package main import ( "bytes" "encoding/xml" "fmt" "log" "sort" ) // Context represents the protocol we're converting to Go, and a writer // buffer to write the Go source to. type Context struct { protocol *Protocol out *bytes.Buffer } func newContext() *Context { return &Context{ out: bytes.NewBuffer([]byte{}), } } // Putln calls put and adds a new line to the end of 'format'. func (c *Context) Putln(format string, v ...interface{}) { c.Put(format+"\n", v...) } // Put is a short alias to write to 'out'. func (c *Context) Put(format string, v ...interface{}) { _, err := c.out.WriteString(fmt.Sprintf(format, v...)) if err != nil { log.Fatalf("There was an error writing to context buffer: %s", err) } } // Morph is the big daddy of them all. It takes in an XML byte slice, // parse it, transforms the XML types into more usable types, // and writes Go code to the 'out' buffer. func (c *Context) Morph(xmlBytes []byte) { parsedXml := &XML{} err := xml.Unmarshal(xmlBytes, parsedXml) if err != nil { log.Fatal(err) } // Parse all imports parsedXml.Imports.Eval() // Translate XML types to nice types c.protocol = parsedXml.Translate(nil) c.protocol.AddAlignGaps() // Start with Go header. c.Putln("// Package %s is the X client API for the %s extension.", c.protocol.PkgName(), c.protocol.ExtXName) c.Putln("package %s", c.protocol.PkgName()) c.Putln("") c.Putln("// This file is automatically generated from %s.xml. "+ "Edit at your peril!", c.protocol.Name) c.Putln("") // Write imports. We always need to import at least xgb. // We also need to import xproto if it's an extension. c.Putln("import (") c.Putln("\"github.com/BurntSushi/xgb\"") c.Putln("") if c.protocol.isExt() { c.Putln("\"github.com/BurntSushi/xgb/xproto\"") } sort.Sort(Protocols(c.protocol.Imports)) for _, imp := range c.protocol.Imports { // We always import xproto, so skip it if it's explicitly imported if imp.Name == "xproto" { continue } c.Putln("\"github.com/BurntSushi/xgb/%s\"", imp.Name) } c.Putln(")") c.Putln("") // If this is an extension, create a function to initialize the extension // before it can be used. if c.protocol.isExt() { xname := c.protocol.ExtXName c.Putln("// Init must be called before using the %s extension.", xname) c.Putln("func Init(c *xgb.Conn) error {") c.Putln("reply, err := xproto.QueryExtension(c, %d, \"%s\").Reply()", len(xname), xname) c.Putln("switch {") c.Putln("case err != nil:") c.Putln("return err") c.Putln("case !reply.Present:") c.Putln("return xgb.Errorf(\"No extension named %s could be found on "+ "on the server.\")", xname) c.Putln("}") c.Putln("") c.Putln("c.ExtLock.Lock()") c.Putln("c.Extensions[\"%s\"] = reply.MajorOpcode", xname) c.Putln("c.ExtLock.Unlock()") c.Putln("for evNum, fun := range xgb.NewExtEventFuncs[\"%s\"] {", xname) c.Putln("xgb.NewEventFuncs[int(reply.FirstEvent) + evNum] = fun") c.Putln("}") c.Putln("for errNum, fun := range xgb.NewExtErrorFuncs[\"%s\"] {", xname) c.Putln("xgb.NewErrorFuncs[int(reply.FirstError) + errNum] = fun") c.Putln("}") c.Putln("return nil") c.Putln("}") c.Putln("") // Make sure newExtEventFuncs["EXT_NAME"] map is initialized. // Same deal for newExtErrorFuncs["EXT_NAME"] c.Putln("func init() {") c.Putln("xgb.NewExtEventFuncs[\"%s\"] = make(map[int]xgb.NewEventFun)", xname) c.Putln("xgb.NewExtErrorFuncs[\"%s\"] = make(map[int]xgb.NewErrorFun)", xname) c.Putln("}") c.Putln("") } else { // In the xproto package, we must provide a Setup function that uses // SetupBytes in xgb.Conn to return a SetupInfo structure. c.Putln("// Setup parses the setup bytes retrieved when") c.Putln("// connecting into a SetupInfo struct.") c.Putln("func Setup(c *xgb.Conn) *SetupInfo {") c.Putln("setup := new(SetupInfo)") c.Putln("SetupInfoRead(c.SetupBytes, setup)") c.Putln("return setup") c.Putln("}") c.Putln("") c.Putln("// DefaultScreen gets the default screen info from SetupInfo.") c.Putln("func (s *SetupInfo) DefaultScreen(c *xgb.Conn) *ScreenInfo {") c.Putln("return &s.Roots[c.DefaultScreen]") c.Putln("}") c.Putln("") } // Now write Go source code sort.Sort(Types(c.protocol.Types)) sort.Sort(Requests(c.protocol.Requests)) for _, typ := range c.protocol.Types { typ.Define(c) } for _, req := range c.protocol.Requests { req.Define(c) } }