system/PeriodClock: move to time/

src/system/PeriodClock.hxx

@@ -1,135 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-// Copyright The Music Player Daemon Project
-
-#ifndef MPD_PERIOD_CLOCK_HXX
-#define MPD_PERIOD_CLOCK_HXX
-
-#include <chrono>
-
-/**
- * This is a stopwatch which saves the timestamp of an event, and can
- * check whether a specified time span has passed since then.
- */
-class PeriodClock {
-public:
-	typedef std::chrono::steady_clock::duration Duration;
-	typedef Duration Delta;
-	typedef std::chrono::steady_clock::time_point Stamp;
-
-private:
-	Stamp last;
-
-public:
-	/**
-	 * Initializes the object, setting the last time stamp to "0",
-	 * i.e. a Check() will always succeed.  If you do not want this
-	 * default behaviour, call Update() immediately after creating the
-	 * object.
-	 */
-	constexpr
-	PeriodClock():last() {}
-
-protected:
-	static Stamp GetNow() {
-		return std::chrono::steady_clock::now();
-	}
-
-	constexpr Delta Elapsed(Stamp now) const {
-		return last == Stamp()
-			? Delta(-1)
-			: Delta(now - last);
-	}
-
-	constexpr bool Check(Stamp now, Duration duration) const {
-		return now >= last + duration;
-	}
-
-	void Update(Stamp now) {
-		last = now;
-	}
-
-public:
-	constexpr bool IsDefined() const {
-		return last > Stamp();
-	}
-
-	/**
-	 * Resets the clock.
-	 */
-	void Reset() {
-		last = Stamp();
-	}
-
-	/**
-	 * Returns the time elapsed since the last update().  Returns
-	 * a negative value if update() was never called.
-	 */
-	Delta Elapsed() const {
-		return Elapsed(GetNow());
-	}
-
-	/**
-	 * Combines a call to Elapsed() and Update().
-	 */
-	Delta ElapsedUpdate() {
-		const auto now = GetNow();
-		const auto result = Elapsed(now);
-		Update(now);
-		return result;
-	}
-
-	/**
-	 * Checks whether the specified duration has passed since the last
-	 * update.
-	 *
-	 * @param duration the duration
-	 */
-	bool Check(Duration duration) const {
-		return Check(GetNow(), duration);
-	}
-
-	/**
-	 * Updates the time stamp, setting it to the current clock.
-	 */
-	void Update() {
-		Update(GetNow());
-	}
-
-	/**
-	 * Updates the time stamp, setting it to the current clock plus the
-	 * specified offset.
-	 */
-	void UpdateWithOffset(Delta offset) {
-		Update(GetNow() + offset);
-	}
-
-	/**
-	 * Checks whether the specified duration has passed since the last
-	 * update.  If yes, it updates the time stamp.
-	 *
-	 * @param duration the duration in milliseconds
-	 */
-	bool CheckUpdate(Duration duration) {
-		Stamp now = GetNow();
-		if (Check(now, duration)) {
-			Update(now);
-			return true;
-		} else
-			return false;
-	}
-
-	/**
-	 * Checks whether the specified duration has passed since the last
-	 * update.  After that, it updates the time stamp.
-	 *
-	 * @param duration the duration in milliseconds
-	 */
-	bool CheckAlwaysUpdate(Duration duration) {
-		Stamp now = GetNow();
-		bool ret = Check(now, duration);
-		Update(now);
-		return ret;
-	}
-};
-
-#endif