~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 trace import mutter
from errors import BzrError


# 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

    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,
                              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 nonl:
        print >>to_file, "\\ No newline at end of file"
    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)



class TreeDelta(object):
    """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.

    Files are only considered renamed if their name has changed or
    their parent directory has changed.  Renaming a directory
    does not count as renaming all its contents.

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

    def __eq__(self, other):
        if not isinstance(other, TreeDelta):
            return False
        return self.added == other.added \
               and self.removed == other.removed \
               and self.renamed == other.renamed \
               and self.modified == other.modified \
               and self.unchanged == other.unchanged

    def __ne__(self, other):
        return not (self == other)

    def __repr__(self):
        return "TreeDelta(added=%r, removed=%r, renamed=%r, modified=%r," \
            " unchanged=%r)" % (self.added, self.removed, self.renamed,
            self.modified, self.unchanged)

    def has_changed(self):
        changes = len(self.added) + len(self.removed) + len(self.renamed)
        changes += len(self.modified) 
        return (changes != 0)

    def touches_file_id(self, file_id):
        """Return True if file_id is modified by this delta."""
        for l in self.added, self.removed, self.modified:
            for v in l:
                if v[1] == file_id:
                    return True
        for v in self.renamed:
            if v[2] == file_id:
                return True
        return False
            

    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=False, specific_files=None):
    """Describe changes from one tree to another.

    Returns a TreeDelta with details of added, modified, renamed, and
    deleted entries.

    The root entry is specifically exempt.

    This only considers versioned files.

    want_unchanged
        If true, also list files unchanged from one version to
        the next.

    specific_files
        If true, only check for changes to specified names or
        files within them.
    """

    from osutils import is_inside_any
    
    old_inv = old_tree.inventory
    new_inv = new_tree.inventory
    delta = TreeDelta()
    mutter('start compare_trees')

    # TODO: match for specific files can be rather smarter by finding
    # the IDs of those files up front and then considering only that.

    for file_id in old_tree:
        if file_id in new_tree:
            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 == 'root_directory':
                continue
            
            old_path = old_inv.id2path(file_id)
            new_path = new_inv.id2path(file_id)

            old_ie = old_inv[file_id]
            new_ie = new_inv[file_id]

            if specific_files:
                if (not is_inside_any(specific_files, old_path) 
                    and not is_inside_any(specific_files, new_path)):
                    continue

            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_ie.name != new_ie.name
                or old_ie.parent_id != new_ie.parent_id):
                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:
            kind = old_inv.get_file_kind(file_id)
            old_path = old_inv.id2path(file_id)
            if specific_files:
                if not is_inside_any(specific_files, old_path):
                    continue
            delta.removed.append((old_path, file_id, kind))

    mutter('start looking for new files')
    for file_id in new_inv:
        if file_id in old_inv:
            continue
        new_path = new_inv.id2path(file_id)
        if specific_files:
            if not is_inside_any(specific_files, new_path):
                continue
        kind = new_inv.get_file_kind(file_id)
        delta.added.append((new_path, file_id, kind))
            
    delta.removed.sort()
    delta.added.sort()
    delta.renamed.sort()
    delta.modified.sort()
    delta.unchanged.sort()

    return delta