mercurial/match.py

revlog: use existing file handle when reading during _addrevision

_addrevision() may need to read from revlogs as part of computing
deltas. Previously, we would flush existing file handles and open
a new, short-lived file handle to perform the reading.

If we have an existing file handle, it seems logical to reuse it
for reading instead of opening a new file handle. This patch
makes that the new behavior.

After this patch, revlog files are only reopened when adding
revisions if the revlog is switched from inline to non-inline.

On Linux when unbundling a bundle of the mozilla-central repo, this
patch has the following impact on system call counts:

Call     Before     After       Delta
write    827,639    673,390   -154,249
open     700,103    684,089    -16,014
read      74,489     74,489          0
fstat    493,924    461,896    -32,028
close    249,131    233,117    -16,014
stat     242,001    242,001          0
lstat     18,676     18,676          0
lseek     20,268     20,268          0
ioctl     14,652     13,173     -1,479
TOTAL  3,180,758  2,930,679   -250,079

It's worth noting that many of the open() calls fail due to missing
files. That's why there are many more open() calls than close().

Despite the significant system call reduction, this change does not
seem to have a significant performance impact on Linux.

On Windows 10 (not a VM, on a SSD), this patch appears to reduce
unbundle time for mozilla-central from ~960s to ~920s. This isn't
as significant as I was hoping. But a decrease it is nonetheless.
Still, Windows unbundle performance is still >2x slower than Linux.

Despite the lack of significant gains, fewer system calls is fewer
system calls. If nothing else, this will narrow the focus of potential
areas to optimize in the future.

# match.py - filename matching
#
#  Copyright 2008, 2009 Matt Mackall <[e-mail]> 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.

from __future__ import absolute_import

import copy
import os
import re

from .i18n import _
from . import (
    pathutil,
    util,
)

propertycache = util.propertycache

def _rematcher(regex):
    '''compile the regexp with the best available regexp engine and return a
    matcher function'''
    m = util.re.compile(regex)
    try:
        # slightly faster, provided by facebook's re2 bindings
        return m.test_match
    except AttributeError:
        return m.match

def _expandsets(kindpats, ctx, listsubrepos):
    '''Returns the kindpats list with the 'set' patterns expanded.'''
    fset = set()
    other = []

    for kind, pat, source in kindpats:
        if kind == 'set':
            if not ctx:
                raise util.Abort("fileset expression with no context")
            s = ctx.getfileset(pat)
            fset.update(s)

            if listsubrepos:
                for subpath in ctx.substate:
                    s = ctx.sub(subpath).getfileset(pat)
                    fset.update(subpath + '/' + f for f in s)

            continue
        other.append((kind, pat, source))
    return fset, other

def _expandsubinclude(kindpats, root):
    '''Returns the list of subinclude matchers and the kindpats without the
    subincludes in it.'''
    relmatchers = []
    other = []

    for kind, pat, source in kindpats:
        if kind == 'subinclude':
            sourceroot = pathutil.dirname(util.normpath(source))
            pat = util.pconvert(pat)
            path = pathutil.join(sourceroot, pat)

            newroot = pathutil.dirname(path)
            relmatcher = match(newroot, '', [], ['include:%s' % path])

            prefix = pathutil.canonpath(root, root, newroot)
            if prefix:
                prefix += '/'
            relmatchers.append((prefix, relmatcher))
        else:
            other.append((kind, pat, source))

    return relmatchers, other

def _kindpatsalwaysmatch(kindpats):
    """"Checks whether the kindspats match everything, as e.g.
    'relpath:.' does.
    """
    for kind, pat, source in kindpats:
        if pat != '' or kind not in ['relpath', 'glob']:
            return False
    return True

class match(object):
    def __init__(self, root, cwd, patterns, include=[], exclude=[],
                 default='glob', exact=False, auditor=None, ctx=None,
                 listsubrepos=False, warn=None, badfn=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 (unless they are excluded)
        exclude - patterns to exclude (even if they are included)
        default - if a pattern in patterns has no explicit type, assume this one
        exact - patterns are actually filenames (include/exclude still apply)
        warn - optional function used for printing warnings
        badfn - optional bad() callback for this matcher instead of the default

        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
        'include:<path>' - a file of patterns to read and include
        'subinclude:<path>' - a file of patterns to match against files under
                              the same directory
        '<something>' - a pattern of the specified default type
        """

        self._root = root
        self._cwd = cwd
        self._files = [] # exact files and roots of patterns
        self._anypats = bool(include or exclude)
        self._always = False
        self._pathrestricted = bool(include or exclude or patterns)
        self._warn = warn
        self._includeroots = set()
        self._includedirs = set(['.'])
        self._excluderoots = set()

        if badfn is not None:
            self.bad = badfn

        matchfns = []
        if include:
            kindpats = self._normalize(include, 'glob', root, cwd, auditor)
            self.includepat, im = _buildmatch(ctx, kindpats, '(?:/|$)',
                                              listsubrepos, root)
            self._includeroots.update(_roots(kindpats))
            self._includedirs.update(util.dirs(self._includeroots))
            matchfns.append(im)
        if exclude:
            kindpats = self._normalize(exclude, 'glob', root, cwd, auditor)
            self.excludepat, em = _buildmatch(ctx, kindpats, '(?:/|$)',
                                              listsubrepos, root)
            if not _anypats(kindpats):
                self._excluderoots.update(_roots(kindpats))
            matchfns.append(lambda f: not em(f))
        if exact:
            if isinstance(patterns, list):
                self._files = patterns
            else:
                self._files = list(patterns)
            matchfns.append(self.exact)
        elif patterns:
            kindpats = self._normalize(patterns, default, root, cwd, auditor)
            if not _kindpatsalwaysmatch(kindpats):
                self._files = _roots(kindpats)
                self._anypats = self._anypats or _anypats(kindpats)
                self.patternspat, pm = _buildmatch(ctx, kindpats, '$',
                                                   listsubrepos, root)
                matchfns.append(pm)

        if not matchfns:
            m = util.always
            self._always = True
        elif len(matchfns) == 1:
            m = matchfns[0]
        else:
            def m(f):
                for matchfn in matchfns:
                    if not matchfn(f):
                        return False
                return True

        self.matchfn = m
        self._fileroots = set(self._files)

    def __call__(self, fn):
        return self.matchfn(fn)
    def __iter__(self):
        for f in self._files:
            yield f

    # Callbacks related to how the matcher is used by dirstate.walk.
    # Subscribers to these events must monkeypatch the matcher object.
    def bad(self, f, msg):
        '''Callback from dirstate.walk for each explicit file that can't be
        found/accessed, with an error message.'''
        pass

    # If an explicitdir is set, it will be called when an explicitly listed
    # directory is visited.
    explicitdir = None

    # If an traversedir is set, it will be called when a directory discovered
    # by recursive traversal is visited.
    traversedir = None

    def abs(self, f):
        '''Convert a repo path back to path that is relative to the root of the
        matcher.'''
        return f

    def rel(self, f):
        '''Convert repo path back to path that is relative to cwd of matcher.'''
        return util.pathto(self._root, self._cwd, f)

    def uipath(self, f):
        '''Convert repo path to a display path.  If patterns or -I/-X were used
        to create this matcher, the display path will be relative to cwd.
        Otherwise it is relative to the root of the repo.'''
        return (self._pathrestricted and self.rel(f)) or self.abs(f)

    def files(self):
        '''Explicitly listed files or patterns or roots:
        if no patterns or .always(): empty list,
        if exact: list exact files,
        if not .anypats(): list all files and dirs,
        else: optimal roots'''
        return self._files

    @propertycache
    def _dirs(self):
        return set(util.dirs(self._fileroots)) | set(['.'])

    def visitdir(self, dir):
        '''Decides whether a directory should be visited based on whether it
        has potential matches in it or one of its subdirectories. This is
        based on the match's primary, included, and excluded patterns.

        This function's behavior is undefined if it has returned False for
        one of the dir's parent directories.
        '''
        if dir in self._excluderoots:
            return False
        if (self._includeroots and
            '.' not in self._includeroots and
            dir not in self._includeroots and
            dir not in self._includedirs and
            not any(parent in self._includeroots
                    for parent in util.finddirs(dir))):
            return False
        return (not self._fileroots or
                '.' in self._fileroots or
                dir in self._fileroots or
                dir in self._dirs or
                any(parentdir in self._fileroots
                    for parentdir in util.finddirs(dir)))

    def exact(self, f):
        '''Returns True if f is in .files().'''
        return f in self._fileroots

    def anypats(self):
        '''Matcher uses patterns or include/exclude.'''
        return self._anypats

    def always(self):
        '''Matcher will match everything and .files() will be empty
        - optimization might be possible and necessary.'''
        return self._always

    def ispartial(self):
        '''True if the matcher won't always match.

        Although it's just the inverse of _always in this implementation,
        an extenion such as narrowhg might make it return something
        slightly different.'''
        return not self._always

    def isexact(self):
        return self.matchfn == self.exact

    def prefix(self):
        return not self.always() and not self.isexact() and not self.anypats()

    def _normalize(self, patterns, default, root, cwd, auditor):
        '''Convert 'kind:pat' from the patterns list to tuples with kind and
        normalized and rooted patterns and with listfiles expanded.'''
        kindpats = []
        for kind, pat in [_patsplit(p, default) for p in patterns]:
            if kind in ('glob', 'relpath'):
                pat = pathutil.canonpath(root, cwd, pat, auditor)
            elif kind in ('relglob', 'path'):
                pat = util.normpath(pat)
            elif kind in ('listfile', 'listfile0'):
                try:
                    files = util.readfile(pat)
                    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)") % pat)
                for k, p, source in self._normalize(files, default, root, cwd,
                                                    auditor):
                    kindpats.append((k, p, pat))
                continue
            elif kind == 'include':
                try:
                    fullpath = os.path.join(root, util.localpath(pat))
                    includepats = readpatternfile(fullpath, self._warn)
                    for k, p, source in self._normalize(includepats, default,
                                                        root, cwd, auditor):
                        kindpats.append((k, p, source or pat))
                except util.Abort as inst:
                    raise util.Abort('%s: %s' % (pat, inst[0]))
                except IOError as inst:
                    if self._warn:
                        self._warn(_("skipping unreadable pattern file "
                                     "'%s': %s\n") % (pat, inst.strerror))
                continue
            # else: re or relre - which cannot be normalized
            kindpats.append((kind, pat, ''))
        return kindpats

def exact(root, cwd, files, badfn=None):
    return match(root, cwd, files, exact=True, badfn=badfn)

def always(root, cwd):
    return match(root, cwd, [])

def badmatch(match, badfn):
    """Make a copy of the given matcher, replacing its bad method with the given
    one.
    """
    m = copy.copy(match)
    m.bad = badfn
    return m

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
    >>> util.pconvert(m2.rel('b.txt'))
    'sub/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
    >>> m2.abs('c.txt')
    'sub/c.txt'
    """

    def __init__(self, path, matcher):
        self._root = matcher._root
        self._cwd = matcher._cwd
        self._path = path
        self._matcher = matcher
        self._always = matcher._always
        self._pathrestricted = matcher._pathrestricted

        self._files = [f[len(path) + 1:] for f in matcher._files
                       if f.startswith(path + "/")]

        # If the parent repo had a path to this subrepo and no patterns are
        # specified, this submatcher always matches.
        if not self._always and not matcher._anypats:
            self._always = any(f == path for f in matcher._files)

        self._anypats = matcher._anypats
        self.matchfn = lambda fn: matcher.matchfn(self._path + "/" + fn)
        self._fileroots = set(self._files)

    def abs(self, f):
        return self._matcher.abs(self._path + "/" + f)

    def bad(self, f, msg):
        self._matcher.bad(self._path + "/" + f, msg)

    def rel(self, f):
        return self._matcher.rel(self._path + "/" + f)

class icasefsmatcher(match):
    """A matcher for wdir on case insensitive filesystems, which normalizes the
    given patterns to the case in the filesystem.
    """

    def __init__(self, root, cwd, patterns, include, exclude, default, auditor,
                 ctx, listsubrepos=False, badfn=None):
        init = super(icasefsmatcher, self).__init__
        self._dirstate = ctx.repo().dirstate
        self._dsnormalize = self._dirstate.normalize

        init(root, cwd, patterns, include, exclude, default, auditor=auditor,
             ctx=ctx, listsubrepos=listsubrepos, badfn=badfn)

        # m.exact(file) must be based off of the actual user input, otherwise
        # inexact case matches are treated as exact, and not noted without -v.
        if self._files:
            self._fileroots = set(_roots(self._kp))

    def _normalize(self, patterns, default, root, cwd, auditor):
        self._kp = super(icasefsmatcher, self)._normalize(patterns, default,
                                                          root, cwd, auditor)
        kindpats = []
        for kind, pats, source in self._kp:
            if kind not in ('re', 'relre'):  # regex can't be normalized
                p = pats
                pats = self._dsnormalize(pats)

                # Preserve the original to handle a case only rename.
                if p != pats and p in self._dirstate:
                    kindpats.append((kind, p, source))

            kindpats.append((kind, pats, source))
        return kindpats

def patkind(pattern, default=None):
    '''If pattern is 'kind:pat' with a known kind, return kind.'''
    return _patsplit(pattern, default)[0]

def _patsplit(pattern, default):
    """Split a string into the optional pattern kind prefix and the actual
    pattern."""
    if ':' in pattern:
        kind, pat = pattern.split(':', 1)
        if kind in ('re', 'glob', 'path', 'relglob', 'relpath', 'relre',
                    'listfile', 'listfile0', 'set', 'include', 'subinclude'):
            return kind, pat
    return default, pattern

def _globre(pat):
    r'''Convert an extended glob string to a regexp string.

    >>> print _globre(r'?')
    .
    >>> print _globre(r'*')
    [^/]*
    >>> print _globre(r'**')
    .*
    >>> print _globre(r'**/a')
    (?:.*/)?a
    >>> print _globre(r'a/**/b')
    a\/(?:.*/)?b
    >>> print _globre(r'[a*?!^][^b][!c]')
    [a*?!^][\^b][^c]
    >>> print _globre(r'{a,b}')
    (?:a|b)
    >>> print _globre(r'.\*\?')
    \.\*\?
    '''
    i, n = 0, len(pat)
    res = ''
    group = 0
    escape = util.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
                if peek() == '/':
                    i += 1
                    res += '(?:.*/)?'
                else:
                    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, pat, globsuffix):
    '''Convert a (normalized) pattern of any kind into a regular expression.
    globsuffix is appended to the regexp of globs.'''
    if not pat:
        return ''
    if kind == 're':
        return pat
    if kind == 'path':
        if pat == '.':
            return ''
        return '^' + util.re.escape(pat) + '(?:/|$)'
    if kind == 'relglob':
        return '(?:|.*/)' + _globre(pat) + globsuffix
    if kind == 'relpath':
        return util.re.escape(pat) + '(?:/|$)'
    if kind == 'relre':
        if pat.startswith('^'):
            return pat
        return '.*' + pat
    return _globre(pat) + globsuffix

def _buildmatch(ctx, kindpats, globsuffix, listsubrepos, root):
    '''Return regexp string and a matcher function for kindpats.
    globsuffix is appended to the regexp of globs.'''
    matchfuncs = []

    subincludes, kindpats = _expandsubinclude(kindpats, root)
    if subincludes:
        def matchsubinclude(f):
            for prefix, mf in subincludes:
                if f.startswith(prefix) and mf(f[len(prefix):]):
                    return True
            return False
        matchfuncs.append(matchsubinclude)

    fset, kindpats = _expandsets(kindpats, ctx, listsubrepos)
    if fset:
        matchfuncs.append(fset.__contains__)

    regex = ''
    if kindpats:
        regex, mf = _buildregexmatch(kindpats, globsuffix)
        matchfuncs.append(mf)

    if len(matchfuncs) == 1:
        return regex, matchfuncs[0]
    else:
        return regex, lambda f: any(mf(f) for mf in matchfuncs)

def _buildregexmatch(kindpats, globsuffix):
    """Build a match function from a list of kinds and kindpats,
    return regexp string and a matcher function."""
    try:
        regex = '(?:%s)' % '|'.join([_regex(k, p, globsuffix)
                                     for (k, p, s) in kindpats])
        if len(regex) > 20000:
            raise OverflowError
        return regex, _rematcher(regex)
    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(kindpats)
        if l < 2:
            raise
        regexa, a = _buildregexmatch(kindpats[:l//2], globsuffix)
        regexb, b = _buildregexmatch(kindpats[l//2:], globsuffix)
        return regex, lambda s: a(s) or b(s)
    except re.error:
        for k, p, s in kindpats:
            try:
                _rematcher('(?:%s)' % _regex(k, p, globsuffix))
            except re.error:
                if s:
                    raise util.Abort(_("%s: invalid pattern (%s): %s") %
                                     (s, k, p))
                else:
                    raise util.Abort(_("invalid pattern (%s): %s") % (k, p))
        raise util.Abort(_("invalid pattern"))

def _roots(kindpats):
    '''return roots and exact explicitly listed files from patterns

    >>> _roots([('glob', 'g/*', ''), ('glob', 'g', ''), ('glob', 'g*', '')])
    ['g', 'g', '.']
    >>> _roots([('relpath', 'r', ''), ('path', 'p/p', ''), ('path', '', '')])
    ['r', 'p/p', '.']
    >>> _roots([('relglob', 'rg*', ''), ('re', 're/', ''), ('relre', 'rr', '')])
    ['.', '.', '.']
    '''
    r = []
    for kind, pat, source in kindpats:
        if kind == 'glob': # find the non-glob prefix
            root = []
            for p in pat.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(pat or '.')
        else: # relglob, re, relre
            r.append('.')
    return r

def _anypats(kindpats):
    for kind, pat, source in kindpats:
        if kind in ('glob', 're', 'relglob', 'relre', 'set'):
            return True

_commentre = None

def readpatternfile(filepath, warn):
    '''parse a pattern file, returning a list of
    patterns. These patterns should be given to compile()
    to be validated and converted into a match function.

    trailing white space is dropped.
    the escape character is backslash.
    comments start with #.
    empty lines are skipped.

    lines can be of the following formats:

    syntax: regexp # defaults following lines to non-rooted regexps
    syntax: glob   # defaults following lines to non-rooted globs
    re:pattern     # non-rooted regular expression
    glob:pattern   # non-rooted glob
    pattern        # pattern of the current default type'''

    syntaxes = {'re': 'relre:', 'regexp': 'relre:', 'glob': 'relglob:',
                'include': 'include', 'subinclude': 'subinclude'}
    syntax = 'relre:'
    patterns = []

    fp = open(filepath)
    for line in fp:
        if "#" in line:
            global _commentre
            if not _commentre:
                _commentre = re.compile(r'((^|[^\\])(\\\\)*)#.*')
            # remove comments prefixed by an even number of escapes
            line = _commentre.sub(r'\1', line)
            # fixup properly escaped comments that survived the above
            line = line.replace("\\#", "#")
        line = line.rstrip()
        if not line:
            continue

        if line.startswith('syntax:'):
            s = line[7:].strip()
            try:
                syntax = syntaxes[s]
            except KeyError:
                if warn:
                    warn(_("%s: ignoring invalid syntax '%s'\n") %
                         (filepath, s))
            continue

        linesyntax = syntax
        for s, rels in syntaxes.iteritems():
            if line.startswith(rels):
                linesyntax = rels
                line = line[len(rels):]
                break
            elif line.startswith(s+':'):
                linesyntax = rels
                line = line[len(s) + 1:]
                break
        patterns.append(linesyntax + line)
    fp.close()
    return patterns