Added a thread secure blocking queue

src/servers/Server_Common/Util/LockedWaitQueue.h

@@ -0,0 +1,98 @@
+#ifndef _LOCKED_WAIT_H
+#define _LOCKED_WAIT_H
+
+#include <condition_variable>
+#include <mutex>
+#include <queue>
+#include <atomic>
+#include <type_traits>
+
+namespace Core 
+{
+
+template< typename T >
+class LockedWaitQueue
+{
+private:
+    std::mutex m_queueLock;
+    std::queue< T > m_queue;
+    std::condition_variable m_condition;
+    std::atomic<bool> m_shutdown;
+
+public:
+
+    LockedWaitQueue<T>() : m_shutdown(false) { }
+
+    void push( const T& value )
+    {
+        std::lock_guard< std::mutex > lock( m_queueLock );
+        m_queue.push( std::move( value ) );
+
+        m_condition.notify_one();
+    }
+
+    bool empty()
+    {
+        std::lock_guard< std::mutex > lock( m_queueLock );
+
+        return _queue.empty();
+    }
+
+    bool pop( T& value )
+    {
+        std::lock_guard< std::mutex > lock( m_queueLock );
+
+        if( m_queue.empty() || m_shutdown )
+            return false;
+
+        value = m_queue.front();
+
+        m_queue.pop();
+
+        return true;
+    }
+
+    void waitAndPop( T& value )
+    {
+        std::unique_lock< std::mutex > lock( m_queueLock );
+
+        while( m_queue.empty() && !m_shutdown )
+            m_condition.wait(lock);
+
+        if( m_queue.empty() || m_shutdown )
+            return;
+
+        value = m_queue.front();
+
+        m_queue.pop();
+    }
+
+    void cancel()
+    {
+        std::unique_lock< std::mutex > lock( m_queueLock );
+
+        while( !m_queue.empty() )
+        {
+            T& value = m_queue.front();
+
+            deleteQueuedObject( value );
+
+            m_queue.pop();
+        }
+
+        _shutdown = true;
+
+        _condition.notify_all();
+    }
+
+private:
+    template< typename E = T >
+    typename std::enable_if<std::is_pointer<E>::value>::type deleteQueuedObject( E& obj ) { delete obj; }
+
+    template< typename E = T >
+    typename std::enable_if<!std::is_pointer<E>::value>::type deleteQueuedObject( E const& ) { }
+};
+}
+
+#endif
+