1 files changed, 139 insertions, 0 deletions
diff --git a/qpid/python/qpid/selector.py b/qpid/python/qpid/selector.py
new file mode 100644
index 0000000000..ca5946c3f9
--- /dev/null
+++ b/qpid/python/qpid/selector.py
@@ -0,0 +1,139 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+# 
+#   http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+import atexit, time
+from compat import select, set, selectable_waiter
+from threading import Thread, Lock
+
+class Acceptor:
+
+  def __init__(self, sock, handler):
+    self.sock = sock
+    self.handler = handler
+
+  def fileno(self):
+    return self.sock.fileno()
+
+  def reading(self):
+    return True
+
+  def writing(self):
+    return False
+
+  def readable(self):
+    sock, addr = self.sock.accept()
+    self.handler(sock)
+
+class Selector:
+
+  lock = Lock()
+  DEFAULT = None
+
+  @staticmethod
+  def default():
+    Selector.lock.acquire()
+    try:
+      if Selector.DEFAULT is None:
+        sel = Selector()
+        atexit.register(sel.stop)
+        sel.start()
+        Selector.DEFAULT = sel
+      return Selector.DEFAULT
+    finally:
+      Selector.lock.release()
+
+  def __init__(self):
+    self.selectables = set()
+    self.reading = set()
+    self.writing = set()
+    self.waiter = selectable_waiter()
+    self.reading.add(self.waiter)
+    self.stopped = False
+    self.thread = None
+
+  def wakeup(self):
+    self.waiter.wakeup()
+
+  def register(self, selectable):
+    self.selectables.add(selectable)
+    self.modify(selectable)
+
+  def _update(self, selectable):
+    if selectable.reading():
+      self.reading.add(selectable)
+    else:
+      self.reading.discard(selectable)
+    if selectable.writing():
+      self.writing.add(selectable)
+    else:
+      self.writing.discard(selectable)
+    return selectable.timing()
+
+  def modify(self, selectable):
+    self._update(selectable)
+    self.wakeup()
+
+  def unregister(self, selectable):
+    self.reading.discard(selectable)
+    self.writing.discard(selectable)
+    self.selectables.discard(selectable)
+    self.wakeup()
+
+  def start(self):
+    self.stopped = False
+    self.thread = Thread(target=self.run)
+    self.thread.setDaemon(True)
+    self.thread.start();
+
+  def run(self):
+    while not self.stopped:
+      wakeup = None
+      for sel in self.selectables.copy():
+        t = self._update(sel)
+        if t is not None:
+          if wakeup is None:
+            wakeup = t
+          else:
+            wakeup = min(wakeup, t)
+
+      if wakeup is None:
+        timeout = None
+      else:
+        timeout = max(0, wakeup - time.time())
+
+      rd, wr, ex = select(self.reading, self.writing, (), timeout)
+
+      for sel in wr:
+        if sel.writing():
+          sel.writeable()
+
+      for sel in rd:
+        if sel.reading():
+          sel.readable()
+
+      now = time.time()
+      for sel in self.selectables.copy():
+        w = sel.timing()
+        if w is not None and now > w:
+          sel.timeout()
+
+  def stop(self, timeout=None):
+    self.stopped = True
+    self.wakeup()
+    self.thread.join(timeout)
+    self.thread = None