Viewing file:  callback_queue.h (1.96 KB) -rw-r--r--
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#ifndef SRC_CALLBACK_QUEUE_H_
#define SRC_CALLBACK_QUEUE_H_
#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
#include <atomic>
namespace node {
namespace CallbackFlags {
enum Flags {
kUnrefed = 0,
kRefed = 1,
};
}
// A queue of C++ functions that take Args... as arguments and return R
// (this is similar to the signature of std::function).
// New entries are added using `CreateCallback()`/`Push()`, and removed using
// `Shift()`.
// The `refed` flag is left for easier use in situations in which some of these
// should be run even if nothing else is keeping the event loop alive.
template <typename R, typename... Args>
class CallbackQueue {
public:
class Callback {
public:
explicit inline Callback(CallbackFlags::Flags flags);
virtual ~Callback() = default;
virtual R Call(Args... args) = 0;
inline CallbackFlags::Flags flags() const;
private:
inline std::unique_ptr<Callback> get_next();
inline void set_next(std::unique_ptr<Callback> next);
CallbackFlags::Flags flags_;
std::unique_ptr<Callback> next_;
friend class CallbackQueue;
};
template <typename Fn>
inline std::unique_ptr<Callback> CreateCallback(
Fn&& fn, CallbackFlags::Flags);
inline std::unique_ptr<Callback> Shift();
inline void Push(std::unique_ptr<Callback> cb);
// ConcatMove adds elements from 'other' to the end of this list, and clears
// 'other' afterwards.
inline void ConcatMove(CallbackQueue&& other);
// size() is atomic and may be called from any thread.
inline size_t size() const;
private:
template <typename Fn>
class CallbackImpl final : public Callback {
public:
CallbackImpl(Fn&& callback, CallbackFlags::Flags flags);
R Call(Args... args) override;
private:
Fn callback_;
};
std::atomic<size_t> size_ {0};
std::unique_ptr<Callback> head_;
Callback* tail_ = nullptr;
};
} // namespace node
#endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
#endif // SRC_CALLBACK_QUEUE_H_
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