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, 2003 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

from Thuban import _

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
        # Iterate over a copy of receivers because the receivers might
        # unsubscribe themselves when receiving a message and Disconnect
        # would modify receivers in place while we're iterating over it.
        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 Conduit(Publisher):

    def _do_forward(self, *args, **kw):
        self.issue(args[-1], *args[:-1], **kw)

    def subscribe_forwarding(self, channel, obj):
        if obj is not None:
            obj.Subscribe(channel, self._do_forward, channel)

    def unsubscribe_forwarding(self, channel, obj):
        if obj is not None:
            obj.Unsubscribe(channel, self._do_forward, channel)

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	bh	1144	# Copyright (C) 1997, 1998, 2000, 2001, 2003 by Bernhard Herzog
7	bh	6	#
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	jan	374	from Thuban import _
32
33	bh	6	class ConnectorError(Exception):
34			pass
35
36			class Connector:
37
38			def __init__(self):
39			self.connections = {}
40
41			def Connect(self, object, channel, function, args):
42			idx = id(object)
43			if self.connections.has_key(idx):
44			channels = self.connections[idx]
45			else:
46			channels = self.connections[idx] = {}
47
48			if channels.has_key(channel):
49			receivers = channels[channel]
50			else:
51			receivers = channels[channel] = []
52
53			info = (function, args)
54			try:
55			receivers.remove(info)
56			except ValueError:
57			pass
58			receivers.append(info)
59
60			def Disconnect(self, object, channel, function, args):
61			try:
62			receivers = self.connections[id(object)][channel]
63			except KeyError:
64			raise ConnectorError, \
65	jan	374	_('no receivers for channel %s of %s') % (channel, object)
66	bh	6	try:
67			receivers.remove((function, args))
68			except ValueError:
69			raise ConnectorError,\
70	jan	374	_('receiver %s%s is not connected to channel %s of %s') \
71	bh	6	% (function, args, channel, object)
72
73			if not receivers:
74			# the list of receivers is empty now, remove the channel
75			channels = self.connections[id(object)]
76			del channels[channel]
77			if not channels:
78			# the object has no more channels
79			del self.connections[id(object)]
80
81			def Issue(self, object, channel, *args):
82			#print object, channel, args
83			try:
84			receivers = self.connections[id(object)][channel]
85			except KeyError:
86			return
87	bh	1144	# Iterate over a copy of receivers because the receivers might
88			# unsubscribe themselves when receiving a message and Disconnect
89			# would modify receivers in place while we're iterating over it.
90			for func, fargs in receivers[:]:
91	bh	6	try:
92			apply(func, args + fargs)
93			except:
94	jan	374	sys.stderr.write(_("Warning: %s.%s: %s%s\n")
95	bh	6	% (object, channel, func, fargs))
96			import traceback
97			traceback.print_exc()
98
99			def RemovePublisher(self, object):
100			i = id(object)
101			if self.connections.has_key(i):
102			del self.connections[i]
103			# don't use try: del ... ; except KeyError here. That would create a
104			# new reference of object in a traceback object and this method should
105			# be callable from a __del__ method (at least for versions prior
106			# Python 1.5)
107
108			def HasSubscribers(self, object):
109			return self.connections.has_key(id(object))
110
111			def print_connections(self):
112			# for debugging
113			for id, channels in self.connections.items():
114			for name, subscribers in channels.items():
115	bh	62	print hex(id), name
116	bh	6	for func, args in subscribers:
117			if type(func) == MethodType:
118	jan	374	print _('\tmethod %s of %s') % (func.im_func.func_name,
119			func.im_self)
120	bh	6	else:
121			print '\t', func
122
123
124
125			_the_connector = Connector()
126
127			Connect = _the_connector.Connect
128			Issue = _the_connector.Issue
129			RemovePublisher = _the_connector.RemovePublisher
130			Disconnect = _the_connector.Disconnect
131			def Subscribe(channel, function, *args):
132			return Connect(None, channel, function, args)
133
134
135			class Publisher:
136
137			def __del__(self):
138			# the new finalization code in 1.5.1 might bind RemovePublisher
139			# to None before all objects derived from Publisher are deleted...
140			if RemovePublisher is not None:
141			RemovePublisher(self)
142
143			def Subscribe(self, channel, func, *args):
144			Connect(self, channel, func, args)
145
146			def Unsubscribe(self, channel, func, *args):
147			Disconnect(self, channel, func, args)
148
149			def issue(self, channel, *args):
150			apply(Issue, (self, channel,) + args)
151
152			def Destroy(self):
153			RemovePublisher(self)
154	bh	1778
155
156			class Conduit(Publisher):
157
158			def _do_forward(self, args, *kw):
159			self.issue(args[-1], args[:-1], *kw)
160
161			def subscribe_forwarding(self, channel, obj):
162			if obj is not None:
163			obj.Subscribe(channel, self._do_forward, channel)
164
165			def unsubscribe_forwarding(self, channel, obj):
166			if obj is not None:
167			obj.Unsubscribe(channel, self._do_forward, channel)
168
Name	Value
svn:eol-style	native
svn:keywords	Author Date Id Revision