1 files changed, 31 insertions, 13 deletions
diff --git a/Lib/fnmatch.py b/Lib/fnmatch.py
index 726fbe5..7c20e74 100644
--- a/Lib/fnmatch.py
+++ b/Lib/fnmatch.py
@@ -12,9 +12,19 @@ corresponding to PATTERN.  (It does not compile it.)
 import os
 import posixpath
 import re
-import functools
 
-__all__ = ["filter", "fnmatch", "fnmatchcase", "translate"]
+__all__ = ["filter", "fnmatch", "fnmatchcase", "purge", "translate"]
+
+_cache = {}  # Maps text patterns to compiled regexen.
+_cacheb = {}  # Ditto for bytes patterns.
+_MAXCACHE = 100  # Maximum size of caches.
+
+
+def purge():
+    """Clear the pattern cache."""
+    _cache.clear()
+    _cacheb.clear()
+
 
 def fnmatch(name, pat):
     """Test whether FILENAME matches PATTERN.
@@ -35,21 +45,28 @@ def fnmatch(name, pat):
     pat = os.path.normcase(pat)
     return fnmatchcase(name, pat)
 
-@functools.lru_cache(maxsize=250)
-def _compile_pattern(pat, is_bytes=False):
-    if is_bytes:
-        pat_str = str(pat, 'ISO-8859-1')
-        res_str = translate(pat_str)
-        res = bytes(res_str, 'ISO-8859-1')
-    else:
-        res = translate(pat)
-    return re.compile(res).match
+
+def _compile_pattern(pat):
+    cache = _cacheb if isinstance(pat, bytes) else _cache
+    regex = cache.get(pat)
+    if regex is None:
+        if isinstance(pat, bytes):
+            pat_str = str(pat, 'ISO-8859-1')
+            res_str = translate(pat_str)
+            res = bytes(res_str, 'ISO-8859-1')
+        else:
+            res = translate(pat)
+        if len(cache) >= _MAXCACHE:
+            cache.clear()
+        cache[pat] = regex = re.compile(res)
+    return regex.match
+
 
 def filter(names, pat):
     """Return the subset of the list NAMES that match PAT."""
     result = []
     pat = os.path.normcase(pat)
-    match = _compile_pattern(pat, isinstance(pat, bytes))
+    match = _compile_pattern(pat)
     if os.path is posixpath:
         # normcase on posix is NOP. Optimize it away from the loop.
         for name in names:
@@ -61,13 +78,14 @@ def filter(names, pat):
                 result.append(name)
     return result
 
+
 def fnmatchcase(name, pat):
     """Test whether FILENAME matches PATTERN, including case.
 
     This is a version of fnmatch() which doesn't case-normalize
     its arguments.
     """
-    match = _compile_pattern(pat, isinstance(pat, bytes))
+    match = _compile_pattern(pat)
     return match(name) is not None