Mercurial > cpython-lru_cache-weakref

annotate Lib/statcache.py @ 15946:4f621708514b legacy-trunk

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Rich comparisons fall-out: - Get rid of long_cmp(). - Renamed Py_TPFLAGS_NEWSTYLENUMBER to Py_TPFLAGS_CHECKTYPES.
author Guido van Rossum <guido@python.org>
date Wed, 17 Jan 2001 15:33:18 +0000
parents 3685ef2a55a4
children 861bf8dcfb58
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 """Maintain a cache of stat() information on files.
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3 There are functions to reset the cache or to selectively remove items.
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4 """
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6 import os
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961696ef3ab7 Use 'stat' module instead of hardcoding information from <sys/stat.h>.
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7 from stat import *
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8
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9 # The cache.
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10 # Keys are pathnames, values are `os.stat' outcomes.
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11 #
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12 cache = {}
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15 def stat(path):
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16 """Stat a file, possibly out of the cache."""
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17 if cache.has_key(path):
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18 return cache[path]
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19 cache[path] = ret = os.stat(path)
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20 return ret
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23 def reset():
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24 """Reset the cache completely."""
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25 global cache
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26 cache = {}
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29 def forget(path):
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30 """Remove a given item from the cache, if it exists."""
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31 if cache.has_key(path):
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32 del cache[path]
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35 def forget_prefix(prefix):
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36 """Remove all pathnames with a given prefix."""
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37 n = len(prefix)
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38 for path in cache.keys():
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39 if path[:n] == prefix:
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40 del cache[path]
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43 def forget_dir(prefix):
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44 """Forget about a directory and all entries in it, but not about
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45 entries in subdirectories."""
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46 if prefix[-1:] == '/' and prefix != '/':
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47 prefix = prefix[:-1]
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48 forget(prefix)
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49 if prefix[-1:] != '/':
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50 prefix = prefix + '/'
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51 n = len(prefix)
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52 for path in cache.keys():
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53 if path[:n] == prefix:
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54 rest = path[n:]
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55 if rest[-1:] == '/': rest = rest[:-1]
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56 if '/' not in rest:
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57 del cache[path]
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60 def forget_except_prefix(prefix):
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61 """Remove all pathnames except with a given prefix.
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62 Normally used with prefix = '/' after a chdir()."""
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63 n = len(prefix)
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64 for path in cache.keys():
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65 if path[:n] != prefix:
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66 del cache[path]
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69 def isdir(path):
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70 """Check for directory."""
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71 try:
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72 st = stat(path)
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73 except os.error:
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74 return 0
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75 return S_ISDIR(st[ST_MODE])