Golang Object.Type方法代码示例

func isStringer(obj types.Object) bool {
	switch obj := obj.(type) {
	case *types.Func:
		if obj.Name() != "String" {
			return false
		}
		sig, ok := obj.Type().(*types.Signature)
		if !ok {
			return false
		}
		if sig.Recv() == nil {
			return false
		}
		if sig.Params().Len() != 0 {
			return false
		}
		res := sig.Results()
		if res.Len() != 1 {
			return false
		}
		ret := res.At(0).Type()
		if ret != types.Universe.Lookup("string").Type() {
			return false
		}
		return true
	default:
		return false
	}

	return false
}

func (f *Function) addParamObj(obj types.Object) *Parameter {
	name := obj.Name()
	if name == "" {
		name = fmt.Sprintf("arg%d", len(f.Params))
	}
	param := f.addParam(name, obj.Type(), obj.Pos())
	param.object = obj
	return param
}

// addSpilledParam declares a parameter that is pre-spilled to the
// stack; the function body will load/store the spilled location.
// Subsequent lifting will eliminate spills where possible.
//
func (f *Function) addSpilledParam(obj types.Object) {
	param := f.addParamObj(obj)
	spill := &Alloc{Comment: obj.Name()}
	spill.setType(types.NewPointer(obj.Type()))
	spill.setPos(obj.Pos())
	f.objects[obj] = spill
	f.Locals = append(f.Locals, spill)
	f.emit(spill)
	f.emit(&Store{Addr: spill, Val: param})
}

func formatMember(obj types.Object, maxname int) string {
	var buf bytes.Buffer
	fmt.Fprintf(&buf, "%-5s %-*s", tokenOf(obj), maxname, obj.Name())
	switch obj := obj.(type) {
	case *types.Const:
		fmt.Fprintf(&buf, " %s = %s", types.TypeString(obj.Pkg(), obj.Type()), obj.Val().String())

	case *types.Func:
		fmt.Fprintf(&buf, " %s", types.TypeString(obj.Pkg(), obj.Type()))

	case *types.TypeName:
		// Abbreviate long aggregate type names.
		var abbrev string
		switch t := obj.Type().Underlying().(type) {
		case *types.Interface:
			if t.NumMethods() > 1 {
				abbrev = "interface{...}"
			}
		case *types.Struct:
			if t.NumFields() > 1 {
				abbrev = "struct{...}"
			}
		}
		if abbrev == "" {
			fmt.Fprintf(&buf, " %s", types.TypeString(obj.Pkg(), obj.Type().Underlying()))
		} else {
			fmt.Fprintf(&buf, " %s", abbrev)
		}

	case *types.Var:
		fmt.Fprintf(&buf, " %s", types.TypeString(obj.Pkg(), obj.Type()))
	}
	return buf.String()
}

func (p *exporter) obj(obj types.Object) {
	if trace {
		p.tracef("object %s {\n", obj.Name())
		defer p.tracef("}\n")
	}

	switch obj := obj.(type) {
	case *types.Const:
		p.int(constTag)
		p.string(obj.Name())
		p.typ(obj.Type())
		p.value(obj.Val())
	case *types.TypeName:
		p.int(typeTag)
		// name is written by corresponding named type
		p.typ(obj.Type().(*types.Named))
	case *types.Var:
		p.int(varTag)
		p.string(obj.Name())
		p.typ(obj.Type())
	case *types.Func:
		p.int(funcTag)
		p.string(obj.Name())
		p.typ(obj.Type())
	default:
		panic(fmt.Sprintf("unexpected object type %T", obj))
	}
}

func (p *printer) printObj(obj types.Object) {
	p.print(obj.Name())

	typ, basic := obj.Type().Underlying().(*types.Basic)
	if basic && typ.Info()&types.IsUntyped != 0 {
		// don't write untyped types
	} else {
		p.print(" ")
		p.writeType(p.pkg, obj.Type())
	}

	if obj, ok := obj.(*types.Const); ok {
		floatFmt := basic && typ.Info()&(types.IsFloat|types.IsComplex) != 0
		p.print(" = ")
		p.print(valString(obj.Val(), floatFmt))
	}
}

func newFuncFrom(p *Package, parent string, obj types.Object, sig *types.Signature) (Func, error) {
	haserr := false
	res := sig.Results()
	var ret types.Type

	switch res.Len() {
	case 2:
		if !isErrorType(res.At(1).Type()) {
			return Func{}, fmt.Errorf(
				"bind: second result value must be of type error: %s",
				obj,
			)
		}
		haserr = true
		ret = res.At(0).Type()

	case 1:
		if isErrorType(res.At(0).Type()) {
			haserr = true
			ret = nil
		} else {
			ret = res.At(0).Type()
		}
	case 0:
		ret = nil
	default:
		return Func{}, fmt.Errorf("bind: too many results to return: %v", obj)
	}

	id := obj.Pkg().Name() + "_" + obj.Name()
	if parent != "" {
		id = obj.Pkg().Name() + "_" + parent + "_" + obj.Name()
	}

	return Func{
		pkg:  p,
		sig:  newSignatureFrom(p, sig),
		typ:  obj.Type(),
		name: obj.Name(),
		id:   id,
		doc:  p.getDoc(parent, obj),
		ret:  ret,
		err:  haserr,
	}, nil
}

func objectKind(obj types.Object) string {
	switch obj := obj.(type) {
	case *types.PkgName:
		return "imported package name"
	case *types.TypeName:
		return "type"
	case *types.Var:
		if obj.IsField() {
			return "field"
		}
	case *types.Func:
		if obj.Type().(*types.Signature).Recv() != nil {
			return "method"
		}
	}
	// label, func, var, const
	return strings.ToLower(strings.TrimPrefix(reflect.TypeOf(obj).String(), "*types."))
}

func (g *Grapher) makeDefInfo(obj types.Object) (*DefKey, *defInfo, error) {
	switch obj := obj.(type) {
	case *types.Builtin:
		return &DefKey{"builtin", []string{obj.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
	case *types.Nil:
		return &DefKey{"builtin", []string{"nil"}}, &defInfo{pkgscope: false, exported: true}, nil
	case *types.TypeName:
		if basic, ok := obj.Type().(*types.Basic); ok {
			return &DefKey{"builtin", []string{basic.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
		}
		if obj.Name() == "error" {
			return &DefKey{"builtin", []string{obj.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
		}
	case *types.PkgName:
		return &DefKey{obj.Imported().Path(), []string{}}, &defInfo{pkgscope: false, exported: true}, nil
	case *types.Const:
		var pkg string
		if obj.Pkg() == nil {
			pkg = "builtin"
		} else {
			pkg = obj.Pkg().Path()
		}
		if obj.Val().Kind() == exact.Bool && pkg == "builtin" {
			return &DefKey{pkg, []string{obj.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
		}
	}

	if obj.Pkg() == nil {
		// builtin
		return &DefKey{"builtin", []string{obj.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
	}

	path := g.path(obj)

	// Handle the case where a dir has 2 main packages that are not
	// intended to be compiled together and have overlapping def
	// paths. Prefix the def path with the filename.
	if obj.Pkg().Name() == "main" {
		p := g.program.Fset.Position(obj.Pos())
		path = append([]string{filepath.Base(p.Filename)}, path...)
	}

	return &DefKey{obj.Pkg().Path(), path}, &defInfo{pkgscope: g.pkgscope[obj], exported: g.exported[obj]}, nil
}

func (sym *symtab) addSymbol(obj types.Object) {
	fn := types.ObjectString(obj, nil)
	n := obj.Name()
	pkg := obj.Pkg()
	id := n
	if pkg != nil {
		id = pkg.Name() + "_" + n
	}
	switch obj.(type) {
	case *types.Const:
		sym.syms[fn] = &symbol{
			gopkg:   pkg,
			goobj:   obj,
			kind:    skConst,
			id:      id,
			goname:  n,
			cgoname: "cgo_const_" + id,
			cpyname: "cpy_const_" + id,
		}
		sym.addType(obj, obj.Type())

	case *types.Var:
		sym.syms[fn] = &symbol{
			gopkg:   pkg,
			goobj:   obj,
			kind:    skVar,
			id:      id,
			goname:  n,
			cgoname: "cgo_var_" + id,
			cpyname: "cpy_var_" + id,
		}
		sym.addType(obj, obj.Type())

	case *types.Func:
		sym.syms[fn] = &symbol{
			gopkg:   pkg,
			goobj:   obj,
			kind:    skFunc,
			id:      id,
			goname:  n,
			cgoname: "cgo_func_" + id,
			cpyname: "cpy_func_" + id,
		}
		sig := obj.Type().Underlying().(*types.Signature)
		sym.processTuple(sig.Params())
		sym.processTuple(sig.Results())

	case *types.TypeName:
		sym.addType(obj, obj.Type())

	default:
		panic(fmt.Errorf("gopy: handled object [%#v]", obj))
	}
}

func isExported(obj types.Object) bool {
	// https://golang.org/ref/spec#Exported_identifiers
	// An identifier is exported if both:
	// the first character of the identifier's name is a Unicode upper case letter (Unicode class "Lu"); and
	// the identifier is declared in the package block or it is a field name or method name.
	// All other identifiers are not exported.

	if !obj.Exported() {
		// does not start with an upper case letter
		return false
	}

	if v, ok := obj.(*types.Var); ok && v.IsField() {
		// is a field name
		return true
	}
	if sig, ok := obj.Type().(*types.Signature); ok && sig.Recv() != nil {
		// is a method name
		return true
	}
	// is declared in the package block
	return obj.Parent() == obj.Pkg().Scope()
}

// memberFromObject populates package pkg with a member for the
// typechecker object obj.
//
// For objects from Go source code, syntax is the associated syntax
// tree (for funcs and vars only); it will be used during the build
// phase.
//
func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node) {
	name := obj.Name()
	switch obj := obj.(type) {
	case *types.TypeName:
		pkg.Members[name] = &Type{
			object: obj,
			pkg:    pkg,
		}

	case *types.Const:
		c := &NamedConst{
			object: obj,
			Value:  NewConst(obj.Val(), obj.Type()),
			pkg:    pkg,
		}
		pkg.values[obj] = c.Value
		pkg.Members[name] = c

	case *types.Var:
		g := &Global{
			Pkg:    pkg,
			name:   name,
			object: obj,
			typ:    types.NewPointer(obj.Type()), // address
			pos:    obj.Pos(),
		}
		pkg.values[obj] = g
		pkg.Members[name] = g

	case *types.Func:
		sig := obj.Type().(*types.Signature)
		if sig.Recv() == nil && name == "init" {
			pkg.ninit++
			name = fmt.Sprintf("init#%d", pkg.ninit)
		}
		fn := &Function{
			name:      name,
			object:    obj,
			Signature: sig,
			syntax:    syntax,
			pos:       obj.Pos(),
			Pkg:       pkg,
			Prog:      pkg.Prog,
		}
		if syntax == nil {
			fn.Synthetic = "loaded from gc object file"
		}

		pkg.values[obj] = fn
		if sig.Recv() == nil {
			pkg.Members[name] = fn // package-level function
		}

	default: // (incl. *types.Package)
		panic("unexpected Object type: " + obj.String())
	}
}

func defKind(obj types.Object) string {
	switch obj := obj.(type) {
	case *types.PkgName:
		return definfo.Package
	case *types.Const:
		return definfo.Const
	case *types.TypeName:
		return definfo.Type
	case *types.Var:
		if obj.IsField() {
			return definfo.Field
		}
		return definfo.Var
	case *types.Func:
		sig := obj.Type().(*types.Signature)
		if sig.Recv() == nil {
			return definfo.Func
		} else {
			return definfo.Method
		}
	default:
		panic(fmt.Sprintf("unhandled obj type %T", obj))
	}
}

func getEnclosingStruct(object types.Object) types.Type {
	pkgScope := object.Pkg().Scope()
	s := pkgScope.Innermost(object.Pos())
	if s.Parent() == pkgScope {
		s = pkgScope
	}

	var obj types.Object
	for _, name := range s.Names() {
		o := s.Lookup(name)
		if o.Pos() <= object.Pos() && (obj == nil || o.Pos() > obj.Pos()) {
			obj = o
		}
	}

	if obj == nil {
		return nil
	}
	if obj == object {
		return obj.Type()
	}

	t := obj.Type().Underlying().(*types.Struct)
	for {
		var f types.Object
		for i := 0; i < t.NumFields(); i++ {
			field := t.Field(i)
			if field == object {
				return t
			}
			if field.Pos() <= object.Pos() && (f == nil || field.Pos() > f.Pos()) {
				f = field
			}
		}
		if fs, ok := f.Type().(*types.Struct); ok {
			t = fs
		} else {
			break
		}
	}

	return t
}

// addNamedLocal creates a local variable, adds it to function f and
// returns it.  Its name and type are taken from obj.  Subsequent
// calls to f.lookup(obj) will return the same local.
//
func (f *Function) addNamedLocal(obj types.Object) *Alloc {
	l := f.addLocal(obj.Type(), obj.Pos())
	l.Comment = obj.Name()
	f.objects[obj] = l
	return l
}