text: # diff.py
  # Copyright (C) 2008, 2009 Michael Trier (mtrier@gmail.com) and contributors
  #
  # This module is part of GitPython and is released under
  # the BSD License: http://www.opensource.org/licenses/bsd-license.php
  import re
  
  from git.cmd import handle_process_output
  from git.compat import defenc
  from git.util import finalize_process, hex_to_bin
  
  from .objects.blob import Blob
  from .objects.util import mode_str_to_int
  
  
  __all__ = ('Diffable', 'DiffIndex', 'Diff', 'NULL_TREE')
  
  # Special object to compare against the empty tree in diffs
  NULL_TREE = object()
  
  _octal_byte_re = re.compile(b'\\\\([0-9]{3})')
  
  
  def _octal_repl(matchobj):
      value = matchobj.group(1)
      value = int(value, 8)
      value = bytes(bytearray((value,)))
      return value
  
  
  def decode_path(path, has_ab_prefix=True):
      if path == b'/dev/null':
          return None
  
      if path.startswith(b'"') and path.endswith(b'"'):
          path = (path[1:-1].replace(b'\\n', b'\n')
                            .replace(b'\\t', b'\t')
                            .replace(b'\\"', b'"')
                            .replace(b'\\\\', b'\\'))
  
      path = _octal_byte_re.sub(_octal_repl, path)
  
      if has_ab_prefix:
          assert path.startswith(b'a/') or path.startswith(b'b/')
          path = path[2:]
  
      return path
  
  
  class Diffable(object):
  
      """Common interface for all object that can be diffed against another object of compatible type.
  
      :note:
          Subclasses require a repo member as it is the case for Object instances, for practical
          reasons we do not derive from Object."""
      __slots__ = ()
  
      # standin indicating you want to diff against the index
      class Index(object):
          pass
  
      def _process_diff_args(self, args):
          """
          :return:
              possibly altered version of the given args list.
              Method is called right before git command execution.
              Subclasses can use it to alter the behaviour of the superclass"""
          return args
  
      def diff(self, other=Index, paths=None, create_patch=False, **kwargs):
          """Creates diffs between two items being trees, trees and index or an
          index and the working tree. It will detect renames automatically.
  
          :param other:
              Is the item to compare us with.
              If None, we will be compared to the working tree.
              If Treeish, it will be compared against the respective tree
              If Index ( type ), it will be compared against the index.
              If git.NULL_TREE, it will compare against the empty tree.
              It defaults to Index to assure the method will not by-default fail
              on bare repositories.
  
          :param paths:
              is a list of paths or a single path to limit the diff to.
              It will only include at least one of the given path or paths.
  
          :param create_patch:
              If True, the returned Diff contains a detailed patch that if applied
              makes the self to other. Patches are somewhat costly as blobs have to be read
              and diffed.
  
          :param kwargs:
              Additional arguments passed to git-diff, such as
              R=True to swap both sides of the diff.
  
          :return: git.DiffIndex
  
          :note:
              On a bare repository, 'other' needs to be provided as Index or as
              as Tree/Commit, or a git command error will occur"""
          args = []
          args.append("--abbrev=40")        # we need full shas
          args.append("--full-index")       # get full index paths, not only filenames
  
          args.append("-M")                 # check for renames, in both formats
          if create_patch:
              args.append("-p")
          else:
              args.append("--raw")
  
          # in any way, assure we don't see colored output,
          # fixes https://github.com/gitpython-developers/GitPython/issues/172
          args.append('--no-color')
  
          if paths is not None and not isinstance(paths, (tuple, list)):
              paths = [paths]
  
          diff_cmd = self.repo.git.diff
          if other is self.Index:
              args.insert(0, '--cached')
          elif other is NULL_TREE:
              args.insert(0, '-r')  # recursive diff-tree
              args.insert(0, '--root')
              diff_cmd = self.repo.git.diff_tree
          elif other is not None:
              args.insert(0, '-r')  # recursive diff-tree
              args.insert(0, other)
              diff_cmd = self.repo.git.diff_tree
  
          args.insert(0, self)
  
          # paths is list here or None
          if paths:
              args.append("--")
              args.extend(paths)
          # END paths handling
  
          kwargs['as_process'] = True
          proc = diff_cmd(*self._process_diff_args(args), **kwargs)
  
          diff_method = (Diff._index_from_patch_format
                         if create_patch
                         else Diff._index_from_raw_format)
          index = diff_method(self.repo, proc)
  
          proc.wait()
          return index
  
  
  class DiffIndex(list):
  
      """Implements an Index for diffs, allowing a list of Diffs to be queried by
      the diff properties.
  
      The class improves the diff handling convenience"""
      # change type invariant identifying possible ways a blob can have changed
      # A = Added
      # D = Deleted
      # R = Renamed
      # M = Modified
      # T = Changed in the type
      change_type = ("A", "C", "D", "R", "M", "T")
  
      def iter_change_type(self, change_type):
          """
          :return:
              iterator yielding Diff instances that match the given change_type
  
          :param change_type:
              Member of DiffIndex.change_type, namely:
  
              * 'A' for added paths
              * 'D' for deleted paths
              * 'R' for renamed paths
              * 'M' for paths with modified data
              * 'T' for changed in the type paths
           """
          if change_type not in self.change_type:
              raise ValueError("Invalid change type: %s" % change_type)
  
          for diff in self:
              if diff.change_type == change_type:
                  yield diff
              elif change_type == "A" and diff.new_file:
                  yield diff
              elif change_type == "D" and diff.deleted_file:
                  yield diff
              elif change_type == "C" and diff.copied_file:
                  yield diff
              elif change_type == "R" and diff.renamed:
                  yield diff
              elif change_type == "M" and diff.a_blob and diff.b_blob and diff.a_blob != diff.b_blob:
                  yield diff
          # END for each diff
  
  
  class Diff(object):
  
      """A Diff contains diff information between two Trees.
  
      It contains two sides a and b of the diff, members are prefixed with
      "a" and "b" respectively to inidcate that.
  
      Diffs keep information about the changed blob objects, the file mode, renames,
      deletions and new files.
  
      There are a few cases where None has to be expected as member variable value:
  
      ``New File``::
  
          a_mode is None
          a_blob is None
          a_path is None
  
      ``Deleted File``::
  
          b_mode is None
          b_blob is None
          b_path is None
  
      ``Working Tree Blobs``
  
          When comparing to working trees, the working tree blob will have a null hexsha
          as a corresponding object does not yet exist. The mode will be null as well.
          But the path will be available though.
          If it is listed in a diff the working tree version of the file must
          be different to the version in the index or tree, and hence has been modified."""
  
      # precompiled regex
      re_header = re.compile(br"""
                                  ^diff[ ]--git
                                      [ ](?P<a_path_fallback>"?[ab]/.+?"?)[ ](?P<b_path_fallback>"?[ab]/.+?"?)\n
                                  (?:^old[ ]mode[ ](?P<old_mode>\d+)\n
                                     ^new[ ]mode[ ](?P<new_mode>\d+)(?:\n|$))?
                                  (?:^similarity[ ]index[ ]\d+%\n
                                     ^rename[ ]from[ ](?P<rename_from>.*)\n
                                     ^rename[ ]to[ ](?P<rename_to>.*)(?:\n|$))?
                                  (?:^new[ ]file[ ]mode[ ](?P<new_file_mode>.+)(?:\n|$))?
                                  (?:^deleted[ ]file[ ]mode[ ](?P<deleted_file_mode>.+)(?:\n|$))?
                                  (?:^similarity[ ]index[ ]\d+%\n
                                     ^copy[ ]from[ ].*\n
                                     ^copy[ ]to[ ](?P<copied_file_name>.*)(?:\n|$))?
                                  (?:^index[ ](?P<a_blob_id>[0-9A-Fa-f]+)
                                      \.\.(?P<b_blob_id>[0-9A-Fa-f]+)[ ]?(?P<b_mode>.+)?(?:\n|$))?
                                  (?:^---[ ](?P<a_path>[^\t\n\r\f\v]*)[\t\r\f\v]*(?:\n|$))?
                                  (?:^\+\+\+[ ](?P<b_path>[^\t\n\r\f\v]*)[\t\r\f\v]*(?:\n|$))?
                              """, re.VERBOSE | re.MULTILINE)
      # can be used for comparisons
      NULL_HEX_SHA = "0" * 40
      NULL_BIN_SHA = b"\0" * 20
  
      __slots__ = ("a_blob", "b_blob", "a_mode", "b_mode", "a_rawpath", "b_rawpath",
                   "new_file", "deleted_file", "copied_file", "raw_rename_from",
                   "raw_rename_to", "diff", "change_type", "score")
  
      def __init__(self, repo, a_rawpath, b_rawpath, a_blob_id, b_blob_id, a_mode,
                   b_mode, new_file, deleted_file, copied_file, raw_rename_from,
                   raw_rename_to, diff, change_type, score):
  
          self.a_mode = a_mode
          self.b_mode = b_mode
  
          assert a_rawpath is None or isinstance(a_rawpath, bytes)
          assert b_rawpath is None or isinstance(b_rawpath, bytes)
          self.a_rawpath = a_rawpath
          self.b_rawpath = b_rawpath
  
          if self.a_mode:
              self.a_mode = mode_str_to_int(self.a_mode)
          if self.b_mode:
              self.b_mode = mode_str_to_int(self.b_mode)
  
          # Determine whether this diff references a submodule, if it does then
          # we need to overwrite "repo" to the corresponding submodule's repo instead
          if repo and a_rawpath:
              for submodule in repo.submodules:
                  if submodule.path == a_rawpath.decode("utf-8"):
                      if submodule.module_exists():
                          repo = submodule.module()
                      break
  
          if a_blob_id is None or a_blob_id == self.NULL_HEX_SHA:
              self.a_blob = None
          else:
              self.a_blob = Blob(repo, hex_to_bin(a_blob_id), mode=self.a_mode, path=self.a_path)
  
          if b_blob_id is None or b_blob_id == self.NULL_HEX_SHA:
              self.b_blob = None
          else:
              self.b_blob = Blob(repo, hex_to_bin(b_blob_id), mode=self.b_mode, path=self.b_path)
  
          self.new_file = new_file
          self.deleted_file = deleted_file
          self.copied_file = copied_file
  
          # be clear and use None instead of empty strings
          assert raw_rename_from is None or isinstance(raw_rename_from, bytes)
          assert raw_rename_to is None or isinstance(raw_rename_to, bytes)
          self.raw_rename_from = raw_rename_from or None
          self.raw_rename_to = raw_rename_to or None
  
          self.diff = diff
          self.change_type = change_type
          self.score = score
  
      def __eq__(self, other):
          for name in self.__slots__:
              if getattr(self, name) != getattr(other, name):
                  return False
          # END for each name
          return True
  
      def __ne__(self, other):
          return not (self == other)
  
      def __hash__(self):
          return hash(tuple(getattr(self, n) for n in self.__slots__))
  
      def __str__(self):
          h = "%s"
          if self.a_blob:
              h %= self.a_blob.path
          elif self.b_blob:
              h %= self.b_blob.path
  
          msg = ''
          line = None          # temp line
          line_length = 0      # line length
          for b, n in zip((self.a_blob, self.b_blob), ('lhs', 'rhs')):
              if b:
                  line = "\n%s: %o | %s" % (n, b.mode, b.hexsha)
              else:
                  line = "\n%s: None" % n
              # END if blob is not None
              line_length = max(len(line), line_length)
              msg += line
          # END for each blob
  
          # add headline
          h += '\n' + '=' * line_length
  
          if self.deleted_file:
              msg += '\nfile deleted in rhs'
          if self.new_file:
              msg += '\nfile added in rhs'
          if self.copied_file:
              msg += '\nfile %r copied from %r' % (self.b_path, self.a_path)
          if self.rename_from:
              msg += '\nfile renamed from %r' % self.rename_from
          if self.rename_to:
              msg += '\nfile renamed to %r' % self.rename_to
          if self.diff:
              msg += '\n---'
              try:
                  msg += self.diff.decode(defenc)
              except UnicodeDecodeError:
                  msg += 'OMITTED BINARY DATA'
              # end handle encoding
              msg += '\n---'
          # END diff info
  
          # Python2 silliness: have to assure we convert our likely to be unicode object to a string with the
          # right encoding. Otherwise it tries to convert it using ascii, which may fail ungracefully
          res = h + msg
          # end
          return res
  
      @property
      def a_path(self):
          return self.a_rawpath.decode(defenc, 'replace') if self.a_rawpath else None
  
      @property
      def b_path(self):
          return self.b_rawpath.decode(defenc, 'replace') if self.b_rawpath else None
  
      @property
      def rename_from(self):
          return self.raw_rename_from.decode(defenc, 'replace') if self.raw_rename_from else None
  
      @property
      def rename_to(self):
          return self.raw_rename_to.decode(defenc, 'replace') if self.raw_rename_to else None
  
      @property
      def renamed(self):
          """:returns: True if the blob of our diff has been renamed
          :note: This property is deprecated, please use ``renamed_file`` instead.
          """
          return self.renamed_file
  
      @property
      def renamed_file(self):
          """:returns: True if the blob of our diff has been renamed
          """
          return self.rename_from != self.rename_to
  
      @classmethod
      def _pick_best_path(cls, path_match, rename_match, path_fallback_match):
          if path_match:
              return decode_path(path_match)
  
          if rename_match:
              return decode_path(rename_match, has_ab_prefix=False)
  
          if path_fallback_match:
              return decode_path(path_fallback_match)
  
          return None
  
      @classmethod
      def _index_from_patch_format(cls, repo, proc):
          """Create a new DiffIndex from the given text which must be in patch format
          :param repo: is the repository we are operating on - it is required
          :param stream: result of 'git diff' as a stream (supporting file protocol)
          :return: git.DiffIndex """
  
          ## FIXME: Here SLURPING raw, need to re-phrase header-regexes linewise.
          text = []
          handle_process_output(proc, text.append, None, finalize_process, decode_streams=False)
  
          # for now, we have to bake the stream
          text = b''.join(text)
          index = DiffIndex()
          previous_header = None
          header = None
          for _header in cls.re_header.finditer(text):
              a_path_fallback, b_path_fallback, \
                  old_mode, new_mode, \
                  rename_from, rename_to, \
                  new_file_mode, deleted_file_mode, copied_file_name, \
                  a_blob_id, b_blob_id, b_mode, \
                  a_path, b_path = _header.groups()
  
              new_file, deleted_file, copied_file = \
                  bool(new_file_mode), bool(deleted_file_mode), bool(copied_file_name)
  
              a_path = cls._pick_best_path(a_path, rename_from, a_path_fallback)
              b_path = cls._pick_best_path(b_path, rename_to, b_path_fallback)
  
              # Our only means to find the actual text is to see what has not been matched by our regex,
              # and then retro-actively assign it to our index
              if previous_header is not None:
                  index[-1].diff = text[previous_header.end():_header.start()]
              # end assign actual diff
  
              # Make sure the mode is set if the path is set. Otherwise the resulting blob is invalid
              # We just use the one mode we should have parsed
              a_mode = old_mode or deleted_file_mode or (a_path and (b_mode or new_mode or new_file_mode))
              b_mode = b_mode or new_mode or new_file_mode or (b_path and a_mode)
              index.append(Diff(repo,
                                a_path,
                                b_path,
                                a_blob_id and a_blob_id.decode(defenc),
                                b_blob_id and b_blob_id.decode(defenc),
                                a_mode and a_mode.decode(defenc),
                                b_mode and b_mode.decode(defenc),
                                new_file, deleted_file, copied_file,
                                rename_from,
                                rename_to,
                                None, None, None))
  
              previous_header = _header
              header = _header
          # end for each header we parse
          if index:
              index[-1].diff = text[header.end():]
          # end assign last diff
  
          return index
  
      @classmethod
      def _index_from_raw_format(cls, repo, proc):
          """Create a new DiffIndex from the given stream which must be in raw format.
          :return: git.DiffIndex"""
          # handles
          # :100644 100644 687099101... 37c5e30c8... M    .gitignore
  
          index = DiffIndex()
  
          def handle_diff_line(line):
              line = line.decode(defenc)
              if not line.startswith(":"):
                  return
  
              meta, _, path = line[1:].partition('\t')
              old_mode, new_mode, a_blob_id, b_blob_id, _change_type = meta.split(None, 4)
              # Change type can be R100
              # R: status letter
              # 100: score (in case of copy and rename)
              change_type = _change_type[0]
              score_str = ''.join(_change_type[1:])
              score = int(score_str) if score_str.isdigit() else None
              path = path.strip()
              a_path = path.encode(defenc)
              b_path = path.encode(defenc)
              deleted_file = False
              new_file = False
              copied_file = False
              rename_from = None
              rename_to = None
  
              # NOTE: We cannot conclude from the existence of a blob to change type
              # as diffs with the working do not have blobs yet
              if change_type == 'D':
                  b_blob_id = None
                  deleted_file = True
              elif change_type == 'A':
                  a_blob_id = None
                  new_file = True
              elif change_type == 'C':
                  copied_file = True
                  a_path, b_path = path.split('\t', 1)
                  a_path = a_path.encode(defenc)
                  b_path = b_path.encode(defenc)
              elif change_type == 'R':
                  a_path, b_path = path.split('\t', 1)
                  a_path = a_path.encode(defenc)
                  b_path = b_path.encode(defenc)
                  rename_from, rename_to = a_path, b_path
              elif change_type == 'T':
                  # Nothing to do
                  pass
              # END add/remove handling
  
              diff = Diff(repo, a_path, b_path, a_blob_id, b_blob_id, old_mode, new_mode,
                          new_file, deleted_file, copied_file, rename_from, rename_to,
                          '', change_type, score)
              index.append(diff)
  
          handle_process_output(proc, handle_diff_line, None, finalize_process, decode_streams=False)
  
          return index
  