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/*
*
* Copyright 2018 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
// Package grpcsync implements additional synchronization primitives built upon
// the sync package.
package grpcsync
import (
"sync"
"sync/atomic"
)
// Event represents a one-time event that may occur in the future.
type Event struct {
fired int32
c chan struct{}
o sync.Once
}
// Fire causes e to complete. It is safe to call multiple times, and
// concurrently. It returns true iff this call to Fire caused the signaling
// channel returned by Done to close.
func (e *Event) Fire() bool {
ret := false
e.o.Do(func() {
atomic.StoreInt32(&e.fired, 1)
close(e.c)
ret = true
})
return ret
}
// Done returns a channel that will be closed when Fire is called.
func (e *Event) Done() <-chan struct{} {
return e.c
}
// HasFired returns true if Fire has been called.
func (e *Event) HasFired() bool {
return atomic.LoadInt32(&e.fired) == 1
}
// NewEvent returns a new, ready-to-use Event.
func NewEvent() *Event {
return &Event{c: make(chan struct{})}
}
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