projects / OpenSPARC-T2-DV / blame
| Commit | Line | Data |
|---|---|---|
| 86530b38 AT |
1 | """Maintain a cache of stat() information on files. |
| 2 | ||
| 3 | There are functions to reset the cache or to selectively remove items. | |
| 4 | """ | |
| 5 | ||
| 6 | import warnings | |
| 7 | warnings.warn("The statcache module is obsolete. Use os.stat() instead.", | |
| 8 | DeprecationWarning) | |
| 9 | del warnings | |
| 10 | ||
| 11 | import os as _os | |
| 12 | from stat import * | |
| 13 | ||
| 14 | __all__ = ["stat","reset","forget","forget_prefix","forget_dir", | |
| 15 | "forget_except_prefix","isdir"] | |
| 16 | ||
| 17 | # The cache. Keys are pathnames, values are os.stat outcomes. | |
| 18 | # Remember that multiple threads may be calling this! So, e.g., that | |
| 19 | # path in cache returns 1 doesn't mean the cache will still contain | |
| 20 | # path on the next line. Code defensively. | |
| 21 | ||
| 22 | cache = {} | |
| 23 | ||
| 24 | def stat(path): | |
| 25 | """Stat a file, possibly out of the cache.""" | |
| 26 | ret = cache.get(path, None) | |
| 27 | if ret is None: | |
| 28 | cache[path] = ret = _os.stat(path) | |
| 29 | return ret | |
| 30 | ||
| 31 | def reset(): | |
| 32 | """Clear the cache.""" | |
| 33 | cache.clear() | |
| 34 | ||
| 35 | # For thread saftey, always use forget() internally too. | |
| 36 | def forget(path): | |
| 37 | """Remove a given item from the cache, if it exists.""" | |
| 38 | try: | |
| 39 | del cache[path] | |
| 40 | except KeyError: | |
| 41 | pass | |
| 42 | ||
| 43 | def forget_prefix(prefix): | |
| 44 | """Remove all pathnames with a given prefix.""" | |
| 45 | for path in cache.keys(): | |
| 46 | if path.startswith(prefix): | |
| 47 | forget(path) | |
| 48 | ||
| 49 | def forget_dir(prefix): | |
| 50 | """Forget a directory and all entries except for entries in subdirs.""" | |
| 51 | ||
| 52 | # Remove trailing separator, if any. This is tricky to do in a | |
| 53 | # x-platform way. For example, Windows accepts both / and \ as | |
| 54 | # separators, and if there's nothing *but* a separator we want to | |
| 55 | # preserve that this is the root. Only os.path has the platform | |
| 56 | # knowledge we need. | |
| 57 | from os.path import split, join | |
| 58 | prefix = split(join(prefix, "xxx"))[0] | |
| 59 | forget(prefix) | |
| 60 | for path in cache.keys(): | |
| 61 | # First check that the path at least starts with the prefix, so | |
| 62 | # that when it doesn't we can avoid paying for split(). | |
| 63 | if path.startswith(prefix) and split(path)[0] == prefix: | |
| 64 | forget(path) | |
| 65 | ||
| 66 | def forget_except_prefix(prefix): | |
| 67 | """Remove all pathnames except with a given prefix. | |
| 68 | ||
| 69 | Normally used with prefix = '/' after a chdir(). | |
| 70 | """ | |
| 71 | ||
| 72 | for path in cache.keys(): | |
| 73 | if not path.startswith(prefix): | |
| 74 | forget(path) | |
| 75 | ||
| 76 | def isdir(path): | |
| 77 | """Return True if directory, else False.""" | |
| 78 | try: | |
| 79 | st = stat(path) | |
| 80 | except _os.error: | |
| 81 | return False | |
| 82 | return S_ISDIR(st.st_mode) |