github.com/apernet/quic-go@v0.43.1-0.20240515053213-5e9e635fd9f0/internal/utils/timer.go (about)

     1  package utils
     2  
     3  import (
     4  	"math"
     5  	"time"
     6  )
     7  
     8  // A Timer wrapper that behaves correctly when resetting
     9  type Timer struct {
    10  	t        *time.Timer
    11  	read     bool
    12  	deadline time.Time
    13  }
    14  
    15  // NewTimer creates a new timer that is not set
    16  func NewTimer() *Timer {
    17  	return &Timer{t: time.NewTimer(time.Duration(math.MaxInt64))}
    18  }
    19  
    20  // Chan returns the channel of the wrapped timer
    21  func (t *Timer) Chan() <-chan time.Time {
    22  	return t.t.C
    23  }
    24  
    25  // Reset the timer, no matter whether the value was read or not
    26  func (t *Timer) Reset(deadline time.Time) {
    27  	if deadline.Equal(t.deadline) && !t.read {
    28  		// No need to reset the timer
    29  		return
    30  	}
    31  
    32  	// We need to drain the timer if the value from its channel was not read yet.
    33  	// See https://groups.google.com/forum/#!topic/golang-dev/c9UUfASVPoU
    34  	if !t.t.Stop() && !t.read {
    35  		<-t.t.C
    36  	}
    37  	if !deadline.IsZero() {
    38  		t.t.Reset(time.Until(deadline))
    39  	}
    40  
    41  	t.read = false
    42  	t.deadline = deadline
    43  }
    44  
    45  // SetRead should be called after the value from the chan was read
    46  func (t *Timer) SetRead() {
    47  	t.read = true
    48  }
    49  
    50  func (t *Timer) Deadline() time.Time {
    51  	return t.deadline
    52  }
    53  
    54  // Stop stops the timer
    55  func (t *Timer) Stop() {
    56  	t.t.Stop()
    57  }