From 9e5b190585f2cc3cdb08c395ee1c30d460324afc Mon Sep 17 00:00:00 2001 From: RonniSkansing Date: Thu, 3 Sep 2026 00:26:24 +0200 Subject: [PATCH] refactor to use minor util for unwrapping errors Signed-off-by: RonniSkansing --- backend/utils/json.go | 3743 ++---------------------------------- backend/utils/json_test.go | 74 + 2 files changed, 243 insertions(+), 3574 deletions(-) create mode 100644 backend/utils/json_test.go diff --git a/backend/utils/json.go b/backend/utils/json.go index a70b600..897baf7 100644 --- a/backend/utils/json.go +++ b/backend/utils/json.go @@ -1,3639 +1,234 @@ -// 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 utils import ( "bytes" "encoding" - "encoding/base64" + "encoding/json" + "errors" "fmt" - "math" "reflect" - "slices" - "sort" - "strconv" "strings" - "sync" - "unicode" - "unicode/utf16" - "unicode/utf8" - - "github.com/phishingclub/phishingclub/errs" ) -// 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 [Unmarshaler], -// Unmarshal calls that value's [Unmarshaler.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 -// [encoding.TextUnmarshaler.UnmarshalText] 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 the JSON-encoded data contain a syntax error, Unmarshal returns a [SyntaxError]. -// -// 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. +var ( + unmarshalerType = reflect.TypeOf((*json.Unmarshaler)(nil)).Elem() + textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem() +) + +// Unmarshal decodes JSON with the standard library and, when a custom +// UnmarshalJSON method rejects a value, prefixes the error with the dotted +// JSON field path so the caller can tell which field was invalid. 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 { + err := json.Unmarshal(data, v) + if err == nil { + return nil + } + var syn *json.SyntaxError + if errors.As(err, &syn) { 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() + var typ *json.UnmarshalTypeError + if errors.As(err, &typ) { + return sanitizeTypeError(typ, nil) } - if e.Field != "" { - return "json: cannot unmarshal " + e.Value + " into Go struct field " + e.Field + " of type " + e.Type.String() + t, ok := targetType(v) + if !ok { + return err } - 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)" + path, located := locate(data, t) + if located == nil { + return err } - - if e.Type.Kind() != reflect.Pointer { - return "json: Unmarshal(non-pointer " + e.Type.String() + ")" + if errors.As(located, &typ) { + return sanitizeTypeError(typ, path) } - return "json: Unmarshal(nil " + e.Type.String() + ")" + if len(path) == 0 { + return located + } + return fmt.Errorf("%s: %v", strings.Join(path, "."), located) } -func (d *decodeState) unmarshal(v any) error { +// targetType unwraps pointers and interfaces to the concrete type being decoded into +func targetType(v any) (reflect.Type, bool) { 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, ".") - default: - if d.errorContext.FieldStack != nil { - field := strings.Join(d.errorContext.FieldStack, ".") - return fmt.Errorf("%s: %v", field, 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() 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 - } - - // Expand slice length, growing the slice if necessary. - if v.Kind() == reflect.Slice { - if i >= v.Cap() { - v.Grow(1) - } - 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 { - for ; i < v.Len(); i++ { - v.Index(i).SetZero() // zero remainder of array - } - } else { - v.SetLen(i) // truncate the slice - } - } - if i == 0 && v.Kind() == reflect.Slice { - v.Set(reflect.MakeSlice(v.Type(), 0, 0)) - } - return nil -} - -var nullLiteral = []byte("null") -var textUnmarshalerType = reflect.TypeFor[encoding.TextUnmarshaler]() - -// 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.SetZero() - } - subv = mapElem - } else { - f := fields.byExactName[string(key)] - if f == nil { - f = fields.byFoldedName[string(foldName(key))] - } - 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 - if reflect.PointerTo(kt).Implements(textUnmarshalerType) { - kv = reflect.New(kt) - if err := d.literalStore(item, kv, true); err != nil { - return err - } - kv = kv.Elem() - } else { - switch kt.Kind() { - case reflect.String: - kv = reflect.New(kt).Elem() - kv.SetString(string(key)) - 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.New(kt).Elem() - kv.SetInt(n) - 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.New(kt).Elem() - kv.SetUint(n) - 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.TypeFor[float64](), Offset: int64(d.off)} - } - return f, nil -} - -var numberType = reflect.TypeFor[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.SetZero() - // 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) - } - 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(string(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(string(item)) - 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(string(item), 10, 64) - if err != nil || v.OverflowInt(n) { - d.saveError(&UnmarshalTypeError{Value: "number " + string(item), 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(string(item), 10, 64) - if err != nil || v.OverflowUint(n) { - d.saveError(&UnmarshalTypeError{Value: "number " + string(item), Type: v.Type(), Offset: int64(d.readIndex())}) - break - } - v.SetUint(n) - - case reflect.Float32, reflect.Float64: - n, err := strconv.ParseFloat(string(item), v.Type().Bits()) - if err != nil || v.OverflowFloat(n) { - d.saveError(&UnmarshalTypeError{Value: "number " + string(item), 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 -} - -// Valid reports whether data is a valid JSON encoding. -func Valid(data []byte) bool { - scan := newScanner() - defer freeScanner(scan) - return checkValid(data, scan) == nil -} - -// checkValid verifies that data is valid JSON-encoded data. -// scan is passed in for use by checkValid to avoid an allocation. -// checkValid returns nil or a SyntaxError. -func checkValid(data []byte, scan *scanner) error { - scan.reset() - for _, c := range data { - scan.bytes++ - if scan.step(scan, c) == scanError { - return scan.err + for rv.IsValid() && (rv.Kind() == reflect.Pointer || rv.Kind() == reflect.Interface) { + if rv.IsNil() { + return nil, false } + rv = rv.Elem() } - if scan.eof() == scanError { - return scan.err - } - return nil -} - -// A SyntaxError is a description of a JSON syntax error. -// [Unmarshal] will return a SyntaxError if the JSON can't be parsed. -type SyntaxError struct { - msg string // description of error - Offset int64 // error occurred after reading Offset bytes -} - -func (e *SyntaxError) Error() string { return e.msg } - -// A scanner is a JSON scanning state machine. -// Callers call scan.reset and then pass bytes in one at a time -// by calling scan.step(&scan, c) for each byte. -// The return value, referred to as an opcode, tells the -// caller about significant parsing events like beginning -// and ending literals, objects, and arrays, so that the -// caller can follow along if it wishes. -// The return value scanEnd indicates that a single top-level -// JSON value has been completed, *before* the byte that -// just got passed in. (The indication must be delayed in order -// to recognize the end of numbers: is 123 a whole value or -// the beginning of 12345e+6?). -type scanner struct { - // The step is a func to be called to execute the next transition. - // Also tried using an integer constant and a single func - // with a switch, but using the func directly was 10% faster - // on a 64-bit Mac Mini, and it's nicer to read. - step func(*scanner, byte) int - - // Reached end of top-level value. - endTop bool - - // Stack of what we're in the middle of - array values, object keys, object values. - parseState []int - - // Error that happened, if any. - err error - - // total bytes consumed, updated by decoder.Decode (and deliberately - // not set to zero by scan.reset) - bytes int64 -} - -var scannerPool = sync.Pool{ - New: func() any { - return &scanner{} - }, -} - -func newScanner() *scanner { - scan := scannerPool.Get().(*scanner) - // scan.reset by design doesn't set bytes to zero - scan.bytes = 0 - scan.reset() - return scan -} - -func freeScanner(scan *scanner) { - // Avoid hanging on to too much memory in extreme cases. - if len(scan.parseState) > 1024 { - scan.parseState = nil - } - scannerPool.Put(scan) -} - -// These values are returned by the state transition functions -// assigned to scanner.state and the method scanner.eof. -// They give details about the current state of the scan that -// callers might be interested to know about. -// It is okay to ignore the return value of any particular -// call to scanner.state: if one call returns scanError, -// every subsequent call will return scanError too. -const ( - // Continue. - scanContinue = iota // uninteresting byte - scanBeginLiteral // end implied by next result != scanContinue - scanBeginObject // begin object - scanObjectKey // just finished object key (string) - scanObjectValue // just finished non-last object value - scanEndObject // end object (implies scanObjectValue if possible) - scanBeginArray // begin array - scanArrayValue // just finished array value - scanEndArray // end array (implies scanArrayValue if possible) - scanSkipSpace // space byte; can skip; known to be last "continue" result - - // Stop. - scanEnd // top-level value ended *before* this byte; known to be first "stop" result - scanError // hit an error, scanner.err. -) - -// These values are stored in the parseState stack. -// They give the current state of a composite value -// being scanned. If the parser is inside a nested value -// the parseState describes the nested state, outermost at entry 0. -const ( - parseObjectKey = iota // parsing object key (before colon) - parseObjectValue // parsing object value (after colon) - parseArrayValue // parsing array value -) - -// This limits the max nesting depth to prevent stack overflow. -// This is permitted by https://tools.ietf.org/html/rfc7159#section-9 -const maxNestingDepth = 10000 - -// reset prepares the scanner for use. -// It must be called before calling s.step. -func (s *scanner) reset() { - s.step = stateBeginValue - s.parseState = s.parseState[0:0] - s.err = nil - s.endTop = false -} - -// eof tells the scanner that the end of input has been reached. -// It returns a scan status just as s.step does. -func (s *scanner) eof() int { - if s.err != nil { - return scanError - } - if s.endTop { - return scanEnd - } - s.step(s, ' ') - if s.endTop { - return scanEnd - } - if s.err == nil { - s.err = &SyntaxError{"unexpected end of JSON input", s.bytes} - } - return scanError -} - -// pushParseState pushes a new parse state p onto the parse stack. -// an error state is returned if maxNestingDepth was exceeded, otherwise successState is returned. -func (s *scanner) pushParseState(c byte, newParseState int, successState int) int { - s.parseState = append(s.parseState, newParseState) - if len(s.parseState) <= maxNestingDepth { - return successState - } - return s.error(c, "exceeded max depth") -} - -// popParseState pops a parse state (already obtained) off the stack -// and updates s.step accordingly. -func (s *scanner) popParseState() { - n := len(s.parseState) - 1 - s.parseState = s.parseState[0:n] - if n == 0 { - s.step = stateEndTop - s.endTop = true - } else { - s.step = stateEndValue - } -} - -func isSpace(c byte) bool { - return c <= ' ' && (c == ' ' || c == '\t' || c == '\r' || c == '\n') -} - -// stateBeginValueOrEmpty is the state after reading `[`. -func stateBeginValueOrEmpty(s *scanner, c byte) int { - if isSpace(c) { - return scanSkipSpace - } - if c == ']' { - return stateEndValue(s, c) - } - return stateBeginValue(s, c) -} - -// stateBeginValue is the state at the beginning of the input. -func stateBeginValue(s *scanner, c byte) int { - if isSpace(c) { - return scanSkipSpace - } - switch c { - case '{': - s.step = stateBeginStringOrEmpty - return s.pushParseState(c, parseObjectKey, scanBeginObject) - case '[': - s.step = stateBeginValueOrEmpty - return s.pushParseState(c, parseArrayValue, scanBeginArray) - case '"': - s.step = stateInString - return scanBeginLiteral - case '-': - s.step = stateNeg - return scanBeginLiteral - case '0': // beginning of 0.123 - s.step = state0 - return scanBeginLiteral - case 't': // beginning of true - s.step = stateT - return scanBeginLiteral - case 'f': // beginning of false - s.step = stateF - return scanBeginLiteral - case 'n': // beginning of null - s.step = stateN - return scanBeginLiteral - } - if '1' <= c && c <= '9' { // beginning of 1234.5 - s.step = state1 - return scanBeginLiteral - } - return s.error(c, "looking for beginning of value") -} - -// stateBeginStringOrEmpty is the state after reading `{`. -func stateBeginStringOrEmpty(s *scanner, c byte) int { - if isSpace(c) { - return scanSkipSpace - } - if c == '}' { - n := len(s.parseState) - s.parseState[n-1] = parseObjectValue - return stateEndValue(s, c) - } - return stateBeginString(s, c) -} - -// stateBeginString is the state after reading `{"key": value,`. -func stateBeginString(s *scanner, c byte) int { - if isSpace(c) { - return scanSkipSpace - } - if c == '"' { - s.step = stateInString - return scanBeginLiteral + if !rv.IsValid() { + return nil, false } - return s.error(c, "looking for beginning of object key string") + return rv.Type(), true } -// stateEndValue is the state after completing a value, -// such as after reading `{}` or `true` or `["x"`. -func stateEndValue(s *scanner, c byte) int { - n := len(s.parseState) - if n == 0 { - // Completed top-level before the current byte. - s.step = stateEndTop - s.endTop = true - return stateEndTop(s, c) +// locate finds the first value in document order that fails to decode into t +// and returns the JSON field path leading to it +func locate(raw []byte, t reflect.Type) ([]string, error) { + if reflect.PointerTo(t).Implements(unmarshalerType) || t.Implements(unmarshalerType) { + return nil, json.Unmarshal(raw, reflect.New(t).Interface()) } - if isSpace(c) { - s.step = stateEndValue - return scanSkipSpace - } - ps := s.parseState[n-1] - switch ps { - case parseObjectKey: - if c == ':' { - s.parseState[n-1] = parseObjectValue - s.step = stateBeginValue - return scanObjectKey - } - return s.error(c, "after object key") - case parseObjectValue: - if c == ',' { - s.parseState[n-1] = parseObjectKey - s.step = stateBeginString - return scanObjectValue - } - if c == '}' { - s.popParseState() - return scanEndObject - } - return s.error(c, "after object key:value pair") - case parseArrayValue: - if c == ',' { - s.step = stateBeginValue - return scanArrayValue - } - if c == ']' { - s.popParseState() - return scanEndArray + if t.Kind() == reflect.Pointer { + if bytes.Equal(bytes.TrimSpace(raw), []byte("null")) { + return nil, nil } - return s.error(c, "after array element") - } - return s.error(c, "") -} - -// stateEndTop is the state after finishing the top-level value, -// such as after reading `{}` or `[1,2,3]`. -// Only space characters should be seen now. -func stateEndTop(s *scanner, c byte) int { - if !isSpace(c) { - // Complain about non-space byte on next call. - s.error(c, "after top-level value") - } - return scanEnd -} - -// stateInString is the state after reading `"`. -func stateInString(s *scanner, c byte) int { - if c == '"' { - s.step = stateEndValue - return scanContinue - } - if c == '\\' { - s.step = stateInStringEsc - return scanContinue - } - if c < 0x20 { - return s.error(c, "in string literal") - } - return scanContinue -} - -// stateInStringEsc is the state after reading `"\` during a quoted string. -func stateInStringEsc(s *scanner, c byte) int { - switch c { - case 'b', 'f', 'n', 'r', 't', '\\', '/', '"': - s.step = stateInString - return scanContinue - case 'u': - s.step = stateInStringEscU - return scanContinue - } - return s.error(c, "in string escape code") -} - -// stateInStringEscU is the state after reading `"\u` during a quoted string. -func stateInStringEscU(s *scanner, c byte) int { - if '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F' { - s.step = stateInStringEscU1 - return scanContinue - } - // numbers - return s.error(c, "in \\u hexadecimal character escape") -} - -// stateInStringEscU1 is the state after reading `"\u1` during a quoted string. -func stateInStringEscU1(s *scanner, c byte) int { - if '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F' { - s.step = stateInStringEscU12 - return scanContinue - } - // numbers - return s.error(c, "in \\u hexadecimal character escape") -} - -// stateInStringEscU12 is the state after reading `"\u12` during a quoted string. -func stateInStringEscU12(s *scanner, c byte) int { - if '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F' { - s.step = stateInStringEscU123 - return scanContinue - } - // numbers - return s.error(c, "in \\u hexadecimal character escape") -} - -// stateInStringEscU123 is the state after reading `"\u123` during a quoted string. -func stateInStringEscU123(s *scanner, c byte) int { - if '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F' { - s.step = stateInString - return scanContinue - } - // numbers - return s.error(c, "in \\u hexadecimal character escape") -} - -// stateNeg is the state after reading `-` during a number. -func stateNeg(s *scanner, c byte) int { - if c == '0' { - s.step = state0 - return scanContinue - } - if '1' <= c && c <= '9' { - s.step = state1 - return scanContinue - } - return s.error(c, "in numeric literal") -} - -// state1 is the state after reading a non-zero integer during a number, -// such as after reading `1` or `100` but not `0`. -func state1(s *scanner, c byte) int { - if '0' <= c && c <= '9' { - s.step = state1 - return scanContinue - } - return state0(s, c) -} - -// state0 is the state after reading `0` during a number. -func state0(s *scanner, c byte) int { - if c == '.' { - s.step = stateDot - return scanContinue - } - if c == 'e' || c == 'E' { - s.step = stateE - return scanContinue - } - return stateEndValue(s, c) -} - -// stateDot is the state after reading the integer and decimal point in a number, -// such as after reading `1.`. -func stateDot(s *scanner, c byte) int { - if '0' <= c && c <= '9' { - s.step = stateDot0 - return scanContinue - } - return s.error(c, "after decimal point in numeric literal") -} - -// stateDot0 is the state after reading the integer, decimal point, and subsequent -// digits of a number, such as after reading `3.14`. -func stateDot0(s *scanner, c byte) int { - if '0' <= c && c <= '9' { - return scanContinue - } - if c == 'e' || c == 'E' { - s.step = stateE - return scanContinue - } - return stateEndValue(s, c) -} - -// stateE is the state after reading the mantissa and e in a number, -// such as after reading `314e` or `0.314e`. -func stateE(s *scanner, c byte) int { - if c == '+' || c == '-' { - s.step = stateESign - return scanContinue + return locate(raw, t.Elem()) } - return stateESign(s, c) -} - -// stateESign is the state after reading the mantissa, e, and sign in a number, -// such as after reading `314e-` or `0.314e+`. -func stateESign(s *scanner, c byte) int { - if '0' <= c && c <= '9' { - s.step = stateE0 - return scanContinue - } - return s.error(c, "in exponent of numeric literal") -} - -// stateE0 is the state after reading the mantissa, e, optional sign, -// and at least one digit of the exponent in a number, -// such as after reading `314e-2` or `0.314e+1` or `3.14e0`. -func stateE0(s *scanner, c byte) int { - if '0' <= c && c <= '9' { - return scanContinue - } - return stateEndValue(s, c) -} - -// stateT is the state after reading `t`. -func stateT(s *scanner, c byte) int { - if c == 'r' { - s.step = stateTr - return scanContinue - } - return s.error(c, "in literal true (expecting 'r')") -} - -// stateTr is the state after reading `tr`. -func stateTr(s *scanner, c byte) int { - if c == 'u' { - s.step = stateTru - return scanContinue - } - return s.error(c, "in literal true (expecting 'u')") -} - -// stateTru is the state after reading `tru`. -func stateTru(s *scanner, c byte) int { - if c == 'e' { - s.step = stateEndValue - return scanContinue - } - return s.error(c, "in literal true (expecting 'e')") -} - -// stateF is the state after reading `f`. -func stateF(s *scanner, c byte) int { - if c == 'a' { - s.step = stateFa - return scanContinue - } - return s.error(c, "in literal false (expecting 'a')") -} - -// stateFa is the state after reading `fa`. -func stateFa(s *scanner, c byte) int { - if c == 'l' { - s.step = stateFal - return scanContinue - } - return s.error(c, "in literal false (expecting 'l')") -} - -// stateFal is the state after reading `fal`. -func stateFal(s *scanner, c byte) int { - if c == 's' { - s.step = stateFals - return scanContinue - } - return s.error(c, "in literal false (expecting 's')") -} - -// stateFals is the state after reading `fals`. -func stateFals(s *scanner, c byte) int { - if c == 'e' { - s.step = stateEndValue - return scanContinue - } - return s.error(c, "in literal false (expecting 'e')") -} - -// stateN is the state after reading `n`. -func stateN(s *scanner, c byte) int { - if c == 'u' { - s.step = stateNu - return scanContinue - } - return s.error(c, "in literal null (expecting 'u')") -} - -// stateNu is the state after reading `nu`. -func stateNu(s *scanner, c byte) int { - if c == 'l' { - s.step = stateNul - return scanContinue - } - return s.error(c, "in literal null (expecting 'l')") -} - -// stateNul is the state after reading `nul`. -func stateNul(s *scanner, c byte) int { - if c == 'l' { - s.step = stateEndValue - return scanContinue - } - return s.error(c, "in literal null (expecting 'l')") -} - -// stateError is the state after reaching a syntax error, -// such as after reading `[1}` or `5.1.2`. -func stateError(s *scanner, c byte) int { - return scanError -} - -// error records an error and switches to the error state. -func (s *scanner) error(c byte, context string) int { - s.step = stateError - s.err = &SyntaxError{"invalid character " + quoteChar(c) + " " + context, s.bytes} - return scanError -} - -// quoteChar formats c as a quoted character literal. -func quoteChar(c byte) string { - // special cases - different from quoted strings - if c == '\'' { - return `'\''` - } - if c == '"' { - return `'"'` - } - - // use quoted string with different quotation marks - s := strconv.Quote(string(c)) - return "'" + s[1:len(s)-1] + "'" -} - -// Marshal returns the JSON encoding of v. -// -// Marshal traverses the value v recursively. -// If an encountered value implements [Marshaler] -// and is not a nil pointer, Marshal calls [Marshaler.MarshalJSON] -// to produce JSON. If no [Marshaler.MarshalJSON] method is present but the -// value implements [encoding.TextMarshaler] instead, Marshal calls -// [encoding.TextMarshaler.MarshalText] and encodes the result as a JSON string. -// The nil pointer exception is not strictly necessary -// but mimics a similar, necessary exception in the behavior of -// [Unmarshaler.UnmarshalJSON]. -// -// Otherwise, Marshal uses the following type-dependent default encodings: -// -// Boolean values encode as JSON booleans. -// -// Floating point, integer, and [Number] values encode as JSON numbers. -// NaN and +/-Inf values will return an [UnsupportedValueError]. -// -// String values encode as JSON strings coerced to valid UTF-8, -// replacing invalid bytes with the Unicode replacement rune. -// So that the JSON will be safe to embed inside HTML