[Python-checkins] r84043 - python/branches/py3k/Lib/re.py
raymond.hettinger
python-checkins at python.org
Sat Aug 14 23:17:49 CEST 2010
Author: raymond.hettinger
Date: Sat Aug 14 23:17:48 2010
New Revision: 84043
Log:
Clean-up the cache patch for the re module.
Modified:
python/branches/py3k/Lib/re.py
Modified: python/branches/py3k/Lib/re.py
==============================================================================
--- python/branches/py3k/Lib/re.py (original)
+++ python/branches/py3k/Lib/re.py Sat Aug 14 23:17:48 2010
@@ -250,53 +250,14 @@
# --------------------------------------------------------------------
# internals
-_cache = {}
-_cache_repl = {}
-
_pattern_type = type(sre_compile.compile("", 0))
-_MAXCACHE = 500
-
-def _shrink_cache(cache_dict, max_length, divisor=5):
- """Make room in the given cache.
-
- Args:
- cache_dict: The cache dictionary to modify.
- max_length: Maximum # of entries in cache_dict before it is shrunk.
- divisor: Cache will shrink to max_length - 1/divisor*max_length items.
- """
- # Toss out a fraction of the entries at random to make room for new ones.
- # A random algorithm was chosen as opposed to simply cache_dict.popitem()
- # as popitem could penalize the same regular expression repeatedly based
- # on its internal hash value. Being random should spread the cache miss
- # love around.
- cache_keys = tuple(cache_dict.keys())
- overage = len(cache_keys) - max_length
- if overage < 0:
- # Cache is already within limits. Normally this should not happen
- # but it could due to multithreading.
- return
- number_to_toss = max_length // divisor + overage
- # The import is done here to avoid a circular depencency.
- import random
- if not hasattr(random, 'sample'):
- # Do nothing while resolving the circular dependency:
- # re->random->warnings->tokenize->string->re
- return
- for doomed_key in random.sample(cache_keys, number_to_toss):
- try:
- del cache_dict[doomed_key]
- except KeyError:
- # Ignore problems if the cache changed from another thread.
- pass
-
-def _compile(*args):
- return _compile_typed(type(args[0]), *args)
+def _compile(pattern, flags):
+ return _compile_typed(type(pattern), pattern, flags)
- at functools.lru_cache(maxsize=_MAXCACHE)
-def _compile_typed(type, *key):
+ at functools.lru_cache(maxsize=500)
+def _compile_typed(text_bytes_type, pattern, flags):
# internal: compile pattern
- pattern, flags = key
if isinstance(pattern, _pattern_type):
if flags:
raise ValueError(
@@ -305,12 +266,10 @@
if not sre_compile.isstring(pattern):
raise TypeError("first argument must be string or compiled pattern")
return sre_compile.compile(pattern, flags)
- return p
- at functools.lru_cache(maxsize=_MAXCACHE)
-def _compile_repl(*key):
+ at functools.lru_cache(maxsize=500)
+def _compile_repl(repl, pattern):
# internal: compile replacement pattern
- repl, pattern = key
return sre_parse.parse_template(repl, pattern)
def _expand(pattern, match, template):
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