# 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.
#
# Expansions spanning more than one line are truncated to their first line.
# Incremental expansion (like CVS' $Log$) is not supported.
#
# Setup in hgrc:
#
#     # enable extension
#     keyword = /full/path/to/keyword.py
#     # or, if script in hgext folder:
#     # hgext.keyword =

'''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.

Example:
     # 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}
     ...

If you do not have any [keywordmaps] configured the extension falls back on
the following defaults:

     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
'''

try:
    from mercurial.demandload import * # stable
    from mercurial.i18n import gettext as _
    demandload(globals(), 'mercurial:cmdutil,templater,util')
    demandload(globals(), 'mercurial:context,filelog,revlog')
    demandload(globals(), 're time')
except ImportError:                    # demandimport
    from mercurial.i18n import _
    from mercurial import cmdutil, templater, util
    from mercurial import context, filelog, revlog
    import re, 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]))

class kwtemplater(object):
    '''
    Sets up keyword templates, corresponding keyword regex, and
    provides keyword substitution functions.
    '''
    def __init__(self, ui, repo):
        self.ui = ui
        self.repo = repo
        templates = dict(ui.configitems('keywordmaps'))
        if templates:
            # parse templates here for less overhead in kwsub matchfunc
            for k in templates.keys():
                templates[k] = templater.parsestring(templates[k],
                        quoted=False)
        self.templates = templates or deftemplates
        self.re_kw = re.compile(r'\$(%s)[^$]*?\$' %
                '|'.join(re.escape(k) for k in self.templates.keys()))
        templater.common_filters['utcdate'] = utcdate
        try:
            self.t = cmdutil.changeset_templater(ui, repo,
                    False, '', False)
        except TypeError:
            # depending on hg rev changeset_templater has extra "brinfo" arg
            self.t = cmdutil.changeset_templater(ui, repo,
                    False, None, '', False)

    def kwsub(self, mobj, path, node):
        '''Substitutes keyword using corresponding template.'''
        kw = mobj.group(1)
        self.t.use_template(self.templates[kw])
        self.ui.pushbuffer()
        self.t.show(changenode=node, root=self.repo.root, file=path)
        keywordsub = templater.firstline(self.ui.popbuffer())
        return '$%s: %s $' % (kw, keywordsub)

    def expand(self, path, node, filelog, data):
        '''Returns data with expanded keywords.'''
        if util.binary(data):
            return data
        c = context.filectx(self.repo, path, fileid=node, filelog=filelog)
        cnode = c.node()
        return self.re_kw.sub(lambda m: self.kwsub(m, path, cnode), data)

    def shrink(self, text):
        '''Returns text with all keyword substitutions removed.'''
        if util.binary(text):
            return text
        return self.re_kw.sub(r'$\1$', text)

    def overwrite(self, candidates, node):
        '''Overwrites candidates in working dir expanding keywords.'''
        files = []
        for f in candidates:
            data = self.repo.wfile(f).read()
            if not util.binary(data):
                data, kwct = self.re_kw.subn(lambda m:
                        self.kwsub(m, f, node), data)
                if kwct:
                    self.ui.debug(_('overwriting %s expanding keywords\n') % f)
                    self.repo.wfile(f, 'w').write(data)
                    files.append(f)
        if files:
            self.repo.dirstate.update(files, 'n')

class kwfilelog(filelog.filelog):
    '''
    Superclass over filelog to customize its read, add, cmp methods.
    Keywords are "stored" unexpanded, and expanded on reading.
    '''
    def __init__(self, opener, path, kwtemplater,
                 defversion=revlog.REVLOG_DEFAULT_VERSION):
        super(kwfilelog, self).__init__(opener, path, defversion)
        self.path = path
        self.kwtemplater = kwtemplater

    def read(self, node):
        '''Substitutes keywords when reading filelog.'''
        data = super(kwfilelog, self).read(node)
        return self.kwtemplater.expand(self.path, node, self, data)

    def add(self, text, meta, tr, link, p1=None, p2=None):
        '''Removes keyword substitutions when adding to filelog.'''
        text = self.kwtemplater.shrink(text)
        return super(kwfilelog, self).add(text,
                        meta, tr, link, p1=p1, p2=p2)

    def cmp(self, node, text):
        '''Removes keyword substitutions for comparison.'''
        text = self.kwtemplater.shrink(text)
        return super(kwfilelog, self).cmp(node, text)


def reposetup(ui, repo):
    '''Sets up repo as kwrepo for keyword substitution.
    Overrides file method to return kwfilelog instead of filelog
    if file matches user configuration.
    Wraps commit to overwrite configured files with updated
    keyword substitutions.
    This is done for local repos only, and only if there are
    files configured at all for keyword substitution.'''

    if not repo.local():
        return

    inc, exc = [], ['.hg*']
    for pat, opt in repo.ui.configitems('keyword'):
        if opt != 'ignore':
            inc.append(pat)
        else:
            exc.append(pat)
    if not inc:
        return

    repo.kwfmatcher = util.matcher(repo.root, inc=inc, exc=exc)[1]

    class kwrepo(repo.__class__):
        def file(self, f):
            if f[0] == '/':
                f = f[1:]
            # only use kwfilelog when needed
            if self.kwfmatcher(f):
                kwt = kwtemplater(self.ui, self)
                return kwfilelog(self.sopener, f, kwt, self.revlogversion)
            else:
                return filelog.filelog(self.sopener, f, self.revlogversion)

        def commit(self, files=None, text="", user=None, date=None,
                match=util.always, force=False, lock=None, wlock=None,
                force_editor=False, p1=None, p2=None, extra={}):
            '''Wraps commit, expanding keywords of committed and
            configured files in working directory.'''
            wrelease = False
            if not wlock:
                wlock = self.wlock()
                wrelease = True
            try:
                removed = self.status()[2]

                node = super(kwrepo, self).commit(files=files,
                        text=text, user=user, date=date,
                        match=match, force=force, lock=lock, wlock=wlock,
                        force_editor=force_editor, p1=p1, p2=p2, extra=extra)
                if node is None:
                    return node

                candidates = self.changelog.read(node)[3]
                candidates = [f for f in candidates if f not in removed
                        and not self._link(f) and self.kwfmatcher(f)]
                if not candidates:
                    return node

                kwt = kwtemplater(self.ui, self)
                kwt.overwrite(candidates, node)
                return node
            finally:
                if wrelease:
                    wlock.release()

    repo.__class__ = kwrepo