Add winpowrprof package

common/winpowrprof/event.go

@@ -0,0 +1,12 @@
+package winpowrprof
+
+const (
+	EVENT_SUSPEND = iota
+	EVENT_RESUME
+	EVENT_RESUME_AUTOMATIC // Because the user is not present, most applications should do nothing.
+)
+
+type EventListener interface {
+	Start() error
+	Close() error
+}

common/winpowrprof/event_stub.go

@@ -0,0 +1,11 @@
+//go:build !windows
+
+package winpowrprof
+
+import (
+	"os"
+)
+
+func NewEventListener(callback func(event int)) (EventListener, error) {
+	return nil, os.ErrInvalid
+}

common/winpowrprof/event_test.go

@@ -0,0 +1,19 @@
+package winpowrprof
+
+import (
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPowerEvents(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.SkipNow()
+	}
+	listener, err := NewEventListener(func(event int) {})
+	require.NoError(t, err)
+	require.NotNil(t, listener)
+	require.NoError(t, listener.Start())
+	require.NoError(t, listener.Close())
+}

common/winpowrprof/event_windows.go

@@ -0,0 +1,83 @@
+package winpowrprof
+
+// modify from https://github.com/golang/go/blob/b634f6fdcbebee23b7da709a243f3db217b64776/src/runtime/os_windows.go#L257
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var (
+	modpowerprof                                 = windows.NewLazySystemDLL("powrprof.dll")
+	procPowerRegisterSuspendResumeNotification   = modpowerprof.NewProc("PowerRegisterSuspendResumeNotification")
+	procPowerUnregisterSuspendResumeNotification = modpowerprof.NewProc("PowerUnregisterSuspendResumeNotification")
+)
+
+const (
+	PBT_APMSUSPEND         uint32 = 4
+	PBT_APMRESUMESUSPEND   uint32 = 7
+	PBT_APMRESUMEAUTOMATIC uint32 = 18
+)
+
+const (
+	_DEVICE_NOTIFY_CALLBACK = 2
+)
+
+type _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS struct {
+	callback uintptr
+	context  uintptr
+}
+
+type eventListener struct {
+	params _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS
+	handle uintptr
+}
+
+func NewEventListener(callback func(event int)) (EventListener, error) {
+	if err := procPowerRegisterSuspendResumeNotification.Find(); err != nil {
+		return nil, err // Running on Windows 7, where we don't need it anyway.
+	}
+	if err := procPowerUnregisterSuspendResumeNotification.Find(); err != nil {
+		return nil, err // Running on Windows 7, where we don't need it anyway.
+	}
+
+	var fn interface{} = func(context uintptr, changeType uint32, setting uintptr) uintptr {
+		switch changeType {
+		case PBT_APMSUSPEND:
+			callback(EVENT_SUSPEND)
+		case PBT_APMRESUMESUSPEND:
+			callback(EVENT_RESUME)
+		case PBT_APMRESUMEAUTOMATIC:
+			callback(EVENT_RESUME_AUTOMATIC)
+		}
+		return 0
+	}
+	return &eventListener{
+		params: _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS{
+			callback: windows.NewCallback(fn),
+		},
+	}, nil
+}
+
+func (l *eventListener) Start() error {
+	_, _, errno := syscall.SyscallN(
+		procPowerRegisterSuspendResumeNotification.Addr(),
+		_DEVICE_NOTIFY_CALLBACK,
+		uintptr(unsafe.Pointer(&l.params)),
+		uintptr(unsafe.Pointer(&l.handle)),
+	)
+	if errno != 0 {
+		return errno
+	}
+	return nil
+}
+
+func (l *eventListener) Close() error {
+	_, _, errno := syscall.SyscallN(procPowerUnregisterSuspendResumeNotification.Addr(), uintptr(unsafe.Pointer(&l.handle)))
+	if errno != 0 {
+		return errno
+	}
+	return nil
+}