Optimization step 'generate_features': Added simple threadsafe queue.

base/queue.hpp

@@ -0,0 +1,90 @@
+#pragma once
+
+#include <condition_variable>
+#include <mutex>
+#include <queue>
+
+namespace base
+{
+namespace threads
+{
+template <typename T>
+class DataWrapper
+{
+public:
+  DataWrapper() : m_is_empty(true) {}
+  DataWrapper(T const & data) : m_data(data), m_is_empty(false) {}
+  DataWrapper(T && data) : m_data(std::move(data)), m_is_empty(false) {}
+
+  T const & Get() const { return m_data; }
+  T & Get() { return m_data; }
+
+  bool IsEmpty() const { return m_is_empty; }
+
+private:
+  bool m_is_empty;
+  T m_data;
+};
+
+template <typename T>
+class Queue
+{
+public:
+  Queue() = default;
+  Queue(Queue const & other)
+  {
+    std::lock_guard<std::mutex> lk(other.m_mutex);
+    m_queue = other.m_queue;
+  }
+
+  void Push(T const & value)
+  {
+    {
+      std::lock_guard<std::mutex> lk(m_mutex);
+      m_queue.push(value);
+    }
+    m_cond.notify_one();
+  }
+
+  void Push(T && value)
+  {
+    {
+      std::lock_guard<std::mutex> lk(m_mutex);
+      m_queue.push(std::move(value));
+    }
+    m_cond.notify_one();
+  }
+
+  void WaitAndPop(T & value)
+  {
+    std::unique_lock<std::mutex> lk(m_mutex);
+    m_cond.wait(lk, [this]{ return !m_queue.empty(); });
+    value = m_queue.front();
+    m_queue.pop();
+  }
+
+  bool TryPop(T & value)
+  {
+    std::lock_guard<std::mutex> lk(m_mutex);
+    if (m_queue.empty())
+      return false;
+
+    value = m_queue.front();
+    m_queue.pop();
+    return true;
+
+  }
+
+  bool Empty() const
+  {
+    std::lock_guard<std::mutex> lk(m_mutex);
+    return m_queue.empty();
+  }
+
+private:
+  mutable std::mutex m_mutex;
+  std::queue<T> m_queue;
+  std::condition_variable m_cond;
+};
+}  // namespace threads
+}  // namespace base