Fixed #4948, a race condition in file saving. Thanks to Martin von Löwis, who diagnosed the problem and pointed the way to a fix.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8306 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 8 insertions, 4 deletions

diff --git a/django/core/files/locks.py b/django/core/files/locks.py
index 212b51a73d..98a11551a7 100644
--- a/django/core/files/locks.py
+++ b/django/core/files/locks.py
@@ -40,20 +40,24 @@ try:
 except (ImportError, AttributeError):
     pass
 
+def fd(f):
+    """Get a filedescriptor from something which could be a file or an fd."""
+    return hasattr(f, 'fileno') and f.fileno() or f
+
 if system_type == 'nt':
     def lock(file, flags):
-        hfile = win32file._get_osfhandle(file.fileno())
+        hfile = win32file._get_osfhandle(fd(file))
         win32file.LockFileEx(hfile, flags, 0, -0x10000, __overlapped)
 
     def unlock(file):
-        hfile = win32file._get_osfhandle(file.fileno())
+        hfile = win32file._get_osfhandle(fd(file))
         win32file.UnlockFileEx(hfile, 0, -0x10000, __overlapped)
 elif system_type == 'posix':
     def lock(file, flags):
-        fcntl.flock(file.fileno(), flags)
+        fcntl.flock(fd(file), flags)
 
     def unlock(file):
-        fcntl.flock(file.fileno(), fcntl.LOCK_UN)
+        fcntl.flock(fd(file), fcntl.LOCK_UN)
 else:
     # File locking is not supported.
     LOCK_EX = LOCK_SH = LOCK_NB = None