~bzr-pqm/bzr/bzr.dev

# (C) 2005, 2006 Canonical Limited.

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""Reconcilers are able to fix some potential data errors in a branch."""

__all__ = ['reconcile', 'Reconciler', 'RepoReconciler', 'KnitReconciler']

from bzrlib import ui

from bzrlib.trace import mutter

from bzrlib.tsort import TopoSorter

def reconcile(dir, other=None):

    """Reconcile the data in dir.

    Currently this is limited to a inventory 'reweave'.

    This is a convenience method, for using a Reconciler object.

    Directly using Reconciler is recommended for library users that

    desire fine grained control or analysis of the found issues.

    :param other: another bzrdir to reconcile against.

    """

    reconciler = Reconciler(dir, other=other)

    reconciler.reconcile()

class Reconciler(object):

    """Reconcilers are used to reconcile existing data."""

    def __init__(self, dir, other=None):

        """Create a Reconciler."""

        self.bzrdir = dir

    def reconcile(self):

        """Perform reconciliation.

        After reconciliation the following attributes document found issues:

        inconsistent_parents: The number of revisions in the repository whose

                              ancestry was being reported incorrectly.

        garbage_inventories: The number of inventory objects without revisions

                             that were garbage collected.

        """

        self.pb = ui.ui_factory.nested_progress_bar()

        try:

            self._reconcile()

        finally:

            self.pb.finished()

    def _reconcile(self):

        """Helper function for performing reconciliation."""

        self.repo = self.bzrdir.find_repository()

        self.pb.note('Reconciling repository %s',

                     self.repo.bzrdir.root_transport.base)

        repo_reconciler = self.repo.reconcile(thorough=True)

        self.inconsistent_parents = repo_reconciler.inconsistent_parents

        self.garbage_inventories = repo_reconciler.garbage_inventories

        self.pb.note('Reconciliation complete.')

class RepoReconciler(object):

    """Reconciler that reconciles a repository.

    Currently this consists of an inventory reweave with revision cross-checks.

    """

    def __init__(self, repo, other=None, thorough=False):

        """Construct a RepoReconciler.

        :param thorough: perform a thorough check which may take longer but

                         will correct non-data loss issues such as incorrect

                         cached data.

        """

        self.garbage_inventories = 0

        self.inconsistent_parents = 0

        self.repo = repo

        self.thorough = thorough

    def reconcile(self):

        """Perform reconciliation.

        After reconciliation the following attributes document found issues:

        inconsistent_parents: The number of revisions in the repository whose

                              ancestry was being reported incorrectly.

        garbage_inventories: The number of inventory objects without revisions

                             that were garbage collected.

        """

        self.repo.lock_write()

        try:

            self.pb = ui.ui_factory.nested_progress_bar()

            try:

                self._reconcile_steps()

            finally:

                self.pb.finished()

        finally:

            self.repo.unlock()

    def _reconcile_steps(self):

        """Perform the steps to reconcile this repository."""

        self._reweave_inventory()

    def _reweave_inventory(self):

        """Regenerate the inventory weave for the repository from scratch.

        This is a smart function: it will only do the reweave if doing it 

        will correct data issues. The self.thorough flag controls whether

        only data-loss causing issues (!self.thorough) or all issues

        (self.thorough) are treated as requiring the reweave.

        """

        # local because needing to know about WeaveFile is a wart we want to hide

        from bzrlib.weave import WeaveFile, Weave

        transaction = self.repo.get_transaction()

        self.pb.update('Reading inventory data.')

        self.inventory = self.repo.get_inventory_weave()

        # the total set of revisions to process

        self.pending = set([rev_id for rev_id in self.repo._revision_store.all_revision_ids(transaction)])

        # mapping from revision_id to parents

        self._rev_graph = {}

        # errors that we detect

        self.inconsistent_parents = 0

        # we need the revision id of each revision and its available parents list

        self._setup_steps(len(self.pending))

        for rev_id in self.pending:

            # put a revision into the graph.

            self._graph_revision(rev_id)

        self._check_garbage_inventories()

        # if there are no inconsistent_parents and 

        # (no garbage inventories or we are not doing a thorough check)

        if (not self.inconsistent_parents and 

            (not self.garbage_inventories or not self.thorough)):

            self.pb.note('Inventory ok.')

            return

        self.pb.update('Backing up inventory...', 0, 0)

        self.repo.control_weaves.copy(self.inventory, 'inventory.backup', self.repo.get_transaction())

        self.pb.note('Backup Inventory created.')

        # asking for '' should never return a non-empty weave

        new_inventory_vf = self.repo.control_weaves.get_empty('inventory.new',

            self.repo.get_transaction())

        # we have topological order of revisions and non ghost parents ready.

        self._setup_steps(len(self._rev_graph))

        for rev_id in TopoSorter(self._rev_graph.items()).iter_topo_order():

            parents = self._rev_graph[rev_id]

            # double check this really is in topological order.

            unavailable = [p for p in parents if p not in new_inventory_vf]

            assert len(unavailable) == 0

            # this entry has all the non ghost parents in the inventory

            # file already.

            self._reweave_step('adding inventories')

            if isinstance(new_inventory_vf, WeaveFile):

                # It's really a WeaveFile, but we call straight into the

                # Weave's add method to disable the auto-write-out behaviour.

                # This is done to avoid a revision_count * time-to-write additional overhead on 

                # reconcile.

                new_inventory_vf._check_write_ok()

                Weave._add_lines(new_inventory_vf, rev_id, parents, self.inventory.get_lines(rev_id),

                                 None)

            else:

                new_inventory_vf.add_lines(rev_id, parents, self.inventory.get_lines(rev_id))

        if isinstance(new_inventory_vf, WeaveFile):

            new_inventory_vf._save()

        # if this worked, the set of new_inventory_vf.names should equal

        # self.pending

        assert set(new_inventory_vf.versions()) == self.pending

        self.pb.update('Writing weave')

        self.repo.control_weaves.copy(new_inventory_vf, 'inventory', self.repo.get_transaction())

        self.repo.control_weaves.delete('inventory.new', self.repo.get_transaction())

        self.inventory = None

        self.pb.note('Inventory regenerated.')

    def _setup_steps(self, new_total):

        """Setup the markers we need to control the progress bar."""

        self.total = new_total

        self.count = 0

    def _graph_revision(self, rev_id):

        """Load a revision into the revision graph."""

        # pick a random revision

        # analyse revision id rev_id and put it in the stack.

        self._reweave_step('loading revisions')

        rev = self.repo.get_revision_reconcile(rev_id)

        assert rev.revision_id == rev_id

        parents = []

        for parent in rev.parent_ids:

            if self._parent_is_available(parent):

                parents.append(parent)

            else:

                mutter('found ghost %s', parent)

        self._rev_graph[rev_id] = parents   

        if self._parents_are_inconsistent(rev_id, parents):

            self.inconsistent_parents += 1

            mutter('Inconsistent inventory parents: id {%s} '

                   'inventory claims %r, '

                   'available parents are %r, '

                   'unavailable parents are %r',

                   rev_id, 

                   set(self.inventory.get_parents(rev_id)),

                   set(parents),

                   set(rev.parent_ids).difference(set(parents)))

    def _parents_are_inconsistent(self, rev_id, parents):

        """Return True if the parents list of rev_id does not match the weave.

        This detects inconsistencies based on the self.thorough value:

        if thorough is on, the first parent value is checked as well as ghost

        differences.

        Otherwise only the ghost differences are evaluated.

        """

        weave_parents = self.inventory.get_parents(rev_id)

        weave_missing_old_ghosts = set(weave_parents) != set(parents)

        first_parent_is_wrong = (

            len(weave_parents) and len(parents) and

            parents[0] != weave_parents[0])

        if self.thorough:

            return weave_missing_old_ghosts or first_parent_is_wrong

        else:

            return weave_missing_old_ghosts

    def _check_garbage_inventories(self):

        """Check for garbage inventories which we cannot trust

        We cant trust them because their pre-requisite file data may not

        be present - all we know is that their revision was not installed.

        """

        if not self.thorough:

            return

        inventories = set(self.inventory.versions())

        revisions = set(self._rev_graph.keys())

        garbage = inventories.difference(revisions)

        self.garbage_inventories = len(garbage)

        for revision_id in garbage:

            mutter('Garbage inventory {%s} found.', revision_id)

    def _parent_is_available(self, parent):

        """True if parent is a fully available revision

        A fully available revision has a inventory and a revision object in the

        repository.

        """

        return (parent in self._rev_graph or 

                (parent in self.inventory and self.repo.has_revision(parent)))

    def _reweave_step(self, message):

        """Mark a single step of regeneration complete."""

        self.pb.update(message, self.count, self.total)

        self.count += 1

class KnitReconciler(RepoReconciler):

    """Reconciler that reconciles a knit format repository.

    This will detect garbage inventories and remove them.

    Inconsistent parentage is checked for in the revision weave.

    """

    def _reconcile_steps(self):

        """Perform the steps to reconcile this repository."""

        if self.thorough:

            self._load_indexes()

            # knits never suffer this

            self._gc_inventory()

    def _load_indexes(self):

        """Load indexes for the reconciliation."""

        self.transaction = self.repo.get_transaction()

        self.pb.update('Reading indexes.', 0, 2)

        self.inventory = self.repo.get_inventory_weave()

        self.pb.update('Reading indexes.', 1, 2)

        self.revisions = self.repo._revision_store.get_revision_file(self.transaction)

        self.pb.update('Reading indexes.', 2, 2)

    def _gc_inventory(self):

        """Remove inventories that are not referenced from the revision store."""

        self.pb.update('Checking unused inventories.', 0, 1)

        self._check_garbage_inventories()

        self.pb.update('Checking unused inventories.', 1, 3)

        if not self.garbage_inventories:

            self.pb.note('Inventory ok.')

            return

        self.pb.update('Backing up inventory...', 0, 0)

        self.repo.control_weaves.copy(self.inventory, 'inventory.backup', self.transaction)

        self.pb.note('Backup Inventory created.')

        # asking for '' should never return a non-empty weave

        new_inventory_vf = self.repo.control_weaves.get_empty('inventory.new',

            self.transaction)

        # we have topological order of revisions and non ghost parents ready.

        self._setup_steps(len(self.revisions))

        for rev_id in TopoSorter(self.revisions.get_graph().items()).iter_topo_order():

            parents = self.revisions.get_parents(rev_id)

            # double check this really is in topological order.

            unavailable = [p for p in parents if p not in new_inventory_vf]

            assert len(unavailable) == 0

            # this entry has all the non ghost parents in the inventory

            # file already.

            self._reweave_step('adding inventories')

            # ugly but needed, weaves are just way tooooo slow else.

            new_inventory_vf.add_lines(rev_id, parents, self.inventory.get_lines(rev_id))

        # if this worked, the set of new_inventory_vf.names should equal

        # self.pending

        assert set(new_inventory_vf.versions()) == set(self.revisions.versions())

        self.pb.update('Writing weave')

        self.repo.control_weaves.copy(new_inventory_vf, 'inventory', self.transaction)

        self.repo.control_weaves.delete('inventory.new', self.transaction)

        self.inventory = None

        self.pb.note('Inventory regenerated.')

    def _check_garbage_inventories(self):

        """Check for garbage inventories which we cannot trust

        We cant trust them because their pre-requisite file data may not

        be present - all we know is that their revision was not installed.

        """

        inventories = set(self.inventory.versions())

        revisions = set(self.revisions.versions())

        garbage = inventories.difference(revisions)

        self.garbage_inventories = len(garbage)

        for revision_id in garbage:

            mutter('Garbage inventory {%s} found.', revision_id)