76 lines
1.5 KiB
Python
Executable File
76 lines
1.5 KiB
Python
Executable File
"""Maintain a cache of stat() information on files.
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There are functions to reset the cache or to selectively remove items.
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"""
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import os
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from stat import *
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# The cache.
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# Keys are pathnames, values are `os.stat' outcomes.
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#
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cache = {}
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def stat(path):
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"""Stat a file, possibly out of the cache."""
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if cache.has_key(path):
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return cache[path]
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cache[path] = ret = os.stat(path)
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return ret
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def reset():
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"""Reset the cache completely."""
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global cache
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cache = {}
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def forget(path):
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"""Remove a given item from the cache, if it exists."""
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if cache.has_key(path):
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del cache[path]
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def forget_prefix(prefix):
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"""Remove all pathnames with a given prefix."""
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n = len(prefix)
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for path in cache.keys():
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if path[:n] == prefix:
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del cache[path]
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def forget_dir(prefix):
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"""Forget about a directory and all entries in it, but not about
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entries in subdirectories."""
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if prefix[-1:] == '/' and prefix <> '/':
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prefix = prefix[:-1]
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forget(prefix)
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if prefix[-1:] <> '/':
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prefix = prefix + '/'
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n = len(prefix)
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for path in cache.keys():
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if path[:n] == prefix:
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rest = path[n:]
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if rest[-1:] == '/': rest = rest[:-1]
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if '/' not in rest:
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del cache[path]
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def forget_except_prefix(prefix):
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"""Remove all pathnames except with a given prefix.
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Normally used with prefix = '/' after a chdir()."""
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n = len(prefix)
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for path in cache.keys():
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if path[:n] <> prefix:
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del cache[path]
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def isdir(path):
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"""Check for directory."""
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try:
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st = stat(path)
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except os.error:
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return 0
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return S_ISDIR(st[ST_MODE])
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