text: # index.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 tempfile
  import os
  import sys
  import subprocess
  import glob
  from cStringIO import StringIO
  
  from stat import S_ISLNK
  
  from typ import (
                      BaseIndexEntry, 
                      IndexEntry, 
                  )
  
  from util import (
                      TemporaryFileSwap,
                      post_clear_cache, 
                      default_index,
                      git_working_dir
                  )
  
  import git.objects
  import git.diff as diff
  
  from git.exc import (
                              GitCommandError,
                              CheckoutError
                          )
  
  from git.objects import (
                              Blob,
                              Submodule,
                              Tree, 
                              Object, 
                              Commit,
                          )
  
  from git.objects.util import Serializable
  
  from git.util import (
                              IndexFileSHA1Writer, 
                              LazyMixin, 
                              LockedFD, 
                              join_path_native, 
                              file_contents_ro,
                              to_native_path_linux,
                              to_native_path
                          )
  
  from fun import (
                      entry_key,
                      write_cache,
                      read_cache,
                      aggressive_tree_merge,
                      write_tree_from_cache,
                      stat_mode_to_index_mode, 
                      S_IFGITLINK
                  )
  
  from gitdb.base import IStream
  from gitdb.db import MemoryDB
  from gitdb.util import to_bin_sha
  from itertools import izip
  
  __all__ = ( 'IndexFile', 'CheckoutError' )
  
  
  class IndexFile(LazyMixin, diff.Diffable, Serializable):
      """
      Implements an Index that can be manipulated using a native implementation in
      order to save git command function calls wherever possible.
      
      It provides custom merging facilities allowing to merge without actually changing
      your index or your working tree. This way you can perform own test-merges based
      on the index only without having to deal with the working copy. This is useful
      in case of partial working trees.
  
      ``Entries``
      
      The index contains an entries dict whose keys are tuples of type IndexEntry
      to facilitate access.
  
      You may read the entries dict or manipulate it using IndexEntry instance, i.e.::
      
          index.entries[index.entry_key(index_entry_instance)] = index_entry_instance
      
      Make sure you use index.write() once you are done manipulating the index directly
      before operating on it using the git command"""
      __slots__ = ("repo", "version", "entries", "_extension_data", "_file_path")
      _VERSION = 2            # latest version we support
      S_IFGITLINK = S_IFGITLINK # a submodule
  
      def __init__(self, repo, file_path=None):
          """Initialize this Index instance, optionally from the given ``file_path``.
          If no file_path is given, we will be created from the current index file.
  
          If a stream is not given, the stream will be initialized from the current
          repository's index on demand."""
          self.repo = repo
          self.version = self._VERSION
          self._extension_data = ''
          self._file_path = file_path or self._index_path()
  
      def _set_cache_(self, attr):
          if attr == "entries":
              # read the current index
              # try memory map for speed
              lfd = LockedFD(self._file_path)
              try:
                  fd = lfd.open(write=False, stream=False)
              except OSError:
                  lfd.rollback()
                  # in new repositories, there may be no index, which means we are empty
                  self.entries = dict()
                  return
              # END exception handling
  
              # Here it comes: on windows in python 2.5, memory maps aren't closed properly 
              # Hence we are in trouble if we try to delete a file that is memory mapped, 
              # which happens during read-tree.
              # In this case, we will just read the memory in directly.
              # Its insanely bad ... I am disappointed !
              allow_mmap = (os.name != 'nt' or sys.version_info[1] > 5)  
              stream = file_contents_ro(fd, stream=True, allow_mmap=allow_mmap)
              
              try:
                  self._deserialize(stream)
              finally:
                  lfd.rollback()
                  # The handles will be closed on desctruction
              # END read from default index on demand
          else:
              super(IndexFile, self)._set_cache_(attr)
  
      def _index_path(self):
          return join_path_native(self.repo.git_dir, "index")
  
      @property
      def path(self):
          """ :return: Path to the index file we are representing """
          return self._file_path
  
      def _delete_entries_cache(self):
          """Safely clear the entries cache so it can be recreated"""
          try:
              del(self.entries)
          except AttributeError:
              # fails in python 2.6.5 with this exception
              pass
          # END exception handling
  
      #{ Serializable Interface 
  
      def _deserialize(self, stream):
          """Initialize this instance with index values read from the given stream"""
          self.version, self.entries, self._extension_data, conten_sha = read_cache(stream)
          return self
          
      def _entries_sorted(self):
          """:return: list of entries, in a sorted fashion, first by path, then by stage"""
          entries_sorted = self.entries.values()
          entries_sorted.sort(key=lambda e: (e.path, e.stage))        # use path/stage as sort key
          return entries_sorted
          
      def _serialize(self, stream, ignore_tree_extension_data=False):
          entries = self._entries_sorted()
          write_cache(entries,
                      stream,
                      (ignore_tree_extension_data and None) or self._extension_data) 
          return self
          
          
      #} END serializable interface
  
      def write(self, file_path = None, ignore_tree_extension_data=False):
          """Write the current state to our file path or to the given one
  
          :param file_path:
              If None, we will write to our stored file path from which we have
              been initialized. Otherwise we write to the given file path.
              Please note that this will change the file_path of this index to
              the one you gave.
  
          :param ignore_tree_extension_data:
              If True, the TREE type extension data read in the index will not
              be written to disk. Use this if you have altered the index and
              would like to use git-write-tree afterwards to create a tree
              representing your written changes.
              If this data is present in the written index, git-write-tree
              will instead write the stored/cached tree.
              Alternatively, use IndexFile.write_tree() to handle this case
              automatically
  
          :return: self"""
          # make sure we have our entries read before getting a write lock
          # else it would be done when streaming. This can happen 
          # if one doesn't change the index, but writes it right away
          self.entries
          lfd = LockedFD(file_path or self._file_path)
          stream = lfd.open(write=True, stream=True)
          
          self._serialize(stream, ignore_tree_extension_data)
          
          lfd.commit()
  
          # make sure we represent what we have written
          if file_path is not None:
              self._file_path = file_path
  
      @post_clear_cache
      @default_index
      def merge_tree(self, rhs, base=None):
          """Merge the given rhs treeish into the current index, possibly taking
          a common base treeish into account.
  
          As opposed to the from_tree_ method, this allows you to use an already
          existing tree as the left side of the merge
  
          :param rhs:
              treeish reference pointing to the 'other' side of the merge.
  
          :param base:
              optional treeish reference pointing to the common base of 'rhs' and
              this index which equals lhs
  
          :return:
              self ( containing the merge and possibly unmerged entries in case of
              conflicts )
  
          :raise GitCommandError:
              If there is a merge conflict. The error will
              be raised at the first conflicting path. If you want to have proper
              merge resolution to be done by yourself, you have to commit the changed
              index ( or make a valid tree from it ) and retry with a three-way
              index.from_tree call. """
          # -i : ignore working tree status
          # --aggressive : handle more merge cases
          # -m : do an actual merge
          args = ["--aggressive", "-i", "-m"]
          if base is not None:
              args.append(base)
          args.append(rhs)
  
          self.repo.git.read_tree(args)
          return self
  
      @classmethod
      def new(cls, repo, *tree_sha):
          """ Merge the given treeish revisions into a new index which is returned.
          This method behaves like git-read-tree --aggressive when doing the merge.
  
          :param repo: The repository treeish are located in.
  
          :param tree_sha:
              20 byte or 40 byte tree sha or tree objects 
  
          :return:
              New IndexFile instance. Its path will be undefined. 
              If you intend to write such a merged Index, supply an alternate file_path 
              to its 'write' method."""
          base_entries = aggressive_tree_merge(repo.odb, [to_bin_sha(str(t)) for t in tree_sha])
          
          inst = cls(repo)
          # convert to entries dict
          entries = dict(izip(((e.path, e.stage) for e in base_entries), 
                              (IndexEntry.from_base(e) for e in base_entries)))
          
          inst.entries = entries
          return inst
  
  
      @classmethod
      def from_tree(cls, repo, *treeish, **kwargs):
          """Merge the given treeish revisions into a new index which is returned.
          The original index will remain unaltered
  
          :param repo:
              The repository treeish are located in.
  
          :param treeish:
              One, two or three Tree Objects, Commits or 40 byte hexshas. The result
              changes according to the amount of trees.
              If 1 Tree is given, it will just be read into a new index
              If 2 Trees are given, they will be merged into a new index using a
               two way merge algorithm. Tree 1 is the 'current' tree, tree 2 is the 'other'
               one. It behaves like a fast-forward.
               If 3 Trees are given, a 3-way merge will be performed with the first tree
               being the common ancestor of tree 2 and tree 3. Tree 2 is the 'current' tree,
               tree 3 is the 'other' one
  
          :param kwargs:
              Additional arguments passed to git-read-tree
  
          :return:
              New IndexFile instance. It will point to a temporary index location which
              does not exist anymore. If you intend to write such a merged Index, supply
              an alternate file_path to its 'write' method.
  
          :note:
              In the three-way merge case, --aggressive will be specified to automatically
              resolve more cases in a commonly correct manner. Specify trivial=True as kwarg
              to override that.
  
              As the underlying git-read-tree command takes into account the current index,
              it will be temporarily moved out of the way to assure there are no unsuspected
              interferences."""
          if len(treeish) == 0 or len(treeish) > 3:
              raise ValueError("Please specify between 1 and 3 treeish, got %i" % len(treeish))
  
          arg_list = list()
          # ignore that working tree and index possibly are out of date
          if len(treeish)>1:
              # drop unmerged entries when reading our index and merging
              arg_list.append("--reset")
              # handle non-trivial cases the way a real merge does
              arg_list.append("--aggressive")
          # END merge handling
  
          # tmp file created in git home directory to be sure renaming
          # works - /tmp/ dirs could be on another device
          tmp_index = tempfile.mktemp('','',repo.git_dir)
          arg_list.append("--index-output=%s" % tmp_index)
          arg_list.extend(treeish)
  
          # move current index out of the way - otherwise the merge may fail
          # as it considers existing entries. moving it essentially clears the index.
          # Unfortunately there is no 'soft' way to do it.
          # The TemporaryFileSwap assure the original file get put back
          index_handler = TemporaryFileSwap(join_path_native(repo.git_dir, 'index'))
          try:
              repo.git.read_tree(*arg_list, **kwargs)
              index = cls(repo, tmp_index)
              index.entries       # force it to read the file as we will delete the temp-file
              del(index_handler)  # release as soon as possible
          finally:
              if os.path.exists(tmp_index):
                  os.remove(tmp_index)
          # END index merge handling
  
          return index
  
      # UTILITIES
      def _iter_expand_paths(self, paths):
          """Expand the directories in list of paths to the corresponding paths accordingly,
  
          Note: git will add items multiple times even if a glob overlapped
          with manually specified paths or if paths where specified multiple
          times - we respect that and do not prune"""
          def raise_exc(e):
              raise e
          r = self.repo.working_tree_dir
          rs = r + os.sep
          for path in paths:
              abs_path = path
              if not os.path.isabs(abs_path):
                  abs_path = os.path.join(r, path)
              # END make absolute path
  
              # resolve globs if possible
              if '?' in path or '*' in path or '[' in path:
                  for f in self._iter_expand_paths(glob.glob(abs_path)):
                      yield f.replace(rs, '')
                  continue
              # END glob handling
              try:
                  for root, dirs, files in os.walk(abs_path, onerror=raise_exc):
                      for rela_file in files:
                          # add relative paths only
                          yield os.path.join(root.replace(rs, ''), rela_file)
                      # END for each file in subdir
                  # END for each subdirectory
              except OSError:
                  # was a file or something that could not be iterated
                  yield path.replace(rs, '')
              # END path exception handling
          # END for each path
  
      def _write_path_to_stdin(self, proc, filepath, item, fmakeexc, fprogress, 
                                  read_from_stdout=True):
          """Write path to proc.stdin and make sure it processes the item, including progress.
  
          :return: stdout string
          :param read_from_stdout: if True, proc.stdout will be read after the item
              was sent to stdin. In that case, it will return None
          :note: There is a bug in git-update-index that prevents it from sending
              reports just in time. This is why we have a version that tries to
              read stdout and one which doesn't. In fact, the stdout is not
              important as the piped-in files are processed anyway and just in time
          :note: Newlines are essential here, gits behaviour is somewhat inconsistent
              on this depending on the version, hence we try our best to deal with
              newlines carefully. Usually the last newline will not be sent, instead
              we will close stdin to break the pipe."""
  
          fprogress(filepath, False, item)
          rval = None
          try:
              proc.stdin.write("%s\n" % filepath)
          except IOError:
              # pipe broke, usually because some error happend
              raise fmakeexc()
          # END write exception handling
          proc.stdin.flush()
          if read_from_stdout:
              rval = proc.stdout.readline().strip()
          fprogress(filepath, True, item)
          return rval
  
      def iter_blobs(self, predicate = lambda t: True):
          """
          :return: Iterator yielding tuples of Blob objects and stages, tuple(stage, Blob)
  
          :param predicate:
              Function(t) returning True if tuple(stage, Blob) should be yielded by the
              iterator. A default filter, the BlobFilter, allows you to yield blobs
              only if they match a given list of paths. """
          for entry in self.entries.itervalues():
              # TODO: is it necessary to convert the mode ? We did that when adding 
              # it to the index, right ?
              mode = stat_mode_to_index_mode(entry.mode)
              blob = entry.to_blob(self.repo)
              blob.size = entry.size
              output = (entry.stage, blob)
              if predicate(output):
                  yield output
          # END for each entry
  
      def unmerged_blobs(self):
          """
          :return:
              Iterator yielding dict(path : list( tuple( stage, Blob, ...))), being
              a dictionary associating a path in the index with a list containing
              sorted stage/blob pairs
  
          :note:
              Blobs that have been removed in one side simply do not exist in the
              given stage. I.e. a file removed on the 'other' branch whose entries
              are at stage 3 will not have a stage 3 entry.
          """
          is_unmerged_blob = lambda t: t[0] != 0
          path_map = dict()
          for stage, blob in self.iter_blobs(is_unmerged_blob):
              path_map.setdefault(blob.path, list()).append((stage, blob))
          # END for each unmerged blob
          for l in path_map.itervalues():
              l.sort()
          return path_map
  
      @classmethod
      def entry_key(cls, *entry):
          return entry_key(*entry)
  
      def resolve_blobs(self, iter_blobs):
          """Resolve the blobs given in blob iterator. This will effectively remove the
          index entries of the respective path at all non-null stages and add the given
          blob as new stage null blob.
  
          For each path there may only be one blob, otherwise a ValueError will be raised
          claiming the path is already at stage 0.
  
          :raise ValueError: if one of the blobs already existed at stage 0
          :return: self
  
          :note:
              You will have to write the index manually once you are done, i.e.
              index.resolve_blobs(blobs).write()
          """
          for blob in iter_blobs:
              stage_null_key = (blob.path, 0)
              if stage_null_key in self.entries:
                  raise ValueError( "Path %r already exists at stage 0" % blob.path )
              # END assert blob is not stage 0 already
  
              # delete all possible stages
              for stage in (1, 2, 3):
                  try:
                      del( self.entries[(blob.path, stage)])
                  except KeyError:
                      pass
                  # END ignore key errors
              # END for each possible stage
  
              self.entries[stage_null_key] = IndexEntry.from_blob(blob)
          # END for each blob
  
          return self
  
      def update(self):
          """Reread the contents of our index file, discarding all cached information
          we might have.
  
          :note: This is a possibly dangerious operations as it will discard your changes
              to index.entries
          :return: self"""
          self._delete_entries_cache()
          # allows to lazily reread on demand
          return self
  
      def write_tree(self):
          """Writes this index to a corresponding Tree object into the repository's
          object database and return it.
          
          :return: Tree object representing this index
          :note: The tree will be written even if one or more objects the tree refers to 
              does not yet exist in the object database. This could happen if you added
              Entries to the index directly.
          :raise ValueError: if there are no entries in the cache
          :raise UnmergedEntriesError: """
          # we obtain no lock as we just flush our contents to disk as tree
          # If we are a new index, the entries access will load our data accordingly
          mdb = MemoryDB()
          entries = self._entries_sorted()
          binsha, tree_items = write_tree_from_cache(entries, mdb, slice(0, len(entries)))
          
          # copy changed trees only
          mdb.stream_copy(mdb.sha_iter(), self.repo.odb)
          
          
          # note: additional deserialization could be saved if write_tree_from_cache
          # would return sorted tree entries
          root_tree = Tree(self.repo, binsha, path='')
          root_tree._cache = tree_items
          return root_tree
          
      def _process_diff_args(self, args):
          try:
              args.pop(args.index(self))
          except IndexError:
              pass
          # END remove self
          return args
  
      def _to_relative_path(self, path):
          """:return: Version of path relative to our git directory or raise ValueError
          if it is not within our git direcotory"""
          if not os.path.isabs(path):
              return path
          relative_path = path.replace(self.repo.working_tree_dir+os.sep, "")
          if relative_path == path:
              raise ValueError("Absolute path %r is not in git repository at %r" % (path,self.repo.working_tree_dir))
          return relative_path
  
      def _preprocess_add_items(self, items):
          """ Split the items into two lists of path strings and BaseEntries. """
          paths = list()
          entries = list()
  
          for item in items:
              if isinstance(item, basestring):
                  paths.append(self._to_relative_path(item))
              elif isinstance(item, (Blob, Submodule)):
                  entries.append(BaseIndexEntry.from_blob(item))
              elif isinstance(item, BaseIndexEntry):
                  entries.append(item)
              else:
                  raise TypeError("Invalid Type: %r" % item)
          # END for each item
          return (paths, entries)
  
      @git_working_dir
      def add(self, items, force=True, fprogress=lambda *args: None, path_rewriter=None, 
                  write=True):
          """Add files from the working tree, specific blobs or BaseIndexEntries
          to the index. 
  
          :param items:
              Multiple types of items are supported, types can be mixed within one call.
              Different types imply a different handling. File paths may generally be
              relative or absolute.
  
              - path string
                  strings denote a relative or absolute path into the repository pointing to
                  an existing file, i.e. CHANGES, lib/myfile.ext, '/home/gitrepo/lib/myfile.ext'.
  
                  Paths provided like this must exist. When added, they will be written
                  into the object database.
  
                  PathStrings may contain globs, such as 'lib/__init__*' or can be directories
                  like 'lib', the latter ones will add all the files within the dirctory and
                  subdirectories.
  
                  This equals a straight git-add.
  
                  They are added at stage 0
  
              - Blob or Submodule object
                  Blobs are added as they are assuming a valid mode is set.
                  The file they refer to may or may not exist in the file system, but
                  must be a path relative to our repository.
  
                  If their sha is null ( 40*0 ), their path must exist in the file system
                  relative to the git repository as an object will be created from 
                  the data at the path.
                  The handling now very much equals the way string paths are processed, except that
                  the mode you have set will be kept. This allows you to create symlinks
                  by settings the mode respectively and writing the target of the symlink
                  directly into the file. This equals a default Linux-Symlink which
                  is not dereferenced automatically, except that it can be created on
                  filesystems not supporting it as well.
  
                  Please note that globs or directories are not allowed in Blob objects.
  
                  They are added at stage 0
  
              - BaseIndexEntry or type
                  Handling equals the one of Blob objects, but the stage may be
                  explicitly set. Please note that Index Entries require binary sha's.
  
          :param force:
              **CURRENTLY INEFFECTIVE**
              If True, otherwise ignored or excluded files will be
              added anyway.
              As opposed to the git-add command, we enable this flag by default
              as the API user usually wants the item to be added even though
              they might be excluded.
  
          :param fprogress:
              Function with signature f(path, done=False, item=item) called for each
              path to be added, one time once it is about to be added where done==False
              and once after it was added where done=True.
              item is set to the actual item we handle, either a Path or a BaseIndexEntry
              Please note that the processed path is not guaranteed to be present
              in the index already as the index is currently being processed.
  
          :param path_rewriter:
              Function with signature (string) func(BaseIndexEntry) function returning a path
              for each passed entry which is the path to be actually recorded for the
              object created from entry.path. This allows you to write an index which
              is not identical to the layout of the actual files on your hard-disk.
              If not None and ``items`` contain plain paths, these paths will be
              converted to Entries beforehand and passed to the path_rewriter.
              Please note that entry.path is relative to the git repository.
  
          :param write:
                  If True, the index will be written once it was altered. Otherwise
                  the changes only exist in memory and are not available to git commands.
          
          :return:
              List(BaseIndexEntries) representing the entries just actually added.
  
          :raise OSError:
              if a supplied Path did not exist. Please note that BaseIndexEntry
              Objects that do not have a null sha will be added even if their paths
              do not exist.
          """
          # sort the entries into strings and Entries, Blobs are converted to entries
          # automatically
          # paths can be git-added, for everything else we use git-update-index
          entries_added = list()
          paths, entries = self._preprocess_add_items(items)
          if paths and path_rewriter:
              for path in paths:
                  abspath = os.path.abspath(path)
                  gitrelative_path = abspath[len(self.repo.working_tree_dir)+1:]
                  blob = Blob(self.repo, Blob.NULL_BIN_SHA, 
                              stat_mode_to_index_mode(os.stat(abspath).st_mode), 
                              to_native_path_linux(gitrelative_path))
                  entries.append(BaseIndexEntry.from_blob(blob))
              # END for each path
              del(paths[:])
          # END rewrite paths
  
  
          def store_path(filepath):
              """Store file at filepath in the database and return the base index entry"""
              st = os.lstat(filepath)     # handles non-symlinks as well
              stream = None
              if S_ISLNK(st.st_mode):
                  stream = StringIO(os.readlink(filepath))
              else:
                  stream = open(filepath, 'rb')
              # END handle stream
              fprogress(filepath, False, filepath)
              istream = self.repo.odb.store(IStream(Blob.type, st.st_size, stream))
              fprogress(filepath, True, filepath)
              return BaseIndexEntry((stat_mode_to_index_mode(st.st_mode), 
                                      istream.binsha, 0, to_native_path_linux(filepath)))
          # END utility method
  
  
          # HANDLE PATHS
          if paths:
              assert len(entries_added) == 0
              added_files = list()
              for filepath in self._iter_expand_paths(paths):
                  entries_added.append(store_path(filepath))
              # END for each filepath
          # END path handling
  
  
          # HANDLE ENTRIES
          if entries:
              null_mode_entries = [ e for e in entries if e.mode == 0 ]
              if null_mode_entries:
                  raise ValueError("At least one Entry has a null-mode - please use index.remove to remove files for clarity")
              # END null mode should be remove
  
              # HANLDE ENTRY OBJECT CREATION
              # create objects if required, otherwise go with the existing shas
              null_entries_indices = [ i for i,e in enumerate(entries) if e.binsha == Object.NULL_BIN_SHA ]
              if null_entries_indices:
                  for ei in null_entries_indices:
                      null_entry = entries[ei]
                      new_entry = store_path(null_entry.path)
                      
                      # update null entry
                      entries[ei] = BaseIndexEntry((null_entry.mode, new_entry.binsha, null_entry.stage, null_entry.path))
                  # END for each entry index
              # END null_entry handling
  
              # REWRITE PATHS
              # If we have to rewrite the entries, do so now, after we have generated
              # all object sha's
              if path_rewriter:
                  for i,e in enumerate(entries):
                      entries[i] = BaseIndexEntry((e.mode, e.binsha, e.stage, path_rewriter(e)))
                  # END for each entry
              # END handle path rewriting
  
              # just go through the remaining entries and provide progress info
              for i, entry in enumerate(entries):
                  progress_sent = i in null_entries_indices
                  if not progress_sent:
                      fprogress(entry.path, False, entry)
                      fprogress(entry.path, True, entry)
                  # END handle progress
              # END for each enty
              entries_added.extend(entries)
          # END if there are base entries
  
          # FINALIZE
          # add the new entries to this instance
          for entry in entries_added:
              self.entries[(entry.path, 0)] = IndexEntry.from_base(entry)
              
          if write:
              self.write()
          # END handle write
          
          return entries_added
  
      def _items_to_rela_paths(self, items):
          """Returns a list of repo-relative paths from the given items which
          may be absolute or relative paths, entries or blobs"""
          paths = list()
          for item in items:
              if isinstance(item, (BaseIndexEntry,(Blob, Submodule))):
                  paths.append(self._to_relative_path(item.path))
              elif isinstance(item, basestring):
                  paths.append(self._to_relative_path(item))
              else:
                  raise TypeError("Invalid item type: %r" % item)
          # END for each item
          return paths
  
      @post_clear_cache
      @default_index
      def remove(self, items, working_tree=False, **kwargs):
          """Remove the given items from the index and optionally from
          the working tree as well.
  
          :param items:
              Multiple types of items are supported which may be be freely mixed.
  
              - path string
                  Remove the given path at all stages. If it is a directory, you must
                  specify the r=True keyword argument to remove all file entries
                  below it. If absolute paths are given, they will be converted
                  to a path relative to the git repository directory containing
                  the working tree
  
                  The path string may include globs, such as *.c.
  
              - Blob Object
                  Only the path portion is used in this case.
  
              - BaseIndexEntry or compatible type
                  The only relevant information here Yis the path. The stage is ignored.
  
          :param working_tree:
              If True, the entry will also be removed from the working tree, physically
              removing the respective file. This may fail if there are uncommited changes
              in it.
  
          :param kwargs:
              Additional keyword arguments to be passed to git-rm, such
              as 'r' to allow recurive removal of
  
          :return:
              List(path_string, ...) list of repository relative paths that have
              been removed effectively.
              This is interesting to know in case you have provided a directory or
              globs. Paths are relative to the repository. """
          args = list()
          if not working_tree:
              args.append("--cached")
          args.append("--")
  
          # preprocess paths
          paths = self._items_to_rela_paths(items)
          removed_paths = self.repo.git.rm(args, paths, **kwargs).splitlines()
  
          # process output to gain proper paths
          # rm 'path'
          return [ p[4:-1] for p in removed_paths ]
  
      @post_clear_cache
      @default_index
      def move(self, items, skip_errors=False, **kwargs):
          """Rename/move the items, whereas the last item is considered the destination of
          the move operation. If the destination is a file, the first item ( of two )
          must be a file as well. If the destination is a directory, it may be preceeded
          by one or more directories or files.
  
          The working tree will be affected in non-bare repositories.
  
          :parma items:
              Multiple types of items are supported, please see the 'remove' method
              for reference.
          :param skip_errors:
              If True, errors such as ones resulting from missing source files will
              be skpped.
          :param kwargs:
              Additional arguments you would like to pass to git-mv, such as dry_run
              or force.
  
          :return:List(tuple(source_path_string, destination_path_string), ...)
              A list of pairs, containing the source file moved as well as its
              actual destination. Relative to the repository root.
  
          :raise ValueErorr: If only one item was given
              GitCommandError: If git could not handle your request"""
          args = list()
          if skip_errors:
              args.append('-k')
  
          paths = self._items_to_rela_paths(items)
          if len(paths) < 2:
              raise ValueError("Please provide at least one source and one destination of the move operation")
  
          was_dry_run = kwargs.pop('dry_run', kwargs.pop('n', None))
          kwargs['dry_run'] = True
  
          # first execute rename in dryrun so the command tells us what it actually does
          # ( for later output )
          out = list()
          mvlines = self.repo.git.mv(args, paths, **kwargs).splitlines()
  
          # parse result - first 0:n/2 lines are 'checking ', the remaining ones
          # are the 'renaming' ones which we parse
          for ln in xrange(len(mvlines)/2, len(mvlines)):
              tokens = mvlines[ln].split(' to ')
              assert len(tokens) == 2, "Too many tokens in %s" % mvlines[ln]
  
              # [0] = Renaming x
              # [1] = y
              out.append((tokens[0][9:], tokens[1]))
          # END for each line to parse
  
          # either prepare for the real run, or output the dry-run result
          if was_dry_run:
              return out
          # END handle dryrun
  
  
          # now apply the actual operation
          kwargs.pop('dry_run')
          self.repo.git.mv(args, paths, **kwargs)
  
          return out
  
      def commit(self, message, parent_commits=None, head=True):
          """Commit the current default index file, creating a commit object.
  
          For more information on the arguments, see tree.commit.
          :note:
              If you have manually altered the .entries member of this instance,
              don't forget to write() your changes to disk beforehand.
  
          :return:
              Commit object representing the new commit"""
          tree = self.write_tree()
          return Commit.create_from_tree(self.repo, tree, message, parent_commits, head)
  
      @classmethod
      def _flush_stdin_and_wait(cls, proc, ignore_stdout = False):
          proc.stdin.flush()
          proc.stdin.close()
          stdout = ''
          if not ignore_stdout:
              stdout = proc.stdout.read()
          proc.stdout.close()
          proc.wait()
          return stdout
  
      @default_index
      def checkout(self, paths=None, force=False, fprogress=lambda *args: None, **kwargs):
          """Checkout the given paths or all files from the version known to the index into
          the working tree.
          
          :note: Be sure you have written pending changes using the ``write`` method
              in case you have altered the enties dictionary directly
  
          :param paths:
              If None, all paths in the index will be checked out. Otherwise an iterable
              of relative or absolute paths or a single path pointing to files or directories
              in the index is expected.
  
          :param force:
              If True, existing files will be overwritten even if they contain local modifications.
              If False, these will trigger a CheckoutError.
  
          :param fprogress:
              see Index.add_ for signature and explanation.
              The provided progress information will contain None as path and item if no
              explicit paths are given. Otherwise progress information will be send
              prior and after a file has been checked out
  
          :param kwargs:
              Additional arguments to be pasesd to git-checkout-index
  
          :return:
              iterable yielding paths to files which have been checked out and are
              guaranteed to match the version stored in the index
  
          :raise CheckoutError:
              If at least one file failed to be checked out. This is a summary,
              hence it will checkout as many files as it can anyway.
              If one of files or directories do not exist in the index
              ( as opposed to the  original git command who ignores them ).
              Raise GitCommandError if error lines could not be parsed - this truly is
              an exceptional state
              
          .. note:: The checkout is limited to checking out the files in the 
              index. Files which are not in the index anymore and exist in 
              the working tree will not be deleted. This behaviour is fundamentally
              different to *head.checkout*, i.e. if you want git-checkout like behaviour, 
              use head.checkout instead of index.checkout.
              """
          args = ["--index"]
          if force:
              args.append("--force")
  
          def handle_stderr(proc, iter_checked_out_files):
              stderr = proc.stderr.read()
              if not stderr:
                  return
              # line contents:
              # git-checkout-index: this already exists
              failed_files = list()
              failed_reasons = list()
              unknown_lines = list()
              endings = (' already exists', ' is not in the cache', ' does not exist at stage', ' is unmerged')
              for line in stderr.splitlines():
                  if not line.startswith("git checkout-index: ") and not line.startswith("git-checkout-index: "):
                      is_a_dir = " is a directory"
                      unlink_issue = "unable to unlink old '"
                      already_exists_issue = ' already exists, no checkout'   # created by entry.c:checkout_entry(...)
                      if line.endswith(is_a_dir):
                          failed_files.append(line[:-len(is_a_dir)])
                          failed_reasons.append(is_a_dir)
                      elif line.startswith(unlink_issue):
                          failed_files.append(line[len(unlink_issue):line.rfind("'")])
                          failed_reasons.append(unlink_issue)
                      elif line.endswith(already_exists_issue):
                          failed_files.append(line[:-len(already_exists_issue)])
                          failed_reasons.append(already_exists_issue)
                      else:
                          unknown_lines.append(line)
                      continue
                  # END special lines parsing
  
                  for e in endings:
                      if line.endswith(e):
                          failed_files.append(line[20:-len(e)])
                          failed_reasons.append(e)
                          break
                      # END if ending matches
                  # END for each possible ending
              # END for each line
              if unknown_lines:
                  raise GitCommandError(("git-checkout-index", ), 128, stderr)
              if failed_files:
                  valid_files = list(set(iter_checked_out_files) - set(failed_files))
                  raise CheckoutError("Some files could not be checked out from the index due to local modifications", failed_files, valid_files, failed_reasons)
          # END stderr handler
  
  
          if paths is None:
              args.append("--all")
              kwargs['as_process'] = 1
              fprogress(None, False, None)
              proc = self.repo.git.checkout_index(*args, **kwargs)
              proc.wait()
              fprogress(None, True, None)
              rval_iter = ( e.path for e in self.entries.itervalues() )
              handle_stderr(proc, rval_iter)
              return rval_iter
          else:
              if isinstance(paths, basestring):
                  paths = [paths]
  
              # make sure we have our entries loaded before we start checkout_index
              # which will hold a lock on it. We try to get the lock as well during 
              # our entries initialization
              self.entries
              
              args.append("--stdin")
              kwargs['as_process'] = True
              kwargs['istream'] = subprocess.PIPE
              proc = self.repo.git.checkout_index(args, **kwargs)
              make_exc = lambda : GitCommandError(("git-checkout-index",)+tuple(args), 128, proc.stderr.read())
              checked_out_files = list()
  
              for path in paths:
                  co_path = to_native_path_linux(self._to_relative_path(path))
                  # if the item is not in the index, it could be a directory
                  path_is_directory = False
  
                  try:
                      self.entries[(co_path, 0)]
                  except KeyError:
                      dir = co_path
                      if not dir.endswith('/'):
                          dir += '/'
                      for entry in self.entries.itervalues():
                          if entry.path.startswith(dir):
                              p = entry.path
                              self._write_path_to_stdin(proc, p, p, make_exc, 
                                                          fprogress, read_from_stdout=False)
                              checked_out_files.append(p)
                              path_is_directory = True
                          # END if entry is in directory
                      # END for each entry
                  # END path exception handlnig
  
                  if not path_is_directory:
                      self._write_path_to_stdin(proc, co_path, path, make_exc, 
                                                  fprogress, read_from_stdout=False)
                      checked_out_files.append(co_path)
                  # END path is a file
              # END for each path
              self._flush_stdin_and_wait(proc, ignore_stdout=True)
  
              handle_stderr(proc, checked_out_files)
              return checked_out_files
          # END paths handling
          assert "Should not reach this point"
  
      @default_index
      def reset(self, commit='HEAD', working_tree=False, paths=None, head=False, **kwargs):
          """Reset the index to reflect the tree at the given commit. This will not
          adjust our HEAD reference as opposed to HEAD.reset by default.
  
          :param commit:
              Revision, Reference or Commit specifying the commit we should represent.
              If you want to specify a tree only, use IndexFile.from_tree and overwrite
              the default index.
  
          :param working_tree:
              If True, the files in the working tree will reflect the changed index.
              If False, the working tree will not be touched
              Please note that changes to the working copy will be discarded without
              warning !
              
          :param head:
              If True, the head will be set to the given commit. This is False by default,
              but if True, this method behaves like HEAD.reset.
              
          :param paths: if given as an iterable of absolute or repository-relative paths,
              only these will be reset to their state at the given commit'ish.
              The paths need to exist at the commit, otherwise an exception will be 
              raised.
  
          :param kwargs:
              Additional keyword arguments passed to git-reset
              
          .. note:: IndexFile.reset, as opposed to HEAD.reset, will not delete anyfiles
              in order to maintain a consistent working tree. Instead, it will just
              checkout the files according to their state in the index.
              If you want git-reset like behaviour, use *HEAD.reset* instead.
  
          :return: self """
          # what we actually want to do is to merge the tree into our existing
          # index, which is what git-read-tree does
          new_inst = type(self).from_tree(self.repo, commit)
          if not paths:
              self.entries = new_inst.entries
          else:
              nie = new_inst.entries
              for path in paths:
                  path = self._to_relative_path(path)
                  try:
                      key = entry_key(path, 0)
                      self.entries[key] = nie[key]
                  except KeyError:
                      # if key is not in theirs, it musn't be in ours
                      try:
                          del(self.entries[key])
                      except KeyError:
                          pass
                      # END handle deletion keyerror
                  # END handle keyerror
              # END for each path
          # END handle paths
          self.write()
          
          if working_tree:
              self.checkout(paths=paths, force=True)
          # END handle working tree
          
          if head:
              self.repo.head.set_commit(self.repo.commit(commit), logmsg="%s: Updating HEAD" % commit)
          # END handle head change
  
          return self
  
      @default_index
      def diff(self, other=diff.Diffable.Index, paths=None, create_patch=False, **kwargs):
          """Diff this index against the working copy or a Tree or Commit object
  
          For a documentation of the parameters and return values, see
          Diffable.diff
  
          :note:
              Will only work with indices that represent the default git index as
              they have not been initialized with a stream.
          """
          # index against index is always empty
          if other is self.Index:
              return diff.DiffIndex()
  
          # index against anything but None is a reverse diff with the respective
          # item. Handle existing -R flags properly. Transform strings to the object
          # so that we can call diff on it
          if isinstance(other, basestring):
              other = self.repo.rev_parse(other)
          # END object conversion
  
          if isinstance(other, Object):
              # invert the existing R flag
              cur_val = kwargs.get('R', False)
              kwargs['R'] = not cur_val
              return other.diff(self.Index, paths, create_patch, **kwargs)
          # END diff against other item handlin
  
          # if other is not None here, something is wrong
          if other is not None:
              raise ValueError( "other must be None, Diffable.Index, a Tree or Commit, was %r" % other )
  
          # diff against working copy - can be handled by superclass natively
          return super(IndexFile, self).diff(other, paths, create_patch, **kwargs)
  
  