add: linux implementation

.github/workflows/test.yaml

@@ -13,12 +13,11 @@ jobs:
     steps:
       - name: Checkout code
         uses: actions/checkout@master
-      - name: Setup X server on ubuntu-latest
+      - name: Setup X on Linux
         if: runner.os == 'Linux'
         run: |
           sudo apt update -y
-          sudo apt install -y xorg openbox
-          sudo startx
+          sudo apt install xvfb
       - name: Setup Go
         uses: actions/setup-go@v1
         with:

README.md

@@ -15,9 +15,6 @@ This is a multi-platform clipboard library in Go.
 
 - Windows
 - macOS
-
-### ⚠WIP⚠
-
 - Linux, Unix (X11)
 
 ## Installation

clipboard_test.go

@@ -21,7 +21,7 @@ func TestCopyAndPaste(t *testing.T) {
 				t.Error(err)
 			}
 			if got != tt.want {
-				t.Errorf("CopyAndPaste mismatch: got %v, want %v", got, tt.want)
+				t.Errorf("copy and paste mismatch: got %v, want %v", got, tt.want)
 			}
 		})
 	}

clipboard_unix.go

@@ -0,0 +1,230 @@
+// The MIT License (MIT)
+// Copyright (c) 2016 Alessandro Arzilli
+// https://github.com/aarzilli/nucular/blob/master/LICENSE
+
+// +build freebsd linux netbsd openbsd solaris dragonfly
+
+package clipboard
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/BurntSushi/xgb"
+	"github.com/BurntSushi/xgb/xproto"
+	"golang.org/x/xerrors"
+)
+
+const debugClipboardRequests = false
+
+var (
+	X             *xgb.Conn
+	win           xproto.Window
+	clipboardText string
+	selnotify     chan bool
+
+	clipboardAtom, primaryAtom, textAtom, targetsAtom, atomAtom xproto.Atom
+	targetAtoms                                                 []xproto.Atom
+	clipboardAtomCache                                          = map[xproto.Atom]string{}
+
+	doneCh = make(chan interface{}, 1)
+)
+
+func start() error {
+	var err error
+	xServer := os.Getenv("DISPLAY")
+	if xServer == "" {
+		return xerrors.New("could not identify xserver")
+	}
+	X, err = xgb.NewConnDisplay(xServer)
+	if err != nil {
+		return xerrors.Errorf("%w", err)
+	}
+
+	selnotify = make(chan bool, 1)
+
+	win, err = xproto.NewWindowId(X)
+	if err != nil {
+		return xerrors.Errorf("%w", err)
+	}
+
+	setup := xproto.Setup(X)
+	s := setup.DefaultScreen(X)
+	err = xproto.CreateWindowChecked(X, s.RootDepth, win, s.Root, 100, 100, 1, 1, 0, xproto.WindowClassInputOutput, s.RootVisual, 0, []uint32{}).Check()
+	if err != nil {
+		return xerrors.Errorf("%w", err)
+	}
+
+	clipboardAtom = internAtom(X, "CLIPBOARD")
+	primaryAtom = internAtom(X, "PRIMARY")
+	textAtom = internAtom(X, "UTF8_STRING")
+	targetsAtom = internAtom(X, "TARGETS")
+	atomAtom = internAtom(X, "ATOM")
+
+	targetAtoms = []xproto.Atom{targetsAtom, textAtom}
+
+	go eventLoop()
+
+	return nil
+}
+
+func set(text string) error {
+	if err := start(); err != nil {
+		return xerrors.Errorf("init clipboard: %w", err)
+	}
+	clipboardText = text
+	ssoc := xproto.SetSelectionOwnerChecked(X, win, clipboardAtom, xproto.TimeCurrentTime)
+	if err := ssoc.Check(); err != nil {
+		return xerrors.Errorf("setting clipboard: %w", err)
+	}
+	return nil
+}
+
+func get() (string, error) {
+	if err := start(); err != nil {
+		return "", xerrors.Errorf("init clipboard: %w", err)
+	}
+	return getSelection(clipboardAtom)
+}
+
+func getSelection(selAtom xproto.Atom) (string, error) {
+	csc := xproto.ConvertSelectionChecked(X, win, selAtom, textAtom, selAtom, xproto.TimeCurrentTime)
+	err := csc.Check()
+	if err != nil {
+		return "", xerrors.Errorf("convert selection check: %w", err)
+	}
+
+	select {
+	case r := <-selnotify:
+		if !r {
+			return "", nil
+		}
+		gpc := xproto.GetProperty(X, true, win, selAtom, textAtom, 0, 5*1024*1024)
+		gpr, err := gpc.Reply()
+		if err != nil {
+			return "", xerrors.Errorf("grp reply: %w", err)
+		}
+		if gpr.BytesAfter != 0 {
+			return "", xerrors.New("clipboard too large")
+		}
+		return string(gpr.Value[:gpr.ValueLen]), nil
+	case <-time.After(1 * time.Second):
+		return "", xerrors.New("clipboard retrieval failed, timeout")
+	}
+}
+
+func pollForEvent(X *xgb.Conn, events chan<- xgb.Event) {
+	for {
+		select {
+		case <-doneCh:
+			return
+		default:
+			ev, err := X.PollForEvent()
+			if err != nil {
+				fmt.Println("wait for event:", err)
+			}
+			events <- ev
+		}
+	}
+}
+
+func eventLoop() {
+	eventCh := make(chan xgb.Event, 1)
+	go pollForEvent(X, eventCh)
+	for {
+		select {
+		case event := <-eventCh:
+			switch e := event.(type) {
+			case xproto.SelectionRequestEvent:
+				if debugClipboardRequests {
+					tgtname := lookupAtom(e.Target)
+					propname := lookupAtom(e.Property)
+					fmt.Println("SelectionRequest", e, textAtom, tgtname, propname, "isPrimary:", e.Selection == primaryAtom, "isClipboard:", e.Selection == clipboardAtom)
+				}
+				t := clipboardText
+
+				switch e.Target {
+				case textAtom:
+					if debugClipboardRequests {
+						fmt.Println("Sending as text")
+					}
+					cpc := xproto.ChangePropertyChecked(X, xproto.PropModeReplace, e.Requestor, e.Property, textAtom, 8, uint32(len(t)), []byte(t))
+					err := cpc.Check()
+					if err == nil {
+						sendSelectionNotify(e)
+					} else {
+						fmt.Println(err)
+					}
+
+				case targetsAtom:
+					if debugClipboardRequests {
+						fmt.Println("Sending targets")
+					}
+					buf := make([]byte, len(targetAtoms)*4)
+					for i, atom := range targetAtoms {
+						xgb.Put32(buf[i*4:], uint32(atom))
+					}
+
+					err := xproto.ChangePropertyChecked(X, xproto.PropModeReplace, e.Requestor, e.Property, atomAtom, 32, uint32(len(targetAtoms)), buf).Check()
+					if err == nil {
+						sendSelectionNotify(e)
+					} else {
+						fmt.Println(err)
+					}
+
+				default:
+					if debugClipboardRequests {
+						fmt.Println("Skipping")
+					}
+					e.Property = 0
+					sendSelectionNotify(e)
+				}
+
+			case xproto.SelectionNotifyEvent:
+				selnotify <- (e.Property == clipboardAtom) || (e.Property == primaryAtom)
+			}
+		case <-doneCh:
+			return
+		}
+	}
+}
+
+func lookupAtom(at xproto.Atom) string {
+	if s, ok := clipboardAtomCache[at]; ok {
+		return s
+	}
+
+	reply, err := xproto.GetAtomName(X, at).Reply()
+	if err != nil {
+		panic(err)
+	}
+
+	// If we're here, it means we didn't have ths ATOM id cached. So cache it.
+	atomName := string(reply.Name)
+	clipboardAtomCache[at] = atomName
+	return atomName
+}
+
+func sendSelectionNotify(e xproto.SelectionRequestEvent) {
+	sn := xproto.SelectionNotifyEvent{
+		Time:      e.Time,
+		Requestor: e.Requestor,
+		Selection: e.Selection,
+		Target:    e.Target,
+		Property:  e.Property}
+	sec := xproto.SendEventChecked(X, false, e.Requestor, 0, string(sn.Bytes()))
+	err := sec.Check()
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+
+func internAtom(conn *xgb.Conn, n string) xproto.Atom {
+	iac := xproto.InternAtom(conn, true, uint16(len(n)), n)
+	iar, err := iac.Reply()
+	if err != nil {
+		panic(err)
+	}
+	return iar.Atom
+}

go.mod

@@ -4,6 +4,7 @@ go 1.14
 
 require (
 	git.wow.st/gmp/clip v0.0.0-20191001134149-1458ba6a7cf5
+	github.com/BurntSushi/xgb v0.0.0-20200324125942-20f126ea2843
 	github.com/lxn/walk v0.0.0-20191128110447-55ccb3a9f5c1
 	github.com/lxn/win v0.0.0-20191128105842-2da648fda5b4 // indirect
 	golang.org/x/sys v0.0.0-20200509044756-6aff5f38e54f // indirect

go.sum

@@ -1,5 +1,7 @@
 git.wow.st/gmp/clip v0.0.0-20191001134149-1458ba6a7cf5 h1:OKeTjZST+/TKvtdA258NXJH+/gIx/xwyZxKrAezNFvk=
 git.wow.st/gmp/clip v0.0.0-20191001134149-1458ba6a7cf5/go.mod h1:NLdpaBoMQNFqncwP8OVRNWUDw1Kt9XWm3snfT7cXu24=
+github.com/BurntSushi/xgb v0.0.0-20200324125942-20f126ea2843 h1:3iF31c7rp7nGZVDv7YQ+VxOgpipVfPKotLXykjZmwM8=
+github.com/BurntSushi/xgb v0.0.0-20200324125942-20f126ea2843/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/lxn/walk v0.0.0-20191128110447-55ccb3a9f5c1 h1:/QwQcwWVOQXcoNuV9tHx30gQ3q7jCE/rKcGjwzsa5tg=
 github.com/lxn/walk v0.0.0-20191128110447-55ccb3a9f5c1/go.mod h1:E23UucZGqpuUANJooIbHWCufXvOcT6E7Stq81gU+CSQ=
 github.com/lxn/win v0.0.0-20191128105842-2da648fda5b4 h1:5BmtGkQbch91lglMHQ9JIDGiYCL3kBRBA0ItZTvOcEI=