lbcwallet/signal.go
2016-02-28 22:22:34 -05:00

80 lines
2.3 KiB
Go

// Copyright (c) 2013-2014 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package main
import (
"os"
"os/signal"
)
// interruptChannel is used to receive SIGINT (Ctrl+C) signals.
var interruptChannel chan os.Signal
// addHandlerChannel is used to add an interrupt handler to the list of handlers
// to be invoked on SIGINT (Ctrl+C) signals.
var addHandlerChannel = make(chan func())
// interruptHandlersDone is closed after all interrupt handlers run the first
// time an interrupt is signaled.
var interruptHandlersDone = make(chan struct{})
var simulateInterruptChannel = make(chan struct{}, 1)
// simulateInterrupt requests invoking the clean termination process by an
// internal component instead of a SIGINT.
func simulateInterrupt() {
select {
case simulateInterruptChannel <- struct{}{}:
default:
}
}
// mainInterruptHandler listens for SIGINT (Ctrl+C) signals on the
// interruptChannel and invokes the registered interruptCallbacks accordingly.
// It also listens for callback registration. It must be run as a goroutine.
func mainInterruptHandler() {
// interruptCallbacks is a list of callbacks to invoke when a
// SIGINT (Ctrl+C) is received.
var interruptCallbacks []func()
invokeCallbacks := func() {
// run handlers in LIFO order.
for i := range interruptCallbacks {
idx := len(interruptCallbacks) - 1 - i
interruptCallbacks[idx]()
}
close(interruptHandlersDone)
}
for {
select {
case <-interruptChannel:
log.Info("Received SIGINT (Ctrl+C). Shutting down...")
invokeCallbacks()
return
case <-simulateInterruptChannel:
log.Info("Received shutdown request. Shutting down...")
invokeCallbacks()
return
case handler := <-addHandlerChannel:
interruptCallbacks = append(interruptCallbacks, handler)
}
}
}
// addInterruptHandler adds a handler to call when a SIGINT (Ctrl+C) is
// received.
func addInterruptHandler(handler func()) {
// Create the channel and start the main interrupt handler which invokes
// all other callbacks and exits if not already done.
if interruptChannel == nil {
interruptChannel = make(chan os.Signal, 1)
signal.Notify(interruptChannel, os.Interrupt)
go mainInterruptHandler()
}
addHandlerChannel <- handler
}