Golang Type.Key方法代碼示例

func typeIsOrContainsVerbotenImpl(t reflect.Type, verboten reflect.Kind) bool {
	switch t.Kind() {
	case verboten:
		return true

	case reflect.Map:
		if typeIsOrContainsVerbotenLocked(t.Key(), verboten) || typeIsOrContainsVerbotenLocked(t.Elem(), verboten) {
			return true
		}

	case reflect.Array, reflect.Ptr, reflect.Slice:
		if typeIsOrContainsVerbotenLocked(t.Elem(), verboten) {
			return true
		}

	case reflect.Struct:
		for i := 0; i < t.NumField(); i++ {
			if typeIsOrContainsVerbotenLocked(t.Field(i).Type, verboten) {
				return true
			}
		}

	case reflect.Chan, reflect.Func, reflect.Interface:
		// Not strictly correct, but cloning these kinds is not allowed.
		return true

	}

	return false
}

// verifyHandler ensures that the given t is a function with the following signature:
// func(json.Context, *ArgType)(*ResType, error)
func verifyHandler(t reflect.Type) error {
	if t.NumIn() != 2 || t.NumOut() != 2 {
		return fmt.Errorf("handler should be of format func(json.Context, *ArgType) (*ResType, error)")
	}

	isStructPtr := func(t reflect.Type) bool {
		return t.Kind() == reflect.Ptr && t.Elem().Kind() == reflect.Struct
	}
	isMap := func(t reflect.Type) bool {
		return t.Kind() == reflect.Map && t.Key().Kind() == reflect.String
	}
	validateArgRes := func(t reflect.Type, name string) error {
		if !isStructPtr(t) && !isMap(t) {
			return fmt.Errorf("%v should be a pointer to a struct, or a map[string]interface{}", name)
		}
		return nil
	}

	if t.In(0) != typeOfContext {
		return fmt.Errorf("arg0 should be of type json.Context")
	}
	if err := validateArgRes(t.In(1), "second argument"); err != nil {
		return err
	}
	if err := validateArgRes(t.Out(0), "first return value"); err != nil {
		return err
	}
	if !t.Out(1).AssignableTo(typeOfError) {
		return fmt.Errorf("second return value should be an error")
	}

	return nil
}

func getOrCreateSchema(definitions Definitions, t reflect.Type) *Schema {
	var result Schema
	if t.Kind() == reflect.Ptr {
		t = t.Elem()
	}

	if t.Kind() == reflect.Map {
		if t.Key().Kind() != reflect.String {
			panic("swagger supports only maps with string keys")
		}
		result.Type = "object"
		result.AdditionalProperties = getOrCreateSchema(definitions, t.Elem())
		return &result
	}

	if t.Kind() == reflect.Interface {
		result.Type = "object"
		return &result
	}

	result.Type = typeName(t)
	if result.Type == "object" {
		name := t.String()
		if _, ok := definitions[name]; ok {
			result = Schema{Ref: "#/definitions/" + name}
			return &result
		}
		definitions[name] = result

		if t.NumField() > 0 {
			result.Properties = Properties{}
		}
		for i := 0; i < t.NumField(); i++ {
			field := t.Field(i)
			if field.PkgPath != "" {
				continue
			}
			name := field.Tag.Get("json")
			if name == "" {
				name = field.Tag.Get("key")
				if name == "" {
					name = field.Name
				}
			}
			if field.Type.Kind() != reflect.Ptr {
				result.Required = append(result.Required, name)
			}
			fieldSchema := getOrCreateSchema(definitions, field.Type)
			fieldSchema.Description = field.Tag.Get("description")
			result.Properties[name] = fieldSchema
		}
		definitions[name] = result
		result = Schema{Ref: "#/definitions/" + name}
	} else if result.Type == "array" {
		itemsSchema := getOrCreateSchema(definitions, t.Elem())
		result.Items = &Items{*itemsSchema}
	}

	return &result
}

func copyTableToMap(L *lua.State, t reflect.Type, idx int, visited map[uintptr]interface{}) interface{} {
	if t == nil {
		t = tmap
	}
	te, tk := t.Elem(), t.Key()
	m := reflect.MakeMap(t)

	// See copyTableToSlice.
	ptr := L.ToPointer(idx)
	if !luaIsEmpty(L, idx) {
		visited[ptr] = m.Interface()
	}

	L.PushNil()
	if idx < 0 {
		idx--
	}
	for L.Next(idx) != 0 {
		// key at -2, value at -1
		key := reflect.ValueOf(luaToGo(L, tk, -2, visited))
		val := reflect.ValueOf(luaToGo(L, te, -1, visited))
		if val.Interface() == nullv.Interface() {
			val = reflect.Zero(te)
		}
		m.SetMapIndex(key, val)
		L.Pop(1)
	}
	return m.Interface()
}

// Add all necessary imports for the type, recursing as appropriate.
func addImportsForType(imports importMap, t reflect.Type) {
	// Add any import needed for the type itself.
	addImportForType(imports, t)

	// Handle special cases where recursion is needed.
	switch t.Kind() {
	case reflect.Array, reflect.Chan, reflect.Ptr, reflect.Slice:
		addImportsForType(imports, t.Elem())

	case reflect.Func:
		// Input parameters.
		for i := 0; i < t.NumIn(); i++ {
			addImportsForType(imports, t.In(i))
		}

		// Return values.
		for i := 0; i < t.NumOut(); i++ {
			addImportsForType(imports, t.Out(i))
		}

	case reflect.Map:
		addImportsForType(imports, t.Key())
		addImportsForType(imports, t.Elem())
	}
}

func (g *conversionGenerator) typeName(inType reflect.Type) string {
	switch inType.Kind() {
	case reflect.Map:
		return fmt.Sprintf("map[%s]%s", g.typeName(inType.Key()), g.typeName(inType.Elem()))
	case reflect.Slice:
		return fmt.Sprintf("[]%s", g.typeName(inType.Elem()))
	case reflect.Ptr:
		return fmt.Sprintf("*%s", g.typeName(inType.Elem()))
	default:
		typeWithPkg := fmt.Sprintf("%s", inType)
		slices := strings.Split(typeWithPkg, ".")
		if len(slices) == 1 {
			// Default package.
			return slices[0]
		}
		if len(slices) == 2 {
			pkg := slices[0]
			if val, found := g.pkgOverwrites[pkg]; found {
				pkg = val
			}
			if pkg != "" {
				pkg = pkg + "."
			}
			return pkg + slices[1]
		}
		panic("Incorrect type name: " + typeWithPkg)
	}
}

func newMapEncoder(t reflect.Type) encoderFunc {
	if t.Key().Kind() != reflect.String && !t.Key().Implements(textMarshalerType) {
		return unsupportedTypeEncoder
	}
	me := &mapEncoder{typeEncoder(t.Elem())}
	return me.encode
}

func evalCompositeLitMap(ctx *Ctx, t reflect.Type, lit *CompositeLit, env *Env) (reflect.Value, error) {

	m := reflect.MakeMap(t)

	kT := knownType{t.Key()}
	vT := knownType{t.Elem()}
	for _, elt := range lit.Elts {
		kv := elt.(*KeyValueExpr)
		k, err := evalTypedExpr(ctx, kv.Key.(Expr), kT, env)
		if err != nil {
			return reflect.Value{}, err
		}
		if kT[0].Kind() == reflect.Interface {
			dynamicT := k[0].Elem().Type()
			if !isStaticTypeComparable(dynamicT) {
				return reflect.Value{}, PanicUnhashableType{dynamicT}
			}
		}
		v, err := evalTypedExpr(ctx, kv.Value.(Expr), vT, env)
		if err != nil {
			return reflect.Value{}, err
		}
		m.SetMapIndex(k[0], v[0])
	}
	return m, nil
}

func (g *conversionGenerator) typeName(inType reflect.Type) string {
	switch inType.Kind() {
	case reflect.Slice:
		return fmt.Sprintf("[]%s", g.typeName(inType.Elem()))
	case reflect.Ptr:
		return fmt.Sprintf("*%s", g.typeName(inType.Elem()))
	case reflect.Map:
		if len(inType.Name()) == 0 {
			return fmt.Sprintf("map[%s]%s", g.typeName(inType.Key()), g.typeName(inType.Elem()))
		}
		fallthrough
	default:
		pkg, name := inType.PkgPath(), inType.Name()
		if len(name) == 0 && inType.Kind() == reflect.Struct {
			return "struct{}"
		}
		if len(pkg) == 0 {
			// Default package.
			return name
		}
		if val, found := g.pkgOverwrites[pkg]; found {
			pkg = val
		}
		if len(pkg) == 0 {
			return name
		}
		short := g.addImportByPath(pkg)
		if len(short) > 0 {
			return fmt.Sprintf("%s.%s", short, name)
		}
		return name
	}
}

// mapEncodeScratch returns a new reflect.Value matching the map's value type,
// and a structPointer suitable for passing to an encoder or sizer.
func mapEncodeScratch(mapType reflect.Type) (keycopy, valcopy reflect.Value, keybase, valbase structPointer) {
	// Prepare addressable doubly-indirect placeholders for the key and value types.
	// This is needed because the element-type encoders expect **T, but the map iteration produces T.

	keycopy = reflect.New(mapType.Key()).Elem()                 // addressable K
	keyptr := reflect.New(reflect.PtrTo(keycopy.Type())).Elem() // addressable *K
	keyptr.Set(keycopy.Addr())                                  //
	keybase = toStructPointer(keyptr.Addr())                    // **K

	// Value types are more varied and require special handling.
	switch mapType.Elem().Kind() {
	case reflect.Slice:
		// []byte
		var dummy []byte
		valcopy = reflect.ValueOf(&dummy).Elem() // addressable []byte
		valbase = toStructPointer(valcopy.Addr())
	case reflect.Ptr:
		// message; the generated field type is map[K]*Msg (so V is *Msg),
		// so we only need one level of indirection.
		valcopy = reflect.New(mapType.Elem()).Elem() // addressable V
		valbase = toStructPointer(valcopy.Addr())
	default:
		// everything else
		valcopy = reflect.New(mapType.Elem()).Elem()                // addressable V
		valptr := reflect.New(reflect.PtrTo(valcopy.Type())).Elem() // addressable *V
		valptr.Set(valcopy.Addr())                                  //
		valbase = toStructPointer(valptr.Addr())                    // **V
	}
	return
}

func newMapEncoder(t reflect.Type, vx reflect.Value) encoderFunc {
	if t.Key().Kind() != reflect.String {
		return unsupportedTypeEncoder
	}
	me := &mapEncoder{typeEncoder(vx.Type().Elem(), reflect.Value{})}
	return me.encode
}

// unify attempts to satisfy a pair of types, where the `param` type is the
// expected type of a function argument and the `input` type is the known
// type of a function argument. The `param` type may be parametric (that is,
// it may contain a type that is convertible to TypeVariable) but the
// `input` type may *not* be parametric.
//
// Any failure to unify the two types results in a panic.
//
// The end result of unification is a type environment: a set of substitutions
// from type variable to a Go type.
func (tp typePair) unify(param, input reflect.Type) error {
	if tyname := tyvarName(input); len(tyname) > 0 {
		return tp.error("Type variables are not allowed in the types of " +
			"arguments.")
	}
	if tyname := tyvarName(param); len(tyname) > 0 {
		if cur, ok := tp.tyenv[tyname]; ok && cur != input {
			return tp.error("Type variable %s expected type '%s' but got '%s'.",
				tyname, cur, input)
		} else if !ok {
			tp.tyenv[tyname] = input
		}
		return nil
	}
	if param.Kind() != input.Kind() {
		return tp.error("Cannot unify different kinds of types '%s' and '%s'.",
			param, input)
	}

	switch param.Kind() {
	case reflect.Array:
		return tp.unify(param.Elem(), input.Elem())
	case reflect.Chan:
		if param.ChanDir() != input.ChanDir() {
			return tp.error("Cannot unify '%s' with '%s' "+
				"(channel directions are different: '%s' != '%s').",
				param, input, param.ChanDir(), input.ChanDir())
		}
		return tp.unify(param.Elem(), input.Elem())
	case reflect.Func:
		if param.NumIn() != input.NumIn() || param.NumOut() != input.NumOut() {
			return tp.error("Cannot unify '%s' with '%s'.", param, input)
		}
		for i := 0; i < param.NumIn(); i++ {
			if err := tp.unify(param.In(i), input.In(i)); err != nil {
				return err
			}
		}
		for i := 0; i < param.NumOut(); i++ {
			if err := tp.unify(param.Out(i), input.Out(i)); err != nil {
				return err
			}
		}
	case reflect.Map:
		if err := tp.unify(param.Key(), input.Key()); err != nil {
			return err
		}
		return tp.unify(param.Elem(), input.Elem())
	case reflect.Ptr:
		return tp.unify(param.Elem(), input.Elem())
	case reflect.Slice:
		return tp.unify(param.Elem(), input.Elem())
	}

	// The only other container types are Interface and Struct.
	// I am unsure about what to do with interfaces. Mind is fuzzy.
	// Structs? I don't think it really makes much sense to use type
	// variables inside of them.
	return nil
}

// tysubst attempts to substitute all type variables within a single return
// type with their corresponding Go type from the type environment.
//
// tysubst will panic if a type variable is unbound, or if it encounters a
// type that cannot be dynamically created. Such types include arrays,
// functions and structs. (A limitation of the `reflect` package.)
func (rt returnType) tysubst(typ reflect.Type) reflect.Type {
	if tyname := tyvarName(typ); len(tyname) > 0 {
		if thetype, ok := rt.tyenv[tyname]; !ok {
			rt.panic("Unbound type variable %s.", tyname)
		} else {
			return thetype
		}
	}

	switch typ.Kind() {
	case reflect.Array:
		rt.panic("Cannot dynamically create Array types.")
	case reflect.Chan:
		return reflect.ChanOf(typ.ChanDir(), rt.tysubst(typ.Elem()))
	case reflect.Func:
		rt.panic("Cannot dynamically create Function types.")
	case reflect.Interface:
		rt.panic("TODO")
	case reflect.Map:
		return reflect.MapOf(rt.tysubst(typ.Key()), rt.tysubst(typ.Elem()))
	case reflect.Ptr:
		return reflect.PtrTo(rt.tysubst(typ.Elem()))
	case reflect.Slice:
		return reflect.SliceOf(rt.tysubst(typ.Elem()))
	case reflect.Struct:
		rt.panic("Cannot dynamically create Struct types.")
	case reflect.UnsafePointer:
		rt.panic("Cannot dynamically create unsafe.Pointer types.")
	}

	// We've covered all the composite types, so we're only left with
	// base types.
	return typ
}

func compileField(typ reflect.Type, name string, args []parse.Node, final reflect.Type) (fn lookupFn, elem reflect.Type) {
	if isNilType(typ) {
		fn = compileFieldDynamic(name, args)
		return
	}

	if m, exist := typ.MethodByName(name); exist {
		fn = compileMethodCall(typ, m.Func, args, final)
		elem = m.Type.Out(0)
		return
	}

	switch typ.Kind() {
	case reflect.Struct:
		structField, found := typ.FieldByName(name)
		if !found {
			panic(fmt.Errorf("%s has no field %s", typ, name))
		}
		fn = func(s state, v reflect.Value, final interface{}) reflect.Value {
			return v.FieldByIndex(structField.Index)
		}
		elem = structField.Type
		return
	case reflect.Map:
		k := reflect.ValueOf(name)
		fn = func(s state, v reflect.Value, final interface{}) reflect.Value {
			return v.MapIndex(k)
		}
		elem = typ.Key()
		return
	}
	panic(fmt.Errorf("struct or map expected, but got %s", typ))
}

func newMapEncoder(t reflect.Type) encoderFunc {
	if t.Key().Kind() != reflect.String {
		return unsupportedTypeEncoder
	}
	me := &mapEncoder{typeEncoder(t.Elem())}
	return me.encode
}