+++ /dev/null
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package x11 implements an X11 backend for the exp/gui package.
-//
-// The X protocol specification is at ftp://ftp.x.org/pub/X11R7.0/doc/PDF/proto.pdf.
-// A summary of the wire format can be found in XCB's xproto.xml.
-package x11
-
-import (
- "bufio"
- "errors"
- "exp/gui"
- "image"
- "image/draw"
- "io"
- "log"
- "net"
- "os"
- "strconv"
- "strings"
- "time"
-)
-
-type resID uint32 // X resource IDs.
-
-// TODO(nigeltao): Handle window resizes.
-const (
- windowHeight = 600
- windowWidth = 800
-)
-
-const (
- keymapLo = 8
- keymapHi = 255
-)
-
-type conn struct {
- c io.Closer
- r *bufio.Reader
- w *bufio.Writer
-
- gc, window, root, visual resID
-
- img *image.RGBA
- eventc chan interface{}
- mouseState gui.MouseEvent
-
- buf [256]byte // General purpose scratch buffer.
-
- flush chan bool
- flushBuf0 [24]byte
- flushBuf1 [4 * 1024]byte
-}
-
-// writeSocket runs in its own goroutine, serving both FlushImage calls
-// directly from the exp/gui client and indirectly from X expose events.
-// It paints c.img to the X server via PutImage requests.
-func (c *conn) writeSocket() {
- defer c.c.Close()
- for _ = range c.flush {
- b := c.img.Bounds()
- if b.Empty() {
- continue
- }
- // Each X request has a 16-bit length (in terms of 4-byte units). To avoid going over
- // this limit, we send PutImage for each row of the image, rather than trying to paint
- // the entire image in one X request. This approach could easily be optimized (or the
- // X protocol may have an escape sequence to delimit very large requests).
- // TODO(nigeltao): See what XCB's xcb_put_image does in this situation.
- units := 6 + b.Dx()
- if units > 0xffff || b.Dy() > 0xffff {
- log.Print("x11: window is too large for PutImage")
- return
- }
-
- c.flushBuf0[0] = 0x48 // PutImage opcode.
- c.flushBuf0[1] = 0x02 // XCB_IMAGE_FORMAT_Z_PIXMAP.
- c.flushBuf0[2] = uint8(units)
- c.flushBuf0[3] = uint8(units >> 8)
- setU32LE(c.flushBuf0[4:8], uint32(c.window))
- setU32LE(c.flushBuf0[8:12], uint32(c.gc))
- setU32LE(c.flushBuf0[12:16], 1<<16|uint32(b.Dx()))
- c.flushBuf0[21] = 0x18 // depth = 24 bits.
-
- for y := b.Min.Y; y < b.Max.Y; y++ {
- setU32LE(c.flushBuf0[16:20], uint32(y<<16))
- if _, err := c.w.Write(c.flushBuf0[:24]); err != nil {
- if err != io.EOF {
- log.Println("x11:", err)
- }
- return
- }
- p := c.img.Pix[(y-b.Min.Y)*c.img.Stride:]
- for x, dx := 0, 4*b.Dx(); x < dx; {
- nx := dx - x
- if nx > len(c.flushBuf1) {
- nx = len(c.flushBuf1) &^ 3
- }
- for i := 0; i < nx; i += 4 {
- // X11's order is BGRX, not RGBA.
- c.flushBuf1[i+0] = p[x+i+2]
- c.flushBuf1[i+1] = p[x+i+1]
- c.flushBuf1[i+2] = p[x+i+0]
- }
- x += nx
- if _, err := c.w.Write(c.flushBuf1[:nx]); err != nil {
- if err != io.EOF {
- log.Println("x11:", err)
- }
- return
- }
- }
- }
- if err := c.w.Flush(); err != nil {
- if err != io.EOF {
- log.Println("x11:", err)
- }
- return
- }
- }
-}
-
-func (c *conn) Screen() draw.Image { return c.img }
-
-func (c *conn) FlushImage() {
- select {
- case c.flush <- false:
- // Flush notification sent.
- default:
- // Could not send.
- // Flush notification must be pending already.
- }
-}
-
-func (c *conn) Close() error {
- // Shut down the writeSocket goroutine. This will close the socket to the
- // X11 server, which will cause c.eventc to close.
- close(c.flush)
- for _ = range c.eventc {
- // Drain the channel to allow the readSocket goroutine to shut down.
- }
- return nil
-}
-
-func (c *conn) EventChan() <-chan interface{} { return c.eventc }
-
-// readSocket runs in its own goroutine, reading X events and sending gui
-// events on c's EventChan.
-func (c *conn) readSocket() {
- var (
- keymap [256][]int
- keysymsPerKeycode int
- )
- defer close(c.eventc)
- for {
- // X events are always 32 bytes long.
- if _, err := io.ReadFull(c.r, c.buf[:32]); err != nil {
- if err != io.EOF {
- c.eventc <- gui.ErrEvent{err}
- }
- return
- }
- switch c.buf[0] {
- case 0x01: // Reply from a request (e.g. GetKeyboardMapping).
- cookie := int(c.buf[3])<<8 | int(c.buf[2])
- if cookie != 1 {
- // We issued only one request (GetKeyboardMapping) with a cookie of 1,
- // so we shouldn't get any other reply from the X server.
- c.eventc <- gui.ErrEvent{errors.New("x11: unexpected cookie")}
- return
- }
- keysymsPerKeycode = int(c.buf[1])
- b := make([]int, 256*keysymsPerKeycode)
- for i := range keymap {
- keymap[i] = b[i*keysymsPerKeycode : (i+1)*keysymsPerKeycode]
- }
- for i := keymapLo; i <= keymapHi; i++ {
- m := keymap[i]
- for j := range m {
- u, err := readU32LE(c.r, c.buf[:4])
- if err != nil {
- if err != io.EOF {
- c.eventc <- gui.ErrEvent{err}
- }
- return
- }
- m[j] = int(u)
- }
- }
- case 0x02, 0x03: // Key press, key release.
- // X Keyboard Encoding is documented at http://tronche.com/gui/x/xlib/input/keyboard-encoding.html
- // TODO(nigeltao): Do we need to implement the "MODE SWITCH / group modifier" feature
- // or is that some no-longer-used X construct?
- if keysymsPerKeycode < 2 {
- // Either we haven't yet received the GetKeyboardMapping reply or
- // the X server has sent one that's too short.
- continue
- }
- keycode := int(c.buf[1])
- shift := int(c.buf[28]) & 0x01
- keysym := keymap[keycode][shift]
- if keysym == 0 {
- keysym = keymap[keycode][0]
- }
- // TODO(nigeltao): Should we send KeyEvents for Shift/Ctrl/Alt? Should Shift-A send
- // the same int down the channel as the sent on just the A key?
- // TODO(nigeltao): How should IME events (e.g. key presses that should generate CJK text) work? Or
- // is that outside the scope of the gui.Window interface?
- if c.buf[0] == 0x03 {
- keysym = -keysym
- }
- c.eventc <- gui.KeyEvent{keysym}
- case 0x04, 0x05: // Button press, button release.
- mask := 1 << (c.buf[1] - 1)
- if c.buf[0] == 0x04 {
- c.mouseState.Buttons |= mask
- } else {
- c.mouseState.Buttons &^= mask
- }
- c.mouseState.Nsec = time.Nanoseconds()
- c.eventc <- c.mouseState
- case 0x06: // Motion notify.
- c.mouseState.Loc.X = int(int16(c.buf[25])<<8 | int16(c.buf[24]))
- c.mouseState.Loc.Y = int(int16(c.buf[27])<<8 | int16(c.buf[26]))
- c.mouseState.Nsec = time.Nanoseconds()
- c.eventc <- c.mouseState
- case 0x0c: // Expose.
- // A single user action could trigger multiple expose events (e.g. if moving another
- // window with XShape'd rounded corners over our window). In that case, the X server will
- // send a uint16 count (in bytes 16-17) of the number of additional expose events coming.
- // We could parse each event for the (x, y, width, height) and maintain a minimal dirty
- // rectangle, but for now, the simplest approach is to paint the entire window, when
- // receiving the final event in the series.
- if c.buf[17] == 0 && c.buf[16] == 0 {
- // TODO(nigeltao): Should we ignore the very first expose event? A freshly mapped window
- // will trigger expose, but until the first c.FlushImage call, there's probably nothing to
- // paint but black. For an 800x600 window, at 4 bytes per pixel, each repaint writes about
- // 2MB over the socket.
- c.FlushImage()
- }
- // TODO(nigeltao): Should we listen to DestroyNotify (0x11) and ResizeRequest (0x19) events?
- // What about EnterNotify (0x07) and LeaveNotify (0x08)?
- }
- }
-}
-
-// connect connects to the X server given by the full X11 display name (e.g.
-// ":12.0") and returns the connection as well as the portion of the full name
-// that is the display number (e.g. "12").
-// Examples:
-// connect(":1") // calls net.Dial("unix", "", "/tmp/.X11-unix/X1"), displayStr="1"
-// connect("/tmp/launch-123/:0") // calls net.Dial("unix", "", "/tmp/launch-123/:0"), displayStr="0"
-// connect("hostname:2.1") // calls net.Dial("tcp", "", "hostname:6002"), displayStr="2"
-// connect("tcp/hostname:1.0") // calls net.Dial("tcp", "", "hostname:6001"), displayStr="1"
-func connect(display string) (conn net.Conn, displayStr string, err error) {
- colonIdx := strings.LastIndex(display, ":")
- if colonIdx < 0 {
- return nil, "", errors.New("bad display: " + display)
- }
- // Parse the section before the colon.
- var protocol, host, socket string
- if display[0] == '/' {
- socket = display[:colonIdx]
- } else {
- if i := strings.LastIndex(display, "/"); i < 0 {
- // The default protocol is TCP.
- protocol = "tcp"
- host = display[:colonIdx]
- } else {
- protocol = display[:i]
- host = display[i+1 : colonIdx]
- }
- }
- // Parse the section after the colon.
- after := display[colonIdx+1:]
- if after == "" {
- return nil, "", errors.New("bad display: " + display)
- }
- if i := strings.LastIndex(after, "."); i < 0 {
- displayStr = after
- } else {
- displayStr = after[:i]
- }
- displayInt, err := strconv.Atoi(displayStr)
- if err != nil || displayInt < 0 {
- return nil, "", errors.New("bad display: " + display)
- }
- // Make the connection.
- if socket != "" {
- conn, err = net.Dial("unix", socket+":"+displayStr)
- } else if host != "" {
- conn, err = net.Dial(protocol, host+":"+strconv.Itoa(6000+displayInt))
- } else {
- conn, err = net.Dial("unix", "/tmp/.X11-unix/X"+displayStr)
- }
- if err != nil {
- return nil, "", errors.New("cannot connect to " + display + ": " + err.Error())
- }
- return
-}
-
-// authenticate authenticates ourselves with the X server.
-// displayStr is the "12" out of ":12.0".
-func authenticate(w *bufio.Writer, displayStr string) error {
- key, value, err := readAuth(displayStr)
- if err != nil {
- return err
- }
- // Assume that the authentication protocol is "MIT-MAGIC-COOKIE-1".
- if len(key) != 18 || len(value) != 16 {
- return errors.New("unsupported Xauth")
- }
- // 0x006c means little-endian. 0x000b, 0x0000 means X major version 11, minor version 0.
- // 0x0012 and 0x0010 means the auth key and value have lengths 18 and 16.
- // The final 0x0000 is padding, so that the string length is a multiple of 4.
- _, err = io.WriteString(w, "\x6c\x00\x0b\x00\x00\x00\x12\x00\x10\x00\x00\x00")
- if err != nil {
- return err
- }
- _, err = io.WriteString(w, key)
- if err != nil {
- return err
- }
- // Again, the 0x0000 is padding.
- _, err = io.WriteString(w, "\x00\x00")
- if err != nil {
- return err
- }
- _, err = io.WriteString(w, value)
- if err != nil {
- return err
- }
- err = w.Flush()
- if err != nil {
- return err
- }
- return nil
-}
-
-// readU8 reads a uint8 from r, using b as a scratch buffer.
-func readU8(r io.Reader, b []byte) (uint8, error) {
- _, err := io.ReadFull(r, b[:1])
- if err != nil {
- return 0, err
- }
- return uint8(b[0]), nil
-}
-
-// readU16LE reads a little-endian uint16 from r, using b as a scratch buffer.
-func readU16LE(r io.Reader, b []byte) (uint16, error) {
- _, err := io.ReadFull(r, b[:2])
- if err != nil {
- return 0, err
- }
- return uint16(b[0]) | uint16(b[1])<<8, nil
-}
-
-// readU32LE reads a little-endian uint32 from r, using b as a scratch buffer.
-func readU32LE(r io.Reader, b []byte) (uint32, error) {
- _, err := io.ReadFull(r, b[:4])
- if err != nil {
- return 0, err
- }
- return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24, nil
-}
-
-// setU32LE sets b[:4] to be the little-endian representation of u.
-func setU32LE(b []byte, u uint32) {
- b[0] = byte((u >> 0) & 0xff)
- b[1] = byte((u >> 8) & 0xff)
- b[2] = byte((u >> 16) & 0xff)
- b[3] = byte((u >> 24) & 0xff)
-}
-
-// checkPixmapFormats checks that we have an agreeable X pixmap Format.
-func checkPixmapFormats(r io.Reader, b []byte, n int) (agree bool, err error) {
- for i := 0; i < n; i++ {
- _, err = io.ReadFull(r, b[:8])
- if err != nil {
- return
- }
- // Byte 0 is depth, byte 1 is bits-per-pixel, byte 2 is scanline-pad, the rest (5) is padding.
- if b[0] == 24 && b[1] == 32 {
- agree = true
- }
- }
- return
-}
-
-// checkDepths checks that we have an agreeable X Depth (i.e. one that has an agreeable X VisualType).
-func checkDepths(r io.Reader, b []byte, n int, visual uint32) (agree bool, err error) {
- for i := 0; i < n; i++ {
- var depth, visualsLen uint16
- depth, err = readU16LE(r, b)
- if err != nil {
- return
- }
- depth &= 0xff
- visualsLen, err = readU16LE(r, b)
- if err != nil {
- return
- }
- // Ignore 4 bytes of padding.
- _, err = io.ReadFull(r, b[:4])
- if err != nil {
- return
- }
- for j := 0; j < int(visualsLen); j++ {
- // Read 24 bytes: visual(4), class(1), bits per rgb value(1), colormap entries(2),
- // red mask(4), green mask(4), blue mask(4), padding(4).
- v, _ := readU32LE(r, b)
- _, _ = readU32LE(r, b)
- rm, _ := readU32LE(r, b)
- gm, _ := readU32LE(r, b)
- bm, _ := readU32LE(r, b)
- _, err = readU32LE(r, b)
- if err != nil {
- return
- }
- if v == visual && rm == 0xff0000 && gm == 0xff00 && bm == 0xff && depth == 24 {
- agree = true
- }
- }
- }
- return
-}
-
-// checkScreens checks that we have an agreeable X Screen.
-func checkScreens(r io.Reader, b []byte, n int) (root, visual uint32, err error) {
- for i := 0; i < n; i++ {
- var root0, visual0, x uint32
- root0, err = readU32LE(r, b)
- if err != nil {
- return
- }
- // Ignore the next 7x4 bytes, which is: colormap, whitepixel, blackpixel, current input masks,
- // width and height (pixels), width and height (mm), min and max installed maps.
- _, err = io.ReadFull(r, b[:28])
- if err != nil {
- return
- }
- visual0, err = readU32LE(r, b)
- if err != nil {
- return
- }
- // Next 4 bytes: backing stores, save unders, root depth, allowed depths length.
- x, err = readU32LE(r, b)
- if err != nil {
- return
- }
- nDepths := int(x >> 24)
- var agree bool
- agree, err = checkDepths(r, b, nDepths, visual0)
- if err != nil {
- return
- }
- if agree && root == 0 {
- root = root0
- visual = visual0
- }
- }
- return
-}
-
-// handshake performs the protocol handshake with the X server, and ensures
-// that the server provides a compatible Screen, Depth, etc.
-func (c *conn) handshake() error {
- _, err := io.ReadFull(c.r, c.buf[:8])
- if err != nil {
- return err
- }
- // Byte 0 should be 1 (success), bytes 2:6 should be 0xb0000000 (major/minor version 11.0).
- if c.buf[0] != 1 || c.buf[2] != 11 || c.buf[3] != 0 || c.buf[4] != 0 || c.buf[5] != 0 {
- return errors.New("unsupported X version")
- }
- // Ignore the release number.
- _, err = io.ReadFull(c.r, c.buf[:4])
- if err != nil {
- return err
- }
- // Read the resource ID base.
- resourceIdBase, err := readU32LE(c.r, c.buf[:4])
- if err != nil {
- return err
- }
- // Read the resource ID mask.
- resourceIdMask, err := readU32LE(c.r, c.buf[:4])
- if err != nil {
- return err
- }
- if resourceIdMask < 256 {
- return errors.New("X resource ID mask is too small")
- }
- // Ignore the motion buffer size.
- _, err = io.ReadFull(c.r, c.buf[:4])
- if err != nil {
- return err
- }
- // Read the vendor length and round it up to a multiple of 4,
- // for X11 protocol alignment reasons.
- vendorLen, err := readU16LE(c.r, c.buf[:2])
- if err != nil {
- return err
- }
- vendorLen = (vendorLen + 3) &^ 3
- // Read the maximum request length.
- maxReqLen, err := readU16LE(c.r, c.buf[:2])
- if err != nil {
- return err
- }
- if maxReqLen != 0xffff {
- return errors.New("unsupported X maximum request length")
- }
- // Read the roots length.
- rootsLen, err := readU8(c.r, c.buf[:1])
- if err != nil {
- return err
- }
- // Read the pixmap formats length.
- pixmapFormatsLen, err := readU8(c.r, c.buf[:1])
- if err != nil {
- return err
- }
- // Ignore some things that we don't care about (totaling 10 + vendorLen bytes):
- // imageByteOrder(1), bitmapFormatBitOrder(1), bitmapFormatScanlineUnit(1) bitmapFormatScanlinePad(1),
- // minKeycode(1), maxKeycode(1), padding(4), vendor (vendorLen).
- if 10+int(vendorLen) > cap(c.buf) {
- return errors.New("unsupported X vendor")
- }
- _, err = io.ReadFull(c.r, c.buf[:10+int(vendorLen)])
- if err != nil {
- return err
- }
- // Check that we have an agreeable pixmap format.
- agree, err := checkPixmapFormats(c.r, c.buf[:8], int(pixmapFormatsLen))
- if err != nil {
- return err
- }
- if !agree {
- return errors.New("unsupported X pixmap formats")
- }
- // Check that we have an agreeable screen.
- root, visual, err := checkScreens(c.r, c.buf[:24], int(rootsLen))
- if err != nil {
- return err
- }
- if root == 0 || visual == 0 {
- return errors.New("unsupported X screen")
- }
- c.gc = resID(resourceIdBase)
- c.window = resID(resourceIdBase + 1)
- c.root = resID(root)
- c.visual = resID(visual)
- return nil
-}
-
-// NewWindow calls NewWindowDisplay with $DISPLAY.
-func NewWindow() (gui.Window, error) {
- display := os.Getenv("DISPLAY")
- if len(display) == 0 {
- return nil, errors.New("$DISPLAY not set")
- }
- return NewWindowDisplay(display)
-}
-
-// NewWindowDisplay returns a new gui.Window, backed by a newly created and
-// mapped X11 window. The X server to connect to is specified by the display
-// string, such as ":1".
-func NewWindowDisplay(display string) (gui.Window, error) {
- socket, displayStr, err := connect(display)
- if err != nil {
- return nil, err
- }
- c := new(conn)
- c.c = socket
- c.r = bufio.NewReader(socket)
- c.w = bufio.NewWriter(socket)
- err = authenticate(c.w, displayStr)
- if err != nil {
- return nil, err
- }
- err = c.handshake()
- if err != nil {
- return nil, err
- }
-
- // Now that we're connected, show a window, via three X protocol messages.
- // First, issue a GetKeyboardMapping request. This is the first request, and
- // will be associated with a cookie of 1.
- setU32LE(c.buf[0:4], 0x00020065) // 0x65 is the GetKeyboardMapping opcode, and the message is 2 x 4 bytes long.
- setU32LE(c.buf[4:8], uint32((keymapHi-keymapLo+1)<<8|keymapLo))
- // Second, create a graphics context (GC).
- setU32LE(c.buf[8:12], 0x00060037) // 0x37 is the CreateGC opcode, and the message is 6 x 4 bytes long.
- setU32LE(c.buf[12:16], uint32(c.gc))
- setU32LE(c.buf[16:20], uint32(c.root))
- setU32LE(c.buf[20:24], 0x00010004) // Bit 2 is XCB_GC_FOREGROUND, bit 16 is XCB_GC_GRAPHICS_EXPOSURES.
- setU32LE(c.buf[24:28], 0x00000000) // The Foreground is black.
- setU32LE(c.buf[28:32], 0x00000000) // GraphicsExposures' value is unused.
- // Third, create the window.
- setU32LE(c.buf[32:36], 0x000a0001) // 0x01 is the CreateWindow opcode, and the message is 10 x 4 bytes long.
- setU32LE(c.buf[36:40], uint32(c.window))
- setU32LE(c.buf[40:44], uint32(c.root))
- setU32LE(c.buf[44:48], 0x00000000) // Initial (x, y) is (0, 0).
- setU32LE(c.buf[48:52], windowHeight<<16|windowWidth)
- setU32LE(c.buf[52:56], 0x00010000) // Border width is 0, XCB_WINDOW_CLASS_INPUT_OUTPUT is 1.
- setU32LE(c.buf[56:60], uint32(c.visual))
- setU32LE(c.buf[60:64], 0x00000802) // Bit 1 is XCB_CW_BACK_PIXEL, bit 11 is XCB_CW_EVENT_MASK.
- setU32LE(c.buf[64:68], 0x00000000) // The Back-Pixel is black.
- setU32LE(c.buf[68:72], 0x0000804f) // Key/button press and release, pointer motion, and expose event masks.
- // Fourth, map the window.
- setU32LE(c.buf[72:76], 0x00020008) // 0x08 is the MapWindow opcode, and the message is 2 x 4 bytes long.
- setU32LE(c.buf[76:80], uint32(c.window))
- // Write the bytes.
- _, err = c.w.Write(c.buf[:80])
- if err != nil {
- return nil, err
- }
- err = c.w.Flush()
- if err != nil {
- return nil, err
- }
-
- c.img = image.NewRGBA(image.Rect(0, 0, windowWidth, windowHeight))
- c.eventc = make(chan interface{}, 16)
- c.flush = make(chan bool, 1)
- go c.readSocket()
- go c.writeSocket()
- return c, nil
-}