// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Represents JSON data structure using native Go types: booleans, floats,
// strings, arrays, and maps.
package json
import (
"encoding"
"encoding/base64"
"fmt"
"reflect"
"strconv"
"strings"
"unicode"
"unicode/utf16"
"unicode/utf8"
)
// Unmarshal parses the JSON-encoded data and stores the result
// in the value pointed to by v. If v is nil or not a pointer,
// Unmarshal returns an InvalidUnmarshalError.
//
// Unmarshal uses the inverse of the encodings that
// Marshal uses, allocating maps, slices, and pointers as necessary,
// with the following additional rules:
//
// To unmarshal JSON into a pointer, Unmarshal first handles the case of
// the JSON being the JSON literal null. In that case, Unmarshal sets
// the pointer to nil. Otherwise, Unmarshal unmarshals the JSON into
// the value pointed at by the pointer. If the pointer is nil, Unmarshal
// allocates a new value for it to point to.
//
// To unmarshal JSON into a value implementing the Unmarshaler interface,
// Unmarshal calls that value's UnmarshalJSON method, including
// when the input is a JSON null.
// Otherwise, if the value implements encoding.TextUnmarshaler
// and the input is a JSON quoted string, Unmarshal calls that value's
// UnmarshalText method with the unquoted form of the string.
//
// To unmarshal JSON into a struct, Unmarshal matches incoming object
// keys to the keys used by Marshal (either the struct field name or its tag),
// preferring an exact match but also accepting a case-insensitive match. By
// default, object keys which don't have a corresponding struct field are
// ignored (see Decoder.DisallowUnknownFields for an alternative).
//
// To unmarshal JSON into an interface value,
// Unmarshal stores one of these in the interface value:
//
// bool, for JSON booleans
// float64, for JSON numbers
// string, for JSON strings
// []interface{}, for JSON arrays
// map[string]interface{}, for JSON objects
// nil for JSON null
//
// To unmarshal a JSON array into a slice, Unmarshal resets the slice length
// to zero and then appends each element to the slice.
// As a special case, to unmarshal an empty JSON array into a slice,
// Unmarshal replaces the slice with a new empty slice.
//
// To unmarshal a JSON array into a Go array, Unmarshal decodes
// JSON array elements into corresponding Go array elements.
// If the Go array is smaller than the JSON array,
// the additional JSON array elements are discarded.
// If the JSON array is smaller than the Go array,
// the additional Go array elements are set to zero values.
//
// To unmarshal a JSON object into a map, Unmarshal first establishes a map to
// use. If the map is nil, Unmarshal allocates a new map. Otherwise Unmarshal
// reuses the existing map, keeping existing entries. Unmarshal then stores
// key-value pairs from the JSON object into the map. The map's key type must
// either be a string, an integer, or implement encoding.TextUnmarshaler.
//
// If a JSON value is not appropriate for a given target type,
// or if a JSON number overflows the target type, Unmarshal
// skips that field and completes the unmarshaling as best it can.
// If no more serious errors are encountered, Unmarshal returns
// an UnmarshalTypeError describing the earliest such error. In any
// case, it's not guaranteed that all the remaining fields following
// the problematic one will be unmarshaled into the target object.
//
// The JSON null value unmarshals into an interface, map, pointer, or slice
// by setting that Go value to nil. Because null is often used in JSON to mean
// ``not present,'' unmarshaling a JSON null into any other Go type has no effect
// on the value and produces no error.
//
// When unmarshaling quoted strings, invalid UTF-8 or
// invalid UTF-16 surrogate pairs are not treated as an error.
// Instead, they are replaced by the Unicode replacement
// character U+FFFD.
//
func Unmarshal(data []byte, v interface{}) error {
// Check for well-formedness.
// Avoids filling out half a data structure
// before discovering a JSON syntax error.
var d decodeState
err := checkValid(data, &d.scan)
if err != nil {
return err
}
d.init(data)
return d.unmarshal(v)
}
// Unmarshaler is the interface implemented by types
// that can unmarshal a JSON description of themselves.
// The input can be assumed to be a valid encoding of
// a JSON value. UnmarshalJSON must copy the JSON data
// if it wishes to retain the data after returning.
//
// By convention, to approximate the behavior of Unmarshal itself,
// Unmarshalers implement UnmarshalJSON([]byte("null")) as a no-op.
type Unmarshaler interface {
UnmarshalJSON([]byte) error
}
// An UnmarshalTypeError describes a JSON value that was
// not appropriate for a value of a specific Go type.
type UnmarshalTypeError struct {
Value string // description of JSON value - "bool", "array", "number -5"
Type reflect.Type // type of Go value it could not be assigned to
Offset int64 // error occurred after reading Offset bytes
Struct string // name of the struct type containing the field
Field string // the full path from root node to the field
}
func (e *UnmarshalTypeError) Error() string {
if e.Struct != "" || e.Field != "" {
return "json: cannot unmarshal " + e.Value + " into Go struct field " + e.Struct + "." + e.Field + " of type " + e.Type.String()
}
return "json: cannot unmarshal " + e.Value + " into Go value of type " + e.Type.String()
}
// An UnmarshalFieldError describes a JSON object key that
// led to an unexported (and therefore unwritable) struct field.
//
// Deprecated: No longer used; kept for compatibility.
type UnmarshalFieldError struct {
Key string
Type reflect.Type
Field reflect.StructField
}
func (e *UnmarshalFieldError) Error() string {
return "json: cannot unmarshal object key " + strconv.Quote(e.Key) + " into unexported field " + e.Field.Name + " of type " + e.Type.String()
}
// An InvalidUnmarshalError describes an invalid argument passed to Unmarshal.
// (The argument to Unmarshal must be a non-nil pointer.)
type InvalidUnmarshalError struct {
Type reflect.Type
}
func (e *InvalidUnmarshalError) Error() string {
if e.Type == nil {
return "json: Unmarshal(nil)"
}
if e.Type.Kind() != reflect.Ptr {
return "json: Unmarshal(non-pointer " + e.Type.String() + ")"
}
return "json: Unmarshal(nil " + e.Type.String() + ")"
}
func (d *decodeState) unmarshal(v interface{}) error {
rv := reflect.ValueOf(v)
if rv.Kind() != reflect.Ptr || rv.IsNil() {
return &InvalidUnmarshalError{reflect.TypeOf(v)}
}
d.scan.reset()
d.scanWhile(scanSkipSpace)
// We decode rv not rv.Elem because the Unmarshaler interface
// test must be applied at the top level of the value.
err := d.value(rv)
if err != nil {
return d.addErrorContext(err)
}
return d.savedError
}
// A Number represents a JSON number literal.
type Number string
// String returns the literal text of the number.
func (n Number) String() string { return string(n) }
// Float64 returns the number as a float64.
func (n Number) Float64() (float64, error) {
return strconv.ParseFloat(string(n), 64)
}
// Int64 returns the number as an int64.
func (n Number) Int64() (int64, error) {
return strconv.ParseInt(string(n), 10, 64)
}
// isValidNumber reports whether s is a valid JSON number literal.
func isValidNumber(s string) bool {
// This function implements the JSON numbers grammar.
// See https://tools.ietf.org/html/rfc7159#section-6
// and https://json.org/number.gif
if s == "" {
return false
}
// Optional -
if s[0] == '-' {
s = s[1:]
if s == "" {
return false
}
}
// Digits
switch {
default:
return false
case s[0] == '0':
s = s[1:]
case '1' <= s[0] && s[0] <= '9':
s = s[1:]
for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
s = s[1:]
}
}
// . followed by 1 or more digits.
if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' {
s = s[2:]
for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
s = s[1:]
}
}
// e or E followed by an optional - or + and
// 1 or more digits.
if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') {
s = s[1:]
if s[0] == '+' || s[0] == '-' {
s = s[1:]
if s == "" {
return false
}
}
for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
s = s[1:]
}
}
// Make sure we are at the end.
return s == ""
}
// decodeState represents the state while decoding a JSON value.
type decodeState struct {
data []byte
off int // next read offset in data
opcode int // last read result
scan scanner
errorContext struct { // provides context for type errors
Struct reflect.Type
FieldStack []string
}
savedError error
useNumber bool
disallowUnknownFields bool
}
// readIndex returns the position of the last byte read.
func (d *decodeState) readIndex() int {
return d.off - 1
}
// phasePanicMsg is used as a panic message when we end up with something that
// shouldn't happen. It can indicate a bug in the JSON decoder, or that
// something is editing the data slice while the decoder executes.
const phasePanicMsg = "JSON decoder out of sync - data changing underfoot?"
func (d *decodeState) init(data []byte) *decodeState {
d.data = data
d.off = 0
d.savedError = nil
d.errorContext.Struct = nil
// Reuse the allocated space for the FieldStack slice.
d.errorContext.FieldStack = d.errorContext.FieldStack[:0]
return d
}
// saveError saves the first err it is called with,
// for reporting at the end of the unmarshal.
func (d *decodeState) saveError(err error) {
if d.savedError == nil {
d.savedError = d.addErrorContext(err)
}
}
// addErrorContext returns a new error enhanced with information from d.errorContext
func (d *decodeState) addErrorContext(err error) error {
if d.errorContext.Struct != nil || len(d.errorContext.FieldStack) > 0 {
switch err := err.(type) {
case *UnmarshalTypeError:
err.Struct = d.errorContext.Struct.Name()
err.Field = strings.Join(d.errorContext.FieldStack, ".")
return err
}
}
return err
}
// skip scans to the end of what was started.
func (d *decodeState) skip() {
s, data, i := &d.scan, d.data, d.off
depth := len(s.parseState)
for {
op := s.step(s, data[i])
i++
if len(s.parseState) < depth {
d.off = i
d.opcode = op
return
}
}
}
// scanNext processes the byte at d.data[d.off].
func (d *decodeState) scanNext() {
if d.off < len(d.data) {
d.opcode = d.scan.step(&d.scan, d.data[d.off])
d.off++
} else {
d.opcode = d.scan.eof()
d.off = len(d.data) + 1 // mark processed EOF with len+1
}
}
// scanWhile processes bytes in d.data[d.off:] until it
// receives a scan code not equal to op.
func (d *decodeState) scanWhile(op int) {
s, data, i := &d.scan, d.data, d.off
for i < len(data) {
newOp := s.step(s, data[i])
i++
if newOp != op {
d.opcode = newOp
d.off = i
return
}
}
d.off = len(data) + 1 // mark processed EOF with len+1
d.opcode = d.scan.eof()
}
// rescanLiteral is similar to scanWhile(scanContinue), but it specialises the
// common case where we're decoding a literal. The decoder scans the input
// twice, once for syntax errors and to check the length of the value, and the
// second to perform the decoding.
//
// Only in the second step do we use decodeState to tokenize literals, so we
// know there aren't any syntax errors. We can take advantage of that knowledge,
// and scan a literal's bytes much more quickly.
func (d *decodeState) rescanLiteral() {
data, i := d.data, d.off
Switch:
switch data[i-1] {
case '"': // string
for ; i < len(data); i++ {
switch data[i] {
case '\\':
i++ // escaped char
case '"':
i++ // tokenize the closing quote too
break Switch
}
}
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-': // number
for ; i < len(data); i++ {
switch data[i] {
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'.', 'e', 'E', '+', '-':
default:
break Switch
}
}
case 't': // true
i += len("rue")
case 'f': // false
i += len("alse")
case 'n': // null
i += len("ull")
}
if i < len(data) {
d.opcode = stateEndValue(&d.scan, data[i])
} else {
d.opcode = scanEnd
}
d.off = i + 1
}
// value consumes a JSON value from d.data[d.off-1:], decoding into v, and
// reads the following byte ahead. If v is invalid, the value is discarded.
// The first byte of the value has been read already.
func (d *decodeState) value(v reflect.Value) error {
switch d.opcode {
default:
panic(phasePanicMsg)
case scanBeginArray:
if v.IsValid() {
if err := d.array(v); err != nil {
return err
}
} else {
d.skip()
}
d.scanNext()
case scanBeginObject:
if v.IsValid() {
if err := d.object(v); err != nil {
return err
}
} else {
d.skip()
}
d.scanNext()
case scanBeginLiteral:
// All bytes inside literal return scanContinue op code.
start := d.readIndex()
d.rescanLiteral()
if v.IsValid() {
if err := d.literalStore(d.data[start:d.readIndex()], v, false); err != nil {
return err
}
}
}
return nil
}
type unquotedValue struct{}
// valueQuoted is like value but decodes a
// quoted string literal or literal null into an interface value.
// If it finds anything other than a quoted string literal or null,
// valueQuoted returns unquotedValue{}.
func (d *decodeState) valueQuoted() interface{} {
switch d.opcode {
default:
panic(phasePanicMsg)
case scanBeginArray, scanBeginObject:
d.skip()
d.scanNext()
case scanBeginLiteral:
v := d.literalInterface()
switch v.(type) {
case nil, string:
return v
}
}
return unquotedValue{}
}
// indirect walks down v allocating pointers as needed,
// until it gets to a non-pointer.
// if it encounters an Unmarshaler, indirect stops and returns that.
// if decodingNull is true, indirect stops at the last pointer so it can be set to nil.
func indirect(v reflect.Value, decodingNull bool) (Unmarshaler, encoding.TextUnmarshaler, reflect.Value) {
// Issue #24153 indicates that it is generally not a guaranteed property
// that you may round-trip a reflect.Value by calling Value.Addr().Elem()
// and expect the value to still be settable for values derived from
// unexported embedded struct fields.
//
// The logic below effectively does this when it first addresses the value
// (to satisfy possible pointer methods) and continues to dereference
// subsequent pointers as necessary.
//
// After the first round-trip, we set v back to the original value to
// preserve the original RW flags contained in reflect.Value.
v0 := v
haveAddr := false
// If v is a named type and is addressable,
// start with its address, so that if the type has pointer methods,
// we find them.
if v.Kind() != reflect.Ptr && v.Type().Name() != "" && v.CanAddr() {
haveAddr = true
v = v.Addr()
}
for {
// Load value from interface, but only if the result will be
// usefully addressable.
if v.Kind() == reflect.Interface && !v.IsNil() {
e := v.Elem()
if e.Kind() == reflect.Ptr && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Ptr) {
haveAddr = false
v = e
continue
}
}
if v.Kind() != reflect.Ptr {
break
}
if v.Elem().Kind() != reflect.Ptr && decodingNull && v.CanSet() {
break
}
// Prevent infinite loop if v is an interface pointing to its own address:
// var v interface{}
// v = &v
if v.Elem().Kind() == reflect.Interface && v.Elem().Elem() == v {
v = v.Elem()
break
}
if v.IsNil() {
v.Set(reflect.New(v.Type().Elem()))
}
if v.Type().NumMethod() > 0 && v.CanInterface() {
if u, ok := v.Interface().(Unmarshaler); ok {
return u, nil, reflect.Value{}
}
if !decodingNull {
if u, ok := v.Interface().(encoding.TextUnmarshaler); ok {
return nil, u, reflect.Value{}
}
}
}
if haveAddr {
v = v0 // restore original value after round-trip Value.Addr().Elem()
haveAddr = false
} else {
v = v.Elem()
}
}
return nil, nil, v
}
// array consumes an array from d.data[d.off-1:], decoding into v.
// The first byte of the array ('[') has been read already.
func (d *decodeState) array(v reflect.Value) error {
// Check for unmarshaler.
u, ut, pv := indirect(v, false)
if u != nil {
start := d.readIndex()
d.skip()
return u.UnmarshalJSON(d.data[start:d.off])
}
if ut != nil {
d.saveError(&UnmarshalTypeError{Value: "array", Type: v.Type(), Offset: int64(d.off)})
d.skip()
return nil
}
v = pv
// Check type of target.
switch v.Kind() {
case reflect.Interface:
if v.NumMethod() == 0 {
// Decoding into nil interface? Switch to non-reflect code.
ai := d.arrayInterface()
v.Set(reflect.ValueOf(ai))
return nil
}
// Otherwise it's invalid.
fallthrough
default:
d.saveError(&UnmarshalTypeError{Value: "array", Type: v.Type(), Offset: int64(d.off)})
d.skip()
return nil
case reflect.Array, reflect.Slice:
break
}
i := 0
for {
// Look ahead for ] - can only happen on first iteration.
d.scanWhile(scanSkipSpace)
if d.opcode == scanEndArray {
break
}
// Get element of array, growing if necessary.
if v.Kind() == reflect.Slice {
// Grow slice if necessary
if i >= v.Cap() {
newcap := v.Cap() + v.Cap()/2
if newcap < 4 {
newcap = 4
}
newv := reflect.MakeSlice(v.Type(), v.Len(), newcap)
reflect.Copy(newv, v)
v.Set(newv)
}
if i >= v.Len() {
v.SetLen(i + 1)
}
}
if i < v.Len() {
// Decode into element.
if err := d.value(v.Index(i)); err != nil {
return err
}
} else {
// Ran out of fixed array: skip.
if err := d.value(reflect.Value{}); err != nil {
return err
}
}
i++
// Next token must be , or ].
if d.opcode == scanSkipSpace {
d.scanWhile(scanSkipSpace)
}
if d.opcode == scanEndArray {
break
}
if d.opcode != scanArrayValue {
panic(phasePanicMsg)
}
}
if i < v.Len() {
if v.Kind() == reflect.Array {
// Array. Zero the rest.
z := reflect.Zero(v.Type().Elem())
for ; i < v.Len(); i++ {
v.Index(i).Set(z)
}
} else {
v.SetLen(i)
}
}
if i == 0 && v.Kind() == reflect.Slice {
v.Set(reflect.MakeSlice(v.Type(), 0, 0))
}
return nil
}
var nullLiteral = []byte("null")
var textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
// object consumes an object from d.data[d.off-1:], decoding into v.
// The first byte ('{') of the object has been read already.
func (d *decodeState) object(v reflect.Value) error {
// Check for unmarshaler.
u, ut, pv := indirect(v, false)
if u != nil {
start := d.readIndex()
d.skip()
return u.UnmarshalJSON(d.data[start:d.off])
}
if ut != nil {
d.saveError(&UnmarshalTypeError{Value: "object", Type: v.Type(), Offset: int64(d.off)})
d.skip()
return nil
}
v = pv
t := v.Type()
// Decoding into nil interface? Switch to non-reflect code.
if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
oi := d.objectInterface()
v.Set(reflect.ValueOf(oi))
return nil
}
var fields structFields
// Check type of target:
// struct or
// map[T1]T2 where T1 is string, an integer type,
// or an encoding.TextUnmarshaler
switch v.Kind() {
case reflect.Map:
// Map key must either have string kind, have an integer kind,
// or be an encoding.TextUnmarshaler.
switch t.Key().Kind() {
case reflect.String,
reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
default:
if !reflect.PtrTo(t.Key()).Implements(textUnmarshalerType) {
d.saveError(&UnmarshalTypeError{Value: "object", Type: t, Offset: int64(d.off)})
d.skip()
return nil
}
}
if v.IsNil() {
v.Set(reflect.MakeMap(t))
}
case reflect.Struct:
fields = cachedTypeFields(t)
// ok
default:
d.saveError(&UnmarshalTypeError{Value: "object", Type: t, Offset: int64(d.off)})
d.skip()
return nil
}
var mapElem reflect.Value
origErrorContext := d.errorContext
for {
// Read opening " of string key or closing }.
d.scanWhile(scanSkipSpace)
if d.opcode == scanEndObject {
// closing } - can only happen on first iteration.
break
}
if d.opcode != scanBeginLiteral {
panic(phasePanicMsg)
}
// Read key.
start := d.readIndex()
d.rescanLiteral()
item := d.data[start:d.readIndex()]
key, ok := unquoteBytes(item)
if !ok {
panic(phasePanicMsg)
}
// Figure out field corresponding to key.
var subv reflect.Value
destring := false // whether the value is wrapped in a string to be decoded first
if v.Kind() == reflect.Map {
elemType := t.Elem()
if !mapElem.IsValid() {
mapElem = reflect.New(elemType).Elem()
} else {
mapElem.Set(reflect.Zero(elemType))
}
subv = mapElem
} else {
var f *field
if i, ok := fields.nameIndex[string(key)]; ok {
// Found an exact name match.
f = &fields.list[i]
} else {
// Fall back to the expensive case-insensitive
// linear search.
for i := range fields.list {
ff := &fields.list[i]
if ff.equalFold(ff.nameBytes, key) {
f = ff
break
}
}
}
if f != nil {
subv = v
destring = f.quoted
for _, i := range f.index {
if subv.Kind() == reflect.Ptr {
if subv.IsNil() {
// If a struct embeds a pointer to an unexported type,
// it is not possible to set a newly allocated value
// since the field is unexported.
//
// See https://golang.org/issue/21357
if !subv.CanSet() {
d.saveError(fmt.Errorf("json: cannot set embedded pointer to unexported struct: %v", subv.Type().Elem()))
// Invalidate subv to ensure d.value(subv) skips over
// the JSON value without assigning it to subv.
subv = reflect.Value{}
destring = false
break
}
subv.Set(reflect.New(subv.Type().Elem()))
}
subv = subv.Elem()
}
subv = subv.Field(i)
}
d.errorContext.FieldStack = append(d.errorContext.FieldStack, f.name)
d.errorContext.Struct = t
} else if d.disallowUnknownFields {
d.saveError(fmt.Errorf("json: unknown field %q", key))
}
}
// Read : before value.
if d.opcode == scanSkipSpace {
d.scanWhile(scanSkipSpace)
}
if d.opcode != scanObjectKey {
panic(phasePanicMsg)
}
d.scanWhile(scanSkipSpace)
if destring {
switch qv := d.valueQuoted().(type) {
case nil:
if err := d.literalStore(nullLiteral, subv, false); err != nil {
return err
}
case string:
if err := d.literalStore([]byte(qv), subv, true); err != nil {
return err
}
default:
d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal unquoted value into %v", subv.Type()))
}
} else {
if err := d.value(subv); err != nil {
return err
}
}
// Write value back to map;
// if using struct, subv points into struct already.
if v.Kind() == reflect.Map {
kt := t.Key()
var kv reflect.Value
switch {
case kt.Kind() == reflect.String:
kv = reflect.ValueOf(key).Convert(kt)
case reflect.PtrTo(kt).Implements(textUnmarshalerType):
kv = reflect.New(kt)
if err := d.literalStore(item, kv, true); err != nil {
return err
}
kv = kv.Elem()
default:
switch kt.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
s := string(key)
n, err := strconv.ParseInt(s, 10, 64)
if err != nil || reflect.Zero(kt).OverflowInt(n) {
d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: kt, Offset: int64(start + 1)})
break
}
kv = reflect.ValueOf(n).Convert(kt)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
s := string(key)
n, err := strconv.ParseUint(s, 10, 64)
if err != nil || reflect.Zero(kt).OverflowUint(n) {
d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: kt, Offset: int64(start + 1)})
break
}
kv = reflect.ValueOf(n).Convert(kt)
default:
panic("json: Unexpected key type") // should never occur
}
}
if kv.IsValid() {
v.SetMapIndex(kv, subv)
}
}
// Next token must be , or }.
if d.opcode == scanSkipSpace {
d.scanWhile(scanSkipSpace)
}
// Reset errorContext to its original state.
// Keep the same underlying array for FieldStack, to reuse the
// space and avoid unnecessary allocs.
d.errorContext.FieldStack = d.errorContext.FieldStack[:len(origErrorContext.FieldStack)]
d.errorContext.Struct = origErrorContext.Struct
if d.opcode == scanEndObject {
break
}
if d.opcode != scanObjectValue {
panic(phasePanicMsg)
}
}
return nil
}
// convertNumber converts the number literal s to a float64 or a Number
// depending on the setting of d.useNumber.
func (d *decodeState) convertNumber(s string) (interface{}, error) {
if d.useNumber {
return Number(s), nil
}
f, err := strconv.ParseFloat(s, 64)
if err != nil {
return nil, &UnmarshalTypeError{Value: "number " + s, Type: reflect.TypeOf(0.0), Offset: int64(d.off)}
}
return f, nil
}
var numberType = reflect.TypeOf(Number(""))
// literalStore decodes a literal stored in item into v.
//
// fromQuoted indicates whether this literal came from unwrapping a
// string from the ",string" struct tag option. this is used only to
// produce more helpful error messages.
func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool) error {
// Check for unmarshaler.
if len(item) == 0 {
//Empty string given
d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
return nil
}
isNull := item[0] == 'n' // null
u, ut, pv := indirect(v, isNull)
if u != nil {
return u.UnmarshalJSON(item)
}
if ut != nil {
if item[0] != '"' {
if fromQuoted {
d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
return nil
}
val := "number"
switch item[0] {
case 'n':
val = "null"
case 't', 'f':
val = "bool"
}
d.saveError(&UnmarshalTypeError{Value: val, Type: v.Type(), Offset: int64(d.readIndex())})
return nil
}
s, ok := unquoteBytes(item)
if !ok {
if fromQuoted {
return fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type())
}
panic(phasePanicMsg)
}
return ut.UnmarshalText(s)
}
v = pv
switch c := item[0]; c {
case 'n': // null
// The main parser checks that only true and false can reach here,
// but if this was a quoted string input, it could be anything.
if fromQuoted && string(item) != "null" {
d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
break
}
switch v.Kind() {
case reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
v.Set(reflect.Zero(v.Type()))
// otherwise, ignore null for primitives/string
}
case 't', 'f': // true, false
value := item[0] == 't'
// The main parser checks that only true and false can reach here,
// but if this was a quoted string input, it could be anything.
if fromQuoted && string(item) != "true" && string(item) != "false" {
d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
break
}
switch v.Kind() {
default:
if fromQuoted {
d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
} else {
d.saveError(&UnmarshalTypeError{Value: "bool", Type: v.Type(), Offset: int64(d.readIndex())})
}
case reflect.Bool:
v.SetBool(value)
case reflect.Interface:
if v.NumMethod() == 0 {
v.Set(reflect.ValueOf(value))
} else {
d.saveError(&UnmarshalTypeError{Value: "bool", Type: v.Type(), Offset: int64(d.readIndex())})
}
}
case '"': // string
s, ok := unquoteBytes(item)
if !ok {
if fromQuoted {
return fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type())
}
panic(phasePanicMsg)
}
switch v.Kind() {
default:
d.saveError(&UnmarshalTypeError{Value: "string", Type: v.Type(), Offset: int64(d.readIndex())})
case reflect.Slice:
if v.Type().Elem().Kind() != reflect.Uint8 {
d.saveError(&UnmarshalTypeError{Value: "string", Type: v.Type(), Offset: int64(d.readIndex())})
break
}
b := make([]byte, base64.StdEncoding.DecodedLen(len(s)))
n, err := base64.StdEncoding.Decode(b, s)
if err != nil {
d.saveError(err)
break
}
v.SetBytes(b[:n])
case reflect.String:
v.SetString(string(s))
case reflect.Interface:
if v.NumMethod() == 0 {
v.Set(reflect.ValueOf(string(s)))
} else {
d.saveError(&UnmarshalTypeError{Value: "string", Type: v.Type(), Offset: int64(d.readIndex())})
}
}
default: // number
if c != '-' && (c < '0' || c > '9') {
if fromQuoted {
return fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type())
}
panic(phasePanicMsg)
}
s := string(item)
switch v.Kind() {
default:
if v.Kind() == reflect.String && v.Type() == numberType {
v.SetString(s)
if !isValidNumber(s) {
return fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", item)
}
break
}
if fromQuoted {
return fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type())
}
d.saveError(&UnmarshalTypeError{Value: "number", Type: v.Type(), Offset: int64(d.readIndex())})
case reflect.Interface:
n, err := d.convertNumber(s)
if err != nil {
d.saveError(err)
break
}
if v.NumMethod() != 0 {
d.saveError(&UnmarshalTypeError{Value: "number", Type: v.Type(), Offset: int64(d.readIndex())})
break
}
v.Set(reflect.ValueOf(n))
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
n, err := strconv.ParseInt(s, 10, 64)
if err != nil || v.OverflowInt(n) {
d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: v.Type(), Offset: int64(d.readIndex())})
break
}
v.SetInt(n)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
n, err := strconv.ParseUint(s, 10, 64)
if err != nil || v.OverflowUint(n) {
d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: v.Type(), Offset: int64(d.readIndex())})
break
}
v.SetUint(n)
case reflect.Float32, reflect.Float64:
n, err := strconv.ParseFloat(s, v.Type().Bits())
if err != nil || v.OverflowFloat(n) {
d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: v.Type(), Offset: int64(d.readIndex())})
break
}
v.SetFloat(n)
}
}
return nil
}
// The xxxInterface routines build up a value to be stored
// in an empty interface. They are not strictly necessary,
// but they avoid the weight of reflection in this common case.
// valueInterface is like value but returns interface{}
func (d *decodeState) valueInterface() (val interface{}) {
switch d.opcode {
default:
panic(phasePanicMsg)
case scanBeginArray:
val = d.arrayInterface()
d.scanNext()
case scanBeginObject:
val = d.objectInterface()
d.scanNext()
case scanBeginLiteral:
val = d.literalInterface()
}
return
}
// arrayInterface is like array but returns []interface{}.
func (d *decodeState) arrayInterface() []interface{} {
var v = make([]interface{}, 0)
for {
// Look ahead for ] - can only happen on first iteration.
d.scanWhile(scanSkipSpace)
if d.opcode == scanEndArray {
break
}
v = append(v, d.valueInterface())
// Next token must be , or ].
if d.opcode == scanSkipSpace {
d.scanWhile(scanSkipSpace)
}
if d.opcode == scanEndArray {
break
}
if d.opcode != scanArrayValue {
panic(phasePanicMsg)
}
}
return v
}
// objectInterface is like object but returns map[string]interface{}.
func (d *decodeState) objectInterface() map[string]interface{} {
m := make(map[string]interface{})
for {
// Read opening " of string key or closing }.
d.scanWhile(scanSkipSpace)
if d.opcode == scanEndObject {
// closing } - can only happen on first iteration.
break
}
if d.opcode != scanBeginLiteral {
panic(phasePanicMsg)
}
// Read string key.
start := d.readIndex()
d.rescanLiteral()
item := d.data[start:d.readIndex()]
key, ok := unquote(item)
if !ok {
panic(phasePanicMsg)
}
// Read : before value.
if d.opcode == scanSkipSpace {
d.scanWhile(scanSkipSpace)
}
if d.opcode != scanObjectKey {
panic(phasePanicMsg)
}
d.scanWhile(scanSkipSpace)
// Read value.
m[key] = d.valueInterface()
// Next token must be , or }.
if d.opcode == scanSkipSpace {
d.scanWhile(scanSkipSpace)
}
if d.opcode == scanEndObject {
break
}
if d.opcode != scanObjectValue {
panic(phasePanicMsg)
}
}
return m
}
// literalInterface consumes and returns a literal from d.data[d.off-1:] and
// it reads the following byte ahead. The first byte of the literal has been
// read already (that's how the caller knows it's a literal).
func (d *decodeState) literalInterface() interface{} {
// All bytes inside literal return scanContinue op code.
start := d.readIndex()
d.rescanLiteral()
item := d.data[start:d.readIndex()]
switch c := item[0]; c {
case 'n': // null
return nil
case 't', 'f': // true, false
return c == 't'
case '"': // string
s, ok := unquote(item)
if !ok {
panic(phasePanicMsg)
}
return s
default: // number
if c != '-' && (c < '0' || c > '9') {
panic(phasePanicMsg)
}
n, err := d.convertNumber(string(item))
if err != nil {
d.saveError(err)
}
return n
}
}
// getu4 decodes \uXXXX from the beginning of s, returning the hex value,
// or it returns -1.
func getu4(s []byte) rune {
if len(s) < 6 || s[0] != '\\' || s[1] != 'u' {
return -1
}
var r rune
for _, c := range s[2:6] {
switch {
case '0' <= c && c <= '9':
c = c - '0'
case 'a' <= c && c <= 'f':
c = c - 'a' + 10
case 'A' <= c && c <= 'F':
c = c - 'A' + 10
default:
return -1
}
r = r*16 + rune(c)
}
return r
}
// unquote converts a quoted JSON string literal s into an actual string t.
// The rules are different than for Go, so cannot use strconv.Unquote.
func unquote(s []byte) (t string, ok bool) {
s, ok = unquoteBytes(s)
t = string(s)
return
}
func unquoteBytes(s []byte) (t []byte, ok bool) {
if len(s) < 2 || s[0] != '"' || s[len(s)-1] != '"' {
return
}
s = s[1 : len(s)-1]
// Check for unusual characters. If there are none,
// then no unquoting is needed, so return a slice of the
// original bytes.
r := 0
for r < len(s) {
c := s[r]
if c == '\\' || c == '"' || c < ' ' {
break
}
if c < utf8.RuneSelf {
r++
continue
}
rr, size := utf8.DecodeRune(s[r:])
if rr == utf8.RuneError && size == 1 {
break
}
r += size
}
if r == len(s) {
return s, true
}
b := make([]byte, len(s)+2*utf8.UTFMax)
w := copy(b, s[0:r])
for r < len(s) {
// Out of room? Can only happen if s is full of
// malformed UTF-8 and we're replacing each
// byte with RuneError.
if w >= len(b)-2*utf8.UTFMax {
nb := make([]byte, (len(b)+utf8.UTFMax)*2)
copy(nb, b[0:w])
b = nb
}
switch c := s[r]; {
case c == '\\':
r++
if r >= len(s) {
return
}
switch s[r] {
default:
return
case '"', '\\', '/', '\'':
b[w] = s[r]
r++
w++
case 'b':
b[w] = '\b'
r++
w++
case 'f':
b[w] = '\f'
r++
w++
case 'n':
b[w] = '\n'
r++
w++
case 'r':
b[w] = '\r'
r++
w++
case 't':
b[w] = '\t'
r++
w++
case 'u':
r--
rr := getu4(s[r:])
if rr < 0 {
return
}
r += 6
if utf16.IsSurrogate(rr) {
rr1 := getu4(s[r:])
if dec := utf16.DecodeRune(rr, rr1); dec != unicode.ReplacementChar {
// A valid pair; consume.
r += 6
w += utf8.EncodeRune(b[w:], dec)
break
}
// Invalid surrogate; fall back to replacement rune.
rr = unicode.ReplacementChar
}
w += utf8.EncodeRune(b[w:], rr)
}
// Quote, control characters are invalid.
case c == '"', c < ' ':
return
// ASCII
case c < utf8.RuneSelf:
b[w] = c
r++
w++
// Coerce to well-formed UTF-8.
default:
rr, size := utf8.DecodeRune(s[r:])
r += size
w += utf8.EncodeRune(b[w:], rr)
}
}
return b[0:w], true
}
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