~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005, 2006 Canonical Ltd

#

# Authors:

#   Johan Rydberg <jrydberg@gnu.org>

#

# 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

"""Versioned text file storage api."""

from bzrlib.lazy_import import lazy_import

lazy_import(globals(), """

from bzrlib import (

    errors,

    osutils,

    multiparent,

    tsort,

    revision,

    ui,

    )

from bzrlib.graph import Graph

from bzrlib.transport.memory import MemoryTransport

""")

from cStringIO import StringIO

from bzrlib.inter import InterObject

from bzrlib.symbol_versioning import *

from bzrlib.textmerge import TextMerge

class VersionedFile(object):

    """Versioned text file storage.

    A versioned file manages versions of line-based text files,

    keeping track of the originating version for each line.

    To clients the "lines" of the file are represented as a list of

    strings. These strings will typically have terminal newline

    characters, but this is not required.  In particular files commonly

    do not have a newline at the end of the file.

    Texts are identified by a version-id string.

    """

    @staticmethod

    def check_not_reserved_id(version_id):

        revision.check_not_reserved_id(version_id)

    def copy_to(self, name, transport):

        """Copy this versioned file to name on transport."""

        raise NotImplementedError(self.copy_to)

    def versions(self):

        """Return a unsorted list of versions."""

        raise NotImplementedError(self.versions)

    @deprecated_method(one_four)

    def has_ghost(self, version_id):

        """Returns whether version is present as a ghost."""

        raise NotImplementedError(self.has_ghost)

    def has_version(self, version_id):

        """Returns whether version is present."""

        raise NotImplementedError(self.has_version)

    def add_lines(self, version_id, parents, lines, parent_texts=None,

        left_matching_blocks=None, nostore_sha=None, random_id=False,

        check_content=True):

        """Add a single text on top of the versioned file.

        Must raise RevisionAlreadyPresent if the new version is

        already present in file history.

        Must raise RevisionNotPresent if any of the given parents are

        not present in file history.

        :param lines: A list of lines. Each line must be a bytestring. And all

            of them except the last must be terminated with \n and contain no

            other \n's. The last line may either contain no \n's or a single

            terminated \n. If the lines list does meet this constraint the add

            routine may error or may succeed - but you will be unable to read

            the data back accurately. (Checking the lines have been split

            correctly is expensive and extremely unlikely to catch bugs so it

            is not done at runtime unless check_content is True.)

        :param parent_texts: An optional dictionary containing the opaque 

            representations of some or all of the parents of version_id to

            allow delta optimisations.  VERY IMPORTANT: the texts must be those

            returned by add_lines or data corruption can be caused.

        :param left_matching_blocks: a hint about which areas are common

            between the text and its left-hand-parent.  The format is

            the SequenceMatcher.get_matching_blocks format.

        :param nostore_sha: Raise ExistingContent and do not add the lines to

            the versioned file if the digest of the lines matches this.

        :param random_id: If True a random id has been selected rather than

            an id determined by some deterministic process such as a converter

            from a foreign VCS. When True the backend may choose not to check

            for uniqueness of the resulting key within the versioned file, so

            this should only be done when the result is expected to be unique

            anyway.

        :param check_content: If True, the lines supplied are verified to be

            bytestrings that are correctly formed lines.

        :return: The text sha1, the number of bytes in the text, and an opaque

                 representation of the inserted version which can be provided

                 back to future add_lines calls in the parent_texts dictionary.

        """

        self._check_write_ok()

        return self._add_lines(version_id, parents, lines, parent_texts,

            left_matching_blocks, nostore_sha, random_id, check_content)

    def _add_lines(self, version_id, parents, lines, parent_texts,

        left_matching_blocks, nostore_sha, random_id, check_content):

        """Helper to do the class specific add_lines."""

        raise NotImplementedError(self.add_lines)

    def add_lines_with_ghosts(self, version_id, parents, lines,

        parent_texts=None, nostore_sha=None, random_id=False,

        check_content=True, left_matching_blocks=None):

        """Add lines to the versioned file, allowing ghosts to be present.

        This takes the same parameters as add_lines and returns the same.

        """

        self._check_write_ok()

        return self._add_lines_with_ghosts(version_id, parents, lines,

            parent_texts, nostore_sha, random_id, check_content, left_matching_blocks)

    def _add_lines_with_ghosts(self, version_id, parents, lines, parent_texts,

        nostore_sha, random_id, check_content, left_matching_blocks):

        """Helper to do class specific add_lines_with_ghosts."""

        raise NotImplementedError(self.add_lines_with_ghosts)

    def check(self, progress_bar=None):

        """Check the versioned file for integrity."""

        raise NotImplementedError(self.check)

    def _check_lines_not_unicode(self, lines):

        """Check that lines being added to a versioned file are not unicode."""

        for line in lines:

            if line.__class__ is not str:

                raise errors.BzrBadParameterUnicode("lines")

    def _check_lines_are_lines(self, lines):

        """Check that the lines really are full lines without inline EOL."""

        for line in lines:

            if '\n' in line[:-1]:

                raise errors.BzrBadParameterContainsNewline("lines")

    @deprecated_method(one_four)

    def enable_cache(self):

        """Tell this versioned file that it should cache any data it reads.

        This is advisory, implementations do not have to support caching.

        """

        pass

    @deprecated_method(one_four)

    def clear_cache(self):

        """Remove any data cached in the versioned file object.

        This only needs to be supported if caches are supported

        """

        pass

    @deprecated_method(one_four)

    def clone_text(self, new_version_id, old_version_id, parents):

        """Add an identical text to old_version_id as new_version_id.

        Must raise RevisionNotPresent if the old version or any of the

        parents are not present in file history.

        Must raise RevisionAlreadyPresent if the new version is

        already present in file history."""

        self._check_write_ok()

        return self.add_lines(new_version_id, parents,

            self.get_lines(old_version_id))

    def get_format_signature(self):

        """Get a text description of the data encoding in this file.

        :since: 0.90

        """

        raise NotImplementedError(self.get_format_signature)

    def make_mpdiffs(self, version_ids):

        """Create multiparent diffs for specified versions."""

        knit_versions = set()

        knit_versions.update(version_ids)

        parent_map = self.get_parent_map(version_ids)

        for version_id in version_ids:

            try:

                knit_versions.update(parent_map[version_id])

            except KeyError:

                raise RevisionNotPresent(version_id, self)

        # We need to filter out ghosts, because we can't diff against them.

        knit_versions = set(self.get_parent_map(knit_versions).keys())

        lines = dict(zip(knit_versions,

            self._get_lf_split_line_list(knit_versions)))

        diffs = []

        for version_id in version_ids:

            target = lines[version_id]

            try:

                parents = [lines[p] for p in parent_map[version_id] if p in

                    knit_versions]

            except KeyError:

                raise RevisionNotPresent(version_id, self)

            if len(parents) > 0:

                left_parent_blocks = self._extract_blocks(version_id,

                                                          parents[0], target)

            else:

                left_parent_blocks = None

            diffs.append(multiparent.MultiParent.from_lines(target, parents,

                         left_parent_blocks))

        return diffs

    def _extract_blocks(self, version_id, source, target):

        return None

    def add_mpdiffs(self, records):

        """Add mpdiffs to this VersionedFile.

        Records should be iterables of version, parents, expected_sha1,

        mpdiff. mpdiff should be a MultiParent instance.

        """

        # Does this need to call self._check_write_ok()? (IanC 20070919)

        vf_parents = {}

        mpvf = multiparent.MultiMemoryVersionedFile()

        versions = []

        for version, parent_ids, expected_sha1, mpdiff in records:

            versions.append(version)

            mpvf.add_diff(mpdiff, version, parent_ids)

        needed_parents = set()

        for version, parent_ids, expected_sha1, mpdiff in records:

            needed_parents.update(p for p in parent_ids

                                  if not mpvf.has_version(p))

        present_parents = set(self.get_parent_map(needed_parents).keys())

        for parent_id, lines in zip(present_parents,

                                 self._get_lf_split_line_list(present_parents)):

            mpvf.add_version(lines, parent_id, [])

        for (version, parent_ids, expected_sha1, mpdiff), lines in\

            zip(records, mpvf.get_line_list(versions)):

            if len(parent_ids) == 1:

                left_matching_blocks = list(mpdiff.get_matching_blocks(0,

                    mpvf.get_diff(parent_ids[0]).num_lines()))

            else:

                left_matching_blocks = None

            try:

                _, _, version_text = self.add_lines_with_ghosts(version,

                    parent_ids, lines, vf_parents,

                    left_matching_blocks=left_matching_blocks)

            except NotImplementedError:

                # The vf can't handle ghosts, so add lines normally, which will

                # (reasonably) fail if there are ghosts in the data.

                _, _, version_text = self.add_lines(version,

                    parent_ids, lines, vf_parents,

                    left_matching_blocks=left_matching_blocks)

            vf_parents[version] = version_text

        for (version, parent_ids, expected_sha1, mpdiff), sha1 in\

             zip(records, self.get_sha1s(versions)):

            if expected_sha1 != sha1:

                raise errors.VersionedFileInvalidChecksum(version)

    @deprecated_method(one_four)

    def get_sha1(self, version_id):

        """Get the stored sha1 sum for the given revision.

        :param version_id: The name of the version to lookup

        """

        return self.get_sha1s([version_id])[0]

    def get_sha1s(self, version_ids):

        """Get the stored sha1 sums for the given revisions.

        :param version_ids: The names of the versions to lookup

        :return: a list of sha1s in order according to the version_ids

        """

        raise NotImplementedError(self.get_sha1s)

    def get_text(self, version_id):

        """Return version contents as a text string.

        Raises RevisionNotPresent if version is not present in

        file history.

        """

        return ''.join(self.get_lines(version_id))

    get_string = get_text

    def get_texts(self, version_ids):

        """Return the texts of listed versions as a list of strings.

        Raises RevisionNotPresent if version is not present in

        file history.

        """

        return [''.join(self.get_lines(v)) for v in version_ids]

    def get_lines(self, version_id):

        """Return version contents as a sequence of lines.

        Raises RevisionNotPresent if version is not present in

        file history.

        """

        raise NotImplementedError(self.get_lines)

    def _get_lf_split_line_list(self, version_ids):

        return [StringIO(t).readlines() for t in self.get_texts(version_ids)]

    def get_ancestry(self, version_ids, topo_sorted=True):

        """Return a list of all ancestors of given version(s). This

        will not include the null revision.

        This list will not be topologically sorted if topo_sorted=False is

        passed.

        Must raise RevisionNotPresent if any of the given versions are

        not present in file history."""

        if isinstance(version_ids, basestring):

            version_ids = [version_ids]

        raise NotImplementedError(self.get_ancestry)

    def get_ancestry_with_ghosts(self, version_ids):

        """Return a list of all ancestors of given version(s). This

        will not include the null revision.

        Must raise RevisionNotPresent if any of the given versions are

        not present in file history.

        Ghosts that are known about will be included in ancestry list,

        but are not explicitly marked.

        """

        raise NotImplementedError(self.get_ancestry_with_ghosts)

    @deprecated_method(one_four)

    def get_graph(self, version_ids=None):

        """Return a graph from the versioned file. 

        Ghosts are not listed or referenced in the graph.

        :param version_ids: Versions to select.

                            None means retrieve all versions.

        """

        if version_ids is None:

            result = self.get_parent_map(self.versions())

        else:

            result = {}

            pending = set(version_ids)

            while pending:

                this_iteration = pending

                pending = set()

                parents = self.get_parent_map(this_iteration)

                for version, parents in parents.iteritems():

                    result[version] = parents

                    for parent in parents:

                        if parent in result:

                            continue

                        pending.add(parent)

        references = set()

        for parents in result.itervalues():

            references.update(parents)

        existing_parents = self.get_parent_map(references)

        for key, parents in result.iteritems():

            present_parents = [parent for parent in parents if parent in

                existing_parents]

            result[key] = tuple(present_parents)

        return result

    @deprecated_method(one_four)

    def get_graph_with_ghosts(self):

        """Return a graph for the entire versioned file.

        Ghosts are referenced in parents list but are not

        explicitly listed.

        """

        raise NotImplementedError(self.get_graph_with_ghosts)

    def get_parent_map(self, version_ids):

        """Get a map of the parents of version_ids.

        :param version_ids: The version ids to look up parents for.

        :return: A mapping from version id to parents.

        """

        raise NotImplementedError(self.get_parent_map)

    @deprecated_method(one_four)

    def get_parents(self, version_id):

        """Return version names for parents of a version.

        Must raise RevisionNotPresent if version is not present in

        file history.

        """

        try:

            all = self.get_parent_map([version_id])[version_id]

        except KeyError:

            raise errors.RevisionNotPresent(version_id, self)

        result = []

        parent_parents = self.get_parent_map(all)

        for version_id in all:

            if version_id in parent_parents:

                result.append(version_id)

        return result

    def get_parents_with_ghosts(self, version_id):

        """Return version names for parents of version_id.

        Will raise RevisionNotPresent if version_id is not present

        in the history.

        Ghosts that are known about will be included in the parent list,

        but are not explicitly marked.

        """

        try:

            return list(self.get_parent_map([version_id])[version_id])

        except KeyError:

            raise errors.RevisionNotPresent(version_id, self)

    @deprecated_method(one_four)

    def annotate_iter(self, version_id):

        """Yield list of (version-id, line) pairs for the specified

        version.

        Must raise RevisionNotPresent if the given version is

        not present in file history.

        """

        return iter(self.annotate(version_id))

    def annotate(self, version_id):

        """Return a list of (version-id, line) tuples for version_id.

        :raise RevisionNotPresent: If the given version is

        not present in file history.

        """

        raise NotImplementedError(self.annotate)

    def join(self, other, pb=None, msg=None, version_ids=None,

             ignore_missing=False):

        """Integrate versions from other into this versioned file.

        If version_ids is None all versions from other should be

        incorporated into this versioned file.

        Must raise RevisionNotPresent if any of the specified versions

        are not present in the other file's history unless ignore_missing

        is supplied in which case they are silently skipped.

        """

        self._check_write_ok()

        return InterVersionedFile.get(other, self).join(

            pb,

            msg,

            version_ids,

            ignore_missing)

    def iter_lines_added_or_present_in_versions(self, version_ids=None,

                                                pb=None):

        """Iterate over the lines in the versioned file from version_ids.

        This may return lines from other versions. Each item the returned

        iterator yields is a tuple of a line and a text version that that line

        is present in (not introduced in).

        Ordering of results is in whatever order is most suitable for the

        underlying storage format.

        If a progress bar is supplied, it may be used to indicate progress.

        The caller is responsible for cleaning up progress bars (because this

        is an iterator).

        NOTES: Lines are normalised: they will all have \n terminators.

               Lines are returned in arbitrary order.

        :return: An iterator over (line, version_id).

        """

        raise NotImplementedError(self.iter_lines_added_or_present_in_versions)

    @deprecated_method(one_four)

    def iter_parents(self, version_ids):

        """Iterate through the parents for many version ids.

        :param version_ids: An iterable yielding version_ids.

        :return: An iterator that yields (version_id, parents). Requested 

            version_ids not present in the versioned file are simply skipped.

            The order is undefined, allowing for different optimisations in

            the underlying implementation.

        """

        return self.get_parent_map(version_ids).iteritems()

    def plan_merge(self, ver_a, ver_b):

        """Return pseudo-annotation indicating how the two versions merge.

        This is computed between versions a and b and their common

        base.

        Weave lines present in none of them are skipped entirely.

        Legend:

        killed-base Dead in base revision

        killed-both Killed in each revision

        killed-a    Killed in a

        killed-b    Killed in b

        unchanged   Alive in both a and b (possibly created in both)

        new-a       Created in a

        new-b       Created in b

        ghost-a     Killed in a, unborn in b    

        ghost-b     Killed in b, unborn in a

        irrelevant  Not in either revision

        """

        raise NotImplementedError(VersionedFile.plan_merge)

    def weave_merge(self, plan, a_marker=TextMerge.A_MARKER,

                    b_marker=TextMerge.B_MARKER):

        return PlanWeaveMerge(plan, a_marker, b_marker).merge_lines()[0]

class _PlanMergeVersionedFile(object):

    """A VersionedFile for uncommitted and committed texts.

    It is intended to allow merges to be planned with working tree texts.

    It implements only the small part of the VersionedFile interface used by

    PlanMerge.  It falls back to multiple versionedfiles for data not stored in

    _PlanMergeVersionedFile itself.

    """

    def __init__(self, file_id, fallback_versionedfiles=None):

        """Constuctor

        :param file_id: Used when raising exceptions.

        :param fallback_versionedfiles: If supplied, the set of fallbacks to

            use.  Otherwise, _PlanMergeVersionedFile.fallback_versionedfiles

            can be appended to later.

        """

        self._file_id = file_id

        if fallback_versionedfiles is None:

            self.fallback_versionedfiles = []

        else:

            self.fallback_versionedfiles = fallback_versionedfiles

        self._parents = {}

        self._lines = {}

    def plan_merge(self, ver_a, ver_b, base=None):

        """See VersionedFile.plan_merge"""

        from bzrlib.merge import _PlanMerge

        if base is None:

            return _PlanMerge(ver_a, ver_b, self).plan_merge()

        old_plan = list(_PlanMerge(ver_a, base, self).plan_merge())

        new_plan = list(_PlanMerge(ver_a, ver_b, self).plan_merge())

        return _PlanMerge._subtract_plans(old_plan, new_plan)

    def plan_lca_merge(self, ver_a, ver_b, base=None):

        from bzrlib.merge import _PlanLCAMerge

        graph = self._get_graph()

        new_plan = _PlanLCAMerge(ver_a, ver_b, self, graph).plan_merge()

        if base is None:

            return new_plan

        old_plan = _PlanLCAMerge(ver_a, base, self, graph).plan_merge()

        return _PlanLCAMerge._subtract_plans(list(old_plan), list(new_plan))

    def add_lines(self, version_id, parents, lines):

        """See VersionedFile.add_lines

        Lines are added locally, not fallback versionedfiles.  Also, ghosts are

        permitted.  Only reserved ids are permitted.

        """

        if not revision.is_reserved_id(version_id):

            raise ValueError('Only reserved ids may be used')

        if parents is None:

            raise ValueError('Parents may not be None')

        if lines is None:

            raise ValueError('Lines may not be None')

        self._parents[version_id] = tuple(parents)

        self._lines[version_id] = lines

    def get_lines(self, version_id):

        """See VersionedFile.get_ancestry"""

        lines = self._lines.get(version_id)

        if lines is not None:

            return lines

        for versionedfile in self.fallback_versionedfiles:

            try:

                return versionedfile.get_lines(version_id)

            except errors.RevisionNotPresent:

                continue

        else:

            raise errors.RevisionNotPresent(version_id, self._file_id)

    def get_ancestry(self, version_id, topo_sorted=False):

        """See VersionedFile.get_ancestry.

        Note that this implementation assumes that if a VersionedFile can

        answer get_ancestry at all, it can give an authoritative answer.  In

        fact, ghosts can invalidate this assumption.  But it's good enough

        99% of the time, and far cheaper/simpler.

        Also note that the results of this version are never topologically

        sorted, and are a set.

        """

        if topo_sorted:

            raise ValueError('This implementation does not provide sorting')

        parents = self._parents.get(version_id)

        if parents is None:

            for vf in self.fallback_versionedfiles:

                try:

                    return vf.get_ancestry(version_id, topo_sorted=False)

                except errors.RevisionNotPresent:

                    continue

            else:

                raise errors.RevisionNotPresent(version_id, self._file_id)

        ancestry = set([version_id])

        for parent in parents:

            ancestry.update(self.get_ancestry(parent, topo_sorted=False))

        return ancestry

    def get_parent_map(self, version_ids):

        """See VersionedFile.get_parent_map"""

        result = {}

        pending = set(version_ids)

        for key in version_ids:

            try:

                result[key] = self._parents[key]

            except KeyError:

                pass

        pending = pending - set(result.keys())

        for versionedfile in self.fallback_versionedfiles:

            parents = versionedfile.get_parent_map(pending)

            result.update(parents)

            pending = pending - set(parents.keys())

            if not pending:

                return result

        return result

    def _get_graph(self):

        from bzrlib.graph import (

            DictParentsProvider,

            Graph,

            _StackedParentsProvider,

            )

        from bzrlib.repofmt.knitrepo import _KnitParentsProvider

        parent_providers = [DictParentsProvider(self._parents)]

        for vf in self.fallback_versionedfiles:

            parent_providers.append(_KnitParentsProvider(vf))

        return Graph(_StackedParentsProvider(parent_providers))

class PlanWeaveMerge(TextMerge):

    """Weave merge that takes a plan as its input.

    This exists so that VersionedFile.plan_merge is implementable.

    Most callers will want to use WeaveMerge instead.

    """

    def __init__(self, plan, a_marker=TextMerge.A_MARKER,

                 b_marker=TextMerge.B_MARKER):

        TextMerge.__init__(self, a_marker, b_marker)

        self.plan = plan

    def _merge_struct(self):

        lines_a = []

        lines_b = []

        ch_a = ch_b = False

        def outstanding_struct():

            if not lines_a and not lines_b:

                return

            elif ch_a and not ch_b:

                # one-sided change:

                yield(lines_a,)

            elif ch_b and not ch_a:

                yield (lines_b,)

            elif lines_a == lines_b:

                yield(lines_a,)

            else:

                yield (lines_a, lines_b)

        # We previously considered either 'unchanged' or 'killed-both' lines

        # to be possible places to resynchronize.  However, assuming agreement

        # on killed-both lines may be too aggressive. -- mbp 20060324

        for state, line in self.plan:

            if state == 'unchanged':

                # resync and flush queued conflicts changes if any

                for struct in outstanding_struct():

                    yield struct

                lines_a = []

                lines_b = []

                ch_a = ch_b = False

            if state == 'unchanged':

                if line:

                    yield ([line],)

            elif state == 'killed-a':

                ch_a = True

                lines_b.append(line)

            elif state == 'killed-b':

                ch_b = True

                lines_a.append(line)

            elif state == 'new-a':

                ch_a = True

                lines_a.append(line)

            elif state == 'new-b':

                ch_b = True

                lines_b.append(line)

            elif state == 'conflicted-a':

                ch_b = ch_a = True