1 files changed, 161 insertions, 0 deletions
diff --git a/nexgb/conn.go b/nexgb/conn.go
new file mode 100644
index 0000000..235402d
--- /dev/null
+++ b/nexgb/conn.go
@@ -0,0 +1,161 @@
+package xgb
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// connect connects to the X server given in the 'display' string.
+// If 'display' is empty it will be taken from os.Getenv("DISPLAY").
+// Note that you should read and understand the "Connection Setup" of the
+// X Protocol Reference Manual before changing this function:
+// http://goo.gl/4zGQg
+func (c *Conn) connect(display string) error {
+	err := c.dial(display)
+	if err != nil {
+		return err
+	}
+
+	// Get authentication data
+	authName, authData, err := readAuthority(c.host, c.display)
+	noauth := false
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Could not get authority info: %v\n", err)
+		fmt.Fprintf(os.Stderr, "Trying connection without authority info...\n")
+		authName = ""
+		authData = []byte{}
+		noauth = true
+	}
+
+	// Assume that the authentication protocol is "MIT-MAGIC-COOKIE-1".
+	if !noauth && (authName != "MIT-MAGIC-COOKIE-1" || len(authData) != 16) {
+		return errors.New("unsupported auth protocol " + authName)
+	}
+
+	buf := make([]byte, 12+pad(len(authName))+pad(len(authData)))
+	buf[0] = 0x6c
+	buf[1] = 0
+	Put16(buf[2:], 11)
+	Put16(buf[4:], 0)
+	Put16(buf[6:], uint16(len(authName)))
+	Put16(buf[8:], uint16(len(authData)))
+	Put16(buf[10:], 0)
+	copy(buf[12:], []byte(authName))
+	copy(buf[12+pad(len(authName)):], authData)
+	if _, err = c.conn.Write(buf); err != nil {
+		return err
+	}
+
+	head := make([]byte, 8)
+	if _, err = io.ReadFull(c.conn, head[0:8]); err != nil {
+		return err
+	}
+	code := head[0]
+	reasonLen := head[1]
+	major := Get16(head[2:])
+	minor := Get16(head[4:])
+	dataLen := Get16(head[6:])
+
+	if major != 11 || minor != 0 {
+		return errors.New(fmt.Sprintf("x protocol version mismatch: %d.%d",
+			major, minor))
+	}
+
+	buf = make([]byte, int(dataLen)*4+8, int(dataLen)*4+8)
+	copy(buf, head)
+	if _, err = io.ReadFull(c.conn, buf[8:]); err != nil {
+		return err
+	}
+
+	if code == 0 {
+		reason := buf[8 : 8+reasonLen]
+		return errors.New(fmt.Sprintf("x protocol authentication refused: %s",
+			string(reason)))
+	}
+
+	ReadSetupInfo(buf, &c.Setup)
+
+	if c.defaultScreen >= len(c.Setup.Roots) {
+		c.defaultScreen = 0
+	}
+
+	return nil
+}
+
+func (c *Conn) dial(display string) error {
+	if len(display) == 0 {
+		display = os.Getenv("DISPLAY")
+	}
+
+	display0 := display
+	if len(display) == 0 {
+		return errors.New("empty display string")
+	}
+
+	colonIdx := strings.LastIndex(display, ":")
+	if colonIdx < 0 {
+		return errors.New("bad display string: " + display0)
+	}
+
+	var protocol, socket string
+
+	if display[0] == '/' {
+		socket = display[0:colonIdx]
+	} else {
+		slashIdx := strings.LastIndex(display, "/")
+		if slashIdx >= 0 {
+			protocol = display[0:slashIdx]
+			c.host = display[slashIdx+1 : colonIdx]
+		} else {
+			c.host = display[0:colonIdx]
+		}
+	}
+
+	display = display[colonIdx+1 : len(display)]
+	if len(display) == 0 {
+		return errors.New("bad display string: " + display0)
+	}
+
+	var scr string
+	dotIdx := strings.LastIndex(display, ".")
+	if dotIdx < 0 {
+		c.display = display[0:]
+	} else {
+		c.display = display[0:dotIdx]
+		scr = display[dotIdx+1:]
+	}
+
+	dispnum, err := strconv.Atoi(c.display)
+	if err != nil || dispnum < 0 {
+		return errors.New("bad display string: " + display0)
+	}
+
+	if len(scr) != 0 {
+		c.defaultScreen, err = strconv.Atoi(scr)
+		if err != nil {
+			return errors.New("bad display string: " + display0)
+		}
+	}
+
+	// Connect to server
+	if len(socket) != 0 {
+		c.conn, err = net.Dial("unix", socket+":"+c.display)
+	} else if len(c.host) != 0 {
+		if protocol == "" {
+			protocol = "tcp"
+		}
+		c.conn, err = net.Dial(protocol, c.host+":"+strconv.Itoa(6000+dispnum))
+	} else {
+		c.conn, err = net.Dial("unix", "/tmp/.X11-unix/X"+c.display)
+	}
+
+	if err != nil {
+		return errors.New("cannot connect to " + display0 + ": " + err.Error())
+	}
+	return nil
+}