Thuban/Lib/connector.py

# This module was copied almost verbatim from Sketch. The only change is
# the base class of ConnectorError which was a Sketch specific exception
# class. 

# Sketch - A Python-based interactive drawing program
# Copyright (C) 1997, 1998, 2000, 2001 by Bernhard Herzog
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Library General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library 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
# Library General Public License for more details.
#
# You should have received a copy of the GNU Library General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

__version__ = "$Revision$"

#
#       The Connector
#

import sys
from types import MethodType

class ConnectorError(Exception):
    pass

class Connector:

    def __init__(self):
        self.connections = {}

    def Connect(self, object, channel, function, args):
        idx = id(object)
        if self.connections.has_key(idx):
            channels = self.connections[idx]
        else:
            channels = self.connections[idx] = {}

        if channels.has_key(channel):
            receivers = channels[channel]
        else:
            receivers = channels[channel] = []

        info = (function, args)
        try:
            receivers.remove(info)
        except ValueError:
            pass
        receivers.append(info)

    def Disconnect(self, object, channel, function, args):
        try:
            receivers = self.connections[id(object)][channel]
        except KeyError:
            raise ConnectorError, \
                  'no receivers for channel %s of %s' % (channel, object)
        try:
            receivers.remove((function, args))
        except ValueError:
            raise ConnectorError,\
            'receiver %s%s is not connected to channel %s of %s' \
            % (function, args, channel, object)

        if not receivers:
            # the list of receivers is empty now, remove the channel
            channels = self.connections[id(object)]
            del channels[channel]
            if not channels:
                # the object has no more channels
                del self.connections[id(object)]

    def Issue(self, object, channel, *args):
        #print object, channel, args
        try:
            receivers = self.connections[id(object)][channel]
        except KeyError:
            return
        for func, fargs in receivers:
            try:
                apply(func, args + fargs)
            except:
                sys.stderr.write("Warning: %s.%s: %s%s\n"
                                 % (object, channel, func, fargs))
                import traceback
                traceback.print_exc()

    def RemovePublisher(self, object):
        i = id(object)
        if self.connections.has_key(i):
            del self.connections[i]
        # don't use try: del ... ; except KeyError here. That would create a
        # new reference of object in a traceback object and this method should
        # be callable from a __del__ method (at least for versions prior
        # Python 1.5)

    def HasSubscribers(self, object):
        return self.connections.has_key(id(object))

    def print_connections(self):
        # for debugging
        for id, channels in self.connections.items():
            for name, subscribers in channels.items():
                print hex(id), name
                for func, args in subscribers:
                    if type(func) == MethodType:
                        print '\tmethod %s of %s' % (func.im_func.func_name,
                                                     func.im_self)
                    else:
                        print '\t', func


_the_connector = Connector()

Connect = _the_connector.Connect
Issue = _the_connector.Issue
RemovePublisher = _the_connector.RemovePublisher
Disconnect = _the_connector.Disconnect
def Subscribe(channel, function, *args):
    return Connect(None, channel, function, args)


class Publisher:

    def __del__(self):
        # the new finalization code in 1.5.1 might bind RemovePublisher
        # to None before all objects derived from Publisher are deleted...
        if RemovePublisher is not None:
            RemovePublisher(self)

    def Subscribe(self, channel, func, *args):
        Connect(self, channel, func, args)

    def Unsubscribe(self, channel, func, *args):
        Disconnect(self, channel, func, args)

    def issue(self, channel, *args):
        apply(Issue, (self, channel,) + args)

    def Destroy(self):
        RemovePublisher(self)


class QueueingPublisher(Publisher):

    def __init__(self):
        self.clear_message_queue()

    def queue_message(self, channel, *args):
        # Put message in the queue. If it is already queued put it at
        # the end. This is done to make certain that no channel gets
        # called twice between two calls to flush_message_queue. If the
        # order of channel invocation is important two or more queues
        # should be used.
        message = (channel, args)
        if message not in self.message_queue:
            self.message_queue.append(message)

    def flush_message_queue(self):
        # Issue all queued messages and make the queue empty
        #
        # Issueing messages might result in new messages being queued.
        # This does not happen in sketch yet (Jul 1997) but let's hope
        # that we don't get infinite loops here...
        while self.message_queue:
            queue = self.message_queue
            self.message_queue = []
            for channel, args in queue:
                apply(Issue, (self, channel) + args)

    def clear_message_queue(self):
        self.message_queue = []

1	bh	6	# This module was copied almost verbatim from Sketch. The only change is
2			# the base class of ConnectorError which was a Sketch specific exception
3			# class.
4
5			# Sketch - A Python-based interactive drawing program
6			# Copyright (C) 1997, 1998, 2000, 2001 by Bernhard Herzog
7			#
8			# This library is free software; you can redistribute it and/or
9			# modify it under the terms of the GNU Library General Public
10			# License as published by the Free Software Foundation; either
11			# version 2 of the License, or (at your option) any later version.
12			#
13			# This library is distributed in the hope that it will be useful,
14			# but WITHOUT ANY WARRANTY; without even the implied warranty of
15			# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16			# Library General Public License for more details.
17			#
18			# You should have received a copy of the GNU Library General Public
19			# License along with this library; if not, write to the Free Software
20			# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21
22			__version__ = "$Revision$"
23
24			#
25			# The Connector
26			#
27
28			import sys
29			from types import MethodType
30
31			class ConnectorError(Exception):
32			pass
33
34			class Connector:
35
36			def __init__(self):
37			self.connections = {}
38
39			def Connect(self, object, channel, function, args):
40			idx = id(object)
41			if self.connections.has_key(idx):
42			channels = self.connections[idx]
43			else:
44			channels = self.connections[idx] = {}
45
46			if channels.has_key(channel):
47			receivers = channels[channel]
48			else:
49			receivers = channels[channel] = []
50
51			info = (function, args)
52			try:
53			receivers.remove(info)
54			except ValueError:
55			pass
56			receivers.append(info)
57
58			def Disconnect(self, object, channel, function, args):
59			try:
60			receivers = self.connections[id(object)][channel]
61			except KeyError:
62			raise ConnectorError, \
63			'no receivers for channel %s of %s' % (channel, object)
64			try:
65			receivers.remove((function, args))
66			except ValueError:
67			raise ConnectorError,\
68			'receiver %s%s is not connected to channel %s of %s' \
69			% (function, args, channel, object)
70
71			if not receivers:
72			# the list of receivers is empty now, remove the channel
73			channels = self.connections[id(object)]
74			del channels[channel]
75			if not channels:
76			# the object has no more channels
77			del self.connections[id(object)]
78
79			def Issue(self, object, channel, *args):
80			#print object, channel, args
81			try:
82			receivers = self.connections[id(object)][channel]
83			except KeyError:
84			return
85			for func, fargs in receivers:
86			try:
87			apply(func, args + fargs)
88			except:
89			sys.stderr.write("Warning: %s.%s: %s%s\n"
90			% (object, channel, func, fargs))
91			import traceback
92			traceback.print_exc()
93
94			def RemovePublisher(self, object):
95			i = id(object)
96			if self.connections.has_key(i):
97			del self.connections[i]
98			# don't use try: del ... ; except KeyError here. That would create a
99			# new reference of object in a traceback object and this method should
100			# be callable from a __del__ method (at least for versions prior
101			# Python 1.5)
102
103			def HasSubscribers(self, object):
104			return self.connections.has_key(id(object))
105
106			def print_connections(self):
107			# for debugging
108			for id, channels in self.connections.items():
109			for name, subscribers in channels.items():
110	bh	62	print hex(id), name
111	bh	6	for func, args in subscribers:
112			if type(func) == MethodType:
113			print '\tmethod %s of %s' % (func.im_func.func_name,
114			func.im_self)
115			else:
116			print '\t', func
117
118
119
120			_the_connector = Connector()
121
122			Connect = _the_connector.Connect
123			Issue = _the_connector.Issue
124			RemovePublisher = _the_connector.RemovePublisher
125			Disconnect = _the_connector.Disconnect
126			def Subscribe(channel, function, *args):
127			return Connect(None, channel, function, args)
128
129
130			class Publisher:
131
132			def __del__(self):
133			# the new finalization code in 1.5.1 might bind RemovePublisher
134			# to None before all objects derived from Publisher are deleted...
135			if RemovePublisher is not None:
136			RemovePublisher(self)
137
138			def Subscribe(self, channel, func, *args):
139			Connect(self, channel, func, args)
140
141			def Unsubscribe(self, channel, func, *args):
142			Disconnect(self, channel, func, args)
143
144			def issue(self, channel, *args):
145			apply(Issue, (self, channel,) + args)
146
147			def Destroy(self):
148			RemovePublisher(self)
149
150
151			class QueueingPublisher(Publisher):
152
153			def __init__(self):
154			self.clear_message_queue()
155
156			def queue_message(self, channel, *args):
157			# Put message in the queue. If it is already queued put it at
158			# the end. This is done to make certain that no channel gets
159			# called twice between two calls to flush_message_queue. If the
160			# order of channel invocation is important two or more queues
161			# should be used.
162			message = (channel, args)
163			if message not in self.message_queue:
164			self.message_queue.append(message)
165
166			def flush_message_queue(self):
167			# Issue all queued messages and make the queue empty
168			#
169			# Issueing messages might result in new messages being queued.
170			# This does not happen in sketch yet (Jul 1997) but let's hope
171			# that we don't get infinite loops here...
172			while self.message_queue:
173			queue = self.message_queue
174			self.message_queue = []
175			for channel, args in queue:
176			apply(Issue, (self, channel) + args)
177
178			def clear_message_queue(self):
179			self.message_queue = []
180
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svn:keywords	Author Date Id Revision