Added support for signaler under Windows platform

**Note** Untested, code compiles and logic is present, but it was not tested (yet) under
Windows platform. It might not even be necessary at all since the console behavior could
already be correct on Windows.

.gitignore

@@ -4,3 +4,5 @@
 ## Go
 /dist
 /vendor
+/zap-pretty
+/zap-pretty.exe

go.mod

@@ -3,6 +3,7 @@ module github.com/maoueh/zap-pretty
 require (
 	github.com/logrusorgru/aurora v0.0.0-20181002194514-a7b3b318ed4e
 	github.com/stretchr/testify v1.3.0
+	golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e
 )
 
 go 1.13

go.sum

@@ -7,3 +7,5 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e h1:LwyF2AFISC9nVbS6MgzsaQNSUsRXI49GS+YQ5KX/QH0=
+golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

signaler.go → signaler_others.go

@@ -1,3 +1,5 @@
+//+build darwin linux
+
 package main
 
 import (

signaler_windows.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"golang.org/x/sys/windows"
+)
+
+type signaler struct {
+}
+
+func NewSignaler() *signaler {
+	return &signaler{}
+}
+
+func (s *signaler) forwardAllSignalsToProcessGroup() {
+	consoleCtrlEventChan := make(chan uint, 1)
+	if err := handleConsoleCtrlEvent(consoleCtrlEventChan); err != nil {
+		debug.Println("[Warning] unable to listen for console events")
+		return
+	}
+
+	for {
+		ctrlType := <-consoleCtrlEventChan
+
+		// The MSDN documentation for this call states the following:
+		//
+		// > If this parameter is zero, the signal is generated in all processes
+		//   that share the console of the calling process.
+		//
+		// In our case, it's exactly what we want to do, we want to forward to all process in
+		// group, so hence the `0` hard-coded value.
+		//
+		// @see https://docs.microsoft.com/en-us/windows/console/generateconsolectrlevent
+		windows.GenerateConsoleCtrlEvent(uint32(ctrlType), 0)
+	}
+}
+
+// Code for windows console handler based on https://github.com/golang/go/issues/7479#issuecomment-457669779
+func handleConsoleCtrlEvent(events chan<- uint) error {
+	kernel32 := windows.NewLazySystemDLL("kernel32.dll")
+	setConsoleCtrlHandler := kernel32.NewProc("SetConsoleCtrlHandler")
+	callback := func(ctrlType uint) uint {
+		events <- ctrlType
+		return 0
+	}
+
+
+	n, _, err := setConsoleCtrlHandler.Call(windows.NewCallback(callback), 1)
+	if n == 0 {
+		return err
+	}
+
+	return nil
+}