experimental stuff: Deferring proxies...

git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@1908 fd906abe-77d9-0310-91a1-e0d9ade77398

twisted/deferring.py

@@ -0,0 +1,72 @@
+#
+#  Copyright (c) 2007 Helmut Merz helmutm@cy55.de
+#
+#  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 2 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, write to the Free Software
+#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+
+"""
+Objects that defer attribute access.
+
+$Id$
+"""
+
+from twisted.internet import reactor
+from twisted.internet.defer import Deferred
+
+
+class Deferring(Deferred):
+
+    def __init__(self, context):
+        self.context = context
+        Deferred.__init__(self)
+
+    def __getattr__(self, attr):
+        d = Deferring(self)
+        reactor.callLater(0, d.getattr, self, attr)
+        return d
+
+    def __call__(self, *args, **kw):
+        d = Deferring(None)
+        reactor.callLater(0, d.call, self, *args, **kw)
+        return d
+
+    def __repr__(self):
+        return '<Deferring on %s>' % repr(self.context)
+
+    __str__ = __repr__
+
+    def makeCallback(self, method, *args, **kw):
+        #print '*** makeCallback', self, method, args, kw
+        def cb(result, method=method, args=args, kw=kw):
+            value = method(result, *args, **kw)
+            #print '*** cb', self, result, method, args, kw, value
+            self.callback(value)
+        return cb
+
+    def getattr(self, deferring, attr):
+        ctx = deferring.context
+        if isinstance(ctx, Deferring):
+            ctx.addCallback(self.makeCallback(self.getattr, attr))
+        else:
+            value = getattr(deferring.context, attr)
+            self.context = value
+            self.callback(value)
+
+    def call(self, deferring, *args, **kw):
+        ctx = deferring.context
+        value = ctx(*args, **kw)
+        self.context = value
+        self.callback(value)
+

twisted/deferring.txt

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+======================
+Working with Deferreds
+======================
+
+$Id$
+
+  >>> from cybertools.twisted.tests import tester
+
+  >>> from cybertools.twisted.deferring import Deferring
+
+  >>> class Demo(object):
+  ...     color = 'green'
+
+  >>> class Demo2(object):
+  ...     color = 'red'
+  ...     other = Demo()
+
+  >>> demo = Demo()
+  >>> demoDef = Deferring(demo)
+  >>> col = demoDef.color
+  >>> col
+  <Deferring on ...>
+  >>> print col
+  <Deferring on ...>
+
+  >>> def printIt(result):
+  ...     print 'result:', str(result)
+
+  >>> col.addCallback(printIt)
+  <Deferring on ...>
+
+  >>> tester.iterate()
+  result: green
+  >>> col
+  <Deferring on 'green'>
+
+  >>> demo2 = Demo2()
+  >>> demo2Def = Deferring(demo2)
+  >>> other = demo2Def.other
+  >>> other
+  <Deferring on <Deferring on ...>>
+
+  >>> ocol = other.color
+
+  >>> ocol.addCallback(printIt)
+  <Deferring on ...>
+
+  >>> tester.iterate()
+  result: green
+
+  >>> ocol
+  <Deferring on 'green'>
+
+  >>> other
+  <Deferring on <Demo object ...>>

twisted/tests.py

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+# $Id$
+
+import unittest
+import doctest
+from twisted.internet import reactor
+
+import cybertools.twisted.deferring
+
+
+class Tester(object):
+
+    def iterate(self, n=10, delays={}):
+        for i in range(n):
+            delay = delays.get(i, 0)
+            reactor.iterate(delay)
+
+tester = Tester()
+
+
+class Test(unittest.TestCase):
+    "Basic tests for modules in the util package."
+
+    def testBasicStuff(self):
+        pass
+
+
+def test_suite():
+    flags = doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS
+    return unittest.TestSuite((
+        #unittest.makeSuite(Test),  # we don't need this
+        #doctest.DocTestSuite(cybertools.util.property, optionflags=flags),
+        doctest.DocFileSuite('deferring.txt', optionflags=flags),
+        ))
+
+if __name__ == '__main__':
+    unittest.main(defaultTest='test_suite')