1 files changed, 88 insertions, 0 deletions
diff --git a/webapp/django/core/files/move.py b/webapp/django/core/files/move.py
new file mode 100644
index 0000000000..58a0ab125d
--- /dev/null
+++ b/webapp/django/core/files/move.py
@@ -0,0 +1,88 @@
+"""
+Move a file in the safest way possible::
+
+    >>> from django.core.files.move import file_move_save
+    >>> file_move_save("/tmp/old_file", "/tmp/new_file")
+"""
+
+import os
+from django.core.files import locks
+
+try:
+    from shutil import copystat
+except ImportError:
+    def copystat(src, dst):
+        """Copy all stat info (mode bits, atime and mtime) from src to dst"""
+        st = os.stat(src)
+        mode = stat.S_IMODE(st.st_mode)
+        if hasattr(os, 'utime'):
+            os.utime(dst, (st.st_atime, st.st_mtime))
+        if hasattr(os, 'chmod'):
+            os.chmod(dst, mode)
+
+__all__ = ['file_move_safe']
+
+def _samefile(src, dst):
+    # Macintosh, Unix.
+    if hasattr(os.path,'samefile'):
+        try:
+            return os.path.samefile(src, dst)
+        except OSError:
+            return False
+
+    # All other platforms: check for same pathname.
+    return (os.path.normcase(os.path.abspath(src)) ==
+            os.path.normcase(os.path.abspath(dst)))
+
+def file_move_safe(old_file_name, new_file_name, chunk_size = 1024*64, allow_overwrite=False):
+    """
+    Moves a file from one location to another in the safest way possible.
+
+    First, try using ``shutils.move``, which is OS-dependent but doesn't break
+    if moving across filesystems. Then, try ``os.rename``, which will break
+    across filesystems. Finally, streams manually from one file to another in
+    pure Python.
+
+    If the destination file exists and ``allow_overwrite`` is ``False``, this
+    function will throw an ``IOError``.
+    """
+
+    # There's no reason to move if we don't have to.
+    if _samefile(old_file_name, new_file_name):
+        return
+
+    try:
+        os.rename(old_file_name, new_file_name)
+        return
+    except OSError:
+        # This will happen with os.rename if moving to another filesystem
+        # or when moving opened files on certain operating systems
+        pass
+
+    # first open the old file, so that it won't go away
+    old_file = open(old_file_name, 'rb')
+    try:
+        # now open the new file, not forgetting allow_overwrite
+        fd = os.open(new_file_name, os.O_WRONLY | os.O_CREAT | getattr(os, 'O_BINARY', 0) |
+                                    (not allow_overwrite and os.O_EXCL or 0))
+        try:
+            locks.lock(fd, locks.LOCK_EX)
+            current_chunk = None
+            while current_chunk != '':
+                current_chunk = old_file.read(chunk_size)
+                os.write(fd, current_chunk)
+        finally:
+            locks.unlock(fd)
+            os.close(fd)
+    finally:
+        old_file.close()
+    copystat(old_file_name, new_file_name)
+
+    try:
+        os.remove(old_file_name)
+    except OSError, e:
+        # Certain operating systems (Cygwin and Windows)
+        # fail when deleting opened files, ignore it
+        if getattr(e, 'winerror', 0) != 32:
+            # FIXME: should we also ignore errno 13?
+            raise