Welcome, guest | Sign In | My Account | Store | Cart
import gobject

# Infrastructure: tasks and jobs.

def task(function, *args):
    """Wrapps a task function (expected signature 'function(return_task, [args])'"""
    return function, args

def start_job(generator):
    """Start a job (a generator that yield tasks)."""
    def _next(result):
        def _callback():
            try:
                fun, args = generator.send(result)
            except StopIteration:
                return
            fun(_next, *args)
        # 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):
        x = function(*args, **kwargs)
        queue.put(x)
    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

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

def basso_continuo():
    import sys
    sys.stderr.write(".")
    return True
          
gobject.threads_init()      
start_job(myjob(1, 2))
start_job(myjob(3, 4))
start_job(myjob(5, 6))
gobject.timeout_add(100, basso_continuo)
loop = gobject.MainLoop()
loop.run()

Diff to Previous Revision

--- revision 6 2010-03-26 16:15:52
+++ revision 7 2010-03-26 16:23:30
@@ -24,26 +24,26 @@
 
 def sleep(task_return, seconds):
     """Wait 'seconds' seconds. Returns nothing."""
-    def callback():
+    def _callback():
         task_return(None)
-    gobject.timeout_add(int(seconds * 1000), callback)
+    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):
+    def _thread(queue):
         x = function(*args, **kwargs)
         queue.put(x)
-    def receiver(queue):
+    def _receiver(queue):
         if queue.empty():
             return True
         task_return(queue.get())
     queue = Queue()
-    thread = Thread(target=thread, args=(queue,))
+    thread = Thread(target=_thread, args=(queue,))
     thread.setDaemon(True)
     thread.start()
-    gobject.timeout_add(100, receiver, queue) # poll queue every 0.1 seconds
+    gobject.timeout_add(100, _receiver, queue) # poll queue every 0.1 seconds
 
 # Job example
 

History