mercurial/match.py

parsers: avoid pointer aliasing

Newer versions of GCC have aggressive pointer alias optimizations that
might get fooled by our pointer manipulations. These issues shouldn't
be encountered in practice because distutils compiles extensions with
-fno-strict-alias but the code was not valid according to the standard.

# 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.

import re
import scmutil, util, fileset
from i18n import _

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 canonroot
        '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._ctx = None
        self._root = root
        self._cwd = cwd
        self._files = []
        self._anypats = bool(include or exclude)
        self._ctx = ctx

        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:
            self._files = 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.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

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, [])

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._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, re.compile(pat).match
    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:
                re.compile('(?:%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'):
            return True