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#ifndef MBGL_UTIL_RUN_LOOP
#define MBGL_UTIL_RUN_LOOP
#include <mbgl/util/noncopyable.hpp>
#include <mbgl/util/work_task.hpp>
#include <mbgl/util/work_request.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();
static RunLoop* Get() {
return current.get();
}
static uv_loop_t* getLoop() {
return current.get()->get();
}
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 task = std::make_shared<Invoker<Fn, decltype(tuple)>>(
std::move(fn),
std::move(tuple));
withMutex([&] { queue.push(task); });
async.send();
}
// Post the cancellable work fn(args...) to this RunLoop.
template <class Fn, class... Args>
std::unique_ptr<WorkRequest>
invokeCancellable(Fn&& fn, Args&&... args) {
auto flag = std::make_shared<bool>();
*flag = false;
auto tuple = std::make_tuple(std::move(args)...);
auto task = std::make_shared<Invoker<Fn, decltype(tuple)>>(
std::move(fn),
std::move(tuple),
flag);
withMutex([&] { queue.push(task); });
async.send();
return std::make_unique<WorkRequest>(task);
}
// Invoke fn(args...) on this RunLoop, then invoke callback(results...) on the current RunLoop.
template <class Fn, class Cb, class... Args>
std::unique_ptr<WorkRequest>
invokeWithCallback(Fn&& fn, Cb&& callback, Args&&... args) {
auto flag = std::make_shared<bool>();
*flag = false;
auto after = RunLoop::current.get()->bind([flag, callback] (auto&&... results) {
if (!*flag) {
callback(std::move(results)...);
}
});
auto tuple = std::make_tuple(std::move(args)..., after);
auto task = std::make_shared<Invoker<Fn, decltype(tuple)>>(
std::move(fn),
std::move(tuple),
flag);
withMutex([&] { queue.push(task); });
async.send();
return std::make_unique<WorkRequest>(task);
}
// Return a function that invokes the given function on this RunLoop.
template <class Fn>
auto bind(Fn&& fn) {
return [this, fn = std::move(fn)] (auto&&... args) {
// `this->` is a workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61636
this->invoke(std::move(fn), std::move(args)...);
};
}
uv_loop_t* get() { return async.get()->loop; }
private:
template <class F, class P>
class Invoker : public WorkTask {
public:
Invoker(F&& f, P&& p, std::shared_ptr<bool> canceled_ = nullptr)
: canceled(canceled_),
func(std::move(f)),
params(std::move(p)) {
}
void operator()() override {
// Lock the mutex while processing so that cancel() will block.
std::lock_guard<std::recursive_mutex> lock(mutex);
if (!canceled || !*canceled) {
invoke(std::make_index_sequence<std::tuple_size<P>::value>{});
}
}
// If the task has not yet begun, this will cancel it.
// If the task is in progress, this will block until it completed. (Currently
// necessary because of shared state, but should be removed.) It will also
// cancel the after callback.
// If the task has completed, but the after callback has not executed, this
// will cancel the after callback.
// If the task has completed and the after callback has executed, this will
// do nothing.
void cancel() override {
std::lock_guard<std::recursive_mutex> lock(mutex);
*canceled = true;
}
private:
template <std::size_t... I>
void invoke(std::index_sequence<I...>) {
func(std::get<I>(std::forward<P>(params))...);
}
std::recursive_mutex mutex;
std::shared_ptr<bool> canceled;
F func;
P params;
};
using Queue = std::queue<std::shared_ptr<WorkTask>>;
void withMutex(std::function<void()>&&);
void process();
Queue queue;
std::recursive_mutex mutex;
uv::async async;
static uv::tls<RunLoop> current;
};
}
}
#endif
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