~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005 Canonical Ltd

#

# 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

"""Experiment in converting existing bzr branches to weaves."""

# To make this properly useful

#

# 1. assign text version ids, and put those text versions into

#    the inventory as they're converted.

#

# 2. keep track of the previous version of each file, rather than

#    just using the last one imported

#

# 3. assign entry versions when files are added, renamed or moved.

#

# 4. when merged-in versions are observed, walk down through them

#    to discover everything, then commit bottom-up

#

# 5. track ancestry as things are merged in, and commit that in each

#    revision

#

# Perhaps it's best to first walk the whole graph and make a plan for

# what should be imported in what order?  Need a kind of topological

# sort of all revisions.  (Or do we, can we just before doing a revision

# see that all its parents have either been converted or abandoned?)

# Cannot import a revision until all its parents have been

# imported.  in other words, we can only import revisions whose

# parents have all been imported.  the first step must be to

# import a revision with no parents, of which there must be at

# least one.  (So perhaps it's useful to store forward pointers

# from a list of parents to their children?)

#

# Another (equivalent?) approach is to build up the ordered

# ancestry list for the last revision, and walk through that.  We

# are going to need that.

#

# We don't want to have to recurse all the way back down the list.

#

# Suppose we keep a queue of the revisions able to be processed at

# any point.  This starts out with all the revisions having no

# parents.

#

# This seems like a generally useful algorithm...

#

# The current algorithm is dumb (O(n**2)?) but will do the job, and

# takes less than a second on the bzr.dev branch.

# This currently does a kind of lazy conversion of file texts, where a

# new text is written in every version.  That's unnecessary but for

# the moment saves us having to worry about when files need new

# versions.

import os

import tempfile

import sys

import shutil

from bzrlib.branch import Branch, find_branch

from bzrlib.branch import BZR_BRANCH_FORMAT_5, BZR_BRANCH_FORMAT_6

import bzrlib.hashcache as hashcache

from bzrlib.weave import Weave

from bzrlib.weavefile import read_weave, write_weave

from bzrlib.ui import ui_factory

from bzrlib.atomicfile import AtomicFile

from bzrlib.xml4 import serializer_v4

from bzrlib.xml5 import serializer_v5

from bzrlib.trace import mutter, note, warning

from bzrlib.osutils import sha_strings, sha_string, pathjoin, abspath

class Convert(object):

    def __init__(self, base_dir):

        self.base = base_dir

        self.converted_revs = set()

        self.absent_revisions = set()

        self.text_count = 0

        self.revisions = {}

        self.convert()

    def convert(self):

        if not self._open_branch():

            return

        note('starting upgrade of %s', os.path.abspath(self.base))

        self._backup_control_dir()

        self.pb = ui_factory.progress_bar()

        if self.old_format == 4:

            note('starting upgrade from format 4 to 5')

            self._convert_to_weaves()

            self._open_branch()

        if self.old_format == 5:

            note('starting upgrade from format 5 to 6')

            self._convert_to_prefixed()

            self._open_branch()

        cache = hashcache.HashCache(abspath(self.base))

        cache.clear()

        cache.write()

        note("finished")

    def _convert_to_prefixed(self):

        from bzrlib.store import hash_prefix

        for store_name in ["weaves", "revision-store"]:

            note("adding prefixes to %s" % store_name) 

            store_dir = pathjoin(self.base, ".bzr", store_name)

            for filename in os.listdir(store_dir):

                if filename.endswith(".weave") or filename.endswith(".gz"):

                    file_id = os.path.splitext(filename)[0]

                else:

                    file_id = filename

                prefix_dir = pathjoin(store_dir, hash_prefix(file_id))

                if not os.path.isdir(prefix_dir):

                    os.mkdir(prefix_dir)

                os.rename(pathjoin(store_dir, filename),

                          pathjoin(prefix_dir, filename))

        self._set_new_format(BZR_BRANCH_FORMAT_6)

    def _convert_to_weaves(self):

        note('note: upgrade may be faster if all store files are ungzipped first')

        if not os.path.isdir(self.base + '/.bzr/weaves'):

            os.mkdir(self.base + '/.bzr/weaves')

        self.inv_weave = Weave('inventory')

        # holds in-memory weaves for all files

        self.text_weaves = {}

        os.remove(self.branch.controlfilename('branch-format'))

        self._convert_working_inv()

        rev_history = self.branch.revision_history()

        # to_read is a stack holding the revisions we still need to process;

        # appending to it adds new highest-priority revisions

        self.known_revisions = set(rev_history)

        self.to_read = rev_history[-1:]

        while self.to_read:

            rev_id = self.to_read.pop()

            if (rev_id not in self.revisions

                and rev_id not in self.absent_revisions):

                self._load_one_rev(rev_id)

        self.pb.clear()

        to_import = self._make_order()

        for i, rev_id in enumerate(to_import):

            self.pb.update('converting revision', i, len(to_import))

            self._convert_one_rev(rev_id)

        self.pb.clear()

        note('upgraded to weaves:')

        note('  %6d revisions and inventories' % len(self.revisions))

        note('  %6d revisions not present' % len(self.absent_revisions))

        note('  %6d texts' % self.text_count)

        self._write_all_weaves()

        self._write_all_revs()

        self._cleanup_spare_files()

        self._set_new_format(BZR_BRANCH_FORMAT_5)

    def _open_branch(self):

        self.branch = Branch.open_downlevel(self.base)

        self.old_format = self.branch._branch_format

        if self.old_format == 6:

            note('this branch is in the most current format')

            return False

        if self.old_format not in (4, 5):

            raise BzrError("cannot upgrade from branch format %r" %

                           self.branch._branch_format)

        return True

    def _set_new_format(self, format):

        self.branch.put_controlfile('branch-format', format)

    def _cleanup_spare_files(self):

        for n in 'merged-patches', 'pending-merged-patches':

            p = self.branch.controlfilename(n)

            if not os.path.exists(p):

                continue

            ## assert os.path.getsize(p) == 0

            os.remove(p)

        shutil.rmtree(self.base + '/.bzr/inventory-store')

        shutil.rmtree(self.base + '/.bzr/text-store')

    def _backup_control_dir(self):

        orig = self.base + '/.bzr'

        backup = orig + '.backup'

        note('making backup of tree history')

        shutil.copytree(orig, backup)

        note('%s has been backed up to %s', orig, backup)

        note('if conversion fails, you can move this directory back to .bzr')

        note('if it succeeds, you can remove this directory if you wish')

    def _convert_working_inv(self):

        branch = self.branch

        inv = serializer_v4.read_inventory(branch.controlfile('inventory', 'rb'))

        new_inv_xml = serializer_v5.write_inventory_to_string(inv)

        branch.put_controlfile('inventory', new_inv_xml)

    def _write_all_weaves(self):

        write_a_weave(self.inv_weave, self.base + '/.bzr/inventory.weave')

        i = 0

        try:

            for file_id, file_weave in self.text_weaves.items():

                self.pb.update('writing weave', i, len(self.text_weaves))

                write_a_weave(file_weave, self.base + '/.bzr/weaves/%s.weave' % file_id)

                i += 1

        finally:

            self.pb.clear()

    def _write_all_revs(self):

        """Write all revisions out in new form."""

        shutil.rmtree(self.base + '/.bzr/revision-store')

        os.mkdir(self.base + '/.bzr/revision-store')

        try:

            for i, rev_id in enumerate(self.converted_revs):

                self.pb.update('write revision', i, len(self.converted_revs))

                f = file(self.base + '/.bzr/revision-store/%s' % rev_id, 'wb')

                try:

                    serializer_v5.write_revision(self.revisions[rev_id], f)

                finally:

                    f.close()

        finally:

            self.pb.clear()

    def _load_one_rev(self, rev_id):

        """Load a revision object into memory.

        Any parents not either loaded or abandoned get queued to be

        loaded."""

        self.pb.update('loading revision',

                       len(self.revisions),

                       len(self.known_revisions))

        if not self.branch.revision_store.has_id(rev_id):

            self.pb.clear()

            note('revision {%s} not present in branch; '

                 'will be converted as a ghost',

                 rev_id)

            self.absent_revisions.add(rev_id)

        else:

            rev_xml = self.branch.revision_store.get(rev_id).read()

            rev = serializer_v4.read_revision_from_string(rev_xml)

            for parent_id in rev.parent_ids:

                self.known_revisions.add(parent_id)

                self.to_read.append(parent_id)

            self.revisions[rev_id] = rev

    def _load_old_inventory(self, rev_id):

        assert rev_id not in self.converted_revs

        old_inv_xml = self.branch.inventory_store.get(rev_id).read()

        inv = serializer_v4.read_inventory_from_string(old_inv_xml)

        rev = self.revisions[rev_id]

        if rev.inventory_sha1:

            assert rev.inventory_sha1 == sha_string(old_inv_xml), \

                'inventory sha mismatch for {%s}' % rev_id

        return inv

    def _load_updated_inventory(self, rev_id):

        assert rev_id in self.converted_revs

        inv_xml = self.inv_weave.get_text(rev_id)

        inv = serializer_v5.read_inventory_from_string(inv_xml)

        return inv

    def _convert_one_rev(self, rev_id):

        """Convert revision and all referenced objects to new format."""

        rev = self.revisions[rev_id]

        inv = self._load_old_inventory(rev_id)

        present_parents = [p for p in rev.parent_ids

                           if p not in self.absent_revisions]

        self._convert_revision_contents(rev, inv, present_parents)

        self._store_new_weave(rev, inv, present_parents)

        self.converted_revs.add(rev_id)

    def _store_new_weave(self, rev, inv, present_parents):

        # the XML is now updated with text versions

        if __debug__:

            for file_id in inv:

                ie = inv[file_id]

                if ie.kind == 'root_directory':

                    continue

                assert hasattr(ie, 'revision'), \

                    'no revision on {%s} in {%s}' % \

                    (file_id, rev.revision_id)

        new_inv_xml = serializer_v5.write_inventory_to_string(inv)

        new_inv_sha1 = sha_string(new_inv_xml)

        self.inv_weave.add(rev.revision_id, 

                           present_parents,

                           new_inv_xml.splitlines(True),

                           new_inv_sha1)

        rev.inventory_sha1 = new_inv_sha1

    def _convert_revision_contents(self, rev, inv, present_parents):

        """Convert all the files within a revision.

        Also upgrade the inventory to refer to the text revision ids."""

        rev_id = rev.revision_id

        mutter('converting texts of revision {%s}',

               rev_id)

        parent_invs = map(self._load_updated_inventory, present_parents)

        for file_id in inv:

            ie = inv[file_id]

            self._convert_file_version(rev, ie, parent_invs)

    def _convert_file_version(self, rev, ie, parent_invs):

        """Convert one version of one file.

        The file needs to be added into the weave if it is a merge

        of >=2 parents or if it's changed from its parent.

        """

        if ie.kind == 'root_directory':

            return

        file_id = ie.file_id

        rev_id = rev.revision_id

        w = self.text_weaves.get(file_id)

        if w is None:

            w = Weave(file_id)

            self.text_weaves[file_id] = w

        text_changed = False

        previous_entries = ie.find_previous_heads(parent_invs, w)

        for old_revision in previous_entries:

                # if this fails, its a ghost ?

                assert old_revision in self.converted_revs 

        self.snapshot_ie(previous_entries, ie, w, rev_id)

        del ie.text_id

        assert getattr(ie, 'revision', None) is not None

    def snapshot_ie(self, previous_revisions, ie, w, rev_id):

        # TODO: convert this logic, which is ~= snapshot to

        # a call to:. This needs the path figured out. rather than a work_tree

        # a v4 revision_tree can be given, or something that looks enough like

        # one to give the file content to the entry if it needs it.

        # and we need something that looks like a weave store for snapshot to 

        # save against.

        #ie.snapshot(rev, PATH, previous_revisions, REVISION_TREE, InMemoryWeaveStore(self.text_weaves))

        if len(previous_revisions) == 1:

            previous_ie = previous_revisions.values()[0]

            if ie._unchanged(previous_ie):

                ie.revision = previous_ie.revision

                return

        parent_indexes = map(w.lookup, previous_revisions)

        if ie.has_text():

            file_lines = self.branch.text_store.get(ie.text_id).readlines()

            assert sha_strings(file_lines) == ie.text_sha1

            assert sum(map(len, file_lines)) == ie.text_size

            w.add(rev_id, parent_indexes, file_lines, ie.text_sha1)

            self.text_count += 1

        else:

            w.add(rev_id, parent_indexes, [], None)

        ie.revision = rev_id

        ##mutter('import text {%s} of {%s}',

        ##       ie.text_id, file_id)

    def _make_order(self):

        """Return a suitable order for importing revisions.

        The order must be such that an revision is imported after all

        its (present) parents.

        """

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

        done = self.absent_revisions.copy()

        o = []

        while todo:

            # scan through looking for a revision whose parents

            # are all done

            for rev_id in sorted(list(todo)):

                rev = self.revisions[rev_id]

                parent_ids = set(rev.parent_ids)

                if parent_ids.issubset(done):

                    # can take this one now

                    o.append(rev_id)

                    todo.remove(rev_id)

                    done.add(rev_id)

        return o

def write_a_weave(weave, filename):

    inv_wf = file(filename, 'wb')

    try:

        write_weave(weave, inv_wf)

    finally:

        inv_wf.close()

def upgrade(base_dir):

    Convert(base_dir)