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+#ifndef _sys_DispatchHandle_h
+#define _sys_DispatchHandle_h
+
+/*
+ *
+ * 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.
+ *
+ */
+
+#include "qpid/sys/Poller.h"
+#include "qpid/sys/Mutex.h"
+#include "qpid/CommonImportExport.h"
+#include <boost/function.hpp>
+
+#include <queue>
+
+namespace qpid {
+namespace sys {
+
+class DispatchHandleRef;
+/**
+ * In order to have your own handle (file descriptor on Unix) watched by the poller
+ * you need to:
+ *
+ * - Subclass IOHandle, in the constructor supply an appropriate
+ * IOHandlerPrivate object for the platform.
+ *
+ * - Construct a DispatchHandle passing it your IOHandle and
+ * callback functions for read, write and disconnect events.
+ *
+ * - Ensure the DispatchHandle is not deleted until the poller is no longer using it.
+ * TODO: astitcher document DispatchHandleRef to simplify this.
+ *
+ * When an event occurs on the handle, the poller calls the relevant callback and
+ * stops watching that handle. Your callback can call rewatch() or related functions
+ * to re-enable polling.
+ */
+class DispatchHandle : public PollerHandle {
+ friend class DispatchHandleRef;
+public:
+ typedef boost::function1<void, DispatchHandle&> Callback;
+ typedef std::queue<Callback> CallbackQueue;
+
+private:
+ Callback readableCallback;
+ Callback writableCallback;
+ Callback disconnectedCallback;
+ CallbackQueue interruptedCallbacks;
+ CallbackQueue callbacks; // Double buffer
+ Poller::shared_ptr poller;
+ Mutex stateLock;
+ enum {
+ IDLE,
+ STOPPING,
+ WAITING,
+ CALLING,
+ DELETING
+ } state;
+
+public:
+ /**
+ * Provide a handle to poll and a set of callbacks. Note
+ * callbacks can be 0, meaning you are not interested in that
+ * event.
+ *
+ *@param h: the handle to watch. The IOHandle encapsulates a
+ * platfrom-specific handle to an IO object (e.g. a file descriptor
+ * on Unix.)
+ *@param rCb Callback called when the handle is readable.
+ *@param wCb Callback called when the handle is writable.
+ *@param dCb Callback called when the handle is disconnected.
+ */
+ QPID_COMMON_EXTERN DispatchHandle(const IOHandle& h, Callback rCb, Callback wCb, Callback dCb);
+ QPID_COMMON_EXTERN ~DispatchHandle();
+
+ /** Add this DispatchHandle to the poller to be watched. */
+ QPID_COMMON_EXTERN void startWatch(Poller::shared_ptr poller);
+
+ /** Resume watching for all non-0 callbacks. */
+ QPID_COMMON_EXTERN void rewatch();
+ /** Resume watching for read only. */
+ QPID_COMMON_EXTERN void rewatchRead();
+
+ /** Resume watching for write only. */
+ QPID_COMMON_EXTERN void rewatchWrite();
+
+ /** Stop watching temporarily. The DispatchHandle remains
+ associated with the poller and can be re-activated using
+ rewatch. */
+ QPID_COMMON_EXTERN void unwatch();
+ /** Stop watching for read */
+ QPID_COMMON_EXTERN void unwatchRead();
+ /** Stop watching for write */
+ QPID_COMMON_EXTERN void unwatchWrite();
+
+ /** Stop watching permanently. Disassociates from the poller. */
+ QPID_COMMON_EXTERN void stopWatch();
+
+ /** Interrupt watching this handle and make a serialised callback that respects the
+ * same exclusivity guarantees as the other callbacks
+ */
+ QPID_COMMON_EXTERN void call(Callback iCb);
+
+protected:
+ QPID_COMMON_EXTERN void doDelete();
+
+private:
+ QPID_COMMON_EXTERN void processEvent(Poller::EventType dir);
+};
+
+class DispatchHandleRef {
+ DispatchHandle* ref;
+
+public:
+ typedef boost::function1<void, DispatchHandle&> Callback;
+ DispatchHandleRef(const IOHandle& h, Callback rCb, Callback wCb, Callback dCb) :
+ ref(new DispatchHandle(h, rCb, wCb, dCb))
+ {}
+
+ ~DispatchHandleRef() { ref->doDelete(); }
+
+ void startWatch(Poller::shared_ptr poller) { ref->startWatch(poller); }
+ void rewatch() { ref->rewatch(); }
+ void rewatchRead() { ref->rewatchRead(); }
+ void rewatchWrite() { ref->rewatchWrite(); }
+ void unwatch() { ref->unwatch(); }
+ void unwatchRead() { ref->unwatchRead(); }
+ void unwatchWrite() { ref->unwatchWrite(); }
+ void stopWatch() { ref->stopWatch(); }
+ void call(Callback iCb) { ref->call(iCb); }
+};
+
+}}
+
+#endif // _sys_DispatchHandle_h