mercurial/subrepo.py

# subrepo.py - sub-repository handling for Mercurial
#
# Copyright 2009-2010 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

import errno, os, re, xml.dom.minidom, shutil, posixpath, sys
import stat, subprocess, tarfile
from i18n import _
import config, scmutil, util, node, error, cmdutil, bookmarks, match as matchmod
hg = None
propertycache = util.propertycache

nullstate = ('', '', 'empty')

def _expandedabspath(path):
    '''
    get a path or url and if it is a path expand it and return an absolute path
    '''
    expandedpath = util.urllocalpath(util.expandpath(path))
    u = util.url(expandedpath)
    if not u.scheme:
        path = util.normpath(os.path.abspath(u.path))
    return path

def _getstorehashcachename(remotepath):
    '''get a unique filename for the store hash cache of a remote repository'''
    return util.sha1(_expandedabspath(remotepath)).hexdigest()[0:12]

def _calcfilehash(filename):
    data = ''
    if os.path.exists(filename):
        fd = open(filename, 'rb')
        data = fd.read()
        fd.close()
    return util.sha1(data).hexdigest()

class SubrepoAbort(error.Abort):
    """Exception class used to avoid handling a subrepo error more than once"""
    def __init__(self, *args, **kw):
        error.Abort.__init__(self, *args, **kw)
        self.subrepo = kw.get('subrepo')
        self.cause = kw.get('cause')

def annotatesubrepoerror(func):
    def decoratedmethod(self, *args, **kargs):
        try:
            res = func(self, *args, **kargs)
        except SubrepoAbort, ex:
            # This exception has already been handled
            raise ex
        except error.Abort, ex:
            subrepo = subrelpath(self)
            errormsg = str(ex) + ' ' + _('(in subrepo %s)') % subrepo
            # avoid handling this exception by raising a SubrepoAbort exception
            raise SubrepoAbort(errormsg, hint=ex.hint, subrepo=subrepo,
                               cause=sys.exc_info())
        return res
    return decoratedmethod

def state(ctx, ui):
    """return a state dict, mapping subrepo paths configured in .hgsub
    to tuple: (source from .hgsub, revision from .hgsubstate, kind
    (key in types dict))
    """
    p = config.config()
    def read(f, sections=None, remap=None):
        if f in ctx:
            try:
                data = ctx[f].data()
            except IOError, err:
                if err.errno != errno.ENOENT:
                    raise
                # handle missing subrepo spec files as removed
                ui.warn(_("warning: subrepo spec file %s not found\n") % f)
                return
            p.parse(f, data, sections, remap, read)
        else:
            raise util.Abort(_("subrepo spec file %s not found") % f)

    if '.hgsub' in ctx:
        read('.hgsub')

    for path, src in ui.configitems('subpaths'):
        p.set('subpaths', path, src, ui.configsource('subpaths', path))

    rev = {}
    if '.hgsubstate' in ctx:
        try:
            for i, l in enumerate(ctx['.hgsubstate'].data().splitlines()):
                l = l.lstrip()
                if not l:
                    continue
                try:
                    revision, path = l.split(" ", 1)
                except ValueError:
                    raise util.Abort(_("invalid subrepository revision "
                                       "specifier in .hgsubstate line %d")
                                     % (i + 1))
                rev[path] = revision
        except IOError, err:
            if err.errno != errno.ENOENT:
                raise

    def remap(src):
        for pattern, repl in p.items('subpaths'):
            # Turn r'C:\foo\bar' into r'C:\\foo\\bar' since re.sub
            # does a string decode.
            repl = repl.encode('string-escape')
            # However, we still want to allow back references to go
            # through unharmed, so we turn r'\\1' into r'\1'. Again,
            # extra escapes are needed because re.sub string decodes.
            repl = re.sub(r'\\\\([0-9]+)', r'\\\1', repl)
            try:
                src = re.sub(pattern, repl, src, 1)
            except re.error, e:
                raise util.Abort(_("bad subrepository pattern in %s: %s")
                                 % (p.source('subpaths', pattern), e))
        return src

    state = {}
    for path, src in p[''].items():
        kind = 'hg'
        if src.startswith('['):
            if ']' not in src:
                raise util.Abort(_('missing ] in subrepo source'))
            kind, src = src.split(']', 1)
            kind = kind[1:]
            src = src.lstrip() # strip any extra whitespace after ']'

        if not util.url(src).isabs():
            parent = _abssource(ctx._repo, abort=False)
            if parent:
                parent = util.url(parent)
                parent.path = posixpath.join(parent.path or '', src)
                parent.path = posixpath.normpath(parent.path)
                joined = str(parent)
                # Remap the full joined path and use it if it changes,
                # else remap the original source.
                remapped = remap(joined)
                if remapped == joined:
                    src = remap(src)
                else:
                    src = remapped

        src = remap(src)
        state[util.pconvert(path)] = (src.strip(), rev.get(path, ''), kind)

    return state

def writestate(repo, state):
    """rewrite .hgsubstate in (outer) repo with these subrepo states"""
    lines = ['%s %s\n' % (state[s][1], s) for s in sorted(state)]
    repo.wwrite('.hgsubstate', ''.join(lines), '')

def submerge(repo, wctx, mctx, actx, overwrite):
    """delegated from merge.applyupdates: merging of .hgsubstate file
    in working context, merging context and ancestor context"""
    if mctx == actx: # backwards?
        actx = wctx.p1()
    s1 = wctx.substate
    s2 = mctx.substate
    sa = actx.substate
    sm = {}

    repo.ui.debug("subrepo merge %s %s %s\n" % (wctx, mctx, actx))

    def debug(s, msg, r=""):
        if r:
            r = "%s:%s:%s" % r
        repo.ui.debug("  subrepo %s: %s %s\n" % (s, msg, r))

    for s, l in sorted(s1.iteritems()):
        a = sa.get(s, nullstate)
        ld = l # local state with possible dirty flag for compares
        if wctx.sub(s).dirty():
            ld = (l[0], l[1] + "+")
        if wctx == actx: # overwrite
            a = ld

        if s in s2:
            r = s2[s]
            if ld == r or r == a: # no change or local is newer
                sm[s] = l
                continue
            elif ld == a: # other side changed
                debug(s, "other changed, get", r)
                wctx.sub(s).get(r, overwrite)
                sm[s] = r
            elif ld[0] != r[0]: # sources differ
                if repo.ui.promptchoice(
                    _(' subrepository sources for %s differ\n'
                      'use (l)ocal source (%s) or (r)emote source (%s)?'
                      '$$ &Local $$ &Remote') % (s, l[0], r[0]), 0):
                    debug(s, "prompt changed, get", r)
                    wctx.sub(s).get(r, overwrite)
                    sm[s] = r
            elif ld[1] == a[1]: # local side is unchanged
                debug(s, "other side changed, get", r)
                wctx.sub(s).get(r, overwrite)
                sm[s] = r
            else:
                debug(s, "both sides changed, merge with", r)
                wctx.sub(s).merge(r)
                sm[s] = l
        elif ld == a: # remote removed, local unchanged
            debug(s, "remote removed, remove")
            wctx.sub(s).remove()
        elif a == nullstate: # not present in remote or ancestor
            debug(s, "local added, keep")
            sm[s] = l
            continue
        else:
            if repo.ui.promptchoice(
                _(' local changed subrepository %s which remote removed\n'
                  'use (c)hanged version or (d)elete?'
                  '$$ &Changed $$ &Delete') % s, 0):
                debug(s, "prompt remove")
                wctx.sub(s).remove()

    for s, r in sorted(s2.items()):
        if s in s1:
            continue
        elif s not in sa:
            debug(s, "remote added, get", r)
            mctx.sub(s).get(r)
            sm[s] = r
        elif r != sa[s]:
            if repo.ui.promptchoice(
                _(' remote changed subrepository %s which local removed\n'
                  'use (c)hanged version or (d)elete?'
                  '$$ &Changed $$ &Delete') % s, 0) == 0:
                debug(s, "prompt recreate", r)
                wctx.sub(s).get(r)
                sm[s] = r

    # record merged .hgsubstate
    writestate(repo, sm)

def _updateprompt(ui, sub, dirty, local, remote):
    if dirty:
        msg = (_(' subrepository sources for %s differ\n'
                 'use (l)ocal source (%s) or (r)emote source (%s)?\n'
                 '$$ &Local $$ &Remote')
               % (subrelpath(sub), local, remote))
    else:
        msg = (_(' subrepository sources for %s differ (in checked out '
                 'version)\n'
                 'use (l)ocal source (%s) or (r)emote source (%s)?\n'
                 '$$ &Local $$ &Remote')
               % (subrelpath(sub), local, remote))
    return ui.promptchoice(msg, 0)

def reporelpath(repo):
    """return path to this (sub)repo as seen from outermost repo"""
    parent = repo
    while util.safehasattr(parent, '_subparent'):
        parent = parent._subparent
    p = parent.root.rstrip(os.sep)
    return repo.root[len(p) + 1:]

def subrelpath(sub):
    """return path to this subrepo as seen from outermost repo"""
    if util.safehasattr(sub, '_relpath'):
        return sub._relpath
    if not util.safehasattr(sub, '_repo'):
        return sub._path
    return reporelpath(sub._repo)

def _abssource(repo, push=False, abort=True):
    """return pull/push path of repo - either based on parent repo .hgsub info
    or on the top repo config. Abort or return None if no source found."""
    if util.safehasattr(repo, '_subparent'):
        source = util.url(repo._subsource)
        if source.isabs():
            return str(source)
        source.path = posixpath.normpath(source.path)
        parent = _abssource(repo._subparent, push, abort=False)
        if parent:
            parent = util.url(util.pconvert(parent))
            parent.path = posixpath.join(parent.path or '', source.path)
            parent.path = posixpath.normpath(parent.path)
            return str(parent)
    else: # recursion reached top repo
        if util.safehasattr(repo, '_subtoppath'):
            return repo._subtoppath
        if push and repo.ui.config('paths', 'default-push'):
            return repo.ui.config('paths', 'default-push')
        if repo.ui.config('paths', 'default'):
            return repo.ui.config('paths', 'default')
        if repo.sharedpath != repo.path:
            # chop off the .hg component to get the default path form
            return os.path.dirname(repo.sharedpath)
    if abort:
        raise util.Abort(_("default path for subrepository not found"))

def itersubrepos(ctx1, ctx2):
    """find subrepos in ctx1 or ctx2"""
    # Create a (subpath, ctx) mapping where we prefer subpaths from
    # ctx1. The subpaths from ctx2 are important when the .hgsub file
    # has been modified (in ctx2) but not yet committed (in ctx1).
    subpaths = dict.fromkeys(ctx2.substate, ctx2)
    subpaths.update(dict.fromkeys(ctx1.substate, ctx1))
    for subpath, ctx in sorted(subpaths.iteritems()):
        yield subpath, ctx.sub(subpath)

def subrepo(ctx, path):
    """return instance of the right subrepo class for subrepo in path"""
    # subrepo inherently violates our import layering rules
    # because it wants to make repo objects from deep inside the stack
    # so we manually delay the circular imports to not break
    # scripts that don't use our demand-loading
    global hg
    import hg as h
    hg = h

    scmutil.pathauditor(ctx._repo.root)(path)
    state = ctx.substate[path]
    if state[2] not in types:
        raise util.Abort(_('unknown subrepo type %s') % state[2])
    return types[state[2]](ctx, path, state[:2])

# subrepo classes need to implement the following abstract class:

class abstractsubrepo(object):

    def storeclean(self, path):
        """
        returns true if the repository has not changed since it was last
        cloned from or pushed to a given repository.
        """
        return False

    def dirty(self, ignoreupdate=False):
        """returns true if the dirstate of the subrepo is dirty or does not
        match current stored state. If ignoreupdate is true, only check
        whether the subrepo has uncommitted changes in its dirstate.
        """
        raise NotImplementedError

    def basestate(self):
        """current working directory base state, disregarding .hgsubstate
        state and working directory modifications"""
        raise NotImplementedError

    def checknested(self, path):
        """check if path is a subrepository within this repository"""
        return False

    def commit(self, text, user, date):
        """commit the current changes to the subrepo with the given
        log message. Use given user and date if possible. Return the
        new state of the subrepo.
        """
        raise NotImplementedError

    def remove(self):
        """remove the subrepo

        (should verify the dirstate is not dirty first)
        """
        raise NotImplementedError

    def get(self, state, overwrite=False):
        """run whatever commands are needed to put the subrepo into
        this state
        """
        raise NotImplementedError

    def merge(self, state):
        """merge currently-saved state with the new state."""
        raise NotImplementedError

    def push(self, opts):
        """perform whatever action is analogous to 'hg push'

        This may be a no-op on some systems.
        """
        raise NotImplementedError

    def add(self, ui, match, dryrun, listsubrepos, prefix, explicitonly):
        return []

    def status(self, rev2, **opts):
        return [], [], [], [], [], [], []

    def diff(self, ui, diffopts, node2, match, prefix, **opts):
        pass

    def outgoing(self, ui, dest, opts):
        return 1

    def incoming(self, ui, source, opts):
        return 1

    def files(self):
        """return filename iterator"""
        raise NotImplementedError

    def filedata(self, name):
        """return file data"""
        raise NotImplementedError

    def fileflags(self, name):
        """return file flags"""
        return ''

    def archive(self, ui, archiver, prefix, match=None):
        if match is not None:
            files = [f for f in self.files() if match(f)]
        else:
            files = self.files()
        total = len(files)
        relpath = subrelpath(self)
        ui.progress(_('archiving (%s)') % relpath, 0,
                    unit=_('files'), total=total)
        for i, name in enumerate(files):
            flags = self.fileflags(name)
            mode = 'x' in flags and 0755 or 0644
            symlink = 'l' in flags
            archiver.addfile(os.path.join(prefix, self._path, name),
                             mode, symlink, self.filedata(name))
            ui.progress(_('archiving (%s)') % relpath, i + 1,
                        unit=_('files'), total=total)
        ui.progress(_('archiving (%s)') % relpath, None)
        return total

    def walk(self, match):
        '''
        walk recursively through the directory tree, finding all files
        matched by the match function
        '''
        pass

    def forget(self, ui, match, prefix):
        return ([], [])

    def revert(self, ui, substate, *pats, **opts):
        ui.warn('%s: reverting %s subrepos is unsupported\n' \
            % (substate[0], substate[2]))
        return []

class hgsubrepo(abstractsubrepo):
    def __init__(self, ctx, path, state):
        self._path = path
        self._state = state
        r = ctx._repo
        root = r.wjoin(path)
        create = False
        if not os.path.exists(os.path.join(root, '.hg')):
            create = True
            util.makedirs(root)
        self._repo = hg.repository(r.baseui, root, create=create)
        for s, k in [('ui', 'commitsubrepos')]:
            v = r.ui.config(s, k)
            if v:
                self._repo.ui.setconfig(s, k, v)
        self._repo.ui.setconfig('ui', '_usedassubrepo', 'True')
        self._initrepo(r, state[0], create)

    def storeclean(self, path):
        clean = True
        lock = self._repo.lock()
        itercache = self._calcstorehash(path)
        try:
            for filehash in self._readstorehashcache(path):
                if filehash != itercache.next():
                    clean = False
                    break
        except StopIteration:
            # the cached and current pull states have a different size
            clean = False
        if clean:
            try:
                itercache.next()
                # the cached and current pull states have a different size
                clean = False
            except StopIteration:
                pass
        lock.release()
        return clean

    def _calcstorehash(self, remotepath):
        '''calculate a unique "store hash"

        This method is used to to detect when there are changes that may
        require a push to a given remote path.'''
        # sort the files that will be hashed in increasing (likely) file size
        filelist = ('bookmarks', 'store/phaseroots', 'store/00changelog.i')
        yield '# %s\n' % _expandedabspath(remotepath)
        for relname in filelist:
            absname = os.path.normpath(self._repo.join(relname))
            yield '%s = %s\n' % (relname, _calcfilehash(absname))

    def _getstorehashcachepath(self, remotepath):
        '''get a unique path for the store hash cache'''
        return self._repo.join(os.path.join(
            'cache', 'storehash', _getstorehashcachename(remotepath)))

    def _readstorehashcache(self, remotepath):
        '''read the store hash cache for a given remote repository'''
        cachefile = self._getstorehashcachepath(remotepath)
        if not os.path.exists(cachefile):
            return ''
        fd = open(cachefile, 'r')
        pullstate = fd.readlines()
        fd.close()
        return pullstate

    def _cachestorehash(self, remotepath):
        '''cache the current store hash

        Each remote repo requires its own store hash cache, because a subrepo
        store may be "clean" versus a given remote repo, but not versus another
        '''
        cachefile = self._getstorehashcachepath(remotepath)
        lock = self._repo.lock()
        storehash = list(self._calcstorehash(remotepath))
        cachedir = os.path.dirname(cachefile)
        if not os.path.exists(cachedir):
            util.makedirs(cachedir, notindexed=True)
        fd = open(cachefile, 'w')
        fd.writelines(storehash)
        fd.close()
        lock.release()

    @annotatesubrepoerror
    def _initrepo(self, parentrepo, source, create):
        self._repo._subparent = parentrepo
        self._repo._subsource = source

        if create:
            fp = self._repo.opener("hgrc", "w", text=True)
            fp.write('[paths]\n')

            def addpathconfig(key, value):
                if value:
                    fp.write('%s = %s\n' % (key, value))
                    self._repo.ui.setconfig('paths', key, value)

            defpath = _abssource(self._repo, abort=False)
            defpushpath = _abssource(self._repo, True, abort=False)
            addpathconfig('default', defpath)
            if defpath != defpushpath:
                addpathconfig('default-push', defpushpath)
            fp.close()

    @annotatesubrepoerror
    def add(self, ui, match, dryrun, listsubrepos, prefix, explicitonly):
        return cmdutil.add(ui, self._repo, match, dryrun, listsubrepos,
                           os.path.join(prefix, self._path), explicitonly)

    @annotatesubrepoerror
    def status(self, rev2, **opts):
        try:
            rev1 = self._state[1]
            ctx1 = self._repo[rev1]
            ctx2 = self._repo[rev2]
            return self._repo.status(ctx1, ctx2, **opts)
        except error.RepoLookupError, inst:
            self._repo.ui.warn(_('warning: error "%s" in subrepository "%s"\n')
                               % (inst, subrelpath(self)))
            return [], [], [], [], [], [], []

    @annotatesubrepoerror
    def diff(self, ui, diffopts, node2, match, prefix, **opts):
        try:
            node1 = node.bin(self._state[1])
            # We currently expect node2 to come from substate and be
            # in hex format
            if node2 is not None:
                node2 = node.bin(node2)
            cmdutil.diffordiffstat(ui, self._repo, diffopts,
                                   node1, node2, match,
                                   prefix=posixpath.join(prefix, self._path),
                                   listsubrepos=True, **opts)
        except error.RepoLookupError, inst:
            self._repo.ui.warn(_('warning: error "%s" in subrepository "%s"\n')
                               % (inst, subrelpath(self)))

    @annotatesubrepoerror
    def archive(self, ui, archiver, prefix, match=None):
        self._get(self._state + ('hg',))
        total = abstractsubrepo.archive(self, ui, archiver, prefix, match)
        rev = self._state[1]
        ctx = self._repo[rev]
        for subpath in ctx.substate:
            s = subrepo(ctx, subpath)
            submatch = matchmod.narrowmatcher(subpath, match)
            total += s.archive(
                ui, archiver, os.path.join(prefix, self._path), submatch)
        return total

    @annotatesubrepoerror
    def dirty(self, ignoreupdate=False):
        r = self._state[1]
        if r == '' and not ignoreupdate: # no state recorded
            return True
        w = self._repo[None]
        if r != w.p1().hex() and not ignoreupdate:
            # different version checked out
            return True
        return w.dirty() # working directory changed

    def basestate(self):
        return self._repo['.'].hex()

    def checknested(self, path):
        return self._repo._checknested(self._repo.wjoin(path))

    @annotatesubrepoerror
    def commit(self, text, user, date):
        # don't bother committing in the subrepo if it's only been
        # updated
        if not self.dirty(True):
            return self._repo['.'].hex()
        self._repo.ui.debug("committing subrepo %s\n" % subrelpath(self))
        n = self._repo.commit(text, user, date)
        if not n:
            return self._repo['.'].hex() # different version checked out
        return node.hex(n)

    @annotatesubrepoerror
    def remove(self):
        # we can't fully delete the repository as it may contain
        # local-only history
        self._repo.ui.note(_('removing subrepo %s\n') % subrelpath(self))
        hg.clean(self._repo, node.nullid, False)

    def _get(self, state):
        source, revision, kind = state
        if revision not in self._repo:
            self._repo._subsource = source
            srcurl = _abssource(self._repo)
            other = hg.peer(self._repo, {}, srcurl)
            if len(self._repo) == 0:
                self._repo.ui.status(_('cloning subrepo %s from %s\n')
                                     % (subrelpath(self), srcurl))
                parentrepo = self._repo._subparent
                shutil.rmtree(self._repo.path)
                other, cloned = hg.clone(self._repo._subparent.baseui, {},
                                         other, self._repo.root,
                                         update=False)
                self._repo = cloned.local()
                self._initrepo(parentrepo, source, create=True)
                self._cachestorehash(srcurl)
            else:
                self._repo.ui.status(_('pulling subrepo %s from %s\n')
                                     % (subrelpath(self), srcurl))
                cleansub = self.storeclean(srcurl)
                remotebookmarks = other.listkeys('bookmarks')
                self._repo.pull(other)
                bookmarks.updatefromremote(self._repo.ui, self._repo,
                                           remotebookmarks, srcurl)
                if cleansub:
                    # keep the repo clean after pull
                    self._cachestorehash(srcurl)

    @annotatesubrepoerror
    def get(self, state, overwrite=False):
        self._get(state)
        source, revision, kind = state
        self._repo.ui.debug("getting subrepo %s\n" % self._path)
        hg.updaterepo(self._repo, revision, overwrite)

    @annotatesubrepoerror
    def merge(self, state):
        self._get(state)
        cur = self._repo['.']
        dst = self._repo[state[1]]
        anc = dst.ancestor(cur)

        def mergefunc():
            if anc == cur and dst.branch() == cur.branch():
                self._repo.ui.debug("updating subrepo %s\n" % subrelpath(self))
                hg.update(self._repo, state[1])
            elif anc == dst:
                self._repo.ui.debug("skipping subrepo %s\n" % subrelpath(self))
            else:
                self._repo.ui.debug("merging subrepo %s\n" % subrelpath(self))
                hg.merge(self._repo, state[1], remind=False)

        wctx = self._repo[None]
        if self.dirty():
            if anc != dst:
                if _updateprompt(self._repo.ui, self, wctx.dirty(), cur, dst):
                    mergefunc()
            else:
                mergefunc()
        else:
            mergefunc()

    @annotatesubrepoerror
    def push(self, opts):
        force = opts.get('force')
        newbranch = opts.get('new_branch')
        ssh = opts.get('ssh')

        # push subrepos depth-first for coherent ordering
        c = self._repo['']
        subs = c.substate # only repos that are committed
        for s in sorted(subs):
            if c.sub(s).push(opts) == 0:
                return False

        dsturl = _abssource(self._repo, True)
        if not force:
            if self.storeclean(dsturl):
                self._repo.ui.status(
                    _('no changes made to subrepo %s since last push to %s\n')
                    % (subrelpath(self), dsturl))
                return None
        self._repo.ui.status(_('pushing subrepo %s to %s\n') %
            (subrelpath(self), dsturl))
        other = hg.peer(self._repo, {'ssh': ssh}, dsturl)
        res = self._repo.push(other, force, newbranch=newbranch)

        # the repo is now clean
        self._cachestorehash(dsturl)
        return res

    @annotatesubrepoerror
    def outgoing(self, ui, dest, opts):
        return hg.outgoing(ui, self._repo, _abssource(self._repo, True), opts)

    @annotatesubrepoerror
    def incoming(self, ui, source, opts):
        return hg.incoming(ui, self._repo, _abssource(self._repo, False), opts)

    @annotatesubrepoerror
    def files(self):
        rev = self._state[1]
        ctx = self._repo[rev]
        return ctx.manifest()

    def filedata(self, name):
        rev = self._state[1]
        return self._repo[rev][name].data()

    def fileflags(self, name):
        rev = self._state[1]
        ctx = self._repo[rev]
        return ctx.flags(name)

    def walk(self, match):
        ctx = self._repo[None]
        return ctx.walk(match)

    @annotatesubrepoerror
    def forget(self, ui, match, prefix):
        return cmdutil.forget(ui, self._repo, match,
                              os.path.join(prefix, self._path), True)

    @annotatesubrepoerror
    def revert(self, ui, substate, *pats, **opts):
        # reverting a subrepo is a 2 step process:
        # 1. if the no_backup is not set, revert all modified
        #    files inside the subrepo
        # 2. update the subrepo to the revision specified in
        #    the corresponding substate dictionary
        ui.status(_('reverting subrepo %s\n') % substate[0])
        if not opts.get('no_backup'):
            # Revert all files on the subrepo, creating backups
            # Note that this will not recursively revert subrepos
            # We could do it if there was a set:subrepos() predicate
            opts = opts.copy()
            opts['date'] = None
            opts['rev'] = substate[1]

            pats = []
            if not opts.get('all'):
                pats = ['set:modified()']
            self.filerevert(ui, *pats, **opts)

        # Update the repo to the revision specified in the given substate
        self.get(substate, overwrite=True)

    def filerevert(self, ui, *pats, **opts):
        ctx = self._repo[opts['rev']]
        parents = self._repo.dirstate.parents()
        if opts.get('all'):
            pats = ['set:modified()']
        else:
            pats = []
        cmdutil.revert(ui, self._repo, ctx, parents, *pats, **opts)

class svnsubrepo(abstractsubrepo):
    def __init__(self, ctx, path, state):
        self._path = path
        self._state = state
        self._ctx = ctx
        self._ui = ctx._repo.ui
        self._exe = util.findexe('svn')
        if not self._exe:
            raise util.Abort(_("'svn' executable not found for subrepo '%s'")
                             % self._path)

    def _svncommand(self, commands, filename='', failok=False):
        cmd = [self._exe]
        extrakw = {}
        if not self._ui.interactive():
            # Making stdin be a pipe should prevent svn from behaving
            # interactively even if we can't pass --non-interactive.
            extrakw['stdin'] = subprocess.PIPE
            # Starting in svn 1.5 --non-interactive is a global flag
            # instead of being per-command, but we need to support 1.4 so
            # we have to be intelligent about what commands take
            # --non-interactive.
            if commands[0] in ('update', 'checkout', 'commit'):
                cmd.append('--non-interactive')
        cmd.extend(commands)
        if filename is not None:
            path = os.path.join(self._ctx._repo.origroot, self._path, filename)
            cmd.append(path)
        env = dict(os.environ)
        # Avoid localized output, preserve current locale for everything else.
        lc_all = env.get('LC_ALL')
        if lc_all:
            env['LANG'] = lc_all
            del env['LC_ALL']
        env['LC_MESSAGES'] = 'C'
        p = subprocess.Popen(cmd, bufsize=-1, close_fds=util.closefds,
                             stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                              universal_newlines=True, env=env, **extrakw)
        stdout, stderr = p.communicate()
        stderr = stderr.strip()
        if not failok:
            if p.returncode:
                raise util.Abort(stderr or 'exited with code %d' % p.returncode)
            if stderr:
                self._ui.warn(stderr + '\n')
        return stdout, stderr

    @propertycache
    def _svnversion(self):
        output, err = self._svncommand(['--version', '--quiet'], filename=None)
        m = re.search(r'^(\d+)\.(\d+)', output)
        if not m:
            raise util.Abort(_('cannot retrieve svn tool version'))
        return (int(m.group(1)), int(m.group(2)))

    def _wcrevs(self):
        # Get the working directory revision as well as the last
        # commit revision so we can compare the subrepo state with
        # both. We used to store the working directory one.
        output, err = self._svncommand(['info', '--xml'])
        doc = xml.dom.minidom.parseString(output)
        entries = doc.getElementsByTagName('entry')
        lastrev, rev = '0', '0'
        if entries:
            rev = str(entries[0].getAttribute('revision')) or '0'
            commits = entries[0].getElementsByTagName('commit')
            if commits:
                lastrev = str(commits[0].getAttribute('revision')) or '0'
        return (lastrev, rev)

    def _wcrev(self):
        return self._wcrevs()[0]

    def _wcchanged(self):
        """Return (changes, extchanges, missing) where changes is True
        if the working directory was changed, extchanges is
        True if any of these changes concern an external entry and missing
        is True if any change is a missing entry.
        """
        output, err = self._svncommand(['status', '--xml'])
        externals, changes, missing = [], [], []
        doc = xml.dom.minidom.parseString(output)
        for e in doc.getElementsByTagName('entry'):
            s = e.getElementsByTagName('wc-status')
            if not s:
                continue
            item = s[0].getAttribute('item')
            props = s[0].getAttribute('props')
            path = e.getAttribute('path')
            if item == 'external':
                externals.append(path)
            elif item == 'missing':
                missing.append(path)
            if (item not in ('', 'normal', 'unversioned', 'external')
                or props not in ('', 'none', 'normal')):
                changes.append(path)
        for path in changes:
            for ext in externals:
                if path == ext or path.startswith(ext + os.sep):
                    return True, True, bool(missing)
        return bool(changes), False, bool(missing)

    def dirty(self, ignoreupdate=False):
        if not self._wcchanged()[0]:
            if self._state[1] in self._wcrevs() or ignoreupdate:
                return False
        return True

    def basestate(self):
        lastrev, rev = self._wcrevs()
        if lastrev != rev:
            # Last committed rev is not the same than rev. We would
            # like to take lastrev but we do not know if the subrepo
            # URL exists at lastrev.  Test it and fallback to rev it
            # is not there.
            try:
                self._svncommand(['list', '%s@%s' % (self._state[0], lastrev)])
                return lastrev
            except error.Abort:
                pass
        return rev

    @annotatesubrepoerror
    def commit(self, text, user, date):
        # user and date are out of our hands since svn is centralized
        changed, extchanged, missing = self._wcchanged()
        if not changed:
            return self.basestate()
        if extchanged:
            # Do not try to commit externals
            raise util.Abort(_('cannot commit svn externals'))
        if missing:
            # svn can commit with missing entries but aborting like hg
            # seems a better approach.
            raise util.Abort(_('cannot commit missing svn entries'))
        commitinfo, err = self._svncommand(['commit', '-m', text])
        self._ui.status(commitinfo)
        newrev = re.search('Committed revision ([0-9]+).', commitinfo)
        if not newrev:
            if not commitinfo.strip():
                # Sometimes, our definition of "changed" differs from
                # svn one. For instance, svn ignores missing files
                # when committing. If there are only missing files, no
                # commit is made, no output and no error code.
                raise util.Abort(_('failed to commit svn changes'))
            raise util.Abort(commitinfo.splitlines()[-1])
        newrev = newrev.groups()[0]
        self._ui.status(self._svncommand(['update', '-r', newrev])[0])
        return newrev

    @annotatesubrepoerror
    def remove(self):
        if self.dirty():
            self._ui.warn(_('not removing repo %s because '
                            'it has changes.\n' % self._path))
            return
        self._ui.note(_('removing subrepo %s\n') % self._path)

        def onerror(function, path, excinfo):
            if function is not os.remove:
                raise
            # read-only files cannot be unlinked under Windows
            s = os.stat(path)
            if (s.st_mode & stat.S_IWRITE) != 0:
                raise
            os.chmod(path, stat.S_IMODE(s.st_mode) | stat.S_IWRITE)
            os.remove(path)

        path = self._ctx._repo.wjoin(self._path)
        shutil.rmtree(path, onerror=onerror)
        try:
            os.removedirs(os.path.dirname(path))
        except OSError:
            pass

    @annotatesubrepoerror
    def get(self, state, overwrite=False):
        if overwrite:
            self._svncommand(['revert', '--recursive'])
        args = ['checkout']
        if self._svnversion >= (1, 5):
            args.append('--force')
        # The revision must be specified at the end of the URL to properly
        # update to a directory which has since been deleted and recreated.
        args.append('%s@%s' % (state[0], state[1]))
        status, err = self._svncommand(args, failok=True)
        if not re.search('Checked out revision [0-9]+.', status):
            if ('is already a working copy for a different URL' in err
                and (self._wcchanged()[:2] == (False, False))):
                # obstructed but clean working copy, so just blow it away.
                self.remove()
                self.get(state, overwrite=False)
                return
            raise util.Abort((status or err).splitlines()[-1])
        self._ui.status(status)

    @annotatesubrepoerror
    def merge(self, state):
        old = self._state[1]
        new = state[1]
        wcrev = self._wcrev()
        if new != wcrev:
            dirty = old == wcrev or self._wcchanged()[0]
            if _updateprompt(self._ui, self, dirty, wcrev, new):
                self.get(state, False)

    def push(self, opts):
        # push is a no-op for SVN
        return True

    @annotatesubrepoerror
    def files(self):
        output = self._svncommand(['list', '--recursive', '--xml'])[0]
        doc = xml.dom.minidom.parseString(output)
        paths = []
        for e in doc.getElementsByTagName('entry'):
            kind = str(e.getAttribute('kind'))
            if kind != 'file':
                continue
            name = ''.join(c.data for c
                           in e.getElementsByTagName('name')[0].childNodes
                           if c.nodeType == c.TEXT_NODE)
            paths.append(name.encode('utf-8'))
        return paths

    def filedata(self, name):
        return self._svncommand(['cat'], name)[0]


class gitsubrepo(abstractsubrepo):
    def __init__(self, ctx, path, state):
        self._state = state
        self._ctx = ctx
        self._path = path
        self._relpath = os.path.join(reporelpath(ctx._repo), path)
        self._abspath = ctx._repo.wjoin(path)
        self._subparent = ctx._repo
        self._ui = ctx._repo.ui
        self._ensuregit()

    def _ensuregit(self):
        try:
            self._gitexecutable = 'git'
            out, err = self._gitnodir(['--version'])
        except OSError, e:
            if e.errno != 2 or os.name != 'nt':
                raise
            self._gitexecutable = 'git.cmd'
            out, err = self._gitnodir(['--version'])
        m = re.search(r'^git version (\d+)\.(\d+)\.(\d+)', out)
        if not m:
            self._ui.warn(_('cannot retrieve git version'))
            return
        version = (int(m.group(1)), m.group(2), m.group(3))
        # git 1.4.0 can't work at all, but 1.5.X can in at least some cases,
        # despite the docstring comment.  For now, error on 1.4.0, warn on
        # 1.5.0 but attempt to continue.
        if version < (1, 5, 0):
            raise util.Abort(_('git subrepo requires at least 1.6.0 or later'))
        elif version < (1, 6, 0):
            self._ui.warn(_('git subrepo requires at least 1.6.0 or later'))

    def _gitcommand(self, commands, env=None, stream=False):
        return self._gitdir(commands, env=env, stream=stream)[0]

    def _gitdir(self, commands, env=None, stream=False):
        return self._gitnodir(commands, env=env, stream=stream,
                              cwd=self._abspath)

    def _gitnodir(self, commands, env=None, stream=False, cwd=None):
        """Calls the git command

        The methods tries to call the git command. versions prior to 1.6.0
        are not supported and very probably fail.
        """
        self._ui.debug('%s: git %s\n' % (self._relpath, ' '.join(commands)))
        # unless ui.quiet is set, print git's stderr,
        # which is mostly progress and useful info
        errpipe = None
        if self._ui.quiet:
            errpipe = open(os.devnull, 'w')
        p = subprocess.Popen([self._gitexecutable] + commands, bufsize=-1,
                             cwd=cwd, env=env, close_fds=util.closefds,
                             stdout=subprocess.PIPE, stderr=errpipe)
        if stream:
            return p.stdout, None

        retdata = p.stdout.read().strip()
        # wait for the child to exit to avoid race condition.
        p.wait()

        if p.returncode != 0 and p.returncode != 1:
            # there are certain error codes that are ok
            command = commands[0]
            if command in ('cat-file', 'symbolic-ref'):
                return retdata, p.returncode
            # for all others, abort
            raise util.Abort('git %s error %d in %s' %
                             (command, p.returncode, self._relpath))

        return retdata, p.returncode

    def _gitmissing(self):
        return not os.path.exists(os.path.join(self._abspath, '.git'))

    def _gitstate(self):
        return self._gitcommand(['rev-parse', 'HEAD'])

    def _gitcurrentbranch(self):
        current, err = self._gitdir(['symbolic-ref', 'HEAD', '--quiet'])
        if err:
            current = None
        return current

    def _gitremote(self, remote):
        out = self._gitcommand(['remote', 'show', '-n', remote])
        line = out.split('\n')[1]
        i = line.index('URL: ') + len('URL: ')
        return line[i:]

    def _githavelocally(self, revision):
        out, code = self._gitdir(['cat-file', '-e', revision])
        return code == 0

    def _gitisancestor(self, r1, r2):
        base = self._gitcommand(['merge-base', r1, r2])
        return base == r1

    def _gitisbare(self):
        return self._gitcommand(['config', '--bool', 'core.bare']) == 'true'

    def _gitupdatestat(self):
        """This must be run before git diff-index.
        diff-index only looks at changes to file stat;
        this command looks at file contents and updates the stat."""
        self._gitcommand(['update-index', '-q', '--refresh'])

    def _gitbranchmap(self):
        '''returns 2 things:
        a map from git branch to revision
        a map from revision to branches'''
        branch2rev = {}
        rev2branch = {}

        out = self._gitcommand(['for-each-ref', '--format',
                                '%(objectname) %(refname)'])
        for line in out.split('\n'):
            revision, ref = line.split(' ')
            if (not ref.startswith('refs/heads/') and
                not ref.startswith('refs/remotes/')):
                continue
            if ref.startswith('refs/remotes/') and ref.endswith('/HEAD'):
                continue # ignore remote/HEAD redirects
            branch2rev[ref] = revision
            rev2branch.setdefault(revision, []).append(ref)
        return branch2rev, rev2branch

    def _gittracking(self, branches):
        'return map of remote branch to local tracking branch'
        # assumes no more than one local tracking branch for each remote
        tracking = {}
        for b in branches:
            if b.startswith('refs/remotes/'):
                continue
            bname = b.split('/', 2)[2]
            remote = self._gitcommand(['config', 'branch.%s.remote' % bname])
            if remote:
                ref = self._gitcommand(['config', 'branch.%s.merge' % bname])
                tracking['refs/remotes/%s/%s' %
                         (remote, ref.split('/', 2)[2])] = b
        return tracking

    def _abssource(self, source):
        if '://' not in source:
            # recognize the scp syntax as an absolute source
            colon = source.find(':')
            if colon != -1 and '/' not in source[:colon]:
                return source
        self._subsource = source
        return _abssource(self)

    def _fetch(self, source, revision):
        if self._gitmissing():
            source = self._abssource(source)
            self._ui.status(_('cloning subrepo %s from %s\n') %
                            (self._relpath, source))
            self._gitnodir(['clone', source, self._abspath])
        if self._githavelocally(revision):
            return
        self._ui.status(_('pulling subrepo %s from %s\n') %
                        (self._relpath, self._gitremote('origin')))
        # try only origin: the originally cloned repo
        self._gitcommand(['fetch'])
        if not self._githavelocally(revision):
            raise util.Abort(_("revision %s does not exist in subrepo %s\n") %
                               (revision, self._relpath))

    @annotatesubrepoerror
    def dirty(self, ignoreupdate=False):
        if self._gitmissing():
            return self._state[1] != ''
        if self._gitisbare():
            return True
        if not ignoreupdate and self._state[1] != self._gitstate():
            # different version checked out
            return True
        # check for staged changes or modified files; ignore untracked files
        self._gitupdatestat()
        out, code = self._gitdir(['diff-index', '--quiet', 'HEAD'])
        return code == 1

    def basestate(self):
        return self._gitstate()

    @annotatesubrepoerror
    def get(self, state, overwrite=False):
        source, revision, kind = state
        if not revision:
            self.remove()
            return
        self._fetch(source, revision)
        # if the repo was set to be bare, unbare it
        if self._gitisbare():
            self._gitcommand(['config', 'core.bare', 'false'])
            if self._gitstate() == revision:
                self._gitcommand(['reset', '--hard', 'HEAD'])
                return
        elif self._gitstate() == revision:
            if overwrite:
                # first reset the index to unmark new files for commit, because
                # reset --hard will otherwise throw away files added for commit,
                # not just unmark them.
                self._gitcommand(['reset', 'HEAD'])
                self._gitcommand(['reset', '--hard', 'HEAD'])
            return
        branch2rev, rev2branch = self._gitbranchmap()

        def checkout(args):
            cmd = ['checkout']
            if overwrite:
                # first reset the index to unmark new files for commit, because
                # the -f option will otherwise throw away files added for
                # commit, not just unmark them.
                self._gitcommand(['reset', 'HEAD'])
                cmd.append('-f')
            self._gitcommand(cmd + args)

        def rawcheckout():
            # no branch to checkout, check it out with no branch
            self._ui.warn(_('checking out detached HEAD in subrepo %s\n') %
                          self._relpath)
            self._ui.warn(_('check out a git branch if you intend '
                            'to make changes\n'))
            checkout(['-q', revision])

        if revision not in rev2branch:
            rawcheckout()
            return
        branches = rev2branch[revision]
        firstlocalbranch = None
        for b in branches:
            if b == 'refs/heads/master':
                # master trumps all other branches
                checkout(['refs/heads/master'])
                return
            if not firstlocalbranch and not b.startswith('refs/remotes/'):
                firstlocalbranch = b
        if firstlocalbranch:
            checkout([firstlocalbranch])
            return

        tracking = self._gittracking(branch2rev.keys())
        # choose a remote branch already tracked if possible
        remote = branches[0]
        if remote not in tracking:
            for b in branches:
                if b in tracking:
                    remote = b
                    break

        if remote not in tracking:
            # create a new local tracking branch
            local = remote.split('/', 3)[3]
            checkout(['-b', local, remote])
        elif self._gitisancestor(branch2rev[tracking[remote]], remote):
            # When updating to a tracked remote branch,
            # if the local tracking branch is downstream of it,
            # a normal `git pull` would have performed a "fast-forward merge"
            # which is equivalent to updating the local branch to the remote.
            # Since we are only looking at branching at update, we need to
            # detect this situation and perform this action lazily.
            if tracking[remote] != self._gitcurrentbranch():
                checkout([tracking[remote]])
            self._gitcommand(['merge', '--ff', remote])
        else:
            # a real merge would be required, just checkout the revision
            rawcheckout()

    @annotatesubrepoerror
    def commit(self, text, user, date):
        if self._gitmissing():
            raise util.Abort(_("subrepo %s is missing") % self._relpath)
        cmd = ['commit', '-a', '-m', text]
        env = os.environ.copy()
        if user:
            cmd += ['--author', user]
        if date:
            # git's date parser silently ignores when seconds < 1e9
            # convert to ISO8601
            env['GIT_AUTHOR_DATE'] = util.datestr(date,
                                                  '%Y-%m-%dT%H:%M:%S %1%2')
        self._gitcommand(cmd, env=env)
        # make sure commit works otherwise HEAD might not exist under certain
        # circumstances
        return self._gitstate()

    @annotatesubrepoerror
    def merge(self, state):
        source, revision, kind = state
        self._fetch(source, revision)
        base = self._gitcommand(['merge-base', revision, self._state[1]])
        self._gitupdatestat()
        out, code = self._gitdir(['diff-index', '--quiet', 'HEAD'])

        def mergefunc():
            if base == revision:
                self.get(state) # fast forward merge
            elif base != self._state[1]:
                self._gitcommand(['merge', '--no-commit', revision])

        if self.dirty():
            if self._gitstate() != revision:
                dirty = self._gitstate() == self._state[1] or code != 0
                if _updateprompt(self._ui, self, dirty,
                                 self._state[1][:7], revision[:7]):
                    mergefunc()
        else:
            mergefunc()

    @annotatesubrepoerror
    def push(self, opts):
        force = opts.get('force')

        if not self._state[1]:
            return True
        if self._gitmissing():
            raise util.Abort(_("subrepo %s is missing") % self._relpath)
        # if a branch in origin contains the revision, nothing to do
        branch2rev, rev2branch = self._gitbranchmap()
        if self._state[1] in rev2branch:
            for b in rev2branch[self._state[1]]:
                if b.startswith('refs/remotes/origin/'):
                    return True
        for b, revision in branch2rev.iteritems():
            if b.startswith('refs/remotes/origin/'):
                if self._gitisancestor(self._state[1], revision):
                    return True
        # otherwise, try to push the currently checked out branch
        cmd = ['push']
        if force:
            cmd.append('--force')

        current = self._gitcurrentbranch()
        if current:
            # determine if the current branch is even useful
            if not self._gitisancestor(self._state[1], current):
                self._ui.warn(_('unrelated git branch checked out '
                                'in subrepo %s\n') % self._relpath)
                return False
            self._ui.status(_('pushing branch %s of subrepo %s\n') %
                            (current.split('/', 2)[2], self._relpath))
            self._gitcommand(cmd + ['origin', current])
            return True
        else:
            self._ui.warn(_('no branch checked out in subrepo %s\n'
                            'cannot push revision %s\n') %
                          (self._relpath, self._state[1]))
            return False

    @annotatesubrepoerror
    def remove(self):
        if self._gitmissing():
            return
        if self.dirty():
            self._ui.warn(_('not removing repo %s because '
                            'it has changes.\n') % self._relpath)
            return
        # we can't fully delete the repository as it may contain
        # local-only history
        self._ui.note(_('removing subrepo %s\n') % self._relpath)
        self._gitcommand(['config', 'core.bare', 'true'])
        for f in os.listdir(self._abspath):
            if f == '.git':
                continue
            path = os.path.join(self._abspath, f)
            if os.path.isdir(path) and not os.path.islink(path):
                shutil.rmtree(path)
            else:
                os.remove(path)

    def archive(self, ui, archiver, prefix, match=None):
        total = 0
        source, revision = self._state
        if not revision:
            return total
        self._fetch(source, revision)

        # Parse git's native archive command.
        # This should be much faster than manually traversing the trees
        # and objects with many subprocess calls.
        tarstream = self._gitcommand(['archive', revision], stream=True)
        tar = tarfile.open(fileobj=tarstream, mode='r|')
        relpath = subrelpath(self)
        ui.progress(_('archiving (%s)') % relpath, 0, unit=_('files'))
        for i, info in enumerate(tar):
            if info.isdir():
                continue
            if match and not match(info.name):
                continue
            if info.issym():
                data = info.linkname
            else:
                data = tar.extractfile(info).read()
            archiver.addfile(os.path.join(prefix, self._path, info.name),
                             info.mode, info.issym(), data)
            total += 1
            ui.progress(_('archiving (%s)') % relpath, i + 1,
                        unit=_('files'))
        ui.progress(_('archiving (%s)') % relpath, None)
        return total


    @annotatesubrepoerror
    def status(self, rev2, **opts):
        rev1 = self._state[1]
        if self._gitmissing() or not rev1:
            # if the repo is missing, return no results
            return [], [], [], [], [], [], []
        modified, added, removed = [], [], []
        self._gitupdatestat()
        if rev2:
            command = ['diff-tree', rev1, rev2]
        else:
            command = ['diff-index', rev1]
        out = self._gitcommand(command)
        for line in out.split('\n'):
            tab = line.find('\t')
            if tab == -1:
                continue
            status, f = line[tab - 1], line[tab + 1:]
            if status == 'M':
                modified.append(f)
            elif status == 'A':
                added.append(f)
            elif status == 'D':
                removed.append(f)

        deleted = unknown = ignored = clean = []
        return modified, added, removed, deleted, unknown, ignored, clean

types = {
    'hg': hgsubrepo,
    'svn': svnsubrepo,
    'git': gitsubrepo,
    }