Added the thread management objects

mitterlib/ui/ui_pygtk.py

@@ -23,6 +23,8 @@ import gobject
 gobject.threads_init()
 
 import logging
+import threading
+import Queue
 
 from mitterlib.ui.helpers.image_helpers import find_image
 
@@ -35,6 +37,107 @@ from mitterlib.ui.helpers.image_helpers import find_image
 
 _log = logging.getLogger('ui.pygtk')
 
+# ----------------------------------------------------------------------
+# Threading related objects.
+# These classes are based on the code available at http://gist.github.com/51686
+# (c) 2008, John Stowers <john.stowers@gmail.com>
+# ----------------------------------------------------------------------
+
+class _IdleObject(gobject.GObject):
+    """
+    Override gobject.GObject to always emit signals in the main thread
+    by emmitting on an idle handler
+    """
+    def __init__(self):
+        gobject.GObject.__init__(self)
+ 
+    def emit(self, *args):
+        gobject.idle_add(gobject.GObject.emit,self,*args)
+
+
+class _WorkerThread(threading.Thread, _IdleObject):
+    """
+    A single working thread.
+    """
+    __gsignals__ = {
+            "completed": (
+                gobject.SIGNAL_RUN_LAST, gobject.TYPE_NONE, [
+                    gobject.TYPE_PYOBJECT]),    # The list/NetworkData object
+            "exception": (
+                gobject.SIGNAL_RUN_LAST, gobject.TYPE_NONE, [
+                    gobject.TYPE_PYOBJECT])     # The exception
+            }
+ 
+    def __init__(self, queue):
+        threading.Thread.__init__(self)
+        _IdleObject.__init__(self)
+        self._queue = queue
+ 
+    def run(self):
+        while True:
+            _log.debug('Thread %d waiting for work', self.get_ident())
+            work = self._queue.get()
+            if work is None:
+                # End the thread
+                break
+
+            # call the function
+            _log.debug('Thread %s got work', self.get_ident())
+            (complete, exception, function, args, kwargs) = work
+
+            _log.debug('Calling %s', str(function))
+
+            try:
+                result = function(*args, **kwargs)
+            except Exception, exc:  # Catch ALL exceptions
+                # XXX: Check if this catch all warnins too!
+                _log.debug('Exception %s', str(exc))
+                self.emit("exception", exc)
+
+            self.emit("completed", result)
+
+            # work complete
+            self._queue.task_done()
+
+        _log.debug('Thread %d ending', self.get_ident())
+        return
+
+
+class _ThreadManager(object):
+    """Manages the threads."""
+
+    def __init__(self, pool_size=2):
+        """Start the thread pool. The number of threads in the pool is defined
+        by `pool_size`, defaults to 2."""
+        self._queue = Queue.Queue()
+        self._thread_pool = []
+
+        while pool_size > 0:
+            _log.debug('Starting thread %d', pool_size)
+            new_thread = _WorkerThread(self._queue)
+            new_thread.start()
+            self._thread_pool.append(new_thread)
+            pool_size -= 1
+
+        _log.debug('All threads started')
+        return
+
+    def add_work(self, complete_cb, exception_cb, func, *args, **kwargs):
+        """Add a work to the thread list. `complete_cb` is the function to be
+        called with the result of the work. `exception_cb` is the function to
+        be called if there are any exceptions raised. Note that, once the
+        work is complete, one of those will be called, not both. `func` is the
+        function to be called in the secondary threads. `args` and `kwargs`
+        are parameters passed to the function."""
+
+        # wrap all the params in a nice tuple to be added to the queue.
+        work = (complete_cb, exception_cb, func, args, kwargs)
+        self._queue.put(work)
+        return
+
+# ----------------------------------------------------------------------
+# Mitter interface object
+# ----------------------------------------------------------------------
 
 class Interface(object):
     """Linux/GTK interface for Mitter."""