ReadXSettings.go

//this simple file show you how to read the XSettings properties (http://standards.freedesktop.org/xsettings-spec/xsettings-spec-0.5.html)
package main

import "fmt"
import "github.com/BurntSushi/xgb/xproto"
import "github.com/BurntSushi/xgb"
import "encoding/binary"
import "io"
import "bytes"

func getAtom(X *xgb.Conn, name string) xproto.Atom {
	reply, err := xproto.InternAtom(X, false, uint16(len(name)), name).Reply()
	if err != nil {
		panic("GetAtom " + name + " Failed")
	}
	return reply.Atom
}

func readString(buf io.Reader, order binary.ByteOrder) string {
	var nameLen uint32
	binary.Read(buf, order, &nameLen)
	if nameLen > 1000 {
		fmt.Println("nameLen Toolong", nameLen)
		return ""
	}

	nameBuf := make([]byte, nameLen)
	binary.Read(buf, order, &nameBuf)
        leftPad := 3 - (nameLen+3)%4
	buf.Read(make([]byte, leftPad))
	return string(nameBuf)
}
func readInterger(buf io.Reader, order binary.ByteOrder) uint32 {
	body := uint32(0)
	binary.Read(buf, order, &body)
	return body
}
func readColor(buf io.Reader, order binary.ByteOrder) (r uint16, g uint16, b uint16, a uint16) {
	binary.Read(buf, order, &r)
	binary.Read(buf, order, &g)
	binary.Read(buf, order, &b)
	binary.Read(buf, order, &a)
	return
}

func readString2(buf io.Reader, order binary.ByteOrder) string {
	var nameLen uint16
	binary.Read(buf, order, &nameLen)

	nameBuf := make([]byte, nameLen)
	binary.Read(buf, order, &nameBuf)
	leftPad := 3 - (nameLen+3)%4
	buf.Read(make([]byte, leftPad))
	return string(nameBuf)
}

func readHeader(buf io.Reader, order binary.ByteOrder) (byte, string, uint32) {
	var sType byte
	binary.Read(buf, order, &sType)
	buf.Read(make([]byte, 1))

	name := readString2(buf, order)
	lastSerial := readInterger(buf, order)

	return sType, name, lastSerial
}

func main() {
	X, _ := xgb.NewConn()
	s, _ := xproto.GetSelectionOwner(X, getAtom(X, "_XSETTINGS_S0")).Reply()

	reply, err := xproto.GetProperty(X, false, s.Owner, getAtom(X, "_XSETTINGS_SETTINGS"), getAtom(X, "_XSETTINGS_SETTINGS"), 0, 10240).Reply()
	if err != nil {
		panic(err)
	}
	data := reply.Value[:reply.ValueLen]

	var byteOrder binary.ByteOrder
	if data[0] == 1 {
		byteOrder = binary.BigEndian
	} else {
		byteOrder = binary.LittleEndian
	}
	buf := bytes.NewReader(data[4:])

	serial := readInterger(buf, byteOrder)
	numSettings := readInterger(buf, byteOrder)

	fmt.Println("serial:", serial, "Num:", numSettings)
	for i := uint32(0); i < numSettings; i++ {
		sType, name, _ := readHeader(buf, byteOrder)
		switch sType {
		case 0:
			v := readInterger(buf, byteOrder)
			fmt.Println(name, "=", v)
		case 1:
			v := readString(buf, byteOrder)
			fmt.Println(name, "=", v)
		case 2:
			r, g, b, a := readColor(buf, byteOrder)
			fmt.Println(name, "=", r, g, b, a)
		}
	}
}