# 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 util, pathutil
from i18n import _

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):
    '''Returns the kindpats list with the 'set' patterns expanded.'''
    fset = set()
    other = []

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

def _kindpatsalwaysmatch(kindpats):
    """"Checks whether the kindspats match everything, as e.g.
    'relpath:.' does.
    """
    for kind, pat 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):
        """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)

        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 = [] # exact files and roots of patterns
        self._anypats = bool(include or exclude)
        self._always = False
        self._pathrestricted = bool(include or exclude or patterns)

        matchfns = []
        if include:
            kindpats = _normalize(include, 'glob', root, cwd, auditor)
            self.includepat, im = _buildmatch(ctx, kindpats, '(?:/|$)')
            matchfns.append(im)
        if exclude:
            kindpats = _normalize(exclude, 'glob', root, cwd, auditor)
            self.excludepat, em = _buildmatch(ctx, kindpats, '(?:/|$)')
            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 = _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, '$')
                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._fmap = 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._fmap)) | set(['.'])

    def visitdir(self, dir):
        '''Helps while traversing a directory tree. Returns the string 'all' if
        the given directory and all subdirectories should be visited. Otherwise
        returns True or False indicating whether the given directory should be
        visited. If 'all' is returned, calling this method on a subdirectory
        gives an undefined result.'''
        if not self._fmap or self.exact(dir):
            return 'all'
        return dir in self._dirs

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

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

def exact(root, cwd, files):
    return match(root, cwd, files, exact=True)

def always(root, cwd):
    return match(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
    >>> 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 + "/")]
        self._anypats = matcher._anypats
        self.matchfn = lambda fn: matcher.matchfn(self._path + "/" + fn)
        self._fmap = 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)

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'):
            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':
        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):
    '''Return regexp string and a matcher function for kindpats.
    globsuffix is appended to the regexp of globs.'''
    fset, kindpats = _expandsets(kindpats, ctx)
    if not kindpats:
        return "", fset.__contains__

    regex, mf = _buildregexmatch(kindpats, globsuffix)
    if fset:
        return regex, lambda f: f in fset or mf(f)
    return regex, mf

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) 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 in kindpats:
            try:
                _rematcher('(?:%s)' % _regex(k, p, globsuffix))
            except re.error:
                raise util.Abort(_("invalid pattern (%s): %s") % (k, p))
        raise util.Abort(_("invalid pattern"))

def _normalize(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)
            kindpats += _normalize(files, default, root, cwd, auditor)
            continue
        # else: re or relre - which cannot be normalized
        kindpats.append((kind, pat))
    return kindpats

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 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 in kindpats:
        if kind in ('glob', 're', 'relglob', 'relre', 'set'):
            return True