return NodeState.NOT_CHANGED

    @property

    def is_binary(self):

        """

        Returns True if file has binary content.

        """

        _bin = '\0' in self._get_content()

        return _bin

    def is_browser_compatible_image(self):

        return self.mimetype in [

            "image/gif",

            "image/jpeg",

            "image/png",

            "image/bmp"

        ]

    @LazyProperty

    def extension(self):

        """Returns filenode extension"""

        return self.name.split('.')[-1]

    @property

    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,

                                 getattr(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 repository'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,

                                 getattr(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

        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)

    def __repr__(self):

        return '<%s %r @ %s>' % (self.__class__.__name__, self.path,

                                 getattr(self.changeset, 'short_id', ''))

    @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)