Golang Object.String方法代码示例

// lookup returns the address of the named variable identified by obj
// that is local to function f or one of its enclosing functions.
// If escaping, the reference comes from a potentially escaping pointer
// expression and the referent must be heap-allocated.
//
func (f *Function) lookup(obj types.Object, escaping bool) Value {
	if v, ok := f.objects[obj]; ok {
		if alloc, ok := v.(*Alloc); ok && escaping {
			alloc.Heap = true
		}
		return v // function-local var (address)
	}

	// Definition must be in an enclosing function;
	// plumb it through intervening closures.
	if f.parent == nil {
		panic("no ssa.Value for " + obj.String())
	}
	outer := f.parent.lookup(obj, true) // escaping
	v := &FreeVar{
		name:   obj.Name(),
		typ:    outer.Type(),
		pos:    outer.Pos(),
		outer:  outer,
		parent: f,
	}
	f.objects[obj] = v
	f.FreeVars = append(f.FreeVars, v)
	return v
}

// 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 (w *Walker) emitObj(obj types.Object) {
	switch obj := obj.(type) {
	case *types.Const:
		w.emitf("const %s %s", obj.Name(), w.typeString(obj.Type()))
		w.emitf("const %s = %s", obj.Name(), obj.Val())
	case *types.Var:
		w.emitf("var %s %s", obj.Name(), w.typeString(obj.Type()))
	case *types.TypeName:
		w.emitType(obj)
	case *types.Func:
		w.emitFunc(obj)
	default:
		panic("unknown object: " + obj.String())
	}
}

func (w *Walker) emitObj(obj types.Object) {
	switch obj := obj.(type) {
	case *types.Const:
		w.emitf("const %s %s", obj.Name(), w.typeString(obj.Type()))
		x := obj.Val()
		short := x.String()
		exact := x.ExactString()
		if short == exact {
			w.emitf("const %s = %s", obj.Name(), short)
		} else {
			w.emitf("const %s = %s  // %s", obj.Name(), short, exact)
		}
	case *types.Var:
		w.emitf("var %s %s", obj.Name(), w.typeString(obj.Type()))
	case *types.TypeName:
		w.emitType(obj)
	case *types.Func:
		w.emitFunc(obj)
	default:
		panic("unknown object: " + obj.String())
	}
}

func formatNode(n ast.Node, obj types.Object, prog *loader.Program) string {
	var nc ast.Node
	// Render a copy of the node with no documentation.
	// We emit the documentation ourself.
	switch n := n.(type) {
	case *ast.FuncDecl:
		cp := *n
		cp.Doc = nil
		// Don't print the whole function body
		cp.Body = nil
		nc = &cp
	case *ast.GenDecl:
		cp := *n
		cp.Doc = nil
		if len(n.Specs) > 0 {
			// Only print this one type, not all the types in the
			// gendecl
			switch n.Specs[0].(type) {
			case *ast.TypeSpec:
				spec := findTypeSpec(n, obj.Pos())
				if spec != nil {
					specCp := *spec
					if *showUnexportedFields == false {
						trimUnexportedElems(&specCp)
					}
					specCp.Doc = nil
					cp.Specs = []ast.Spec{&specCp}
				}
				cp.Lparen = 0
				cp.Rparen = 0
			case *ast.ValueSpec:
				spec := findVarSpec(n, obj.Pos())
				if spec != nil {
					specCp := *spec
					specCp.Doc = nil
					cp.Specs = []ast.Spec{&specCp}
				}
				cp.Lparen = 0
				cp.Rparen = 0
			}
		}
		nc = &cp
	case *ast.Field:
		// Not supported by go/printer

		// TODO(dominikh): Methods in interfaces are syntactically
		// represented as fields. Using types.Object.String for those
		// causes them to look different from real functions.
		// go/printer doesn't include the import paths in names, while
		// Object.String does. Fix that.

		return obj.String()
	default:
		return obj.String()
	}

	buf := &bytes.Buffer{}
	cfg := printer.Config{Mode: printer.UseSpaces | printer.TabIndent, Tabwidth: 8}
	err := cfg.Fprint(buf, prog.Fset, nc)
	if err != nil {
		return obj.String()
	}
	return buf.String()
}