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