github.com/cryptogateway/go-paymex@v0.0.0-20210204174735-96277fb1e602/les/utils/timeutils.go (about)

     1  // Copyright 2020 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 utils
    18  
    19  import (
    20  	"sync"
    21  	"time"
    22  
    23  	"github.com/cryptogateway/go-paymex/common/mclock"
    24  )
    25  
    26  type UpdateTimer struct {
    27  	clock     mclock.Clock
    28  	lock      sync.Mutex
    29  	last      mclock.AbsTime
    30  	threshold time.Duration
    31  }
    32  
    33  func NewUpdateTimer(clock mclock.Clock, threshold time.Duration) *UpdateTimer {
    34  	// We don't accept the update threshold less than 0.
    35  	if threshold < 0 {
    36  		return nil
    37  	}
    38  	// Don't panic for lazy users
    39  	if clock == nil {
    40  		clock = mclock.System{}
    41  	}
    42  	return &UpdateTimer{
    43  		clock:     clock,
    44  		last:      clock.Now(),
    45  		threshold: threshold,
    46  	}
    47  }
    48  
    49  func (t *UpdateTimer) Update(callback func(diff time.Duration) bool) bool {
    50  	return t.UpdateAt(t.clock.Now(), callback)
    51  }
    52  
    53  func (t *UpdateTimer) UpdateAt(at mclock.AbsTime, callback func(diff time.Duration) bool) bool {
    54  	t.lock.Lock()
    55  	defer t.lock.Unlock()
    56  
    57  	diff := time.Duration(at - t.last)
    58  	if diff < 0 {
    59  		diff = 0
    60  	}
    61  	if diff < t.threshold {
    62  		return false
    63  	}
    64  	if callback(diff) {
    65  		t.last = at
    66  		return true
    67  	}
    68  	return false
    69  }