| // |
| // detail/op_queue.hpp |
| // ~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| // |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| // |
| |
| #ifndef ASIO_DETAIL_OP_QUEUE_HPP |
| #define ASIO_DETAIL_OP_QUEUE_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include "asio/detail/noncopyable.hpp" |
| |
| #include "asio/detail/push_options.hpp" |
| |
| namespace asio { |
| namespace detail { |
| |
| template <typename Operation> |
| class op_queue; |
| |
| class op_queue_access |
| { |
| public: |
| template <typename Operation> |
| static Operation* next(Operation* o) |
| { |
| return static_cast<Operation*>(o->next_); |
| } |
| |
| template <typename Operation1, typename Operation2> |
| static void next(Operation1*& o1, Operation2* o2) |
| { |
| o1->next_ = o2; |
| } |
| |
| template <typename Operation> |
| static void destroy(Operation* o) |
| { |
| o->destroy(); |
| } |
| |
| template <typename Operation> |
| static Operation*& front(op_queue<Operation>& q) |
| { |
| return q.front_; |
| } |
| |
| template <typename Operation> |
| static Operation*& back(op_queue<Operation>& q) |
| { |
| return q.back_; |
| } |
| }; |
| |
| template <typename Operation> |
| class op_queue |
| : private noncopyable |
| { |
| public: |
| // Constructor. |
| op_queue() |
| : front_(0), |
| back_(0) |
| { |
| } |
| |
| // Destructor destroys all operations. |
| ~op_queue() |
| { |
| while (Operation* op = front_) |
| { |
| pop(); |
| op_queue_access::destroy(op); |
| } |
| } |
| |
| // Get the operation at the front of the queue. |
| Operation* front() |
| { |
| return front_; |
| } |
| |
| // Pop an operation from the front of the queue. |
| void pop() |
| { |
| if (front_) |
| { |
| Operation* tmp = front_; |
| front_ = op_queue_access::next(front_); |
| if (front_ == 0) |
| back_ = 0; |
| op_queue_access::next(tmp, static_cast<Operation*>(0)); |
| } |
| } |
| |
| // Push an operation on to the back of the queue. |
| void push(Operation* h) |
| { |
| op_queue_access::next(h, static_cast<Operation*>(0)); |
| if (back_) |
| { |
| op_queue_access::next(back_, h); |
| back_ = h; |
| } |
| else |
| { |
| front_ = back_ = h; |
| } |
| } |
| |
| // Push all operations from another queue on to the back of the queue. The |
| // source queue may contain operations of a derived type. |
| template <typename OtherOperation> |
| void push(op_queue<OtherOperation>& q) |
| { |
| if (Operation* other_front = op_queue_access::front(q)) |
| { |
| if (back_) |
| op_queue_access::next(back_, other_front); |
| else |
| front_ = other_front; |
| back_ = op_queue_access::back(q); |
| op_queue_access::front(q) = 0; |
| op_queue_access::back(q) = 0; |
| } |
| } |
| |
| // Whether the queue is empty. |
| bool empty() const |
| { |
| return front_ == 0; |
| } |
| |
| private: |
| friend class op_queue_access; |
| |
| // The front of the queue. |
| Operation* front_; |
| |
| // The back of the queue. |
| Operation* back_; |
| }; |
| |
| } // namespace detail |
| } // namespace asio |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #endif // ASIO_DETAIL_OP_QUEUE_HPP |