1 files changed, 70 insertions, 0 deletions
diff --git a/webapp/django/core/files/locks.py b/webapp/django/core/files/locks.py
new file mode 100644
index 0000000000..98a11551a7
--- /dev/null
+++ b/webapp/django/core/files/locks.py
@@ -0,0 +1,70 @@
+"""
+Portable file locking utilities.
+
+Based partially on example by Jonathan Feignberg <jdf@pobox.com> in the Python
+Cookbook, licensed under the Python Software License.
+
+    http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/65203
+
+Example Usage::
+
+    >>> from django.core.files import locks
+    >>> f = open('./file', 'wb')
+    >>> locks.lock(f, locks.LOCK_EX)
+    >>> f.write('Django')
+    >>> f.close()
+"""
+
+__all__ = ('LOCK_EX','LOCK_SH','LOCK_NB','lock','unlock')
+
+system_type = None
+
+try:
+    import win32con
+    import win32file
+    import pywintypes
+    LOCK_EX = win32con.LOCKFILE_EXCLUSIVE_LOCK
+    LOCK_SH = 0
+    LOCK_NB = win32con.LOCKFILE_FAIL_IMMEDIATELY
+    __overlapped = pywintypes.OVERLAPPED()
+    system_type = 'nt'
+except (ImportError, AttributeError):
+    pass
+
+try:
+    import fcntl
+    LOCK_EX = fcntl.LOCK_EX
+    LOCK_SH = fcntl.LOCK_SH
+    LOCK_NB = fcntl.LOCK_NB
+    system_type = 'posix'
+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(fd(file))
+        win32file.LockFileEx(hfile, flags, 0, -0x10000, __overlapped)
+
+    def unlock(file):
+        hfile = win32file._get_osfhandle(fd(file))
+        win32file.UnlockFileEx(hfile, 0, -0x10000, __overlapped)
+elif system_type == 'posix':
+    def lock(file, flags):
+        fcntl.flock(fd(file), flags)
+
+    def unlock(file):
+        fcntl.flock(fd(file), fcntl.LOCK_UN)
+else:
+    # File locking is not supported.
+    LOCK_EX = LOCK_SH = LOCK_NB = None
+
+    # Dummy functions that don't do anything.
+    def lock(file, flags):
+        pass
+
+    def unlock(file):
+        pass