Object processor queue class

Previous commit didn't include the class. This class takes care of queue
size monitoring so that the system doesn't run out of memory.

src/class_objectProcessorQueue.py

@@ -0,0 +1,28 @@
+import shared
+
+import Queue
+import threading
+import time
+
+class ObjectProcessorQueue(Queue.Queue):
+    maxSize = 32000000
+
+    def __init__(self):
+        Queue.Queue.__init__(self)
+        self.sizeLock = threading.Lock()
+        self.curSize = 0 # in Bytes. We maintain this to prevent nodes from flooing us with objects which take up too much memory. If this gets too big we'll sleep before asking for further objects.
+
+    def put(self, item, block = True, timeout = None):
+        while self.curSize >= self.maxSize and not shared.shutdown:
+            time.sleep(1)
+        if shared.shutdown:
+            return
+        with self.sizeLock:
+            self.curSize += len(item[1])
+        Queue.Queue.put(self, item, block, timeout)
+
+    def get(self, block = True, timeout = None):
+        item = Queue.Queue.get(self, block, timeout)
+        with self.sizeLock:
+            self.curSize -= len(item[1])
+        return item