HPCC-8957 - Compressed files being published with incorrect crc

When block compression files are created, implicitly a crc of
0 is always the result. The published crc should be ~<crc-val>
but in case of compressed files it was publishing 0.

This was noticed only by VerifyFile

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>

dali/base/dadfs.cpp

@@ -1820,7 +1820,6 @@ public:
     void set(IPropertyTree *pt,FileClusterInfoArray &clusters,unsigned maxcluster);
     RemoteFilename &getFilename(RemoteFilename &ret,unsigned copy);
     void renameFile(IFile *file);
-    unsigned getCRC();
     IPropertyTree &queryAttributes();
     bool lockProperties(unsigned timems);
     void unlockProperties(DFTransactionState state);

thorlcr/activities/thdiskbaseslave.cpp

@@ -329,6 +329,7 @@ void CDiskWriteSlaveActivityBase::open()
     if (compress)
     {
         ActPrintLog("Performing row compression on output file: %s", fName.get());
+        // NB: block compressed output has implicit crc of 0, no need to calculate in row  writer.
         calcFileCrc = false;
     }
     Owned<IFileIOStream> stream;
@@ -557,8 +558,9 @@ void CDiskWriteSlaveActivityBase::processDone(MemoryBuffer &mb)
     if (-1 != sz)
         container.queryJob().queryIDiskUsage().increase(sz);
     mb.append(_processed).append(compress?uncompressedBytesWritten:sz).append(sz);
+    // NB: block compressed output has implicit crc of 0.
     unsigned crc = compress?~0:fileCRC.get();
-    mb.append(calcFileCrc?crc:0);
+    mb.append(crc);
 
     CDateTime createTime, modifiedTime, accessedTime;
     ifile->getTime(&createTime, &modifiedTime, &accessedTime);