Squashed 'libs/CommService/' content from commit 7ccc0fc

git-subtree-dir: libs/CommService
git-subtree-split: 7ccc0fce88bbc5969df060058cf0fb57abe3bcf9

libs/libbattle-com/include/BC/BasicMessageQueue.hpp

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+#pragma once
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at https://mozilla.org/MPL/2.0/.
+*/
+
+/**
+* @file
+* @copyright MPLv2
+*/
+#include <mutex>
+#include <queue>
+#include <memory>
+#include <condition_variable>
+#include <BC/Message.hpp>
+
+namespace BC{
+  /**
+    * @class BasicMessageQueue
+    *
+    * This class encapsulates shared storage which is a queue and protect it
+    * with a mutex. In Addition there is a condition variable to notify other
+    * threads if there is new data in the queue.
+    */
+  class BasicMessageQueue
+  {
+  private:
+    std::queue<std::unique_ptr<BC::Message>> q;
+    std::mutex mx;
+    std::condition_variable condVar;
+  public:
+    /**
+      * @brief default constructor for class BasicMessageQueue
+      */
+    BasicMessageQueue();
+
+    /**
+      * @brief appends given message to queue
+      *
+      * The storage is protected by a mutex. Makes a notify_one call to inform 
+      * in waiting thread that there is a new message in the queue.
+      *
+      * @param msg - incoming message
+      */
+    void appendMessage( std::unique_ptr<BC::Message> msg );
+
+    /**
+      * @brief gets the fron message from the queue
+      *
+      * This method gets the front message in the queue and deletes it from the 
+      * queue. The storage is protected by a mutex. If the queue is empty the
+      * function throws an exception.
+      *
+      * @result msg - returns the front message from the queue
+      * @throws length_error - if queue is empty this method throws length_error exception
+      */
+    std::unique_ptr<BC::Message> getMessage();
+
+    /**
+      * @brief waits for new message to be added
+      *
+      * If the queue is empty this method waits for a notfication on the condition variable.
+      * It returns the front message and deletes it from the queue. This action is protected 
+      * by a mutex.
+      *
+      * @result msg - returns the first/front message in the queue
+      * @throws length_error - if queue is empty this method throws length_error exception
+      */
+    std::unique_ptr<BC::Message> waitForNewMessage();
+
+    /**
+      * @brief method size
+      *
+      * @result size - current size of the message queue
+      */
+    unsigned int size();
+
+  }; //BasicMessageQueue
+
+}; // namespace BC