hhook.go

package wingo

import (
	"github.com/rogeecn/wingo/proc"
	"syscall"

	"github.com/rogeecn/wingo/co"
	"github.com/rogeecn/wingo/errco"
)

// A handle to a hook.
//
// Note that this callback is recreated each function call, and the number of
// system callbacks is limited somewhere by the Go runtime.
//
// 📑 https://docs.microsoft.com/en-us/windows/win32/winprog/windows-data-types#hhook
type HHOOK HANDLE

// 📑 https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setwindowshookexw
func SetWindowsHookEx(idHook co.WH,
	userFunc func(code int32, wp WPARAM, lp LPARAM) uintptr,
	hMod HINSTANCE, threadId uint32) HHOOK {

	ret, _, err := syscall.Syscall6(proc.SetWindowsHookEx.Addr(), 4,
		uintptr(idHook), syscall.NewCallback(userFunc),
		uintptr(hMod), uintptr(threadId), 0, 0)
	if ret == 0 {
		panic(errco.ERROR(err))
	}
	return HHOOK(ret)
}

// 📑 https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-callnexthookex
func (hHook HHOOK) CallNextHookEx(nCode int32, wp WPARAM, lp LPARAM) uintptr {
	ret, _, _ := syscall.Syscall6(proc.CallNextHookEx.Addr(), 4,
		uintptr(hHook), uintptr(nCode), uintptr(wp), uintptr(lp), 0, 0)
	return uintptr(ret)
}

// 📑 https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-unhookwindowshookex
func (hHook HHOOK) UnhookWindowsHookEx() {
	ret, _, err := syscall.Syscall(proc.UnhookWindowsHookEx.Addr(), 1,
		uintptr(hHook), 0, 0)
	if ret == 0 {
		panic(errco.ERROR(err))
	}
}