--- a/CMakeLists.txt	Wed Apr 16 12:12:55 2014 +0200
+++ b/CMakeLists.txt	Tue Apr 22 13:36:51 2014 +0200
@@ -166,10 +166,12 @@
   Core/RestApi/RestApiPath.cpp
   Core/RestApi/RestApiOutput.cpp
   Core/RestApi/RestApi.cpp
+  Core/MultiThreading/ArrayFilledByThreads.cpp
   Core/MultiThreading/BagOfRunnablesBySteps.cpp
+  Core/MultiThreading/Mutex.cpp
+  Core/MultiThreading/ReaderWriterLock.cpp
   Core/MultiThreading/SharedMessageQueue.cpp
   Core/MultiThreading/ThreadedCommandProcessor.cpp
-  Core/MultiThreading/ArrayFilledByThreads.cpp
   Core/FileFormats/PngReader.cpp
   Core/FileFormats/PngWriter.cpp
   Core/SQLite/Connection.cpp

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Core/MultiThreading/ILockable.h	Tue Apr 22 13:36:51 2014 +0200
@@ -0,0 +1,50 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2014 Medical Physics Department, CHU of Liege,
+ * 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/>.
+ **/
+
+
+#pragma once
+
+#include <boost/noncopyable.hpp>
+
+namespace Orthanc
+{
+  class ILockable : public boost::noncopyable
+  {
+  public:
+    virtual ~ILockable()
+    {
+    }
+
+    virtual void Lock() = 0;
+
+    virtual void Unlock() = 0;
+  };
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Core/MultiThreading/Locker.h	Tue Apr 22 13:36:51 2014 +0200
@@ -0,0 +1,55 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2014 Medical Physics Department, CHU of Liege,
+ * 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/>.
+ **/
+
+
+#pragma once
+
+#include "ILockable.h"
+
+namespace Orthanc
+{
+  class Locker
+  {
+  private:
+    ILockable& lockable_;
+
+  public:
+    Locker(ILockable& lockable) : lockable_(lockable)
+    {
+      lockable_.Lock();
+    }
+
+    virtual ~Locker()
+    {
+      lockable_.Unlock();
+    }
+  };
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Core/MultiThreading/Mutex.cpp	Tue Apr 22 13:36:51 2014 +0200
@@ -0,0 +1,120 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2014 Medical Physics Department, CHU of Liege,
+ * 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 "Mutex.h"
+
+#include "../OrthancException.h"
+
+#if defined(_WIN32)
+#include <windows.h>
+#elif defined(__linux)
+#include <pthread.h>
+#else
+#error Support your platform here
+#endif
+
+namespace Orthanc
+{
+#if defined (_WIN32)
+
+  struct Mutex::PImpl
+  {
+    CRITICAL_SECTION criticalSection_;
+  };
+
+  Mutex::Mutex()
+  {
+    pimpl_ = new PImpl;
+    ::InitializeCriticalSection(&pimpl_->criticalSection_);
+  }
+
+  Mutex::~Mutex()
+  {
+    ::DeleteCriticalSection(&pimpl_->criticalSection_);
+    delete pimpl_;
+  }
+
+  void Mutex::Lock()
+  {
+    ::EnterCriticalSection(&pimpl_->criticalSection_);
+  }
+
+  void Mutex::Unlock()
+  {
+    ::LeaveCriticalSection(&pimpl_->criticalSection_);
+  }
+
+
+#elif defined(__linux)
+
+  struct Mutex::PImpl
+  {
+    pthread_mutex_t mutex_;
+  };
+
+  Mutex::Mutex()
+  {
+    pimpl_ = new PImpl;
+
+    if (pthread_mutex_init(&pimpl_->mutex_, NULL) != 0)
+    {
+      delete pimpl_;
+      throw OrthancException(ErrorCode_InternalError);
+    }
+  }
+
+  Mutex::~Mutex()
+  {
+    pthread_mutex_destroy(&pimpl_->mutex_);
+    delete pimpl_;
+  }
+
+  void Mutex::Lock()
+  {
+    if (pthread_mutex_lock(&pimpl_->mutex_) != 0)
+    {
+      throw OrthancException(ErrorCode_InternalError);    
+    }
+  }
+
+  void Mutex::Unlock()
+  {
+    if (pthread_mutex_unlock(&pimpl_->mutex_) != 0)
+    {
+      throw OrthancException(ErrorCode_InternalError);    
+    }
+  }
+
+#else
+#error Support your plateform here
+#endif
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Core/MultiThreading/Mutex.h	Tue Apr 22 13:36:51 2014 +0200
@@ -0,0 +1,55 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2014 Medical Physics Department, CHU of Liege,
+ * 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/>.
+ **/
+
+
+#pragma once
+
+#include "ILockable.h"
+
+namespace Orthanc
+{
+  class Mutex : public ILockable
+  {
+  private:
+    struct PImpl;
+
+    PImpl *pimpl_;
+
+  public:
+    Mutex();
+
+    ~Mutex();
+
+    virtual void Lock();
+
+    virtual void Unlock();
+  };
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Core/MultiThreading/ReaderWriterLock.cpp	Tue Apr 22 13:36:51 2014 +0200
@@ -0,0 +1,122 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2014 Medical Physics Department, CHU of Liege,
+ * 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 "ReaderWriterLock.h"
+
+#include <boost/thread/shared_mutex.hpp>
+
+namespace Orthanc
+{
+  namespace
+  {
+    // Anonymous namespace to avoid clashes between compilation
+    // modules.
+
+    class ReaderLockable : public ILockable
+    {
+    private:
+      boost::shared_mutex& lock_;
+
+    public:
+      ReaderLockable(boost::shared_mutex& lock) : lock_(lock)
+      {
+      }
+
+      virtual void Lock()
+      {
+        lock_.lock_shared();
+      }
+
+      virtual void Unlock()
+      {
+        lock_.unlock_shared();        
+      }
+    };
+
+
+    class WriterLockable : public ILockable
+    {
+    private:
+      boost::shared_mutex& lock_;
+
+    public:
+      WriterLockable(boost::shared_mutex& lock) : lock_(lock)
+      {
+      }
+
+      virtual void Lock()
+      {
+        lock_.lock();
+      }
+
+      virtual void Unlock()
+      {
+        lock_.unlock();        
+      }
+    };
+  }
+
+  struct ReaderWriterLock::PImpl
+  {
+    boost::shared_mutex lock_;
+    ReaderLockable reader_;
+    WriterLockable writer_;
+
+    PImpl() : reader_(lock_), writer_(lock_)
+    {
+    }
+  };
+
+
+  ReaderWriterLock::ReaderWriterLock()
+  {
+    pimpl_ = new PImpl;
+  }
+
+
+  ReaderWriterLock::~ReaderWriterLock()
+  {
+    delete pimpl_;
+  }
+
+
+  ILockable&  ReaderWriterLock::ForReader()
+  {
+    return pimpl_->reader_;
+  }
+
+
+  ILockable&  ReaderWriterLock::ForWriter()
+  {
+    return pimpl_->writer_;
+  }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Core/MultiThreading/ReaderWriterLock.h	Tue Apr 22 13:36:51 2014 +0200
@@ -0,0 +1,55 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2014 Medical Physics Department, CHU of Liege,
+ * 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/>.
+ **/
+
+
+#pragma once
+
+#include "ILockable.h"
+
+namespace Orthanc
+{
+  class ReaderWriterLock
+  {
+  private:
+    struct PImpl;
+
+    PImpl *pimpl_;
+
+  public:
+    ReaderWriterLock();
+
+    virtual ~ReaderWriterLock();
+
+    ILockable& ForReader();
+
+    ILockable& ForWriter();
+  };
+}

--- a/UnitTestsSources/MultiThreading.cpp	Wed Apr 16 12:12:55 2014 +0200
+++ b/UnitTestsSources/MultiThreading.cpp	Tue Apr 22 13:36:51 2014 +0200
@@ -3,6 +3,9 @@
 #include "../Core/OrthancException.h"
 #include "../Core/Toolbox.h"
 #include "../Core/MultiThreading/ArrayFilledByThreads.h"
+#include "../Core/MultiThreading/Locker.h"
+#include "../Core/MultiThreading/Mutex.h"
+#include "../Core/MultiThreading/ReaderWriterLock.h"
 #include "../Core/MultiThreading/ThreadedCommandProcessor.h"
 
 using namespace Orthanc;
@@ -185,3 +188,25 @@
       ASSERT_TRUE(s.find(i) != s.end());
   }
 }
+
+
+TEST(MultiThreading, Mutex)
+{
+  Mutex mutex;
+  Locker locker(mutex);
+}
+
+
+TEST(MultiThreading, ReaderWriterLock)
+{
+  ReaderWriterLock lock;
+
+  {
+    Locker locker1(lock.ForReader());
+    Locker locker2(lock.ForReader());
+  }
+
+  {
+    Locker locker3(lock.ForWriter());
+  }
+}

--- a/UnitTestsSources/UnitTestsMain.cpp	Wed Apr 16 12:12:55 2014 +0200
+++ b/UnitTestsSources/UnitTestsMain.cpp	Tue Apr 22 13:36:51 2014 +0200
@@ -588,7 +588,6 @@
 }
 
 
-
 int main(int argc, char **argv)
 {
   // Initialize Google's logging library.