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