~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2007, 2008 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""Support for plugin hooking logic."""

from bzrlib.lazy_import import lazy_import

from bzrlib.symbol_versioning import deprecated_method, one_five

lazy_import(globals(), """

from bzrlib import (

        errors,

        )

""")

class Hooks(dict):

    """A dictionary mapping hook name to a list of callables.

    e.g. ['FOO'] Is the list of items to be called when the

    FOO hook is triggered.

    """

    def __init__(self):

        dict.__init__(self)

        self._callable_names = {}

    def get_hook_name(self, a_callable):

        """Get the name for a_callable for UI display.

        If no name has been registered, the string 'No hook name' is returned.

        We use a fixed string rather than repr or the callables module because

        the code names are rarely meaningful for end users and this is not

        intended for debugging.

        """

        return self._callable_names.get(a_callable, "No hook name")

    @deprecated_method(one_five)

    def install_hook(self, hook_name, a_callable):

        """Install a_callable in to the hook hook_name.

        :param hook_name: A hook name. See the __init__ method of BranchHooks

            for the complete list of hooks.

        :param a_callable: The callable to be invoked when the hook triggers.

            The exact signature will depend on the hook - see the __init__

            method of BranchHooks for details on each hook.

        """

        self.install_named_hook(hook_name, a_callable, None)

    def install_named_hook(self, hook_name, a_callable, name):

        """Install a_callable in to the hook hook_name, and label it name.

        :param hook_name: A hook name. See the __init__ method of BranchHooks

            for the complete list of hooks.

        :param a_callable: The callable to be invoked when the hook triggers.

            The exact signature will depend on the hook - see the __init__

            method of BranchHooks for details on each hook.

        :param name: A name to associate a_callable with, to show users what is

            running.

        """

        try:

            self[hook_name].append(a_callable)

        except KeyError:

            raise errors.UnknownHook(self.__class__.__name__, hook_name)

        if name is not None:

            self.name_hook(a_callable, name)

    def name_hook(self, a_callable, name):

        """Associate name with a_callable to show users what is running."""

        self._callable_names[a_callable] = name