# unionrepo.py - repository class for viewing union of repositories

#

# Derived from Mercurial 2.5 bundlerepo.py

# Copyright 2006, 2007 Benoit Boissinot <bboissin@gmail.com>

# Copyright 2013 Unity Technologies, Mads Kiilerich <madski@unity3d.com>

#

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

# GNU General Public License version 2 or any later version.

"""Repository class for in-memory pull of one local repository to another.

"""

from mercurial.node import nullid

from mercurial import util, mdiff

from mercurial import localrepo, changelog, manifest, filelog, revlog

class unionrevlog(revlog.revlog):

    def __init__(self, opener, indexfile, revlog2, linkmapper):

        # How it works:

        # To retrieve a revision, we just need to know the node id so we can

        # look it up in revlog2.

        #

        # basemap is indexed with revisions coming from the second revlog.

        #

        # To differentiate a rev in the second revlog from a rev in the revlog,

        # we check revision against basemap.

        revlog.revlog.__init__(self, opener, indexfile)

        self.revlog2 = revlog2

        self.basemap = {} # mapping rev that is in revlog2 to ... nothing

        n = len(self)

        self.bundlerevs = set() # used by 'bundle()' revset expression

        for rev2 in self.revlog2:

            rev = self.revlog2.index[rev2]

            # rev numbers - in revlog2, very different from self.rev

            _start, _csize, _rsize, _base, linkrev, p1rev, p2rev, node = rev

            if linkmapper is None: # link is to same revlog

                assert linkrev == rev2 # we never link back

                link = n

            else: # rev must be mapped from repo2 cl to unified cl by linkmapper

                link = linkmapper(linkrev)

            if node in self.nodemap:

                # this happens for for the common revlog revisions

                self.bundlerevs.add(self.nodemap[node])

                continue

            p1node = self.revlog2.node(p1rev)

            p2node = self.revlog2.node(p2rev)

            e = (None, None, None, None,

                 link, self.rev(p1node), self.rev(p2node), node)

            self.basemap[n] = None

            self.index.insert(-1, e)

            self.nodemap[node] = n

            self.bundlerevs.add(n)

            n += 1

    def _chunk(self, rev):

        if rev not in self.basemap:

            return revlog.revlog._chunk(self, rev)

        return self.revlog2._chunk(self.node(rev))

    def revdiff(self, rev1, rev2):

        """return or calculate a delta between two revisions"""

        if rev1 in self.basemap and rev2 in self.basemap:

            return self.revlog2.revdiff(

                self.revlog2.rev(self.node(rev1)),

                self.revlog2.rev(self.node(rev2)))

        elif rev1 not in self.basemap and rev2 not in self.basemap:

            return revlog.revlog.revdiff(self, rev1, rev2)

        return mdiff.textdiff(self.revision(self.node(rev1)),

                              self.revision(self.node(rev2)))

    def revision(self, nodeorrev):

        """return an uncompressed revision of a given node or revision

        number.

        """

        if isinstance(nodeorrev, int):

            rev = nodeorrev

            node = self.node(rev)

        else:

            node = nodeorrev

            rev = self.rev(node)

        if node == nullid:

            return ""

        if rev in self.basemap:

            text = self.revlog2.revision(node)

            self._cache = (node, rev, text)

        else:

            text = revlog.revlog.revision(self, rev)

            # already cached

        return text

    def addrevision(self, text, transaction, link, p1=None, p2=None, d=None):

        raise NotImplementedError

    def addgroup(self, revs, linkmapper, transaction):

        raise NotImplementedError

    def strip(self, rev, minlink):

        raise NotImplementedError

    def checksize(self):

        raise NotImplementedError

class unionchangelog(unionrevlog, changelog.changelog):

    def __init__(self, opener, opener2):

        changelog.changelog.__init__(self, opener)

        linkmapper = None

        changelog2 = changelog.changelog(opener2)

        unionrevlog.__init__(self, opener, self.indexfile, changelog2,

                             linkmapper)

class unionmanifest(unionrevlog, manifest.manifest):

    def __init__(self, opener, opener2, linkmapper):

        manifest.manifest.__init__(self, opener)

        manifest2 = manifest.manifest(opener2)

        unionrevlog.__init__(self, opener, self.indexfile, manifest2,

                             linkmapper)

class unionfilelog(unionrevlog, filelog.filelog):

    def __init__(self, opener, path, opener2, linkmapper, repo):

        filelog.filelog.__init__(self, opener, path)

        filelog2 = filelog.filelog(opener2, path)

        unionrevlog.__init__(self, opener, self.indexfile, filelog2,

                             linkmapper)

        self._repo = repo

    def _file(self, f):

        self._repo.file(f)

class unionpeer(localrepo.localpeer):

    def canpush(self):

        return False

class unionrepository(localrepo.localrepository):

    def __init__(self, ui, path, path2):

        localrepo.localrepository.__init__(self, ui, path)

        self.ui.setconfig('phases', 'publish', False)

        self._url = 'union:%s+%s' % (util.expandpath(path),

                                     util.expandpath(path2))

        self.repo2 = localrepo.localrepository(ui, path2)

    @util.propertycache

    def changelog(self):

        return unionchangelog(self.sopener, self.repo2.sopener)

    def _clrev(self, rev2):

        """map from repo2 changelog rev to temporary rev in self.changelog"""

        node = self.repo2.changelog.node(rev2)

        return self.changelog.rev(node)

    @util.propertycache

    def manifest(self):

        return unionmanifest(self.sopener, self.repo2.sopener,

                             self._clrev)

    def url(self):

        return self._url

    def file(self, f):

        return unionfilelog(self.sopener, f, self.repo2.sopener,

                            self._clrev, self)

    def close(self):

        self.repo2.close()

    def cancopy(self):

        return False

    def peer(self):

        return unionpeer(self)

def instance(ui, path, create):

    u = util.url(path)

    assert u.scheme == 'union'

    repopath, repopath2 = u.path.split("+", 1)

    return unionrepository(ui, repopath, repopath2)