--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Platforms/Generic/Oracle.cpp	Wed May 24 22:33:20 2017 +0200
@@ -0,0 +1,208 @@
+/**
+ * Stone of Orthanc
+ * 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 Affero General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * 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
+ * Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#include "Oracle.h"
+
+#include "../../Resources/Orthanc/Core/Logging.h"
+#include "../../Resources/Orthanc/Core/MultiThreading/SharedMessageQueue.h"
+#include "../../Resources/Orthanc/Core/OrthancException.h"
+
+#include <vector>
+
+namespace OrthancStone
+{
+  class Oracle::PImpl
+  {
+  private:
+    enum State
+    {
+      State_Init,
+      State_Started,
+      State_Stopped
+    };
+
+    boost::mutex*                  globalMutex_;
+    boost::mutex                   oracleMutex_;
+    State                          state_;
+    std::vector<boost::thread*>    threads_;
+    Orthanc::SharedMessageQueue    queue_;
+
+    static void Worker(PImpl* that)
+    {
+      for (;;)
+      {
+        State state;
+        
+        {
+          boost::mutex::scoped_lock lock(that->oracleMutex_);
+          state = that->state_;
+        }
+
+        if (state == State_Stopped)
+        {
+          break;
+        }
+
+        std::auto_ptr<Orthanc::IDynamicObject> item(that->queue_.Dequeue(100));
+        if (item.get() != NULL)
+        {
+          IOracleCommand& command = dynamic_cast<IOracleCommand&>(*item);
+          command.Execute();
+
+          if (that->globalMutex_ != NULL)
+          {
+            boost::mutex::scoped_lock lock(*that->globalMutex_);
+            command.Commit();
+          }
+          else
+          {
+            command.Commit();
+          }
+        }
+      }
+    }
+    
+  public:
+    PImpl(boost::mutex* globalMutex,
+          unsigned int threadCount) :
+      globalMutex_(globalMutex),
+      state_(State_Init),
+      threads_(threadCount)
+    {
+    }
+
+    ~PImpl()
+    {
+      if (state_ == State_Started)
+      {
+        LOG(ERROR) << "You should have manually called Oracle::Stop()";
+        Stop();
+      }
+    }
+
+    void Submit(IOracleCommand* command)
+    {
+      std::auto_ptr<IOracleCommand> protection(command);
+
+      if (command == NULL)
+      {
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_NullPointer);
+      }
+      
+      boost::mutex::scoped_lock lock(oracleMutex_);
+
+      switch (state_)
+      {
+        case State_Init:
+          LOG(ERROR) << "You must call Oracle::Start()";
+          throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
+
+        case State_Started:
+          queue_.Enqueue(protection.release());
+          break;
+
+        case State_Stopped:
+          LOG(ERROR) << "Cannot schedule a request to the Oracle after having "
+                     << "called Oracle::Stop()";
+          break;
+
+        default:
+          throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
+      }
+      
+    }
+
+    void Start()
+    {
+      boost::mutex::scoped_lock lock(oracleMutex_);
+
+      if (state_ != State_Init)
+      {
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
+      }
+      
+      for (size_t i = 0; i < threads_.size(); i++)
+      {
+        threads_[i] = new boost::thread(Worker, this);
+      }
+
+      state_ = State_Started;
+    }
+
+    void Stop()
+    {
+      {
+        boost::mutex::scoped_lock lock(oracleMutex_);
+
+        if (state_ != State_Started)
+        {
+          throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
+        }
+
+        state_ = State_Stopped;
+      }
+      
+      for (size_t i = 0; i < threads_.size(); i++)
+      {
+        if (threads_[i] != NULL)
+        {
+          if (threads_[i]->joinable())
+          {
+            threads_[i]->join();
+          }
+
+          delete threads_[i];
+        }
+      }
+    }
+  };
+  
+
+  Oracle::Oracle(boost::mutex& globalMutex,
+                 unsigned int threadCount) :
+    pimpl_(new PImpl(&globalMutex, threadCount))
+  {
+  }
+
+
+  Oracle::Oracle(unsigned int threadCount) :
+    pimpl_(new PImpl(NULL, threadCount))
+  {
+  }
+
+
+  void Oracle::Start()
+  {
+    pimpl_->Start();
+  }
+
+
+  void Oracle::Submit(IOracleCommand* command)
+  {
+    pimpl_->Submit(command);
+  }
+     
+   
+  void Oracle::Stop()
+  {
+    pimpl_->Stop();
+  }
+}