[utils] Improve file locking
* Implement non-blocking locks for windows * Don't raise error when closing a closed file
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1 changed files with 12 additions and 8 deletions
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@ -2122,22 +2122,22 @@ if sys.platform == 'win32':
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whole_low = 0xffffffff
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whole_high = 0x7fffffff
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def _lock_file(f, exclusive, block): # todo: block unused on win32
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def _lock_file(f, exclusive, block):
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overlapped = OVERLAPPED()
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overlapped.Offset = 0
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overlapped.OffsetHigh = 0
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overlapped.hEvent = 0
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f._lock_file_overlapped_p = ctypes.pointer(overlapped)
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handle = msvcrt.get_osfhandle(f.fileno())
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if not LockFileEx(handle, 0x2 if exclusive else 0x0, 0,
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whole_low, whole_high, f._lock_file_overlapped_p):
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raise OSError('Locking file failed: %r' % ctypes.FormatError())
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if not LockFileEx(msvcrt.get_osfhandle(f.fileno()),
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(0x2 if exclusive else 0x0) | (0x0 if block else 0x1),
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0, whole_low, whole_high, f._lock_file_overlapped_p):
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raise BlockingIOError('Locking file failed: %r' % ctypes.FormatError())
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def _unlock_file(f):
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assert f._lock_file_overlapped_p
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handle = msvcrt.get_osfhandle(f.fileno())
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if not UnlockFileEx(handle, 0,
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whole_low, whole_high, f._lock_file_overlapped_p):
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if not UnlockFileEx(handle, 0, whole_low, whole_high, f._lock_file_overlapped_p):
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raise OSError('Unlocking file failed: %r' % ctypes.FormatError())
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else:
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@ -2175,6 +2175,8 @@ else:
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class locked_file(object):
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_closed = False
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def __init__(self, filename, mode, block=True, encoding=None):
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assert mode in ['r', 'rb', 'a', 'ab', 'w', 'wb']
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self.f = io.open(filename, mode, encoding=encoding)
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@ -2192,9 +2194,11 @@ class locked_file(object):
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def __exit__(self, etype, value, traceback):
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try:
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_unlock_file(self.f)
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if not self._closed:
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_unlock_file(self.f)
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finally:
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self.f.close()
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self._closed = True
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def __iter__(self):
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return iter(self.f)
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