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Diffstat (limited to 'src/encoding/json/decode.go')
-rw-r--r-- | src/encoding/json/decode.go | 1310 |
1 files changed, 1310 insertions, 0 deletions
diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go new file mode 100644 index 0000000..555df0b --- /dev/null +++ b/src/encoding/json/decode.go @@ -0,0 +1,1310 @@ +// 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 any string type, an integer, implement json.Unmarshaler, 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 any) 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.Pointer { + return "json: Unmarshal(non-pointer " + e.Type.String() + ")" + } + return "json: Unmarshal(nil " + e.Type.String() + ")" +} + +func (d *decodeState) unmarshal(v any) error { + rv := reflect.ValueOf(v) + if rv.Kind() != reflect.Pointer || 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) +} + +// An errorContext provides context for type errors during decoding. +type errorContext struct { + Struct reflect.Type + FieldStack []string +} + +// 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 *errorContext + 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 + if d.errorContext != 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 != nil && (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 +} + +// 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() any { + 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 first settable 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.Pointer && 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.Pointer && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Pointer) { + haveAddr = false + v = e + continue + } + } + + if v.Kind() != reflect.Pointer { + break + } + + if 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.PointerTo(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 + var origErrorContext errorContext + if d.errorContext != nil { + 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.Pointer { + 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) + } + if d.errorContext == nil { + d.errorContext = new(errorContext) + } + 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 reflect.PointerTo(kt).Implements(textUnmarshalerType): + kv = reflect.New(kt) + if err := d.literalStore(item, kv, true); err != nil { + return err + } + kv = kv.Elem() + case kt.Kind() == reflect.String: + kv = reflect.ValueOf(key).Convert(kt) + 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) + } + if d.errorContext != nil { + // 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) (any, 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.Pointer, 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: + if v.Type() == numberType && !isValidNumber(string(s)) { + return fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", item) + } + 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 { + // s must be a valid number, because it's + // already been tokenized. + v.SetString(s) + 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 any) { + 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() []any { + var v = make([]any, 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]any { + m := make(map[string]any) + 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() any { + // 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 +} |