Issue #16564: Fixed a performance regression relative to Python 3.1 in the
caching of compiled regular expressions.
diff --git a/Lib/re.py b/Lib/re.py
index 85c5a57..b910606 100644
--- a/Lib/re.py
+++ b/Lib/re.py
@@ -215,8 +215,8 @@
def purge():
"Clear the regular expression caches"
- _compile_typed.cache_clear()
- _compile_repl.cache_clear()
+ _cache.clear()
+ _cache_repl.clear()
def template(pattern, flags=0):
"Compile a template pattern, returning a pattern object"
@@ -257,14 +257,19 @@
# --------------------------------------------------------------------
# internals
+_cache = {}
+_cache_repl = {}
+
_pattern_type = type(sre_compile.compile("", 0))
-def _compile(pattern, flags):
- return _compile_typed(type(pattern), pattern, flags)
+_MAXCACHE = 512
-@functools.lru_cache(maxsize=500)
-def _compile_typed(text_bytes_type, pattern, flags):
+def _compile(pattern, flags):
# internal: compile pattern
+ try:
+ return _cache[type(pattern), pattern, flags]
+ except KeyError:
+ pass
if isinstance(pattern, _pattern_type):
if flags:
raise ValueError(
@@ -272,12 +277,23 @@
return pattern
if not sre_compile.isstring(pattern):
raise TypeError("first argument must be string or compiled pattern")
- return sre_compile.compile(pattern, flags)
+ p = sre_compile.compile(pattern, flags)
+ if len(_cache) >= _MAXCACHE:
+ _cache.clear()
+ _cache[type(pattern), pattern, flags] = p
+ return p
-@functools.lru_cache(maxsize=500)
def _compile_repl(repl, pattern):
# internal: compile replacement pattern
- return sre_parse.parse_template(repl, pattern)
+ try:
+ return _cache_repl[repl, pattern]
+ except KeyError:
+ pass
+ p = sre_parse.parse_template(repl, pattern)
+ if len(_cache_repl) >= _MAXCACHE:
+ _cache_repl.clear()
+ _cache_repl[repl, pattern] = p
+ return p
def _expand(pattern, match, template):
# internal: match.expand implementation hook