/brz/remove-bazaar

# Copyright (C) 2009 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Functionality for doing annotations in the 'optimal' way"""

from bzrlib import (

    errors,

    graph as _mod_graph,

    osutils,

    patiencediff,

    ui,

    )

class AnnotatorPolicy(object):

    """Variables that define annotations."""

class Annotator(object):

    """Class that drives performing annotations."""

    def __init__(self, vf):

        """Create a new Annotator from a VersionedFile."""

        self._vf = vf

        self._parent_map = {}

        self._text_cache = {}

        # Map from key => number of nexts that will be built from this key

        self._num_needed_children = {}

        self._annotations_cache = {}

        self._heads_provider = None

    def _update_needed_children(self, key, parent_keys):

        for parent_key in parent_keys:

            if parent_key in self._num_needed_children:

                self._num_needed_children[parent_key] += 1

            else:

                self._num_needed_children[parent_key] = 1

    def _get_needed_keys(self, key):

        """Determine the texts we need to get from the backing vf.

        :return: (vf_keys_needed, ann_keys_needed)

            vf_keys_needed  These are keys that we need to get from the vf

            ann_keys_needed Texts which we have in self._text_cache but we

                            don't have annotations for. We need to yield these

                            in the proper order so that we can get proper

                            annotations.

        """

        parent_map = self._parent_map

        # We need 1 extra copy of the node we will be looking at when we are

        # done

        self._num_needed_children[key] = 1

        vf_keys_needed = set()

        ann_keys_needed = set()

        needed_keys = set([key])

        while needed_keys:

            parent_lookup = []

            next_parent_map = {}

            for key in needed_keys:

                if key in self._parent_map:

                    # We don't need to lookup this key in the vf

                    if key not in self._text_cache:

                        # Extract this text from the vf

                        vf_keys_needed.add(key)

                    elif key not in self._annotations_cache:

                        # We do need to annotate

                        ann_keys_needed.add(key)

                        next_parent_map[key] = self._parent_map[key]

                else:

                    parent_lookup.append(key)

                    vf_keys_needed.add(key)

            needed_keys = set()

            next_parent_map.update(self._vf.get_parent_map(parent_lookup))

            for key, parent_keys in next_parent_map.iteritems():

                self._update_needed_children(key, parent_keys)

                needed_keys.update([key for key in parent_keys

                                         if key not in parent_map])

            parent_map.update(next_parent_map)

            # _heads_provider does some graph caching, so it is only valid while

            # self._parent_map hasn't changed

            self._heads_provider = None

        return vf_keys_needed, ann_keys_needed

    def _get_needed_texts(self, key, pb=None):

        """Get the texts we need to properly annotate key.

        :param key: A Key that is present in self._vf

        :return: Yield (this_key, text, num_lines)

            'text' is an opaque object that just has to work with whatever

            matcher object we are using. Currently it is always 'lines' but

            future improvements may change this to a simple text string.

        """

        keys, ann_keys = self._get_needed_keys(key)

        if pb is not None:

            pb.update('getting stream', 0, len(keys))

        stream  = self._vf.get_record_stream(keys, 'topological', True)

        for idx, record in enumerate(stream):

            if pb is not None:

                pb.update('extracting', 0, len(keys))

            if record.storage_kind == 'absent':

                raise errors.RevisionNotPresent(record.key, self._vf)

            this_key = record.key

            lines = osutils.chunks_to_lines(record.get_bytes_as('chunked'))

            num_lines = len(lines)

            self._text_cache[this_key] = lines

            yield this_key, lines, num_lines

        for key in ann_keys:

            lines = self._text_cache[key]

            num_lines = len(lines)

            yield key, lines, num_lines

    def _get_parent_annotations_and_matches(self, key, text, parent_key):

        """Get the list of annotations for the parent, and the matching lines.

        :param text: The opaque value given by _get_needed_texts

        :param parent_key: The key for the parent text

        :return: (parent_annotations, matching_blocks)

            parent_annotations is a list as long as the number of lines in

                parent

            matching_blocks is a list of (parent_idx, text_idx, len) tuples

                indicating which lines match between the two texts

        """

        parent_lines = self._text_cache[parent_key]

        parent_annotations = self._annotations_cache[parent_key]

        # PatienceSequenceMatcher should probably be part of Policy

        matcher = patiencediff.PatienceSequenceMatcher(None,

            parent_lines, text)

        matching_blocks = matcher.get_matching_blocks()

        return parent_annotations, matching_blocks

    def _update_from_one_parent(self, key, annotations, lines, parent_key):

        """Reannotate this text relative to its first parent."""

        parent_annotations, matching_blocks = self._get_parent_annotations_and_matches(

            key, lines, parent_key)

        for parent_idx, lines_idx, match_len in matching_blocks:

            # For all matching regions we copy across the parent annotations

            annotations[lines_idx:lines_idx + match_len] = \

                parent_annotations[parent_idx:parent_idx + match_len]

    def _update_from_other_parents(self, key, annotations, lines,

                                   this_annotation, parent_key):

        """Reannotate this text relative to a second (or more) parent."""

        parent_annotations, matching_blocks = self._get_parent_annotations_and_matches(

            key, lines, parent_key)

        last_ann = None

        last_parent = None

        last_res = None

        # TODO: consider making all annotations unique and then using 'is'

        #       everywhere. Current results claim that isn't any faster,

        #       because of the time spent deduping

        #       deduping also saves a bit of memory. For NEWS it saves ~1MB,

        #       but that is out of 200-300MB for extracting everything, so a

        #       fairly trivial amount

        for parent_idx, lines_idx, match_len in matching_blocks:

            # For lines which match this parent, we will now resolve whether

            # this parent wins over the current annotation

            ann_sub = annotations[lines_idx:lines_idx + match_len]

            par_sub = parent_annotations[parent_idx:parent_idx + match_len]

            if ann_sub == par_sub:

                continue

            for idx in xrange(match_len):

                ann = ann_sub[idx]

                par_ann = par_sub[idx]

                ann_idx = lines_idx + idx

                if ann == par_ann:

                    # Nothing to change

                    continue

                if ann == this_annotation:

                    # Originally claimed 'this', but it was really in this

                    # parent

                    annotations[ann_idx] = par_ann

                    continue

                # Resolve the fact that both sides have a different value for

                # last modified

                if ann == last_ann and par_ann == last_parent:

                    annotations[ann_idx] = last_res

                else:

                    new_ann = set(ann)

                    new_ann.update(par_ann)

                    new_ann = tuple(sorted(new_ann))

                    annotations[ann_idx] = new_ann

                    last_ann = ann

                    last_parent = par_ann

                    last_res = new_ann

    def _record_annotation(self, key, parent_keys, annotations):

        self._annotations_cache[key] = annotations

        for parent_key in parent_keys:

            num = self._num_needed_children[parent_key]

            num -= 1

            if num == 0:

                del self._text_cache[parent_key]

                del self._annotations_cache[parent_key]

                # Do we want to clean up _num_needed_children at this point as

                # well?

            self._num_needed_children[parent_key] = num

    def _annotate_one(self, key, text, num_lines):

        this_annotation = (key,)

        # Note: annotations will be mutated by calls to _update_from*

        annotations = [this_annotation] * num_lines

        parent_keys = self._parent_map[key]

        if parent_keys:

            self._update_from_one_parent(key, annotations, text, parent_keys[0])

            for parent in parent_keys[1:]:

                self._update_from_other_parents(key, annotations, text,

                                                this_annotation, parent)

        self._record_annotation(key, parent_keys, annotations)

    def add_special_text(self, key, parent_keys, text):

        """Add a specific text to the graph."""

        self._parent_map[key] = parent_keys

        self._text_cache[key] = osutils.split_lines(text)

        self._heads_provider = None

    def annotate(self, key):

        """Return annotated fulltext for the given key."""

        pb = ui.ui_factory.nested_progress_bar()

        try:

            for text_key, text, num_lines in self._get_needed_texts(key, pb=pb):

                self._annotate_one(text_key, text, num_lines)

        finally:

            pb.finished()

        try:

            annotations = self._annotations_cache[key]

        except KeyError:

            raise errors.RevisionNotPresent(key, self._vf)

        return annotations, self._text_cache[key]

    def _get_heads_provider(self):

        if self._heads_provider is None:

            self._heads_provider = _mod_graph.KnownGraph(self._parent_map)

        return self._heads_provider

    def annotate_flat(self, key):

        """Determine the single-best-revision to source for each line.

        This is meant as a compatibility thunk to how annotate() used to work.

        """

        annotations, lines = self.annotate(key)

        assert len(annotations) == len(lines)

        out = []

        heads = self._get_heads_provider().heads

        append = out.append

        for annotation, line in zip(annotations, lines):

            if len(annotation) == 1:

                append((annotation[0], line))

            else:

                the_heads = heads(annotation)

                if len(the_heads) == 1:

                    for head in the_heads:

                        break

                else:

                    # We need to resolve the ambiguity, for now just pick the

                    # sorted smallest

                    head = sorted(the_heads)[0]

                append((head, line))

        return out