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parsers: a C implementation of the new ancestors algorithm...
parsers: a C implementation of the new ancestors algorithm The performance of both the old and new Python ancestor algorithms depends on the number of revs they need to traverse. Although the new algorithm performs far better than the old when revs are numerically and topologically close, both algorithms become slow under other circumstances, taking up to 1.8 seconds to give answers in a Linux kernel repo. This C implementation of the new algorithm is a fairly straightforward transliteration. The only corner case of interest is that it raises an OverflowError if the number of GCA candidates found during the first pass is greater than 24, to avoid the dual perils of fixnum overflow and trying to allocate too much memory. (If this exception is raised, the Python implementation is used instead.) Performance numbers are good: in a Linux kernel repo, time for "hg debugancestors" on two distant revs (24bf01de7537 and c2a8808f5943) is as follows: Old Python: 0.36 sec New Python: 0.42 sec New C: 0.02 sec For a case where the new algorithm should perform well: Old Python: 1.84 sec New Python: 0.07 sec New C: measures as zero when using --time (This commit includes a paranoid cross-check to ensure that the Python and C implementations give identical answers. The above performance numbers were measured with that check disabled.)

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match.py
354 lines | 10.7 KiB | text/x-python | PythonLexer
# match.py - filename matching
#
# Copyright 2008, 2009 Matt Mackall <mpm@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import re
import scmutil, util, fileset
from i18n import _
def _rematcher(pat):
m = util.compilere(pat)
try:
# slightly faster, provided by facebook's re2 bindings
return m.test_match
except AttributeError:
return m.match
def _expandsets(pats, ctx):
'''convert set: patterns into a list of files in the given context'''
fset = set()
other = []
for kind, expr in pats:
if kind == 'set':
if not ctx:
raise util.Abort("fileset expression with no context")
s = fileset.getfileset(ctx, expr)
fset.update(s)
continue
other.append((kind, expr))
return fset, other
class match(object):
def __init__(self, root, cwd, patterns, include=[], exclude=[],
default='glob', exact=False, auditor=None, ctx=None):
"""build an object to match a set of file patterns
arguments:
root - the canonical root of the tree you're matching against
cwd - the current working directory, if relevant
patterns - patterns to find
include - patterns to include
exclude - patterns to exclude
default - if a pattern in names has no explicit type, assume this one
exact - patterns are actually literals
a pattern is one of:
'glob:<glob>' - a glob relative to cwd
're:<regexp>' - a regular expression
'path:<path>' - a path relative to repository root
'relglob:<glob>' - an unrooted glob (*.c matches C files in all dirs)
'relpath:<path>' - a path relative to cwd
'relre:<regexp>' - a regexp that needn't match the start of a name
'set:<fileset>' - a fileset expression
'<something>' - a pattern of the specified default type
"""
self._root = root
self._cwd = cwd
self._files = []
self._anypats = bool(include or exclude)
self._ctx = ctx
self._always = False
if include:
pats = _normalize(include, 'glob', root, cwd, auditor)
self.includepat, im = _buildmatch(ctx, pats, '(?:/|$)')
if exclude:
pats = _normalize(exclude, 'glob', root, cwd, auditor)
self.excludepat, em = _buildmatch(ctx, pats, '(?:/|$)')
if exact:
if isinstance(patterns, list):
self._files = patterns
else:
self._files = list(patterns)
pm = self.exact
elif patterns:
pats = _normalize(patterns, default, root, cwd, auditor)
self._files = _roots(pats)
self._anypats = self._anypats or _anypats(pats)
self.patternspat, pm = _buildmatch(ctx, pats, '$')
if patterns or exact:
if include:
if exclude:
m = lambda f: im(f) and not em(f) and pm(f)
else:
m = lambda f: im(f) and pm(f)
else:
if exclude:
m = lambda f: not em(f) and pm(f)
else:
m = pm
else:
if include:
if exclude:
m = lambda f: im(f) and not em(f)
else:
m = im
else:
if exclude:
m = lambda f: not em(f)
else:
m = lambda f: True
self._always = True
self.matchfn = m
self._fmap = set(self._files)
def __call__(self, fn):
return self.matchfn(fn)
def __iter__(self):
for f in self._files:
yield f
def bad(self, f, msg):
'''callback for each explicit file that can't be
found/accessed, with an error message
'''
pass
def dir(self, f):
pass
def missing(self, f):
pass
def exact(self, f):
return f in self._fmap
def rel(self, f):
return util.pathto(self._root, self._cwd, f)
def files(self):
return self._files
def anypats(self):
return self._anypats
def always(self):
return self._always
class exact(match):
def __init__(self, root, cwd, files):
match.__init__(self, root, cwd, files, exact = True)
class always(match):
def __init__(self, root, cwd):
match.__init__(self, root, cwd, [])
self._always = True
class narrowmatcher(match):
"""Adapt a matcher to work on a subdirectory only.
The paths are remapped to remove/insert the path as needed:
>>> m1 = match('root', '', ['a.txt', 'sub/b.txt'])
>>> m2 = narrowmatcher('sub', m1)
>>> bool(m2('a.txt'))
False
>>> bool(m2('b.txt'))
True
>>> bool(m2.matchfn('a.txt'))
False
>>> bool(m2.matchfn('b.txt'))
True
>>> m2.files()
['b.txt']
>>> m2.exact('b.txt')
True
>>> m2.rel('b.txt')
'b.txt'
>>> def bad(f, msg):
... print "%s: %s" % (f, msg)
>>> m1.bad = bad
>>> m2.bad('x.txt', 'No such file')
sub/x.txt: No such file
"""
def __init__(self, path, matcher):
self._root = matcher._root
self._cwd = matcher._cwd
self._path = path
self._matcher = matcher
self._always = matcher._always
self._files = [f[len(path) + 1:] for f in matcher._files
if f.startswith(path + "/")]
self._anypats = matcher._anypats
self.matchfn = lambda fn: matcher.matchfn(self._path + "/" + fn)
self._fmap = set(self._files)
def bad(self, f, msg):
self._matcher.bad(self._path + "/" + f, msg)
def patkind(pat):
return _patsplit(pat, None)[0]
def _patsplit(pat, default):
"""Split a string into an optional pattern kind prefix and the
actual pattern."""
if ':' in pat:
kind, val = pat.split(':', 1)
if kind in ('re', 'glob', 'path', 'relglob', 'relpath', 'relre',
'listfile', 'listfile0', 'set'):
return kind, val
return default, pat
def _globre(pat):
"convert a glob pattern into a regexp"
i, n = 0, len(pat)
res = ''
group = 0
escape = re.escape
def peek():
return i < n and pat[i]
while i < n:
c = pat[i]
i += 1
if c not in '*?[{},\\':
res += escape(c)
elif c == '*':
if peek() == '*':
i += 1
res += '.*'
else:
res += '[^/]*'
elif c == '?':
res += '.'
elif c == '[':
j = i
if j < n and pat[j] in '!]':
j += 1
while j < n and pat[j] != ']':
j += 1
if j >= n:
res += '\\['
else:
stuff = pat[i:j].replace('\\','\\\\')
i = j + 1
if stuff[0] == '!':
stuff = '^' + stuff[1:]
elif stuff[0] == '^':
stuff = '\\' + stuff
res = '%s[%s]' % (res, stuff)
elif c == '{':
group += 1
res += '(?:'
elif c == '}' and group:
res += ')'
group -= 1
elif c == ',' and group:
res += '|'
elif c == '\\':
p = peek()
if p:
i += 1
res += escape(p)
else:
res += escape(c)
else:
res += escape(c)
return res
def _regex(kind, name, tail):
'''convert a pattern into a regular expression'''
if not name:
return ''
if kind == 're':
return name
elif kind == 'path':
return '^' + re.escape(name) + '(?:/|$)'
elif kind == 'relglob':
return '(?:|.*/)' + _globre(name) + tail
elif kind == 'relpath':
return re.escape(name) + '(?:/|$)'
elif kind == 'relre':
if name.startswith('^'):
return name
return '.*' + name
return _globre(name) + tail
def _buildmatch(ctx, pats, tail):
fset, pats = _expandsets(pats, ctx)
if not pats:
return "", fset.__contains__
pat, mf = _buildregexmatch(pats, tail)
if fset:
return pat, lambda f: f in fset or mf(f)
return pat, mf
def _buildregexmatch(pats, tail):
"""build a matching function from a set of patterns"""
try:
pat = '(?:%s)' % '|'.join([_regex(k, p, tail) for (k, p) in pats])
if len(pat) > 20000:
raise OverflowError
return pat, _rematcher(pat)
except OverflowError:
# We're using a Python with a tiny regex engine and we
# made it explode, so we'll divide the pattern list in two
# until it works
l = len(pats)
if l < 2:
raise
pata, a = _buildregexmatch(pats[:l//2], tail)
patb, b = _buildregexmatch(pats[l//2:], tail)
return pat, lambda s: a(s) or b(s)
except re.error:
for k, p in pats:
try:
_rematcher('(?:%s)' % _regex(k, p, tail))
except re.error:
raise util.Abort(_("invalid pattern (%s): %s") % (k, p))
raise util.Abort(_("invalid pattern"))
def _normalize(names, default, root, cwd, auditor):
pats = []
for kind, name in [_patsplit(p, default) for p in names]:
if kind in ('glob', 'relpath'):
name = scmutil.canonpath(root, cwd, name, auditor)
elif kind in ('relglob', 'path'):
name = util.normpath(name)
elif kind in ('listfile', 'listfile0'):
try:
files = util.readfile(name)
if kind == 'listfile0':
files = files.split('\0')
else:
files = files.splitlines()
files = [f for f in files if f]
except EnvironmentError:
raise util.Abort(_("unable to read file list (%s)") % name)
pats += _normalize(files, default, root, cwd, auditor)
continue
pats.append((kind, name))
return pats
def _roots(patterns):
r = []
for kind, name in patterns:
if kind == 'glob': # find the non-glob prefix
root = []
for p in name.split('/'):
if '[' in p or '{' in p or '*' in p or '?' in p:
break
root.append(p)
r.append('/'.join(root) or '.')
elif kind in ('relpath', 'path'):
r.append(name or '.')
elif kind == 'relglob':
r.append('.')
return r
def _anypats(patterns):
for kind, name in patterns:
if kind in ('glob', 're', 'relglob', 'relre', 'set'):
return True