~bzr-pqm/bzr/bzr.dev

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#! /usr/bin/env python
# -*- coding: UTF-8 -*-

# 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

from sets import Set

from trace import mutter
from errors import BzrError


def diff_trees(old_tree, new_tree):
    """Compute diff between two trees.

    They may be in different branches and may be working or historical
    trees.

    This only compares the versioned files, paying no attention to
    files which are ignored or unknown.  Those can only be present in
    working trees and can be reported on separately.

    Yields a sequence of (state, id, old_name, new_name, kind).
    Each filename and each id is listed only once.
    """
    ## TODO: Allow specifying a list of files to compare, rather than
    ## doing the whole tree?  (Not urgent.)

    ## TODO: Allow diffing any two inventories, not just the
    ## current one against one.  We mgiht need to specify two
    ## stores to look for the files if diffing two branches.  That
    ## might imply this shouldn't be primarily a Branch method.

    sha_match_cnt = modified_cnt = 0

    old_it = old_tree.list_files()
    new_it = new_tree.list_files()

    def next(it):
        try:
            return it.next()
        except StopIteration:
            return None

    old_item = next(old_it)
    new_item = next(new_it)

    # We step through the two sorted iterators in parallel, trying to
    # keep them lined up.

    while (old_item != None) or (new_item != None):
        # OK, we still have some remaining on both, but they may be
        # out of step.        
        if old_item != None:
            old_name, old_class, old_kind, old_id = old_item
        else:
            old_name = None
            
        if new_item != None:
            new_name, new_class, new_kind, new_id = new_item
        else:
            new_name = None

        if old_item:
            # can't handle the old tree being a WorkingTree
            assert old_class == 'V'

        if new_item and (new_class != 'V'):
            yield new_class, None, None, new_name, new_kind
            new_item = next(new_it)
        elif (not new_item) or (old_item and (old_name < new_name)):
            if new_tree.has_id(old_id):
                # will be mentioned as renamed under new name
                pass
            else:
                yield 'D', old_id, old_name, None, old_kind
            old_item = next(old_it)
        elif (not old_item) or (new_item and (new_name < old_name)):
            if old_tree.has_id(new_id):
                yield 'R', new_id, old_tree.id2path(new_id), new_name, new_kind
            else:
                yield 'A', new_id, None, new_name, new_kind
            new_item = next(new_it)
        elif old_id != new_id:
            assert old_name == new_name
            # both trees have a file of this name, but it is not the
            # same file.  in other words, the old filename has been
            # overwritten by either a newly-added or a renamed file.
            # (should we return something about the overwritten file?)
            if old_tree.has_id(new_id):
                # renaming, overlying a deleted file
                yield 'R', new_id, old_tree.id2path(new_id), new_name, new_kind
            else:
                yield 'A', new_id, None, new_name, new_kind

            new_item = next(new_it)
            old_item = next(old_it)
        else:
            assert old_id == new_id
            assert old_id != None
            assert old_name == new_name
            assert old_kind == new_kind

            if old_kind == 'directory':
                yield '.', new_id, old_name, new_name, new_kind
            elif old_tree.get_file_sha1(old_id) == new_tree.get_file_sha1(old_id):
                sha_match_cnt += 1
                yield '.', new_id, old_name, new_name, new_kind
            else:
                modified_cnt += 1
                yield 'M', new_id, old_name, new_name, new_kind

            new_item = next(new_it)
            old_item = next(old_it)


    mutter("diff finished: %d SHA matches, %d modified"
           % (sha_match_cnt, modified_cnt))



def _diff_one(oldlines, newlines, to_file, **kw):
    import difflib
    
    # FIXME: difflib is wrong if there is no trailing newline.
    # The syntax used by patch seems to be "\ No newline at
    # end of file" following the last diff line from that
    # file.  This is not trivial to insert into the
    # unified_diff output and it might be better to just fix
    # or replace that function.

    # In the meantime we at least make sure the patch isn't
    # mangled.


    # Special workaround for Python2.3, where difflib fails if
    # both sequences are empty.
    if not oldlines and not newlines:
        return

    nonl = False

    if oldlines and (oldlines[-1][-1] != '\n'):
        oldlines[-1] += '\n'
        nonl = True
    if newlines and (newlines[-1][-1] != '\n'):
        newlines[-1] += '\n'
        nonl = True

    ud = difflib.unified_diff(oldlines, newlines, **kw)

    # work-around for difflib being too smart for its own good
    # if /dev/null is "1,0", patch won't recognize it as /dev/null
    if not oldlines:
        ud = list(ud)
        ud[2] = ud[2].replace('-1,0', '-0,0')
    elif not newlines:
        ud = list(ud)
        ud[2] = ud[2].replace('+1,0', '+0,0')

    to_file.writelines(ud)
    if nonl:
        print >>to_file, "\\ No newline at end of file"
    print >>to_file


def show_diff(b, revision, file_list):
    import sys

    if file_list:
        raise NotImplementedError('diff on restricted files broken at the moment')
    
    if revision == None:
        old_tree = b.basis_tree()
    else:
        old_tree = b.revision_tree(b.lookup_revision(revision))
        
    new_tree = b.working_tree()

    # TODO: Options to control putting on a prefix or suffix, perhaps as a format string
    old_label = ''
    new_label = ''

    DEVNULL = '/dev/null'
    # Windows users, don't panic about this filename -- it is a
    # special signal to GNU patch that the file should be created or
    # deleted respectively.

    # TODO: Generation of pseudo-diffs for added/deleted files could
    # be usefully made into a much faster special case.

    delta = compare_trees(old_tree, new_tree, want_unchanged=False)

    for path, file_id, kind in delta.removed:
        print '*** removed %s %r' % (kind, path)
        if kind == 'file':
            _diff_one(old_tree.get_file(file_id).readlines(),
                   [],
                   sys.stdout,
                   fromfile=old_label + path,
                   tofile=DEVNULL)

    for path, file_id, kind in delta.added:
        print '*** added %s %r' % (kind, path)
        if kind == 'file':
            _diff_one([],
                   new_tree.get_file(file_id).readlines(),
                   sys.stdout,
                   fromfile=DEVNULL,
                   tofile=new_label + path)

    for old_path, new_path, file_id, kind, text_modified in delta.renamed:
        print '*** renamed %s %r => %r' % (kind, old_path, new_path)
        if text_modified:
            _diff_one(old_tree.get_file(file_id).readlines(),
                   new_tree.get_file(file_id).readlines(),
                   sys.stdout,
                   fromfile=old_label + old_path,
                   tofile=new_label + new_path)

    for path, file_id, kind in delta.modified:
        print '*** modified %s %r' % (kind, path)
        if kind == 'file':
            _diff_one(old_tree.get_file(file_id).readlines(),
                   new_tree.get_file(file_id).readlines(),
                   sys.stdout,
                   fromfile=old_label + path,
                   tofile=new_label + path)



class TreeDelta:
    """Describes changes from one tree to another.

    Contains four lists:

    added
        (path, id, kind)
    removed
        (path, id, kind)
    renamed
        (oldpath, newpath, id, kind, text_modified)
    modified
        (path, id, kind)
    unchanged
        (path, id, kind)

    Each id is listed only once.

    Files that are both modified and renamed are listed only in
    renamed, with the text_modified flag true.

    The lists are normally sorted when the delta is created.
    """
    def __init__(self):
        self.added = []
        self.removed = []
        self.renamed = []
        self.modified = []
        self.unchanged = []

    def show(self, to_file, show_ids=False, show_unchanged=False):
        def show_list(files):
            for path, fid, kind in files:
                if kind == 'directory':
                    path += '/'
                elif kind == 'symlink':
                    path += '@'
                    
                if show_ids:
                    print >>to_file, '  %-30s %s' % (path, fid)
                else:
                    print >>to_file, ' ', path
            
        if self.removed:
            print >>to_file, 'removed:'
            show_list(self.removed)
                
        if self.added:
            print >>to_file, 'added:'
            show_list(self.added)

        if self.renamed:
            print >>to_file, 'renamed:'
            for oldpath, newpath, fid, kind, text_modified in self.renamed:
                if show_ids:
                    print >>to_file, '  %s => %s %s' % (oldpath, newpath, fid)
                else:
                    print >>to_file, '  %s => %s' % (oldpath, newpath)
                    
        if self.modified:
            print >>to_file, 'modified:'
            show_list(self.modified)
            
        if show_unchanged and self.unchanged:
            print >>to_file, 'unchanged:'
            show_list(self.unchanged)



def compare_trees(old_tree, new_tree, want_unchanged):
    old_inv = old_tree.inventory
    new_inv = new_tree.inventory
    delta = TreeDelta()
    mutter('start compare_trees')
    for file_id in old_tree:
        if file_id in new_tree:
            old_path = old_inv.id2path(file_id)
            new_path = new_inv.id2path(file_id)

            kind = old_inv.get_file_kind(file_id)
            assert kind == new_inv.get_file_kind(file_id)
            
            assert kind in ('file', 'directory', 'symlink', 'root_directory'), \
                   'invalid file kind %r' % kind
            if kind == 'file':
                old_sha1 = old_tree.get_file_sha1(file_id)
                new_sha1 = new_tree.get_file_sha1(file_id)
                text_modified = (old_sha1 != new_sha1)
            else:
                ## mutter("no text to check for %r %r" % (file_id, kind))
                text_modified = False

            # TODO: Can possibly avoid calculating path strings if the
            # two files are unchanged and their names and parents are
            # the same and the parents are unchanged all the way up.
            # May not be worthwhile.
            
            if old_path != new_path:
                delta.renamed.append((old_path, new_path, file_id, kind,
                                      text_modified))
            elif text_modified:
                delta.modified.append((new_path, file_id, kind))
            elif want_unchanged:
                delta.unchanged.append((new_path, file_id, kind))
        else:
            delta.removed.append((old_inv.id2path(file_id), file_id, kind))

    mutter('start looking for new files')
    for file_id in new_inv:
        if file_id in old_inv:
            continue
        kind = new_inv.get_file_kind(file_id)
        delta.added.append((new_inv.id2path(file_id), file_id, kind))
            
    delta.removed.sort()
    delta.added.sort()
    delta.renamed.sort()
    delta.modified.sort()
    delta.unchanged.sort()

    return delta