go.temporal.io/server@v1.23.0/common/channel/shutdown_once.go (about) 1 // The MIT License 2 // 3 // Copyright (c) 2020 Temporal Technologies Inc. All rights reserved. 4 // 5 // Copyright (c) 2020 Uber Technologies, Inc. 6 // 7 // Permission is hereby granted, free of charge, to any person obtaining a copy 8 // of this software and associated documentation files (the "Software"), to deal 9 // in the Software without restriction, including without limitation the rights 10 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11 // copies of the Software, and to permit persons to whom the Software is 12 // furnished to do so, subject to the following conditions: 13 // 14 // The above copyright notice and this permission notice shall be included in 15 // all copies or substantial portions of the Software. 16 // 17 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 20 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 23 // THE SOFTWARE. 24 25 package channel 26 27 import ( 28 "sync/atomic" 29 ) 30 31 const ( 32 shutdownOnceStatusOpen int32 = 0 33 shutdownOnceStatusClosed int32 = 1 34 ) 35 36 type ( 37 ShutdownOnce interface { 38 // Shutdown broadcast shutdown signal 39 Shutdown() 40 // IsShutdown return true if already shutdown 41 IsShutdown() bool 42 // Channel for shutdown notification 43 Channel() <-chan struct{} 44 } 45 46 ShutdownOnceImpl struct { 47 status int32 48 channel chan struct{} 49 } 50 ) 51 52 func NewShutdownOnce() *ShutdownOnceImpl { 53 return &ShutdownOnceImpl{ 54 status: shutdownOnceStatusOpen, 55 channel: make(chan struct{}), 56 } 57 } 58 59 func (c *ShutdownOnceImpl) Shutdown() { 60 if atomic.CompareAndSwapInt32( 61 &c.status, 62 shutdownOnceStatusOpen, 63 shutdownOnceStatusClosed, 64 ) { 65 close(c.channel) 66 } 67 } 68 69 func (c *ShutdownOnceImpl) IsShutdown() bool { 70 return atomic.LoadInt32(&c.status) == shutdownOnceStatusClosed 71 } 72 73 func (c *ShutdownOnceImpl) Channel() <-chan struct{} { 74 return c.channel 75 }