Initial Release of IGNCore version 2.5

core/fifo_queue.py

@@ -0,0 +1,38 @@
+import time
+from queue import Queue
+
+
+class FifoQueue(Queue):
+    def get_or_default(self, block=True, timeout=None, default=None):
+        """Remove and return an item from the queue.
+
+        This differs from get() in that it will return `default` instead of
+        raising Empty exception.
+
+        If optional args 'block' is true and 'timeout' is None (the default),
+        block if necessary until an item is available. If 'timeout' is
+        a non-negative number, it blocks at most 'timeout' seconds and raises
+        the Empty exception if no item was available within that time.
+        Otherwise ('block' is false), return an item if one is immediately
+        available, else raise the Empty exception ('timeout' is ignored
+        in that case).
+        """
+        with self.not_empty:
+            if not block:
+                if not self._qsize():
+                    return default
+            elif timeout is None:
+                while not self._qsize():
+                    self.not_empty.wait()
+            elif timeout < 0:
+                raise ValueError("'timeout' must be a non-negative number")
+            else:
+                endtime = time.time() + timeout
+                while not self._qsize():
+                    remaining = endtime - time.time()
+                    if remaining <= 0.0:
+                        return default
+                    self.not_empty.wait(remaining)
+            item = self._get()
+            self.not_full.notify()
+            return item