app/internal/windows: add SendMessage, FindWindow

Also replace calls to the deprecated StringToUTF16Ptr syscall.

Signed-off-by: inkeliz <inkeliz@inkeliz.com>
Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/internal/windows/windows.go

@@ -108,6 +108,12 @@ type MonitorInfo struct {
 	Flags    uint32
 }
 
+type CopyDataStruct struct {
+	DwData uintptr
+	CbData uint32
+	LpData uintptr
+}
+
 type POINTER_INPUT_TYPE int32
 
 const (
@@ -315,6 +321,7 @@ const (
 	WM_CANCELMODE            = 0x001F
 	WM_CHAR                  = 0x0102
 	WM_CLOSE                 = 0x0010
+	WM_COPYDATA              = 0x004A
 	WM_CREATE                = 0x0001
 	WM_DPICHANGED            = 0x02E0
 	WM_DESTROY               = 0x0002
@@ -419,6 +426,7 @@ var (
 	_DefWindowProc               = user32.NewProc("DefWindowProcW")
 	_DestroyWindow               = user32.NewProc("DestroyWindow")
 	_DispatchMessage             = user32.NewProc("DispatchMessageW")
+	_FindWindow                  = user32.NewProc("FindWindowW")
 	_EmptyClipboard              = user32.NewProc("EmptyClipboard")
 	_EnableMouseInPointer        = user32.NewProc("EnableMouseInPointer")
 	_GetWindowRect               = user32.NewProc("GetWindowRect")
@@ -452,6 +460,7 @@ var (
 	_ReleaseDC                   = user32.NewProc("ReleaseDC")
 	_ScreenToClient              = user32.NewProc("ScreenToClient")
 	_ShowWindow                  = user32.NewProc("ShowWindow")
+	_SendMessage                 = user32.NewProc("SendMessageW")
 	_SetCapture                  = user32.NewProc("SetCapture")
 	_SetCursor                   = user32.NewProc("SetCursor")
 	_SetClipboardData            = user32.NewProc("SetClipboardData")
@@ -504,7 +513,10 @@ func CloseClipboard() error {
 }
 
 func CreateWindowEx(dwExStyle uint32, lpClassName uint16, lpWindowName string, dwStyle uint32, x, y, w, h int32, hWndParent, hMenu, hInstance syscall.Handle, lpParam uintptr) (syscall.Handle, error) {
-	wname := syscall.StringToUTF16Ptr(lpWindowName)
+	wname, err := syscall.UTF16PtrFromString(lpWindowName)
+	if err != nil {
+		return 0, fmt.Errorf("CreateWindowEx failed: %v", err)
+	}
 	hwnd, _, err := _CreateWindowEx.Call(
 		uintptr(dwExStyle),
 		uintptr(lpClassName),
@@ -576,6 +588,18 @@ func EmptyClipboard() error {
 	return nil
 }
 
+func FindWindow(lpClassName string) (syscall.Handle, error) {
+	className, err := syscall.UTF16PtrFromString(lpClassName)
+	if err != nil {
+		return 0, fmt.Errorf("FindWindow failed: %v", err)
+	}
+	hwnd, _, err := _FindWindow.Call(uintptr(unsafe.Pointer(className)), 0)
+	if hwnd == 0 {
+		return 0, fmt.Errorf("FindWindow failed: %v", err)
+	}
+	return syscall.Handle(hwnd), nil
+}
+
 func GetWindowRect(hwnd syscall.Handle) Rect {
 	var r Rect
 	_GetWindowRect.Call(uintptr(hwnd), uintptr(unsafe.Pointer(&r)))
@@ -767,7 +791,10 @@ func SetWindowPos(hwnd syscall.Handle, hwndInsertAfter uint32, x, y, dx, dy int3
 }
 
 func SetWindowText(hwnd syscall.Handle, title string) {
-	wname := syscall.StringToUTF16Ptr(title)
+	wname, err := syscall.UTF16PtrFromString(title)
+	if err != nil {
+		panic(err)
+	}
 	_SetWindowText.Call(uintptr(hwnd), uintptr(unsafe.Pointer(wname)))
 }
 
@@ -883,6 +910,14 @@ func ReleaseDC(hdc syscall.Handle) {
 	_ReleaseDC.Call(uintptr(hdc))
 }
 
+func SendMessage(hwnd syscall.Handle, msg uint32, wParam, lParam uintptr) error {
+	r, _, err := _SendMessage.Call(uintptr(hwnd), uintptr(msg), wParam, lParam)
+	if r == 0 {
+		return fmt.Errorf("SendMessage failed: %v", err)
+	}
+	return nil
+}
+
 func SetForegroundWindow(hwnd syscall.Handle) {
 	_SetForegroundWindow.Call(uintptr(hwnd))
 }