# keyword.py - keyword expansion for mercurial

'''keyword expansion hack against the grain of a DSCM

This extension lets you expand RCS/CVS-like keywords in a Mercurial

repository.

There are many good reasons why this is not needed in a distributed

SCM, still it may be useful in very small projects based on single

files (like LaTeX packages), that are mostly addressed to an audience

not running a version control system.

Supported keywords are (changeset 000000000000):

    $Revision: 000000000000 $

    $Author: Your Name <address@example.com> $

    $Date: %a %b %d %H:%M:%S %Y %z $

    $RCSFile: basename,v $

    $Source: /path/to/basename,v $

    $Id: basename,v 000000000000 %Y-%m-%d %H:%M:%S %z shortname $

    $Header: /path/to/basename,v 000000000000 %Y-%m-%d %H:%M:%S %z shortname $

The extension, according to its hackish nature, is a hybrid and consists

actually in 2 parts:

    1. pure extension code (reposetup) that is triggered on checkout and

       logging of changes.

    2. a pretxncommit hook (hgrc (5)) that expands keywords immediately

       at commit time in the working directory.

Simple setup in hgrc:

    # enable extension

    hgext.keyword =

    # filename patterns for expansion are configured in this section

    [keyword]

    *.sty = expand

    ...

    # set up pretxncommit hook

    [hooks]

    pretxncommit =

    pretxncommit.keyword = python:hgext.keyword.pretxnkw

'''

from mercurial.i18n import _

from mercurial import context, util

import os.path, re

re_kw = re.compile(

        r'\$(Id|Header|Author|Date|Revision|RCSFile|Source)[^$]*?\$')

def kwexpand(matchobj, repo, path, changeid=None, fileid=None, filelog=None):

    '''Called by kwfilelog.read and pretxnkw.

    Sets supported keywords as local variables and evaluates them to

    their expansion if matchobj is equal to string representation.'''

    c = context.filectx(repo, path,

            changeid=changeid, fileid=fileid, filelog=filelog)

    date = c.date()

    Revision = c.changectx()

    Author = c.user()

    RCSFile = os.path.basename(path)+',v'

    Source = repo.wjoin(path)+',v'

    Date = util.datestr(date=date)

    revdateauth = '%s %s %s' % (Revision,

            util.datestr(date=date, format=util.defaultdateformats[0]),

            util.shortuser(Author))

    Header = '%s %s' % (Source, revdateauth)

    Id = '%s %s' % (RCSFile, revdateauth)

    return '$%s: %s $' % (matchobj.group(1), eval(matchobj.group(1)))

def kwfmatchers(ui, repo):

    '''Returns filename matchers from ui keyword section.'''

    return [util.matcher(repo.root, '', [pat], [], [])[1]

            for pat, opt in ui.configitems('keyword')

            if opt == 'expand']

def reposetup(ui, repo):

    from mercurial import filelog, revlog

    if not repo.local():

        return

    class kwrepo(repo.__class__):

        def file(self, f):

            if f[0] == '/':

                f = f[1:]

            return filelog.filelog(self.sopener, f, self, self.revlogversion)

    class kwfilelog(filelog.filelog):

        def __init__(self, opener, path, repo,

                     defversion=revlog.REVLOG_DEFAULT_VERSION):

            super(kwfilelog, self).__init__(opener, path, defversion)

            self._repo = repo

            self._path = path

        def read(self, node):

            data = super(kwfilelog, self).read(node)

            if not self._path.startswith('.hg') and not util.binary(data):

                for mf in kwfmatchers(ui, self._repo):

                    if mf(self._path):

                        ui.debug(_('expanding keywords in %s\n' % self._path))

                        return re_kw.sub(lambda m:

                                kwexpand(m, self._repo, self._path,

                                    fileid=node, filelog=self),

                                data)

            return data

        def size(self, rev):

            '''Overrides filelog's size() to use kwfilelog.read().'''

            node = revlog.node(self, rev)

            if super(kwfilelog, self).renamed(node):

                return len(self.read(node))

            return revlog.size(self, rev)

        def cmp(self, node, text):

            '''Overrides filelog's cmp() to use kwfilelog.read().'''

            if super(kwfilelog, self).renamed(node):

                t2 = self.read(node)

                return t2 != text

    filelog.filelog = kwfilelog

    repo.__class__ = kwrepo

def pretxnkw(ui, repo, hooktype, **args):

    '''pretxncommit hook that collects candidates for keyword expansion

    on commit and expands keywords in working dir.'''

    from mercurial import cmdutil, commands

    import sys

    if hooktype != 'pretxncommit':

        return True

    cmd, sysargs, globalopts, cmdopts = commands.parse(ui, sys.argv[1:])[1:]

    if repr(cmd).split()[1] in ('tag', 'import_'):

        return False

    files, match, anypats = cmdutil.matchpats(repo, sysargs, cmdopts)

    modified, added = repo.status(files=files, match=match)[:2]

    candidates = [f for f in modified + added if not f.startswith('.hg')]

    if not candidates:

        return False

    fmatchers = kwfmatchers(ui, repo)

    for f in candidates:

        for mf in fmatchers:

            if mf(f):

                data = repo.wfile(f).read()

                if not util.binary(data):

                    data, kwct = re_kw.subn(lambda m:

                            kwexpand(m, repo, f, changeid=args['node']),

                            data)

                    if kwct:

                        ui.debug(_('overwriting %s expanding keywords\n' % f))

                        repo.wfile(f, 'w').write(data)

                break