repo_stack.h

#pragma once

#include <stack>

#include <boost/thread.hpp>
#include <boost/date_time.hpp>

namespace repo{
    namespace lib{
        template <class T>
        class RepoStack
        {
        public:
            RepoStack(){}
            ~RepoStack(){}

            void push(const T& item) {
                boost::mutex::scoped_lock lock(pushMutex);
                stack.push_back(item);
            }
            T pop() {
                //order potentially matters. Think before shuffling!
                boost::mutex::scoped_lock popLock(popMutex); //stopping anyone from popping
                boost::mutex::scoped_lock pushLock(pushMutex); //stopping anyone from pushing

                while (stack.empty())
                {
                    //stack is empty. Release the push lock and try again in 50ms
                    pushLock.unlock();
                    boost::this_thread::sleep(boost::posix_time::milliseconds(50));
                    pushLock.lock();
                }

                T item = (T)stack.back();
                stack.pop_back();
                return item;
            }

            std::vector<T> empty()
            {
                boost::mutex::scoped_lock popLock(popMutex); //stopping anyone from popping
                boost::mutex::scoped_lock pushLock(pushMutex); //stopping anyone from pushing
                std::vector<T> clone = stack;
                stack.clear();
                return clone;
            }

        private:
            std::vector<T> stack;
            mutable boost::mutex pushMutex;
            mutable boost::mutex popMutex;
        };
    }
}