hgext/convert/bzr.py

convert/bzr: make it work with filemaps (issue1631)

The bzr converter maintains a child -> parents mapping and drop entries
whenever a child is read. It does not work with filemaps, getchangedfiles() may
be called more than once when filtered files belong to merge revisions.
getchanges() still works that way but it is not clear whether a similar issue
can arise when interacting with merges.

# bzr support for the convert extension
# This module is for handling 'bzr', that was formerly known as Bazaar-NG;
# it cannot access 'bar' repositories, but they were never used very much

import os
from mercurial import demandimport
# these do not work with demandimport, blacklist
demandimport.ignore.extend([
        'bzrlib.transactions',
        'bzrlib.urlutils',
    ])

from mercurial.i18n import _
from mercurial import util
from common import NoRepo, commit, converter_source

try:
    # bazaar imports
    from bzrlib import branch, revision, errors
    from bzrlib.revisionspec import RevisionSpec
except ImportError:
    pass

supportedkinds = ('file', 'symlink')

class bzr_source(converter_source):
    """Reads Bazaar repositories by using the Bazaar Python libraries"""

    def __init__(self, ui, path, rev=None):
        super(bzr_source, self).__init__(ui, path, rev=rev)

        try:
            # access bzrlib stuff
            branch
        except NameError:
            raise NoRepo('Bazaar modules could not be loaded')

        if not os.path.exists(os.path.join(path, '.bzr')):
            raise NoRepo('%s does not look like a Bazaar repo' % path)

        path = os.path.abspath(path)
        self.branch = branch.Branch.open(path)
        self.sourcerepo = self.branch.repository
        self._parentids = {}

    def before(self):
        """Before the conversion begins, acquire a read lock
        for all the operations that might need it. Fortunately
        read locks don't block other reads or writes to the
        repository, so this shouldn't have any impact on the usage of
        the source repository.

        The alternative would be locking on every operation that
        needs locks (there are currently two: getting the file and
        getting the parent map) and releasing immediately after,
        but this approach can take even 40% longer."""
        self.sourcerepo.lock_read()

    def after(self):
        self.sourcerepo.unlock()

    def getheads(self):
        if not self.rev:
            return [self.branch.last_revision()]
        try:
            r = RevisionSpec.from_string(self.rev)
            info = r.in_history(self.branch)
        except errors.BzrError:
            raise util.Abort(_('%s is not a valid revision in current branch')
                             % self.rev)
        return [info.rev_id]

    def getfile(self, name, rev):
        revtree = self.sourcerepo.revision_tree(rev)
        fileid = revtree.path2id(name)
        if fileid is None or revtree.kind(fileid) not in supportedkinds:
            # the file is not available anymore - was deleted
            raise IOError(_('%s is not available in %s anymore') %
                    (name, rev))
        sio = revtree.get_file(fileid)
        return sio.read()

    def getmode(self, name, rev):
        return self._modecache[(name, rev)]

    def getchanges(self, version):
        # set up caches: modecache and revtree
        self._modecache = {}
        self._revtree = self.sourcerepo.revision_tree(version)
        # get the parentids from the cache
        parentids = self._parentids.pop(version)
        # only diff against first parent id
        prevtree = self.sourcerepo.revision_tree(parentids[0])
        return self._gettreechanges(self._revtree, prevtree)

    def getcommit(self, version):
        rev = self.sourcerepo.get_revision(version)
        # populate parent id cache
        if not rev.parent_ids:
            parents = []
            self._parentids[version] = (revision.NULL_REVISION,)
        else:
            parents = self._filterghosts(rev.parent_ids)
            self._parentids[version] = parents

        return commit(parents=parents,
                # bzr uses 1 second timezone precision
                date='%d %d' % (rev.timestamp, rev.timezone / 3600),
                author=self.recode(rev.committer),
                # bzr returns bytestrings or unicode, depending on the content
                desc=self.recode(rev.message),
                rev=version)

    def gettags(self):
        if not self.branch.supports_tags():
            return {}
        tagdict = self.branch.tags.get_tag_dict()
        bytetags = {}
        for name, rev in tagdict.iteritems():
            bytetags[self.recode(name)] = rev
        return bytetags

    def getchangedfiles(self, rev, i):
        self._modecache = {}
        curtree = self.sourcerepo.revision_tree(rev)
        if i is not None:
            parentid = self._parentids[rev][i]
        else:
            # no parent id, get the empty revision
            parentid = revision.NULL_REVISION

        prevtree = self.sourcerepo.revision_tree(parentid)
        changes = [e[0] for e in self._gettreechanges(curtree, prevtree)[0]]
        return changes

    def _gettreechanges(self, current, origin):
        revid = current._revision_id;
        changes = []
        renames = {}
        for (fileid, paths, changed_content, versioned, parent, name,
            kind, executable) in current.iter_changes(origin):

            if paths[0] == u'' or paths[1] == u'':
                # ignore changes to tree root
                continue

            # bazaar tracks directories, mercurial does not, so
            # we have to rename the directory contents
            if kind[1] == 'directory':
                if kind[0] not in (None, 'directory'):
                    # Replacing 'something' with a directory, record it
                    # so it can be removed.
                    changes.append((self.recode(paths[0]), revid))

                if None not in paths and paths[0] != paths[1]:
                    # neither an add nor an delete - a move
                    # rename all directory contents manually
                    subdir = origin.inventory.path2id(paths[0])
                    # get all child-entries of the directory
                    for name, entry in origin.inventory.iter_entries(subdir):
                        # hg does not track directory renames
                        if entry.kind == 'directory':
                            continue
                        frompath = self.recode(paths[0] + '/' + name)
                        topath = self.recode(paths[1] + '/' + name)
                        # register the files as changed
                        changes.append((frompath, revid))
                        changes.append((topath, revid))
                        # add to mode cache
                        mode = ((entry.executable and 'x') or (entry.kind == 'symlink' and 's')
                                or '')
                        self._modecache[(topath, revid)] = mode
                        # register the change as move
                        renames[topath] = frompath

                # no futher changes, go to the next change
                continue

            # we got unicode paths, need to convert them
            path, topath = [self.recode(part) for part in paths]

            if topath is None:
                # file deleted
                changes.append((path, revid))
                continue

            # renamed
            if path and path != topath:
                renames[topath] = path
                changes.append((path, revid))

            # populate the mode cache
            kind, executable = [e[1] for e in (kind, executable)]
            mode = ((executable and 'x') or (kind == 'symlink' and 'l')
                    or '')
            self._modecache[(topath, revid)] = mode
            changes.append((topath, revid))

        return changes, renames

    def _filterghosts(self, ids):
        """Filters out ghost revisions which hg does not support, see
        <http://bazaar-vcs.org/GhostRevision>
        """
        parentmap = self.sourcerepo.get_parent_map(ids)
        parents = tuple([parent for parent in ids if parent in parentmap])
        return parents

    def recode(self, s, encoding=None):
        """This version of recode tries to encode unicode to bytecode,
        and preferably using the UTF-8 codec.
        Other types than Unicode are silently returned, this is by
        intention, e.g. the None-type is not going to be encoded but instead
        just passed through
        """
        if not encoding:
            encoding = self.encoding or 'utf-8'

        if isinstance(s, unicode):
            return s.encode(encoding)
        else:
            # leave it alone
            return s