~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2004, 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 difflib

import os

import re

import sys

from bzrlib.lazy_import import lazy_import

lazy_import(globals(), """

import errno

import subprocess

import tempfile

import time

from bzrlib import (

    errors,

    osutils,

    patiencediff,

    textfile,

    timestamp,

    )

""")

from bzrlib.symbol_versioning import (

        deprecated_function,

        )

from bzrlib.trace import mutter, warning

# 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.

class _PrematchedMatcher(difflib.SequenceMatcher):

    """Allow SequenceMatcher operations to use predetermined blocks"""

    def __init__(self, matching_blocks):

        difflib.SequenceMatcher(self, None, None)

        self.matching_blocks = matching_blocks

        self.opcodes = None

def internal_diff(old_filename, oldlines, new_filename, newlines, to_file,

                  allow_binary=False, sequence_matcher=None,

                  path_encoding='utf8'):

    # 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

    if allow_binary is False:

        textfile.check_text_lines(oldlines)

        textfile.check_text_lines(newlines)

    if sequence_matcher is None:

        sequence_matcher = patiencediff.PatienceSequenceMatcher

    ud = patiencediff.unified_diff(oldlines, newlines,

                      fromfile=old_filename.encode(path_encoding),

                      tofile=new_filename.encode(path_encoding),

                      sequencematcher=sequence_matcher)

    ud = list(ud)

    if len(ud) == 0: # Identical contents, nothing to do

        return

    # 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[2] = ud[2].replace('-1,0', '-0,0')

    elif not newlines:

        ud[2] = ud[2].replace('+1,0', '+0,0')

    # work around for difflib emitting random spaces after the label

    ud[0] = ud[0][:-2] + '\n'

    ud[1] = ud[1][:-2] + '\n'

    for line in ud:

        to_file.write(line)

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

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

    to_file.write('\n')

def _spawn_external_diff(diffcmd, capture_errors=True):

    """Spawn the externall diff process, and return the child handle.

    :param diffcmd: The command list to spawn

    :param capture_errors: Capture stderr as well as setting LANG=C

        and LC_ALL=C. This lets us read and understand the output of diff,

        and respond to any errors.

    :return: A Popen object.

    """

    if capture_errors:

        # construct minimal environment

        env = {}

        path = os.environ.get('PATH')

        if path is not None:

            env['PATH'] = path

        env['LANGUAGE'] = 'C'   # on win32 only LANGUAGE has effect

        env['LANG'] = 'C'

        env['LC_ALL'] = 'C'

        stderr = subprocess.PIPE

    else:

        env = None

        stderr = None

    try:

        pipe = subprocess.Popen(diffcmd,

                                stdin=subprocess.PIPE,

                                stdout=subprocess.PIPE,

                                stderr=stderr,

                                env=env)

    except OSError, e:

        if e.errno == errno.ENOENT:

            raise errors.NoDiff(str(e))

        raise

    return pipe

def external_diff(old_filename, oldlines, new_filename, newlines, to_file,

                  diff_opts):

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

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

    to_file.flush()

    oldtmp_fd, old_abspath = tempfile.mkstemp(prefix='bzr-diff-old-')

    newtmp_fd, new_abspath = tempfile.mkstemp(prefix='bzr-diff-new-')

    oldtmpf = os.fdopen(oldtmp_fd, 'wb')

    newtmpf = os.fdopen(newtmp_fd, 'wb')

    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.close()

        newtmpf.close()

        if not diff_opts:

            diff_opts = []

        diffcmd = ['diff',

                   '--label', old_filename,

                   old_abspath,

                   '--label', new_filename,

                   new_abspath,

                   '--binary',

                  ]

        # 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)

        pipe = _spawn_external_diff(diffcmd, capture_errors=True)

        out,err = pipe.communicate()

        rc = pipe.returncode

        # internal_diff() adds a trailing newline, add one here for consistency

        out += '\n'

        if rc == 2:

            # 'diff' gives retcode == 2 for all sorts of errors

            # one of those is 'Binary files differ'.

            # Bad options could also be the problem.

            # 'Binary files' is not a real error, so we suppress that error.

            lang_c_out = out

            # Since we got here, we want to make sure to give an i18n error

            pipe = _spawn_external_diff(diffcmd, capture_errors=False)

            out, err = pipe.communicate()

            # Write out the new i18n diff response

            to_file.write(out+'\n')

            if pipe.returncode != 2:

                raise errors.BzrError(

                               'external diff failed with exit code 2'

                               ' when run with LANG=C and LC_ALL=C,'

                               ' but not when run natively: %r' % (diffcmd,))

            first_line = lang_c_out.split('\n', 1)[0]

            # Starting with diffutils 2.8.4 the word "binary" was dropped.

            m = re.match('^(binary )?files.*differ$', first_line, re.I)

            if m is None:

                raise errors.BzrError('external diff failed with exit code 2;'

                                      ' command: %r' % (diffcmd,))

            else:

                # Binary files differ, just return

                return

        # If we got to here, we haven't written out the output of diff

        # do so now

        to_file.write(out)

        if rc not in (0, 1):

            # returns 1 if files differ; that's OK

            if rc < 0:

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

            else:

                msg = 'exit code %d' % rc

            raise errors.BzrError('external diff failed with %s; command: %r' 

                                  % (rc, diffcmd))

    finally:

        oldtmpf.close()                 # and delete

        newtmpf.close()

        # Clean up. Warn in case the files couldn't be deleted

        # (in case windows still holds the file open, but not

        # if the files have already been deleted)

        try:

            os.remove(old_abspath)

        except OSError, e:

            if e.errno not in (errno.ENOENT,):

                warning('Failed to delete temporary file: %s %s',

                        old_abspath, e)

        try:

            os.remove(new_abspath)

        except OSError:

            if e.errno not in (errno.ENOENT,):

                warning('Failed to delete temporary file: %s %s',

                        new_abspath, e)

def diff_cmd_helper(tree, specific_files, external_diff_options, 

                    old_revision_spec=None, new_revision_spec=None,

                    revision_specs=None,

                    old_label='a/', new_label='b/'):

    """Helper for cmd_diff.

    :param tree:

        A WorkingTree

    :param specific_files:

        The specific files to compare, or None

    :param external_diff_options:

        If non-None, run an external diff, and pass it these options

    :param old_revision_spec:

        If None, use basis tree as old revision, otherwise use the tree for

        the specified revision. 

    :param new_revision_spec:

        If None, use working tree as new revision, otherwise use the tree for

        the specified revision.

    :param revision_specs: 

        Zero, one or two RevisionSpecs from the command line, saying what revisions 

        to compare.  This can be passed as an alternative to the old_revision_spec 

        and new_revision_spec parameters.

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

    supplies any two trees.

    """

    # TODO: perhaps remove the old parameters old_revision_spec and

    # new_revision_spec, since this is only really for use from cmd_diff and

    # it now always passes through a sequence of revision_specs -- mbp

    # 20061221

    def spec_tree(spec):

        if tree:

            revision = spec.in_store(tree.branch)

        else:

            revision = spec.in_store(None)

        revision_id = revision.rev_id

        branch = revision.branch

        return branch.repository.revision_tree(revision_id)

    if revision_specs is not None:

        assert (old_revision_spec is None

                and new_revision_spec is None)

        if len(revision_specs) > 0:

            old_revision_spec = revision_specs[0]

        if len(revision_specs) > 1:

            new_revision_spec = revision_specs[1]

    if old_revision_spec is None:

        old_tree = tree.basis_tree()

    else:

        old_tree = spec_tree(old_revision_spec)

    if (new_revision_spec is None

        or new_revision_spec.spec is None):

        new_tree = tree

    else:

        new_tree = spec_tree(new_revision_spec)

    if new_tree is not tree:

        extra_trees = (tree,)

    else:

        extra_trees = None

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

                           external_diff_options,

                           old_label=old_label, new_label=new_label,

                           extra_trees=extra_trees)

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

                    external_diff_options=None,

                    old_label='a/', new_label='b/',

                    extra_trees=None,

                    path_encoding='utf8'):

    """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.

    extra_trees

        If set, more Trees to use for looking up file ids

    path_encoding

        If set, the path will be encoded as specified, otherwise is supposed

        to be utf8

    """

    old_tree.lock_read()

    try:

        if extra_trees is not None:

            for tree in extra_trees:

                tree.lock_read()

        new_tree.lock_read()

        try:

            differ = DiffTree.from_trees_options(old_tree, new_tree, to_file,

                                                   path_encoding,

                                                   external_diff_options,

                                                   old_label, new_label)

            return differ.show_diff(specific_files, extra_trees)

        finally:

            new_tree.unlock()

            if extra_trees is not None:

                for tree in extra_trees:

                    tree.unlock()

    finally:

        old_tree.unlock()

def _patch_header_date(tree, file_id, path):

    """Returns a timestamp suitable for use in a patch header."""

    mtime = tree.get_file_mtime(file_id, path)

    assert mtime is not None, \

        "got an mtime of None for file-id %s, path %s in tree %s" % (

                file_id, path, tree)

    return timestamp.format_patch_date(mtime)

def _raise_if_nonexistent(paths, old_tree, new_tree):

    """Complain if paths are not in either inventory or tree.

    It's OK with the files exist in either tree's inventory, or 

    if they exist in the tree but are not versioned.

    This can be used by operations such as bzr status that can accept

    unknown or ignored files.

    """

    mutter("check paths: %r", paths)

    if not paths:

        return

    s = old_tree.filter_unversioned_files(paths)

    s = new_tree.filter_unversioned_files(s)

    s = [path for path in s if not new_tree.has_filename(path)]

    if s:

        raise errors.PathsDoNotExist(sorted(s))

def get_prop_change(meta_modified):

    if meta_modified:

        return " (properties changed)"

    else:

        return  ""

class DiffPath(object):

    """Base type for command object that compare files"""

    # The type or contents of the file were unsuitable for diffing

    CANNOT_DIFF = 'CANNOT_DIFF'

    # The file has changed in a semantic way

    CHANGED = 'CHANGED'

    # The file content may have changed, but there is no semantic change

    UNCHANGED = 'UNCHANGED'

    def __init__(self, old_tree, new_tree, to_file, path_encoding='utf-8'):

        """Constructor.

        :param old_tree: The tree to show as the old tree in the comparison

        :param new_tree: The tree to show as new in the comparison

        :param to_file: The file to write comparison data to

        :param path_encoding: The character encoding to write paths in

        """

        self.old_tree = old_tree

        self.new_tree = new_tree

        self.to_file = to_file

        self.path_encoding = path_encoding

    @classmethod

    def from_diff_tree(klass, diff_tree):

        return klass(diff_tree.old_tree, diff_tree.new_tree,

                     diff_tree.to_file, diff_tree.path_encoding)

    @staticmethod

    def _diff_many(differs, file_id, old_path, new_path, old_kind, new_kind):

        for file_differ in differs:

            result = file_differ.diff(file_id, old_path, new_path, old_kind,

                                      new_kind)

            if result is not DiffPath.CANNOT_DIFF:

                return result

        else:

            return DiffPath.CANNOT_DIFF

class DiffKindChange(object):

    """Special differ for file kind changes.

    Represents kind change as deletion + creation.  Uses the other differs

    to do this.

    """

    def __init__(self, differs):

        self.differs = differs

    @classmethod

    def from_diff_tree(klass, diff_tree):

        return klass(diff_tree.differs)

    def diff(self, file_id, old_path, new_path, old_kind, new_kind):

        """Perform comparison

        :param file_id: The file_id of the file to compare

        :param old_path: Path of the file in the old tree

        :param new_path: Path of the file in the new tree

        :param old_kind: Old file-kind of the file

        :param new_kind: New file-kind of the file

        """

        if None in (old_kind, new_kind):

            return DiffPath.CANNOT_DIFF

        result = DiffPath._diff_many(self.differs, file_id, old_path,

                                       new_path, old_kind, None)

        if result is DiffPath.CANNOT_DIFF:

            return result

        return DiffPath._diff_many(self.differs, file_id, old_path, new_path,

                                     None, new_kind)

class DiffDirectory(DiffPath):

    def diff(self, file_id, old_path, new_path, old_kind, new_kind):

        """Perform comparison between two directories.  (dummy)

        """

        if 'directory' not in (old_kind, new_kind):

            return self.CANNOT_DIFF

        if old_kind not in ('directory', None):

            return self.CANNOT_DIFF

        if new_kind not in ('directory', None):

            return self.CANNOT_DIFF

        return self.CHANGED

class DiffSymlink(DiffPath):

    def diff(self, file_id, old_path, new_path, old_kind, new_kind):

        """Perform comparison between two symlinks

        :param file_id: The file_id of the file to compare

        :param old_path: Path of the file in the old tree

        :param new_path: Path of the file in the new tree

        :param old_kind: Old file-kind of the file

        :param new_kind: New file-kind of the file

        """

        if 'symlink' not in (old_kind, new_kind):

            return self.CANNOT_DIFF

        if old_kind == 'symlink':

            old_target = self.old_tree.get_symlink_target(file_id)

        elif old_kind is None:

            old_target = None

        else:

            return self.CANNOT_DIFF

        if new_kind == 'symlink':

            new_target = self.new_tree.get_symlink_target(file_id)

        elif new_kind is None:

            new_target = None

        else:

            return self.CANNOT_DIFF

        return self.diff_symlink(old_target, new_target)

    def diff_symlink(self, old_target, new_target):

        if old_target is None:

            self.to_file.write('=== target is %r\n' % new_target)

        elif new_target is None:

            self.to_file.write('=== target was %r\n' % old_target)

        else:

            self.to_file.write('=== target changed %r => %r\n' %

                              (old_target, new_target))

        return self.CHANGED

class DiffText(DiffPath):

    # GNU Patch uses the epoch date to detect files that are being added

    # or removed in a diff.

    EPOCH_DATE = '1970-01-01 00:00:00 +0000'

    def __init__(self, old_tree, new_tree, to_file, path_encoding='utf-8',

                 old_label='', new_label='', text_differ=internal_diff):

        DiffPath.__init__(self, old_tree, new_tree, to_file, path_encoding)

        self.text_differ = text_differ

        self.old_label = old_label

        self.new_label = new_label

        self.path_encoding = path_encoding

    def diff(self, file_id, old_path, new_path, old_kind, new_kind):

        """Compare two files in unified diff format

        :param file_id: The file_id of the file to compare

        :param old_path: Path of the file in the old tree

        :param new_path: Path of the file in the new tree

        :param old_kind: Old file-kind of the file

        :param new_kind: New file-kind of the file

        """

        if 'file' not in (old_kind, new_kind):

            return self.CANNOT_DIFF

        from_file_id = to_file_id = file_id

        if old_kind == 'file':

            old_date = _patch_header_date(self.old_tree, file_id, old_path)

        elif old_kind is None:

            old_date = self.EPOCH_DATE

            from_file_id = None

        else:

            return self.CANNOT_DIFF

        if new_kind == 'file':

            new_date = _patch_header_date(self.new_tree, file_id, new_path)

        elif new_kind is None:

            new_date = self.EPOCH_DATE

            to_file_id = None

        else:

            return self.CANNOT_DIFF

        from_label = '%s%s\t%s' % (self.old_label, old_path, old_date)

        to_label = '%s%s\t%s' % (self.new_label, new_path, new_date)

        return self.diff_text(from_file_id, to_file_id, from_label, to_label)

    def diff_text(self, from_file_id, to_file_id, from_label, to_label):

        """Diff the content of given files in two trees

        :param from_file_id: The id of the file in the from tree.  If None,

            the file is not present in the from tree.

        :param to_file_id: The id of the file in the to tree.  This may refer

            to a different file from from_file_id.  If None,

            the file is not present in the to tree.

        """

        def _get_text(tree, file_id):

            if file_id is not None:

                return tree.get_file(file_id).readlines()

            else:

                return []

        try:

            from_text = _get_text(self.old_tree, from_file_id)

            to_text = _get_text(self.new_tree, to_file_id)

            self.text_differ(from_label, from_text, to_label, to_text,

                             self.to_file)

        except errors.BinaryFile:

            self.to_file.write(

                  ("Binary files %s and %s differ\n" %

                  (from_label, to_label)).encode(self.path_encoding))

        return self.CHANGED

class DiffTree(object):

    """Provides textual representations of the difference between two trees.

    A DiffTree examines two trees and where a file-id has altered

    between them, generates a textual representation of the difference.

    DiffTree uses a sequence of DiffPath objects which are each

    given the opportunity to handle a given altered fileid. The list

    of DiffPath objects can be extended globally by appending to

    DiffTree.diff_factories, or for a specific diff operation by

    supplying the extra_factories option to the appropriate method.

    """

    # list of factories that can provide instances of DiffPath objects

    # may be extended by plugins.

    diff_factories = [DiffSymlink.from_diff_tree,

                      DiffDirectory.from_diff_tree]

    def __init__(self, old_tree, new_tree, to_file, path_encoding='utf-8',

                 diff_text=None, extra_factories=None):

        """Constructor

        :param old_tree: Tree to show as old in the comparison

        :param new_tree: Tree to show as new in the comparison

        :param to_file: File to write comparision to

        :param path_encoding: Character encoding to write paths in

        :param diff_text: DiffPath-type object to use as a last resort for

            diffing text files.

        :param extra_factories: Factories of DiffPaths to try before any other

            DiffPaths"""

        if diff_text is None:

            diff_text = DiffText(old_tree, new_tree, to_file, path_encoding,

                                 '', '',  internal_diff)

        self.old_tree = old_tree

        self.new_tree = new_tree

        self.to_file = to_file

        self.path_encoding = path_encoding

        self.differs = []

        if extra_factories is not None:

            self.differs.extend(f(self) for f in extra_factories)

        self.differs.extend(f(self) for f in self.diff_factories)

        self.differs.extend([diff_text, DiffKindChange.from_diff_tree(self)])

    @classmethod

    def from_trees_options(klass, old_tree, new_tree, to_file,

                           path_encoding, external_diff_options, old_label,

                           new_label):

        """Factory for producing a DiffTree.

        Designed to accept options used by show_diff_trees.

        :param old_tree: The tree to show as old in the comparison

        :param new_tree: The tree to show as new in the comparison

        :param to_file: File to write comparisons to

        :param path_encoding: Character encoding to use for writing paths

        :param external_diff_options: If supplied, use the installed diff

            binary to perform file comparison, using supplied options.

        :param old_label: Prefix to use for old file labels

        :param new_label: Prefix to use for new file labels

        """

        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

        diff_text = DiffText(old_tree, new_tree, to_file, path_encoding,

                             old_label, new_label, diff_file)

        return klass(old_tree, new_tree, to_file, path_encoding, diff_text)

    def show_diff(self, specific_files, extra_trees=None):

        """Write tree diff to self.to_file

        :param sepecific_files: the specific files to compare (recursive)

        :param extra_trees: extra trees to use for mapping paths to file_ids

        """

        # TODO: Generation of pseudo-diffs for added/deleted files could

        # be usefully made into a much faster special case.