Geografic-Information-System/gui/wxpython/startup/utils.py

"""
@package startup.utils

@brief General utilities for GUI startup of GRASS GIS

(C) 2017-2018 by Vaclav Petras the GRASS Development Team

This program is free software under the GNU General Public License
(>=v2). Read the file COPYING that comes with GRASS for details.

@author Vaclav Petras <wenzeslaus gmail com>
"""


import os


def get_possible_database_path():
    """Finds a path to what is possibly a GRASS Database. 

    Looks for directory named grassdata in the usual locations.

    Returns the path as a string or None if nothing was found, so the
    return value can be used to test if the directory was found.
    """
    home = os.path.expanduser('~')
    # try some common directories for grassdata
    # grassdata (lowercase) in home for Linux (first choice)
    # Documents and My Documents for Windows
    # potential translations (old Windows and some Linux)
    # but ~ and ~/Documents should cover most of the cases
    # ordered by preference and then likelihood
    candidates = [
        os.path.join(home, "grassdata"),
        os.path.join(home, "Documents", "grassdata"),
        os.path.join(home, "My Documents", "grassdata"),
    ]
    try:
        # here goes everything which has potential unicode issues
        candidates.append(os.path.join(home, _("Documents"), "grassdata"))
        candidates.append(os.path.join(home, _("My Documents"), "grassdata"))
    except UnicodeDecodeError:
        # just ignore the errors if it doesn't work
        pass
    path = None
    for candidate in candidates:
        if os.path.exists(candidate):
            path = candidate
            break  # get the first match
    return path


def get_lockfile_if_present(database, location, mapset):
    """Return path to lock if present, None otherwise

    Returns the path as a string or None if nothing was found, so the
    return value can be used to test if the lock is present.
    """
    lock_name = '.gislock'
    lockfile = os.path.join(database, location, mapset, lock_name)
    if os.path.isfile(lockfile):
        return lockfile
    else:
        return None