~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

# Author: Martin Pool <mbp@canonical.com>

"""Weave - storage of related text file versions"""

# XXX: If we do weaves this way, will a merge still behave the same

# way if it's done in a different order?  That's a pretty desirable

# property.

# TODO: Nothing here so far assumes the lines are really \n newlines,

# rather than being split up in some other way.  We could accomodate

# binaries, perhaps by naively splitting on \n or perhaps using

# something like a rolling checksum.

# TODO: End marker for each version so we can stop reading?

# TODO: Check that no insertion occurs inside a deletion that was

# active in the version of the insertion.

# TODO: In addition to the SHA-1 check, perhaps have some code that

# checks structural constraints of the weave: ie that insertions are

# properly nested, that there is no text outside of an insertion, that

# insertions or deletions are not repeated, etc.

# TODO: Parallel-extract that passes back each line along with a

# description of which revisions include it.  Nice for checking all

# shas or calculating stats in parallel.

# TODO: Using a single _extract routine and then processing the output

# is probably inefficient.  It's simple enough that we can afford to

# have slight specializations for different ways its used: annotate,

# basis for add, get, etc.

# TODO: Probably the API should work only in names to hide the integer

# indexes from the user.

# TODO: Is there any potential performance win by having an add()

# variant that is passed a pre-cooked version of the single basis

# version?

# TODO: Reweave can possibly be made faster by remembering diffs

# where the basis and destination are unchanged.

# FIXME: Sometimes we will be given a parents list for a revision

# that includes some redundant parents (i.e. already a parent of 

# something in the list.)  We should eliminate them.  This can 

# be done fairly efficiently because the sequence numbers constrain

# the possible relationships.

# FIXME: the conflict markers should be *7* characters

from copy import copy

from cStringIO import StringIO

from difflib import SequenceMatcher

import os

import sha

import time

from bzrlib.trace import mutter

from bzrlib.errors import (WeaveError, WeaveFormatError, WeaveParentMismatch,

        RevisionAlreadyPresent,

        RevisionNotPresent,

        WeaveRevisionAlreadyPresent,

        WeaveRevisionNotPresent,

        )

import bzrlib.errors as errors

from bzrlib.osutils import sha_strings

from bzrlib.symbol_versioning import *

from bzrlib.tsort import topo_sort

from bzrlib.versionedfile import VersionedFile, InterVersionedFile

from bzrlib.weavefile import _read_weave_v5, write_weave_v5

class Weave(VersionedFile):

    """weave - versioned text file storage.

    A Weave 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 can be identified in either of two ways:

    * a nonnegative index number.

    * a version-id string.

    Typically the index number will be valid only inside this weave and

    the version-id is used to reference it in the larger world.

    The weave is represented as a list mixing edit instructions and

    literal text.  Each entry in _weave can be either a string (or

    unicode), or a tuple.  If a string, it means that the given line

    should be output in the currently active revisions.

    If a tuple, it gives a processing instruction saying in which

    revisions the enclosed lines are active.  The tuple has the form

    (instruction, version).

    The instruction can be '{' or '}' for an insertion block, and '['

    and ']' for a deletion block respectively.  The version is the

    integer version index.  There is no replace operator, only deletes

    and inserts.  For '}', the end of an insertion, there is no

    version parameter because it always closes the most recently

    opened insertion.

    Constraints/notes:

    * A later version can delete lines that were introduced by any

      number of ancestor versions; this implies that deletion

      instructions can span insertion blocks without regard to the

      insertion block's nesting.

    * Similarly, deletions need not be properly nested with regard to

      each other, because they might have been generated by

      independent revisions.

    * Insertions are always made by inserting a new bracketed block

      into a single point in the previous weave.  This implies they

      can nest but not overlap, and the nesting must always have later

      insertions on the inside.

    * It doesn't seem very useful to have an active insertion

      inside an inactive insertion, but it might happen.

    * Therefore, all instructions are always"considered"; that

      is passed onto and off the stack.  An outer inactive block

      doesn't disable an inner block.

    * Lines are enabled if the most recent enclosing insertion is

      active and none of the enclosing deletions are active.

    * There is no point having a deletion directly inside its own

      insertion; you might as well just not write it.  And there

      should be no way to get an earlier version deleting a later

      version.

    _weave

        Text of the weave; list of control instruction tuples and strings.

    _parents

        List of parents, indexed by version number.

        It is only necessary to store the minimal set of parents for

        each version; the parent's parents are implied.

    _sha1s

        List of hex SHA-1 of each version.

    _names

        List of symbolic names for each version.  Each should be unique.

    _name_map

        For each name, the version number.

    _weave_name

        Descriptive name of this weave; typically the filename if known.

        Set by read_weave.

    """

    __slots__ = ['_weave', '_parents', '_sha1s', '_names', '_name_map',

                 '_weave_name']

    def __init__(self, weave_name=None, access_mode='w'):

        super(Weave, self).__init__(access_mode)

        self._weave = []

        self._parents = []

        self._sha1s = []

        self._names = []

        self._name_map = {}

        self._weave_name = weave_name

    def __repr__(self):

        return "Weave(%r)" % self._weave_name

    def copy(self):

        """Return a deep copy of self.

        The copy can be modified without affecting the original weave."""

        other = Weave()

        other._weave = self._weave[:]

        other._parents = self._parents[:]

        other._sha1s = self._sha1s[:]

        other._names = self._names[:]

        other._name_map = self._name_map.copy()

        other._weave_name = self._weave_name

        return other

    def __eq__(self, other):

        if not isinstance(other, Weave):

            return False

        return self._parents == other._parents \

               and self._weave == other._weave \

               and self._sha1s == other._sha1s 

    def __ne__(self, other):

        return not self.__eq__(other)

    @deprecated_method(zero_eight)

    def idx_to_name(self, index):

        """Old public interface, the public interface is all names now."""

        return index

    def _idx_to_name(self, version):

        return self._names[version]

    @deprecated_method(zero_eight)

    def lookup(self, name):

        """Backwards compatability thunk:

        Return name, as name is valid in the api now, and spew deprecation

        warnings everywhere.

        """

        return name

    def _lookup(self, name):

        """Convert symbolic version name to index."""

        try:

            return self._name_map[name]

        except KeyError:

            raise RevisionNotPresent(name, self._weave_name)

    @deprecated_method(zero_eight)

    def iter_names(self):

        """Deprecated convenience function, please see VersionedFile.names()."""

        return iter(self.names())

    @deprecated_method(zero_eight)

    def names(self):

        """See Weave.versions for the current api."""

        return self.versions()

    def versions(self):

        """See VersionedFile.versions."""

        return self._names[:]

    def has_version(self, version_id):

        """See VersionedFile.has_version."""

        return self._name_map.has_key(version_id)

    __contains__ = has_version

    def get_delta(self, version_id):

        """See VersionedFile.get_delta."""

        return self.get_deltas([version_id])[version_id]

    def get_deltas(self, version_ids):

        """See VersionedFile.get_deltas."""

        version_ids = self.get_ancestry(version_ids)

        for version_id in version_ids:

            if not self.has_version(version_id):

                raise RevisionNotPresent(version_id, self)

        # try extracting all versions; parallel extraction is used

        nv = self.num_versions()

        sha1s = {}

        deltas = {}

        texts = {}

        inclusions = {}

        noeols = {}

        last_parent_lines = {}

        parents = {}

        parent_inclusions = {}

        parent_linenums = {}

        parent_noeols = {}

        current_hunks = {}

        diff_hunks = {}

        # its simplest to generate a full set of prepared variables.

        for i in range(nv):

            name = self._names[i]

            sha1s[name] = self.get_sha1(name)

            parents_list = self.get_parents(name)

            try:

                parent = parents_list[0]

                parents[name] = parent

                parent_inclusions[name] = inclusions[parent]

            except IndexError:

                parents[name] = None

                parent_inclusions[name] = set()

            # we want to emit start, finish, replacement_length, replacement_lines tuples.

            diff_hunks[name] = []

            current_hunks[name] = [0, 0, 0, []] # #start, finish, repl_length, repl_tuples

            parent_linenums[name] = 0

            noeols[name] = False

            parent_noeols[name] = False

            last_parent_lines[name] = None

            new_inc = set([name])

            for p in self._parents[i]:

                new_inc.update(inclusions[self._idx_to_name(p)])

            # debug only, known good so far.

            #assert set(new_inc) == set(self.get_ancestry(name)), \

            #    'failed %s != %s' % (set(new_inc), set(self.get_ancestry(name)))

            inclusions[name] = new_inc

        nlines = len(self._weave)

        for lineno, inserted, deletes, line in self._walk_internal():

            # a line is active in a version if:

            # insert is in the versions inclusions

            # and

            # deleteset & the versions inclusions is an empty set.

            # so - if we have a included by mapping - version is included by

            # children, we get a list of children to examine for deletes affect

            # ing them, which is less than the entire set of children.

            for version_id in version_ids:  

                # The active inclusion must be an ancestor,

                # and no ancestors must have deleted this line,

                # because we don't support resurrection.

                parent_inclusion = parent_inclusions[version_id]

                inclusion = inclusions[version_id]

                parent_active = inserted in parent_inclusion and not (deletes & parent_inclusion)

                version_active = inserted in inclusion and not (deletes & inclusion)

                if not parent_active and not version_active:

                    # unrelated line of ancestry

                    continue

                elif parent_active and version_active:

                    # shared line

                    parent_linenum = parent_linenums[version_id]

                    if current_hunks[version_id] != [parent_linenum, parent_linenum, 0, []]:

                        diff_hunks[version_id].append(tuple(current_hunks[version_id]))

                    parent_linenum += 1

                    current_hunks[version_id] = [parent_linenum, parent_linenum, 0, []]

                    parent_linenums[version_id] = parent_linenum

                    try:

                        if line[-1] != '\n':

                            noeols[version_id] = True

                    except IndexError:

                        pass

                elif parent_active and not version_active:

                    # deleted line

                    current_hunks[version_id][1] += 1

                    parent_linenums[version_id] += 1

                    last_parent_lines[version_id] = line

                elif not parent_active and version_active:

                    # replacement line

                    # noeol only occurs at the end of a file because we 

                    # diff linewise. We want to show noeol changes as a

                    # empty diff unless the actual eol-less content changed.

                    theline = line

                    try:

                        if last_parent_lines[version_id][-1] != '\n':

                            parent_noeols[version_id] = True

                    except (TypeError, IndexError):

                        pass

                    try:

                        if theline[-1] != '\n':

                            noeols[version_id] = True

                    except IndexError:

                        pass

                    new_line = False

                    parent_should_go = False

                    if parent_noeols[version_id] == noeols[version_id]:

                        # no noeol toggle, so trust the weaves statement

                        # that this line is changed.

                        new_line = True

                        if parent_noeols[version_id]:

                            theline = theline + '\n'

                    elif parent_noeols[version_id]:

                        # parent has no eol, we do:

                        # our line is new, report as such..

                        new_line = True

                    elif noeols[version_id]:

                        # append a eol so that it looks like

                        # a normalised delta

                        theline = theline + '\n'

                        if parents[version_id] is not None:

                        #if last_parent_lines[version_id] is not None:

                            parent_should_go = True

                        if last_parent_lines[version_id] != theline:

                            # but changed anyway

                            new_line = True

                            #parent_should_go = False

                    if new_line:

                        current_hunks[version_id][2] += 1

                        current_hunks[version_id][3].append((inserted, theline))

                    if parent_should_go:

                        # last hunk last parent line is not eaten

                        current_hunks[version_id][1] -= 1

                    if current_hunks[version_id][1] < 0:

                        current_hunks[version_id][1] = 0

                        # import pdb;pdb.set_trace()

                    # assert current_hunks[version_id][1] >= 0

        # flush last hunk

        for i in range(nv):

            version = self._idx_to_name(i)

            if current_hunks[version] != [0, 0, 0, []]:

                diff_hunks[version].append(tuple(current_hunks[version]))

        result = {}

        for version_id in version_ids:

            result[version_id] = (

                                  parents[version_id],

                                  sha1s[version_id],

                                  noeols[version_id],

                                  diff_hunks[version_id],

                                  )

        return result

    def get_parents(self, version_id):

        """See VersionedFile.get_parent."""

        return map(self._idx_to_name, self._parents[self._lookup(version_id)])

    def _check_repeated_add(self, name, parents, text, sha1):

        """Check that a duplicated add is OK.

        If it is, return the (old) index; otherwise raise an exception.

        """

        idx = self._lookup(name)

        if sorted(self._parents[idx]) != sorted(parents) \

            or sha1 != self._sha1s[idx]:

            raise RevisionAlreadyPresent(name, self._weave_name)

        return idx

    @deprecated_method(zero_eight)

    def add_identical(self, old_rev_id, new_rev_id, parents):

        """Please use Weave.clone_text now."""

        return self.clone_text(new_rev_id, old_rev_id, parents)

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

        """See VersionedFile.add_lines."""

        return self._add(version_id, lines, map(self._lookup, parents))

    @deprecated_method(zero_eight)

    def add(self, name, parents, text, sha1=None):

        """See VersionedFile.add_lines for the non deprecated api."""

        return self._add(name, text, map(self._maybe_lookup, parents), sha1)

    def _add(self, version_id, lines, parents, sha1=None):

        """Add a single text on top of the weave.

        Returns the index number of the newly added version.

        version_id

            Symbolic name for this version.

            (Typically the revision-id of the revision that added it.)

        parents

            List or set of direct parent version numbers.

        lines

            Sequence of lines to be added in the new version.

        """

        assert isinstance(version_id, basestring)

        if not sha1:

            sha1 = sha_strings(lines)

        if version_id in self._name_map:

            return self._check_repeated_add(version_id, parents, lines, sha1)

        self._check_versions(parents)

        ## self._check_lines(lines)

        new_version = len(self._parents)

        # if we abort after here the (in-memory) weave will be corrupt because only

        # some fields are updated

        # XXX: FIXME implement a succeed-or-fail of the rest of this routine.

        #      - Robert Collins 20060226

        self._parents.append(parents[:])

        self._sha1s.append(sha1)

        self._names.append(version_id)

        self._name_map[version_id] = new_version

        if not parents:

            # special case; adding with no parents revision; can do

            # this more quickly by just appending unconditionally.

            # even more specially, if we're adding an empty text we

            # need do nothing at all.

            if lines:

                self._weave.append(('{', new_version))

                self._weave.extend(lines)

                self._weave.append(('}', None))

            return new_version

        if len(parents) == 1:

            pv = list(parents)[0]

            if sha1 == self._sha1s[pv]:

                # special case: same as the single parent

                return new_version

        ancestors = self._inclusions(parents)

        l = self._weave

        # basis a list of (origin, lineno, line)

        basis_lineno = []

        basis_lines = []

        for origin, lineno, line in self._extract(ancestors):

            basis_lineno.append(lineno)

            basis_lines.append(line)

        # another small special case: a merge, producing the same text

        # as auto-merge

        if lines == basis_lines:

            return new_version            

        # add a sentinal, because we can also match against the final line

        basis_lineno.append(len(self._weave))

        # XXX: which line of the weave should we really consider

        # matches the end of the file?  the current code says it's the

        # last line of the weave?

        #print 'basis_lines:', basis_lines

        #print 'new_lines:  ', lines

        s = SequenceMatcher(None, basis_lines, lines)

        # offset gives the number of lines that have been inserted

        # into the weave up to the current point; if the original edit instruction

        # says to change line A then we actually change (A+offset)

        offset = 0

        for tag, i1, i2, j1, j2 in s.get_opcodes():

            # i1,i2 are given in offsets within basis_lines; we need to map them

            # back to offsets within the entire weave

            #print 'raw match', tag, i1, i2, j1, j2

            if tag == 'equal':

                continue

            i1 = basis_lineno[i1]

            i2 = basis_lineno[i2]

            assert 0 <= j1 <= j2 <= len(lines)

            #print tag, i1, i2, j1, j2

            # the deletion and insertion are handled separately.

            # first delete the region.

            if i1 != i2:

                self._weave.insert(i1+offset, ('[', new_version))

                self._weave.insert(i2+offset+1, (']', new_version))

                offset += 2

            if j1 != j2:

                # there may have been a deletion spanning up to

                # i2; we want to insert after this region to make sure

                # we don't destroy ourselves

                i = i2 + offset

                self._weave[i:i] = ([('{', new_version)] 

                                    + lines[j1:j2] 

                                    + [('}', None)])

                offset += 2 + (j2 - j1)

        return new_version

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

        """See VersionedFile.clone_text."""

        old_lines = self.get_text(old_version_id)

        self.add_lines(new_version_id, parents, old_lines)

    def _inclusions(self, versions):

        """Return set of all ancestors of given version(s)."""

        if not len(versions):

            return []

        i = set(versions)

        for v in xrange(max(versions), 0, -1):

            if v in i:

                # include all its parents

                i.update(self._parents[v])

        return i

        ## except IndexError:

        ##     raise ValueError("version %d not present in weave" % v)

    @deprecated_method(zero_eight)

    def inclusions(self, version_ids):

        """Deprecated - see VersionedFile.get_ancestry for the replacement."""

        if not version_ids:

            return []

        if isinstance(version_ids[0], int):

            return [self._idx_to_name(v) for v in self._inclusions(version_ids)]

        else:

            return self.get_ancestry(version_ids)

    def get_ancestry(self, version_ids):

        """See VersionedFile.get_ancestry."""

        if isinstance(version_ids, basestring):

            version_ids = [version_ids]

        i = self._inclusions([self._lookup(v) for v in version_ids])

        return [self._idx_to_name(v) for v in i]

    def _check_lines(self, text):

        if not isinstance(text, list):

            raise ValueError("text should be a list, not %s" % type(text))

        for l in text:

            if not isinstance(l, basestring):

                raise ValueError("text line should be a string or unicode, not %s"

                                 % type(l))

    def _check_versions(self, indexes):

        """Check everything in the sequence of indexes is valid"""

        for i in indexes:

            try:

                self._parents[i]

            except IndexError:

                raise IndexError("invalid version number %r" % i)

    def _compatible_parents(self, my_parents, other_parents):

        """During join check that other_parents are joinable with my_parents.

        Joinable is defined as 'is a subset of' - supersets may require 

        regeneration of diffs, but subsets do not.

        """

        return len(other_parents.difference(my_parents)) == 0

    def annotate(self, version_id):

        if isinstance(version_id, int):

            warn('Weave.annotate(int) is deprecated. Please use version names'

                 ' in all circumstances as of 0.8',

                 DeprecationWarning,

                 stacklevel=2

                 )

            result = []

            for origin, lineno, text in self._extract([version_id]):

                result.append((origin, text))

            return result

        else:

            return super(Weave, self).annotate(version_id)

    def annotate_iter(self, version_id):

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

        The index indicates when the line originated in the weave."""

        incls = [self._lookup(version_id)]

        for origin, lineno, text in self._extract(incls):

            yield self._idx_to_name(origin), text

    @deprecated_method(zero_eight)

    def _walk(self):

        """_walk has become visit, a supported api."""

        return self._walk_internal()

    def iter_lines_added_or_present_in_versions(self, version_ids=None):

        """See VersionedFile.iter_lines_added_or_present_in_versions()."""

        if version_ids is None:

            version_ids = self.versions()

        version_ids = set(version_ids)

        for lineno, inserted, deletes, line in self._walk_internal(version_ids):

            # if inserted not in version_ids then it was inserted before the

            # versions we care about, but because weaves cannot represent ghosts

            # properly, we do not filter down to that

            # if inserted not in version_ids: continue

            if line[-1] != '\n':

                yield line + '\n'

            else:

                yield line

    #@deprecated_method(zero_eight)

    def walk(self, version_ids=None):

        """See VersionedFile.walk."""

        return self._walk_internal(version_ids)

    def _walk_internal(self, version_ids=None):

        """Helper method for weave actions."""

        istack = []

        dset = set()

        lineno = 0         # line of weave, 0-based

        for l in self._weave:

            if l.__class__ == tuple:

                c, v = l

                isactive = None

                if c == '{':

                    istack.append(self._names[v])

                elif c == '}':

                    istack.pop()

                elif c == '[':

                    assert self._names[v] not in dset

                    dset.add(self._names[v])

                elif c == ']':

                    dset.remove(self._names[v])

                else:

                    raise WeaveFormatError('unexpected instruction %r' % v)

            else:

                assert l.__class__ in (str, unicode)

                assert istack

                yield lineno, istack[-1], frozenset(dset), l

            lineno += 1

        if istack:

            raise WeaveFormatError("unclosed insertion blocks "

                    "at end of weave: %s" % istack)

        if dset:

            raise WeaveFormatError("unclosed deletion blocks at end of weave: %s"

                                   % dset)

    def _extract(self, versions):

        """Yield annotation of lines in included set.

        Yields a sequence of tuples (origin, lineno, text), where

        origin is the origin version, lineno the index in the weave,

        and text the text of the line.