1 files changed, 177 insertions, 0 deletions
diff --git a/src/time/sleep.go b/src/time/sleep.go
new file mode 100644
index 0000000..1ffaabe
--- /dev/null
+++ b/src/time/sleep.go
@@ -0,0 +1,177 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package time
+
+// Sleep pauses the current goroutine for at least the duration d.
+// A negative or zero duration causes Sleep to return immediately.
+func Sleep(d Duration)
+
+// Interface to timers implemented in package runtime.
+// Must be in sync with ../runtime/time.go:/^type timer
+type runtimeTimer struct {
+	pp       uintptr
+	when     int64
+	period   int64
+	f        func(any, uintptr) // NOTE: must not be closure
+	arg      any
+	seq      uintptr
+	nextwhen int64
+	status   uint32
+}
+
+// when is a helper function for setting the 'when' field of a runtimeTimer.
+// It returns what the time will be, in nanoseconds, Duration d in the future.
+// If d is negative, it is ignored. If the returned value would be less than
+// zero because of an overflow, MaxInt64 is returned.
+func when(d Duration) int64 {
+	if d <= 0 {
+		return runtimeNano()
+	}
+	t := runtimeNano() + int64(d)
+	if t < 0 {
+		// N.B. runtimeNano() and d are always positive, so addition
+		// (including overflow) will never result in t == 0.
+		t = 1<<63 - 1 // math.MaxInt64
+	}
+	return t
+}
+
+func startTimer(*runtimeTimer)
+func stopTimer(*runtimeTimer) bool
+func resetTimer(*runtimeTimer, int64) bool
+func modTimer(t *runtimeTimer, when, period int64, f func(any, uintptr), arg any, seq uintptr)
+
+// The Timer type represents a single event.
+// When the Timer expires, the current time will be sent on C,
+// unless the Timer was created by AfterFunc.
+// A Timer must be created with NewTimer or AfterFunc.
+type Timer struct {
+	C <-chan Time
+	r runtimeTimer
+}
+
+// Stop prevents the Timer from firing.
+// It returns true if the call stops the timer, false if the timer has already
+// expired or been stopped.
+// Stop does not close the channel, to prevent a read from the channel succeeding
+// incorrectly.
+//
+// To ensure the channel is empty after a call to Stop, check the
+// return value and drain the channel.
+// For example, assuming the program has not received from t.C already:
+//
+// 	if !t.Stop() {
+// 		<-t.C
+// 	}
+//
+// This cannot be done concurrent to other receives from the Timer's
+// channel or other calls to the Timer's Stop method.
+//
+// For a timer created with AfterFunc(d, f), if t.Stop returns false, then the timer
+// has already expired and the function f has been started in its own goroutine;
+// Stop does not wait for f to complete before returning.
+// If the caller needs to know whether f is completed, it must coordinate
+// with f explicitly.
+func (t *Timer) Stop() bool {
+	if t.r.f == nil {
+		panic("time: Stop called on uninitialized Timer")
+	}
+	return stopTimer(&t.r)
+}
+
+// NewTimer creates a new Timer that will send
+// the current time on its channel after at least duration d.
+func NewTimer(d Duration) *Timer {
+	c := make(chan Time, 1)
+	t := &Timer{
+		C: c,
+		r: runtimeTimer{
+			when: when(d),
+			f:    sendTime,
+			arg:  c,
+		},
+	}
+	startTimer(&t.r)
+	return t
+}
+
+// Reset changes the timer to expire after duration d.
+// It returns true if the timer had been active, false if the timer had
+// expired or been stopped.
+//
+// For a Timer created with NewTimer, Reset should be invoked only on
+// stopped or expired timers with drained channels.
+//
+// If a program has already received a value from t.C, the timer is known
+// to have expired and the channel drained, so t.Reset can be used directly.
+// If a program has not yet received a value from t.C, however,
+// the timer must be stopped and—if Stop reports that the timer expired
+// before being stopped—the channel explicitly drained:
+//
+// 	if !t.Stop() {
+// 		<-t.C
+// 	}
+// 	t.Reset(d)
+//
+// This should not be done concurrent to other receives from the Timer's
+// channel.
+//
+// Note that it is not possible to use Reset's return value correctly, as there
+// is a race condition between draining the channel and the new timer expiring.
+// Reset should always be invoked on stopped or expired channels, as described above.
+// The return value exists to preserve compatibility with existing programs.
+//
+// For a Timer created with AfterFunc(d, f), Reset either reschedules
+// when f will run, in which case Reset returns true, or schedules f
+// to run again, in which case it returns false.
+// When Reset returns false, Reset neither waits for the prior f to
+// complete before returning nor does it guarantee that the subsequent
+// goroutine running f does not run concurrently with the prior
+// one. If the caller needs to know whether the prior execution of
+// f is completed, it must coordinate with f explicitly.
+func (t *Timer) Reset(d Duration) bool {
+	if t.r.f == nil {
+		panic("time: Reset called on uninitialized Timer")
+	}
+	w := when(d)
+	return resetTimer(&t.r, w)
+}
+
+// sendTime does a non-blocking send of the current time on c.
+func sendTime(c any, seq uintptr) {
+	select {
+	case c.(chan Time) <- Now():
+	default:
+	}
+}
+
+// After waits for the duration to elapse and then sends the current time
+// on the returned channel.
+// It is equivalent to NewTimer(d).C.
+// The underlying Timer is not recovered by the garbage collector
+// until the timer fires. If efficiency is a concern, use NewTimer
+// instead and call Timer.Stop if the timer is no longer needed.
+func After(d Duration) <-chan Time {
+	return NewTimer(d).C
+}
+
+// AfterFunc waits for the duration to elapse and then calls f
+// in its own goroutine. It returns a Timer that can
+// be used to cancel the call using its Stop method.
+func AfterFunc(d Duration, f func()) *Timer {
+	t := &Timer{
+		r: runtimeTimer{
+			when: when(d),
+			f:    goFunc,
+			arg:  f,
+		},
+	}
+	startTimer(&t.r)
+	return t
+}
+
+func goFunc(arg any, seq uintptr) {
+	go arg.(func())()
+}