~bzr-pqm/bzr/bzr.dev

#! /usr/bin/python

# 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

# XXX: Some consideration of the problems that might occur if there are

# files whose id differs only in case.  That should probably be forbidden.

import errno

import os

from cStringIO import StringIO

import urllib

from bzrlib.weavefile import read_weave, write_weave_v5

from bzrlib.weave import Weave

from bzrlib.store import TransportStore, hash_prefix

from bzrlib.atomicfile import AtomicFile

from bzrlib.errors import NoSuchFile, FileExists

from bzrlib.trace import mutter

class WeaveStore(TransportStore):

    """Collection of several weave files in a directory.

    This has some shortcuts for reading and writing them.

    """

    FILE_SUFFIX = '.weave'

    def __init__(self, transport, prefixed=False, precious=False,

                 dir_mode=None, file_mode=None):

        super(WeaveStore, self).__init__(transport,

                dir_mode=dir_mode, file_mode=file_mode,

                prefixed=prefixed, compressed=False)

        self._precious = precious

    def filename(self, file_id):

        """Return the path relative to the transport root."""

        if self._prefixed:

            return hash_prefix(file_id) + urllib.quote(file_id) + WeaveStore.FILE_SUFFIX

        else:

            return urllib.quote(file_id) + WeaveStore.FILE_SUFFIX

    def __iter__(self):

        l = len(WeaveStore.FILE_SUFFIX)

        for relpath in self._iter_files_recursive():

            if relpath.endswith(WeaveStore.FILE_SUFFIX):

                yield os.path.basename(relpath[:-l])

    def has_id(self, fileid):

        return self._transport.has(self.filename(fileid))

    def _get(self, file_id):

        return self._transport.get(self.filename(file_id))

    def _put(self, file_id, f):

        if self._prefixed:

            try:

                self._transport.mkdir(hash_prefix(file_id), mode=self._dir_mode)

            except FileExists:

                pass

        return self._transport.put(self.filename(file_id), f, mode=self._file_mode)

    def get_weave(self, file_id, transaction):

        weave = transaction.map.find_weave(file_id)

        if weave:

            mutter("cache hit in %s for %s", self, file_id)

            return weave

        w = read_weave(self._get(file_id))

        transaction.map.add_weave(file_id, w)

        transaction.register_clean(w, precious=self._precious)

        # TODO: jam 20051219 This should check if there is a prelude

        #       which is already cached, and if so, should remove it

        #       But transaction doesn't seem to have a 'remove'

        #       One workaround would be to re-add the object with

        #       the PRELUDE marker.

        return w

    def get_weave_prelude(self, file_id, transaction):

        weave_id = file_id

        weave = transaction.map.find_weave(weave_id)

        if weave:

            mutter("cache hit in %s for %s", self, weave_id)

            return weave

        # We want transactions to also cache preludes if that

        # is all that we are loading. So we need a unique

        # identifier, so that someone who wants the whole text

        # won't get just the prelude

        weave_id = 'PRELUDE-' + file_id

        weave = transaction.map.find_weave(weave_id)

        if weave:

            mutter("cache hit in %s for %s", self, weave_id)

            return weave

        w = read_weave(self._get(file_id), prelude=True)

        transaction.map.add_weave(weave_id, w)

        transaction.register_clean(w, precious=self._precious)

        return w

    def get_lines(self, file_id, rev_id, transaction):

        """Return text from a particular version of a weave.

        Returned as a list of lines."""

        w = self.get_weave(file_id, transaction)

        return w.get(w.lookup(rev_id))

    def get_weave_prelude_or_empty(self, file_id, transaction):

        """cheap version that reads the prelude but not the lines

        """

        try:

            return self.get_weave_prelude(file_id, transaction)

        except NoSuchFile:

            # We can cache here, because we know that there

            # is no complete object, since we got NoSuchFile

            weave = Weave(weave_name=file_id)

            transaction.map.add_weave(file_id, weave)

            transaction.register_clean(weave, precious=self._precious)

            return weave

    def get_weave_or_empty(self, file_id, transaction):

        """Return a weave, or an empty one if it doesn't exist.""" 

        try:

            return self.get_weave(file_id, transaction)

        except NoSuchFile:

            weave = Weave(weave_name=file_id)

            transaction.map.add_weave(file_id, weave)

            transaction.register_clean(weave, precious=self._precious)

            return weave

    def put_weave(self, file_id, weave, transaction):

        """Write back a modified weave"""

        transaction.register_dirty(weave)

        # TODO FOR WRITE TRANSACTIONS: this should be done in a callback

        # from the transaction, when it decides to save.

        sio = StringIO()

        write_weave_v5(weave, sio)

        sio.seek(0)

        self._put(file_id, sio)

    def add_text(self, file_id, rev_id, new_lines, parents, transaction):

        w = self.get_weave_or_empty(file_id, transaction)

        parent_idxs = map(w.lookup, parents)

        w.add(rev_id, parent_idxs, new_lines)

        self.put_weave(file_id, w, transaction)

    def add_identical_text(self, file_id, old_rev_id, new_rev_id, parents,

                           transaction):

        w = self.get_weave_or_empty(file_id, transaction)

        parent_idxs = map(w.lookup, parents)

        w.add_identical(old_rev_id, new_rev_id, parent_idxs)

        self.put_weave(file_id, w, transaction)

    def copy_multi(self, from_store, file_ids):

        assert isinstance(from_store, WeaveStore)

        for f in file_ids:

            mutter("copy weave {%s} into %s", f, self)

            self._put(f, from_store._get(f))