# keyword.py - keyword expansion for mercurial

# $Id$

'''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.

For in-depth discussion refer to

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

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.

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

The extension provides an additional UTC-date filter.

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}

    ...

'''

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]

def kwfmatches(ui, repo, files):

    '''Selects candidates for keyword substitution

    configured in keyword section in hgrc.'''

    inc, exc = [], []

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

        if opt != 'ignore':

            inc.append(pat)

        else:

            exc.append(pat)

    if not inc:

        return []

    kwfmatcher = util.matcher(repo.root, inc=inc, exc=['.hg*']+exc)[1]

    return [f for f in files if kwfmatcher(f)]

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 with 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

            if not isinstance(repo, int) and kwfmatches(ui, repo, [path]):

                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]

    candidates = kwfmatches(ui, repo, modified+added)

    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)