wait_time.go

Documentation: go.etcd.io/etcd/pkg/v3/wait

     1  // Copyright 2015 The etcd Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package wait
    16  
    17  import "sync"
    18  
    19  type WaitTime interface {
    20  	// Wait returns a chan that waits on the given logical deadline.
    21  	// The chan will be triggered when Trigger is called with a
    22  	// deadline that is later than the one it is waiting for.
    23  	Wait(deadline uint64) <-chan struct{}
    24  	// Trigger triggers all the waiting chans with an earlier logical deadline.
    25  	Trigger(deadline uint64)
    26  }
    27  
    28  var closec chan struct{}
    29  
    30  func init() { closec = make(chan struct{}); close(closec) }
    31  
    32  type timeList struct {
    33  	l                   sync.Mutex
    34  	lastTriggerDeadline uint64
    35  	m                   map[uint64]chan struct{}
    36  }
    37  
    38  func NewTimeList() *timeList {
    39  	return &timeList{m: make(map[uint64]chan struct{})}
    40  }
    41  
    42  func (tl *timeList) Wait(deadline uint64) <-chan struct{} {
    43  	tl.l.Lock()
    44  	defer tl.l.Unlock()
    45  	if tl.lastTriggerDeadline >= deadline {
    46  		return closec
    47  	}
    48  	ch := tl.m[deadline]
    49  	if ch == nil {
    50  		ch = make(chan struct{})
    51  		tl.m[deadline] = ch
    52  	}
    53  	return ch
    54  }
    55  
    56  func (tl *timeList) Trigger(deadline uint64) {
    57  	tl.l.Lock()
    58  	defer tl.l.Unlock()
    59  	tl.lastTriggerDeadline = deadline
    60  	for t, ch := range tl.m {
    61  		if t <= deadline {
    62  			delete(tl.m, t)
    63  			close(ch)
    64  		}
    65  	}
    66  }
    67
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