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-rw-r--r--youtube_dl/utils.py96
1 files changed, 96 insertions, 0 deletions
diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index e3feb12bf..de2654762 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -830,3 +830,99 @@ def get_cachedir(params={}):
cache_root = os.environ.get('XDG_CACHE_HOME',
os.path.expanduser('~/.cache'))
return params.get('cachedir', os.path.join(cache_root, 'youtube-dl'))
+
+
+# Cross-platform file locking
+if sys.platform == 'win32':
+ import ctypes.wintypes
+ import msvcrt
+
+ class OVERLAPPED(ctypes.Structure):
+ _fields_ = [
+ ('Internal', ctypes.wintypes.LPVOID),
+ ('InternalHigh', ctypes.wintypes.LPVOID),
+ ('Offset', ctypes.wintypes.DWORD),
+ ('OffsetHigh', ctypes.wintypes.DWORD),
+ ('hEvent', ctypes.wintypes.HANDLE),
+ ]
+
+ kernel32 = ctypes.windll.kernel32
+ LockFileEx = kernel32.LockFileEx
+ LockFileEx.argtypes = [
+ ctypes.wintypes.HANDLE, # hFile
+ ctypes.wintypes.DWORD, # dwFlags
+ ctypes.wintypes.DWORD, # dwReserved
+ ctypes.wintypes.DWORD, # nNumberOfBytesToLockLow
+ ctypes.wintypes.DWORD, # nNumberOfBytesToLockHigh
+ ctypes.POINTER(OVERLAPPED) # Overlapped
+ ]
+ LockFileEx.restype = ctypes.wintypes.BOOL
+ UnlockFileEx = kernel32.UnlockFileEx
+ UnlockFileEx.argtypes = [
+ ctypes.wintypes.HANDLE, # hFile
+ ctypes.wintypes.DWORD, # dwReserved
+ ctypes.wintypes.DWORD, # nNumberOfBytesToLockLow
+ ctypes.wintypes.DWORD, # nNumberOfBytesToLockHigh
+ ctypes.POINTER(OVERLAPPED) # Overlapped
+ ]
+ UnlockFileEx.restype = ctypes.wintypes.BOOL
+ whole_low = 0xffffffff
+ whole_high = 0x7fffffff
+
+ def _lock_file(f, exclusive):
+ overlapped = OVERLAPPED()
+ overlapped.Offset = 0
+ overlapped.OffsetHigh = 0
+ overlapped.hEvent = 0
+ f._lock_file_overlapped_p = ctypes.pointer(overlapped)
+ handle = msvcrt.get_osfhandle(f.fileno())
+ if not LockFileEx(handle, 0x2 if exclusive else 0x0, 0,
+ whole_low, whole_high, f._lock_file_overlapped_p):
+ raise OSError('Locking file failed: %r' % ctypes.FormatError())
+
+ def _unlock_file(f):
+ assert f._lock_file_overlapped_p
+ handle = msvcrt.get_osfhandle(f.fileno())
+ if not UnlockFileEx(handle, 0,
+ whole_low, whole_high, f._lock_file_overlapped_p):
+ raise OSError('Unlocking file failed: %r' % ctypes.FormatError())
+
+else:
+ import fcntl
+
+ def _lock_file(f, exclusive):
+ fcntl.lockf(f, fcntl.LOCK_EX if exclusive else fcntl.LOCK_SH)
+
+ def _unlock_file(f):
+ fcntl.lockf(f, fcntl.LOCK_UN)
+
+
+class locked_file(object):
+ def __init__(self, filename, mode, encoding=None):
+ assert mode in ['r', 'a', 'w']
+ self.f = io.open(filename, mode, encoding=encoding)
+ self.mode = mode
+
+ def __enter__(self):
+ exclusive = self.mode != 'r'
+ try:
+ _lock_file(self.f, exclusive)
+ except IOError:
+ self.f.close()
+ raise
+ return self
+
+ def __exit__(self, etype, value, traceback):
+ try:
+ _unlock_file(self.f)
+ finally:
+ self.f.close()
+
+ def __iter__(self):
+ return iter(self.f)
+
+ def write(self, *args):
+ return self.f.write(*args)
+
+ def read(self, *args):
+ return self.f.read(*args)