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

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

include/CommService/ThreadsafeQueue.hpp

@@ -0,0 +1,47 @@
+#include <optional>
+#include <queue>
+#include <mutex>
+
+template<typename T>
+class ThreadsafeQueue {
+  std::queue<T> queue_;
+  mutable std::mutex mutex_;
+ 
+  // Moved out of public interface to prevent races between this
+  // and pop().
+  bool empty() const {
+    return queue_.empty();
+  }
+ 
+ public:
+  ThreadsafeQueue() = default;
+  ThreadsafeQueue(const ThreadsafeQueue<T> &) = delete ;
+  ThreadsafeQueue& operator=(const ThreadsafeQueue<T> &) = delete ;
+ 
+  ThreadsafeQueue(ThreadsafeQueue<T>&& other) {
+    std::lock_guard<std::mutex> lock(mutex_);
+    queue_ = std::move(other.queue_);
+  }
+ 
+  virtual ~ThreadsafeQueue() { }
+ 
+  unsigned long size() const {
+    std::lock_guard<std::mutex> lock(mutex_);
+    return queue_.size();
+  }
+ 
+  std::optional<T> pop() {
+    std::lock_guard<std::mutex> lock(mutex_);
+    if (queue_.empty()) {
+      return {};
+    }
+    T tmp = queue_.front();
+    queue_.pop();
+    return tmp;
+  }
+ 
+  void push(const T &item) {
+    std::lock_guard<std::mutex> lock(mutex_);
+    queue_.push(item);
+  }
+};