otto/value.go

package otto

import (
	"fmt"
	"math"
	"reflect"
	"strconv"
	"unicode/utf16"
)

type _valueType int

const (
	valueEmpty _valueType = iota
	valueNull
	valueUndefined
	valueNumber
	valueString
	valueBoolean
	valueObject
	valueResult
	valueReference
)

// Value is the representation of a JavaScript value.
type Value struct {
	_valueType
	value interface{}
}

// ToValue will convert an interface{} value to a value digestible by otto/JavaScript
// This function will not work for advanced types (struct, map, slice/array, etc.) and
// you probably should not use it.
//
// ToValue may be deprecated and removed in the near future.
//
// Try Otto.ToValue for a replacement.
func ToValue(value interface{}) (Value, error) {
	result := UndefinedValue()
	err := catchPanic(func() {
		result = toValue(value)
	})
	return result, err
}

// Empty

func emptyValue() Value {
	return Value{_valueType: valueEmpty}
}

func (value Value) isEmpty() bool {
	return value._valueType == valueEmpty
}

// Undefined

// UndefinedValue will return a Value representing undefined.
func UndefinedValue() Value {
	return Value{_valueType: valueUndefined}
}

// IsDefined will return false if the value is undefined, and true otherwise.
func (value Value) IsDefined() bool {
	return value._valueType != valueUndefined
}

// IsUndefined will return true if the value is undefined, and false otherwise.
func (value Value) IsUndefined() bool {
	return value._valueType == valueUndefined
}

// NullValue will return a Value representing null.
func NullValue() Value {
	return Value{_valueType: valueNull}
}

// IsNull will return true if the value is null, and false otherwise.
func (value Value) IsNull() bool {
	return value._valueType == valueNull
}

// ---

func (value Value) isCallable() bool {
	switch value := value.value.(type) {
	case *_object:
		return value.functionValue().call != nil
	}
	return false
}

func (value Value) isResult() bool {
	return value._valueType == valueResult
}

func (value Value) isReference() bool {
	return value._valueType == valueReference
}

// Call the value as a function with the given this value and argument list and
// return the result of invocation. It is essentially equivalent to:
//
//		value.apply(thisValue, argumentList)
//
// An undefined value and an error will result if:
//
//		1. There is an error during conversion of the argument list
//		2. The value is not actually a function
//		3. An (uncaught) exception is thrown
//
func (value Value) Call(this Value, argumentList ...interface{}) (Value, error) {
	result := UndefinedValue()
	err := catchPanic(func() {
		result = value.call(this, argumentList...)
	})
	return result, err
}

func (value Value) call(this Value, argumentList ...interface{}) Value {
	switch function := value.value.(type) {
	case *_object:
		return function.Call(this, argumentList...)
	}
	panic(newTypeError())
}

func (value Value) constructSafe(this Value, argumentList ...interface{}) (Value, error) {
	result := UndefinedValue()
	err := catchPanic(func() {
		result = value.construct(this, argumentList...)
	})
	return result, err
}

func (value Value) construct(this Value, argumentList ...interface{}) Value {
	switch function := value.value.(type) {
	case *_object:
		return function.Construct(this, argumentList...)
	}
	panic(newTypeError())
}

// IsPrimitive will return true if value is a primitive (any kind of primitive).
func (value Value) IsPrimitive() bool {
	return !value.IsObject()
}

// IsBoolean will return true if value is a boolean (primitive).
func (value Value) IsBoolean() bool {
	return value._valueType == valueBoolean
}

// IsNumber will return true if value is a number (primitive).
func (value Value) IsNumber() bool {
	return value._valueType == valueNumber
}

// IsNaN will return true if value is NaN (or would convert to NaN).
func (value Value) IsNaN() bool {
	switch value := value.value.(type) {
	case float64:
		return math.IsNaN(value)
	case float32:
		return math.IsNaN(float64(value))
	case int, int8, int32, int64:
		return false
	case uint, uint8, uint32, uint64:
		return false
	}

	return math.IsNaN(toFloat(value))
}

// IsString will return true if value is a string (primitive).
func (value Value) IsString() bool {
	return value._valueType == valueString
}

// IsObject will return true if value is an object.
func (value Value) IsObject() bool {
	return value._valueType == valueObject
}

// IsFunction will return true if value is a function.
func (value Value) IsFunction() bool {
	if value._valueType != valueObject {
		return false
	}
	return value.value.(*_object).class == "Function"
}

// Class will return the class string of the value or the empty string if value is not an object.
//
// The return value will (generally) be one of:
//
//		Object
//		Function
//		Array
//		String
//		Number
//		Boolean
//		Date
//		RegExp
//
func (value Value) Class() string {
	if value._valueType != valueObject {
		return ""
	}
	return value.value.(*_object).class
}

func (value Value) isArray() bool {
	if value._valueType != valueObject {
		return false
	}
	return value.value.(*_object).class == "Array"
}

func (value Value) isStringObject() bool {
	if value._valueType != valueObject {
		return false
	}
	return value.value.(*_object).class == "String"
}

func (value Value) isBooleanObject() bool {
	if value._valueType != valueObject {
		return false
	}
	return value.value.(*_object).class == "Boolean"
}

func (value Value) isNumberObject() bool {
	if value._valueType != valueObject {
		return false
	}
	return value.value.(*_object).class == "Number"
}

func (value Value) isDate() bool {
	if value._valueType != valueObject {
		return false
	}
	return value.value.(*_object).class == "Date"
}

func (value Value) isRegExp() bool {
	if value._valueType != valueObject {
		return false
	}
	return value.value.(*_object).class == "RegExp"
}

func (value Value) isError() bool {
	if value._valueType != valueObject {
		return false
	}
	return value.value.(*_object).class == "Error"
}

// ---

func toValue_reflectValuePanic(value interface{}, kind reflect.Kind) {
	switch kind {
	case reflect.Struct:
		panic(newTypeError("Invalid value (struct): Missing runtime: %v (%T)", value, value))
	case reflect.Map:
		panic(newTypeError("Invalid value (map): Missing runtime: %v (%T)", value, value))
	case reflect.Slice:
		panic(newTypeError("Invalid value (slice): Missing runtime: %v (%T)", value, value))
	}
}

func toValue(value interface{}) Value {
	switch value := value.(type) {
	case Value:
		return value
	case bool:
		return Value{valueBoolean, value}
	case int:
		return Value{valueNumber, value}
	case int8:
		return Value{valueNumber, value}
	case int16:
		return Value{valueNumber, value}
	case int32:
		return Value{valueNumber, value}
	case int64:
		return Value{valueNumber, value}
	case uint:
		return Value{valueNumber, value}
	case uint8:
		return Value{valueNumber, value}
	case uint16:
		return Value{valueNumber, value}
	case uint32:
		return Value{valueNumber, value}
	case uint64:
		return Value{valueNumber, value}
	case float32:
		return Value{valueNumber, float64(value)}
	case float64:
		return Value{valueNumber, value}
	case []uint16:
		return Value{valueString, value}
	case string:
		return Value{valueString, value}
	// A rune is actually an int32, which is handled above
	case *_object:
		return Value{valueObject, value}
	case *Object:
		return Value{valueObject, value.object}
	case Object:
		return Value{valueObject, value.object}
	case _reference: // reference is an interface (already a pointer)
		return Value{valueReference, value}
	case _result:
		return Value{valueResult, value}
	case nil:
		// TODO Ugh.
		return UndefinedValue()
	case reflect.Value:
		value = reflect.Indirect(value)
		switch value.Kind() {
		case reflect.Bool:
			return Value{valueBoolean, bool(value.Bool())}
		case reflect.Int:
			return Value{valueNumber, int(value.Int())}
		case reflect.Int8:
			return Value{valueNumber, int8(value.Int())}
		case reflect.Int16:
			return Value{valueNumber, int16(value.Int())}
		case reflect.Int32:
			return Value{valueNumber, int32(value.Int())}
		case reflect.Int64:
			return Value{valueNumber, int64(value.Int())}
		case reflect.Uint:
			return Value{valueNumber, uint(value.Uint())}
		case reflect.Uint8:
			return Value{valueNumber, uint8(value.Uint())}
		case reflect.Uint16:
			return Value{valueNumber, uint16(value.Uint())}
		case reflect.Uint32:
			return Value{valueNumber, uint32(value.Uint())}
		case reflect.Uint64:
			return Value{valueNumber, uint64(value.Uint())}
		case reflect.Float32:
			return Value{valueNumber, float32(value.Float())}
		case reflect.Float64:
			return Value{valueNumber, float64(value.Float())}
		case reflect.String:
			return Value{valueString, string(value.String())}
		default:
			toValue_reflectValuePanic(value.Interface(), value.Kind())
		}
	default:
		{
			value := reflect.ValueOf(value)
			if value.IsNil() {
				return UndefinedValue()
			}

			value = reflect.Indirect(value)
			toValue_reflectValuePanic(value.Interface(), value.Kind())
		}
	}
	panic(newTypeError("Invalid value: Unsupported: %v (%T)", value, value))
}

// String will return the value as a string.
//
// This method will make return the empty string if there is an error.
func (value Value) String() string {
	result := ""
	catchPanic(func() {
		result = value.toString()
	})
	return result
}

func (value Value) toBoolean() bool {
	return toBoolean(value)
}

func (value Value) isTrue() bool {
	return toBoolean(value)
}

// ToBoolean will convert the value to a boolean (bool).
//
//		ToValue(0).ToBoolean() => false
//		ToValue("").ToBoolean() => false
//		ToValue(true).ToBoolean() => true
//		ToValue(1).ToBoolean() => true
//		ToValue("Nothing happens").ToBoolean() => true
//
// If there is an error during the conversion process (like an uncaught exception), then the result will be false and an error.
func (value Value) ToBoolean() (bool, error) {
	result := false
	err := catchPanic(func() {
		result = toBoolean(value)
	})
	return result, err
}

func (value Value) toNumber() Value {
	return toNumber(value)
}

func (value Value) toFloat() float64 {
	return toFloat(value)
}

// ToFloat will convert the value to a number (float64).
//
//		ToValue(0).ToFloat() => 0.
//		ToValue(1.1).ToFloat() => 1.1
//		ToValue("11").ToFloat() => 11.
//
// If there is an error during the conversion process (like an uncaught exception), then the result will be 0 and an error.
func (value Value) ToFloat() (float64, error) {
	result := float64(0)
	err := catchPanic(func() {
		result = toFloat(value)
	})
	return result, err
}

// ToInteger will convert the value to a number (int64).
//
//		ToValue(0).ToInteger() => 0
//		ToValue(1.1).ToInteger() => 1
//		ToValue("11").ToInteger() => 11
//
// If there is an error during the conversion process (like an uncaught exception), then the result will be 0 and an error.
func (value Value) ToInteger() (int64, error) {
	result := int64(0)
	err := catchPanic(func() {
		result = toInteger(value).value
	})
	return result, err
}

func (value Value) toString() string {
	return toString(value)
}

// ToString will convert the value to a string (string).
//
//		ToValue(0).ToString() => "0"
//		ToValue(false).ToString() => "false"
//		ToValue(1.1).ToString() => "1.1"
//		ToValue("11").ToString() => "11"
//		ToValue('Nothing happens.').ToString() => "Nothing happens."
//
// If there is an error during the conversion process (like an uncaught exception), then the result will be the empty string ("") and an error.
func (value Value) ToString() (string, error) {
	result := ""
	err := catchPanic(func() {
		result = toString(value)
	})
	return result, err
}

func (value Value) _object() *_object {
	switch value := value.value.(type) {
	case *_object:
		return value
	}
	return nil
}

// Object will return the object of the value, or nil if value is not an object.
//
// This method will not do any implicit conversion. For example, calling this method on a string primitive value will not return a String object.
func (value Value) Object() *Object {
	switch object := value.value.(type) {
	case *_object:
		return _newObject(object, value)
	}
	return nil
}

func (value Value) reference() _reference {
	switch value := value.value.(type) {
	case _reference:
		return value
	}
	return nil
}

var (
	__NaN__              float64 = math.NaN()
	__PositiveInfinity__ float64 = math.Inf(+1)
	__NegativeInfinity__ float64 = math.Inf(-1)
	__PositiveZero__     float64 = 0
	__NegativeZero__     float64 = math.Float64frombits(0 | (1 << 63))
)

func positiveInfinity() float64 {
	return __PositiveInfinity__
}

func negativeInfinity() float64 {
	return __NegativeInfinity__
}

func positiveZero() float64 {
	return __PositiveZero__
}

func negativeZero() float64 {
	return __NegativeZero__
}

// NaNValue will return a value representing NaN.
//
// It is equivalent to:
//
//		ToValue(math.NaN())
//
func NaNValue() Value {
	return Value{valueNumber, __NaN__}
}

func positiveInfinityValue() Value {
	return Value{valueNumber, __PositiveInfinity__}
}

func negativeInfinityValue() Value {
	return Value{valueNumber, __NegativeInfinity__}
}

func positiveZeroValue() Value {
	return Value{valueNumber, __PositiveZero__}
}

func negativeZeroValue() Value {
	return Value{valueNumber, __NegativeZero__}
}

// TrueValue will return a value representing true.
//
// It is equivalent to:
//
//		ToValue(true)
//
func TrueValue() Value {
	return Value{valueBoolean, true}
}

// FalseValue will return a value representing false.
//
// It is equivalent to:
//
//		ToValue(false)
//
func FalseValue() Value {
	return Value{valueBoolean, false}
}

func sameValue(x Value, y Value) bool {
	if x._valueType != y._valueType {
		return false
	}
	result := false
	switch x._valueType {
	case valueUndefined, valueNull:
		result = true
	case valueNumber:
		x := x.toFloat()
		y := y.toFloat()
		if math.IsNaN(x) && math.IsNaN(y) {
			result = true
		} else {
			result = x == y
			if result && x == 0 {
				// Since +0 != -0
				result = math.Signbit(x) == math.Signbit(y)
			}
		}
	case valueString:
		result = x.toString() == y.toString()
	case valueBoolean:
		result = x.toBoolean() == y.toBoolean()
	case valueObject:
		result = x._object() == y._object()
	default:
		panic(hereBeDragons())
	}

	return result
}

// Export will attempt to convert the value to a Go representation
// and return it via an interface{} kind.
//
// WARNING: The interface function will be changing soon to:
//
//      Export() interface{}
//
// If a reasonable conversion is not possible, then the original
// result is returned.
//
//      undefined   -> otto.Value (UndefinedValue())
//      null        -> interface{}(nil)
//      boolean     -> bool
//      number      -> A number type (int, float32, uint64, ...)
//      string      -> string
//      Array       -> []interface{}
//      Object      -> map[string]interface{}
//
func (self Value) Export() (interface{}, error) {
	return self.export(), nil
}

func (self Value) export() interface{} {

	switch self._valueType {
	case valueUndefined:
		return nil
	case valueNull:
		return nil
	case valueNumber, valueBoolean:
		return self.value
	case valueString:
		switch value := self.value.(type) {
		case string:
			return value
		case []uint16:
			return string(utf16.Decode(value))
		}
	case valueObject:
		object := self._object()
		switch value := object.value.(type) {
		case *_goStructObject:
			return value.value.Interface()
		case *_goMapObject:
			return value.value.Interface()
		case *_goArrayObject:
			return value.value.Interface()
		case *_goSliceObject:
			return value.value.Interface()
		}
		if object.class == "Array" {
			result := make([]interface{}, 0)
			lengthValue := object.get("length")
			length := lengthValue.value.(uint32)
			for index := uint32(0); index < length; index += 1 {
				name := strconv.FormatInt(int64(index), 10)
				if !object.hasProperty(name) {
					continue
				}
				value := object.get(name)
				result = append(result, value.export())
			}
			return result
		} else {
			result := make(map[string]interface{})
			// TODO Should we export everything? Or just what is enumerable?
			object.enumerate(false, func(name string) bool {
				value := object.get(name)
				if value.IsDefined() {
					result[name] = value.export()
				}
				return true
			})
			return result
		}
	}

	return self
}

func (self Value) evaluateBreakContinue(labelSet _labelSet) _resultKind {
	if result, valid := self.value.(_result); valid {
		switch result.kind {
		case resultBreak, resultContinue:
			if labelSet[result.target] {
				return result.kind
			}
		}
		return resultReturn
	}
	return resultNormal
}

func (self Value) evaluateBreak(labelSet _labelSet) _resultKind {
	if result, valid := self.value.(_result); valid {
		switch result.kind {
		case resultBreak:
			if labelSet[result.target] {
				return result.kind
			}
		}
		return resultReturn
	}
	return resultNormal
}

func (self Value) exportNative() interface{} {

	switch self._valueType {
	case valueUndefined:
		return self
	case valueNull:
		return nil
	case valueNumber, valueBoolean:
		return self.value
	case valueString:
		switch value := self.value.(type) {
		case string:
			return value
		case []uint16:
			return string(utf16.Decode(value))
		}
	case valueObject:
		object := self._object()
		switch value := object.value.(type) {
		case *_goStructObject:
			return value.value.Interface()
		case *_goMapObject:
			return value.value.Interface()
		case *_goArrayObject:
			return value.value.Interface()
		case *_goSliceObject:
			return value.value.Interface()
		}
	}

	return self
}

func (value Value) toReflectValue(kind reflect.Kind) (reflect.Value, error) {
	switch kind {
	case reflect.Bool:
		return reflect.ValueOf(value.toBoolean()), nil
	case reflect.Int:
		// We convert to float64 here because converting to int64 will not tell us
		// if a value is outside the range of int64
		tmp := toIntegerFloat(value)
		if tmp < float_minInt || tmp > float_maxInt {
			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to int", tmp, value)
		} else {
			return reflect.ValueOf(int(tmp)), nil
		}
	case reflect.Int8:
		tmp := toInteger(value).value
		if tmp < int64_minInt8 || tmp > int64_maxInt8 {
			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to int8", tmp, value)
		} else {
			return reflect.ValueOf(int8(tmp)), nil
		}
	case reflect.Int16:
		tmp := toInteger(value).value
		if tmp < int64_minInt16 || tmp > int64_maxInt16 {
			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to int16", tmp, value)
		} else {
			return reflect.ValueOf(int16(tmp)), nil
		}
	case reflect.Int32:
		tmp := toInteger(value).value
		if tmp < int64_minInt32 || tmp > int64_maxInt32 {
			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to int32", tmp, value)
		} else {
			return reflect.ValueOf(int32(tmp)), nil
		}
	case reflect.Int64:
		// We convert to float64 here because converting to int64 will not tell us
		// if a value is outside the range of int64
		tmp := toIntegerFloat(value)
		if tmp < float_minInt64 || tmp > float_maxInt64 {
			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to int", tmp, value)
		} else {
			return reflect.ValueOf(int64(tmp)), nil
		}
	case reflect.Uint:
		// We convert to float64 here because converting to int64 will not tell us
		// if a value is outside the range of uint
		tmp := toIntegerFloat(value)
		if tmp < 0 || tmp > float_maxUint {
			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to uint", tmp, value)
		} else {
			return reflect.ValueOf(uint(tmp)), nil
		}
	case reflect.Uint8:
		tmp := toInteger(value).value
		if tmp < 0 || tmp > int64_maxUint8 {
			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to uint8", tmp, value)
		} else {
			return reflect.ValueOf(uint8(tmp)), nil
		}
	case reflect.Uint16:
		tmp := toInteger(value).value
		if tmp < 0 || tmp > int64_maxUint16 {
			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to uint16", tmp, value)
		} else {
			return reflect.ValueOf(uint16(tmp)), nil
		}
	case reflect.Uint32:
		tmp := toInteger(value).value
		if tmp < 0 || tmp > int64_maxUint32 {
			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to uint32", tmp, value)
		} else {
			return reflect.ValueOf(uint32(tmp)), nil
		}
	case reflect.Uint64:
		// We convert to float64 here because converting to int64 will not tell us
		// if a value is outside the range of uint64
		tmp := toIntegerFloat(value)
		if tmp < 0 || tmp > float_maxUint64 {
			return reflect.Value{}, fmt.Errorf("RangeError: %f (%v) to uint64", tmp, value)
		} else {
			return reflect.ValueOf(uint64(tmp)), nil
		}
	case reflect.Float32:
		tmp := toFloat(value)
		tmp1 := tmp
		if 0 > tmp1 {
			tmp1 = -tmp1
		}
		if tmp1 < math.SmallestNonzeroFloat32 || tmp1 > math.MaxFloat32 {
			return reflect.Value{}, fmt.Errorf("RangeError: %f (%v) to float32", tmp, value)
		} else {
			return reflect.ValueOf(float32(tmp)), nil
		}
	case reflect.Float64:
		value := toFloat(value)
		return reflect.ValueOf(float64(value)), nil
	case reflect.String:
		return reflect.ValueOf(value.toString()), nil
	case reflect.Interface:
		return reflect.ValueOf(value.exportNative()), nil
	}

	dbgf("%/panic//%@: Invalid: (%v) to reflect.Kind: %v", value, kind)
	panic("")
}

func stringToReflectValue(value string, kind reflect.Kind) (reflect.Value, error) {
	switch kind {
	case reflect.Bool:
		value, err := strconv.ParseBool(value)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(value), nil
	case reflect.Int:
		value, err := strconv.ParseInt(value, 0, 0)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(int(value)), nil
	case reflect.Int8:
		value, err := strconv.ParseInt(value, 0, 8)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(int8(value)), nil
	case reflect.Int16:
		value, err := strconv.ParseInt(value, 0, 16)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(int16(value)), nil
	case reflect.Int32:
		value, err := strconv.ParseInt(value, 0, 32)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(int32(value)), nil
	case reflect.Int64:
		value, err := strconv.ParseInt(value, 0, 64)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(int64(value)), nil
	case reflect.Uint:
		value, err := strconv.ParseUint(value, 0, 0)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(uint(value)), nil
	case reflect.Uint8:
		value, err := strconv.ParseUint(value, 0, 8)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(uint8(value)), nil
	case reflect.Uint16:
		value, err := strconv.ParseUint(value, 0, 16)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(uint16(value)), nil
	case reflect.Uint32:
		value, err := strconv.ParseUint(value, 0, 32)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(uint32(value)), nil
	case reflect.Uint64:
		value, err := strconv.ParseUint(value, 0, 64)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(uint64(value)), nil
	case reflect.Float32:
		value, err := strconv.ParseFloat(value, 32)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(float32(value)), nil
	case reflect.Float64:
		value, err := strconv.ParseFloat(value, 64)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(float64(value)), nil
	case reflect.String:
		return reflect.ValueOf(value), nil
	}

	dbgf("%/panic//%@: Invalid: \"%s\" to reflect.Kind: %v", value, kind)
	panic("")
}