cache.py 文件源码

def __init__(self, folder, file_lock_time_wait=0.1):
            self.folder = folder
            self.key_filter_in = lambda key: key
            self.key_filter_out = lambda key: key
            self.file_lock_time_wait = file_lock_time_wait
            # How long we should wait before retrying to lock a file held by another process
            # We still need a mutex for each file as portalocker only blocks other processes
            self.file_locks = defaultdict(thread.allocate_lock)

            # Make sure we use valid filenames.
            if sys.platform == "win32":
                import base64

                def key_filter_in_windows(key):
                    """
                    Windows doesn't allow \ / : * ? "< > | in filenames.
                    To go around this encode the keys with base32.
                    """
                    return to_native(base64.b32encode(to_bytes(key)))

                def key_filter_out_windows(key):
                    """
                    We need to decode the keys so regex based removal works.
                    """
                    return to_native(base64.b32decode(to_bytes(key)))

                self.key_filter_in = key_filter_in_windows
                self.key_filter_out = key_filter_out_windows