Golang Package.Scope方法代码示例

// FindQueryMethods locates all methods in the given package (assumed to be
// package database/sql) with a string parameter named "query".
func FindQueryMethods(sql *types.Package, ssa *ssa.Program) []*QueryMethod {
	methods := make([]*QueryMethod, 0)
	scope := sql.Scope()
	for _, name := range scope.Names() {
		o := scope.Lookup(name)
		if !o.Exported() {
			continue
		}
		if _, ok := o.(*types.TypeName); !ok {
			continue
		}
		n := o.Type().(*types.Named)
		for i := 0; i < n.NumMethods(); i++ {
			m := n.Method(i)
			if !m.Exported() {
				continue
			}
			s := m.Type().(*types.Signature)
			if num, ok := FuncHasQuery(s); ok {
				methods = append(methods, &QueryMethod{
					Func:     m,
					SSA:      ssa.FuncValue(m),
					ArgCount: s.Params().Len(),
					Param:    num,
				})
			}
		}
	}
	return methods
}

func (c *converter) convertPackage(v *gotypes.Package) *types.Package {
	if v == nil {
		return nil
	}
	if v, ok := c.converted[v]; ok {
		return v.(*types.Package)
	}

	ret := types.NewPackage(v.Path(), v.Name())
	if c.ret == nil {
		c.ret = ret
	}
	c.converted[v] = ret

	var imports []*types.Package
	for _, imported := range v.Imports() {
		imports = append(imports, c.convertPackage(imported))
	}
	ret.SetImports(imports)

	c.convertScope(ret.Scope(), v.Scope())

	for _, iface := range c.ifaces {
		iface.Complete()
	}

	return ret
}

//!+
func PrintSkeleton(pkg *types.Package, ifacename, concname string) error {
	obj := pkg.Scope().Lookup(ifacename)
	if obj == nil {
		return fmt.Errorf("%s.%s not found", pkg.Path(), ifacename)
	}
	if _, ok := obj.(*types.TypeName); !ok {
		return fmt.Errorf("%v is not a named type", obj)
	}
	iface, ok := obj.Type().Underlying().(*types.Interface)
	if !ok {
		return fmt.Errorf("type %v is a %T, not an interface",
			obj, obj.Type().Underlying())
	}
	// Use first letter of type name as receiver parameter.
	if !isValidIdentifier(concname) {
		return fmt.Errorf("invalid concrete type name: %q", concname)
	}
	r, _ := utf8.DecodeRuneInString(concname)

	fmt.Printf("// *%s implements %s.%s.\n", concname, pkg.Path(), ifacename)
	fmt.Printf("type %s struct{}\n", concname)
	mset := types.NewMethodSet(iface)
	for i := 0; i < mset.Len(); i++ {
		meth := mset.At(i).Obj()
		sig := types.TypeString(meth.Type(), (*types.Package).Name)
		fmt.Printf("func (%c *%s) %s%s {\n\tpanic(\"unimplemented\")\n}\n",
			r, concname, meth.Name(),
			strings.TrimPrefix(sig, "func"))
	}
	return nil
}

func find(pkg *types.Package, iface string) (*types.Interface, error) {
	scope := pkg.Scope()
	names := scope.Names()
	for _, n := range names {
		obj := scope.Lookup(n)

		tn, ok := obj.(*types.TypeName)
		if !ok {
			continue
		}
		if tn.Name() != iface {
			continue
		}
		if !obj.Exported() {
			return nil, fmt.Errorf("%s should exported", iface)
		}
		t := tn.Type().Underlying()
		i, ok := t.(*types.Interface)
		if !ok {
			return nil, fmt.Errorf("exptected interface, got %s for %s", t, iface)
		}
		return i, nil
	}
	return nil, fmt.Errorf("%s not found in %s", iface, pkg.Name())
}

func describePackage(qpos *queryPos, path []ast.Node) (*describePackageResult, error) {
	var description string
	var pkg *types.Package
	switch n := path[0].(type) {
	case *ast.ImportSpec:
		var obj types.Object
		if n.Name != nil {
			obj = qpos.info.Defs[n.Name]
		} else {
			obj = qpos.info.Implicits[n]
		}
		pkgname, _ := obj.(*types.PkgName)
		if pkgname == nil {
			return nil, fmt.Errorf("can't import package %s", n.Path.Value)
		}
		pkg = pkgname.Imported()
		description = fmt.Sprintf("import of package %q", pkg.Path())

	case *ast.Ident:
		if _, isDef := path[1].(*ast.File); isDef {
			// e.g. package id
			pkg = qpos.info.Pkg
			description = fmt.Sprintf("definition of package %q", pkg.Path())
		} else {
			// e.g. import id "..."
			//  or  id.F()
			pkg = qpos.info.ObjectOf(n).(*types.PkgName).Imported()
			description = fmt.Sprintf("reference to package %q", pkg.Path())
		}

	default:
		// Unreachable?
		return nil, fmt.Errorf("unexpected AST for package: %T", n)
	}

	var members []*describeMember
	// NB: "unsafe" has no types.Package
	if pkg != nil {
		// Enumerate the accessible package members
		// in lexicographic order.
		for _, name := range pkg.Scope().Names() {
			if pkg == qpos.info.Pkg || ast.IsExported(name) {
				mem := pkg.Scope().Lookup(name)
				var methods []*types.Selection
				if mem, ok := mem.(*types.TypeName); ok {
					methods = accessibleMethods(mem.Type(), qpos.info.Pkg)
				}
				members = append(members, &describeMember{
					mem,
					methods,
				})

			}
		}
	}

	return &describePackageResult{qpos.fset, path[0], description, pkg, members}, nil
}

func getMethods(pkg *types.Package, typename string) map[string]*types.Func {
	r := make(map[string]*types.Func)
	mset := types.NewMethodSet(types.NewPointer(pkg.Scope().Lookup(typename).Type()))
	for i := 0; i < mset.Len(); i++ {
		fn := mset.At(i).Obj().(*types.Func)
		r[fn.Name()] = fn
	}
	return r
}

func declTypeName(pkg *types.Package, name string) *types.TypeName {
	scope := pkg.Scope()
	if obj := scope.Lookup(name); obj != nil {
		return obj.(*types.TypeName)
	}
	obj := types.NewTypeName(token.NoPos, pkg, name, nil)
	// a named type may be referred to before the underlying type
	// is known - set it up
	types.NewNamed(obj, nil, nil)
	scope.Insert(obj)
	return obj
}

// export emits the exported package features.
func (w *Walker) export(pkg *types.Package) {
	if *verbose {
		log.Println(pkg)
	}
	pop := w.pushScope("pkg " + pkg.Path())
	w.current = pkg
	scope := pkg.Scope()
	for _, name := range scope.Names() {
		if ast.IsExported(name) {
			w.emitObj(scope.Lookup(name))
		}
	}
	pop()
}

// addOwners updates pi.owner from the types in pkg, adding mapping from fields
// of package-level named struct types to the owning named struct type; from
// methods of package-level named interface types to the owning named interface
// type; and from parameters of package-level named function or method types to
// the owning named function or method.
//
// This relation is used to construct signatures for these fields/methods,
// since they may be referenced from another package and thus need
// deterministic names. An object does expose its "owner"; indeed, it may have
// several.
//
// Caveats:
//
// (1) This mapping is deterministic but not necessarily the best one according
// to the original syntax, to which, in general, we do not have access.  In
// these two examples, the type checker considers field X as belonging equally
// to types T and U, even though according the syntax, it belongs primarily to
// T in the first example and U in the second:
//
//      type T struct {X int}
//      type U T
//
//      type T U
//      type U struct {X int}
//
// Similarly:
//
//      type U struct {X int}
//      type V struct {U}
//
// TODO(adonovan): [email protected] points out a useful heuristic: in a case of struct
// or interface embedding, if one struct/interface has fewer fields/methods,
// then it must be the primary one.
//
// (2) This pass is not exhaustive: there remain objects that may be referenced
// from outside the package but for which we can't easily come up with good
// names.  Here are some examples:
//
//      // package p
//      var V1, V2 struct {X int} = ...
//      func F() struct{X int} {...}
//      type T struct {
//              Y struct { X int }
//      }
//
//      // main
//      p.V2.X = 1
//      print(p.F().X)
//      new(p.T).Y[0].X
//
// Also note that there may be arbitrary pointer, struct, chan, map, array, and
// slice type constructors between the type of the exported package member (V2,
// F or T) and the type of its X subelement.  For now, we simply ignore such
// names.  They should be rare in readable code.
func (pi *PackageInfo) addOwners(pkg *types.Package) {
	scope := pkg.Scope()
	for _, name := range scope.Names() {
		switch obj := scope.Lookup(name).(type) {
		case *types.TypeName:
			switch t := obj.Type().Underlying().(type) {
			case *types.Struct:
				// Inspect the fields of a struct.
				for i := 0; i < t.NumFields(); i++ {
					f := t.Field(i)
					if f.Pkg() != pkg {
						continue // wrong package
					}
					if _, ok := pi.owner[f]; !ok {
						pi.owner[f] = obj
					}
				}
			case *types.Interface:
				// Inspect the declared methods of an interface.
				for i := 0; i < t.NumMethods(); i++ {
					m := t.Method(i)
					if m.Pkg() != pkg {
						continue // wrong package
					}
					if _, ok := pi.owner[m]; !ok {
						pi.owner[m] = obj
					}
				}
			}

		case *types.Func:
			// Inspect the receiver, parameters, and result values.
			fsig := obj.Type().(*types.Signature)
			if recv := fsig.Recv(); recv != nil {
				pi.owner[recv] = obj
			}
			if params := fsig.Params(); params != nil {
				for i := 0; i < params.Len(); i++ {
					pi.owner[params.At(i)] = obj
				}
			}
			if res := fsig.Results(); res != nil {
				for i := 0; i < res.Len(); i++ {
					pi.owner[res.At(i)] = obj
				}
			}
//.........这里部分代码省略.........

func TestIssue13898(t *testing.T) {
	skipSpecialPlatforms(t)

	// This package only handles gc export data.
	if runtime.Compiler != "gc" {
		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
		return
	}

	// import go/internal/gcimporter which imports go/types partially
	imports := make(map[string]*types.Package)
	_, err := Import(imports, "go/internal/gcimporter", ".")
	if err != nil {
		t.Fatal(err)
	}

	// look for go/types package
	var goTypesPkg *types.Package
	for path, pkg := range imports {
		if path == "go/types" {
			goTypesPkg = pkg
			break
		}
	}
	if goTypesPkg == nil {
		t.Fatal("go/types not found")
	}

	// look for go/types.Object type
	obj := goTypesPkg.Scope().Lookup("Object")
	if obj == nil {
		t.Fatal("go/types.Object not found")
	}
	typ, ok := obj.Type().(*types.Named)
	if !ok {
		t.Fatalf("go/types.Object type is %v; wanted named type", typ)
	}

	// lookup go/types.Object.Pkg method
	m, index, indirect := types.LookupFieldOrMethod(typ, false, nil, "Pkg")
	if m == nil {
		t.Fatalf("go/types.Object.Pkg not found (index = %v, indirect = %v)", index, indirect)
	}

	// the method must belong to go/types
	if m.Pkg().Path() != "go/types" {
		t.Fatalf("found %v; want go/types", m.Pkg())
	}
}

func (p *importer) obj(pkg *types.Package) {
	var obj types.Object
	switch tag := p.int(); tag {
	case constTag:
		obj = types.NewConst(token.NoPos, pkg, p.string(), p.typ(), p.value())
	case typeTag:
		// type object is added to scope via respective named type
		_ = p.typ().(*types.Named)
		return
	case varTag:
		obj = types.NewVar(token.NoPos, pkg, p.string(), p.typ())
	case funcTag:
		obj = types.NewFunc(token.NoPos, pkg, p.string(), p.typ().(*types.Signature))
	default:
		panic(fmt.Sprintf("unexpected object tag %d", tag))
	}

	if alt := pkg.Scope().Insert(obj); alt != nil {
		panic(fmt.Sprintf("%s already declared", alt.Name()))
	}
}

// ExportData serializes the interface (exported package objects)
// of package pkg and returns the corresponding data. The export
// format is described elsewhere (TODO).
func ExportData(pkg *types.Package) []byte {
	p := exporter{
		data:     append([]byte(magic), format()),
		pkgIndex: make(map[*types.Package]int),
		typIndex: make(map[types.Type]int),
	}

	// populate typIndex with predeclared types
	for _, t := range predeclared {
		p.typIndex[t] = len(p.typIndex)
	}

	if trace {
		p.tracef("export %s\n", pkg.Name())
		defer p.tracef("\n")
	}

	p.string(version)

	p.pkg(pkg)

	// collect exported objects from package scope
	var list []types.Object
	scope := pkg.Scope()
	for _, name := range scope.Names() {
		if exported(name) {
			list = append(list, scope.Lookup(name))
		}
	}

	// write objects
	p.int(len(list))
	for _, obj := range list {
		p.obj(obj)
	}

	return p.data
}

// BExportData returns binary export data for pkg.
// If no file set is provided, position info will be missing.
func BExportData(fset *token.FileSet, pkg *types.Package) []byte {
	p := exporter{
		fset:          fset,
		strIndex:      map[string]int{"": 0}, // empty string is mapped to 0
		pkgIndex:      make(map[*types.Package]int),
		typIndex:      make(map[types.Type]int),
		posInfoFormat: true, // TODO(gri) might become a flag, eventually
	}

	// first byte indicates low-level encoding format
	var format byte = 'c' // compact
	if debugFormat {
		format = 'd'
	}
	p.rawByte(format)

	format = 'n' // track named types only
	if trackAllTypes {
		format = 'a'
	}
	p.rawByte(format)

	// posInfo exported or not?
	p.bool(p.posInfoFormat)

	// --- generic export data ---

	if trace {
		p.tracef("\n--- generic export data ---\n")
		if p.indent != 0 {
			log.Fatalf("gcimporter: incorrect indentation %d", p.indent)
		}
	}

	if trace {
		p.tracef("version = ")
	}
	p.string(exportVersion)
	if trace {
		p.tracef("\n")
	}

	// populate type map with predeclared "known" types
	for index, typ := range predeclared {
		p.typIndex[typ] = index
	}
	if len(p.typIndex) != len(predeclared) {
		log.Fatalf("gcimporter: duplicate entries in type map?")
	}

	// write package data
	p.pkg(pkg, true)
	if trace {
		p.tracef("\n")
	}

	// write objects
	objcount := 0
	scope := pkg.Scope()
	for _, name := range scope.Names() {
		if !ast.IsExported(name) {
			continue
		}
		if trace {
			p.tracef("\n")
		}
		p.obj(scope.Lookup(name))
		objcount++
	}

	// indicate end of list
	if trace {
		p.tracef("\n")
	}
	p.tag(endTag)

	// for self-verification only (redundant)
	p.int(objcount)

	if trace {
		p.tracef("\n")
	}

	// --- end of export data ---

	return p.out.Bytes()
}

func (p *printer) printPackage(pkg *types.Package, filter func(types.Object) bool) {
	// collect objects by kind
	var (
		consts   []*types.Const
		typem    []*types.Named    // non-interface types with methods
		typez    []*types.TypeName // interfaces or types without methods
		vars     []*types.Var
		funcs    []*types.Func
		builtins []*types.Builtin
		methods  = make(map[*types.Named][]*types.Selection) // method sets for named types
	)
	scope := pkg.Scope()
	for _, name := range scope.Names() {
		obj := scope.Lookup(name)
		if obj.Exported() {
			// collect top-level exported and possibly filtered objects
			if filter == nil || filter(obj) {
				switch obj := obj.(type) {
				case *types.Const:
					consts = append(consts, obj)
				case *types.TypeName:
					// group into types with methods and types without
					if named, m := methodsFor(obj); named != nil {
						typem = append(typem, named)
						methods[named] = m
					} else {
						typez = append(typez, obj)
					}
				case *types.Var:
					vars = append(vars, obj)
				case *types.Func:
					funcs = append(funcs, obj)
				case *types.Builtin:
					// for unsafe.Sizeof, etc.
					builtins = append(builtins, obj)
				}
			}
		} else if filter == nil {
			// no filtering: collect top-level unexported types with methods
			if obj, _ := obj.(*types.TypeName); obj != nil {
				// see case *types.TypeName above
				if named, m := methodsFor(obj); named != nil {
					typem = append(typem, named)
					methods[named] = m
				}
			}
		}
	}

	p.printf("package %s  // %q\n", pkg.Name(), pkg.Path())

	p.printDecl("const", len(consts), func() {
		for _, obj := range consts {
			p.printObj(obj)
			p.print("\n")
		}
	})

	p.printDecl("var", len(vars), func() {
		for _, obj := range vars {
			p.printObj(obj)
			p.print("\n")
		}
	})

	p.printDecl("type", len(typez), func() {
		for _, obj := range typez {
			p.printf("%s ", obj.Name())
			p.writeType(p.pkg, obj.Type().Underlying())
			p.print("\n")
		}
	})

	// non-interface types with methods
	for _, named := range typem {
		first := true
		if obj := named.Obj(); obj.Exported() {
			if first {
				p.print("\n")
				first = false
			}
			p.printf("type %s ", obj.Name())
			p.writeType(p.pkg, named.Underlying())
			p.print("\n")
		}
		for _, m := range methods[named] {
			if obj := m.Obj(); obj.Exported() {
				if first {
					p.print("\n")
					first = false
				}
				p.printFunc(m.Recv(), obj.(*types.Func))
				p.print("\n")
			}
		}
	}

	if len(funcs) > 0 {
		p.print("\n")
		for _, obj := range funcs {
//.........这里部分代码省略.........

// BExportData returns binary export data for pkg.
// If no file set is provided, position info will be missing.
func BExportData(fset *token.FileSet, pkg *types.Package) []byte {
	p := exporter{
		fset:          fset,
		strIndex:      map[string]int{"": 0}, // empty string is mapped to 0
		pkgIndex:      make(map[*types.Package]int),
		typIndex:      make(map[types.Type]int),
		reexported:    make(map[types.Object]bool),
		posInfoFormat: true, // TODO(gri) might become a flag, eventually
	}

	// write version info
	// The version string must start with "version %d" where %d is the version
	// number. Additional debugging information may follow after a blank; that
	// text is ignored by the importer.
	p.rawStringln(fmt.Sprintf("version %d", exportVersion))
	var debug string
	if debugFormat {
		debug = "debug"
	}
	p.rawStringln(debug) // cannot use p.bool since it's affected by debugFormat; also want to see this clearly
	p.bool(trackAllTypes)
	p.bool(p.posInfoFormat)

	// --- generic export data ---

	// populate type map with predeclared "known" types
	for index, typ := range predeclared {
		p.typIndex[typ] = index
	}
	if len(p.typIndex) != len(predeclared) {
		log.Fatalf("gcimporter: duplicate entries in type map?")
	}

	// write package data
	p.pkg(pkg, true)
	if trace {
		p.tracef("\n")
	}

	// write objects
	objcount := 0
	scope := pkg.Scope()
	for _, name := range scope.Names() {
		if !ast.IsExported(name) {
			continue
		}
		if trace {
			p.tracef("\n")
		}
		p.obj(scope.Lookup(name))
		objcount++
	}

	// indicate end of list
	if trace {
		p.tracef("\n")
	}
	p.tag(endTag)

	// for self-verification only (redundant)
	p.int(objcount)

	if trace {
		p.tracef("\n")
	}

	// --- end of export data ---

	return p.out.Bytes()
}