Improve paste example

examples/paste/main.go

@@ -11,6 +11,8 @@ import "github.com/jezek/xgbutil/xprop"
 import "github.com/jezek/xgbutil/xevent"
 import "github.com/jezek/xgbutil/xwindow"
 
+// requestor implements xgbsel.Requestor. It asks for text and outputs it to
+// os.Stdout, and any logs to the default logging output (os.Stderr).
 type requestor struct {
 	window *xwindow.Window
 }
@@ -22,24 +24,42 @@ func (requestor requestor) Window () *xwindow.Window {
 func (requestor requestor) Success (target xgbsel.Target, data io.ReadCloser) {
 	defer data.Close()
 	text, _ := io.ReadAll(data)
-	log.Println("Clipboard text:", string(text))
+	log.Println("got clipboard text:")
+	os.Stdout.Write(text)
 	os.Exit(0)
 }
 
 func (requestor requestor) Failure (err error) {
+	if err == nil {
+		log.Fatalln("no available clipboard data")
+	} else {
 		log.Fatalln("could not get clipboard:", err)
+	}
 	os.Exit(1)
 }
 
-func (requestor requestor) Choose (from []xgbsel.Target) (xgbsel.Target, bool) {
-	for _, target := range from {
-		if target == "TEXT" {
-			return target, true
+func (requestor requestor) Choose (available []xgbsel.Target) (xgbsel.Target, bool) {
+	log.Println("owner supports these targets:", available)
+
+	// try to find the closest thing to text/plain by converting each target
+	// to a MIME type and comparing confidence values
+	var bestTarget     xgbsel.Target
+	var bestConfidence xgbsel.Confidence
+	for _, target := range available {
+		mime, confidence := target.ToMime()
+		if mime == "text/plain" && confidence > bestConfidence {
+			bestConfidence = confidence
+			bestTarget     = target
 		}
 	}
 
+	// if we have any confidence at all, return the result we got
+	if bestConfidence > xgbsel.ConfidenceNone {
+		return bestTarget, true
+	} else {
 		return "", false
 	}
+}
 
 func main () {
 	X, err := xgbutil.NewConn()