~bzr-pqm/bzr/bzr.dev

# 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

import os

import tempfile

import shutil

import errno

import bzrlib.osutils

import bzrlib.revision

from bzrlib.merge_core import merge_flex, ApplyMerge3, BackupBeforeChange

from bzrlib.changeset import generate_changeset, ExceptionConflictHandler

from bzrlib.changeset import Inventory, Diff3Merge, ReplaceContents

from bzrlib.branch import Branch

from bzrlib.errors import BzrCommandError, UnrelatedBranches, NoCommonAncestor

from bzrlib.errors import NoCommits

from bzrlib.delta import compare_trees

from bzrlib.trace import mutter, warning, note

from bzrlib.fetch import greedy_fetch, fetch

from bzrlib.revision import is_ancestor

from bzrlib.osutils import rename

from bzrlib.revision import common_ancestor, MultipleRevisionSources

from bzrlib.errors import NoSuchRevision

# TODO: build_working_dir can be built on something simpler than merge()

# FIXME: merge() parameters seem oriented towards the command line

# NOTABUG: merge is a helper for commandline functions.  merge_inner is the

#          the core functionality.

# comments from abentley on irc: merge happens in two stages, each

# of which generates a changeset object

# stage 1: generate OLD->OTHER,

# stage 2: use MINE and OLD->OTHER to generate MINE -> RESULT

class MergeConflictHandler(ExceptionConflictHandler):

    """Handle conflicts encountered while merging.

    This subclasses ExceptionConflictHandler, so that any types of

    conflict that are not explicitly handled cause an exception and

    terminate the merge.

    """

    def __init__(self, this_tree, base_tree, other_tree, ignore_zero=False):

        ExceptionConflictHandler.__init__(self)

        self.conflicts = 0

        self.ignore_zero = ignore_zero

        self.this_tree = this_tree

        self.base_tree = base_tree

        self.other_tree = other_tree

    def copy(self, source, dest):

        """Copy the text and mode of a file

        :param source: The path of the file to copy

        :param dest: The distination file to create

        """

        s_file = file(source, "rb")

        d_file = file(dest, "wb")

        for line in s_file:

            d_file.write(line)

        os.chmod(dest, 0777 & os.stat(source).st_mode)

    def dump(self, lines, dest):

        """Copy the text and mode of a file

        :param source: The path of the file to copy

        :param dest: The distination file to create

        """

        d_file = file(dest, "wb")

        for line in lines:

            d_file.write(line)

    def add_suffix(self, name, suffix, last_new_name=None):

        """Rename a file to append a suffix.  If the new name exists, the

        suffix is added repeatedly until a non-existant name is found

        :param name: The path of the file

        :param suffix: The suffix to append

        :param last_new_name: (used for recursive calls) the last name tried

        """

        if last_new_name is None:

            last_new_name = name

        new_name = last_new_name+suffix

        try:

            rename(name, new_name)

            return new_name

        except OSError, e:

            if e.errno != errno.EEXIST and e.errno != errno.ENOTEMPTY:

                raise

            return self.add_suffix(name, suffix, last_new_name=new_name)

    def conflict(self, text):

        warning(text)

        self.conflicts += 1

    def merge_conflict(self, new_file, this_path, base_lines, other_lines):

        """

        Handle diff3 conflicts by producing a .THIS, .BASE and .OTHER.  The

        main file will be a version with diff3 conflicts.

        :param new_file: Path to the output file with diff3 markers

        :param this_path: Path to the file text for the THIS tree

        :param base_path: Path to the file text for the BASE tree

        :param other_path: Path to the file text for the OTHER tree

        """

        self.add_suffix(this_path, ".THIS")

        self.dump(base_lines, this_path+".BASE")

        self.dump(other_lines, this_path+".OTHER")

        rename(new_file, this_path)

        self.conflict("Diff3 conflict encountered in %s" % this_path)

    def new_contents_conflict(self, filename, other_contents):

        """Conflicting contents for newly added file."""

        other.contents.apply(filename + ".OTHER")

        self.conflict("Conflict in newly added file %s" % filename)

    def target_exists(self, entry, target, old_path):

        """Handle the case when the target file or dir exists"""

        moved_path = self.add_suffix(target, ".moved")

        self.conflict("Moved existing %s to %s" % (target, moved_path))

    def rmdir_non_empty(self, filename):

        """Handle the case where the dir to be removed still has contents"""

        self.conflict("Directory %s not removed because it is not empty"\

            % filename)

        return "skip"

    def rem_contents_conflict(self, filename, this_contents, base_contents):

        base_contents(filename+".BASE", self, False)

        this_contents(filename+".THIS", self, False)

        return ReplaceContents(this_contents, None)

    def rem_contents_conflict(self, filename, this_contents, base_contents):

        base_contents(filename+".BASE", self, False)

        this_contents(filename+".THIS", self, False)

        self.conflict("Other branch deleted locally modified file %s" %

                      filename)

        return ReplaceContents(this_contents, None)

    def abs_this_path(self, file_id):

        """Return the absolute path for a file_id in the this tree."""

        return self.this_tree.id2abspath(file_id)

    def add_missing_parents(self, file_id, tree):

        """If some of the parents for file_id are missing, add them."""

        entry = tree.inventory[file_id]

        if entry.parent_id not in self.this_tree:

            return self.create_all_missing(entry.parent_id, tree)

        else:

            return self.abs_this_path(entry.parent_id)

    def create_all_missing(self, file_id, tree):

        """Add contents for a file_id and all its parents to a tree."""

        entry = tree.inventory[file_id]

        if entry.parent_id is not None and entry.parent_id not in self.this_tree:

            abspath = self.create_all_missing(entry.parent_id, tree)

        else:

            abspath = self.abs_this_path(entry.parent_id)

        entry_path = os.path.join(abspath, entry.name)

        if not os.path.isdir(entry_path):

            self.create(file_id, entry_path, tree)

        return entry_path

    def create(self, file_id, path, tree, reverse=False):

        """Uses tree data to create a filesystem object for the file_id"""

        from changeset import get_contents

        get_contents(tree, file_id)(path, self, reverse)

    def missing_for_merge(self, file_id, other_path):

        """The file_id doesn't exist in THIS, but does in OTHER and BASE"""

        self.conflict("Other branch modified locally deleted file %s" %

                      other_path)

        parent_dir = self.add_missing_parents(file_id, self.other_tree)

        stem = os.path.join(parent_dir, os.path.basename(other_path))

        self.create(file_id, stem+".OTHER", self.other_tree)

        self.create(file_id, stem+".BASE", self.base_tree)

    def threeway_contents_conflict(filename, this_contents, base_contents,

                                   other_contents):

        self.conflict("Three-way conflict merging %s" % filename)

    def finalize(self):

        if not self.ignore_zero:

            note("%d conflicts encountered.\n" % self.conflicts)

def get_tree(treespec, local_branch=None):

    location, revno = treespec

    branch = Branch.open_containing(location)[0]

    if revno is None:

        revision = None

    elif revno == -1:

        revision = branch.last_revision()

    else:

        revision = branch.get_rev_id(revno)

    return branch, get_revid_tree(branch, revision, local_branch)

def get_revid_tree(branch, revision, local_branch):

    if revision is None:

        base_tree = branch.working_tree()

    else:

        if local_branch is not None:

            greedy_fetch(local_branch, branch, revision)

            base_tree = local_branch.revision_tree(revision)

        else:

            base_tree = branch.revision_tree(revision)

    return base_tree

def file_exists(tree, file_id):

    return tree.has_filename(tree.id2path(file_id))

def build_working_dir(to_dir):

    """Build a working directory in an empty directory.

    to_dir is a directory containing branch metadata but no working files,

    typically constructed by cloning an existing branch. 

    This is split out as a special idiomatic case of merge.  It could

    eventually be done by just building the tree directly calling into 

    lower-level code (e.g. constructing a changeset).

    """

    merge((to_dir, -1), (to_dir, 0), this_dir=to_dir,

          check_clean=False, ignore_zero=True)

def merge(other_revision, base_revision,

          check_clean=True, ignore_zero=False,

          this_dir=None, backup_files=False, merge_type=ApplyMerge3,

          file_list=None):

    """Merge changes into a tree.

    base_revision

        tuple(path, revision) Base for three-way merge.

    other_revision

        tuple(path, revision) Other revision for three-way merge.

    this_dir

        Directory to merge changes into; '.' by default.

    check_clean

        If true, this_dir must have no uncommitted changes before the

        merge begins.

    ignore_zero - If true, suppress the "zero conflicts" message when 

        there are no conflicts; should be set when doing something we expect

        to complete perfectly.

    All available ancestors of other_revision and base_revision are

    automatically pulled into the branch.

    """

    tempdir = tempfile.mkdtemp(prefix="bzr-")

    try:

        if this_dir is None:

            this_dir = '.'

        this_branch = Branch.open_containing(this_dir)[0]

        this_rev_id = this_branch.last_revision()

        if this_rev_id is None:

            raise BzrCommandError("This branch has no commits")

        if check_clean:

            changes = compare_trees(this_branch.working_tree(), 

                                    this_branch.basis_tree(), False)

            if changes.has_changed():

                raise BzrCommandError("Working tree has uncommitted changes.")

        other_branch, other_tree = get_tree(other_revision, this_branch)

        if other_revision[1] == -1:

            other_rev_id = other_branch.last_revision()

            if other_rev_id is None:

                raise NoCommits(other_branch)

            other_basis = other_rev_id

        elif other_revision[1] is not None:

            other_rev_id = other_branch.get_rev_id(other_revision[1])

            other_basis = other_rev_id

        else:

            other_rev_id = None

            other_basis = other_branch.last_revision()

            if other_basis is None:

                raise NoCommits(other_branch)

        if base_revision == [None, None]:

            try:

                base_rev_id = common_ancestor(this_rev_id, other_basis, 

                                              this_branch)

            except NoCommonAncestor:

                raise UnrelatedBranches()

            base_tree = get_revid_tree(this_branch, base_rev_id, None)

            base_is_ancestor = True

        else:

            base_branch, base_tree = get_tree(base_revision)

            if base_revision[1] == -1:

                base_rev_id = base_branch.last_revision()

            elif base_revision[1] is None:

                base_rev_id = None

            else:

                base_rev_id = base_branch.get_rev_id(base_revision[1])

            fetch(from_branch=base_branch, to_branch=this_branch)

            base_is_ancestor = is_ancestor(this_rev_id, base_rev_id,

                                           this_branch)

        if file_list is None:

            interesting_ids = None

        else:

            interesting_ids = set()

            this_tree = this_branch.working_tree()

            for fname in file_list:

                path = this_tree.relpath(fname)

                found_id = False

                for tree in (this_tree, base_tree, 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 BzrCommandError("%s is not a source file in any"

                                          " tree." % fname)

        merge_inner(this_branch, other_tree, base_tree, tempdir, 

                    ignore_zero=ignore_zero, backup_files=backup_files, 

                    merge_type=merge_type, interesting_ids=interesting_ids)

        if base_is_ancestor and other_rev_id is not None\

            and other_rev_id not in this_branch.revision_history():

            this_branch.add_pending_merge(other_rev_id)

    finally:

        shutil.rmtree(tempdir)

def set_interesting(inventory_a, inventory_b, interesting_ids):

    """Mark files whose ids are in interesting_ids as interesting

    """

    for inventory in (inventory_a, inventory_b):

        for path, source_file in inventory.iteritems():

             source_file.interesting = source_file.id in interesting_ids

def merge_inner(this_branch, other_tree, base_tree, tempdir, 

                ignore_zero=False, merge_type=ApplyMerge3, backup_files=False,

                interesting_ids=None):

    def merge_factory(file_id, base, other):

        contents_change = merge_type(file_id, base, other)

        if backup_files:

            contents_change = BackupBeforeChange(contents_change)

        return contents_change

    this_tree = get_tree((this_branch.base, None))[1]

    def get_inventory(tree):

        return tree.inventory

    inv_changes = merge_flex(this_tree, base_tree, other_tree,

                             generate_changeset, get_inventory,

                             MergeConflictHandler(this_tree, base_tree,

                             other_tree, ignore_zero=ignore_zero),

                             merge_factory=merge_factory, 

                             interesting_ids=interesting_ids)

    adjust_ids = []

    for id, path in inv_changes.iteritems():

        if path is not None:

            if path == '.':

                path = ''

            else:

                assert path.startswith('.' + os.sep), "path is %s" % path

            path = path[2:]

        adjust_ids.append((path, id))

    if len(adjust_ids) > 0:

        this_branch.set_inventory(regen_inventory(this_branch, 

                                                  this_tree.basedir,

                                                  adjust_ids))

def regen_inventory(this_branch, root, new_entries):

    old_entries = this_branch.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 os.path.join(id2path(entry.parent_id), entry.name)

    for file_id in old_entries:

        entry = old_entries[file_id]

        path = id2path(file_id)

        new_inventory[file_id] = (path, file_id, entry.parent_id, entry.kind)

        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)]

        kind = bzrlib.osutils.file_kind(os.path.join(root, path))

        new_inventory[file_id] = (path, file_id, parent, kind)

        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

merge_types = {     "merge3": (ApplyMerge3, "Native diff3-style merge"), 

                     "diff3": (Diff3Merge,  "Merge using external diff3")

              }