Imported Upstream version 3.2.2

[debian/gnuradio] / gr-wxgui / src / python / pubsub.py

diff --git a/gr-wxgui/src/python/pubsub.py b/gr-wxgui/src/python/pubsub.py
new file mode 100644 (file)
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--- /dev/null
+++ b/gr-wxgui/src/python/pubsub.py
@@ -0,0 +1,153 @@
+#!/usr/bin/env python
+#
+# Copyright 2008 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, pkey) = self._proxies[key]
+            p[pkey] = 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, pkey) = self._proxies[key]
+            return p[pkey]
+        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, pkey) = self._proxies[key]
+            p.publish(pkey, 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, pkey) = self._proxies[key]
+            p.subscribe(pkey, subscriber)
+        else:
+            self._subscribers[key].append(subscriber)
+
+    def unpublish(self, key):
+        if self._proxies[key] is not None:
+            (p, pkey) = self._proxies[key]
+            p.unpublish(pkey)
+        else:
+            self._publishers[key] = None
+
+    def unsubscribe(self, key, subscriber):
+        if self._proxies[key] is not None:
+            (p, pkey) = self._proxies[key]
+            p.unsubscribe(pkey, subscriber)
+        else:
+            self._subscribers[key].remove(subscriber)
+
+    def proxy(self, key, p, pkey=None):
+        if not self.has_key(key): self.__missing__(key)
+        if pkey is None: pkey = key
+        self._proxies[key] = (p, pkey)
+
+    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']