# Copyright (C) 2005, 2006 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


import os
import errno
from tempfile import mkdtemp
import warnings

from bzrlib.branch import Branch
from bzrlib.conflicts import ConflictList, Conflict
from bzrlib.errors import (BzrCommandError,
                           BzrError,
                           NoCommonAncestor,
                           NoCommits,
                           NoSuchRevision,
                           NoSuchFile,
                           NotBranchError,
                           NotVersionedError,
                           UnrelatedBranches,
                           UnsupportedOperation,
                           WorkingTreeNotRevision,
                           BinaryFile,
                           )
from bzrlib.merge3 import Merge3
import bzrlib.osutils
from bzrlib.osutils import rename, pathjoin, rmtree
from progress import DummyProgress, ProgressPhase
from bzrlib.revision import common_ancestor, is_ancestor, NULL_REVISION
from bzrlib.textfile import check_text_lines
from bzrlib.trace import mutter, warning, note
from bzrlib.transform import (TreeTransform, resolve_conflicts, cook_conflicts,
                              FinalPaths, create_by_entry, unique_add)
from bzrlib.versionedfile import WeaveMerge
from bzrlib import ui

# TODO: Report back as changes are merged in

def _get_tree(treespec, local_branch=None):
    from bzrlib import workingtree
    location, revno = treespec
    if revno is None:
        tree = workingtree.WorkingTree.open_containing(location)[0]
        return tree.branch, tree
    branch = Branch.open_containing(location)[0]
    if revno == -1:
        revision = branch.last_revision()
    else:
        revision = branch.get_rev_id(revno)
        if revision is None:
            revision = NULL_REVISION
    return branch, _get_revid_tree(branch, revision, local_branch)


def _get_revid_tree(branch, revision, local_branch):
    if revision is None:
        base_tree = branch.bzrdir.open_workingtree()
    else:
        if local_branch is not None:
            if local_branch.base != branch.base:
                local_branch.fetch(branch, revision)
            base_tree = local_branch.repository.revision_tree(revision)
        else:
            base_tree = branch.repository.revision_tree(revision)
    return base_tree


def transform_tree(from_tree, to_tree, interesting_ids=None):
    merge_inner(from_tree.branch, to_tree, from_tree, ignore_zero=True,
                interesting_ids=interesting_ids, this_tree=from_tree)


class Merger(object):
    def __init__(self, this_branch, other_tree=None, base_tree=None, 
                 this_tree=None, pb=DummyProgress()):
        object.__init__(self)
        assert this_tree is not None, "this_tree is required"
        self.this_branch = this_branch
        self.this_basis = this_branch.last_revision()
        self.this_rev_id = None
        self.this_tree = this_tree
        self.this_revision_tree = None
        self.this_basis_tree = None
        self.other_tree = other_tree
        self.base_tree = base_tree
        self.ignore_zero = False
        self.backup_files = False
        self.interesting_ids = None
        self.show_base = False
        self.reprocess = False
        self._pb = pb 
        self.pp = None


    def revision_tree(self, revision_id):
        return self.this_branch.repository.revision_tree(revision_id)

    def ensure_revision_trees(self):
        if self.this_revision_tree is None:
            self.this_basis_tree = self.this_branch.repository.revision_tree(
                self.this_basis)
            if self.this_basis == self.this_rev_id:
                self.this_revision_tree = self.this_basis_tree

        if self.other_rev_id is None:
            other_basis_tree = self.revision_tree(self.other_basis)
            changes = other_basis_tree.changes_from(self.other_tree)
            if changes.has_changed():
                raise WorkingTreeNotRevision(self.this_tree)
            other_rev_id = self.other_basis
            self.other_tree = other_basis_tree

    def file_revisions(self, file_id):
        self.ensure_revision_trees()
        def get_id(tree, file_id):
            revision_id = tree.inventory[file_id].revision
            assert revision_id is not None
            return revision_id
        if self.this_rev_id is None:
            if self.this_basis_tree.get_file_sha1(file_id) != \
                self.this_tree.get_file_sha1(file_id):
                raise WorkingTreeNotRevision(self.this_tree)

        trees = (self.this_basis_tree, self.other_tree)
        return [get_id(tree, file_id) for tree in trees]

    def check_basis(self, check_clean, require_commits=True):
        if self.this_basis is None and require_commits is True:
            raise BzrCommandError("This branch has no commits")
        if check_clean:
            self.compare_basis()
            if self.this_basis != self.this_rev_id:
                raise BzrCommandError("Working tree has uncommitted changes.")

    def compare_basis(self):
        changes = self.this_tree.changes_from(self.this_tree.basis_tree())
        if not changes.has_changed():
            self.this_rev_id = self.this_basis

    def set_interesting_files(self, file_list):
        try:
            self._set_interesting_files(file_list)
        except NotVersionedError, e:
            raise BzrCommandError("%s is not a source file in any"
                                      " tree." % e.path)

    def _set_interesting_files(self, file_list):
        """Set the list of interesting ids from a list of files."""
        if file_list is None:
            self.interesting_ids = None
            return

        interesting_ids = set()
        for path in file_list:
            found_id = False
            for tree in (self.this_tree, self.base_tree, self.other_tree):
                file_id = tree.inventory.path2id(path)
                if file_id is not None:
                    interesting_ids.add(file_id)
                    found_id = True
            if not found_id:
                raise NotVersionedError(path=path)
        self.interesting_ids = interesting_ids

    def set_pending(self):
        if not self.base_is_ancestor:
            return
        if self.other_rev_id is None:
            return
        ancestry = self.this_branch.repository.get_ancestry(self.this_basis)
        if self.other_rev_id in ancestry:
            return
        self.this_tree.add_parent_tree((self.other_rev_id, self.other_tree))

    def set_other(self, other_revision):
        """Set the revision and tree to merge from.

        This sets the other_tree, other_rev_id, other_basis attributes.

        :param other_revision: The [path, revision] list to merge from.
        """
        other_branch, self.other_tree = _get_tree(other_revision,
                                                  self.this_branch)
        if other_revision[1] == -1:
            self.other_rev_id = other_branch.last_revision()
            if self.other_rev_id is None:
                raise NoCommits(other_branch)
            self.other_basis = self.other_rev_id
        elif other_revision[1] is not None:
            self.other_rev_id = other_branch.get_rev_id(other_revision[1])
            self.other_basis = self.other_rev_id
        else:
            self.other_rev_id = None
            self.other_basis = other_branch.last_revision()
            if self.other_basis is None:
                raise NoCommits(other_branch)
        if other_branch.base != self.this_branch.base:
            self.this_branch.fetch(other_branch, last_revision=self.other_basis)

    def find_base(self):
        self.set_base([None, None])

    def set_base(self, base_revision):
        """Set the base revision to use for the merge.

        :param base_revision: A 2-list containing a path and revision number.
        """
        mutter("doing merge() with no base_revision specified")
        if base_revision == [None, None]:
            try:
                pb = bzrlib.ui.ui_factory.nested_progress_bar()
                try:
                    this_repo = self.this_branch.repository
                    self.base_rev_id = common_ancestor(self.this_basis, 
                                                       self.other_basis, 
                                                       this_repo, pb)
                finally:
                    pb.finished()
            except NoCommonAncestor:
                raise UnrelatedBranches()
            self.base_tree = _get_revid_tree(self.this_branch, self.base_rev_id,
                                            None)
            self.base_is_ancestor = True
        else:
            base_branch, self.base_tree = _get_tree(base_revision)
            if base_revision[1] == -1:
                self.base_rev_id = base_branch.last_revision()
            elif base_revision[1] is None:
                self.base_rev_id = None
            else:
                self.base_rev_id = base_branch.get_rev_id(base_revision[1])
            if self.this_branch.base != base_branch.base:
                self.this_branch.fetch(base_branch)
            self.base_is_ancestor = is_ancestor(self.this_basis, 
                                                self.base_rev_id,
                                                self.this_branch)

    def do_merge(self):
        kwargs = {'working_tree':self.this_tree, 'this_tree': self.this_tree, 
                  'other_tree': self.other_tree, 
                  'interesting_ids': self.interesting_ids,
                  'pp': self.pp}
        if self.merge_type.requires_base:
            kwargs['base_tree'] = self.base_tree
        if self.merge_type.supports_reprocess:
            kwargs['reprocess'] = self.reprocess
        elif self.reprocess:
            raise BzrError("Conflict reduction is not supported for merge"
                                  " type %s." % self.merge_type)
        if self.merge_type.supports_show_base:
            kwargs['show_base'] = self.show_base
        elif self.show_base:
            raise BzrError("Showing base is not supported for this"
                                  " merge type. %s" % self.merge_type)
        merge = self.merge_type(pb=self._pb, **kwargs)
        if len(merge.cooked_conflicts) == 0:
            if not self.ignore_zero:
                note("All changes applied successfully.")
        else:
            note("%d conflicts encountered." % len(merge.cooked_conflicts))

        return len(merge.cooked_conflicts)

    def regen_inventory(self, new_entries):
        old_entries = self.this_tree.read_working_inventory()
        new_inventory = {}
        by_path = {}
        new_entries_map = {} 
        for path, file_id in new_entries:
            if path is None:
                continue
            new_entries_map[file_id] = path

        def id2path(file_id):
            path = new_entries_map.get(file_id)
            if path is not None:
                return path
            entry = old_entries[file_id]
            if entry.parent_id is None:
                return entry.name
            return pathjoin(id2path(entry.parent_id), entry.name)
            
        for file_id in old_entries:
            entry = old_entries[file_id]
            path = id2path(file_id)
            if file_id in self.base_tree.inventory:
                executable = getattr(self.base_tree.inventory[file_id], 'executable', False)
            else:
                executable = getattr(entry, 'executable', False)
            new_inventory[file_id] = (path, file_id, entry.parent_id, 
                                      entry.kind, executable)
                                      
            by_path[path] = file_id
        
        deletions = 0
        insertions = 0
        new_path_list = []
        for path, file_id in new_entries:
            if path is None:
                del new_inventory[file_id]
                deletions += 1
            else:
                new_path_list.append((path, file_id))
                if file_id not in old_entries:
                    insertions += 1
        # Ensure no file is added before its parent
        new_path_list.sort()
        for path, file_id in new_path_list:
            if path == '':
                parent = None
            else:
                parent = by_path[os.path.dirname(path)]
            abspath = pathjoin(self.this_tree.basedir, path)
            kind = bzrlib.osutils.file_kind(abspath)
            if file_id in self.base_tree.inventory:
                executable = getattr(self.base_tree.inventory[file_id], 'executable', False)
            else:
                executable = False
            new_inventory[file_id] = (path, file_id, parent, kind, executable)
            by_path[path] = file_id 

        # Get a list in insertion order
        new_inventory_list = new_inventory.values()
        mutter ("""Inventory regeneration:
    old length: %i insertions: %i deletions: %i new_length: %i"""\
            % (len(old_entries), insertions, deletions, 
               len(new_inventory_list)))
        assert len(new_inventory_list) == len(old_entries) + insertions\
            - deletions
        new_inventory_list.sort()
        return new_inventory_list


class Merge3Merger(object):
    """Three-way merger that uses the merge3 text merger"""
    requires_base = True
    supports_reprocess = True
    supports_show_base = True
    history_based = False

    def __init__(self, working_tree, this_tree, base_tree, other_tree, 
                 interesting_ids=None, reprocess=False, show_base=False,
                 pb=DummyProgress(), pp=None):
        """Initialize the merger object and perform the merge."""
        object.__init__(self)
        self.this_tree = working_tree
        self.base_tree = base_tree
        self.other_tree = other_tree
        self._raw_conflicts = []
        self.cooked_conflicts = []
        self.reprocess = reprocess
        self.show_base = show_base
        self.pb = pb
        self.pp = pp
        if self.pp is None:
            self.pp = ProgressPhase("Merge phase", 3, self.pb)

        if interesting_ids is not None:
            all_ids = interesting_ids
        else:
            all_ids = set(base_tree)
            all_ids.update(other_tree)
        working_tree.lock_write()
        self.tt = TreeTransform(working_tree, self.pb)
        try:
            self.pp.next_phase()
            child_pb = ui.ui_factory.nested_progress_bar()
            try:
                for num, file_id in enumerate(all_ids):
                    child_pb.update('Preparing file merge', num, len(all_ids))
                    self.merge_names(file_id)
                    file_status = self.merge_contents(file_id)
                    self.merge_executable(file_id, file_status)
            finally:
                child_pb.finished()
                
            self.pp.next_phase()
            child_pb = ui.ui_factory.nested_progress_bar()
            try:
                fs_conflicts = resolve_conflicts(self.tt, child_pb)
            finally:
                child_pb.finished()
            self.cook_conflicts(fs_conflicts)
            for conflict in self.cooked_conflicts:
                warning(conflict)
            self.pp.next_phase()
            results = self.tt.apply()
            self.write_modified(results)
            try:
                working_tree.add_conflicts(self.cooked_conflicts)
            except UnsupportedOperation:
                pass
        finally:
            self.tt.finalize()
            working_tree.unlock()
            self.pb.clear()

    def write_modified(self, results):
        modified_hashes = {}
        for path in results.modified_paths:
            file_id = self.this_tree.path2id(self.this_tree.relpath(path))
            if file_id is None:
                continue
            hash = self.this_tree.get_file_sha1(file_id)
            if hash is None:
                continue
            modified_hashes[file_id] = hash
        self.this_tree.set_merge_modified(modified_hashes)

    @staticmethod
    def parent(entry, file_id):
        """Determine the parent for a file_id (used as a key method)"""
        if entry is None:
            return None
        return entry.parent_id

    @staticmethod
    def name(entry, file_id):
        """Determine the name for a file_id (used as a key method)"""
        if entry is None:
            return None
        return entry.name
    
    @staticmethod
    def contents_sha1(tree, file_id):
        """Determine the sha1 of the file contents (used as a key method)."""
        if file_id not in tree:
            return None
        return tree.get_file_sha1(file_id)

    @staticmethod
    def executable(tree, file_id):
        """Determine the executability of a file-id (used as a key method)."""
        if file_id not in tree:
            return None
        if tree.kind(file_id) != "file":
            return False
        return tree.is_executable(file_id)

    @staticmethod
    def kind(tree, file_id):
        """Determine the kind of a file-id (used as a key method)."""
        if file_id not in tree:
            return None
        return tree.kind(file_id)

    @staticmethod
    def scalar_three_way(this_tree, base_tree, other_tree, file_id, key):
        """Do a three-way test on a scalar.
        Return "this", "other" or "conflict", depending whether a value wins.
        """
        key_base = key(base_tree, file_id)
        key_other = key(other_tree, file_id)
        #if base == other, either they all agree, or only THIS has changed.
        if key_base == key_other:
            return "this"
        key_this = key(this_tree, file_id)
        if key_this not in (key_base, key_other):
            return "conflict"
        # "Ambiguous clean merge"
        elif key_this == key_other:
            return "this"
        else:
            assert key_this == key_base
            return "other"

    def merge_names(self, file_id):
        """Perform a merge on file_id names and parents"""
        def get_entry(tree):
            if file_id in tree.inventory:
                return tree.inventory[file_id]
            else:
                return None
        this_entry = get_entry(self.this_tree)
        other_entry = get_entry(self.other_tree)
        base_entry = get_entry(self.base_tree)
        name_winner = self.scalar_three_way(this_entry, base_entry, 
                                            other_entry, file_id, self.name)
        parent_id_winner = self.scalar_three_way(this_entry, base_entry, 
                                                 other_entry, file_id, 
                                                 self.parent)
        if this_entry is None:
            if name_winner == "this":
                name_winner = "other"
            if parent_id_winner == "this":
                parent_id_winner = "other"
        if name_winner == "this" and parent_id_winner == "this":
            return
        if name_winner == "conflict":
            trans_id = self.tt.trans_id_file_id(file_id)
            self._raw_conflicts.append(('name conflict', trans_id, 
                                        self.name(this_entry, file_id), 
                                        self.name(other_entry, file_id)))
        if parent_id_winner == "conflict":
            trans_id = self.tt.trans_id_file_id(file_id)
            self._raw_conflicts.append(('parent conflict', trans_id, 
                                        self.parent(this_entry, file_id), 
                                        self.parent(other_entry, file_id)))
        if other_entry is None:
            # it doesn't matter whether the result was 'other' or 
            # 'conflict'-- if there's no 'other', we leave it alone.
            return
        # if we get here, name_winner and parent_winner are set to safe values.
        winner_entry = {"this": this_entry, "other": other_entry, 
                        "conflict": other_entry}
        trans_id = self.tt.trans_id_file_id(file_id)
        parent_id = winner_entry[parent_id_winner].parent_id
        parent_trans_id = self.tt.trans_id_file_id(parent_id)
        self.tt.adjust_path(winner_entry[name_winner].name, parent_trans_id,
                            trans_id)

    def merge_contents(self, file_id):
        """Performa a merge on file_id contents."""
        def contents_pair(tree):
            if file_id not in tree:
                return (None, None)
            kind = tree.kind(file_id)
            if kind == "file":
                contents = tree.get_file_sha1(file_id)
            elif kind == "symlink":
                contents = tree.get_symlink_target(file_id)
            else:
                contents = None
            return kind, contents

        def contents_conflict():
            trans_id = self.tt.trans_id_file_id(file_id)
            name = self.tt.final_name(trans_id)
            parent_id = self.tt.final_parent(trans_id)
            if file_id in self.this_tree.inventory:
                self.tt.unversion_file(trans_id)
                self.tt.delete_contents(trans_id)
            file_group = self._dump_conflicts(name, parent_id, file_id, 
                                              set_version=True)
            self._raw_conflicts.append(('contents conflict', file_group))

        # See SPOT run.  run, SPOT, run.
        # So we're not QUITE repeating ourselves; we do tricky things with
        # file kind...
        base_pair = contents_pair(self.base_tree)
        other_pair = contents_pair(self.other_tree)
        if base_pair == other_pair:
            # OTHER introduced no changes
            return "unmodified"
        this_pair = contents_pair(self.this_tree)
        if this_pair == other_pair:
            # THIS and OTHER introduced the same changes
            return "unmodified"
        else:
            trans_id = self.tt.trans_id_file_id(file_id)
            if this_pair == base_pair:
                # only OTHER introduced changes
                if file_id in self.this_tree:
                    # Remove any existing contents
                    self.tt.delete_contents(trans_id)
                if file_id in self.other_tree:
                    # OTHER changed the file
                    create_by_entry(self.tt, 
                                    self.other_tree.inventory[file_id], 
                                    self.other_tree, trans_id)
                    if file_id not in self.this_tree.inventory:
                        self.tt.version_file(file_id, trans_id)
                    return "modified"
                elif file_id in self.this_tree.inventory:
                    # OTHER deleted the file
                    self.tt.unversion_file(trans_id)
                    return "deleted"
            #BOTH THIS and OTHER introduced changes; scalar conflict
            elif this_pair[0] == "file" and other_pair[0] == "file":
                # THIS and OTHER are both files, so text merge.  Either
                # BASE is a file, or both converted to files, so at least we
                # have agreement that output should be a file.
                try:
                    self.text_merge(file_id, trans_id)
                except BinaryFile:
                    return contents_conflict()
                if file_id not in self.this_tree.inventory:
                    self.tt.version_file(file_id, trans_id)
                try:
                    self.tt.tree_kind(trans_id)
                    self.tt.delete_contents(trans_id)
                except NoSuchFile:
                    pass
                return "modified"
            else:
                # Scalar conflict, can't text merge.  Dump conflicts
                return contents_conflict()

    def get_lines(self, tree, file_id):
        """Return the lines in a file, or an empty list."""
        if file_id in tree:
            return tree.get_file(file_id).readlines()
        else:
            return []

    def text_merge(self, file_id, trans_id):
        """Perform a three-way text merge on a file_id"""
        # it's possible that we got here with base as a different type.
        # if so, we just want two-way text conflicts.
        if file_id in self.base_tree and \
            self.base_tree.kind(file_id) == "file":
            base_lines = self.get_lines(self.base_tree, file_id)
        else:
            base_lines = []
        other_lines = self.get_lines(self.other_tree, file_id)
        this_lines = self.get_lines(self.this_tree, file_id)
        m3 = Merge3(base_lines, this_lines, other_lines)
        start_marker = "!START OF MERGE CONFLICT!" + "I HOPE THIS IS UNIQUE"
        if self.show_base is True:
            base_marker = '|' * 7
        else:
            base_marker = None

        def iter_merge3(retval):
            retval["text_conflicts"] = False
            for line in m3.merge_lines(name_a = "TREE", 
                                       name_b = "MERGE-SOURCE", 
                                       name_base = "BASE-REVISION",
                                       start_marker=start_marker, 
                                       base_marker=base_marker,
                                       reprocess=self.reprocess):
                if line.startswith(start_marker):
                    retval["text_conflicts"] = True
                    yield line.replace(start_marker, '<' * 7)
                else:
                    yield line
        retval = {}
        merge3_iterator = iter_merge3(retval)
        self.tt.create_file(merge3_iterator, trans_id)
        if retval["text_conflicts"] is True:
            self._raw_conflicts.append(('text conflict', trans_id))
            name = self.tt.final_name(trans_id)
            parent_id = self.tt.final_parent(trans_id)
            file_group = self._dump_conflicts(name, parent_id, file_id, 
                                              this_lines, base_lines,
                                              other_lines)
            file_group.append(trans_id)

    def _dump_conflicts(self, name, parent_id, file_id, this_lines=None, 
                        base_lines=None, other_lines=None, set_version=False,
                        no_base=False):
        """Emit conflict files.
        If this_lines, base_lines, or other_lines are omitted, they will be
        determined automatically.  If set_version is true, the .OTHER, .THIS
        or .BASE (in that order) will be created as versioned files.
        """
        data = [('OTHER', self.other_tree, other_lines), 
                ('THIS', self.this_tree, this_lines)]
        if not no_base:
            data.append(('BASE', self.base_tree, base_lines))
        versioned = False
        file_group = []
        for suffix, tree, lines in data:
            if file_id in tree:
                trans_id = self._conflict_file(name, parent_id, tree, file_id,
                                               suffix, lines)
                file_group.append(trans_id)
                if set_version and not versioned:
                    self.tt.version_file(file_id, trans_id)
                    versioned = True
        return file_group
           
    def _conflict_file(self, name, parent_id, tree, file_id, suffix, 
                       lines=None):
        """Emit a single conflict file."""
        name = name + '.' + suffix
        trans_id = self.tt.create_path(name, parent_id)
        entry = tree.inventory[file_id]
        create_by_entry(self.tt, entry, tree, trans_id, lines)
        return trans_id

    def merge_executable(self, file_id, file_status):
        """Perform a merge on the execute bit."""
        if file_status == "deleted":
            return
        trans_id = self.tt.trans_id_file_id(file_id)
        try:
            if self.tt.final_kind(trans_id) != "file":
                return
        except NoSuchFile:
            return
        winner = self.scalar_three_way(self.this_tree, self.base_tree, 
                                       self.other_tree, file_id, 
                                       self.executable)
        if winner == "conflict":
        # There must be a None in here, if we have a conflict, but we
        # need executability since file status was not deleted.
            if self.executable(self.other_tree, file_id) is None:
                winner = "this"
            else:
                winner = "other"
        if winner == "this":
            if file_status == "modified":
                executability = self.this_tree.is_executable(file_id)
                if executability is not None:
                    trans_id = self.tt.trans_id_file_id(file_id)
                    self.tt.set_executability(executability, trans_id)
        else:
            assert winner == "other"
            if file_id in self.other_tree:
                executability = self.other_tree.is_executable(file_id)
            elif file_id in self.this_tree:
                executability = self.this_tree.is_executable(file_id)
            elif file_id in self.base_tree:
                executability = self.base_tree.is_executable(file_id)
            if executability is not None:
                trans_id = self.tt.trans_id_file_id(file_id)
                self.tt.set_executability(executability, trans_id)

    def cook_conflicts(self, fs_conflicts):
        """Convert all conflicts into a form that doesn't depend on trans_id"""
        from conflicts import Conflict
        name_conflicts = {}
        self.cooked_conflicts.extend(cook_conflicts(fs_conflicts, self.tt))
        fp = FinalPaths(self.tt)
        for conflict in self._raw_conflicts:
            conflict_type = conflict[0]
            if conflict_type in ('name conflict', 'parent conflict'):
                trans_id = conflict[1]
                conflict_args = conflict[2:]
                if trans_id not in name_conflicts:
                    name_conflicts[trans_id] = {}
                unique_add(name_conflicts[trans_id], conflict_type, 
                           conflict_args)
            if conflict_type == 'contents conflict':
                for trans_id in conflict[1]:
                    file_id = self.tt.final_file_id(trans_id)
                    if file_id is not None:
                        break
                path = fp.get_path(trans_id)
                for suffix in ('.BASE', '.THIS', '.OTHER'):
                    if path.endswith(suffix):
                        path = path[:-len(suffix)]
                        break
                c = Conflict.factory(conflict_type, path=path, file_id=file_id)
                self.cooked_conflicts.append(c)
            if conflict_type == 'text conflict':
                trans_id = conflict[1]
                path = fp.get_path(trans_id)
                file_id = self.tt.final_file_id(trans_id)
                c = Conflict.factory(conflict_type, path=path, file_id=file_id)
                self.cooked_conflicts.append(c)

        for trans_id, conflicts in name_conflicts.iteritems():
            try:
                this_parent, other_parent = conflicts['parent conflict']
                assert this_parent != other_parent
            except KeyError:
                this_parent = other_parent = \
                    self.tt.final_file_id(self.tt.final_parent(trans_id))
            try:
                this_name, other_name = conflicts['name conflict']
                assert this_name != other_name
            except KeyError:
                this_name = other_name = self.tt.final_name(trans_id)
            other_path = fp.get_path(trans_id)
            if this_parent is not None:
                this_parent_path = \
                    fp.get_path(self.tt.trans_id_file_id(this_parent))
                this_path = pathjoin(this_parent_path, this_name)
            else:
                this_path = "<deleted>"
            file_id = self.tt.final_file_id(trans_id)
            c = Conflict.factory('path conflict', path=this_path,
                                 conflict_path=other_path, file_id=file_id)
            self.cooked_conflicts.append(c)
        self.cooked_conflicts.sort(key=Conflict.sort_key)


class WeaveMerger(Merge3Merger):
    """Three-way tree merger, text weave merger."""
    supports_reprocess = True
    supports_show_base = False

    def __init__(self, working_tree, this_tree, base_tree, other_tree, 
                 interesting_ids=None, pb=DummyProgress(), pp=None,
                 reprocess=False):
        self.this_revision_tree = self._get_revision_tree(this_tree)
        self.other_revision_tree = self._get_revision_tree(other_tree)
        super(WeaveMerger, self).__init__(working_tree, this_tree, 
                                          base_tree, other_tree, 
                                          interesting_ids=interesting_ids, 
                                          pb=pb, pp=pp, reprocess=reprocess)

    def _get_revision_tree(self, tree):
        """Return a revision tree related to this tree.
        If the tree is a WorkingTree, the basis will be returned.
        """
        if getattr(tree, 'get_weave', False) is False:
            # If we have a WorkingTree, try using the basis
            return tree.branch.basis_tree()
        else:
            return tree

    def _check_file(self, file_id):
        """Check that the revision tree's version of the file matches."""
        for tree, rt in ((self.this_tree, self.this_revision_tree), 
                         (self.other_tree, self.other_revision_tree)):
            if rt is tree:
                continue
            if tree.get_file_sha1(file_id) != rt.get_file_sha1(file_id):
                raise WorkingTreeNotRevision(self.this_tree)

    def _merged_lines(self, file_id):
        """Generate the merged lines.
        There is no distinction between lines that are meant to contain <<<<<<<
        and conflicts.
        """
        weave = self.this_revision_tree.get_weave(file_id)
        this_revision_id = self.this_revision_tree.inventory[file_id].revision
        other_revision_id = \
            self.other_revision_tree.inventory[file_id].revision
        wm = WeaveMerge(weave, this_revision_id, other_revision_id, 
                        '<<<<<<< TREE\n', '>>>>>>> MERGE-SOURCE\n')
        return wm.merge_lines(self.reprocess)

    def text_merge(self, file_id, trans_id):
        """Perform a (weave) text merge for a given file and file-id.
        If conflicts are encountered, .THIS and .OTHER files will be emitted,
        and a conflict will be noted.
        """
        self._check_file(file_id)
        lines, conflicts = self._merged_lines(file_id)
        lines = list(lines)
        # Note we're checking whether the OUTPUT is binary in this case, 
        # because we don't want to get into weave merge guts.
        check_text_lines(lines)
        self.tt.create_file(lines, trans_id)
        if conflicts:
            self._raw_conflicts.append(('text conflict', trans_id))
            name = self.tt.final_name(trans_id)
            parent_id = self.tt.final_parent(trans_id)
            file_group = self._dump_conflicts(name, parent_id, file_id, 
                                              no_base=True)
            file_group.append(trans_id)


class Diff3Merger(Merge3Merger):
    """Three-way merger using external diff3 for text merging"""

    def dump_file(self, temp_dir, name, tree, file_id):
        out_path = pathjoin(temp_dir, name)
        out_file = open(out_path, "wb")
        try:
            in_file = tree.get_file(file_id)
            for line in in_file:
                out_file.write(line)
        finally:
            out_file.close()
        return out_path

    def text_merge(self, file_id, trans_id):
        """Perform a diff3 merge using a specified file-id and trans-id.
        If conflicts are encountered, .BASE, .THIS. and .OTHER conflict files
        will be dumped, and a will be conflict noted.
        """
        import bzrlib.patch
        temp_dir = mkdtemp(prefix="bzr-")
        try:
            new_file = pathjoin(temp_dir, "new")
            this = self.dump_file(temp_dir, "this", self.this_tree, file_id)
            base = self.dump_file(temp_dir, "base", self.base_tree, file_id)
            other = self.dump_file(temp_dir, "other", self.other_tree, file_id)
            status = bzrlib.patch.diff3(new_file, this, base, other)
            if status not in (0, 1):
                raise BzrError("Unhandled diff3 exit code")
            f = open(new_file, 'rb')
            try:
                self.tt.create_file(f, trans_id)
            finally:
                f.close()
            if status == 1:
                name = self.tt.final_name(trans_id)
                parent_id = self.tt.final_parent(trans_id)
                self._dump_conflicts(name, parent_id, file_id)
            self._raw_conflicts.append(('text conflict', trans_id))
        finally:
            rmtree(temp_dir)


def merge_inner(this_branch, other_tree, base_tree, ignore_zero=False,
                backup_files=False, 
                merge_type=Merge3Merger, 
                interesting_ids=None, 
                show_base=False, 
                reprocess=False, 
                other_rev_id=None,
                interesting_files=None,
                this_tree=None,
                pb=DummyProgress()):
    """Primary interface for merging. 

        typical use is probably 
        'merge_inner(branch, branch.get_revision_tree(other_revision),
                     branch.get_revision_tree(base_revision))'
        """
    if this_tree is None:
        warnings.warn("bzrlib.merge.merge_inner requires a this_tree parameter as of "
             "bzrlib version 0.8.",
             DeprecationWarning,
             stacklevel=2)
        this_tree = this_branch.bzrdir.open_workingtree()
    merger = Merger(this_branch, other_tree, base_tree, this_tree=this_tree, 
                    pb=pb)
    merger.backup_files = backup_files
    merger.merge_type = merge_type
    merger.interesting_ids = interesting_ids
    merger.ignore_zero = ignore_zero
    if interesting_files:
        assert not interesting_ids, ('Only supply interesting_ids'
                                     ' or interesting_files')
        merger._set_interesting_files(interesting_files)
    merger.show_base = show_base
    merger.reprocess = reprocess
    merger.other_rev_id = other_rev_id
    merger.other_basis = other_rev_id
    return merger.do_merge()


merge_types = {     "merge3": (Merge3Merger, "Native diff3-style merge"), 
                     "diff3": (Diff3Merger,  "Merge using external diff3"),
                     'weave': (WeaveMerger, "Weave-based merge")
              }


def merge_type_help():
    templ = '%s%%7s: %%s' % (' '*12)
    lines = [templ % (f[0], f[1][1]) for f in merge_types.iteritems()]
    return '\n'.join(lines)
