fix: Windows writeAll error

lib/clipboard/clipboard_windows.go

@@ -7,126 +7,55 @@
 package clipboard
 
 import (
+	"errors"
 	"syscall"
-	"time"
 	"unsafe"
+
+	"github.com/lxn/win"
 )
 
-const (
-	cfUnicodetext = 13
-	// gmemFixed     = 0x0000
-	gmemMoveable = 0x0002
-)
-
-var (
-	user32           = syscall.MustLoadDLL("user32")
-	openClipboard    = user32.MustFindProc("OpenClipboard")
-	closeClipboard   = user32.MustFindProc("CloseClipboard")
-	emptyClipboard   = user32.MustFindProc("EmptyClipboard")
-	getClipboardData = user32.MustFindProc("GetClipboardData")
-	setClipboardData = user32.MustFindProc("SetClipboardData")
-
-	kernel32     = syscall.NewLazyDLL("kernel32")
-	globalAlloc  = kernel32.NewProc("GlobalAlloc")
-	globalFree   = kernel32.NewProc("GlobalFree")
-	globalLock   = kernel32.NewProc("GlobalLock")
-	globalUnlock = kernel32.NewProc("GlobalUnlock")
-	lstrcpy      = kernel32.NewProc("lstrcpyW")
-)
-
-// waitOpenClipboard opens the clipboard, waiting for up to a second to do so.
-func waitOpenClipboard() error {
-	started := time.Now()
-	limit := started.Add(time.Second)
-	var r uintptr
-	var err error
-	for time.Now().Before(limit) {
-		r, _, err = openClipboard.Call(0)
-		if r != 0 {
-			return nil
-		}
-		time.Sleep(time.Millisecond)
-	}
-	return err
-}
-
 func readAll() (string, error) {
-	// r, _, err := openClipboard.Call(0)
-	err := waitOpenClipboard()
-	if err != nil {
-		return "", err
+	if !win.OpenClipboard(0) {
+		return "", errors.New("OpenClipboard")
 	}
-	defer closeClipboard.Call()
-
-	h, _, err := getClipboardData.Call(cfUnicodetext)
-	if h == 0 {
-		return "", err
+	defer win.CloseClipboard()
+	hMem := win.HGLOBAL(win.GetClipboardData(win.CF_UNICODETEXT))
+	if hMem == 0 {
+		return "", errors.New("GetClipboardData")
 	}
-
-	l, _, err := globalLock.Call(h)
-	if l == 0 {
-		return "", err
+	p := win.GlobalLock(hMem)
+	if p == nil {
+		return "", errors.New("GlobalLock()")
 	}
-
-	text := syscall.UTF16ToString((*[1 << 20]uint16)(unsafe.Pointer(l))[:])
-
-	r, _, err := globalUnlock.Call(h)
-	if r == 0 {
-		return "", err
-	}
-
+	defer win.GlobalUnlock(hMem)
+	text := win.UTF16PtrToString((*uint16)(p))
 	return text, nil
 }
 
 func writeAll(text string) error {
-	err := waitOpenClipboard()
+	if !win.OpenClipboard(0) {
+		return errors.New("OpenClipboard")
+	}
+	defer win.CloseClipboard()
+	utf16, err := syscall.UTF16FromString(text)
 	if err != nil {
 		return err
 	}
-	defer closeClipboard.Call()
-
-	r, _, err := emptyClipboard.Call(0)
-	if r == 0 {
-		return err
+	hMem := win.GlobalAlloc(win.GMEM_MOVEABLE, uintptr(len(utf16)*2))
+	if hMem == 0 {
+		return errors.New("GlobalAlloc")
 	}
-
-	data := syscall.StringToUTF16(text)
-
-	// "If the hMem parameter identifies a memory object, the object must have
-	// been allocated using the function with the GMEM_MOVEABLE flag."
-	h, _, err := globalAlloc.Call(gmemMoveable,
-		uintptr(len(data)*int(unsafe.Sizeof(data[0]))))
-	if h == 0 {
-		return err
+	p := win.GlobalLock(hMem)
+	if p == nil {
+		return errors.New("GlobalLock()")
 	}
-	defer func() {
-		if h != 0 {
-			globalFree.Call(h)
-		}
-	}()
-
-	l, _, err := globalLock.Call(h)
-	if l == 0 {
-		return err
+	win.MoveMemory(p, unsafe.Pointer(&utf16[0]), uintptr(len(utf16)*2))
+	win.GlobalUnlock(hMem)
+	if 0 == win.SetClipboardData(win.CF_UNICODETEXT, win.HANDLE(hMem)) {
+		// We need to free hMem.
+		defer win.GlobalFree(hMem)
+		return errors.New("SetClipboardData")
 	}
-
-	r, _, err = lstrcpy.Call(l, uintptr(unsafe.Pointer(&data[0])))
-	if r == 0 {
-		return err
-	}
-
-	r, _, err = globalUnlock.Call(h)
-	if r == 0 {
-		return err
-	}
-
-	r, _, err = setClipboardData.Call(cfUnicodetext, h)
-	if r == 0 {
-		if err.(syscall.Errno) != 0 {
-			return err
-		}
-	}
-
-	h = 0 // suppress deferred cleanup
+	// The system now owns the memory referred to by hMem.
 	return nil
 }

main.go

@@ -27,22 +27,22 @@ func main() {
 }
 
 const (
-	TextHeader = "Go-Clipboard-Text"
-	TimeHeader = "Go-Clipboard-Time"
+	textHeader = "Go-Clipboard-Text"
+	timeHeader = "Go-Clipboard-Time"
 )
 
 func startServer(b string) {
 	text := ""
 	time := time.Now().Unix()
-	var err error
-	g := gin.Default()
+	g := gin.New()
 	g.GET("/", func(c *gin.Context) {
-		c.Header(TextHeader, text)
-		c.Header(TimeHeader, strconv.FormatInt(time, 10))
+		c.Header(textHeader, text)
+		c.Header(timeHeader, strconv.FormatInt(time, 10))
 	})
 	g.POST("/", func(c *gin.Context) {
 		text = c.Query("text")
-		time, err = strconv.ParseInt(c.Query("time"), 10, 64)
+		time, _ = strconv.ParseInt(c.Query("time"), 10, 64)
+		fmt.Printf("Update Clipboard: %s\n", text)
 	})
 	g.Run(b)
 }
@@ -63,11 +63,11 @@ func readClipboard(a string) {
 			client.Do(request)
 		} else {
 			response, _ := http.Get(a)
-			texts, ok := response.Header[TextHeader]
+			texts, ok := response.Header[textHeader]
 			if ok {
 				sText := texts[0]
-				sTime, _ := strconv.ParseInt(response.Header[TimeHeader][0], 10, 64)
-				if sTime > updateTime {
+				sTime, _ := strconv.ParseInt(response.Header[timeHeader][0], 10, 64)
+				if sTime > updateTime && sText != old {
 					old = sText
 					updateTime = time.Now().Unix()
 					clipboard.WriteAll(sText)