From 69bbae0072638a88b3d2d722167fba24713e165f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Bylica?= <chfast@gmail.com>
Date: Wed, 22 Jul 2015 17:03:22 +0200
Subject: [PATCH] concurrent_queue

---
 libdevcore/concurrent_queue.h | 60 +++++++++++++++++++++++++++++++++++
 libevm/SmartVM.cpp            | 34 +-------------------
 2 files changed, 61 insertions(+), 33 deletions(-)
 create mode 100644 libdevcore/concurrent_queue.h

diff --git a/libdevcore/concurrent_queue.h b/libdevcore/concurrent_queue.h
new file mode 100644
index 000000000..2e88fc576
--- /dev/null
+++ b/libdevcore/concurrent_queue.h
@@ -0,0 +1,60 @@
+/*
+	This file is part of cpp-ethereum.
+
+	cpp-ethereum 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.
+
+	cpp-ethereum 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 cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#pragma once
+#include <utility>
+#include <queue>
+#include <condition_variable>
+#include <mutex>
+
+
+namespace dev
+{
+
+/// Concurrent queue.
+/// You can push and pop elements to/from the queue. Pop will block until the queue is not empty.
+/// The default backend (_QueueT) is std::queue. It can be changed to any type that has
+/// proper push(), pop(), empty() and front() methods.
+template<typename _T, typename _QueueT = std::queue<_T>>
+class concurrent_queue
+{
+public:
+	template<typename _U>
+	void push(_U&& _elem)
+	{
+		{
+			std::lock_guard<decltype(x_mutex)> guard{x_mutex};
+			m_queue.push(std::forward<_U>(_elem));
+		}
+		m_cv.notify_one();
+	}
+
+	_T pop()
+	{
+		std::unique_lock<std::mutex> lock{x_mutex};
+		m_cv.wait(lock, [this]{ return !m_queue.empty(); });
+		auto item = std::move(m_queue.front());
+		m_queue.pop();
+		return item;
+	}
+
+private:
+	_QueueT m_queue;
+	std::mutex x_mutex;
+	std::condition_variable m_cv;
+};
+
+}
diff --git a/libevm/SmartVM.cpp b/libevm/SmartVM.cpp
index 2246e0455..5d814eff0 100644
--- a/libevm/SmartVM.cpp
+++ b/libevm/SmartVM.cpp
@@ -21,9 +21,7 @@
 #include "SmartVM.h"
 #include <unordered_map>
 #include <thread>
-#include <mutex>
-#include <condition_variable>
-#include <queue>
+#include <libdevcore/concurrent_queue.h>
 #include <libdevcore/Log.h>
 #include <libdevcore/SHA3.h>
 #include <libdevcore/Guards.h>
@@ -33,36 +31,6 @@
 
 namespace dev
 {
-
-template<typename _T, typename _QueueT = std::queue<_T>>
-class concurrent_queue
-{
-public:
-	template<typename _U>
-	void push(_U&& _elem)
-	{
-		{
-			std::lock_guard<decltype(x_mutex)> guard{x_mutex};
-			m_queue.push(std::forward<_U>(_elem));
-		}
-		m_cv.notify_one();
-	}
-
-	_T pop()
-	{
-		std::unique_lock<std::mutex> lock{x_mutex};
-		m_cv.wait(lock, [this]{ return !m_queue.empty(); });
-		auto item = std::move(m_queue.front());
-		m_queue.pop();
-		return item;
-	}
-
-private:
-	_QueueT m_queue;
-	std::mutex x_mutex;
-	std::condition_variable m_cv;
-};
-
 namespace eth
 {
 namespace