# context.py - changeset and file context objects for mercurial

#

# Copyright 2006 Matt Mackall <mpm@selenic.com>

#

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

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

from node import *

from demandload import demandload

demandload(globals(), "ancestor util")

class changectx(object):

    """A changecontext object makes access to data related to a particular

    changeset convenient."""

    def __init__(self, repo, changeid=None):

        """changeid is a revision number, node, or tag"""

        self._repo = repo

        if not changeid and changeid != 0:

            p1, p2 = self._repo.dirstate.parents()

            self._rev = self._repo.changelog.rev(p1)

            if self._rev == -1:

                changeid = 'tip'

            else:

                self._node = p1

                return

        self._node = self._repo.lookup(changeid)

        self._rev = self._repo.changelog.rev(self._node)

    def __repr__(self):

        return "<changectx %s>" % short(self.node())

    def changeset(self):

        try:

            return self._changeset

        except AttributeError:

            self._changeset = self._repo.changelog.read(self.node())

            return self._changeset

    def manifest(self):

        try:

            return self._manifest

        except AttributeError:

            self._manifest = self._repo.manifest.read(self.changeset()[0])

            return self._manifest

    def rev(self): return self._rev

    def node(self): return self._node

    def user(self): return self.changeset()[1]

    def date(self): return self.changeset()[2]

    def files(self): return self.changeset()[3]

    def description(self): return self.changeset()[4]

    def parents(self):

        """return contexts for each parent changeset"""

        p = self._repo.changelog.parents(self._node)

        return [ changectx(self._repo, x) for x in p ]

    def children(self):

        """return contexts for each child changeset"""

        c = self._repo.changelog.children(self._node)

        return [ changectx(self._repo, x) for x in c ]

    def filenode(self, path):

        node, flag = self._repo.manifest.find(self.changeset()[0], path)

        return node

    def filectx(self, path, fileid=None):

        """get a file context from this changeset"""

        if fileid is None:

            fileid = self.filenode(path)

        return filectx(self._repo, path, fileid=fileid)

    def filectxs(self):

        """generate a file context for each file in this changeset's

           manifest"""

        mf = self.manifest()

        m = mf.keys()

        m.sort()

        for f in m:

            yield self.filectx(f, fileid=mf[f])

    def ancestor(self, c2):

        """

        return the ancestor context of self and c2

        """

        n = self._repo.changelog.ancestor(self._node, c2._node)

        return changectx(self._repo, n)

class filectx(object):

    """A filecontext object makes access to data related to a particular

       filerevision convenient."""

    def __init__(self, repo, path, changeid=None, fileid=None, filelog=None):

        """changeid can be a changeset revision, node, or tag.

           fileid can be a file revision or node."""

        self._repo = repo

        self._path = path

        assert changeid is not None or fileid is not None

        if filelog:

            self._filelog = filelog

        else:

            self._filelog = self._repo.file(self._path)

        if fileid is None:

            self._changeid = changeid

        else:

            self._filenode = self._filelog.lookup(fileid)

            self._changeid = self._filelog.linkrev(self._filenode)

    def __getattr__(self, name):

        if name == '_changectx':

            self._changectx = changectx(self._repo, self._changeid)

            return self._changectx

        elif name == '_filenode':

            self._filenode = self._changectx.filenode(self._path)

            return self._filenode

        elif name == '_filerev':

            self._filerev = self._filelog.rev(self._filenode)

            return self._filerev

        else:

            raise AttributeError, name

    def __repr__(self):

        return "<filectx %s@%s>" % (self.path(), short(self.node()))

    def filerev(self): return self._filerev

    def filenode(self): return self._filenode

    def filelog(self): return self._filelog

    def rev(self):

        if hasattr(self, "_changectx"):

            return self._changectx.rev()

        return self._filelog.linkrev(self._filenode)

    def node(self): return self._changectx.node()

    def user(self): return self._changectx.user()

    def date(self): return self._changectx.date()

    def files(self): return self._changectx.files()

    def description(self): return self._changectx.description()

    def manifest(self): return self._changectx.manifest()

    def changectx(self): return self._changectx

    def data(self): return self._filelog.read(self._filenode)

    def renamed(self): return self._filelog.renamed(self._filenode)

    def path(self): return self._path

    def parents(self):

        p = self._path

        fl = self._filelog

        pl = [ (p, n, fl) for n in self._filelog.parents(self._filenode) ]

        r = self.renamed()

        if r:

            pl[0] = (r[0], r[1], None)

        return [ filectx(self._repo, p, fileid=n, filelog=l)

                 for p,n,l in pl if n != nullid ]

    def children(self):

        # hard for renames

        c = self._filelog.children(self._filenode)

        return [ filectx(self._repo, self._path, fileid=x,

                         filelog=self._filelog) for x in c ]

    def ancestor(self, fc2):

        """

        find the common ancestor file context, if any, of self, and fc2

        """

        acache = {}

        flcache = {self._path:self._filelog, fc2._path:fc2._filelog}

        def parents(vertex):

            if vertex in acache:

                return acache[vertex]

            f, n = vertex

            if f not in flcache:

                flcache[f] = self._repo.file(f)

            fl = flcache[f]

            pl = [ (f,p) for p in fl.parents(n) if p != nullid ]

            re = fl.renamed(n)

            if re:

                pl.append(re)

            acache[vertex]=pl

            return pl

        a, b = (self._path, self._filenode), (fc2._path, fc2._filenode)

        v = ancestor.ancestor(a, b, parents)

        if v:

            f,n = v

            return filectx(self._repo, f, fileid=n, filelog=flcache[f])

        return None