--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Core/DicomNetworking/ReusableDicomUserConnection.cpp	Tue Aug 29 21:17:35 2017 +0200
@@ -0,0 +1,188 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017 Osimis, Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * In addition, as a special exception, the copyright holders of this
+ * program give permission to link the code of its release with the
+ * OpenSSL project's "OpenSSL" library (or with modified versions of it
+ * that use the same license as the "OpenSSL" library), and distribute
+ * the linked executables. You must obey the GNU General Public License
+ * in all respects for all of the code used other than "OpenSSL". If you
+ * modify file(s) with this exception, you may extend this exception to
+ * your version of the file(s), but you are not obligated to do so. If
+ * you do not wish to do so, delete this exception statement from your
+ * version. If you delete this exception statement from all source files
+ * in the program, then also delete it here.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#include "../PrecompiledHeaders.h"
+#include "ReusableDicomUserConnection.h"
+
+#include "../Logging.h"
+#include "../OrthancException.h"
+
+namespace Orthanc
+{
+  static boost::posix_time::ptime Now()
+  {
+    return boost::posix_time::microsec_clock::local_time();
+  }
+
+  void ReusableDicomUserConnection::Open(const std::string& localAet,
+                                         const RemoteModalityParameters& remote)
+  {
+    if (connection_ != NULL &&
+        connection_->GetLocalApplicationEntityTitle() == localAet &&
+        connection_->GetRemoteApplicationEntityTitle() == remote.GetApplicationEntityTitle() &&
+        connection_->GetRemoteHost() == remote.GetHost() &&
+        connection_->GetRemotePort() == remote.GetPort() &&
+        connection_->GetRemoteManufacturer() == remote.GetManufacturer())
+    {
+      // The current connection can be reused
+      LOG(INFO) << "Reusing the previous SCU connection";
+      return;
+    }
+
+    Close();
+
+    connection_ = new DicomUserConnection();
+    connection_->SetLocalApplicationEntityTitle(localAet);
+    connection_->SetRemoteModality(remote);
+    connection_->Open();
+  }
+    
+  void ReusableDicomUserConnection::Close()
+  {
+    if (connection_ != NULL)
+    {
+      delete connection_;
+      connection_ = NULL;
+    }
+  }
+
+  void ReusableDicomUserConnection::CloseThread(ReusableDicomUserConnection* that)
+  {
+    for (;;)
+    {
+      boost::this_thread::sleep(boost::posix_time::milliseconds(100));
+      if (!that->continue_)
+      {
+        //LOG(INFO) << "Finishing the thread watching the global SCU connection";
+        return;
+      }
+
+      {
+        boost::mutex::scoped_lock lock(that->mutex_);
+        if (that->connection_ != NULL &&
+            Now() >= that->lastUse_ + that->timeBeforeClose_)
+        {
+          LOG(INFO) << "Closing the global SCU connection after timeout";
+          that->Close();
+        }
+      }
+    }
+  }
+    
+
+  ReusableDicomUserConnection::Locker::Locker(ReusableDicomUserConnection& that,
+                                              const std::string& localAet,
+                                              const RemoteModalityParameters& remote) :
+    ::Orthanc::Locker(that)
+  {
+    that.Open(localAet, remote);
+    connection_ = that.connection_;    
+  }
+
+
+  DicomUserConnection& ReusableDicomUserConnection::Locker::GetConnection()
+  {
+    if (connection_ == NULL)
+    {
+      throw OrthancException(ErrorCode_InternalError);
+    }
+
+    return *connection_;
+  }      
+
+  ReusableDicomUserConnection::ReusableDicomUserConnection() : 
+    connection_(NULL), 
+    timeBeforeClose_(boost::posix_time::seconds(5))  // By default, close connection after 5 seconds
+  {
+    lastUse_ = Now();
+    continue_ = true;
+    closeThread_ = boost::thread(CloseThread, this);
+  }
+
+  ReusableDicomUserConnection::~ReusableDicomUserConnection()
+  {
+    if (continue_)
+    {
+      LOG(ERROR) << "INTERNAL ERROR: ReusableDicomUserConnection::Finalize() should be invoked manually to avoid mess in the destruction order!";
+      Finalize();
+    }
+  }
+
+  void ReusableDicomUserConnection::SetMillisecondsBeforeClose(uint64_t ms)
+  {
+    boost::mutex::scoped_lock lock(mutex_);
+
+    if (ms == 0)
+    {
+      ms = 1;
+    }
+
+    timeBeforeClose_ = boost::posix_time::milliseconds(ms);
+  }
+
+  void ReusableDicomUserConnection::Lock()
+  {
+    mutex_.lock();
+  }
+
+  void ReusableDicomUserConnection::Unlock()
+  {
+    if (connection_ != NULL &&
+        connection_->GetRemoteManufacturer() == ModalityManufacturer_StoreScp)
+    {
+      // "storescp" from DCMTK has problems when reusing a
+      // connection. Always close.
+      Close();
+    }
+
+    lastUse_ = Now();
+    mutex_.unlock();
+  }
+
+  
+  void ReusableDicomUserConnection::Finalize()
+  {
+    if (continue_)
+    {
+      continue_ = false;
+
+      if (closeThread_.joinable())
+      {
+        closeThread_.join();
+      }
+
+      Close();
+    }
+  }
+}
+