Use github.com/zyedidia/clipboard for clipboard.

Now one can choose as register clipboard and primary.

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/sasha-s/go-deadlock v0.2.0
 	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
 	github.com/stretchr/testify v1.5.1
+	github.com/zyedidia/clipboard v0.0.0-20190823154308-241f98e9b197
 	go.etcd.io/bbolt v1.3.3
 	golang.org/x/image v0.0.0-20200119044424-58c23975cae1
 	golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e

ui/commands.go

@@ -34,7 +34,6 @@ import (
 
 	"github.com/lucasb-eyer/go-colorful"
 	"github.com/russross/blackfriday/v2"
-	"github.com/atotto/clipboard"
 
 	"maunium.net/go/mautrix"
 	"maunium.net/go/mautrix/event"
@@ -179,10 +178,14 @@ func cmdOpen(cmd *Command) {
 }
 
 func cmdCopy(cmd *Command) {
-	if clipboard.Unsupported {
+	register := strings.Join(cmd.Args, " ")
-		cmd.Reply("Clipboard unsupported.")
+	if len(register) == 0 {
+		register = "clipboard"
+	}
+	if (register == "clipboard" || register == "primary") {
+		cmd.Room.StartSelecting(SelectCopy, register)
 	} else {
-		cmd.Room.StartSelecting(SelectCopy, strings.Join(cmd.Args, " "))
+		cmd.Reply("Usage: /copy [register], where register is either \"clipboard\" or \"primary\". Defaults to \"clipboard\".")
 	}
 }
 

ui/room-view.go

@@ -25,7 +25,7 @@ import (
 
 	"github.com/kyokomi/emoji"
 	"github.com/mattn/go-runewidth"
-	"github.com/atotto/clipboard"
+	"github.com/zyedidia/clipboard"
 
 	"maunium.net/go/mauview"
 	"maunium.net/go/tcell"
@@ -208,7 +208,7 @@ func (view *RoomView) OnSelect(message *messages.UIMessage) {
 	case SelectCopy:
 		msg, ok := message.Renderer.(*messages.TextMessage)
 		if ok {
-			go clipboard.WriteAll(msg.PlainText())
+			go view.CopyToClipboard(msg.PlainText(),view.selectContent)
 		}
 	}
 	view.selecting = false
@@ -630,6 +630,21 @@ func (view *RoomView) InputSubmit(text string) {
 	view.SetInputText("")
 }
 
+func (view *RoomView) CopyToClipboard(text string, register string) {
+	if (register == "clipboard" || register == "primary") {
+		err := clipboard.WriteAll(text,register)
+		if err != nil {
+			view.AddServiceMessage(fmt.Sprintf("Clipboard unsupported: %v", err))
+			view.parent.parent.Render()
+			return
+		}
+	} else {
+		view.AddServiceMessage(fmt.Sprintf("Clipboard register %v unsupported", register))
+		view.parent.parent.Render()
+		return
+	}
+}
+
 func (view *RoomView) Download(url id.ContentURI, filename string, openFile bool) {
 	path, err := view.parent.matrix.DownloadToDisk(url, filename)
 	if err != nil {