffer)
{
    const size32_t checkLengthLimit = 0x1000;
    if (len >= checkLengthLimit)
    {
        //Don't allocate a stupid amount of memory....
        offset_t fileLength = in->size();
        if (pos > fileLength)
            pos = fileLength;
        if ((len == (size32_t)-1) || (pos + len > fileLength))
            len = (size32_t)(fileLength - pos);
    }
    void * data = buffer.reserve(len);
    size32_t lenRead = in->read(pos, len, data);
    if (lenRead != len)
        buffer.rewrite(buffer.length() - (len - lenRead));
    return lenRead;
}

void copyFile(const char *target, const char *source, size32_t buffersize, ICopyFileProgress *progress)
{
    OwnedIFile src = createIFile(source);
    if (!src)
        throw MakeStringException(-1, "copyFile: source '%s' not found", source);
    OwnedIFile tgt = createIFile(target);
    if (!tgt)
        throw MakeStringException(-1, "copyFile: target path '%s' could not be created", target);
    copyFile(tgt, src, buffersize,progress);
}

void copyFile(IFile * target, IFile * source, size32_t buffersize, ICopyFileProgress *progress)
{
    source->copyTo(target,buffersize,progress);
}

void doCopyFile(IFile * target, IFile * source, size32_t buffersize, ICopyFileProgress *progress, ICopyFileIntercept *copyintercept, bool usetmp)
{
    if (!buffersize)
        buffersize = 0x100000;
#ifdef _WIN32
    if (!usetmp) { 
        CFile *src = QUERYINTERFACE(source,CFile);
        CFile *dst = QUERYINTERFACE(target,CFile);
        if (src) {
            if (dst) {
                if (src->fastCopyFile(*dst, buffersize, progress))
                    return;
            }
            CWindowsRemoteFile *dst2 = QUERYINTERFACE(target,CWindowsRemoteFile);
            if (dst2) {
                if (dst2->fastCopyFileRev(*src, buffersize, progress))
                    return;
            }
        }
        CWindowsRemoteFile *src2 = QUERYINTERFACE(source,CWindowsRemoteFile);
        if (src2) {
            if (dst) {
                if (src2->fastCopyFile(*dst,buffersize, progress))
                    return;
            }
            CWindowsRemoteFile *dst2 = QUERYINTERFACE(target,CWindowsRemoteFile);
            if (dst2) {
                if (src2->fastCopyFile(*dst2, buffersize, progress))
                    return;
            }
        }
    }
#endif
    OwnedIFileIO sourceIO = source->open(IFOread);
    if (!sourceIO)
        throw MakeStringException(-1, "copyFile: source '%s' not found", source->queryFilename());

#ifdef __linux__

    // this is not really needed in windows - if it is we will have to
    // test the file extenstion - .exe, .bat
    
    struct stat info;
    if (stat(source->queryFilename(), &info) == 0)  // cannot fail - exception would have been thrown above
        target->setCreateFlags(info.st_mode&(S_IRUSR|S_IRGRP|S_IROTH|S_IWUSR|S_IWGRP|S_IWOTH|S_IXUSR|S_IXGRP|S_IXOTH));
#endif
    Owned<IFileIO> targetIO;
    Owned<IFile> tmpfile;
    IFile *dest;
    if (usetmp) {
        StringBuffer tmpname;
        makeTempCopyName(tmpname,target->queryFilename());
        tmpfile.setown(createIFile(tmpname.str()));
        dest = tmpfile;
    }
    else
        dest = target;
    targetIO.setown(dest->open(IFOcreate));
    if (!targetIO)
        throw MakeStringException(-1, "copyFile: target path '%s' could not be created", dest->queryFilename());
    MemoryAttr mb;
    void * buffer = copyintercept?NULL:mb.allocate(buffersize);
    
    offset_t offset = 0;
    offset_t total; 
    Owned<IException> exc;
    try
    {
        if (progress)
            total = sourceIO->size(); // only needed for progress
        loop
        {
            size32_t got;
            if (copyintercept) {
                got = (size32_t)copyintercept->copy(sourceIO,targetIO,offset,buffersize);
                if (got == 0)
                    break;
            }
            else {
                got = sourceIO->read(offset, buffersize, buffer);
                if (got == 0)
                    break;
                targetIO->write(offset, got, buffer);
            }
            offset += got;
            if (progress && progress->onProgress(offset, total) != CFPcontinue)
                break;
        }
        targetIO.clear();
        if (usetmp) {
            StringAttr tail(pathTail(target->queryFilename()));
            target->remove();
            dest->rename(tail);
        }
    }
    catch (IException *e)
    {
        // try to delete partial copy
        StringBuffer s;
        s.append("copyFile target=").append(dest->queryFilename()).append(" source=").append(source->queryFilename()).appendf("; read/write failure (%d): ",e->errorCode());
        exc.setown(MakeStringException(e->errorCode(), "%s", s.str()));
        e->Release();
        EXCLOG(exc, "doCopyFile");
    }
    if (exc.get()) {
        try {
            sourceIO.clear();
        }
        catch (IException *e) { 
            EXCLOG(e, "doCopyFile closing source"); 
            e->Release();
        }
        try {
            targetIO.clear();
        }
        catch (IException *e) { 
            EXCLOG(e, "doCopyFile closing dest"); 
            e->Release();
        }
        try { 
            dest->remove(); 
        } 
        catch (IException *e) { 
            StringBuffer s;
            EXCLOG(e, s.clear().append("Removing partial copy file: ").append(dest->queryFilename()).str()); 
            e->Release();
        }
        throw exc.getClear();
    }
    CDateTime createTime, modifiedTime;
    if (source->getTime(&createTime, &modifiedTime, NULL))
        target->setTime(&createTime, &modifiedTime, NULL);
}



void makeTempCopyName(StringBuffer &tmpname,const char *destname)
{
    // simple for the moment (maybe used uid later)
    tmpname.append(destname).append("__");
#ifdef _WIN32
    genUUID(tmpname,true);
#else
    genUUID(tmpname);
#endif
    tmpname.append(".tmp");
}


//---------------------------------------------------------------------------

#ifndef _WIN32
/// This code is dangerous - pass it arrays smaller than _MAX_xxx and it will write off the end even if you KNOW your strings would fit
// Should NOT use strncpy here

void _splitpath(const char *path, char *drive, char *dir, char *fname, char *ext)
{
    strncpy(dir, path, (_MAX_DIR-1));

    char* last = strrchr(dir, '.');
    if (last != NULL)
    {
        if (strrchr(last, PATHSEPCHAR)==NULL)
        {
            strncpy(ext, last, (_MAX_EXT-1));
            *last = '\0';
        }
        else
        {
            *ext = '\0';
        }
    }
    else
    {
        *ext = '\0';
    }

    last = strrchr(dir, PATHSEPCHAR);
    if (last != NULL)
    {
        strncpy(fname, ++last, (_MAX_FNAME-1));
        *last = '\0';
    }
    else
    {
        strncpy(fname, dir, (_MAX_FNAME-1));
        *dir = '\0';
    }

    *drive = '\0';
}

#endif


void splitFilename(const char * filename, StringBuffer * drive, StringBuffer * path, StringBuffer * tail, StringBuffer * ext)
{
    char tdrive[_MAX_DRIVE];
    char tdir[_MAX_DIR];
    char ttail[_MAX_FNAME];
    char text[_MAX_EXT];

    ::_splitpath(filename, tdrive, tdir, ttail, text);
    if (drive)
        drive->append(tdrive);
    if (path)
        path->append(tdir);
    if (tail)
        tail->append(ttail);
    if (ext)
        ext->append(text);
}


StringBuffer &createUNCFilename(const char * filename, StringBuffer &UNC, bool useHostNames)
{
    char buf[255];
#ifdef _WIN32
    char *dummy;
    GetFullPathName(filename, sizeof(buf), buf, &dummy);
    if (buf[1]==':')
    {
        // MORE - assumes it's a local drive not a mapped one
        UNC.append("\\\\");
        if (useHostNames)
            UNC.append(GetCachedHostName());
        else
            queryHostIP().getIpText(UNC);
        UNC.append("\\").append((char)tolower(buf[0])).append(getShareChar()).append(buf+2);
    }
    else 
    {
        assertex(buf[0]=='\\' && buf[1]=='\\');
        UNC.append(buf);
    }
    return UNC;
#else
    if (filename[0]=='/' && filename[1]=='/')
        UNC.append(filename);
    else
    {
        UNC.append("//");
        if (useHostNames)
            UNC.append(GetCachedHostName());
        else
            queryHostIP().getIpText(UNC);

        if (*filename != '/')
        {
            getcwd(buf, sizeof(buf));
            UNC.append(buf).append("/");
        }
        UNC.append(filename);
    }
    return UNC;
#endif
}

bool splitUNCFilename(const char * filename, StringBuffer * machine, StringBuffer * path, StringBuffer * tail, StringBuffer * ext)
{
    if (!filename || !isPathSepChar(filename[0]) || !isPathSepChar(filename[1]))
        return false;
    const char * cur = filename+2;
    while (*cur && !isPathSepChar(*cur))
        cur++;
    if (!*cur)
        return false;

    const char * startPath = cur;
    const char * lastExt = NULL;
    const char * startTail = NULL;
    char next;
    while ((next = *cur) != 0)
    {
        if (isPathSepChar(next))
        {
            lastExt = NULL;
            startTail = cur+1;
        }
        else if (next == '.')
            lastExt = cur;
        cur++;
    }
    assertex(startTail);
    if (machine)
        machine->append(startPath-filename, filename);
    if (path)
        path->append(startTail - startPath, startPath);
    if (lastExt)
    {
        if (tail)
            tail->append(lastExt - startTail, startTail);
        if (ext)
            ext->append(lastExt);
    }
    else
    {
        if (tail)
            tail->append(startTail);
    }
    return true;
}

/** 
 *  Ensure the filename has desired extension.
 *  If it has no extension, add the desired extension, return true.
 *  If it has an extension different from the desiredExtension, return false.
 *  Otherwise, return true.
 */
bool ensureFileExtension(StringBuffer& filename, const char* desiredExtension)
{
    char drive[_MAX_DRIVE];
    char dir[_MAX_DIR];
    char fname[_MAX_FNAME];
    char ext[_MAX_EXT];
    
    _splitpath(filename.str(), drive, dir, fname, ext);
    if (ext[0]==0)
    {
        filename.append(desiredExtension);
        return true;
    }

    if (strcmp(ext,desiredExtension)!=0)
        return false;

    return true;
}

/* Get full file name. If noExtension is true, the extesion (if any) will be trimmed */ 
StringBuffer& getFullFileName(StringBuffer& filename, bool noExtension)
{
    char drive[_MAX_DRIVE];
    char dir[_MAX_DIR];
    char fname[_MAX_FNAME];
    char ext[_MAX_EXT];
    
    _splitpath(filename.str(), drive, dir, fname, ext);
    
    filename.clear();
    filename.append(drive).append(dir).append(fname);
    if (!noExtension)
        filename.append(ext);

    return filename;
}

/* Get the file name only. If noExtension is true, the extension (if any) will be trimmed */ 
StringBuffer& getFileNameOnly(StringBuffer& filename, bool noExtension)
{
    char drive[_MAX_DRIVE];
    char dir[_MAX_DIR];
    char fname[_MAX_FNAME];
    char ext[_MAX_EXT];
    
    _splitpath(filename.str(), drive, dir, fname, ext);
    
    filename.clear();
    filename.append(fname);
    if (!noExtension)
        filename.append(ext);

    return filename;
}

//---------------------------------------------------------------------------


class CNullDirectoryIterator : public CInterface, implements IDirectoryIterator
{
public:
    IMPLEMENT_IINTERFACE;

    bool  first()
    {
        return false;
    }

    bool  next()
    {
        return false;
    }

    StringBuffer &getName(StringBuffer &buf)
    {
        return buf;
    }

    __int64 getFileSize()
    {
        return -1;
    }


    bool getModifiedTime(CDateTime &ret)
    {
        return false;
    }

    virtual bool isValid()  { return false; }
    virtual IFile & query() { return *(IFile *)NULL; }
    virtual bool isDir() {  return false; }

};


class CDirectoryIterator : public CInterface, implements IDirectoryIterator
{
public:
    CDirectoryIterator(const char * _path, const char * _mask, bool _sub, bool _includedir)
    {
        StringBuffer tmp;
        if (!_path || !*_path) 
            _path = "." PATHSEPSTR;
        else if (_path[strlen(_path)-1] != PATHSEPCHAR)
            _path = tmp.append(_path).append(PATHSEPCHAR);
        path.set(_path);
        mask.set(_mask);
        sub = _sub;
        includedir = _includedir;
        subidx = 0;
        curisdir = false;
    }

    IMPLEMENT_IINTERFACE

    virtual bool first()=0;
    virtual bool next()=0;
    virtual bool isValid()  { return cur != NULL; }
    virtual IFile & query() { return *cur; }
    virtual StringBuffer &getName(StringBuffer &buf)=0;
    virtual bool isDir() {  return curisdir; }
protected:  
    Owned<IFile>    cur;
    bool            curisdir;
    StringAttr      path;
    StringAttr      mask;
    bool            includedir;
    bool            sub;    // TBD
    StringAttrArray subpaths;
    unsigned        subidx; // -1 to index subpaths
};

#ifdef _WIN32

class CWindowsDirectoryIterator : public CDirectoryIterator
{
    WIN32_FIND_DATA info;
    HANDLE          handle;


    bool setCurrent()
    {
        if (strcmp(info.cFileName, ".") == 0 || strcmp(info.cFileName, "..") == 0)
            return false;
        bool match = (!mask.length() || WildMatch(info.cFileName, mask, true));
        curisdir = (info.dwFileAttributes&FILE_ATTRIBUTE_DIRECTORY)!=0;
        if (!match&&!curisdir)
            return false;
        StringBuffer f(path);
        if (subidx) 
            f.append(subpaths.item(subidx-1).text).append('\\');
        f.append(info.cFileName);
        if (curisdir) {
            if (sub) {
                const char *s = f.str()+path.length();
                unsigned i;
                for (i=0;i<subpaths.ordinality();i++)
                    if (stricmp(subpaths.item(i).text,s)==0)
                        break;
                if (i==subpaths.ordinality())
                    subpaths.append(*new StringAttrItem(s));
            }
            if (!includedir)
                return false;
        }
        if (!match)
            return false;
        cur.setown(createIFile(f.str()));
        return true;
    }

    bool open()
    {
        close();
        while (subidx<=subpaths.ordinality()) {
            StringBuffer location(path);
            if (subidx)
                location.append(subpaths.item(subidx-1).text).append('\\');
            location.append("*");
            handle = FindFirstFile(location.str(), &info);
            if (handle != INVALID_HANDLE_VALUE)
                return true;
            subidx++;
        }
        return false;
    }

    void close()
    {
        cur.clear();
        if (handle != INVALID_HANDLE_VALUE) {
            FindClose(handle);
            handle = INVALID_HANDLE_VALUE;
        }
    };


public:
    CWindowsDirectoryIterator(const char * _path, const char * _mask, bool _sub, bool _includedir)
        : CDirectoryIterator(_path,_mask,_sub,_includedir)
    {
        handle = INVALID_HANDLE_VALUE;
    }

    ~CWindowsDirectoryIterator()
    {
        close();
    }


    bool first()
    {
        subpaths.kill();
        subidx = 0;
        if (!open())
            return false;
        if (setCurrent())
            return true;
        return next();
    }

    bool next()
    {
        loop {
            loop {
                if (!FindNextFile(handle, &info))
                    break;
                if (setCurrent())
                    return true;
            }
            subidx++;
            if (!open())
                break;
            if (setCurrent())
                return true;
        }
        return false;
    }

    StringBuffer &getName(StringBuffer &buf)
    {
        if (subidx)
            buf.append(subpaths.item(subidx-1).text).append('\\');
        return buf.append(info.cFileName);
    }


    __int64 getFileSize()
    {
        if (curisdir)
            return -1;
        LARGE_INTEGER x;
        x.LowPart = info.nFileSizeLow;
        x.HighPart = info.nFileSizeHigh;
        return x.QuadPart;
    }


    bool getModifiedTime(CDateTime &ret)
    {
        FILETIMEtoIDateTime(&ret, info.ftLastWriteTime);
        return true;
    }


};


IDirectoryIterator * createDirectoryIterator(const char * path, const char * mask)
{
    if (mask&&!*mask)   // only NULL is wild
        return new CNullDirectoryIterator;
    if (!path || !*path) // cur directory so no point in checking for remote etc.
        return new CWindowsDirectoryIterator(path, mask,false,true);
    OwnedIFile iFile = createIFile(path);
    if (!iFile||(iFile->isDirectory()!=foundYes))
        return new CNullDirectoryIterator;
    return iFile->directoryFiles(mask, false, true);
}

IDirectoryIterator *CFile::directoryFiles(const char *mask,bool sub,bool includedirs)
{
    if ((mask&&!*mask)||    // only NULL is wild
        (isDirectory()!=foundYes))
        return new CNullDirectoryIterator;
    return new CWindowsDirectoryIterator(filename, mask,sub,includedirs);
}

bool CFile::getInfo(bool &isdir,offset_t &size,CDateTime &modtime)
{
    WIN32_FILE_ATTRIBUTE_DATA info;
    if (GetFileAttributesEx(filename, GetFileExInfoStandard, &info) != 0) {
        LARGE_INTEGER x;
        x.LowPart = info.nFileSizeLow;
        x.HighPart = info.nFileSizeHigh;
        size = (offset_t)x.QuadPart;
        isdir = (info.dwFileAttributes != (DWORD)-1)&&(info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY);
        FILETIMEtoIDateTime(&modtime, info.ftLastWriteTime);
        return true;
    }
    size = 0;
    modtime.clear();
    isdir = false;
    return false;
}


#else

class CLinuxDirectoryIterator : public CDirectoryIterator
{
    StringAttr      tail;
    DIR *           handle;
    struct stat     st;
    bool            gotst;

    bool loadst()
    {
        if (!gotst&&cur)
            gotst = (stat(cur->queryFilename(), &st) == 0);
        return gotst;
    }
    
    
public:
    CLinuxDirectoryIterator(const char * _path, const char * _mask, bool _sub,bool _includedir)
        : CDirectoryIterator(_path,_mask,_sub,_includedir)
    {
        handle = NULL;
        gotst = false;
    }

    ~CLinuxDirectoryIterator()
    {
        close();
    }

    bool open()
    {
        close();
        while (subidx<=subpaths.ordinality()) {
            StringBuffer location(path);
            if (subidx)
                location.append(subpaths.item(subidx-1).text);
            // not sure if should remove trailing '/'  
            handle = ::opendir(location.str());
            // better error handling here?
            if (handle)
                return true;
            subidx++;
        }
        return false;
    }

    void close()
    {
        cur.clear();
        if (handle) {
            closedir(handle);
            handle = NULL;
        }
    }

    bool first()
    {
        subpaths.kill();
        subidx = 0;
        if (open()) 
            return next();
        return false;
    }

    bool next()
    {
        loop {
            struct dirent *entry;
            loop {
                gotst = false;
                entry = readdir(handle);  // don't need _r here 
                // need better checking here?
                if (!entry)
                    break;
                if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0) 
                    continue;

                bool match = (!mask.length() || WildMatch(entry->d_name, mask, false));
                curisdir = (entry->d_type==DT_DIR);
                bool islnk = (entry->d_type==DT_LNK);
                bool isunknown = (entry->d_type==DT_UNKNOWN); // to work around xfs bug
                if (match||curisdir||islnk||isunknown) {
                    StringBuffer f(path);
                    if (subidx) 
                        f.append(subpaths.item(subidx-1).text).append('/');
                    f.append(entry->d_name);
                    if (islnk||isunknown) {
                        struct stat info;
                        if (stat(f.str(), &info) == 0)  // will follow link
                            curisdir = S_ISDIR(info.st_mode);
                        else
                            curisdir = false;
                    }
                    if (curisdir) {
                        if (sub) {
                            const char *s = f.str()+path.length();
                            unsigned i;
                            for (i=0;i<subpaths.ordinality();i++)
                                if (strcmp(subpaths.item(i).text,s)==0)
                                    break;
                            if (i==subpaths.ordinality())
                                subpaths.append(*new StringAttrItem(s));
                        }
                        if (!includedir)
                            match = false;
                    }
                    if (match) {
                        tail.set(entry->d_name);
                        cur.setown(createIFile(f.str()));
                        return true;
                    }
                }
            }
            subidx++;
            if (!open())
                break;
        }
        return false;
    }

    StringBuffer &getName(StringBuffer &buf)
    {
        if (subidx)
            buf.append(subpaths.item(subidx-1).text).append('/');
        return buf.append(tail);
    }

    __int64 getFileSize()
    {
        if (curisdir)
            return -1;
        if (!loadst())
            return -1;
        return st.st_size ;
    }


    bool getModifiedTime(CDateTime &ret)
    {
        if (!loadst())
            return false;
        timetToIDateTime(&ret,st.st_mtime);
        return true;
    }

};

IDirectoryIterator * createDirectoryIterator(const char * path, const char * mask)
{
    if (mask&&!*mask)   // only NULL is wild
        return new CNullDirectoryIterator;
    if (!path || !*path) // no point in checking for remote etc.
        return new CLinuxDirectoryIterator(path, mask,false,true);
    OwnedIFile iFile = createIFile(path);
    if (!iFile||(iFile->isDirectory()!=foundYes))
        return new CNullDirectoryIterator;
    return iFile->directoryFiles(mask, false, true);
}

IDirectoryIterator *CFile::directoryFiles(const char *mask,bool sub,bool includedirs)
{
    if ((mask&&!*mask)||    // only NULL is wild
        (isDirectory()!=foundYes))
        return new CNullDirectoryIterator;
    return new CLinuxDirectoryIterator(filename, mask,sub,includedirs);
}


bool CFile::getInfo(bool &isdir,offset_t &size,CDateTime &modtime)
{
    struct stat info;
    if (stat(filename, &info) == 0) {
        size = (offset_t)info.st_size;
        isdir = S_ISDIR(info.st_mode);
        timetToIDateTime(&modtime,  info.st_mtime);
        return true;
    }
    size = 0;
    modtime.clear();
    isdir = false;
    return false;
}


#endif


class CDirEntry: extends CInterface
{
public:
    StringAttr name;
    Owned<IFile> file;
    __int64 size;
    CDateTime modified;
    byte flags; // IDDI*
    bool isdir;

    CDirEntry(IDirectoryIterator *iter)
    {
        StringBuffer n;
        name.set(iter->getName(n).str());
        size = iter->getFileSize();
        iter->getModifiedTime(modified);
        file.set(&iter->query());
        flags = 0;
        isdir = iter->isDir();
    }

    bool match(byte f) 
    {
        return (flags==0)||((f&flags)!=0);
    }

    int compare(const CDirEntry *e)
    {
        return strcmp(name.get(),e->name.get());
    }

    int compareProp(const CDirEntry *e)
    {
        int c = compare(e);
        if (c)
            return c;
        if (isdir!=e->isdir)
            return isdir?-1:1;
        if (size!=e->size)
            return (size<e->size)?-1:1;
        return modified.compare(e->modified,false);
    }

};


class CDirectoryDifferenceIterator : public CIArrayOf<CDirEntry>, extends CInterface, implements IDirectoryDifferenceIterator
{

    
    
    static int compare(CInterface **_a, CInterface **_b)
    {
        CDirEntry *a = *(CDirEntry **)_a;
        CDirEntry *b = *(CDirEntry **)_b;
        return a->compare(b);
    }
    unsigned idx;
    byte mask;

public:
    IMPLEMENT_IINTERFACE;
    CDirectoryDifferenceIterator(IDirectoryIterator *iter, CDirectoryDifferenceIterator *cmp)
    {
        mask = IDDIstandard;
        idx = 0;
        ForEach(*iter) 
            append(*new CDirEntry(iter));
        CIArrayOf<CDirEntry>::sort(compare);
        if (cmp) {  // assumes cmp sorted
            unsigned i = 0;
            unsigned ni = ordinality();
            unsigned j = 0;
            unsigned nj = cmp->ordinality();
            loop {
                CDirEntry *a = NULL;
                CDirEntry *b = NULL;
                if (i>=ni) {
                    if (j>=nj)
                        break;
                    b = &cmp->item(j++);
                }
                else if (j>=nj) {
                    a = &item(i++);
                }
                else {
                    a = &item(i);
                    b = &cmp->item(j);
                    int c = a->compare(b);
                    if (c==0) {
                        if (a->compareProp(b)==0) {
                            a->flags = IDDIunchanged;
                            a = NULL;
                            b = NULL;
                        }
                        i++;
                        j++;
                    }
                    else if (c<0) {
                        b = NULL; 
                        i++;
                    }
                    else {
                        a = NULL;
                        j++;
                    }
                }
                if (a) {
                    if (b)
                        a->flags|=IDDImodified;
                    else
                        a->flags|=IDDIadded;
                }
                else if (b) {
                    b->Link();
                    b->flags = IDDIdeleted;
                    add(*b,i);
                    i++;
                    ni++;
                }
            }                   
        }
    }
    virtual bool first()
    {
        idx = 0;
        while (idx<ordinality()) {
            if (item(idx).match(mask))
                return true;
            idx++;
        }
        return false;
    }
    virtual bool next()
    {
        idx++;
        while (idx<ordinality()) {
            if (item(idx).match(mask))
                return true;
            idx++;
        }
        return false;
    }
    virtual bool isValid()  
    {
        return (idx<ordinality());
    }
    virtual IFile & query() 
    {
        if (isValid())
            return *item(idx).file;
        return *(IFile *) NULL;
    }
    virtual StringBuffer &getName(StringBuffer &buf)
    {
        if (isValid())
            buf.append(item(idx).name);
        return buf;
    }
    virtual bool isDir() 
    {
        if (isValid())
            return item(idx).isdir;
        return false;
    }
    __int64 getFileSize()
    {
        if (isValid())
            return item(idx).isdir?0:item(idx).size;
        return 0;
    }
    virtual bool getModifiedTime(CDateTime &ret)
    {
        if (isValid()) {
            ret.set(item(idx).modified);
        }
        return false;
    }

    virtual void setMask(unsigned _mask)
    {
        mask = (byte)_mask;
    }

    virtual unsigned getFlags() 
    {
        if (isValid())
            return item(idx).flags;
        return 0;
    }

    unsigned numChanges()
    {
        unsigned ret=0;
        ForEachItemIn(i,*this) {
            byte f = item(i).flags;
            if ((f!=0)&&(f!=IDDIunchanged))
                ret++;
        }
        return ret;
    }
};



IDirectoryDifferenceIterator *CFile::monitorDirectory(IDirectoryIterator *_prev,            // in
                             const char *mask,
                             bool sub,
                             bool includedirs,
                             unsigned checkinterval,
                             unsigned timeout,
                             Semaphore *abortsem)
{
    Linked<IDirectoryIterator> prev;
    if (_prev)
        prev.set(_prev);
    else
        prev.setown(directoryFiles(mask,sub,includedirs));
    if (!prev)
        return NULL;
    Owned<CDirectoryDifferenceIterator> base = new CDirectoryDifferenceIterator(prev,NULL);
    prev.clear(); // not needed now
    unsigned start=msTick();
    loop {
        if (abortsem) {
            if (abortsem->wait(checkinterval))
                break;
        }
        else
            Sleep(checkinterval);
        Owned<IDirectoryIterator> current = directoryFiles(mask,sub,includedirs);
        if (!current)
            break;
        Owned<CDirectoryDifferenceIterator> cmp = new CDirectoryDifferenceIterator(current,base);
        current.clear();
        if (cmp->numChanges())
            return cmp.getClear();
        if (msTick()-start>timeout)
            break;
    }
    return NULL; // timed out
}



//---------------------------------------------------------------------------

class FixedPasswordProvider : public CInterface, implements IPasswordProvider
{
public:
    FixedPasswordProvider(const char * _username, const char * _password) { username.set(_username); password.set(_password); }
    IMPLEMENT_IINTERFACE;

    virtual bool getPassword(const IpAddress & ip, StringBuffer & _username, StringBuffer & _password)
    {
        _username.append(username.get());
        _password.append(password.get());
        return true;
    }

protected:
    StringAttr      username;
    StringAttr      password;
};

IPasswordProvider * queryPasswordProvider()
{
    return passwordProvider;
}

void setPasswordProvider(IPasswordProvider * provider)
{
    passwordProvider.set(provider);
}

void setDefaultUser(const char * username,const char *password)
{
    Owned<IPasswordProvider> provider = new FixedPasswordProvider(username, password);
    setPasswordProvider(provider);
}

//---------------------------------------------------------------------------




    



bool recursiveCreateDirectory(const char * path)
{
#ifndef _WIN32
#ifdef USE_SAMBA
    return localCreateDirectory(path);
#endif
#endif
    Owned<IFile> file = createIFile(path);
    return file->createDirectory();
}

bool recursiveCreateDirectoryForFile(const char *fullFileName)
{
    StringBuffer path;
    splitFilename(fullFileName, &path, &path, NULL, NULL);
    return recursiveCreateDirectory(path.str());
}



//---------------------------------------------------------------------------


size32_t DirectBufferI::read(offset_t pos, size32_t len, void * data)
{
    if (pos + len > buffLen)
    {
        if (pos > buffLen)
            pos = buffLen;
        len = (size32_t)(buffLen - pos);
    }
    memcpy(data, buffer+pos, len);
    return len;
}

size32_t DirectBufferI::write(offset_t pos, size32_t len, const void * data)
{
    UNIMPLEMENTED;
}

size32_t DirectBufferIO::write(offset_t pos, size32_t len, const void * data)
{
    if (pos + len > buffLen)
    {
        if (pos > buffLen)
            pos = buffLen;
        len = (size32_t)(buffLen - pos);
    }
    memcpy(buffer+pos, data, len);
    return len;
}


//---------------------------------------------------------------------------

size32_t StringBufferIO::read(offset_t pos, size32_t len, void * data)
{
    unsigned strLen = buffer.length();
    if (pos + len > strLen)
    {
        if (pos > strLen)
            pos = strLen;
        len = (size32_t)(strLen - pos);
    }
    buffer.getChars((size32_t)pos, (size32_t)(pos+len), (char *)data);
    return len;
}

offset_t StringBufferIO::size()
{
    return buffer.length();
}

size32_t StringBufferIO::write(offset_t pos, size32_t len, const void * data)
{
    unsigned strLen = buffer.length();
    buffer.ensureCapacity((size32_t)(pos+len));
    memcpy((byte *)buffer.toCharArray() + pos, data, len);
    return len;
}

void StringBufferIO::setSize(offset_t size)
{
    if (size > buffer.length())
        buffer.ensureCapacity((size32_t)size);
    else
        buffer.setLength((size32_t)size);
}

//---------------------------------------------------------------------------

size32_t MemoryBufferIO::read(offset_t pos, size32_t len, void * data)
{
    unsigned strLen = buffer.length();
    if (pos + len > strLen)
    {
        if (pos > strLen)
            pos = strLen;
        len = (size32_t)(strLen - pos);
    }
    memcpy(data, buffer.toByteArray() + pos, len);
    return len;
}

offset_t MemoryBufferIO::size()
{
    return buffer.length();
}

size32_t MemoryBufferIO::write(offset_t pos, size32_t len, const void * data)
{
    unsigned strLen = buffer.length();
    buffer.ensureCapacity((size32_t)(pos+len));
    memcpy((byte *)buffer.toByteArray() + pos, data, len);
    return len;
}

void MemoryBufferIO::setSize(offset_t size)
{
    if (size > buffer.length())
        buffer.ensureCapacity((size32_t)size);
    else
        buffer.setLength((size32_t)size);
}

//---------------------------------------------------------------------------

IFile * createIFile(const char * filename)
{
    if (!filename)
        return NULL;
    bool linremote=(memcmp(filename,"//",2)==0);
    if (!linremote&&(memcmp(filename,"\\\\",2)!=0)) // see if remote looking
        return new CFile(filename);
    RemoteFilename rfn;
    rfn.setRemotePath(filename);
    if (rfn.isNull())
        throw MakeStringException(-1, "CreateIFile cannot resolve %s", filename);
    if (rfn.isLocal()) { // ignore dafilesrv request if local and standard port
        StringBuffer tmplocal;
        return new CFile(rfn.getLocalPath(tmplocal).str());
    }
#ifdef _WIN32
    StringBuffer tmplocal;
    if (linremote||(rfn.queryEndpoint().port!=0)) {
        IFile * ret = createIFileByHook(rfn);           // use daliservix in preference
        if (ret) 
            return ret;             
        while (*filename) {                             // no daliservix so swap '/' for '\' and hope for best
            if (*filename=='/')
                tmplocal.append('\\');
            else
                tmplocal.append(*filename);
            filename++;
        }
        filename =tmplocal.str();
    }   
    return new CWindowsRemoteFile(filename);
#else
#ifdef USE_SAMBA
    if(strncmp(filename, "smb://", 6) == 0)
        return new CSambaRemoteFile(filename);
    if(memcmp(filename, "//", 2) == 0) {
        StringBuffer smbfile("smb:");
        smbfile.append(filename);
        return new CSambaRemoteFile(smbfile.str());
    }
    if(memcmp(filename, "\\\\", 2) == 0) {
        StringBuffer smbfile("smb:");
        int i = 0;
        while(filename[i]) {
            if(filename[i] == '\\')
                smbfile.append('/');
            else
                smbfile.append(filename[i]);
            i++;
        }
        return new CSambaRemoteFile(smbfile.str());
    }
#else
    if (memcmp(filename,"smb://",6)==0)  // don't support samba - try remote
        return createIFile(filename+4);
    IFile * ret = createIFileByHook(rfn);
    if (!ret) 
        throw MakeStringException(-1, "CreateIFile::cannot attach to %s. (remote.so not linked?)", filename);
    return ret;
#endif
    return new CFile(filename);

#endif
}



IFileIOStream * createIOStream(IFileIO * file)
{
    return new CFileIOStream(file);
}



IFileIO * createIORange(IFileIO * io, offset_t header, offset_t length)
{
    return new CFileRangeIO(io, header, length);
}

IFileIOStream * createBufferedIOStream(IFileIO * io, unsigned bufsize)
{
    if (bufsize == (unsigned)-1)
        bufsize = DEFAULT_BUFFER_SIZE;
    return new CBufferedFileIOStream(io, bufsize);
}

IFileIOStream * createBufferedAsyncIOStream(IFileAsyncIO * io, unsigned bufsize)
{
    if (bufsize == (unsigned)-1)
        bufsize = DEFAULT_BUFFER_SIZE*2;
    return new CBufferedAsyncIOStream(io, bufsize);
}

IReadSeq *createReadSeq(IFileIOStream * stream, offset_t offset, size32_t size)
{
    return new CIOStreamReadWriteSeq(stream, offset, size);
}

IWriteSeq *createWriteSeq(IFileIOStream * stream, size32_t size)
{
    return new CIOStreamReadWriteSeq(stream, 0, size);
}



extern jlib_decl offset_t filesize(const char *name)
{
    CFile f(name);
    return f.size();
}

extern jlib_decl offset_t getFreeSpace(const char* name)
{
    offset_t freeBytesToCaller;

#ifdef _WIN32
    offset_t totalBytes;
    offset_t freeBytes;

    int fResult = GetDiskFreeSpaceEx (name,
                                     (PULARGE_INTEGER)&freeBytesToCaller,
                                     (PULARGE_INTEGER)&totalBytes,
                                     (PULARGE_INTEGER)&freeBytes);

    if (fResult == 0)  // error
    {
        return 0;
    }


#elif defined (__linux__)
    struct statfs buf;
    int fResult = statfs(name, &buf);

    if (fResult == -1) // error
    {
        return 0;
    }


    // from "man statfs the def of f_bavail and f_bsize...
    // mult "free blocks avail to non-superuser" by "optimal transfer block size" to get the available size
    
    freeBytesToCaller = (offset_t)buf.f_bavail * buf.f_bsize;
#else
    UNIMPLEMENTED;
#endif

    
    return freeBytesToCaller;
}

extern jlib_decl void createHardLink(const char* fileName, const char* existingFileName)
{
#ifdef _WIN32
    // requirements...need to make sure that the directory already exists
    //                and the 2 directories need to be on the same drive
    if (!CreateHardLink(fileName, existingFileName, NULL))
    {
        LPVOID lpMsgBuf;
        FormatMessage( 
            FORMAT_MESSAGE_ALLOCATE_BUFFER | 
            FORMAT_MESSAGE_FROM_SYSTEM | 
            FORMAT_MESSAGE_IGNORE_INSERTS,
            NULL,
            GetLastError(),
            MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
            (LPTSTR) &lpMsgBuf,
            0,
            NULL 
        );
        StringBuffer err;
        err.appendf("Failed to create log alias %s for %s: %s", fileName, existingFileName, lpMsgBuf);
        LocalFree( lpMsgBuf );

        throw MakeStringException(-1, "createHardLink:: %s.",err.str());

    }
#else
    if (link(existingFileName, fileName) != 0) // error
        throw MakeStringException(-1, "Failed to create log alias %s for %s: error code = %d", fileName, existingFileName, errno);
#endif

}


#if 0
void testDirectory()
{
    //setDefaultUser("administrator", "password");
    Owned<IFile> dir = createIFile("\\test1\\gavin\\home\\base");
    dir->createDirectory();
    Owned<IFile> dir2 = createIFile("\\test1\\gavin\\home\\base2\\");
    dir2->createDirectory();
    dir2->createDirectory();
    Owned<IFile> dir3 = createIFile("c:\\test1\\gavin\\home2\\base");
    dir3->createDirectory();
    Owned<IFile> dir4 = createIFile("\\\\ghalliday\\c$\\test1\\gavin\\home3\\base");
    dir4->createDirectory();
    Owned<IFile> dir5 = createIFile("\\\\192.168.1.3\\d$\\test2\\gavin\\home3\\base");
    dir5->createDirectory();

    StringBuffer x;
    x.clear();
    splitUNCFilename("\\\\127.0.0.1\\gavin\\abc.ext", &x, &x, &x, &x);
    x.clear();
    splitUNCFilename("\\\\127.0.0.1\\gavin\\abc.ext\\etc", &x, &x, &x, &x);
    x.clear();
    splitUNCFilename("\\\\127.0.0.1\\", &x, &x, &x, &x);
}
#endif



// -- RemoteFilename class (file location encapsulation)

//#define _TRACERFN

void RemoteFilename::badFilename(const char * filename)
{
    throw MakeStringException(-1, "Badly formatted file entry %s", filename);
}

bool RemoteFilename::equals(const RemoteFilename & other) const
{   
    if (isNull())
        return other.isNull();
    if (other.isNull())
        return false;
    if (!ep.ipequals(other.ep)) // only use ip for compare
        return false;
    if (isUnixPath()) { // case sensitive
        if (localhead.length()&&other.localhead.length()) {
            if (strcmp(localhead.get(),other.localhead.get())!=0)
                return false;
        }
        else if (sharehead.length()&&other.sharehead.length()) {
            if (strcmp(sharehead.get(),other.sharehead.get())!=0)
                return false;
        }
        else if (sharehead.length()!=other.sharehead.length())
            return false;
        if (strcmp(tailpath.get(),other.tailpath.get())!=0)
            return false;
    }
    else {
        if (localhead.length()&&other.localhead.length()) {
            if (stricmp(localhead.get(),other.localhead.get())!=0)
                return false;
        }
        else if (sharehead.length()&&other.sharehead.length()) {
            if (stricmp(sharehead.get(),other.sharehead.get())!=0)
                return false;
        }
        else if (sharehead.length()!=other.sharehead.length())
            return false;
        if (stricmp(tailpath.get(),other.tailpath.get())!=0)
            return false;
    }
    return true;
}

bool RemoteFilename::isNull() const
{
    return (ep.isNull()||(tailpath.length()==0));
}


void RemoteFilename::clear()
{
    ep.set(NULL, 0);
    localhead.clear();
    sharehead.clear();
    tailpath.clear();
}

void RemoteFilename::serialize(MemoryBuffer & out)
{
    ep.serialize(out);
    out.append(localhead);
    out.append(sharehead);
    out.append(tailpath);
}

void RemoteFilename::deserialize(MemoryBuffer & in)
{
    ep.deserialize(in);
    in.read(localhead);
    in.read(sharehead);
    in.read(tailpath);
}

StringBuffer & RemoteFilename::getTail(StringBuffer &name) const
{
    split(NULL, NULL, &name, &name);
    return name;
}

StringBuffer & RemoteFilename::getPath(StringBuffer & name) const
{
    if (isLocal())
        return getLocalPath(name);
    else
        return getRemotePath(name);
}

bool RemoteFilename::isUnixPath() const // bit arbitrary
{
    if (tailpath.length()!=0) {
        char c = tailpath[0];
        if (c=='/')
            return true;
        if (c=='\\') 
            return false;
    }
    if (sharehead.length()!=0) {
        char c = sharehead[0];
        if (c=='/')
            return true;
        if (c=='\\') 
            return false;
    }
    if (localhead.length()!=0) {
        const char *s=localhead;   
        if (*s=='/')
            return true;
        if ((s[1]==':')&&(s[2]=='/'))
            return false;
        // those are the expected cases, otherwise look for first separator (legacy)
        while (*s) {
            if (*s=='\\')
                return false;
            s++;
            if (*s=='/')
                return true;
        }
    }
#ifdef _WIN32           // assume local on starting machine
    return false;
#else
    return true;
#endif
}

char RemoteFilename::getPathSeparator() const
{
    return isUnixPath()?'/':'\\';
}

StringBuffer & RemoteFilename::getLocalPath(StringBuffer & out) const
{
    if (tailpath.length()!=0) {
        out.append(localhead).append(tailpath);
    }
#ifdef _TRACERFN
    StringBuffer eps;
    PROGLOG("getLocalPath '%s' '%s' '%s' -> '%s'",sharehead.get()?sharehead.get():"NULL",localhead.get()?localhead.get():"NULL",tailpath.get()?tailpath.get():"NULL",out.str());
#endif
    return out;
}

StringBuffer & RemoteFilename::getRemotePath(StringBuffer & out) const
{   // this creates a name that can be used by windows or linux
    // note - no longer loses port
    char c=getPathSeparator();
    out.append(c).append(c);
    ep.getUrlStr(out);
    const char *fn;
    StringBuffer loc;
    if (sharehead.length()) 
        fn = loc.append(sharehead).append(tailpath).str();
    else // try and guess from just tail (may likely fail other than for windows) 
        fn=getLocalPath(loc).str();
    if ((c=='\\')&&(fn[1]==':')) {  // windows \\d$
        out.append((char)tolower(c)).append(*fn).append(getShareChar());
        fn+=2;
    }
    out.append(fn);
#ifdef _TRACERFN
    StringBuffer eps;
    PROGLOG("getRemotePath '%s' '%s' '%s' -> '%s'",sharehead.get()?sharehead.get():"NULL",localhead.get()?localhead.get():"NULL",tailpath.get()?tailpath.get():"NULL",out.str());
#endif
    return out;
}


bool RemoteFilename::isLocal() const
{
    if (ep.port&&(ep.port!=DAFILESRV_PORT))
        return false;  // treat non-dafilesrv port as remote
    return ep.isLocal() || ep.isNull();
}


void RemoteFilename::set(const RemoteFilename & other)
{
    ep.set(other.ep);
    localhead.set(other.localhead);
    sharehead.set(other.sharehead);
    tailpath.set(other.tailpath);

}


void RemoteFilename::setExtension(const char * newext)
{
    const char * dot = NULL;
    const char * start = tailpath;
    const char * cur = start;
    while (*cur)
    {
        if (*cur == '.')
            dot = cur;
        cur++;
    }
    StringBuffer newtail;
    if (dot)
        newtail.append(dot-start,start);
    else
        newtail.append(start);
    if (newext)
    {
        if (newext[0] != '.')
            newtail.append('.');
        newtail.append(newext);
    }
    tailpath.set(newtail);
}


void RemoteFilename::setPath(const SocketEndpoint & _ep, const char * _filename)
{
    const char * filename=_filename;
    StringBuffer full;
    ep.set(_ep);
    localhead.clear();
    sharehead.clear();
    if (filename&&*filename) {
        if (isSpecialPath(filename)) {
            tailpath.set(filename);
            return;
        }
        if (isLocal()&&!isAbsolutePath(filename)) {
            char dir[_MAX_PATH];
            GetCurrentDirectory(sizeof(dir), dir);
            if (*filename==PATHSEPCHAR) {
#ifdef _WIN32
                if (*dir && (dir[1]==':')) 
                    dir[2] = 0;
#endif
                filename++;
            }
            full.append(dir);
            if (full.charAt(full.length()-1) != PATHSEPCHAR)
                full.append(PATHSEPCHAR);
            full.append(filename);
            filename = full.str();
        }
        bool isunix;
        if (filename[0]=='/')
            isunix=true;
        else if (filename[0]=='\\')
            isunix=false;
        else if ((filename[1]==':')&&(filename[2]=='\\'))
            isunix = false;
        else // invalid call really as supposed to be full local path!
#ifdef _WIN32
            isunix = false;
#else
            isunix = true;
#endif
        StringBuffer tmpxlat;
        char sepchar = isunix?'/':'\\';
        char altchar = isunix?'\\':'/';
        // fix mixed separator path 
        if (strchr(filename,altchar)) {
            while (*filename) {
                if (*filename==altchar)
                    tmpxlat.append(sepchar);
                else
                    tmpxlat.append(*filename);
                filename++;
            }
            filename = tmpxlat.str();
        }
        if (isunix) {
            if (filename[0]=='/') {
                const char *tail;
                tail=strchr(filename+1,'/');
                if (tail) {
                    sharehead.set(filename,tail-filename); // we don't know share so guess same as leading dir
                    localhead.set(filename,tail-filename); 
                    filename = tail;
                }
            }
        }
        else { // windows can guess anonymous share
            StringBuffer sharestr;

            if ((filename[1]==':')&&(filename[2]=='\\')) { // this should be always true if true full windows path
                localhead.set(filename,2);
                sharestr.append('\\').append((char)tolower(filename[0])).append(getShareChar());
                filename += 2;
            }
            else if (filename[0]=='\\') {
                const char *tail = strchr(filename+1,'\\');
                if (tail) {
                    sharestr.append(tail-filename,filename);
                    localhead.set(filename,tail-filename);
                    filename = tail;
                }
                else {
                    localhead.set("c:");
                    sharestr.append("\\c").append(getShareChar());
                }
            }   
                        
            sharehead.set(sharestr);
        }
        tailpath.set(filename);
    }
    else
        tailpath.clear();
#ifdef _TRACERFN
    StringBuffer eps;
    PROGLOG("setPath (%s,%s) -> '%s' '%s' '%s'",ep.getUrlStr(eps).str(),_filename?_filename:"NULL",sharehead.get()?sharehead.get():"NULL",localhead.get()?localhead.get():"NULL",tailpath.get()?tailpath.get():"NULL");
#endif
}

void RemoteFilename::setRemotePath(const char * _url,const char *localpath)
{
    // url should be full (share) path including ep
    const char *url=_url;
    // if ep not included then assume local (bit weird though)
    char sep = url?url[0]:0;
    if (isPathSepChar(sep)&&(sep==url[1])) {
        url+=2;
        const char *end = findPathSepChar(url);
        if (end) {
            StringBuffer eps(end-url,url);
            ep.set(eps.str());
            url = end;
        }
        else {
            ep.set(NULL,0);
            url--; // don't know what is going on!
        }
        if (isPathSepChar(*url)||!*url)
            sep = *url;
    }
    else
        ep.setLocalHost(0);
    if (localpath&&*localpath) 
        setPath(ep,localpath);
    else {
        localhead.clear();
        sharehead.clear();
        tailpath.clear();
    }
    if (sep&&*url) {
        // url should point to the share now
        const char *tail=findPathSepChar(url+1); 
        if (tail) { // hopefully must be!
            sharehead.set(url,tail-url);
            url = tail;
        }
        if (localhead.length()==0) { // we don't know so guess
            if (sharehead.length()!=0) {
                const char *share=sharehead.get();
                if (sep=='\\') {
                    StringBuffer locstr;
                    if (sharehead.length()>2) {
                        if (isShareChar(share[2]))  {
                            locstr.append(share[1]).append(':');
                            share+=3;
                        }
                        else  // we haven't a clue!
                            locstr.append("c:");
                    }
                    else if (sharehead[1]!='$')  // data format
                        locstr.append("c:");
                    locstr.append(share);
                    localhead.set(locstr);
                }
                else { // we haven't a clue so assume same as share
                    localhead.set(sharehead);
                }
            }
        }

    }
    if (tailpath.length()==0)
        tailpath.set(url);
#ifdef _TRACERFN
    StringBuffer eps;
    PROGLOG("setRemotePath ('%s','%s') -> '%s' '%s' '%s'",_url,localpath?localpath:"NULL",sharehead.get()?sharehead.get():"NULL",localhead.get()?localhead.get():"NULL",tailpath.get()?tailpath.get():"NULL");
#endif
}


void RemoteFilename::setLocalPath(const char *filename)
{
    SocketEndpoint localEP;
    localEP.setLocalHost(0);
    setPath(localEP, filename);
}


void RemoteFilename::split(StringBuffer * drive, StringBuffer * path, StringBuffer * tail, StringBuffer * ext) const
{
    StringBuffer localname;
    const char *s = getLocalPath(localname).str();
    char sep;
    if (isUnixPath())
        sep = '/';
    else {
        sep = '\\';
        if (s[1]==':') {
            if (drive)
                drive->append(2,s);
            s+=2;
        }
    }
    const char *t=NULL;
    const char *e=s;
    while (*e) {
        if (*e==sep)
            t = e+1;
        e++;
    }
    if (t) {
        if (path)
            path->append(t-s, s);
        s=t;
    }
    if (!tail&&!ext)
        return;
    t = NULL;
    e=s;
    while (*e) {
        if (*e=='.')        // NB final extension
            t = e;
        e++;
    }
    if (t) {
        if (tail)
            tail->append(t-s,s);
        if (ext)
            ext->append(e-t,t);
    }
    else if (tail)
        tail->append(e-s,s);
}

void RemoteMultiFilename::append(const char *mpath,const char *defaultdir)
{
    StringArray paths;
    expand(mpath, paths);
    StringBuffer fullpath;
    StringBuffer deftmp;
    if (paths.ordinality()&&(defaultdir==NULL)&&isAbsolutePath(paths.item(0))) {
        splitDirTail(paths.item(0),deftmp);
        defaultdir = deftmp.str();
    }
    ForEachItemIn(i,paths) {
        const char *filename = paths.item(i);
        RemoteFilename rfn;
        if (isPathSepChar(*filename)&&isPathSepChar(filename[1]))  // full URL
            rfn.setRemotePath(filename);
        else {
            if (defaultdir&&!isAbsolutePath(filename)) 
                filename = addPathSepChar(fullpath.clear().append(defaultdir)).append(filename).str();
            rfn.setPath(ep,filename);
        }
        append(rfn);
    }
}

void RemoteMultiFilename::append(const RemoteFilename &inrfn)
{
    RemoteFilename rfn;
    rfn.set(inrfn);
    if (ep.isNull())
        ep = rfn.queryEndpoint();
    else if (rfn.queryIP().isNull()) {
        rfn.setEp(ep);
    }
    else if (!rfn.queryIP().ipequals(ep)) {
        StringBuffer path;
        rfn.getRemotePath(path);
        throw MakeStringException(-1, "Component file IP does not match: %s", path.str());          
    }
    RemoteFilenameArray::append(rfn);           
}

void RemoteMultiFilename::deserialize(MemoryBuffer & in)
{
    clear();
    ep.deserialize(in);
    unsigned n;
    in.read(n);
    StringBuffer last;
    StringBuffer filename;
    RemoteFilename rfn;
    for (unsigned i=0;i<n;i++) {
        byte l;
        in.read(l);
        filename.clear();
        if (l) 
            filename.append((size32_t)l,last.str());
        StringAttr s;
        in.read(s);
        filename.append(s);
        rfn.setPath(ep,filename.str());
        RemoteFilenameArray::append(rfn);           
        last.swapWith(filename);
    }
}

void RemoteMultiFilename::serialize(MemoryBuffer & out)
{
    ep.serialize(out);
    unsigned n=ordinality();
    out.append(n);
    // do simple compression
    StringBuffer last;
    StringBuffer filename;
    for (unsigned i=0;i<n;i++) {
        item(i).getLocalPath(filename.clear());
        const char *s1 = last.str();
        const char *s2 = filename.str();
        byte l=0;
        while ((l<255)&&*s1&&*s2&&(*s1==*s2)) {
            s1++;
            s2++;
            l++;
        }
        out.append(l);
        out.append(s2);
        last.swapWith(filename);
    }
}

bool RemoteMultiFilename::isWild(unsigned idx) const
{
    if (idx==(unsigned)-1) {
        ForEachItem(i)
            if (isWild(i))
                return true;
    }
    else {
        StringBuffer s;
        item(idx).getTail(s);
        if (containsFileWildcard(s.str()))
            return true;
    }
    return false;
}

void RemoteMultiFilename::expandWild() 
{
    bool anywild = false;
    BoolArray iswild; 
    ForEachItem(i1) {
        if (isWild(i1)) {
            anywild = true;
            iswild.append(true);
        }
        else
            iswild.append(false);
    }
    if (!anywild)
        return;         // nothing to do
    // first cache old values (bit long winded but want to preserve order)
    RemoteFilenameArray tmpa;
    Int64Array tmpsz;
    ForEachItem(i2) {
        RemoteFilename rfn(item(i2));
        tmpa.append(rfn);
        if (i2<sizescache.ordinality())
            tmpsz.append(sizescache.item(i2));
        else
            tmpsz.append(-1);
    }
    RemoteFilenameArray::kill(); 
    sizescache.kill();
    ForEachItemIn(i3,tmpa) {
        RemoteFilename rfn(tmpa.item(i3));
        if (iswild.item(i3)) {
            StringBuffer name;
            rfn.getLocalPath(name);
            const char *s=name.str();
            const char *t=s;
            loop {
                const char *sep=findPathSepChar(t);
                if (!sep)
                    break;
                t = sep+1;
            }
            StringAttr tail(t);
            name.setLength(t-s);
            rfn.setPath(rfn.queryEndpoint(),name);
            Owned<IFile> dir = createIFile(rfn);
            Owned<IDirectoryIterator> iter = dir->directoryFiles(tail.get());
            ForEach(*iter) {
                append(iter->query().queryFilename());
                sizescache.append(iter->getFileSize());
            }
        }
        else {
            append(rfn);
            sizescache.append(tmpsz.item(i3));
        }
    }
}

offset_t RemoteMultiFilename::getSize(unsigned i)
{
    __int64 ret = (i<sizescache.ordinality())?sizescache.item(i):-1;
    if (ret==-1) {
        RemoteFilename rfn(item(i));
        Owned<IFile> file = createIFile(rfn);
        ret = file->size();
    }
    return (offset_t)ret;
}


void RemoteMultiFilename::setIp(const IpAddress & ip)
{
    ep.ipset(ip);
    ForEachItem(i)
        item(i).setIp(ip);
}

void RemoteMultiFilename::setEp(const SocketEndpoint & _ep)
{
    ep.set(_ep);
    ForEachItem(i)
        item(i).setEp(_ep);
}

void RemoteMultiFilename::setPort(unsigned short port)
{
    ep.port = port;
    ForEachItem(i)
        item(i).setPort(port);
}

void RemoteMultiFilename::set(const RemoteMultiFilename & other)
{
    clear();
    ep.set(other.ep);
    ForEachItemIn(i,other) {
        append(other.item(i));
        if (i<other.sizescache.ordinality())
            sizescache.append(other.sizescache.item(i));
    }
}


bool RemoteMultiFilename::equals(const RemoteMultiFilename & other)
{
    if (!ep.equals(other.ep))
        return false;
    if (ordinality()!=other.ordinality())
        return false;
    ForEachItem(i) 
        if (!item(i).equals(other.item(i)))
            return false;
    return true;
}


void RemoteMultiFilename::expand(const char *mpath, StringArray &array)
{
    StringBuffer path;
    StringBuffer fullpath;
    loop {
        while (isspace(*mpath))
            mpath++;
        if (!*mpath)
            break;
        bool inquote=false;
        while (*mpath) {
            if (*mpath=='"') {
                mpath++;
                if (inquote) {
                    if (*mpath!='"') {
                        inquote = false;
                        continue;
                    }
                }
                else {
                    inquote = true;
                    continue;
                }
            }
            if ((*mpath==',')&&!inquote) {
                mpath++;
                break;
            }
            path.append(*mpath);
            mpath++;
        }
        path.clip();
        if (path.length()) {
            array.append(path.str());
            path.clear();
        }
    }
}

void RemoteMultiFilename::tostr(StringArray &array,StringBuffer &out)
{
    ForEachItemIn(i,array) {
        const char *s = array.item(i);
        if (!s||!*s)
            continue;
        if (i!=0)
            out.append(',');
        bool needquote=false;
        for (const char *e=s;*e;e++)
            if (isspace(*e)||(*e==',')) {
                needquote = true;
                break;
            }
        if (needquote)
            out.append('"');
        out.append(s);
        if (needquote)
            out.append('"');
    }
}

//===================================================================================================

static IArrayOf<IFileCreateHook> hooks;
static CriticalSection hooksect;

void addIFileCreateHook(IFileCreateHook *hook)
{
    if (hook) {
        hook->Link();
        CriticalBlock block(hooksect);
        hooks.append(*hook);
    }
}

void removeIFileCreateHook(IFileCreateHook *hook)
{
    CriticalBlock block(hooksect);
    hooks.zap(*hook);
}


static IFile *createIFileByHook(const RemoteFilename & filename)
{
    CriticalBlock block(hooksect); // this may be a problem (serializing opens)
    ForEachItemIn(i,hooks) {
        IFile * ret = hooks.item(i).createIFile(filename);
        if (ret)
            return ret;
    }
    return NULL;
}


IFile * createIFile(const RemoteFilename & filename)
{
    IFile * ret = createIFileByHook(filename);
    if (ret)
        return ret;
    StringBuffer name;
    return createIFile(getLocalOrRemoteName(name,filename).str());
}

StringBuffer &makeAbsolutePath(const char *relpath,StringBuffer &out)
{
    if (isPathSepChar(relpath[0])&&(relpath[0]==relpath[1]))
        return out.append(relpath); // if remote then already should be absolute
#ifdef _WIN32
    char path[256];
    path[0] = 0;
    char *filepart;
    GetFullPathName(relpath, sizeof(path), path, &filepart);
#else
    char path[PATH_MAX+1];
    path[0] = 0;
    realpath(relpath,path);
#endif
    return out.append(path);
}

const char *splitRelativePath(const char *full,const char *basedir,StringBuffer &reldir)
{
    if (basedir&&*basedir) {
        size32_t bl = strlen(basedir);
        if (isPathSepChar(basedir[bl-1]))
            bl--;
        if ((memicmp(full,basedir,bl)==0)&&isPathSepChar(full[bl]))
            full += bl+1;
    }
    const char *t = full;
    loop {
        const char *n = findPathSepChar(t);
        if (!n) 
            break;
        t = n+1;
    }
    if (t!=full) 
        reldir.append(t-full,full);
    return t;
}

const char *splitDirMultiTail(const char *multipath,StringBuffer &dir,StringBuffer &tail)
{
    // the first directory is the significant one
    // others only removed if same
    dir.clear();
    StringArray files;
    RemoteMultiFilename::expand(multipath,files);
    StringBuffer reldir;
    ForEachItemIn(i,files) {
        const char *s = files.item(i);
        if (i==0) {
            if (isAbsolutePath(s)) {
                StringAttr tail(splitDirTail(s,dir));
                if (dir.length())
                    files.replace(tail,i);
            }
        }
        else if (dir.length()) {
            s= splitRelativePath(s,dir.str(),reldir.clear());
            if (reldir.length()) {
                reldir.append(s);
                files.replace(reldir.str(),i);
            }
        }
    }
    RemoteMultiFilename::tostr(files,tail);
    return tail.str();
}

StringBuffer &mergeDirMultiTail(const char *dir,const char *tail, StringBuffer &multipath)
{
    StringArray files;
    RemoteMultiFilename::expand(tail,files);
    StringBuffer reldir;
    if (dir && *dir) {
        ForEachItemIn(i,files) {
            const char *s = files.item(i);
            if (!isAbsolutePath(s)) {
                reldir.clear().append(dir);
                addPathSepChar(reldir).append(s);
                files.replace(reldir.str(),i);
            }
        }
    }
    RemoteMultiFilename::tostr(files,multipath);
    return multipath;

}

StringBuffer &removeRelativeMultiPath(const char *full,const char *reldir,StringBuffer &res)
{
    StringArray files;
    RemoteMultiFilename::expand(full,files);
    StringBuffer tmp1;
    StringBuffer tmp2;
    StringBuffer dir;
    ForEachItemIn(i,files) {
        const char *s = files.item(i);
        if (isAbsolutePath(s)) {
            if (!dir.length()) 
                splitDirTail(s,dir);
        }
        else if (dir.length()) {
            tmp1.clear().append(dir);
            addPathSepChar(tmp1).append(s);
            s = tmp1.str();
        }
        s = splitRelativePath(s,reldir,tmp2.clear());
        tmp2.append(s);
        files.replace(tmp2.str(),i);
    }
    RemoteMultiFilename::tostr(files,res);
    return res;
}
// removes basedir if matches, returns relative multipath


//===================================================================================================

ExtractedBlobInfo::ExtractedBlobInfo(const char * _filename, offset_t _length, offset_t _offset)
{
    filename.set(_filename);
    length = _length;
    offset = _offset;
}

void ExtractedBlobInfo::serialize(MemoryBuffer & buffer)
{
    ::serialize(buffer, filename.get());
    buffer.append(length).append(offset);
}

void ExtractedBlobInfo::deserialize(MemoryBuffer & buffer)
{
    ::deserialize(buffer, filename);
    buffer.read(length).read(offset);
}

//----------------------------------------------------------------------------

#define DFTERR_InvalidSplitPrefixFormat         8091
#define DFTERR_InvalidSplitPrefixFormat_Text    "Cannot process file %s using the splitprefix supplied"

static void * readLength(MemoryBuffer & buffer, IFileIOStream * in, size_t len, const char * filenameText)
{
    void * ptr = buffer.clear().reserve(len);
    if (in->read(len, ptr) != len)
        throwError1(DFTERR_InvalidSplitPrefixFormat, filenameText);
    return ptr;
}

void extractBlobElements(const char * prefix, const RemoteFilename &filename, ExtractedBlobArray & extracted)
{
    StringBuffer filenameText;
    filename.getPath(filenameText);
    Owned<IFile> file = createIFile(filename);
    Owned<IFileIO> inIO = file->open(IFOread);
    if (!inIO)
        throw MakeStringException(-1, "extractBlobElements: file '%s' not found", filenameText.str());
    Owned<IFileIOStream> in = createIOStream(inIO);

    MemoryBuffer buffer;
    offset_t endOffset = in->size();
    while (in->tell() != endOffset)
    {
        StringAttr blobFilename;
        offset_t blobLength = (offset_t)-1;
        const char * finger = prefix;
        while (finger)
        {
            StringAttr command;
            const char * comma = strchr(finger, ',');
            if (comma)
            {
                command.set(finger, comma-finger);
                finger = comma+1;
            }
            else
            {
                command.set(finger);
                finger = NULL;
            }

            command.toUpperCase();
            if (memcmp(command, "FILENAME", 8) == 0)
            {
                if (command[8] == ':')
                {
                    unsigned maxLen = atoi(command+9);
                    const char * nameptr = (const char *)readLength(buffer, in, maxLen, filenameText.str());
                    blobFilename.set(nameptr, maxLen);
                }
                else
                {
                    unsigned * lenptr = (unsigned *)readLength(buffer, in, sizeof(unsigned), filenameText.str());
#if __BYTE_ORDER != __LITTLE_ENDIAN
                    _rev(sizeof(*lenptr), lenptr);
#endif
                    unsigned filenamelen = *lenptr;
                    const char * nameptr = (const char *)readLength(buffer, in, filenamelen, filenameText.str());
                    blobFilename.set(nameptr, filenamelen);
                }
            }
            else if ((memcmp(command, "FILESIZE", 8) == 0) || (command.length() == 2))
            {
                const char * format = command;
                if (memcmp(format, "FILESIZE", 8) == 0)
                {
                    if (format[8] == ':')
                        format = format+9;
                    else
                        format = "L4";
                }

                bool bigEndian;
                char c = format[0];
                if (c == 'B')
                    bigEndian = true;
                else if (c == 'L')
                    bigEndian = false;
                else
                    throwError1(DFTERR_InvalidSplitPrefixFormat, format);
                c = format[1];
                if ((c <= '0') || (c > '8'))
                    throwError1(DFTERR_InvalidSplitPrefixFormat, format);

                unsigned length = (c - '0');
                byte * lenptr = (byte *)readLength(buffer, in, length, filenameText.str());
                if (!bigEndian)
                    _rev(length, lenptr);

                blobLength = 0;
                for (unsigned i=0; i<length; i++)
                {
                    blobLength = (blobLength << 8) | lenptr[i];
                }
            }
            else if (memcmp(command, "SKIP:", 5) == 0)
            {
                unsigned skipLen = atoi(command+5);
                in->seek(in->tell()+skipLen, IFSbegin);
            }
            else if (memcmp(command, "SEQ:", 4) == 0)
            {
                unsigned skipLen = atoi(command+4);
                in->seek(in->tell()+skipLen, IFSbegin);
            }
            else
                throwError1(DFTERR_InvalidSplitPrefixFormat, command.get());
        }

        if ((blobLength == (offset_t)-1) || !blobFilename.get())
            throwError1(DFTERR_InvalidSplitPrefixFormat, filenameText.str());

        offset_t blobOffset = in->tell();
        extracted.append(* new ExtractedBlobInfo(blobFilename, blobLength, blobOffset));
        in->seek(blobOffset + blobLength, IFSbegin);
    }
}

bool mountDrive(const char *drv,const RemoteFilename &rfn)
{
#ifdef _WIN32
    return false;
#else
    unmountDrive(drv);
    localCreateDirectory(drv);
    int ret;
    for (unsigned vtry=0;vtry<2;vtry++) {
        StringBuffer cmd;
        cmd.append("mount ");
        rfn.queryIP().getIpText(cmd);
        cmd.append(':');
        rfn.getLocalPath(cmd);
        cmd.append(' ').append(drv).append(" -t nfs ");
        if (vtry==0)
            cmd.append("-o nfsvers=v3 "); // prefer v3
        cmd.append("2> /dev/null");
        ret = system(cmd.str());
        if (ret==0)
            break;
    }
    return (ret==0);
#endif

}

bool unmountDrive(const char *drv)
{
#ifdef _WIN32
    return false;
#else
    StringBuffer cmd;
    cmd.append("umount ").append(drv).append(" 2> /dev/null");
    int ret = system(cmd.str());
    return (ret==0);
#endif

}

IFileIO *createUniqueFile(const char *dir, const char *prefix, StringBuffer &filename)
{
    CDateTime dt;
    dt.setNow();
    unsigned t = (unsigned)dt.getSimple();
    if (dir)
    {
        filename.append(dir);
        addPathSepChar(filename);
    }
    if (prefix && *prefix)
        filename.append(prefix);
    else
        filename.append("uniq");
    filename.appendf("_%"I64F"x.%x.%x.tmp", (__int64)GetCurrentThreadId(), (unsigned)GetCurrentProcessId(), t);
    OwnedIFile iFile = createIFile(filename.str());
    IFileIO *iFileIO = NULL;
    unsigned attempts = 5; // max attempts
    loop
    {
        if (!iFile->exists())
        {
            try { return iFile->openShared(IFOcreate, IFSHnone); } // NB: could be null if path not found
            catch (IException *e)
            {
                EXCLOG(e, "createUniqueFile");
                e->Release();
            }
        }
        if (0 == --attempts)
            break;
        t += getRandom();
        filename.clear().appendf("uniq_%"I64F"x.%x.%x.tmp", (__int64)GetCurrentThreadId(), (unsigned)GetCurrentProcessId(), t);
        iFile.setown(createIFile(filename.str()));
    }
    return NULL;
}

unsigned sortDirectory( CIArrayOf<CDirectoryEntry> &sortedfiles,
                        IDirectoryIterator &iter, 
                        SortDirectoryMode mode,
                        bool rev,
                        bool includedirs
                      ) 
{
    sortedfiles.kill();
    StringBuffer name;
    ForEach(iter) {
        if (!iter.isDir()||includedirs) 
            sortedfiles.append(*new CDirectoryEntry(iter));
    }
    if (mode!=SD_nosort) {
        struct icmp: implements ICompare
        {
            SortDirectoryMode mode;
            bool rev;
            int docompare(const void *l,const void *r) const
            {
                int ret=0;
                const CDirectoryEntry *dl = (const CDirectoryEntry *)l;
                const CDirectoryEntry *dr = (const CDirectoryEntry *)r;
                switch (mode) {
                case SD_byname:
                    ret = strcmp(dl->name,dr->name);
                    break;
                case SD_bynameNC:
                    ret = stricmp(dl->name,dr->name);
                    break;
                case SD_bydate:
                    ret = dl->modifiedTime.compare(dr->modifiedTime);
                    break;
                case SD_bysize:
                    ret = (dl->size>dr->size)?1:((dl->size<dr->size)?-1:0);
                    break;
                }
                if (rev)
                    ret = -ret;
                return ret;
            }
        } cmp;
        cmp.mode = mode;
        cmp.rev = rev;
        qsortvec((void **)sortedfiles.getArray(), sortedfiles.ordinality(), cmp);
    }
    return sortedfiles.ordinality();
}


class CReplicatedFile : public CInterface, implements IReplicatedFile
{
    RemoteFilenameArray copies;
public:
    IMPLEMENT_IINTERFACE;

    RemoteFilenameArray &queryCopies()
    {
        return copies;
    }

    
    IFile *open()
    {
        StringBuffer locations;
        Owned<IException> exc;
        ForEachItemIn(copy,copies) {
            RemoteFilename &rfn = copies.item(copy);
            try {
                OwnedIFile iFile = createIFile(rfn);
                if (iFile->exists())
                    return iFile.getClear();
                if (locations.length())
                    locations.append(", ");
                rfn.getRemotePath(locations);
            }
            catch(IException *e) {
                EXCLOG(e,"CReplicatedFile::open");
                if (exc)
                    e->Release();
                else
                    exc.setown(e);
            }
        }
        if (exc.get())
            throw exc.getClear();
        throw MakeStringException(0, "%s: Failed to open part file at any of the following locations: ", locations.str());
    }
};

IReplicatedFile *createReplicatedFile()
{
    return new CReplicatedFile;
}


// ---------------------------------------------------------------------------------

class CSerialStreamBase : public CInterface, implements ISerialStream
{
private:
    size32_t bufsize;
    size32_t bufpos;
    size32_t bufmax;
    offset_t bufbase;
    offset_t endpos; // -1 if not known
    MemoryAttr ma;
    byte *buf;
    bool eoinput;
    IFileSerialStreamCallback *tally;

    inline size32_t doread(offset_t pos, size32_t max_size, void *ptr)
    {
        if (endpos!=(offset_t)-1) {
            if (pos>=endpos)
                return 0;
            if (endpos-pos<max_size)
                max_size = (size32_t)(endpos-pos);
        }
        size32_t size_read = rawread(pos, max_size, ptr);
        if (tally)
            tally->process(pos,size_read,ptr);
        return size_read;
    }

    const void * dopeek(size32_t sz, size32_t &got)
    {
        loop
        {
            size32_t left = bufmax-bufpos;
            got = left;
            if (left>=sz) 
                return buf+bufpos;
            if (eoinput) 
                return left?(buf+bufpos):NULL;
            size32_t reqsz = sz+bufsize;  // NB not sz-left as want some slack
            if (ma.length()<reqsz) {
                MemoryAttr ma2;
                void *nb = ma2.allocate(reqsz);
                memcpy(nb,buf+bufpos,left);
                ma.setOwn(reqsz,ma2.detach());
                buf = (byte *)nb;
            }
            else 
                memmove(buf,buf+bufpos,left);
            bufbase += bufpos;
            size32_t rd = doread(bufbase+left,bufsize,buf+left);
            if (!rd) 
                eoinput = true;
            bufmax = rd+left;
            bufpos = 0;
        }
    }

protected:
    virtual size32_t rawread(offset_t pos, size32_t max_size, void *ptr) = 0;

public:
    IMPLEMENT_IINTERFACE;
    CSerialStreamBase(offset_t _offset, offset_t _len, size32_t _bufsize, IFileSerialStreamCallback *_tally)
    {
        tally = _tally;
        bufsize = _bufsize;
        if (bufsize==(size32_t)-1)
            bufsize = DEFAULT_STREAM_BUFFER_SIZE; 
        if (bufsize<4096)
            bufsize = 4096;
        else
            bufsize = ((bufsize+4095)/4096)*4096;
        buf = (byte *)ma.allocate(bufsize+4096); // 4K initial slack
        bufpos = 0;
        bufmax = 0;
        bufbase = _offset;
        if (_len==(offset_t)-1)
            endpos = (offset_t)-1;
        else
            endpos = _offset+_len;
        eoinput = (_len==0);
    }

    void reset(offset_t _offset, offset_t _len)
    {
        bufpos = 0;
        bufmax = 0;
        bufbase = _offset;
        if (_len==(offset_t)-1)
            endpos = (offset_t)-1;
        else
            endpos = _offset+_len;
        eoinput = (_len==0);
    }

    const void *peek(size32_t sz,size32_t &got)
    {
        return dopeek(sz, got);
    }

    void get(size32_t len, void * ptr)
    {
        size32_t cpy = bufmax-bufpos;
        if (cpy>len)
            cpy = len;
        memcpy(ptr,(const byte *)buf+bufpos,cpy);
        len -= cpy;
        if (len==0) {
            bufpos += cpy;
            return;
        }
        bufbase += bufmax;
        bufpos = 0;
        bufmax = 0;
        size32_t rd = 0;
        if (!eoinput) {
            ptr = (byte *)ptr+cpy;
            if (len>=bufsize) {
                size32_t tord = (len/bufsize)*bufsize;
                rd =  doread(bufbase,tord,ptr); // copy directly if large
                bufbase += rd;
                if (rd!=tord) {
                    eoinput = true;
                    PrintStackReport();
                    ERRLOG("CFileSerialStream::get read past end of stream.1 (%u,%u) %s",rd,tord,eoinput?"eoinput":"");
                    throw MakeStringException(-1,"CFileSerialStream::get read past end of stream");
                }
                cpy += rd;
                len -= rd;
                if (!len) 
                    return;
                ptr = (byte *)ptr+rd;
            }
            const void *p = dopeek(len,rd);
            if (len<=rd) {
                memcpy(ptr,p,len);
                bufpos += len;
                return;
            }
        }
        PrintStackReport();
        ERRLOG("CFileSerialStream::get read past end of stream.2 (%u,%u) %s",len,rd,eoinput?"eoinput":"");
        throw MakeStringException(-1,"CFileSerialStream::get read past end of stream");
    }

    bool eos()
    {
        if (bufmax-bufpos)
            return false;
        size32_t rd;
        return dopeek(1,rd)==NULL;
    }

    void skip(size32_t len)
    {
        size32_t left = bufmax-bufpos;
        if (left>=len) {
            bufpos += len;
            return;
        }
        len -= left;
        bufbase += bufmax;
        bufpos = 0;
        bufmax = 0;
        if (!eoinput) {
            while (len>=bufsize) {
                size32_t rd;
                if (tally) {
                    rd = doread(bufbase,bufsize,buf);
                    if (rd!=bufsize) {
                        eoinput = true;
                        throw MakeStringException(-1,"CFileSerialStream::skip read past end of stream");
                    }
                }
                else {
                    rd = (len/bufsize)*bufsize;
                    //rd=doskip(bufbase,bufsize,buf); to cope with reading from sockets etc?
                }
                bufbase += rd;
                len -= bufsize;
            }
            if (len==0)
                return;
            size32_t got;
            dopeek(len,got);
            if (len<=got) {
                bufpos += got;
                return;
            }
        }
        throw MakeStringException(-1,"CFileSerialStream::skip read past end of stream");
    }

    offset_t tell()
    {
        return bufbase+bufpos;
    }

};



class CFileSerialStream: public CSerialStreamBase
{
    Linked<IFileIO> fileio;

    virtual size32_t rawread(offset_t pos, size32_t max_size, void *ptr)  
    {
        return fileio->read(pos,max_size,ptr);
    }

public:
    CFileSerialStream(IFileIO *_fileio,offset_t _offset, offset_t _len, size32_t _bufsize, IFileSerialStreamCallback *_tally)
      : CSerialStreamBase(_offset, _len, _bufsize, _tally), fileio(_fileio)
    {
    }
};


ISerialStream *createFileSerialStream(IFileIO *fileio,offset_t ofs, offset_t flen, size32_t bufsize,IFileSerialStreamCallback *callback)
{
    if (!fileio)
        return NULL;
    return new CFileSerialStream(fileio,ofs,flen,bufsize,callback);
}


class CIoSerialStream: public CSerialStreamBase
{
    Linked<IFileIOStream> io;
    offset_t lastpos;


    virtual size32_t rawread(offset_t pos, size32_t max_size, void *ptr)  
    {
        if (lastpos!=pos)
            throw MakeStringException(-1,"CIoSerialStream: non-sequential read (%"I64F"d,%"I64F"d)",lastpos,pos);
        size32_t rd = io->read(max_size,ptr);
        lastpos = pos+rd;
        return rd;
    }

public:
    CIoSerialStream(IFileIOStream * _io,offset_t _offset, size32_t _bufsize, IFileSerialStreamCallback *_tally)
      : CSerialStreamBase(_offset, (offset_t)-1, _bufsize, _tally), io(_io)
    {
        lastpos = _offset;
    }
};


ISerialStream *createFileSerialStream(IFileIOStream *io,size32_t bufsize,IFileSerialStreamCallback *callback)
{
    if (!io)
        return NULL;
    return new CIoSerialStream(io,0,bufsize,callback);
}


class CSocketSerialStream: public CSerialStreamBase
{
    Linked<ISocket> socket;
    unsigned timeout;
    offset_t lastpos;

    virtual size32_t rawread(offset_t pos, size32_t max_size, void *ptr)  
    {
        if (lastpos!=pos)
            throw MakeStringException(-1,"CSocketSerialStream: non-sequential read (%"I64F"d,%"I64F"d)",lastpos,pos);
        size32_t size_read;
        socket->readtms(ptr, 0, max_size, size_read, timeout); 
        lastpos = pos+size_read;
        return size_read;
    }

public:
    CSocketSerialStream(ISocket * _socket, unsigned _timeout, offset_t _offset, size32_t _bufsize, IFileSerialStreamCallback *_tally)
      : CSerialStreamBase(_offset, (offset_t)-1, _bufsize, _tally), socket(_socket), timeout(_timeout)
    {
        lastpos = _offset;
    }
};


ISerialStream *createSocketSerialStream(ISocket * socket, unsigned timeoutms, size32_t bufsize, IFileSerialStreamCallback *callback)
{
    if (!socket)
        return NULL;
    return new CSocketSerialStream(socket,timeoutms,0,bufsize,callback);
}


class CSimpleReadSerialStream: public CSerialStreamBase
{
    Linked<ISimpleReadStream> input;
    offset_t lastpos;

    virtual size32_t rawread(offset_t pos, size32_t max_size, void *ptr)  
    {
        if (lastpos!=pos)
            throw MakeStringException(-1,"CSimpleReadSerialStream: non-sequential read (%"I64F"d,%"I64F"d)",lastpos,pos);
        size32_t rd = input->read(max_size, ptr);
        lastpos += rd;
        return rd;
    }

public:
    CSimpleReadSerialStream(ISimpleReadStream * _input, offset_t _offset, size32_t _bufsize, IFileSerialStreamCallback *_tally)
      : CSerialStreamBase(_offset, (offset_t)-1, _bufsize, _tally), input(_input)
    {
        lastpos = _offset;
    }

    void reset(offset_t _ofs, offset_t _len)
    {
        // assume knows what doing
        lastpos = _ofs;
        CSerialStreamBase::reset(_ofs,_len);
    }

};


ISerialStream *createSimpleSerialStream(ISimpleReadStream * input, size32_t bufsize, IFileSerialStreamCallback *callback)
{
    if (!input)
        return NULL;
    return new CSimpleReadSerialStream(input,0,bufsize,callback);
}


class CMemoryMappedSerialStream: public CInterface, implements ISerialStream
{
    Linked<IMemoryMappedFile> mmfile;
    const byte *mmbase;
    memsize_t mmsize;
    memsize_t mmofs;
    bool eoinput;
    IFileSerialStreamCallback *tally;

public:
    IMPLEMENT_IINTERFACE;
    CMemoryMappedSerialStream(IMemoryMappedFile *_mmfile, offset_t ofs, offset_t flen, IFileSerialStreamCallback *_tally)
        : mmfile(_mmfile)
    {
        tally = _tally;
        offset_t fs = mmfile->fileSize();
        if ((memsize_t)fs!=fs)
            throw MakeStringException(-1,"CMemoryMappedSerialStream file too big to be mapped");
        if ((flen!=(offset_t)-1)&&(fs>flen))
            fs = flen;
        mmsize = (memsize_t)fs;
        mmofs = (memsize_t)((ofs<fs)?ofs:fs);
        mmbase = (const byte *)mmfile->base();
        eoinput = false;
    }

    void reset(offset_t _ofs, offset_t _len)
    {
        offset_t fs = mmfile->fileSize();
        if ((_len!=(offset_t)-1)&&(fs>_len))
            fs = _len;
        mmsize = (memsize_t)fs;
        mmofs = (memsize_t)((_ofs<fs)?_ofs:fs);
        mmsize = (memsize_t)fs;
    }

    CMemoryMappedSerialStream(const void *buf, memsize_t len, IFileSerialStreamCallback *_tally)
    {
        tally = _tally;
        mmsize = len;
        mmofs = 0;
        mmbase = (const byte *)buf;
        eoinput = false;
    }

    const void *peek(size32_t sz,size32_t &got)
    {
        memsize_t left = mmsize-mmofs;
        if (sz>left)
            sz = (size32_t)left;
        else if (left>=UINT_MAX) 
            got = UINT_MAX-1;
        else
            got = (size32_t)left;
        return mmbase+mmofs;
    }

    void get(size32_t len, void * ptr)
    {
        memsize_t left = mmsize-mmofs;
        if (len>left) {
            PrintStackReport();
            ERRLOG("CFileSerialStream::get read past end of stream.3 (%u,%u)",(unsigned)len,(unsigned)left);
            throw MakeStringException(-1,"CMemoryMappedSerialStream::get read past end of stream (%u,%u)",(unsigned)len,(unsigned)left);
        }
        if (tally)
            tally->process(mmofs,len,mmbase+mmofs);
        memcpy(ptr,mmbase+mmofs,len);
        mmofs += len;
    }

    bool eos()
    {
        return (mmsize<=mmofs);
    }

    void skip(size32_t len)
    {
        memsize_t left = mmsize-mmofs;
        if (len>left)
            throw MakeStringException(-1,"CMemoryMappedSerialStream::skip read past end of stream (%u,%u)",(unsigned)len,(unsigned)left);
        if (tally)
            tally->process(mmofs,len,mmbase+mmofs);
        mmofs += len;
    }

    offset_t tell()
    {
        return mmofs;
    }

    virtual void reset(offset_t _offset)
    {
        mmofs = (memsize_t)((_offset<mmsize)?_offset:mmsize);
        eoinput = false;
    }
};

ISerialStream *createFileSerialStream(IMemoryMappedFile *mmfile, offset_t ofs, offset_t flen, IFileSerialStreamCallback *callback)
{
    return new CMemoryMappedSerialStream(mmfile,ofs,flen,callback);
}

ISerialStream *createMemorySerialStream(const void *buffer, memsize_t len, IFileSerialStreamCallback *callback)
{
    return new CMemoryMappedSerialStream(buffer,len,callback);
}

class CMemoryBufferSerialStream: public CInterface, implements ISerialStream
{
    MemoryBuffer & buffer;
    IFileSerialStreamCallback *tally;

public:
    IMPLEMENT_IINTERFACE;
    CMemoryBufferSerialStream(MemoryBuffer & _buffer, IFileSerialStreamCallback * _tally)
        : buffer(_buffer), tally(_tally)
    {
    }

    virtual const void *peek(size32_t sz,size32_t &got)
    {
        got = buffer.remaining();
        return buffer.readDirect(0);
    }

    virtual void get(size32_t len, void * ptr)
    {
        if (len>buffer.remaining()) {
            ERRLOG("CFileSerialStream::get read past end of stream.4(%u,%u)",(unsigned)len,(unsigned)buffer.remaining());
            throw MakeStringException(-1,"CMemoryBufferSerialStream::get read past end of stream (%u,%u)",(unsigned)len,(unsigned)buffer.remaining());
        }
        const void * data = buffer.readDirect(len);
        if (tally)
            tally->process(buffer.getPos()-len,len,data);
        memcpy(ptr,data,len);
    }

    virtual bool eos()
    {
        return buffer.remaining() == 0;
    }

    virtual void skip(size32_t len)
    {
        if (len>buffer.remaining())
            throw MakeStringException(-1,"CMemoryBufferSerialStream::skip read past end of stream (%u,%u)",(unsigned)len,(unsigned)buffer.remaining());

        const void * data = buffer.readDirect(len);
        if (tally)
            tally->process(buffer.getPos()-len,len,data);
    }

    virtual offset_t tell()
    {
        return buffer.getPos();
    }

    virtual void reset(offset_t _offset,offset_t _len)
    {
        size32_t ofs = (size32_t)_offset;
        assertex(ofs==_offset);
        assertex((_len==(offset_t)-1)||(_len>=buffer.length())); // don't support len on memory buffer
        buffer.reset(ofs);
    }
};

ISerialStream *createMemoryBufferSerialStream(MemoryBuffer & buffer, IFileSerialStreamCallback *callback)
{
    return new CMemoryBufferSerialStream(buffer,callback);
}



// Memory Mapped Files

#define MEMORYMAP_PAGESIZE  (0x1000) // could be different but won't ever be!

class CMemoryMappedFile: public CInterface, implements IMemoryMappedFile
{
    byte *ptr;            // base
    offset_t ofs;       
    offset_t realofs;    // rounded down to page size
    offset_t filesize;
    memsize_t size;
    bool writeaccess;          
    memsize_t windowsize;
    
    HANDLE hfile;
#ifdef _WIN32
    static size32_t pagesize;
    HANDLE hmap;
#endif  

    Linked<IFile> file;

    inline offset_t pageround(offset_t o)
    {
#ifdef _WIN32
        return o-(o%pagesize);
#else
        return o-(o%MEMORYMAP_PAGESIZE);
#endif
    }

    inline void * realptr()
    {
        return ptr?(ptr-(ofs-realofs)):NULL;
    }

    inline memsize_t realsize()
    {
        return (memsize_t)(size+(ofs-realofs));
    }

public:
    IMPLEMENT_IINTERFACE;

    CMemoryMappedFile(HANDLE _hfile, offset_t _filesize, offset_t _ofs, memsize_t _size, bool _writeaccess)
    {
        hfile = _hfile;
#ifdef _WIN32
        if (pagesize==0) {
            SYSTEM_INFO sysinfo;
            GetSystemInfo(&sysinfo);
            pagesize =  sysinfo.dwAllocationGranularity;
        }
        hmap = NULLFILE;
#endif
        ptr = NULL;
        filesize = _filesize;
        windowsize = _size;     // first open size assumed to be window size
        reinit(_ofs, _size, _writeaccess);
    }

    ~CMemoryMappedFile()
    {
#ifdef _WIN32
        if (hmap!=NULLFILE)
            CloseHandle(hmap);
        CloseHandle(hfile);
#else
        close(hfile);
#endif
    }

    byte *base()                        { return ptr; }
    offset_t offset()                   { return ofs; }
    virtual memsize_t length()          { return size; }
    virtual offset_t fileSize()         { return filesize; }
    virtual int compareWithin(const void *p)
    {
        if (p<ptr)
            return -1;
        if (p>=size+ptr)
            return 1;
        return 0;
    }
    bool writeAccess()                  { return writeaccess; }
    void flush()
    {
        if (ptr) {
#ifdef _WIN32
            FlushViewOfFile(realptr(),0);
#elif defined(__linux__)
            msync(realptr(),realsize(),MS_SYNC);
#else
            UNIMPLEMENTED;
#endif
        }
    }
    
    byte *nextPtr(const void *p,offset_t skip, memsize_t req, memsize_t &got)
    {
        // for scanning in sequence
        if (p==NULL) 
            p = ptr;
        else if ((p<ptr)||(p>ptr+size))
            throw MakeStringException(-1,"CMemoryMappedFile::nextPtr - outside map");           
        memsize_t d = (byte *)p-ptr;
        offset_t o = ofs+d+skip;
        if (o>=filesize) {
            got = 0;
            return NULL;
        }
        offset_t left = filesize-o;
        if (left<req)
            req = (memsize_t)left;
        if (o+req-ofs>size) {
            reinit(o,windowsize,writeaccess);
            assertex(o==ofs);
            got = windowsize;
            if (left<got)
                got = (memsize_t)left;
            return ptr;
        }
        got = (memsize_t)(size+o-ofs);
        if (left<got)
            got = (memsize_t)left;
        return (byte *)p+skip;
    }
        
    virtual void reinit(offset_t _ofs, memsize_t _size, bool _writeaccess)
    {
        writeaccess = _writeaccess;
        if (ptr) {
#ifdef _WIN32
            // no need to unmap view
            if (hmap != INVALID_HANDLE_VALUE) {
                CloseHandle(hmap);
                hmap = INVALID_HANDLE_VALUE;
            }
#elif defined(__linux__)
            munmap(realptr(),realsize());
            // error checking TBD
#else
            UNIMPLEMENTED;
#endif
            ptr = NULL;
        }
        if (_ofs>filesize)
            ofs = filesize;
        else
            ofs = _ofs;
        realofs = pageround(ofs);
        if (_size==(memsize_t)-1) {
            size = (memsize_t)(filesize-_ofs);
            if (size!=(filesize-_ofs)) 
                throw MakeStringException(-1,"CMemoryMappedFile::reinit file too big");         
        }
        else
            size = _size;
        memsize_t mapsz = realsize();
        if (filesize-realofs<mapsz)
            mapsz = (memsize_t)(filesize-realofs);
#ifdef _WIN32
        LARGE_INTEGER li;
        if (hmap == INVALID_HANDLE_VALUE) {
            hmap = CreateFileMapping(hfile,NULL,writeaccess?PAGE_READWRITE:PAGE_READONLY,0, 0, NULL);
            if (!hmap) {
                DWORD err = GetLastError();
                throw MakeOsException(err,"CMemoryMappedFile::reinit");
            }
        }
        li.QuadPart = realofs; 
        ptr = (byte *) MapViewOfFile(hmap, writeaccess?(FILE_MAP_READ|FILE_MAP_WRITE):FILE_MAP_READ, li.HighPart, li.LowPart, mapsz);
        if (!ptr) {
            DWORD err = GetLastError();
            throw MakeOsException(err,"CMemoryMappedFile::reinit");
        }
#elif defined (_linux__)
        ptr = (byte *) mmap(NULL, mapsz, writeaccess?(PROT_READ|PROT_WRITE):PROT_READ, MAP_SHARED|MAP_NORESERVE, hfile, realofs);
            // error checking TBD
#else
        UNIMPLEMENTED;
#endif
        if (ptr)
            ptr += (ofs-realofs);
    }


};

#ifdef _WIN32
size32_t CMemoryMappedFile::pagesize=0;
#endif

// TBD MADV_SEQUENTIAL & MADV_WILLNEED?



IMemoryMappedFile *CFile::openMemoryMapped(offset_t ofs, memsize_t len, bool write)
{
    HANDLE hfile = openHandle(write?IFOcreaterw:IFOread, IFSHread, false);
    if (hfile == NULLFILE) 
        return NULL;
    return new CMemoryMappedFile(hfile,size(),ofs,len,write);
}


bool isSpecialPath(const char *path)
{
    // used for remote queries
    if (!path)
        return false;
    if (isPathSepChar(path[0])&&(path[0]==path[1])) {
        path += 2;
        loop {
            if (*path=='/') 
                return (path[1]=='>');
            if (!*path||(*path=='\\'))
                return false;
            path++;
        }
    }
    return (path&&(*path=='/')&&(path[1]=='>'));
}


size32_t SendFile(ISocket *target, IFileIO *fileio,offset_t start,size32_t len)
{
    assertex(target);
    assertex(fileio);
    offset_t fsz = fileio->size();
    if (start>=fsz)
        return 0;
    if (start+len>fsz)
        len = (size32_t)(fsz-start);
    if (!len)
        return 0;
    CFileIO *cfile = QUERYINTERFACE(fileio,CFileIO);
    if (cfile) {
        HANDLE fh = cfile->queryHandle();
        if ((fh!=(HANDLE)0)&&(fh!=(HANDLE)-1)) {
            unsigned sh = target->OShandle();
            if ((sh!=(unsigned)0)&&(sh!=(unsigned)-1)) {
#ifdef _WIN32
                // MORE - should there be something here?
#elif defined(__linux__)
                // TransmitFile not in std DLLs so don't bother with
                off_t ofs = start;
                ssize_t sent = ::sendfile(sh,fh,&ofs,len);
                if (sent!=(ssize_t)-1) 
                    return (size32_t)sent;
                int err = errno;
                if ((err!=EINVAL)&&(err!=ENOSYS))
                    throw MakeOsException(err,"sendfile");
#else
                UNIMPLEMENTED;
#endif
            }
        }

    }

#ifdef _DEBUG
#ifndef _WIN32
    WARNLOG("SendFile falling back");
#endif
#endif

    // fallback
    MemoryAttr ma;
    void *buf = ma.allocate(len);
    size32_t rd = fileio->read(start,len,buf);
    target->write(buf,rd);
    return rd;
}


void asyncClose(IFileIO *io)
{
    if (!io)
        return;
    static CriticalSection ADsect;
    CriticalBlock block(ADsect);
    static Owned<IWorkQueueThread> adwp = createWorkQueueThread();
    class cWQI: public CInterface,implements IWorkQueueItem
    {
        Owned<IFileIO> io; 
    public:
        IMPLEMENT_IINTERFACE;
        cWQI(IFileIO *_io)
            : io(_io)
        {
        }

        void execute()
        {
            io.clear();
        }
    };
    adwp->post(new cWQI(io));
};

int stdIoHandle(const char *path)
{
    if (strcmp(path,"stdin:")==0)
        return 0;
    if (strcmp(path,"stdout:")==0)
        return 1;
    if (strcmp(path,"stderr:")==0)
        return 2;
    return -1;
}

extern jlib_decl bool containsFileWildcard(const char * path)
{
    if (!path)
        return false;
    return strchr(path, '*') || strchr(path, '?');
}

extern jlib_decl bool isDirectory(const char * path)
{
    Owned<IFile> file = createIFile(path);
    return file->isDirectory() == foundYes;
}

// IFileIOCache

class CLazyFileIOCache;

class CCachedFileIO: public CInterface, implements IFileIO
{
    CLazyFileIOCache &owner;
    RemoteFilename filename;
    CriticalSection &sect;
    IFOmode mode;

    void writeNotSupported(const char *s)
    {
        StringBuffer tmp;
        filename.getRemotePath(tmp);
        throw MakeStringException(-1, "CCachedFileIO(%s) %s not supported", tmp.str(), s);
    }
public:
    unsigned accesst;
    Owned<IFileIO> cachedio;


    CCachedFileIO(CLazyFileIOCache &_owner, CriticalSection &_sect, RemoteFilename &_filename, IFOmode _mode)
        : owner(_owner), sect(_sect)
    {
        filename.set(_filename);
        mode = _mode;
    }

    virtual void Link(void) const       { CInterface::Link(); }                     \

    virtual bool Release(void) const;
    

    IFileIO *open();

    size32_t read(offset_t pos, size32_t len, void * data)
    {
        CriticalBlock block(sect);
        Owned<IFileIO> io = open();
        return io->read(pos,len,data);
    }
    offset_t size() 
    {
        CriticalBlock block(sect);
        Owned<IFileIO> io = open();
        return io->size();
    }
    size32_t write(offset_t pos, size32_t len, const void * data) 
    {
        CriticalBlock block(sect);
        Owned<IFileIO> io = open();
        return io->write(pos,len,data);
    }
    offset_t appendFile(IFile *file,offset_t pos,offset_t len)
    {
        CriticalBlock block(sect);
        Owned<IFileIO> io = open();
        return io->appendFile(file,pos,len);
    }
    void setSize(offset_t size) 
    {
        CriticalBlock block(sect);
        Owned<IFileIO> io = open();
        io->setSize(size);
    }

};

class CLazyFileIOCache: public CInterface, implements IFileIOCache
{
    CriticalSection sect;
    unsigned max;
    PointerIArrayOf<CCachedFileIO> cache;
public:
    IMPLEMENT_IINTERFACE;

    CLazyFileIOCache(unsigned _max)
    {
        max = _max;
    }
    CCachedFileIO *addFile( RemoteFilename  &filename, IFOmode mode )
    {
        // check exists
        unsigned i = cache.ordinality();
        ForEachItemIn(i2,cache) {
            if (!cache.item(i2)) {
                i = i2;
                break;
            }
        }
        Linked<CCachedFileIO> ret = new CCachedFileIO(*this,sect,filename,mode);
        if (i<cache.ordinality())
            cache.replace(ret,i);
        else
            cache.append(ret);
        return ret.getClear();
    }

    void checkCache(unsigned wanted=1)
    {
        // called in sect
        loop {
            CCachedFileIO *oldest = NULL;
            unsigned oldestt = 0;
            unsigned t = msTick();
            unsigned n = wanted;
            ForEachItemIn(i1,cache) {
                CCachedFileIO *cio = cache.item(i1);
                if (cio&&cio->cachedio.get()) {
                    if (t-cio->accesst>=oldestt) {
                        oldest = cio;
                        oldestt = t-cio->accesst;
                    }
                    n++;
                }
            }
            if (n<max)
                break;
            if (!oldest)
                break;
            oldest->cachedio.clear();
        }
    }

    const CCachedFileIO *removeFile(const CCachedFileIO *io) 
    {
        CriticalBlock block(sect);
        ForEachItemIn(oi,cache) {
            if (io = cache.item(oi)) {
                cache.replace(NULL,oi,true);    
                break;
            }
        }
        return io;
    }

};


bool CCachedFileIO::Release(void) const 
{ 
    if (CInterface::Release())
        return true;
    if (!CInterface::IsShared()) 
        return owner.removeFile(this)->Release();
    return false;
}

IFileIO *CCachedFileIO::open()
{
    // called in sect
    if (!cachedio) {
        owner.checkCache();
        Owned<IFile> inFile = createIFile(filename);
        cachedio.setown(inFile->open(mode));
        if (!cachedio.get()) {
            StringBuffer tmp;
            filename.getRemotePath(tmp);
            throw MakeStringException(-1, "CCachedFileIO::open(%d) '%s' failed", (int)mode, tmp.str());
        }
    }
    accesst = msTick();
    return cachedio.getLink();
}


IFileIOCache* createFileIOCache(unsigned max)
{
    return new CLazyFileIOCache(max);
}


extern jlib_decl IFile * createSentinelTarget()
{
    const char * sentinelFilename = getenv("SENTINEL");
    if (sentinelFilename)
        return createIFile(sentinelFilename);
    else
        return NULL;
}

extern jlib_decl void removeSentinelFile(IFile * sentinelFile)
{
    if (sentinelFile)
    {
        if(sentinelFile->exists() && !sentinelFile->isDirectory())
        {
            DBGLOG("Removing sentinel file %s", sentinelFile->queryFilename());
            try
            {
                sentinelFile->remove();
            }
            catch(IException *E)
            {
                StringBuffer s;
                EXCLOG(E, s.appendf("Failed to remove sentinel file %s", sentinelFile->queryFilename()).str());
                E->Release();
                throw MakeOsException(errno, "removeSentinelFile - file cannot be removed.");
            }
        }
    }
}

extern jlib_decl void writeSentinelFile(IFile * sentinelFile)
{
    if ( sentinelFile )
    {
        DBGLOG("Creating sentinel file %s for rerun from script", sentinelFile->queryFilename());
        try
        {
            Owned<IFileIO> sentinel = sentinelFile->open(IFOcreate);
            sentinel->write(0, 5, "rerun");
        }
        catch(IException *E)
        {
            StringBuffer s;
            EXCLOG(E, s.appendf("Failed to create sentinel file %s for rerun from script", sentinelFile->queryFilename()).str());
            E->Release();
            throw MakeOsException(errno, "writeSentinelFile - file not created.");
        }
    }
}

jlib_decl StringBuffer & appendCurrentDirectory(StringBuffer & target, bool blankIfFails)
{
    char temp[_MAX_PATH+1];
    if (!getcwd(temp,sizeof(temp)))
    {
        if (blankIfFails)
            return target;
        throw MakeStringException(JLIBERR_InternalError, "getcwd failed (%d)", errno);
    }
    return target.append(temp);
}