# keyword.py - keyword expansion for Mercurial

#

# Copyright 2007 Christian Ebert <blacktrash@gmx.net>

#

# This software may be used and distributed according to the terms

# of the GNU General Public License, incorporated herein by reference.

#

# $Id$

# 

# Keyword expansion hack against the grain of a DSCM

# 

# 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.

# 

# For in-depth discussion refer to

# <http://www.selenic.com/mercurial/wiki/index.cgi/KeywordPlan>.

#

# Keyword expansion is based on Mercurial's changeset template mappings.

# The extension provides an additional UTC-date filter ({date|utcdate}).

#

# The user has the choice either to create his own keywords and their

# expansions or to use the CVS-like default ones.

# 

# Default $keywords$ and their $keyword: substition $ are:

#     Revision: changeset id

#     Author:   username

#     Date:     %Y/%m/%d %H:%M:%S [UTC]

#     RCSFile:  basename,v

#     Source:   /path/to/basename,v

#     Id:       basename,v csetid %Y/%m/%d %H:%M:%S username

#     Header:   /path/to/basename,v csetid %Y/%m/%d %H:%M:%S username

# 

# Expansions spanning more than one line are truncated to their first line.

# Incremental expansion (like CVS' $Log$) is not supported.

# 

# Simple setup in hgrc:

# 

#     # enable extension

#     keyword = /full/path/to/keyword.py

#     # or, if script in hgext folder:

#     # hgext.keyword =

#     

#     # filename patterns for expansion are configured in this section

#     # files matching patterns with value 'ignore' are ignored

#     [keyword]

#     **.py =

#     x* = ignore

#     ...

#     # in case you prefer your own keyword maps over the cvs-like defaults:

#     [keywordmaps]

#     HGdate = {date|rfc822date}

#     lastlog = {desc} ## same as {desc|firstline} in this context

#     checked in by = {author}

#     ...

'''keyword expansion in local repositories

This extension expands RCS/CVS-like or self-customized keywords in

the text files selected by your configuration.

Keywords are only expanded in local repositories and not logged by

Mercurial internally. The mechanism can be regarded as a convenience

for the current user and may be turned off anytime.

Substitution takes place on every commit and update of the working

repository.

Configuration is done in the [keyword] and [keywordmaps] sections of

hgrc files.

'''

from mercurial.i18n import gettext as _

# above line for backwards compatibility; can be changed to

#   from mercurial.i18n import _

# some day

from mercurial import context, filelog, revlog

from mercurial import commands, cmdutil, templater, util

from mercurial.node import bin

import os.path, re, sys, time

deftemplates = {

        'Revision': '{node|short}',

        'Author': '{author|user}',

        'Date': '{date|utcdate}',

        'RCSFile': '{file|basename},v',

        'Source': '{root}/{file},v',

        'Id': '{file|basename},v {node|short} {date|utcdate} {author|user}',

        'Header': '{root}/{file},v {node|short} {date|utcdate} {author|user}',

        }

def utcdate(date):

    '''Returns hgdate in cvs-like UTC format.'''

    return time.strftime('%Y/%m/%d %H:%M:%S', time.gmtime(date[0]))

def getmodulename():

    '''Makes sure pretxncommit-hook can import keyword module

    regardless of where its located.'''

    for k, v in sys.modules.iteritems():

        if v is None:

            continue

        if not hasattr(v, '__file__'):

            continue

        if v.__file__.startswith(__file__):

            return k

    else:

        sys.path.insert(0, os.path.abspath(os.path.dirname(__file__)))

        return os.path.splitext(os.path.basename(__file__))[0]

class kwtemplater(object):

    '''

    Sets up keyword templates, corresponding keyword regex, and

    provides keyword expansion function.

    '''

    def __init__(self, ui, repo):

        self.ui = ui

        self.repo = repo

        self.templates = dict(ui.configitems('keywordmaps')) or deftemplates

        self.re_kw = re.compile(r'\$(%s)[^$]*?\$' %

                '|'.join(re.escape(k) for k in self.templates.keys()))

        templater.common_filters['utcdate'] = utcdate

        self.t = cmdutil.changeset_templater(ui, repo, False, '', False)

    def expand(self, mobj, path, node):

        '''Expands keyword using corresponding template.'''

        kw = mobj.group(1)

        template = templater.parsestring(self.templates[kw], quoted=False)

        self.t.use_template(template)

        self.ui.pushbuffer()

        self.t.show(changenode=node, root=self.repo.root, file=path)

        kwsub = templater.firstline(self.ui.popbuffer())

        return '$%s: %s $' % (kw, kwsub)

def reposetup(ui, repo):

    '''Sets up repo, and filelog especially, as kwrepo and kwfilelog

    for keyword substitution. This is done for local repos only.'''

    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):

        '''

        Superclass over filelog to customize it's read, add, cmp methods.

        Keywords are "stored" unexpanded, and expanded on reading.

        '''

        def __init__(self, opener, path, repo,

                     defversion=revlog.REVLOG_DEFAULT_VERSION):

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

            self._repo = repo

            self._path = path

            # only init kwtemplater if needed

                self.kwt = kwtemplater(ui, repo)

            else:

                self.kwt = None

        def iskwcandidate(self, data):

            '''Decides whether to act on keywords.'''

            return self.kwt is not None and not util.binary(data)

        def read(self, node):

            '''Substitutes keywords when reading filelog.'''

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

            if self.iskwcandidate(data):

                c = context.filectx(self._repo, self._path,

                                    fileid=node, filelog=self)

                return self.kwt.re_kw.sub(lambda m:

                        self.kwt.expand(m, self._path, c.node()), data)

            return data

        def add(self, text, meta, tr, link, p1=None, p2=None):

            '''Removes keyword substitutions when adding to filelog.'''

            if self.iskwcandidate(text):

                text = self.kwt.re_kw.sub(r'$\1$', text)

            return super(kwfilelog, self).add(text,

                            meta, tr, link, p1=p1, p2=p2)

        def cmp(self, node, text):

            '''Removes keyword substitutions for comparison.'''

            if self.iskwcandidate(text):

                text = self.kwt.re_kw.sub(r'$\1$', text)

            return super(kwfilelog, self).cmp(node, text)

    filelog.filelog = kwfilelog

    repo.__class__ = kwrepo

    # configure pretxncommit hook

    ui.setconfig('hooks', 'pretxncommit.keyword',

            'python:%s.pretxnkw' % getmodulename())

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

    '''pretxncommit hook that collects candidates for keyword expansion

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

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

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

        return

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

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

    if not candidates:

        return

    kwt = kwtemplater(ui, repo)

    node = bin(args['node'])

    for f in candidates:

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

        if not util.binary(data):

            data, kwct = kwt.re_kw.subn(lambda m: kwt.expand(m, f, node), data)

            if kwct:

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

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