FairMQ: Introduce callbacks for the FairMQUnmanagedRegion.

Callbacks are called when the data buffer of the message assiciated
with the corresponding region is no longer needed by the transport.
Example in examples/advanced/Region/

fairmq/shmem/Manager.h

@@ -0,0 +1,81 @@
+/********************************************************************************
+ *    Copyright (C) 2014 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
+ *                                                                              *
+ *              This software is distributed under the terms of the             *
+ *         GNU Lesser General Public Licence version 3 (LGPL) version 3,        *
+ *                  copied verbatim in the file "LICENSE"                       *
+ ********************************************************************************/
+/**
+ * FairMQShmManager.h
+ *
+ * @since 2016-04-08
+ * @author A. Rybalchenko
+ */
+
+#ifndef FAIR_MQ_SHMEM_MANAGER_H_
+#define FAIR_MQ_SHMEM_MANAGER_H_
+
+#include "FairMQLogger.h"
+#include "FairMQMessage.h"
+#include "fairmq/Tools.h"
+#include "Region.h"
+#include "Common.h"
+
+#include <boost/interprocess/managed_shared_memory.hpp>
+#include <boost/interprocess/ipc/message_queue.hpp>
+
+#include <thread>
+#include <queue>
+#include <string>
+#include <vector>
+#include <functional>
+#include <unordered_map>
+#include <mutex>
+#include <condition_variable>
+
+namespace fair
+{
+namespace mq
+{
+namespace shmem
+{
+
+class Manager
+{
+    friend class Region;
+
+  public:
+    Manager(const std::string& name, size_t size);
+
+    Manager() = delete;
+
+    Manager(const Manager&) = delete;
+    Manager operator=(const Manager&) = delete;
+
+    boost::interprocess::managed_shared_memory& Segment();
+
+    void Interrupt();
+    void Resume();
+
+    boost::interprocess::mapped_region* CreateRegion(const size_t size, const uint64_t id, FairMQRegionCallback callback);
+    boost::interprocess::mapped_region* GetRemoteRegion(const uint64_t id);
+    void RemoveRegion(const uint64_t id);
+
+    boost::interprocess::message_queue* GetRegionQueue(const uint64_t id);
+
+    void RemoveSegment();
+
+    boost::interprocess::managed_shared_memory& ManagementSegment();
+
+  private:
+    std::string fName;
+    boost::interprocess::managed_shared_memory fSegment;
+    boost::interprocess::managed_shared_memory fManagementSegment;
+    std::unordered_map<uint64_t, Region> fRegions;
+};
+
+} // namespace shmem
+} // namespace mq
+} // namespace fair
+
+#endif /* FAIR_MQ_SHMEM_MANAGER_H_ */