Add copy example

examples/copy/main.go

@@ -0,0 +1,73 @@
+// Example copy shows how to place text data in the CLIPBOARD selection.
+package main
+
+import "os"
+import "io"
+import "log"
+import "bytes"
+import "github.com/jezek/xgbutil"
+import "github.com/jezek/xgb/xproto"
+import "git.tebibyte.media/tomo/xgbsel"
+import "github.com/jezek/xgbutil/xprop"
+import "github.com/jezek/xgbutil/xevent"
+import "github.com/jezek/xgbutil/xwindow"
+
+// data is a very basic implementation of xgbsel.Data that only serves data of
+// one type.
+type data struct {
+	buffer io.ReadSeekCloser
+	mime   string
+}
+
+func (this *data) Convert (target xgbsel.Target) (io.ReadSeekCloser, bool) {
+	if mime, _ := target.ToMime(); mime == this.mime {
+		return this.buffer, true
+	} else {
+		return nil, false
+	}
+}
+
+func (this *data) Supported () []xgbsel.Target {
+	return xgbsel.MimeToTargets(this.mime)
+}
+
+// nopSeekCloser is like io.NopCloser but for an io.ReadSeeker.
+type nopSeekCloser struct { io.ReadSeeker }
+func (nopSeekCloser) Close () error { return nil }
+
+func main () {
+	// get data from user
+	log.Println("enter data, ^D when done: ")
+	buffer, _ := io.ReadAll(os.Stdin)
+	data := &data {
+		buffer: nopSeekCloser {
+			ReadSeeker: bytes.NewReader(buffer),
+		},
+		mime: "text/plain",
+	}
+
+	// establish connection
+	X, err := xgbutil.NewConn()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// create window
+	window, err := xwindow.Generate(X)
+	if err != nil {
+		log.Fatalln("could not generate a new window X id:", err)
+	}
+	window.Create(X.RootWin(), 0, 0, 500, 500, xproto.CwBackPixel, 0xffffffff)
+
+	// obtain claim on CLIPBOARD
+	log.Println("obtaining claim")
+	clipboard, _ := xprop.Atm(X, "CLIPBOARD")
+	claim := xgbsel.NewClaim(window, clipboard, data)
+
+	// listen for events
+	window.Listen(xproto.EventMaskPropertyChange)
+	xevent.SelectionRequestFun(claim.HandleSelectionRequest).Connect(X, window.Id)
+	
+	log.Println("running main event loop")
+	xevent.Main(X)
+}

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
 }
@@ -22,23 +24,41 @@ 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) {
-	log.Fatalln("could not get clipboard:", err)
+	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
 		}
 	}
 
-	return "", false
+	// if we have any confidence at all, return the result we got
+	if bestConfidence > xgbsel.ConfidenceNone {
+		return bestTarget, true
+	} else {
+		return "", false
+	}
 }
 
 func main () {