// SPDX-License-Identifier: GPL-2.0-or-later // Copyright The Music Player Daemon Project #ifndef MPD_LAST_INPUT_STREAM_HXX #define MPD_LAST_INPUT_STREAM_HXX #include "Ptr.hxx" #include "thread/Mutex.hxx" #include "event/CoarseTimerEvent.hxx" #include /** * A helper class which maintains an #InputStream that is opened once * and may be reused later for some time. It will be closed * automatically after some time. * * This class is not thread-safe. All methods must be called on the * thread which runs the #EventLoop. */ class LastInputStream { std::string uri; Mutex mutex; InputStreamPtr is; CoarseTimerEvent close_timer; public: explicit LastInputStream(EventLoop &event_loop) noexcept; ~LastInputStream() noexcept; /** * Open an #InputStream instance with the given opener * function, but returns the cached instance if it matches. * * This object keeps owning the #InputStream; the caller shall * not close it. */ template InputStream *Open(U &&new_uri, O &&open) { if (new_uri == uri) { if (is) /* refresh the timeout */ ScheduleClose(); return is.get(); } Close(); is = open(new_uri, mutex); uri = std::forward(new_uri); if (is) ScheduleClose(); return is.get(); } void Close() noexcept; private: void ScheduleClose() noexcept { close_timer.Schedule(std::chrono::seconds(20)); } void OnCloseTimer() noexcept; }; #endif