f439dece37
With semaphores we don't actually care about the value passed in. It makes sense to use a 0 bytes type in these cases. There is also the added benefit of compiler optimisations for this specific use case as described here: https://docs.google.com/document/d/1yIAYmbvL3JxOKOjuCyon7JhW4cSv1wy5hC0ApeGMV9s/pub
60 lines
1.7 KiB
Go
60 lines
1.7 KiB
Go
// Copyright (c) 2013-2014 Conformal Systems LLC.
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package main
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import (
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"os"
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"os/signal"
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)
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// interruptChannel is used to receive SIGINT (Ctrl+C) signals.
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var interruptChannel chan os.Signal
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// addHandlerChannel is used to add an interrupt handler to the list of handlers
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// to be invoked on SIGINT (Ctrl+C) signals.
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var addHandlerChannel = make(chan func())
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// mainInterruptHandler listens for SIGINT (Ctrl+C) signals on the
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// interruptChannel and invokes the registered interruptCallbacks accordingly.
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// It also listens for callback registration. It must be run as a goroutine.
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func mainInterruptHandler() {
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// interruptCallbacks is a list of callbacks to invoke when a
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// SIGINT (Ctrl+C) is received.
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var interruptCallbacks []func()
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for {
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select {
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case <-interruptChannel:
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btcdLog.Infof("Received SIGINT (Ctrl+C). Shutting down...")
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// run handlers in LIFO order.
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for i := range interruptCallbacks {
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idx := len(interruptCallbacks) - 1 - i
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callback := interruptCallbacks[idx]
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callback()
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}
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// Signal the main goroutine to shutdown.
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shutdownChannel <- struct{}{}
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case handler := <-addHandlerChannel:
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interruptCallbacks = append(interruptCallbacks, handler)
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}
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}
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}
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// addInterruptHandler adds a handler to call when a SIGINT (Ctrl+C) is
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// received.
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func addInterruptHandler(handler func()) {
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// Create the channel and start the main interrupt handler which invokes
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// all other callbacks and exits if not already done.
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if interruptChannel == nil {
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interruptChannel = make(chan os.Signal, 1)
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signal.Notify(interruptChannel, os.Interrupt)
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go mainInterruptHandler()
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}
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addHandlerChannel <- handler
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}
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