Completely rewrote the dispatcher in the command system

src/command_system/dispatcher.py

+# Copyright (c) 2010, Alexander Cherniuk (ts33kr@gmail.com)
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# * Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+#
+# * Redistributions in binary form must reproduce the above copyright
+#   notice, this list of conditions and the following disclaimer in the
+#   documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""
+Backbone of the command system. Provides smart and controllable
+dispatching mechanism with an auto-discovery functionality. In addition
+to automatic discovery and dispatching, also features manual control
+over the process.
+"""
+
+from types import NoneType
+from tools import remove
+
+COMMANDS = {}
+CONTAINERS = {}
+
+def add_host(host):
+    CONTAINERS[host] = []
+
+def remove_host(host):
+    remove(CONTAINERS, host)
+
+def add_container(container):
+    for host in container.HOSTS:
+        CONTAINERS[host].append(container)
+
+def remove_container(container):
+    for host in container.HOSTS:
+        remove(CONTAINERS[host], container)
+
+def add_commands(container):
+    commands = COMMANDS.setdefault(container, {})
+    for command in traverse_commands(container):
+        for name in command.names:
+            commands[name] = command
+
+def remove_commands(container):
+    remove(COMMANDS, container)
+
+def traverse_commands(container):
+    for name in dir(container):
+        attribute = getattr(container, name)
+        if is_command(attribute):
+            yield attribute
+
+def is_command(attribute):
+    from framework import Command
+    return isinstance(attribute, Command)
+
+def is_root(namespace):
+    metaclass = namespace.get("__metaclass__", NoneType)
+    return issubclass(metaclass, Dispatchable)
+
+def get_command(host, name):
+    for container in CONTAINERS[host]:
+        command = COMMANDS[container].get(name)
+        if command:
+            return command
+
+def list_commands(host):
+    for container in CONTAINERS[host]:
+        commands = COMMANDS[container]
+        for name, command in commands.iteritems():
+            yield name, command
+
+class Dispatchable(type):
+
+    def __init__(self, name, bases, namespace):
+        parents = super(Dispatchable, self)
+        parents.__init__(name, bases, namespace)
+        if not is_root(namespace):
+            self.dispatch()
+
+    def dispatch(self):
+        if self.AUTOMATIC:
+            self.enable()
+
+class Host(Dispatchable):
+
+    def enable(self):
+        add_host(self)
+
+    def disable(self):
+        remove_host(self)
+
+class Container(Dispatchable):
+
+    def enable(self):
+        add_container(self)
+        add_commands(self)
+
+    def disable(self):
+        remove_commands(self)
+        remove_container(self)
\ No newline at end of file

src/command_system/dispatching.py

-# Copyright (C) 2009-2010  Alexander Cherniuk <ts33kr@gmail.com>
-#
-# 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 3 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, see <http://www.gnu.org/licenses/>.
-
-"""
-The backbone of the command system. Provides automatic dispatching which
-does not require explicit registering commands or containers and remains
-active even after everything is done, so new commands can be added
-during the runtime.
-"""
-
-from types import NoneType
-
-class Dispatcher(type):
-
-    containers = {}
-    commands = {}
-
-    @classmethod
-    def register_host(cls, host):
-        cls.containers[host] = []
-
-    @classmethod
-    def register_container(cls, container):
-        for host in container.HOSTS:
-            cls.containers[host].append(container)
-
-    @classmethod
-    def register_commands(cls, container):
-        cls.commands[container] = {}
-        for command in cls.traverse_commands(container):
-            for name in command.names:
-                cls.commands[container][name] = command
-
-    @classmethod
-    def get_command(cls, host, name):
-        for container in cls.containers[host]:
-            command = cls.commands[container].get(name)
-            if command:
-                return command
-
-    @classmethod
-    def list_commands(cls, host):
-        for container in cls.containers[host]:
-            commands = cls.commands[container]
-            for name, command in commands.iteritems():
-                yield name, command
-
-    @classmethod
-    def traverse_commands(cls, container):
-        for name in dir(container):
-            attribute = getattr(container, name)
-            if cls.is_command(attribute):
-                yield attribute
-
-    @staticmethod
-    def is_root(ns):
-        metaclass = ns.get('__metaclass__', NoneType)
-        return issubclass(metaclass, Dispatcher)
-
-    @staticmethod
-    def is_command(attribute):
-        from framework import Command
-        return isinstance(attribute, Command)
-
-class HostDispatcher(Dispatcher):
-
-    def __init__(self, name, bases, ns):
-        if not Dispatcher.is_root(ns):
-            HostDispatcher.register_host(self)
-        super(HostDispatcher, self).__init__(name, bases, ns)
-
-class ContainerDispatcher(Dispatcher):
-
-    def __init__(self, name, bases, ns):
-        if not Dispatcher.is_root(ns):
-            ContainerDispatcher.register_container(self)
-            ContainerDispatcher.register_commands(self)
-        super(ContainerDispatcher, self).__init__(name, bases, ns)

src/command_system/framework.py

@@ -23,7 +23,8 @@ import re
 from types import FunctionType
 from inspect import getargspec, getdoc
 
-from dispatching import Dispatcher, HostDispatcher, ContainerDispatcher
+from dispatcher import Host, Container
+from dispatcher import get_command, list_commands
 from mapping import parse_arguments, adapt_arguments
 from errors import DefinitionError, CommandError, NoCommandError
 
@@ -32,8 +33,12 @@ class CommandHost(object):
     Command host is a hub between numerous command processors and
     command containers. Aimed to participate in a dispatching process in
     order to provide clean and transparent architecture.
+
+    The AUTOMATIC class variable, which must be defined by a command
+    host, specifies whether the command host should be automatically
+    dispatched and enabled by the dispatcher or not.
     """
-    __metaclass__ = HostDispatcher
+    __metaclass__ = Host
 
 class CommandContainer(object):
     """
@@ -41,11 +46,15 @@ class CommandContainer(object):
     allowing them to be dispatched and proccessed correctly. Each
     command container may be bound to a one or more command hosts.
 
-    Bounding is controlled by the HOSTS variable, which must be defined
-    in the body of the command container. This variable should contain a
-    list of hosts to bound to, as a tuple or list.
+    The AUTOMATIC class variable, which must be defined by a command
+    processor, specifies whether the command processor should be
+    automatically dispatched and enabled by the dispatcher or not.
+
+    Bounding is controlled by the HOSTS class variable, which must be
+    defined by the command container. This variable should contain a
+    sequence of hosts to bound to, as a tuple or list.
     """
-    __metaclass__ = ContainerDispatcher
+    __metaclass__ = Container
 
 class CommandProcessor(object):
     """
@@ -126,13 +135,13 @@ class CommandProcessor(object):
         pass
 
     def get_command(self, name):
-        command = Dispatcher.get_command(self.COMMAND_HOST, name)
+        command = get_command(self.COMMAND_HOST, name)
         if not command:
             raise NoCommandError("Command does not exist", name=name)
         return command
 
     def list_commands(self):
-        commands = Dispatcher.list_commands(self.COMMAND_HOST)
+        commands = list_commands(self.COMMAND_HOST)
         commands = dict(commands)
         return sorted(set(commands.itervalues()))
 

src/command_system/implementation/execute.py

@@ -41,6 +41,7 @@ from ..framework import CommandContainer, command, doc
 from hosts import *
 
 class Execute(CommandContainer):
+    AUTOMATIC = True
     HOSTS = ChatCommands, PrivateChatCommands, GroupChatCommands
 
     DIRECTORY = "~"

src/command_system/implementation/hosts.py

@@ -25,18 +25,18 @@ class ChatCommands(CommandHost):
     This command host is bound to the command processor which processes
     commands from a chat.
     """
-    pass
+    AUTOMATIC = True
 
 class PrivateChatCommands(CommandHost):
     """
     This command host is bound to the command processor which processes
     commands from a private chat.
     """
-    pass
+    AUTOMATIC = True
 
 class GroupChatCommands(CommandHost):
     """
     This command host is bound to the command processor which processes
     commands from a group chat.
     """
-    pass
+    AUTOMATIC = True

src/command_system/implementation/standard.py

@@ -43,6 +43,7 @@ class StandardCommonCommands(CommandContainer):
     to all - chat, private chat, group chat.
     """
 
+    AUTOMATIC = True
     HOSTS = ChatCommands, PrivateChatCommands, GroupChatCommands
 
     @command
@@ -164,6 +165,7 @@ class StandardCommonChatCommands(CommandContainer):
     to a chat and a private chat only.
     """
 
+    AUTOMATIC = True
     HOSTS = ChatCommands, PrivateChatCommands
 
     @command
@@ -221,6 +223,7 @@ class StandardChatCommands(CommandContainer):
     to a chat.
     """
 
+    AUTOMATIC = True
     HOSTS = (ChatCommands,)
 
 class StandardPrivateChatCommands(CommandContainer):
@@ -229,6 +232,7 @@ class StandardPrivateChatCommands(CommandContainer):
     to a private chat.
     """
 
+    AUTOMATIC = True
     HOSTS = (PrivateChatCommands,)
 
 class StandardGroupChatCommands(CommandContainer):
@@ -237,6 +241,7 @@ class StandardGroupChatCommands(CommandContainer):
     to a group chat.
     """
 
+    AUTOMATIC = True
     HOSTS = (GroupChatCommands,)
 
     @command(raw=True)

src/command_system/tools.py

+# Copyright (c) 2010, Alexander Cherniuk (ts33kr@gmail.com)
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# * Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+#
+# * Redistributions in binary form must reproduce the above copyright
+#   notice, this list of conditions and the following disclaimer in the
+#   documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+from types import *
+
+def remove(sequence, target):
+    if isinstance(sequence, ListType):
+        if target in sequence:
+            sequence.remove(target)
+    elif isinstance(sequence, DictType):
+        if target in sequence:
+            del sequence[target]
\ No newline at end of file