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#ifndef MBGL_UTIL_RUN_LOOP
#define MBGL_UTIL_RUN_LOOP
#include <mbgl/util/noncopyable.hpp>
#include <mbgl/util/std.hpp>
#include <mbgl/util/uv_detail.hpp>
#include <functional>
#include <utility>
#include <queue>
#include <mutex>
namespace mbgl {
namespace util {
class RunLoop : private util::noncopyable {
public:
RunLoop(uv_loop_t*);
~RunLoop();
void stop();
// Invoke fn(args...) on this RunLoop.
template <class Fn, class... Args>
void invoke(Fn&& fn, Args&&... args) {
auto tuple = std::make_tuple(std::move(args)...);
auto invokable = util::make_unique<Invoker<Fn, decltype(tuple), Args...>>(std::move(fn), std::move(tuple));
withMutex([&] { queue.push(std::move(invokable)); });
async.send();
}
// Return a function that invokes the given function on this RunLoop.
template <class... Args>
auto bind(std::function<void (Args...)> fn) {
return [this, fn = std::move(fn)] (Args&&... args) {
invoke(std::move(fn), std::move(args)...);
};
}
// Invoke fn(args...) on this RunLoop, then invoke callback(result) on the current RunLoop.
template <class R, class Fn, class... Args>
void invokeWithResult(Fn&& fn, std::function<void (R)> callback, Args&&... args) {
invoke([fn = std::move(fn), callback = current.get()->bind(callback)] (Args&&... a) mutable {
callback(fn(std::forward<Args>(a)...));
}, std::forward<Args>(args)...);
}
// Invoke fn(args...) on this RunLoop, then invoke callback() on the current RunLoop.
template <class Fn, class... Args>
void invokeWithResult(Fn&& fn, std::function<void ()> callback, Args&&... args) {
invoke([fn = std::move(fn), callback = current.get()->bind(callback)] (Args&&... a) mutable {
fn(std::forward<Args>(a)...);
callback();
}, std::forward<Args>(args)...);
}
uv_loop_t* get() { return async.get()->loop; }
static uv::tls<RunLoop> current;
private:
// A movable type-erasing invokable entity wrapper. This allows to store arbitrary invokable
// things (like std::function<>, or the result of a movable-only std::bind()) in the queue.
// Source: http://stackoverflow.com/a/29642072/331379
struct Message {
virtual void operator()() = 0;
virtual ~Message() = default;
};
template <class F, class P, class... Args>
struct Invoker : Message {
Invoker(F&& f, P&& p)
: func(std::move(f)),
params(std::move(p)) {
}
void operator()() override {
invoke(std::index_sequence_for<Args...>{});
}
template <std::size_t... I>
void invoke(std::index_sequence<I...>) {
func(std::forward<Args>(std::get<I>(params))...);
}
F func;
P params;
};
using Queue = std::queue<std::unique_ptr<Message>>;
void withMutex(std::function<void()>&&);
void process();
Queue queue;
std::mutex mutex;
uv::async async;
};
}
}
#endif
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