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import gobject

# Infrastructure: tasks and jobs.

def task(fun, *args, **kwargs):
    """Wraps a task (expected signature: 'def fun(task_return, [args], [kwargs])'"""
    return fun, args, kwargs

def start_job(generator):
    """Start a job (a generator that yield tasks)."""
    def _next(result):
        def _callback():
            try:
                fun, args, kwargs = generator.send(result)
            except StopIteration:
                return
            fun(_next, *args, **kwargs)
        # isolate the advance of the coroutine to another gobject loop
        gobject.idle_add(_callback)            
    _next(None)    

# Tasks: A task is a normal function, except for the first argument, a function
#        that must be called with the result of the task.

def sleep(task_return, seconds):
    """Wait 'seconds' seconds. Returns nothing."""
    def _callback():
        task_return(None)
    gobject.timeout_add(int(seconds * 1000), _callback)

def threaded(task_return, function, *args, **kwargs):
    """Run function(*args, **kwargs) in a thread and return the value."""
    from Queue import Queue
    from threading import Thread
    def _thread(queue):
        queue.put(function(*args, **kwargs))
    def _receiver(queue):
        if queue.empty():
            return True
        task_return(queue.get())
    queue = Queue()
    thread = Thread(target=_thread, args=(queue,))
    thread.setDaemon(True)
    thread.start()
    gobject.timeout_add(100, _receiver, queue) # poll queue every 0.1 seconds

# Job example

import sys
import time
import random

def heavy_function(a, b):
    time.sleep(1.0)
    return a + b
        
def myjob(a, b):
    yield task(sleep, random.uniform(1.0, 3.0))
    result = yield task(threaded, heavy_function, a, b)
    print result

def basso_continuo():
    sys.stderr.write(".")
    return True
          
gobject.threads_init()
for x in range(1, 11):      
    start_job(myjob(3*x, 7*x))
gobject.timeout_add(100, basso_continuo)
loop = gobject.MainLoop()
loop.run()

Diff to Previous Revision

--- revision 9 2010-03-26 16:38:41
+++ revision 10 2010-03-27 18:51:34
@@ -33,8 +33,7 @@
     from Queue import Queue
     from threading import Thread
     def _thread(queue):
-        x = function(*args, **kwargs)
-        queue.put(x)
+        queue.put(function(*args, **kwargs))
     def _receiver(queue):
         if queue.empty():
             return True

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