github.com/theQRL/go-zond@v0.1.1/common/mclock/mclock.go (about)

     1  // Copyright 2016 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  // Package mclock is a wrapper for a monotonic clock source
    18  package mclock
    19  
    20  import (
    21  	"time"
    22  
    23  	_ "unsafe" // for go:linkname
    24  )
    25  
    26  //go:noescape
    27  //go:linkname nanotime runtime.nanotime
    28  func nanotime() int64
    29  
    30  // AbsTime represents absolute monotonic time.
    31  type AbsTime int64
    32  
    33  // Now returns the current absolute monotonic time.
    34  func Now() AbsTime {
    35  	return AbsTime(nanotime())
    36  }
    37  
    38  // Add returns t + d as absolute time.
    39  func (t AbsTime) Add(d time.Duration) AbsTime {
    40  	return t + AbsTime(d)
    41  }
    42  
    43  // Sub returns t - t2 as a duration.
    44  func (t AbsTime) Sub(t2 AbsTime) time.Duration {
    45  	return time.Duration(t - t2)
    46  }
    47  
    48  // The Clock interface makes it possible to replace the monotonic system clock with
    49  // a simulated clock.
    50  type Clock interface {
    51  	Now() AbsTime
    52  	Sleep(time.Duration)
    53  	NewTimer(time.Duration) ChanTimer
    54  	After(time.Duration) <-chan AbsTime
    55  	AfterFunc(d time.Duration, f func()) Timer
    56  }
    57  
    58  // Timer is a cancellable event created by AfterFunc.
    59  type Timer interface {
    60  	// Stop cancels the timer. It returns false if the timer has already
    61  	// expired or been stopped.
    62  	Stop() bool
    63  }
    64  
    65  // ChanTimer is a cancellable event created by NewTimer.
    66  type ChanTimer interface {
    67  	Timer
    68  
    69  	// The channel returned by C receives a value when the timer expires.
    70  	C() <-chan AbsTime
    71  	// Reset reschedules the timer with a new timeout.
    72  	// It should be invoked only on stopped or expired timers with drained channels.
    73  	Reset(time.Duration)
    74  }
    75  
    76  // System implements Clock using the system clock.
    77  type System struct{}
    78  
    79  // Now returns the current monotonic time.
    80  func (c System) Now() AbsTime {
    81  	return Now()
    82  }
    83  
    84  // Sleep blocks for the given duration.
    85  func (c System) Sleep(d time.Duration) {
    86  	time.Sleep(d)
    87  }
    88  
    89  // NewTimer creates a timer which can be rescheduled.
    90  func (c System) NewTimer(d time.Duration) ChanTimer {
    91  	ch := make(chan AbsTime, 1)
    92  	t := time.AfterFunc(d, func() {
    93  		// This send is non-blocking because that's how time.Timer
    94  		// behaves. It doesn't matter in the happy case, but does
    95  		// when Reset is misused.
    96  		select {
    97  		case ch <- c.Now():
    98  		default:
    99  		}
   100  	})
   101  	return &systemTimer{t, ch}
   102  }
   103  
   104  // After returns a channel which receives the current time after d has elapsed.
   105  func (c System) After(d time.Duration) <-chan AbsTime {
   106  	ch := make(chan AbsTime, 1)
   107  	time.AfterFunc(d, func() { ch <- c.Now() })
   108  	return ch
   109  }
   110  
   111  // AfterFunc runs f on a new goroutine after the duration has elapsed.
   112  func (c System) AfterFunc(d time.Duration, f func()) Timer {
   113  	return time.AfterFunc(d, f)
   114  }
   115  
   116  type systemTimer struct {
   117  	*time.Timer
   118  	ch <-chan AbsTime
   119  }
   120  
   121  func (st *systemTimer) Reset(d time.Duration) {
   122  	st.Timer.Reset(d)
   123  }
   124  
   125  func (st *systemTimer) C() <-chan AbsTime {
   126  	return st.ch
   127  }