~bzr-pqm/bzr/bzr.dev

#! /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 bzrlib.trace import mutter

from bzrlib.errors import BzrError

from bzrlib.delta import compare_trees

# TODO: Rather than building a changeset object, we should probably

# invoke callbacks on an object.  That object can either accumulate a

# list, write them out directly, etc etc.

def internal_diff(old_label, oldlines, new_label, newlines, to_file):

    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

    ud = difflib.unified_diff(oldlines, newlines,

                              fromfile=old_label, tofile=new_label)

    # 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')

    for line in ud:

        to_file.write(line)

        if not line.endswith('\n'):

            to_file.write("\n\\ No newline at end of file\n")

    print >>to_file

def external_diff(old_label, oldlines, new_label, newlines, to_file,

                  diff_opts):

    """Display a diff by calling out to the external diff program."""

    import sys

    if to_file != sys.stdout:

        raise NotImplementedError("sorry, can't send external diff other than to stdout yet",

                                  to_file)

    # make sure our own output is properly ordered before the diff

    to_file.flush()

    from tempfile import NamedTemporaryFile

    import os

    oldtmpf = NamedTemporaryFile()

    newtmpf = NamedTemporaryFile()

    try:

        # TODO: perhaps a special case for comparing to or from the empty

        # sequence; can just use /dev/null on Unix

        # TODO: if either of the files being compared already exists as a

        # regular named file (e.g. in the working directory) then we can

        # compare directly to that, rather than copying it.

        oldtmpf.writelines(oldlines)

        newtmpf.writelines(newlines)

        oldtmpf.flush()

        newtmpf.flush()

        if not diff_opts:

            diff_opts = []

        diffcmd = ['diff',

                   '--label', old_label,

                   oldtmpf.name,

                   '--label', new_label,

                   newtmpf.name]

        # diff only allows one style to be specified; they don't override.

        # note that some of these take optargs, and the optargs can be

        # directly appended to the options.

        # this is only an approximate parser; it doesn't properly understand

        # the grammar.

        for s in ['-c', '-u', '-C', '-U',

                  '-e', '--ed',

                  '-q', '--brief',

                  '--normal',

                  '-n', '--rcs',

                  '-y', '--side-by-side',

                  '-D', '--ifdef']:

            for j in diff_opts:

                if j.startswith(s):

                    break

            else:

                continue

            break

        else:

            diffcmd.append('-u')

        if diff_opts:

            diffcmd.extend(diff_opts)

        rc = os.spawnvp(os.P_WAIT, 'diff', diffcmd)

        if rc != 0 and rc != 1:

            # returns 1 if files differ; that's OK

            if rc < 0:

                msg = 'signal %d' % (-rc)

            else:

                msg = 'exit code %d' % rc

            raise BzrError('external diff failed with %s; command: %r' % (rc, diffcmd))

    finally:

        oldtmpf.close()                 # and delete

        newtmpf.close()

def show_diff(b, revision, specific_files, external_diff_options=None):

    """Shortcut for showing the diff to the working tree.

    b

        Branch.

    revision

        None for each, or otherwise the old revision to compare against.

    The more general form is show_diff_trees(), where the caller

    supplies any two trees.

    """

    import sys

    if revision == None:

        old_tree = b.basis_tree()

    else:

        old_tree = b.revision_tree(b.lookup_revision(revision))

    new_tree = b.working_tree()

    show_diff_trees(old_tree, new_tree, sys.stdout, specific_files,

                    external_diff_options)

def show_diff_trees(old_tree, new_tree, to_file, specific_files=None,

                    external_diff_options=None):

    """Show in text form the changes from one tree to another.

    to_files

        If set, include only changes to these files.

    external_diff_options

        If set, use an external GNU diff and pass these options.

    """

    # 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.

    if external_diff_options:

        assert isinstance(external_diff_options, basestring)

        opts = external_diff_options.split()

        def diff_file(olab, olines, nlab, nlines, to_file):

            external_diff(olab, olines, nlab, nlines, to_file, opts)

    else:

        diff_file = internal_diff

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

                          specific_files=specific_files)

    for path, file_id, kind in delta.removed:

        print >>to_file, '*** removed %s %r' % (kind, path)

        if kind == 'file':

            diff_file(old_label + path,

                      old_tree.get_file(file_id).readlines(),

                      DEVNULL, 

                      [],

                      to_file)

    for path, file_id, kind in delta.added:

        print >>to_file, '*** added %s %r' % (kind, path)

        if kind == 'file':

            diff_file(DEVNULL,

                      [],

                      new_label + path,

                      new_tree.get_file(file_id).readlines(),

                      to_file)

    for old_path, new_path, file_id, kind, text_modified in delta.renamed:

        print >>to_file, '*** renamed %s %r => %r' % (kind, old_path, new_path)

        if text_modified:

            diff_file(old_label + old_path,

                      old_tree.get_file(file_id).readlines(),

                      new_label + new_path,

                      new_tree.get_file(file_id).readlines(),

                      to_file)

    for path, file_id, kind in delta.modified:

        print >>to_file, '*** modified %s %r' % (kind, path)

        if kind == 'file':

            diff_file(old_label + path,

                      old_tree.get_file(file_id).readlines(),

                      new_label + path,

                      new_tree.get_file(file_id).readlines(),

                      to_file)