Added EmptyChangeset into VCS module

rhodecode/lib/vcs/backends/base.py

@@ -1,911 +1,956
 # -*- coding: utf-8 -*-
 """
     vcs.backends.base
     ~~~~~~~~~~~~~~~~~
 
     Base for all available scm backends
 
     :created_on: Apr 8, 2010
     :copyright: (c) 2010-2011 by Marcin Kuzminski, Lukasz Balcerzak.
 """
 
 
 from itertools import chain
 from rhodecode.lib.vcs.utils import author_name, author_email
 from rhodecode.lib.vcs.utils.lazy import LazyProperty
 from rhodecode.lib.vcs.utils.helpers import get_dict_for_attrs
 from rhodecode.lib.vcs.conf import settings
 
 from rhodecode.lib.vcs.exceptions import ChangesetError, EmptyRepositoryError, \
     NodeAlreadyAddedError, NodeAlreadyChangedError, NodeAlreadyExistsError, \
     NodeAlreadyRemovedError, NodeDoesNotExistError, NodeNotChangedError, \
     RepositoryError
 
 
 class BaseRepository(object):
     """
     Base Repository for final backends
 
     **Attributes**
 
         ``DEFAULT_BRANCH_NAME``
             name of default branch (i.e. "trunk" for svn, "master" for git etc.
 
         ``scm``
             alias of scm, i.e. *git* or *hg*
 
         ``repo``
             object from external api
 
         ``revisions``
             list of all available revisions' ids, in ascending order
 
         ``changesets``
             storage dict caching returned changesets
 
         ``path``
             absolute path to the repository
 
         ``branches``
             branches as list of changesets
 
         ``tags``
             tags as list of changesets
     """
     scm = None
     DEFAULT_BRANCH_NAME = None
     EMPTY_CHANGESET = '0' * 40
 
     def __init__(self, repo_path, create=False, **kwargs):
         """
         Initializes repository. Raises RepositoryError if repository could
         not be find at the given ``repo_path`` or directory at ``repo_path``
         exists and ``create`` is set to True.
 
         :param repo_path: local path of the repository
         :param create=False: if set to True, would try to craete repository.
         :param src_url=None: if set, should be proper url from which repository
           would be cloned; requires ``create`` parameter to be set to True -
           raises RepositoryError if src_url is set and create evaluates to
           False
         """
         raise NotImplementedError
 
     def __str__(self):
         return '<%s at %s>' % (self.__class__.__name__, self.path)
 
     def __repr__(self):
         return self.__str__()
 
     def __len__(self):
         return self.count()
 
     @LazyProperty
     def alias(self):
         for k, v in settings.BACKENDS.items():
             if v.split('.')[-1] == str(self.__class__.__name__):
                 return k
 
     @LazyProperty
     def name(self):
         raise NotImplementedError
 
     @LazyProperty
     def owner(self):
         raise NotImplementedError
 
     @LazyProperty
     def description(self):
         raise NotImplementedError
 
     @LazyProperty
     def size(self):
         """
         Returns combined size in bytes for all repository files
         """
 
         size = 0
         try:
             tip = self.get_changeset()
             for topnode, dirs, files in tip.walk('/'):
                 for f in files:
                     size += tip.get_file_size(f.path)
                 for dir in dirs:
                     for f in files:
                         size += tip.get_file_size(f.path)
 
         except RepositoryError, e:
             pass
         return size
 
     def is_valid(self):
         """
         Validates repository.
         """
         raise NotImplementedError
 
     def get_last_change(self):
         self.get_changesets()
 
     #==========================================================================
     # CHANGESETS
     #==========================================================================
 
     def get_changeset(self, revision=None):
         """
         Returns instance of ``Changeset`` class. If ``revision`` is None, most
         recent changeset is returned.
 
         :raises ``EmptyRepositoryError``: if there are no revisions
         """
         raise NotImplementedError
 
     def __iter__(self):
         """
         Allows Repository objects to be iterated.
 
         *Requires* implementation of ``__getitem__`` method.
         """
         for revision in self.revisions:
             yield self.get_changeset(revision)
 
     def get_changesets(self, start=None, end=None, start_date=None,
                        end_date=None, branch_name=None, reverse=False):
         """
         Returns iterator of ``MercurialChangeset`` objects from start to end
         not inclusive This should behave just like a list, ie. end is not
         inclusive
 
         :param start: None or str
         :param end: None or str
         :param start_date:
         :param end_date:
         :param branch_name:
         :param reversed:
         """
         raise NotImplementedError
 
     def __getslice__(self, i, j):
         """
         Returns a iterator of sliced repository
         """
         for rev in self.revisions[i:j]:
             yield self.get_changeset(rev)
 
     def __getitem__(self, key):
         return self.get_changeset(key)
 
     def count(self):
         return len(self.revisions)
 
     def tag(self, name, user, revision=None, message=None, date=None, **opts):
         """
         Creates and returns a tag for the given ``revision``.
 
         :param name: name for new tag
         :param user: full username, i.e.: "Joe Doe <[e-mail]>"
         :param revision: changeset id for which new tag would be created
         :param message: message of the tag's commit
         :param date: date of tag's commit
 
         :raises TagAlreadyExistError: if tag with same name already exists
         """
         raise NotImplementedError
 
     def remove_tag(self, name, user, message=None, date=None):
         """
         Removes tag with the given ``name``.
 
         :param name: name of the tag to be removed
         :param user: full username, i.e.: "Joe Doe <[e-mail]>"
         :param message: message of the tag's removal commit
         :param date: date of tag's removal commit
 
         :raises TagDoesNotExistError: if tag with given name does not exists
         """
         raise NotImplementedError
 
     def get_diff(self, rev1, rev2, path=None, ignore_whitespace=False,
             context=3):
         """
         Returns (git like) *diff*, as plain text. Shows changes introduced by
         ``rev2`` since ``rev1``.
 
         :param rev1: Entry point from which diff is shown. Can be
           ``self.EMPTY_CHANGESET`` - in this case, patch showing all
           the changes since empty state of the repository until ``rev2``
         :param rev2: Until which revision changes should be shown.
         :param ignore_whitespace: If set to ``True``, would not show whitespace
           changes. Defaults to ``False``.
         :param context: How many lines before/after changed lines should be
           shown. Defaults to ``3``.
         """
         raise NotImplementedError
 
     # ========== #
     # COMMIT API #
     # ========== #
 
     @LazyProperty
     def in_memory_changeset(self):
         """
         Returns ``InMemoryChangeset`` object for this repository.
         """
         raise NotImplementedError
 
     def add(self, filenode, **kwargs):
         """
         Commit api function that will add given ``FileNode`` into this
         repository.
 
         :raises ``NodeAlreadyExistsError``: if there is a file with same path
           already in repository
         :raises ``NodeAlreadyAddedError``: if given node is already marked as
           *added*
         """
         raise NotImplementedError
 
     def remove(self, filenode, **kwargs):
         """
         Commit api function that will remove given ``FileNode`` into this
         repository.
 
         :raises ``EmptyRepositoryError``: if there are no changesets yet
         :raises ``NodeDoesNotExistError``: if there is no file with given path
         """
         raise NotImplementedError
 
     def commit(self, message, **kwargs):
         """
         Persists current changes made on this repository and returns newly
         created changeset.
 
         :raises ``NothingChangedError``: if no changes has been made
         """
         raise NotImplementedError
 
     def get_state(self):
         """
         Returns dictionary with ``added``, ``changed`` and ``removed`` lists
         containing ``FileNode`` objects.
         """
         raise NotImplementedError
 
     def get_config_value(self, section, name, config_file=None):
         """
         Returns configuration value for a given [``section``] and ``name``.
 
         :param section: Section we want to retrieve value from
         :param name: Name of configuration we want to retrieve
         :param config_file: A path to file which should be used to retrieve
           configuration from (might also be a list of file paths)
         """
         raise NotImplementedError
 
     def get_user_name(self, config_file=None):
         """
         Returns user's name from global configuration file.
 
         :param config_file: A path to file which should be used to retrieve
           configuration from (might also be a list of file paths)
         """
         raise NotImplementedError
 
     def get_user_email(self, config_file=None):
         """
         Returns user's email from global configuration file.
 
         :param config_file: A path to file which should be used to retrieve
           configuration from (might also be a list of file paths)
         """
         raise NotImplementedError
 
     # =========== #
     # WORKDIR API #
     # =========== #
 
     @LazyProperty
     def workdir(self):
         """
         Returns ``Workdir`` instance for this repository.
         """
         raise NotImplementedError
 
 
 class BaseChangeset(object):
     """
     Each backend should implement it's changeset representation.
 
     **Attributes**
 
         ``repository``
             repository object within which changeset exists
 
         ``id``
             may be ``raw_id`` or i.e. for mercurial's tip just ``tip``
 
         ``raw_id``
             raw changeset representation (i.e. full 40 length sha for git
             backend)
 
         ``short_id``
             shortened (if apply) version of ``raw_id``; it would be simple
             shortcut for ``raw_id[:12]`` for git/mercurial backends or same
             as ``raw_id`` for subversion
 
         ``revision``
             revision number as integer
 
         ``files``
             list of ``FileNode`` (``Node`` with NodeKind.FILE) objects
 
         ``dirs``
             list of ``DirNode`` (``Node`` with NodeKind.DIR) objects
 
         ``nodes``
             combined list of ``Node`` objects
 
         ``author``
             author of the changeset, as unicode
 
         ``message``
             message of the changeset, as unicode
 
         ``parents``
             list of parent changesets
 
         ``last``
             ``True`` if this is last changeset in repository, ``False``
             otherwise; trying to access this attribute while there is no
             changesets would raise ``EmptyRepositoryError``
     """
     def __str__(self):
         return '<%s at %s:%s>' % (self.__class__.__name__, self.revision,
             self.short_id)
 
     def __repr__(self):
         return self.__str__()
 
     def __unicode__(self):
         return u'%s:%s' % (self.revision, self.short_id)
 
     def __eq__(self, other):
         return self.raw_id == other.raw_id
 
     @LazyProperty
     def last(self):
         if self.repository is None:
             raise ChangesetError("Cannot check if it's most recent revision")
         return self.raw_id == self.repository.revisions[-1]
 
     @LazyProperty
     def parents(self):
         """
         Returns list of parents changesets.
         """
         raise NotImplementedError
 
     @LazyProperty
     def id(self):
         """
         Returns string identifying this changeset.
         """
         raise NotImplementedError
 
     @LazyProperty
     def raw_id(self):
         """
         Returns raw string identifying this changeset.
         """
         raise NotImplementedError
 
     @LazyProperty
     def short_id(self):
         """
         Returns shortened version of ``raw_id`` attribute, as string,
         identifying this changeset, useful for web representation.
         """
         raise NotImplementedError
 
     @LazyProperty
     def revision(self):
         """
         Returns integer identifying this changeset.
 
         """
         raise NotImplementedError
 
     @LazyProperty
     def author(self):
         """
         Returns Author for given commit
         """
 
         raise NotImplementedError
 
     @LazyProperty
     def author_name(self):
         """
         Returns Author name for given commit
         """
 
         return author_name(self.author)
 
     @LazyProperty
     def author_email(self):
         """
         Returns Author email address for given commit
         """
 
         return author_email(self.author)
 
     def get_file_mode(self, path):
         """
         Returns stat mode of the file at the given ``path``.
         """
         raise NotImplementedError
 
     def get_file_content(self, path):
         """
         Returns content of the file at the given ``path``.
         """
         raise NotImplementedError
 
     def get_file_size(self, path):
         """
         Returns size of the file at the given ``path``.
         """
         raise NotImplementedError
 
     def get_file_changeset(self, path):
         """
         Returns last commit of the file at the given ``path``.
         """
         raise NotImplementedError
 
     def get_file_history(self, path):
         """
         Returns history of file as reversed list of ``Changeset`` objects for
         which file at given ``path`` has been modified.
         """
         raise NotImplementedError
 
     def get_nodes(self, path):
         """
         Returns combined ``DirNode`` and ``FileNode`` objects list representing
         state of changeset at the given ``path``.
 
         :raises ``ChangesetError``: if node at the given ``path`` is not
           instance of ``DirNode``
         """
         raise NotImplementedError
 
     def get_node(self, path):
         """
         Returns ``Node`` object from the given ``path``.
 
         :raises ``NodeDoesNotExistError``: if there is no node at the given
           ``path``
         """
         raise NotImplementedError
 
     def fill_archive(self, stream=None, kind='tgz', prefix=None):
         """
         Fills up given stream.
 
         :param stream: file like object.
         :param kind: one of following: ``zip``, ``tar``, ``tgz``
             or ``tbz2``. Default: ``tgz``.
         :param prefix: name of root directory in archive.
             Default is repository name and changeset's raw_id joined with dash.
 
             repo-tip.<kind>
         """
 
         raise NotImplementedError
 
     def get_chunked_archive(self, **kwargs):
         """
         Returns iterable archive. Tiny wrapper around ``fill_archive`` method.
 
         :param chunk_size: extra parameter which controls size of returned
             chunks. Default:8k.
         """
 
         chunk_size = kwargs.pop('chunk_size', 8192)
         stream = kwargs.get('stream')
         self.fill_archive(**kwargs)
         while True:
             data = stream.read(chunk_size)
             if not data:
                 break
             yield data
 
     @LazyProperty
     def root(self):
         """
         Returns ``RootNode`` object for this changeset.
         """
         return self.get_node('')
 
     def next(self, branch=None):
         """
         Returns next changeset from current, if branch is gives it will return
         next changeset belonging to this branch
 
         :param branch: show changesets within the given named branch
         """
         raise NotImplementedError
 
     def prev(self, branch=None):
         """
         Returns previous changeset from current, if branch is gives it will
         return previous changeset belonging to this branch
 
         :param branch: show changesets within the given named branch
         """
         raise NotImplementedError
 
     @LazyProperty
     def added(self):
         """
         Returns list of added ``FileNode`` objects.
         """
         raise NotImplementedError
 
     @LazyProperty
     def changed(self):
         """
         Returns list of modified ``FileNode`` objects.
         """
         raise NotImplementedError
 
     @LazyProperty
     def removed(self):
         """
         Returns list of removed ``FileNode`` objects.
         """
         raise NotImplementedError
 
     @LazyProperty
     def size(self):
         """
         Returns total number of bytes from contents of all filenodes.
         """
         return sum((node.size for node in self.get_filenodes_generator()))
 
     def walk(self, topurl=''):
         """
         Similar to os.walk method. Insted of filesystem it walks through
         changeset starting at given ``topurl``.  Returns generator of tuples
         (topnode, dirnodes, filenodes).
         """
         topnode = self.get_node(topurl)
         yield (topnode, topnode.dirs, topnode.files)
         for dirnode in topnode.dirs:
             for tup in self.walk(dirnode.path):
                 yield tup
 
     def get_filenodes_generator(self):
         """
         Returns generator that yields *all* file nodes.
         """
         for topnode, dirs, files in self.walk():
             for node in files:
                 yield node
 
     def as_dict(self):
         """
         Returns dictionary with changeset's attributes and their values.
         """
         data = get_dict_for_attrs(self, ['id', 'raw_id', 'short_id',
             'revision', 'date', 'message'])
         data['author'] = {'name': self.author_name, 'email': self.author_email}
         data['added'] = [node.path for node in self.added]
         data['changed'] = [node.path for node in self.changed]
         data['removed'] = [node.path for node in self.removed]
         return data
 
 
 class BaseWorkdir(object):
     """
     Working directory representation of single repository.
 
     :attribute: repository: repository object of working directory
     """
 
     def __init__(self, repository):
         self.repository = repository
 
     def get_branch(self):
         """
         Returns name of current branch.
         """
         raise NotImplementedError
 
     def get_changeset(self):
         """
         Returns current changeset.
         """
         raise NotImplementedError
 
     def get_added(self):
         """
         Returns list of ``FileNode`` objects marked as *new* in working
         directory.
         """
         raise NotImplementedError
 
     def get_changed(self):
         """
         Returns list of ``FileNode`` objects *changed* in working directory.
         """
         raise NotImplementedError
 
     def get_removed(self):
         """
         Returns list of ``RemovedFileNode`` objects marked as *removed* in
         working directory.
         """
         raise NotImplementedError
 
     def get_untracked(self):
         """
         Returns list of ``FileNode`` objects which are present within working
         directory however are not tracked by repository.
         """
         raise NotImplementedError
 
     def get_status(self):
         """
         Returns dict with ``added``, ``changed``, ``removed`` and ``untracked``
         lists.
         """
         raise NotImplementedError
 
     def commit(self, message, **kwargs):
         """
         Commits local (from working directory) changes and returns newly
         created
         ``Changeset``. Updates repository's ``revisions`` list.
 
         :raises ``CommitError``: if any error occurs while committing
         """
         raise NotImplementedError
 
     def update(self, revision=None):
         """
         Fetches content of the given revision and populates it within working
         directory.
         """
         raise NotImplementedError
 
     def checkout_branch(self, branch=None):
         """
         Checks out ``branch`` or the backend's default branch.
 
         Raises ``BranchDoesNotExistError`` if the branch does not exist.
         """
         raise NotImplementedError
 
 
 class BaseInMemoryChangeset(object):
     """
     Represents differences between repository's state (most recent head) and
     changes made *in place*.
 
     **Attributes**
 
         ``repository``
             repository object for this in-memory-changeset
 
         ``added``
             list of ``FileNode`` objects marked as *added*
 
         ``changed``
             list of ``FileNode`` objects marked as *changed*
 
         ``removed``
             list of ``FileNode`` or ``RemovedFileNode`` objects marked to be
             *removed*
 
         ``parents``
             list of ``Changeset`` representing parents of in-memory changeset.
             Should always be 2-element sequence.
 
     """
 
     def __init__(self, repository):
         self.repository = repository
         self.added = []
         self.changed = []
         self.removed = []
         self.parents = []
 
     def add(self, *filenodes):
         """
         Marks given ``FileNode`` objects as *to be committed*.
 
         :raises ``NodeAlreadyExistsError``: if node with same path exists at
           latest changeset
         :raises ``NodeAlreadyAddedError``: if node with same path is already
           marked as *added*
         """
         # Check if not already marked as *added* first
         for node in filenodes:
             if node.path in (n.path for n in self.added):
                 raise NodeAlreadyAddedError("Such FileNode %s is already "
                     "marked for addition" % node.path)
         for node in filenodes:
             self.added.append(node)
 
     def change(self, *filenodes):
         """
         Marks given ``FileNode`` objects to be *changed* in next commit.
 
         :raises ``EmptyRepositoryError``: if there are no changesets yet
         :raises ``NodeAlreadyExistsError``: if node with same path is already
           marked to be *changed*
         :raises ``NodeAlreadyRemovedError``: if node with same path is already
           marked to be *removed*
         :raises ``NodeDoesNotExistError``: if node doesn't exist in latest
           changeset
         :raises ``NodeNotChangedError``: if node hasn't really be changed
         """
         for node in filenodes:
             if node.path in (n.path for n in self.removed):
                 raise NodeAlreadyRemovedError("Node at %s is already marked "
                     "as removed" % node.path)
         try:
             self.repository.get_changeset()
         except EmptyRepositoryError:
             raise EmptyRepositoryError("Nothing to change - try to *add* new "
                 "nodes rather than changing them")
         for node in filenodes:
             if node.path in (n.path for n in self.changed):
                 raise NodeAlreadyChangedError("Node at '%s' is already "
                     "marked as changed" % node.path)
             self.changed.append(node)
 
     def remove(self, *filenodes):
         """
         Marks given ``FileNode`` (or ``RemovedFileNode``) objects to be
         *removed* in next commit.
 
         :raises ``NodeAlreadyRemovedError``: if node has been already marked to
           be *removed*
         :raises ``NodeAlreadyChangedError``: if node has been already marked to
           be *changed*
         """
         for node in filenodes:
             if node.path in (n.path for n in self.removed):
                 raise NodeAlreadyRemovedError("Node is already marked to "
                     "for removal at %s" % node.path)
             if node.path in (n.path for n in self.changed):
                 raise NodeAlreadyChangedError("Node is already marked to "
                     "be changed at %s" % node.path)
             # We only mark node as *removed* - real removal is done by
             # commit method
             self.removed.append(node)
 
     def reset(self):
         """
         Resets this instance to initial state (cleans ``added``, ``changed``
         and ``removed`` lists).
         """
         self.added = []
         self.changed = []
         self.removed = []
         self.parents = []
 
     def get_ipaths(self):
         """
         Returns generator of paths from nodes marked as added, changed or
         removed.
         """
         for node in chain(self.added, self.changed, self.removed):
             yield node.path
 
     def get_paths(self):
         """
         Returns list of paths from nodes marked as added, changed or removed.
         """
         return list(self.get_ipaths())
 
     def check_integrity(self, parents=None):
         """
         Checks in-memory changeset's integrity. Also, sets parents if not
         already set.
 
         :raises CommitError: if any error occurs (i.e.
           ``NodeDoesNotExistError``).
         """
         if not self.parents:
             parents = parents or []
             if len(parents) == 0:
                 try:
                     parents = [self.repository.get_changeset(), None]
                 except EmptyRepositoryError:
                     parents = [None, None]
             elif len(parents) == 1:
                 parents += [None]
             self.parents = parents
 
         # Local parents, only if not None
         parents = [p for p in self.parents if p]
 
         # Check nodes marked as added
         for p in parents:
             for node in self.added:
                 try:
                     p.get_node(node.path)
                 except NodeDoesNotExistError:
                     pass
                 else:
                     raise NodeAlreadyExistsError("Node at %s already exists "
                         "at %s" % (node.path, p))
 
         # Check nodes marked as changed
         missing = set(self.changed)
         not_changed = set(self.changed)
         if self.changed and not parents:
             raise NodeDoesNotExistError(str(self.changed[0].path))
         for p in parents:
             for node in self.changed:
                 try:
                     old = p.get_node(node.path)
                     missing.remove(node)
                     if old.content != node.content:
                         not_changed.remove(node)
                 except NodeDoesNotExistError:
                     pass
         if self.changed and missing:
             raise NodeDoesNotExistError("Node at %s is missing "
                 "(parents: %s)" % (node.path, parents))
 
         if self.changed and not_changed:
             raise NodeNotChangedError("Node at %s wasn't actually changed "
                 "since parents' changesets: %s" % (not_changed.pop().path,
                     parents)
             )
 
         # Check nodes marked as removed
         if self.removed and not parents:
             raise NodeDoesNotExistError("Cannot remove node at %s as there "
                 "were no parents specified" % self.removed[0].path)
         really_removed = set()
         for p in parents:
             for node in self.removed:
                 try:
                     p.get_node(node.path)
                     really_removed.add(node)
                 except ChangesetError:
                     pass
         not_removed = set(self.removed) - really_removed
         if not_removed:
             raise NodeDoesNotExistError("Cannot remove node at %s from "
                 "following parents: %s" % (not_removed[0], parents))
 
     def commit(self, message, author, parents=None, branch=None, date=None,
             **kwargs):
         """
         Performs in-memory commit (doesn't check workdir in any way) and
         returns newly created ``Changeset``. Updates repository's
         ``revisions``.
 
         .. note::
             While overriding this method each backend's should call
             ``self.check_integrity(parents)`` in the first place.
 
         :param message: message of the commit
         :param author: full username, i.e. "Joe Doe <[e-mail]>"
         :param parents: single parent or sequence of parents from which commit
           would be derieved
         :param date: ``datetime.datetime`` instance. Defaults to
           ``datetime.datetime.now()``.
         :param branch: branch name, as string. If none given, default backend's
           branch would be used.
 
         :raises ``CommitError``: if any error occurs while committing
         """
         raise NotImplementedError
+
+
+class EmptyChangeset(BaseChangeset):
+    """
+    An dummy empty changeset. It's possible to pass hash when creating
+    an EmptyChangeset
+    """
+
+    def __init__(self, cs='0' * 40, repo=None, requested_revision=None,
+                 alias=None):
+        self._empty_cs = cs
+        self.revision = -1
+        self.message = ''
+        self.author = ''
+        self.date = ''
+        self.repository = repo
+        self.requested_revision = requested_revision
+        self.alias = alias
+
+    @LazyProperty
+    def raw_id(self):
+        """
+        Returns raw string identifying this changeset, useful for web
+        representation.
+        """
+
+        return self._empty_cs
+
+    @LazyProperty
+    def branch(self):
+        from rhodecode.lib.vcs.backends import get_backend
+        return get_backend(self.alias).DEFAULT_BRANCH_NAME
+
+    @LazyProperty
+    def short_id(self):
+        return self.raw_id[:12]
+
+    def get_file_changeset(self, path):
+        return self
+
+    def get_file_content(self, path):
+        return u''
+
+    def get_file_size(self, path):
+        return 0
  No newline at end of file

rhodecode/lib/vcs/nodes.py

@@ -1,611 +1,611
 # -*- coding: utf-8 -*-
 """
     vcs.nodes
     ~~~~~~~~~
 
     Module holding everything related to vcs nodes.
 
     :created_on: Apr 8, 2010
     :copyright: (c) 2010-2011 by Marcin Kuzminski, Lukasz Balcerzak.
 """
 import os
 import stat
 import posixpath
 import mimetypes
 
 from pygments import lexers
 
 from rhodecode.lib.vcs.utils.lazy import LazyProperty
 from rhodecode.lib.vcs.utils import safe_unicode, safe_str
 from rhodecode.lib.vcs.exceptions import NodeError
 from rhodecode.lib.vcs.exceptions import RemovedFileNodeError
-from rhodecode.lib.utils import EmptyChangeset
+from rhodecode.lib.vcs.backends.base import EmptyChangeset
 
 
 class NodeKind:
     SUBMODULE = -1
     DIR = 1
     FILE = 2
 
 
 class NodeState:
     ADDED = u'added'
     CHANGED = u'changed'
     NOT_CHANGED = u'not changed'
     REMOVED = u'removed'
 
 
 class NodeGeneratorBase(object):
     """
     Base class for removed added and changed filenodes, it's a lazy generator
     class that will create filenodes only on iteration or call
 
     The len method doesn't need to create filenodes at all
     """
 
     def __init__(self, current_paths, cs):
         self.cs = cs
         self.current_paths = current_paths
 
     def __call__(self):
         return [n for n in self]
 
     def __getslice__(self, i, j):
         for p in self.current_paths[i:j]:
             yield self.cs.get_node(p)
 
     def __len__(self):
         return len(self.current_paths)
 
     def __iter__(self):
         for p in self.current_paths:
             yield self.cs.get_node(p)
 
 
 class AddedFileNodesGenerator(NodeGeneratorBase):
     """
     Class holding Added files for current changeset
     """
     pass
 
 
 class ChangedFileNodesGenerator(NodeGeneratorBase):
     """
     Class holding Changed files for current changeset
     """
     pass
 
 
 class RemovedFileNodesGenerator(NodeGeneratorBase):
     """
     Class holding removed files for current changeset
     """
     def __iter__(self):
         for p in self.current_paths:
             yield RemovedFileNode(path=p)
 
     def __getslice__(self, i, j):
         for p in self.current_paths[i:j]:
             yield RemovedFileNode(path=p)
 
 
 class Node(object):
     """
     Simplest class representing file or directory on repository.  SCM backends
     should use ``FileNode`` and ``DirNode`` subclasses rather than ``Node``
     directly.
 
     Node's ``path`` cannot start with slash as we operate on *relative* paths
     only. Moreover, every single node is identified by the ``path`` attribute,
     so it cannot end with slash, too. Otherwise, path could lead to mistakes.
     """
 
     def __init__(self, path, kind):
         if path.startswith('/'):
             raise NodeError("Cannot initialize Node objects with slash at "
                 "the beginning as only relative paths are supported")
         self.path = path.rstrip('/')
         if path == '' and kind != NodeKind.DIR:
             raise NodeError("Only DirNode and its subclasses may be "
                             "initialized with empty path")
         self.kind = kind
         #self.dirs, self.files = [], []
         if self.is_root() and not self.is_dir():
             raise NodeError("Root node cannot be FILE kind")
 
     @LazyProperty
     def parent(self):
         parent_path = self.get_parent_path()
         if parent_path:
             if self.changeset:
                 return self.changeset.get_node(parent_path)
             return DirNode(parent_path)
         return None
 
     @LazyProperty
     def unicode_path(self):
         return safe_unicode(self.path)
 
     @LazyProperty
     def name(self):
         """
         Returns name of the node so if its path
         then only last part is returned.
         """
         return safe_unicode(self.path.rstrip('/').split('/')[-1])
 
     def _get_kind(self):
         return self._kind
 
     def _set_kind(self, kind):
         if hasattr(self, '_kind'):
             raise NodeError("Cannot change node's kind")
         else:
             self._kind = kind
             # Post setter check (path's trailing slash)
             if self.path.endswith('/'):
                 raise NodeError("Node's path cannot end with slash")
 
     kind = property(_get_kind, _set_kind)
 
     def __cmp__(self, other):
         """
         Comparator using name of the node, needed for quick list sorting.
         """
         kind_cmp = cmp(self.kind, other.kind)
         if kind_cmp:
             return kind_cmp
         return cmp(self.name, other.name)
 
     def __eq__(self, other):
         for attr in ['name', 'path', 'kind']:
             if getattr(self, attr) != getattr(other, attr):
                 return False
         if self.is_file():
             if self.content != other.content:
                 return False
         else:
             # For DirNode's check without entering each dir
             self_nodes_paths = list(sorted(n.path for n in self.nodes))
             other_nodes_paths = list(sorted(n.path for n in self.nodes))
             if self_nodes_paths != other_nodes_paths:
                 return False
         return True
 
     def __nq__(self, other):
         return not self.__eq__(other)
 
     def __repr__(self):
         return '<%s %r>' % (self.__class__.__name__, self.path)
 
     def __str__(self):
         return self.__repr__()
 
     def __unicode__(self):
         return self.name
 
     def get_parent_path(self):
         """
         Returns node's parent path or empty string if node is root.
         """
         if self.is_root():
             return ''
         return posixpath.dirname(self.path.rstrip('/')) + '/'
 
     def is_file(self):
         """
         Returns ``True`` if node's kind is ``NodeKind.FILE``, ``False``
         otherwise.
         """
         return self.kind == NodeKind.FILE
 
     def is_dir(self):
         """
         Returns ``True`` if node's kind is ``NodeKind.DIR``, ``False``
         otherwise.
         """
         return self.kind == NodeKind.DIR
 
     def is_root(self):
         """
         Returns ``True`` if node is a root node and ``False`` otherwise.
         """
         return self.kind == NodeKind.DIR and self.path == ''
 
     def is_submodule(self):
         """
         Returns ``True`` if node's kind is ``NodeKind.SUBMODULE``, ``False``
         otherwise.
         """
         return self.kind == NodeKind.SUBMODULE
 
     @LazyProperty
     def added(self):
         return self.state is NodeState.ADDED
 
     @LazyProperty
     def changed(self):
         return self.state is NodeState.CHANGED
 
     @LazyProperty
     def not_changed(self):
         return self.state is NodeState.NOT_CHANGED
 
     @LazyProperty
     def removed(self):
         return self.state is NodeState.REMOVED
 
 
 class FileNode(Node):
     """
     Class representing file nodes.
 
     :attribute: path: path to the node, relative to repostiory's root
     :attribute: content: if given arbitrary sets content of the file
     :attribute: changeset: if given, first time content is accessed, callback
     :attribute: mode: octal stat mode for a node. Default is 0100644.
     """
 
     def __init__(self, path, content=None, changeset=None, mode=None):
         """
         Only one of ``content`` and ``changeset`` may be given. Passing both
         would raise ``NodeError`` exception.
 
         :param path: relative path to the node
         :param content: content may be passed to constructor
         :param changeset: if given, will use it to lazily fetch content
         :param mode: octal representation of ST_MODE (i.e. 0100644)
         """
 
         if content and changeset:
             raise NodeError("Cannot use both content and changeset")
         super(FileNode, self).__init__(path, kind=NodeKind.FILE)
         self.changeset = changeset
         self._content = content
         self._mode = mode or 0100644
 
     @LazyProperty
     def mode(self):
         """
         Returns lazily mode of the FileNode. If ``changeset`` is not set, would
         use value given at initialization or 0100644 (default).
         """
         if self.changeset:
             mode = self.changeset.get_file_mode(self.path)
         else:
             mode = self._mode
         return mode
 
     @property
     def content(self):
         """
         Returns lazily content of the FileNode. If possible, would try to
         decode content from UTF-8.
         """
         if self.changeset:
             content = self.changeset.get_file_content(self.path)
         else:
             content = self._content
 
         if bool(content and '\0' in content):
             return content
         return safe_unicode(content)
 
     @LazyProperty
     def size(self):
         if self.changeset:
             return self.changeset.get_file_size(self.path)
         raise NodeError("Cannot retrieve size of the file without related "
             "changeset attribute")
 
     @LazyProperty
     def message(self):
         if self.changeset:
             return self.last_changeset.message
         raise NodeError("Cannot retrieve message of the file without related "
             "changeset attribute")
 
     @LazyProperty
     def last_changeset(self):
         if self.changeset:
             return self.changeset.get_file_changeset(self.path)
         raise NodeError("Cannot retrieve last changeset of the file without "
             "related changeset attribute")
 
     def get_mimetype(self):
         """
         Mimetype is calculated based on the file's content. If ``_mimetype``
         attribute is available, it will be returned (backends which store
         mimetypes or can easily recognize them, should set this private
         attribute to indicate that type should *NOT* be calculated).
         """
         if hasattr(self, '_mimetype'):
             if (isinstance(self._mimetype, (tuple, list,)) and
                 len(self._mimetype) == 2):
                 return self._mimetype
             else:
                 raise NodeError('given _mimetype attribute must be an 2 '
                                'element list or tuple')
 
         mtype, encoding = mimetypes.guess_type(self.name)
 
         if mtype is None:
             if self.is_binary:
                 mtype = 'application/octet-stream'
                 encoding = None
             else:
                 mtype = 'text/plain'
                 encoding = None
         return mtype, encoding
 
     @LazyProperty
     def mimetype(self):
         """
         Wrapper around full mimetype info. It returns only type of fetched
         mimetype without the encoding part. use get_mimetype function to fetch
         full set of (type,encoding)
         """
         return self.get_mimetype()[0]
 
     @LazyProperty
     def mimetype_main(self):
         return self.mimetype.split('/')[0]
 
     @LazyProperty
     def lexer(self):
         """
         Returns pygment's lexer class. Would try to guess lexer taking file's
         content, name and mimetype.
         """
         try:
             lexer = lexers.guess_lexer_for_filename(self.name, self.content)
         except lexers.ClassNotFound:
             lexer = lexers.TextLexer()
         # returns first alias
         return lexer
 
     @LazyProperty
     def lexer_alias(self):
         """
         Returns first alias of the lexer guessed for this file.
         """
         return self.lexer.aliases[0]
 
     @LazyProperty
     def history(self):
         """
         Returns a list of changeset for this file in which the file was changed
         """
         if self.changeset is None:
             raise NodeError('Unable to get changeset for this FileNode')
         return self.changeset.get_file_history(self.path)
 
     @LazyProperty
     def annotate(self):
         """
         Returns a list of three element tuples with lineno,changeset and line
         """
         if self.changeset is None:
             raise NodeError('Unable to get changeset for this FileNode')
         return self.changeset.get_file_annotate(self.path)
 
     @LazyProperty
     def state(self):
         if not self.changeset:
             raise NodeError("Cannot check state of the node if it's not "
                 "linked with changeset")
         elif self.path in (node.path for node in self.changeset.added):
             return NodeState.ADDED
         elif self.path in (node.path for node in self.changeset.changed):
             return NodeState.CHANGED
         else:
             return NodeState.NOT_CHANGED
 
     @property
     def is_binary(self):
         """
         Returns True if file has binary content.
         """
         _bin = '\0' in self.content
         return _bin
 
     @LazyProperty
     def extension(self):
         """Returns filenode extension"""
         return self.name.split('.')[-1]
 
     def is_executable(self):
         """
         Returns ``True`` if file has executable flag turned on.
         """
         return bool(self.mode & stat.S_IXUSR)
 
     def __repr__(self):
         return '<%s %r @ %s>' % (self.__class__.__name__, self.path,
                                  self.changeset.short_id)
 
 
 class RemovedFileNode(FileNode):
     """
     Dummy FileNode class - trying to access any public attribute except path,
     name, kind or state (or methods/attributes checking those two) would raise
     RemovedFileNodeError.
     """
     ALLOWED_ATTRIBUTES = ['name', 'path', 'state', 'is_root', 'is_file',
         'is_dir', 'kind', 'added', 'changed', 'not_changed', 'removed']
 
     def __init__(self, path):
         """
         :param path: relative path to the node
         """
         super(RemovedFileNode, self).__init__(path=path)
 
     def __getattribute__(self, attr):
         if attr.startswith('_') or attr in RemovedFileNode.ALLOWED_ATTRIBUTES:
             return super(RemovedFileNode, self).__getattribute__(attr)
         raise RemovedFileNodeError("Cannot access attribute %s on "
             "RemovedFileNode" % attr)
 
     @LazyProperty
     def state(self):
         return NodeState.REMOVED
 
 
 class DirNode(Node):
     """
     DirNode stores list of files and directories within this node.
     Nodes may be used standalone but within repository context they
     lazily fetch data within same repositorty's changeset.
     """
 
     def __init__(self, path, nodes=(), changeset=None):
         """
         Only one of ``nodes`` and ``changeset`` may be given. Passing both
         would raise ``NodeError`` exception.
 
         :param path: relative path to the node
         :param nodes: content may be passed to constructor
         :param changeset: if given, will use it to lazily fetch content
         :param size: always 0 for ``DirNode``
         """
         if nodes and changeset:
             raise NodeError("Cannot use both nodes and changeset")
         super(DirNode, self).__init__(path, NodeKind.DIR)
         self.changeset = changeset
         self._nodes = nodes
 
     @LazyProperty
     def content(self):
         raise NodeError("%s represents a dir and has no ``content`` attribute"
             % self)
 
     @LazyProperty
     def nodes(self):
         if self.changeset:
             nodes = self.changeset.get_nodes(self.path)
         else:
             nodes = self._nodes
         self._nodes_dict = dict((node.path, node) for node in nodes)
         return sorted(nodes)
 
     @LazyProperty
     def files(self):
         return sorted((node for node in self.nodes if node.is_file()))
 
     @LazyProperty
     def dirs(self):
         return sorted((node for node in self.nodes if node.is_dir()))
 
     def __iter__(self):
         for node in self.nodes:
             yield node
 
     def get_node(self, path):
         """
         Returns node from within this particular ``DirNode``, so it is now
         allowed to fetch, i.e. node located at 'docs/api/index.rst' from node
         'docs'. In order to access deeper nodes one must fetch nodes between
         them first - this would work::
 
            docs = root.get_node('docs')
            docs.get_node('api').get_node('index.rst')
 
         :param: path - relative to the current node
 
         .. note::
            To access lazily (as in example above) node have to be initialized
            with related changeset object - without it node is out of
            context and may know nothing about anything else than nearest
            (located at same level) nodes.
         """
         try:
             path = path.rstrip('/')
             if path == '':
                 raise NodeError("Cannot retrieve node without path")
             self.nodes  # access nodes first in order to set _nodes_dict
             paths = path.split('/')
             if len(paths) == 1:
                 if not self.is_root():
                     path = '/'.join((self.path, paths[0]))
                 else:
                     path = paths[0]
                 return self._nodes_dict[path]
             elif len(paths) > 1:
                 if self.changeset is None:
                     raise NodeError("Cannot access deeper "
                                     "nodes without changeset")
                 else:
                     path1, path2 = paths[0], '/'.join(paths[1:])
                     return self.get_node(path1).get_node(path2)
             else:
                 raise KeyError
         except KeyError:
             raise NodeError("Node does not exist at %s" % path)
 
     @LazyProperty
     def state(self):
         raise NodeError("Cannot access state of DirNode")
 
     @LazyProperty
     def size(self):
         size = 0
         for root, dirs, files in self.changeset.walk(self.path):
             for f in files:
                 size += f.size
 
         return size
 
     def __repr__(self):
         return '<%s %r @ %s>' % (self.__class__.__name__, self.path,
                                  self.changeset.short_id)
 
 
 class RootNode(DirNode):
     """
     DirNode being the root node of the repository.
     """
 
     def __init__(self, nodes=(), changeset=None):
         super(RootNode, self).__init__(path='', nodes=nodes,
             changeset=changeset)
 
     def __repr__(self):
         return '<%s>' % self.__class__.__name__
 
 
 class SubModuleNode(Node):
     """
     represents a SubModule of Git or SubRepo of Mercurial
     """
     is_binary = False
     size = 0
 
     def __init__(self, name, url=None, changeset=None, alias=None):
         self.path = name
         self.kind = NodeKind.SUBMODULE
         self.alias = alias
         # we have to use emptyChangeset here since this can point to svn/git/hg
         # submodules we cannot get from repository
         self.changeset = EmptyChangeset(str(changeset), alias=alias)
         self.url = url or self._extract_submodule_url()
 
     def __repr__(self):
         return '<%s %r @ %s>' % (self.__class__.__name__, self.path,
                                  self.changeset.short_id)
 
     def _extract_submodule_url(self):
         if self.alias == 'git':
             #TODO: find a way to parse gits submodule file and extract the
             # linking URL
             return self.path
         if self.alias == 'hg':
             return self.path
 
     @LazyProperty
     def name(self):
         """
         Returns name of the node so if its path
         then only last part is returned.
         """
         org = safe_unicode(self.path.rstrip('/').split('/')[-1])
         return u'%s @ %s' % (org, self.changeset.short_id)