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/Region.cxx

@@ -0,0 +1,121 @@
+/********************************************************************************
+ *    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"                       *
+ ********************************************************************************/
+
+#include "Region.h"
+#include "Common.h"
+#include "Manager.h"
+
+#include <boost/thread/thread_time.hpp>
+
+#include <chrono>
+
+namespace fair
+{
+namespace mq
+{
+namespace shmem
+{
+
+using namespace std;
+
+namespace bipc = boost::interprocess;
+namespace bpt = boost::posix_time;
+
+Region::Region(Manager& manager, uint64_t id, uint64_t size, bool remote, FairMQRegionCallback callback)
+    : fManager(manager)
+    , fRemote(remote)
+    , fStop(false)
+    , fName("fmq_shm_region_" + to_string(id))
+    , fQueueName("fmq_shm_region_queue_" + to_string(id))
+    , fShmemObject()
+    , fQueue(nullptr)
+    , fWorker()
+    , fCallback(callback)
+{
+    if (fRemote)
+    {
+        fShmemObject = bipc::shared_memory_object(bipc::open_only, fName.c_str(), bipc::read_write);
+        LOG(DEBUG) << "shmem: located remote region: " << fName;
+
+        fQueue = fair::mq::tools::make_unique<bipc::message_queue>(bipc::open_only, fQueueName.c_str());
+        LOG(DEBUG) << "shmem: located remote region queue: " << fQueueName;
+    }
+    else
+    {
+        fShmemObject = bipc::shared_memory_object(bipc::create_only, fName.c_str(), bipc::read_write);
+        LOG(DEBUG) << "shmem: created region: " << fName;
+        fShmemObject.truncate(size);
+
+        fQueue = fair::mq::tools::make_unique<bipc::message_queue>(bipc::create_only, fQueueName.c_str(), 10000, sizeof(RegionBlock));
+        LOG(DEBUG) << "shmem: created region queue: " << fQueueName;
+    }
+    fRegion = bipc::mapped_region(fShmemObject, bipc::read_write); // TODO: add HUGEPAGES flag here
+    // fRegion = bipc::mapped_region(fShmemObject, bipc::read_write, 0, 0, 0, MAP_HUGETLB | MAP_HUGE_1GB);
+}
+
+void Region::StartReceivingAcks()
+{
+    fWorker = std::thread(&Region::ReceiveAcks, this);
+}
+
+void Region::ReceiveAcks()
+{
+    unsigned int priority;
+    bipc::message_queue::size_type recvdSize;
+
+    while (!fStop) // end thread condition (should exist until region is destroyed)
+    {
+        auto rcvTill = bpt::microsec_clock::universal_time() + bpt::milliseconds(200);
+        RegionBlock block;
+        if (fQueue->timed_receive(&block, sizeof(RegionBlock), recvdSize, priority, rcvTill))
+        {
+            // LOG(DEBUG) << "received: " << block.fHandle << " " << block.fSize << " " << block.fMessageId;
+            if (fCallback)
+            {
+                fCallback(reinterpret_cast<char*>(fRegion.get_address()) + block.fHandle, block.fSize);
+            }
+        }
+        else
+        {
+            // LOG(DEBUG) << "queue " << fQueueName << " timeout!";
+        }
+    } // while !fStop
+
+    LOG(DEBUG) << "worker for " << fName << " leaving.";
+}
+
+Region::~Region()
+{
+    if (!fRemote)
+    {
+        fStop = true;
+        if (fWorker.joinable())
+        {
+            fWorker.join();
+        }
+
+        if (bipc::shared_memory_object::remove(fName.c_str()))
+        {
+            LOG(DEBUG) << "shmem: destroyed region " << fName;
+        }
+
+        if (bipc::message_queue::remove(fQueueName.c_str()))
+        {
+            LOG(DEBUG) << "shmem: removed region queue " << fName;
+        }
+    }
+    else
+    {
+        // LOG(DEBUG) << "shmem: region '" << fName << "' is remote, no cleanup necessary.";
+        LOG(DEBUG) << "shmem: region queue '" << fQueueName << "' is remote, no cleanup necessary";
+    }
+}
+
+} // namespace shmem
+} // namespace mq
+} // namespace fair