Copy pubsub from gr-wxgui into gnuradio-core, need to migrate wxgui usage to new class before removing old

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@10575 221aa14e-8319-0410-a670-987f0aec2ac5

2 files changed, 155 insertions, 1 deletions

diff --git a/gnuradio-core/src/python/gnuradio/gr/Makefile.am b/gnuradio-core/src/python/gnuradio/gr/Makefile.am
index 31d8831fa..41ef52240 100644
--- a/gnuradio-core/src/python/gnuradio/gr/Makefile.am
+++ b/gnuradio-core/src/python/gnuradio/gr/Makefile.am
@@ -40,7 +40,8 @@ grgrpython_PYTHON = 		\
 	hier_block2.py		\
 	prefs.py		\
 	scheduler.py		\
-	top_block.py
+	top_block.py		\
+	pubsub.py
 
 noinst_PYTHON = 			\
 	benchmark_filters.py		\
diff --git a/gnuradio-core/src/python/gnuradio/gr/pubsub.py b/gnuradio-core/src/python/gnuradio/gr/pubsub.py
new file mode 100644
index 000000000..8fb7a8519
--- /dev/null
+++ b/gnuradio-core/src/python/gnuradio/gr/pubsub.py
@@ -0,0 +1,153 @@
+#!/usr/bin/env python
+#
+# Copyright 2008,2009 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# GNU Radio 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, or (at your option)
+# any later version.
+#
+# GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+"""
+Abstract GNU Radio publisher/subscriber interface
+
+This is a proof of concept implementation, will likely change significantly.
+"""
+
+class pubsub(dict):
+    def __init__(self):
+	self._publishers = { }
+	self._subscribers = { }
+	self._proxies = { }
+	
+    def __missing__(self, key, value=None):
+	dict.__setitem__(self, key, value)
+	self._publishers[key] = None
+	self._subscribers[key] = []
+	self._proxies[key] = None
+	
+    def __setitem__(self, key, val):
+	if not self.has_key(key): 
+	    self.__missing__(key, val)
+	elif self._proxies[key] is not None:
+	    (p, newkey) = self._proxies[key]
+	    p[newkey] = val
+	else:
+	    dict.__setitem__(self, key, val)
+	for sub in self._subscribers[key]:
+	    # Note this means subscribers will get called in the thread
+	    # context of the 'set' caller.
+	    sub(val)
+
+    def __getitem__(self, key):
+	if not self.has_key(key): self.__missing__(key)
+	if self._proxies[key] is not None:
+	    (p, newkey) = self._proxies[key]
+	    return p[newkey]
+	elif self._publishers[key] is not None:
+	    return self._publishers[key]()
+	else:
+	    return dict.__getitem__(self, key)
+
+    def publish(self, key, publisher):
+	if not self.has_key(key): self.__missing__(key)
+        if self._proxies[key] is not None:
+            (p, newkey) = self._proxies[key]
+            p.publish(newkey, publisher)
+        else:
+            self._publishers[key] = publisher
+	
+    def subscribe(self, key, subscriber):
+	if not self.has_key(key): self.__missing__(key)
+        if self._proxies[key] is not None:
+            (p, newkey) = self._proxies[key]
+            p.subscribe(newkey, subscriber)
+        else:
+            self._subscribers[key].append(subscriber)
+	
+    def unpublish(self, key):
+        if self._proxies[key] is not None:
+            (p, newkey) = self._proxies[key]
+            p.unpublish(newkey)
+        else:
+            self._publishers[key] = None
+	
+    def unsubscribe(self, key, subscriber):
+        if self._proxies[key] is not None:
+            (p, newkey) = self._proxies[key]
+            p.unsubscribe(newkey, subscriber)
+        else:
+            self._subscribers[key].remove(subscriber)
+
+    def proxy(self, key, p, newkey=None):
+	if not self.has_key(key): self.__missing__(key)
+	if newkey is None: newkey = key
+	self._proxies[key] = (p, newkey)	
+
+    def unproxy(self, key):
+        self._proxies[key] = None
+
+# Test code
+if __name__ == "__main__":
+    import sys
+    o = pubsub()
+
+    # Non-existent key gets auto-created with None value
+    print "Auto-created key 'foo' value:", o['foo']
+
+    # Add some subscribers
+    # First is a bare function
+    def print_len(x):
+	print "len=%i" % (len(x), )
+    o.subscribe('foo', print_len)
+
+    # The second is a class member function
+    class subber(object):
+	def __init__(self, param):
+	    self._param = param
+	def printer(self, x):
+	    print self._param, `x`
+    s = subber('param')
+    o.subscribe('foo', s.printer)
+
+    # The third is a lambda function
+    o.subscribe('foo', lambda x: sys.stdout.write('val='+`x`+'\n'))
+
+    # Update key 'foo', will notify subscribers    
+    print "Updating 'foo' with three subscribers:"
+    o['foo'] = 'bar';
+
+    # Remove first subscriber
+    o.unsubscribe('foo', print_len)
+
+    # Update now will only trigger second and third subscriber
+    print "Updating 'foo' after removing a subscriber:"
+    o['foo'] = 'bar2';
+    
+    # Publish a key as a function, in this case, a lambda function
+    o.publish('baz', lambda : 42)
+    print "Published value of 'baz':", o['baz']
+
+    # Unpublish the key
+    o.unpublish('baz')
+
+    # This will return None, as there is no publisher
+    print "Value of 'baz' with no publisher:", o['baz']
+    
+    # Set 'baz' key, it gets cached
+    o['baz'] = 'bazzz'
+
+    # Now will return cached value, since no provider
+    print "Cached value of 'baz' after being set:", o['baz']