-#pragma once\r
-\r
-#include "enum_class.h"\r
-\r
-#include <boost/thread/future.hpp>\r
-#include <boost/thread/thread.hpp>\r
-#include <boost/shared_ptr.hpp>\r
-\r
-#include <functional>\r
-\r
-namespace caspar {\r
- \r
-struct launch_policy_def\r
-{\r
- enum type\r
- {\r
- async = 1,\r
- deferred = 2\r
- };\r
-};\r
-typedef caspar::enum_class<launch_policy_def> launch;\r
-\r
-namespace detail {\r
-\r
-template<typename R, typename F>\r
-struct callback_object: public boost::detail::future_object<R>\r
-{ \r
- F f;\r
- bool done;\r
-\r
- template<typename F2>\r
- callback_object(F2&& f)\r
- : f(std::forward<F2>(f))\r
- , done(false)\r
- {\r
- }\r
- \r
- void operator()()\r
- { \r
- boost::lock_guard<boost::mutex> lock2(mutex);\r
-\r
- if(done)\r
- return;\r
-\r
- try\r
- {\r
- this->mark_finished_with_result_internal(f());\r
- }\r
- catch(...)\r
- {\r
- this->mark_exceptional_finish_internal(boost::current_exception());\r
- }\r
-\r
- done = true;\r
- }\r
-};\r
-\r
-template<typename F>\r
-struct callback_object<void, F> : public boost::detail::future_object<void>\r
-{ \r
- F f;\r
- bool done;\r
-\r
- template<typename F2>\r
- callback_object(F2&& f)\r
- : f(std::forward<F2>(f))\r
- , done(false)\r
- {\r
- }\r
-\r
- void operator()()\r
- {\r
- boost::lock_guard<boost::mutex> lock2(mutex);\r
- \r
- if(done)\r
- return;\r
-\r
- try\r
- {\r
- f();\r
- this->mark_finished_with_result_internal();\r
- }\r
- catch(...)\r
- {\r
- this->mark_exceptional_finish_internal(boost::current_exception());\r
- }\r
-\r
- done = true;\r
- }\r
-};\r
-\r
-}\r
- \r
-template<typename F>\r
-auto async(launch policy, F&& f) -> boost::unique_future<decltype(f())>\r
-{ \r
- typedef decltype(f()) result_type;\r
- \r
- if((policy & launch::async) != 0)\r
- {\r
- typedef boost::packaged_task<result_type> task_t;\r
-\r
- auto task = task_t(std::forward<F>(f)); \r
- auto future = task.get_future();\r
- \r
- boost::thread(std::move(task)).detach();\r
- \r
- return std::move(future);\r
- }\r
- else if((policy & launch::deferred) != 0)\r
- { \r
- // HACK: THIS IS A MAYOR HACK!\r
-\r
- typedef boost::detail::future_object<result_type> future_object_t;\r
- \r
- auto callback_object = boost::make_shared<detail::callback_object<result_type, F>>(std::forward<F>(f));\r
- auto callback_object_raw = callback_object.get();\r
- auto future_object = boost::static_pointer_cast<future_object_t>(std::move(callback_object));\r
-\r
- future_object->set_wait_callback(std::mem_fn(&detail::callback_object<result_type, F>::operator()), callback_object_raw);\r
- \r
- boost::unique_future<result_type> future;\r
-\r
- static_assert(sizeof(future) == sizeof(future_object), "");\r
-\r
- reinterpret_cast<boost::shared_ptr<future_object_t>&>(future) = std::move(future_object); // Get around the "private" encapsulation.\r
- return std::move(future);\r
- }\r
- else\r
- throw std::invalid_argument("policy");\r
-}\r
- \r
-template<typename F>\r
-auto async(F&& f) -> boost::unique_future<decltype(f())>\r
-{ \r
- return async(launch::async | launch::deferred, std::forward<F>(f));\r
-}\r
-\r
-template<typename T>\r
-auto make_shared(boost::unique_future<T>&& f) -> boost::shared_future<T>\r
-{ \r
- return boost::shared_future<T>(std::move(f));\r
-}\r
-\r
-template<typename T>\r
-auto flatten(boost::unique_future<T>&& f) -> boost::unique_future<decltype(f.get().get())>\r
-{\r
- auto shared_f = make_shared(std::move(f));\r
- return async(launch::deferred, [=]() mutable\r
- {\r
- return shared_f.get().get();\r
- });\r
-}\r
-\r
+#pragma once
+
+#include <boost/thread/mutex.hpp>
+#include <boost/function.hpp>
+#include <boost/optional.hpp>
+
+#include <functional>
+#include <future>
+
+namespace caspar {
+
+template<typename T>
+auto flatten(std::future<T>&& f) -> std::future<typename std::decay<decltype(f.get().get())>::type>
+{
+ auto shared_f = f.share();
+ return std::async(std::launch::deferred, [=]() mutable -> typename std::decay<decltype(f.get().get())>::type
+ {
+ return shared_f.get().get();
+ });
+}
+
+template<typename F>
+bool is_ready(const F& future)
+{
+ return future.wait_for(std::chrono::seconds(0)) == std::future_status::ready;
+}
+
+/**
+ * Wrap a value in a future with an already known result.
+ * <p>
+ * Useful when the result of an operation is already known at the time of
+ * calling.
+ *
+ * @param value The r-value to wrap.
+ *
+ * @return The future with the result set.
+ */
+template<class R>
+std::future<R> make_ready_future(R&& value)
+{
+ std::promise<R> p;
+
+ p.set_value(value);
+
+ return p.get_future();
+}
+
+static std::future<void> make_ready_future()
+{
+ std::promise<void> p;
+
+ p.set_value();
+
+ return p.get_future();
+}
+
}
\ No newline at end of file
projects / casparcg / blobdiff