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-rw-r--r--src/encoding/json/encode.go1418
1 files changed, 1418 insertions, 0 deletions
diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go
new file mode 100644
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--- /dev/null
+++ b/src/encoding/json/encode.go
@@ -0,0 +1,1418 @@
+// 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.
+
+// Package json implements encoding and decoding of JSON as defined in
+// RFC 7159. The mapping between JSON and Go values is described
+// in the documentation for the Marshal and Unmarshal functions.
+//
+// See "JSON and Go" for an introduction to this package:
+// https://golang.org/doc/articles/json_and_go.html
+package json
+
+import (
+ "bytes"
+ "encoding"
+ "encoding/base64"
+ "fmt"
+ "math"
+ "reflect"
+ "sort"
+ "strconv"
+ "strings"
+ "sync"
+ "unicode"
+ "unicode/utf8"
+)
+
+// Marshal returns the JSON encoding of v.
+//
+// Marshal traverses the value v recursively.
+// If an encountered value implements the Marshaler interface
+// and is not a nil pointer, Marshal calls its MarshalJSON method
+// to produce JSON. If no MarshalJSON method is present but the
+// value implements encoding.TextMarshaler instead, Marshal calls
+// its MarshalText method 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
+// 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.
+//
+// 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 <script> tags,
+// the string is encoded using HTMLEscape,
+// which replaces "<", ">", "&", U+2028, and U+2029 are escaped
+// to "\u003c","\u003e", "\u0026", "\u2028", and "\u2029".
+// This replacement can be disabled when using an Encoder,
+// by calling SetEscapeHTML(false).
+//
+// Array and slice values encode as JSON arrays, except that
+// []byte encodes as a base64-encoded string, and a nil slice
+// encodes as the null JSON value.
+//
+// Struct values encode as JSON objects.
+// Each exported struct field becomes a member of the object, using the
+// field name as the object key, unless the field is omitted for one of the
+// reasons given below.
+//
+// The encoding of each struct field can be customized by the format string
+// stored under the "json" key in the struct field's tag.
+// The format string gives the name of the field, possibly followed by a
+// comma-separated list of options. The name may be empty in order to
+// specify options without overriding the default field name.
+//
+// The "omitempty" option specifies that the field should be omitted
+// from the encoding if the field has an empty value, defined as
+// false, 0, a nil pointer, a nil interface value, and any empty array,
+// slice, map, or string.
+//
+// As a special case, if the field tag is "-", the field is always omitted.
+// Note that a field with name "-" can still be generated using the tag "-,".
+//
+// Examples of struct field tags and their meanings:
+//
+// // Field appears in JSON as key "myName".
+// Field int `json:"myName"`
+//
+// // Field appears in JSON as key "myName" and
+// // the field is omitted from the object if its value is empty,
+// // as defined above.
+// Field int `json:"myName,omitempty"`
+//
+// // Field appears in JSON as key "Field" (the default), but
+// // the field is skipped if empty.
+// // Note the leading comma.
+// Field int `json:",omitempty"`
+//
+// // Field is ignored by this package.
+// Field int `json:"-"`
+//
+// // Field appears in JSON as key "-".
+// Field int `json:"-,"`
+//
+// The "string" option signals that a field is stored as JSON inside a
+// JSON-encoded string. It applies only to fields of string, floating point,
+// integer, or boolean types. This extra level of encoding is sometimes used
+// when communicating with JavaScript programs:
+//
+// Int64String int64 `json:",string"`
+//
+// The key name will be used if it's a non-empty string consisting of
+// only Unicode letters, digits, and ASCII punctuation except quotation
+// marks, backslash, and comma.
+//
+// Anonymous struct fields are usually marshaled as if their inner exported fields
+// were fields in the outer struct, subject to the usual Go visibility rules amended
+// as described in the next paragraph.
+// An anonymous struct field with a name given in its JSON tag is treated as
+// having that name, rather than being anonymous.
+// An anonymous struct field of interface type is treated the same as having
+// that type as its name, rather than being anonymous.
+//
+// The Go visibility rules for struct fields are amended for JSON when
+// deciding which field to marshal or unmarshal. If there are
+// multiple fields at the same level, and that level is the least
+// nested (and would therefore be the nesting level selected by the
+// usual Go rules), the following extra rules apply:
+//
+// 1) Of those fields, if any are JSON-tagged, only tagged fields are considered,
+// even if there are multiple untagged fields that would otherwise conflict.
+//
+// 2) If there is exactly one field (tagged or not according to the first rule), that is selected.
+//
+// 3) Otherwise there are multiple fields, and all are ignored; no error occurs.
+//
+// Handling of anonymous struct fields is new in Go 1.1.
+// Prior to Go 1.1, anonymous struct fields were ignored. To force ignoring of
+// an anonymous struct field in both current and earlier versions, give the field
+// a JSON tag of "-".
+//
+// Map values encode as JSON objects. The map's key type must either be a
+// string, an integer type, or implement encoding.TextMarshaler. The map keys
+// are sorted and used as JSON object keys by applying the following rules,
+// subject to the UTF-8 coercion described for string values above:
+// - keys of any string type are used directly
+// - encoding.TextMarshalers are marshaled
+// - integer keys are converted to strings
+//
+// Pointer values encode as the value pointed to.
+// A nil pointer encodes as the null JSON value.
+//
+// Interface values encode as the value contained in the interface.
+// A nil interface value encodes as the null JSON value.
+//
+// Channel, complex, and function values cannot be encoded in JSON.
+// Attempting to encode such a value causes Marshal to return
+// an UnsupportedTypeError.
+//
+// JSON cannot represent cyclic data structures and Marshal does not
+// handle them. Passing cyclic structures to Marshal will result in
+// an error.
+//
+func Marshal(v interface{}) ([]byte, error) {
+ e := newEncodeState()
+
+ err := e.marshal(v, encOpts{escapeHTML: true})
+ if err != nil {
+ return nil, err
+ }
+ buf := append([]byte(nil), e.Bytes()...)
+
+ encodeStatePool.Put(e)
+
+ return buf, nil
+}
+
+// MarshalIndent is like Marshal but applies Indent to format the output.
+// Each JSON element in the output will begin on a new line beginning with prefix
+// followed by one or more copies of indent according to the indentation nesting.
+func MarshalIndent(v interface{}, prefix, indent string) ([]byte, error) {
+ b, err := Marshal(v)
+ if err != nil {
+ return nil, err
+ }
+ var buf bytes.Buffer
+ err = Indent(&buf, b, prefix, indent)
+ if err != nil {
+ return nil, err
+ }
+ return buf.Bytes(), nil
+}
+
+// HTMLEscape appends to dst the JSON-encoded src with <, >, &, U+2028 and U+2029
+// characters inside string literals changed to \u003c, \u003e, \u0026, \u2028, \u2029
+// so that the JSON will be safe to embed inside HTML <script> tags.
+// For historical reasons, web browsers don't honor standard HTML
+// escaping within <script> tags, so an alternative JSON encoding must
+// be used.
+func HTMLEscape(dst *bytes.Buffer, src []byte) {
+ // The characters can only appear in string literals,
+ // so just scan the string one byte at a time.
+ start := 0
+ for i, c := range src {
+ if c == '<' || c == '>' || c == '&' {
+ if start < i {
+ dst.Write(src[start:i])
+ }
+ dst.WriteString(`\u00`)
+ dst.WriteByte(hex[c>>4])
+ dst.WriteByte(hex[c&0xF])
+ start = i + 1
+ }
+ // Convert U+2028 and U+2029 (E2 80 A8 and E2 80 A9).
+ if c == 0xE2 && i+2 < len(src) && src[i+1] == 0x80 && src[i+2]&^1 == 0xA8 {
+ if start < i {
+ dst.Write(src[start:i])
+ }
+ dst.WriteString(`\u202`)
+ dst.WriteByte(hex[src[i+2]&0xF])
+ start = i + 3
+ }
+ }
+ if start < len(src) {
+ dst.Write(src[start:])
+ }
+}
+
+// Marshaler is the interface implemented by types that
+// can marshal themselves into valid JSON.
+type Marshaler interface {
+ MarshalJSON() ([]byte, error)
+}
+
+// An UnsupportedTypeError is returned by Marshal when attempting
+// to encode an unsupported value type.
+type UnsupportedTypeError struct {
+ Type reflect.Type
+}
+
+func (e *UnsupportedTypeError) Error() string {
+ return "json: unsupported type: " + e.Type.String()
+}
+
+// An UnsupportedValueError is returned by Marshal when attempting
+// to encode an unsupported value.
+type UnsupportedValueError struct {
+ Value reflect.Value
+ Str string
+}
+
+func (e *UnsupportedValueError) Error() string {
+ return "json: unsupported value: " + e.Str
+}
+
+// Before Go 1.2, an InvalidUTF8Error was returned by Marshal when
+// attempting to encode a string value with invalid UTF-8 sequences.
+// As of Go 1.2, Marshal instead coerces the string to valid UTF-8 by
+// replacing invalid bytes with the Unicode replacement rune U+FFFD.
+//
+// Deprecated: No longer used; kept for compatibility.
+type InvalidUTF8Error struct {
+ S string // the whole string value that caused the error
+}
+
+func (e *InvalidUTF8Error) Error() string {
+ return "json: invalid UTF-8 in string: " + strconv.Quote(e.S)
+}
+
+// A MarshalerError represents an error from calling a MarshalJSON or MarshalText method.
+type MarshalerError struct {
+ Type reflect.Type
+ Err error
+ sourceFunc string
+}
+
+func (e *MarshalerError) Error() string {
+ srcFunc := e.sourceFunc
+ if srcFunc == "" {
+ srcFunc = "MarshalJSON"
+ }
+ return "json: error calling " + srcFunc +
+ " for type " + e.Type.String() +
+ ": " + e.Err.Error()
+}
+
+// Unwrap returns the underlying error.
+func (e *MarshalerError) Unwrap() error { return e.Err }
+
+var hex = "0123456789abcdef"
+
+// An encodeState encodes JSON into a bytes.Buffer.
+type encodeState struct {
+ bytes.Buffer // accumulated output
+ scratch [64]byte
+
+ // Keep track of what pointers we've seen in the current recursive call
+ // path, to avoid cycles that could lead to a stack overflow. Only do
+ // the relatively expensive map operations if ptrLevel is larger than
+ // startDetectingCyclesAfter, so that we skip the work if we're within a
+ // reasonable amount of nested pointers deep.
+ ptrLevel uint
+ ptrSeen map[interface{}]struct{}
+}
+
+const startDetectingCyclesAfter = 1000
+
+var encodeStatePool sync.Pool
+
+func newEncodeState() *encodeState {
+ if v := encodeStatePool.Get(); v != nil {
+ e := v.(*encodeState)
+ e.Reset()
+ if len(e.ptrSeen) > 0 {
+ panic("ptrEncoder.encode should have emptied ptrSeen via defers")
+ }
+ e.ptrLevel = 0
+ return e
+ }
+ return &encodeState{ptrSeen: make(map[interface{}]struct{})}
+}
+
+// jsonError is an error wrapper type for internal use only.
+// Panics with errors are wrapped in jsonError so that the top-level recover
+// can distinguish intentional panics from this package.
+type jsonError struct{ error }
+
+func (e *encodeState) marshal(v interface{}, opts encOpts) (err error) {
+ defer func() {
+ if r := recover(); r != nil {
+ if je, ok := r.(jsonError); ok {
+ err = je.error
+ } else {
+ panic(r)
+ }
+ }
+ }()
+ e.reflectValue(reflect.ValueOf(v), opts)
+ return nil
+}
+
+// error aborts the encoding by panicking with err wrapped in jsonError.
+func (e *encodeState) error(err error) {
+ panic(jsonError{err})
+}
+
+func isEmptyValue(v reflect.Value) bool {
+ switch v.Kind() {
+ case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+ return v.Len() == 0
+ case reflect.Bool:
+ return !v.Bool()
+ case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+ return v.Int() == 0
+ case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+ return v.Uint() == 0
+ case reflect.Float32, reflect.Float64:
+ return v.Float() == 0
+ case reflect.Interface, reflect.Ptr:
+ return v.IsNil()
+ }
+ return false
+}
+
+func (e *encodeState) reflectValue(v reflect.Value, opts encOpts) {
+ valueEncoder(v)(e, v, opts)
+}
+
+type encOpts struct {
+ // quoted causes primitive fields to be encoded inside JSON strings.
+ quoted bool
+ // escapeHTML causes '<', '>', and '&' to be escaped in JSON strings.
+ escapeHTML bool
+}
+
+type encoderFunc func(e *encodeState, v reflect.Value, opts encOpts)
+
+var encoderCache sync.Map // map[reflect.Type]encoderFunc
+
+func valueEncoder(v reflect.Value) encoderFunc {
+ if !v.IsValid() {
+ return invalidValueEncoder
+ }
+ return typeEncoder(v.Type())
+}
+
+func typeEncoder(t reflect.Type) encoderFunc {
+ if fi, ok := encoderCache.Load(t); ok {
+ return fi.(encoderFunc)
+ }
+
+ // To deal with recursive types, populate the map with an
+ // indirect func before we build it. This type waits on the
+ // real func (f) to be ready and then calls it. This indirect
+ // func is only used for recursive types.
+ var (
+ wg sync.WaitGroup
+ f encoderFunc
+ )
+ wg.Add(1)
+ fi, loaded := encoderCache.LoadOrStore(t, encoderFunc(func(e *encodeState, v reflect.Value, opts encOpts) {
+ wg.Wait()
+ f(e, v, opts)
+ }))
+ if loaded {
+ return fi.(encoderFunc)
+ }
+
+ // Compute the real encoder and replace the indirect func with it.
+ f = newTypeEncoder(t, true)
+ wg.Done()
+ encoderCache.Store(t, f)
+ return f
+}
+
+var (
+ marshalerType = reflect.TypeOf((*Marshaler)(nil)).Elem()
+ textMarshalerType = reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()
+)
+
+// newTypeEncoder constructs an encoderFunc for a type.
+// The returned encoder only checks CanAddr when allowAddr is true.
+func newTypeEncoder(t reflect.Type, allowAddr bool) encoderFunc {
+ // If we have a non-pointer value whose type implements
+ // Marshaler with a value receiver, then we're better off taking
+ // the address of the value - otherwise we end up with an
+ // allocation as we cast the value to an interface.
+ if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(marshalerType) {
+ return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false))
+ }
+ if t.Implements(marshalerType) {
+ return marshalerEncoder
+ }
+ if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(textMarshalerType) {
+ return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false))
+ }
+ if t.Implements(textMarshalerType) {
+ return textMarshalerEncoder
+ }
+
+ switch t.Kind() {
+ case reflect.Bool:
+ return boolEncoder
+ case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+ return intEncoder
+ case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+ return uintEncoder
+ case reflect.Float32:
+ return float32Encoder
+ case reflect.Float64:
+ return float64Encoder
+ case reflect.String:
+ return stringEncoder
+ case reflect.Interface:
+ return interfaceEncoder
+ case reflect.Struct:
+ return newStructEncoder(t)
+ case reflect.Map:
+ return newMapEncoder(t)
+ case reflect.Slice:
+ return newSliceEncoder(t)
+ case reflect.Array:
+ return newArrayEncoder(t)
+ case reflect.Ptr:
+ return newPtrEncoder(t)
+ default:
+ return unsupportedTypeEncoder
+ }
+}
+
+func invalidValueEncoder(e *encodeState, v reflect.Value, _ encOpts) {
+ e.WriteString("null")
+}
+
+func marshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+ if v.Kind() == reflect.Ptr && v.IsNil() {
+ e.WriteString("null")
+ return
+ }
+ m, ok := v.Interface().(Marshaler)
+ if !ok {
+ e.WriteString("null")
+ return
+ }
+ b, err := m.MarshalJSON()
+ if err == nil {
+ // copy JSON into buffer, checking validity.
+ err = compact(&e.Buffer, b, opts.escapeHTML)
+ }
+ if err != nil {
+ e.error(&MarshalerError{v.Type(), err, "MarshalJSON"})
+ }
+}
+
+func addrMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+ va := v.Addr()
+ if va.IsNil() {
+ e.WriteString("null")
+ return
+ }
+ m := va.Interface().(Marshaler)
+ b, err := m.MarshalJSON()
+ if err == nil {
+ // copy JSON into buffer, checking validity.
+ err = compact(&e.Buffer, b, opts.escapeHTML)
+ }
+ if err != nil {
+ e.error(&MarshalerError{v.Type(), err, "MarshalJSON"})
+ }
+}
+
+func textMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+ if v.Kind() == reflect.Ptr && v.IsNil() {
+ e.WriteString("null")
+ return
+ }
+ m, ok := v.Interface().(encoding.TextMarshaler)
+ if !ok {
+ e.WriteString("null")
+ return
+ }
+ b, err := m.MarshalText()
+ if err != nil {
+ e.error(&MarshalerError{v.Type(), err, "MarshalText"})
+ }
+ e.stringBytes(b, opts.escapeHTML)
+}
+
+func addrTextMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+ va := v.Addr()
+ if va.IsNil() {
+ e.WriteString("null")
+ return
+ }
+ m := va.Interface().(encoding.TextMarshaler)
+ b, err := m.MarshalText()
+ if err != nil {
+ e.error(&MarshalerError{v.Type(), err, "MarshalText"})
+ }
+ e.stringBytes(b, opts.escapeHTML)
+}
+
+func boolEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+ if v.Bool() {
+ e.WriteString("true")
+ } else {
+ e.WriteString("false")
+ }
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+}
+
+func intEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+ b := strconv.AppendInt(e.scratch[:0], v.Int(), 10)
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+ e.Write(b)
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+}
+
+func uintEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+ b := strconv.AppendUint(e.scratch[:0], v.Uint(), 10)
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+ e.Write(b)
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+}
+
+type floatEncoder int // number of bits
+
+func (bits floatEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
+ f := v.Float()
+ if math.IsInf(f, 0) || math.IsNaN(f) {
+ e.error(&UnsupportedValueError{v, strconv.FormatFloat(f, 'g', -1, int(bits))})
+ }
+
+ // Convert as if by ES6 number to string conversion.
+ // This matches most other JSON generators.
+ // See golang.org/issue/6384 and golang.org/issue/14135.
+ // Like fmt %g, but the exponent cutoffs are different
+ // and exponents themselves are not padded to two digits.
+ b := e.scratch[:0]
+ abs := math.Abs(f)
+ fmt := byte('f')
+ // Note: Must use float32 comparisons for underlying float32 value to get precise cutoffs right.
+ if abs != 0 {
+ if bits == 64 && (abs < 1e-6 || abs >= 1e21) || bits == 32 && (float32(abs) < 1e-6 || float32(abs) >= 1e21) {
+ fmt = 'e'
+ }
+ }
+ b = strconv.AppendFloat(b, f, fmt, -1, int(bits))
+ if fmt == 'e' {
+ // clean up e-09 to e-9
+ n := len(b)
+ if n >= 4 && b[n-4] == 'e' && b[n-3] == '-' && b[n-2] == '0' {
+ b[n-2] = b[n-1]
+ b = b[:n-1]
+ }
+ }
+
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+ e.Write(b)
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+}
+
+var (
+ float32Encoder = (floatEncoder(32)).encode
+ float64Encoder = (floatEncoder(64)).encode
+)
+
+func stringEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+ if v.Type() == numberType {
+ numStr := v.String()
+ // In Go1.5 the empty string encodes to "0", while this is not a valid number literal
+ // we keep compatibility so check validity after this.
+ if numStr == "" {
+ numStr = "0" // Number's zero-val
+ }
+ if !isValidNumber(numStr) {
+ e.error(fmt.Errorf("json: invalid number literal %q", numStr))
+ }
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+ e.WriteString(numStr)
+ if opts.quoted {
+ e.WriteByte('"')
+ }
+ return
+ }
+ if opts.quoted {
+ e2 := newEncodeState()
+ // Since we encode the string twice, we only need to escape HTML
+ // the first time.
+ e2.string(v.String(), opts.escapeHTML)
+ e.stringBytes(e2.Bytes(), false)
+ encodeStatePool.Put(e2)
+ } else {
+ e.string(v.String(), opts.escapeHTML)
+ }
+}
+
+// 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://www.json.org/img/number.png
+
+ 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 == ""
+}
+
+func interfaceEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+ if v.IsNil() {
+ e.WriteString("null")
+ return
+ }
+ e.reflectValue(v.Elem(), opts)
+}
+
+func unsupportedTypeEncoder(e *encodeState, v reflect.Value, _ encOpts) {
+ e.error(&UnsupportedTypeError{v.Type()})
+}
+
+type structEncoder struct {
+ fields structFields
+}
+
+type structFields struct {
+ list []field
+ nameIndex map[string]int
+}
+
+func (se structEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
+ next := byte('{')
+FieldLoop:
+ for i := range se.fields.list {
+ f := &se.fields.list[i]
+
+ // Find the nested struct field by following f.index.
+ fv := v
+ for _, i := range f.index {
+ if fv.Kind() == reflect.Ptr {
+ if fv.IsNil() {
+ continue FieldLoop
+ }
+ fv = fv.Elem()
+ }
+ fv = fv.Field(i)
+ }
+
+ if f.omitEmpty && isEmptyValue(fv) {
+ continue
+ }
+ e.WriteByte(next)
+ next = ','
+ if opts.escapeHTML {
+ e.WriteString(f.nameEscHTML)
+ } else {
+ e.WriteString(f.nameNonEsc)
+ }
+ opts.quoted = f.quoted
+ f.encoder(e, fv, opts)
+ }
+ if next == '{' {
+ e.WriteString("{}")
+ } else {
+ e.WriteByte('}')
+ }
+}
+
+func newStructEncoder(t reflect.Type) encoderFunc {
+ se := structEncoder{fields: cachedTypeFields(t)}
+ return se.encode
+}
+
+type mapEncoder struct {
+ elemEnc encoderFunc
+}
+
+func (me mapEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
+ if v.IsNil() {
+ e.WriteString("null")
+ return
+ }
+ if e.ptrLevel++; e.ptrLevel > startDetectingCyclesAfter {
+ // We're a large number of nested ptrEncoder.encode calls deep;
+ // start checking if we've run into a pointer cycle.
+ ptr := v.Pointer()
+ if _, ok := e.ptrSeen[ptr]; ok {
+ e.error(&UnsupportedValueError{v, fmt.Sprintf("encountered a cycle via %s", v.Type())})
+ }
+ e.ptrSeen[ptr] = struct{}{}
+ defer delete(e.ptrSeen, ptr)
+ }
+ e.WriteByte('{')
+
+ // Extract and sort the keys.
+ keys := v.MapKeys()
+ sv := make([]reflectWithString, len(keys))
+ for i, v := range keys {
+ sv[i].v = v
+ if err := sv[i].resolve(); err != nil {
+ e.error(fmt.Errorf("json: encoding error for type %q: %q", v.Type().String(), err.Error()))
+ }
+ }
+ sort.Slice(sv, func(i, j int) bool { return sv[i].s < sv[j].s })
+
+ for i, kv := range sv {
+ if i > 0 {
+ e.WriteByte(',')
+ }
+ e.string(kv.s, opts.escapeHTML)
+ e.WriteByte(':')
+ me.elemEnc(e, v.MapIndex(kv.v), opts)
+ }
+ e.WriteByte('}')
+ e.ptrLevel--
+}
+
+func newMapEncoder(t reflect.Type) encoderFunc {
+ 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 !t.Key().Implements(textMarshalerType) {
+ return unsupportedTypeEncoder
+ }
+ }
+ me := mapEncoder{typeEncoder(t.Elem())}
+ return me.encode
+}
+
+func encodeByteSlice(e *encodeState, v reflect.Value, _ encOpts) {
+ if v.IsNil() {
+ e.WriteString("null")
+ return
+ }
+ s := v.Bytes()
+ e.WriteByte('"')
+ encodedLen := base64.StdEncoding.EncodedLen(len(s))
+ if encodedLen <= len(e.scratch) {
+ // If the encoded bytes fit in e.scratch, avoid an extra
+ // allocation and use the cheaper Encoding.Encode.
+ dst := e.scratch[:encodedLen]
+ base64.StdEncoding.Encode(dst, s)
+ e.Write(dst)
+ } else if encodedLen <= 1024 {
+ // The encoded bytes are short enough to allocate for, and
+ // Encoding.Encode is still cheaper.
+ dst := make([]byte, encodedLen)
+ base64.StdEncoding.Encode(dst, s)
+ e.Write(dst)
+ } else {
+ // The encoded bytes are too long to cheaply allocate, and
+ // Encoding.Encode is no longer noticeably cheaper.
+ enc := base64.NewEncoder(base64.StdEncoding, e)
+ enc.Write(s)
+ enc.Close()
+ }
+ e.WriteByte('"')
+}
+
+// sliceEncoder just wraps an arrayEncoder, checking to make sure the value isn't nil.
+type sliceEncoder struct {
+ arrayEnc encoderFunc
+}
+
+func (se sliceEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
+ if v.IsNil() {
+ e.WriteString("null")
+ return
+ }
+ if e.ptrLevel++; e.ptrLevel > startDetectingCyclesAfter {
+ // We're a large number of nested ptrEncoder.encode calls deep;
+ // start checking if we've run into a pointer cycle.
+ // Here we use a struct to memorize the pointer to the first element of the slice
+ // and its length.
+ ptr := struct {
+ ptr uintptr
+ len int
+ }{v.Pointer(), v.Len()}
+ if _, ok := e.ptrSeen[ptr]; ok {
+ e.error(&UnsupportedValueError{v, fmt.Sprintf("encountered a cycle via %s", v.Type())})
+ }
+ e.ptrSeen[ptr] = struct{}{}
+ defer delete(e.ptrSeen, ptr)
+ }
+ se.arrayEnc(e, v, opts)
+ e.ptrLevel--
+}
+
+func newSliceEncoder(t reflect.Type) encoderFunc {
+ // Byte slices get special treatment; arrays don't.
+ if t.Elem().Kind() == reflect.Uint8 {
+ p := reflect.PtrTo(t.Elem())
+ if !p.Implements(marshalerType) && !p.Implements(textMarshalerType) {
+ return encodeByteSlice
+ }
+ }
+ enc := sliceEncoder{newArrayEncoder(t)}
+ return enc.encode
+}
+
+type arrayEncoder struct {
+ elemEnc encoderFunc
+}
+
+func (ae arrayEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
+ e.WriteByte('[')
+ n := v.Len()
+ for i := 0; i < n; i++ {
+ if i > 0 {
+ e.WriteByte(',')
+ }
+ ae.elemEnc(e, v.Index(i), opts)
+ }
+ e.WriteByte(']')
+}
+
+func newArrayEncoder(t reflect.Type) encoderFunc {
+ enc := arrayEncoder{typeEncoder(t.Elem())}
+ return enc.encode
+}
+
+type ptrEncoder struct {
+ elemEnc encoderFunc
+}
+
+func (pe ptrEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
+ if v.IsNil() {
+ e.WriteString("null")
+ return
+ }
+ if e.ptrLevel++; e.ptrLevel > startDetectingCyclesAfter {
+ // We're a large number of nested ptrEncoder.encode calls deep;
+ // start checking if we've run into a pointer cycle.
+ ptr := v.Interface()
+ if _, ok := e.ptrSeen[ptr]; ok {
+ e.error(&UnsupportedValueError{v, fmt.Sprintf("encountered a cycle via %s", v.Type())})
+ }
+ e.ptrSeen[ptr] = struct{}{}
+ defer delete(e.ptrSeen, ptr)
+ }
+ pe.elemEnc(e, v.Elem(), opts)
+ e.ptrLevel--
+}
+
+func newPtrEncoder(t reflect.Type) encoderFunc {
+ enc := ptrEncoder{typeEncoder(t.Elem())}
+ return enc.encode
+}
+
+type condAddrEncoder struct {
+ canAddrEnc, elseEnc encoderFunc
+}
+
+func (ce condAddrEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
+ if v.CanAddr() {
+ ce.canAddrEnc(e, v, opts)
+ } else {
+ ce.elseEnc(e, v, opts)
+ }
+}
+
+// newCondAddrEncoder returns an encoder that checks whether its value
+// CanAddr and delegates to canAddrEnc if so, else to elseEnc.
+func newCondAddrEncoder(canAddrEnc, elseEnc encoderFunc) encoderFunc {
+ enc := condAddrEncoder{canAddrEnc: canAddrEnc, elseEnc: elseEnc}
+ return enc.encode
+}
+
+func isValidTag(s string) bool {
+ if s == "" {
+ return false
+ }
+ for _, c := range s {
+ switch {
+ case strings.ContainsRune("!#$%&()*+-./:;<=>?@[]^_{|}~ ", c):
+ // Backslash and quote chars are reserved, but
+ // otherwise any punctuation chars are allowed
+ // in a tag name.
+ case !unicode.IsLetter(c) && !unicode.IsDigit(c):
+ return false
+ }
+ }
+ return true
+}
+
+func typeByIndex(t reflect.Type, index []int) reflect.Type {
+ for _, i := range index {
+ if t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ t = t.Field(i).Type
+ }
+ return t
+}
+
+type reflectWithString struct {
+ v reflect.Value
+ s string
+}
+
+func (w *reflectWithString) resolve() error {
+ if w.v.Kind() == reflect.String {
+ w.s = w.v.String()
+ return nil
+ }
+ if tm, ok := w.v.Interface().(encoding.TextMarshaler); ok {
+ if w.v.Kind() == reflect.Ptr && w.v.IsNil() {
+ return nil
+ }
+ buf, err := tm.MarshalText()
+ w.s = string(buf)
+ return err
+ }
+ switch w.v.Kind() {
+ case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+ w.s = strconv.FormatInt(w.v.Int(), 10)
+ return nil
+ case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+ w.s = strconv.FormatUint(w.v.Uint(), 10)
+ return nil
+ }
+ panic("unexpected map key type")
+}
+
+// NOTE: keep in sync with stringBytes below.
+func (e *encodeState) string(s string, escapeHTML bool) {
+ e.WriteByte('"')
+ start := 0
+ for i := 0; i < len(s); {
+ if b := s[i]; b < utf8.RuneSelf {
+ if htmlSafeSet[b] || (!escapeHTML && safeSet[b]) {
+ i++
+ continue
+ }
+ if start < i {
+ e.WriteString(s[start:i])
+ }
+ e.WriteByte('\\')
+ switch b {
+ case '\\', '"':
+ e.WriteByte(b)
+ case '\n':
+ e.WriteByte('n')
+ case '\r':
+ e.WriteByte('r')
+ case '\t':
+ e.WriteByte('t')
+ default:
+ // This encodes bytes < 0x20 except for \t, \n and \r.
+ // If escapeHTML is set, it also escapes <, >, and &
+ // because they can lead to security holes when
+ // user-controlled strings are rendered into JSON
+ // and served to some browsers.
+ e.WriteString(`u00`)
+ e.WriteByte(hex[b>>4])
+ e.WriteByte(hex[b&0xF])
+ }
+ i++
+ start = i
+ continue
+ }
+ c, size := utf8.DecodeRuneInString(s[i:])
+ if c == utf8.RuneError && size == 1 {
+ if start < i {
+ e.WriteString(s[start:i])
+ }
+ e.WriteString(`\ufffd`)
+ i += size
+ start = i
+ continue
+ }
+ // U+2028 is LINE SEPARATOR.
+ // U+2029 is PARAGRAPH SEPARATOR.
+ // They are both technically valid characters in JSON strings,
+ // but don't work in JSONP, which has to be evaluated as JavaScript,
+ // and can lead to security holes there. It is valid JSON to
+ // escape them, so we do so unconditionally.
+ // See http://timelessrepo.com/json-isnt-a-javascript-subset for discussion.
+ if c == '\u2028' || c == '\u2029' {
+ if start < i {
+ e.WriteString(s[start:i])
+ }
+ e.WriteString(`\u202`)
+ e.WriteByte(hex[c&0xF])
+ i += size
+ start = i
+ continue
+ }
+ i += size
+ }
+ if start < len(s) {
+ e.WriteString(s[start:])
+ }
+ e.WriteByte('"')
+}
+
+// NOTE: keep in sync with string above.
+func (e *encodeState) stringBytes(s []byte, escapeHTML bool) {
+ e.WriteByte('"')
+ start := 0
+ for i := 0; i < len(s); {
+ if b := s[i]; b < utf8.RuneSelf {
+ if htmlSafeSet[b] || (!escapeHTML && safeSet[b]) {
+ i++
+ continue
+ }
+ if start < i {
+ e.Write(s[start:i])
+ }
+ e.WriteByte('\\')
+ switch b {
+ case '\\', '"':
+ e.WriteByte(b)
+ case '\n':
+ e.WriteByte('n')
+ case '\r':
+ e.WriteByte('r')
+ case '\t':
+ e.WriteByte('t')
+ default:
+ // This encodes bytes < 0x20 except for \t, \n and \r.
+ // If escapeHTML is set, it also escapes <, >, and &
+ // because they can lead to security holes when
+ // user-controlled strings are rendered into JSON
+ // and served to some browsers.
+ e.WriteString(`u00`)
+ e.WriteByte(hex[b>>4])
+ e.WriteByte(hex[b&0xF])
+ }
+ i++
+ start = i
+ continue
+ }
+ c, size := utf8.DecodeRune(s[i:])
+ if c == utf8.RuneError && size == 1 {
+ if start < i {
+ e.Write(s[start:i])
+ }
+ e.WriteString(`\ufffd`)
+ i += size
+ start = i
+ continue
+ }
+ // U+2028 is LINE SEPARATOR.
+ // U+2029 is PARAGRAPH SEPARATOR.
+ // They are both technically valid characters in JSON strings,
+ // but don't work in JSONP, which has to be evaluated as JavaScript,
+ // and can lead to security holes there. It is valid JSON to
+ // escape them, so we do so unconditionally.
+ // See http://timelessrepo.com/json-isnt-a-javascript-subset for discussion.
+ if c == '\u2028' || c == '\u2029' {
+ if start < i {
+ e.Write(s[start:i])
+ }
+ e.WriteString(`\u202`)
+ e.WriteByte(hex[c&0xF])
+ i += size
+ start = i
+ continue
+ }
+ i += size
+ }
+ if start < len(s) {
+ e.Write(s[start:])
+ }
+ e.WriteByte('"')
+}
+
+// A field represents a single field found in a struct.
+type field struct {
+ name string
+ nameBytes []byte // []byte(name)
+ equalFold func(s, t []byte) bool // bytes.EqualFold or equivalent
+
+ nameNonEsc string // `"` + name + `":`
+ nameEscHTML string // `"` + HTMLEscape(name) + `":`
+
+ tag bool
+ index []int
+ typ reflect.Type
+ omitEmpty bool
+ quoted bool
+
+ encoder encoderFunc
+}
+
+// byIndex sorts field by index sequence.
+type byIndex []field
+
+func (x byIndex) Len() int { return len(x) }
+
+func (x byIndex) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+
+func (x byIndex) Less(i, j int) bool {
+ for k, xik := range x[i].index {
+ if k >= len(x[j].index) {
+ return false
+ }
+ if xik != x[j].index[k] {
+ return xik < x[j].index[k]
+ }
+ }
+ return len(x[i].index) < len(x[j].index)
+}
+
+// typeFields returns a list of fields that JSON should recognize for the given type.
+// The algorithm is breadth-first search over the set of structs to include - the top struct
+// and then any reachable anonymous structs.
+func typeFields(t reflect.Type) structFields {
+ // Anonymous fields to explore at the current level and the next.
+ current := []field{}
+ next := []field{{typ: t}}
+
+ // Count of queued names for current level and the next.
+ var count, nextCount map[reflect.Type]int
+
+ // Types already visited at an earlier level.
+ visited := map[reflect.Type]bool{}
+
+ // Fields found.
+ var fields []field
+
+ // Buffer to run HTMLEscape on field names.
+ var nameEscBuf bytes.Buffer
+
+ for len(next) > 0 {
+ current, next = next, current[:0]
+ count, nextCount = nextCount, map[reflect.Type]int{}
+
+ for _, f := range current {
+ if visited[f.typ] {
+ continue
+ }
+ visited[f.typ] = true
+
+ // Scan f.typ for fields to include.
+ for i := 0; i < f.typ.NumField(); i++ {
+ sf := f.typ.Field(i)
+ isUnexported := sf.PkgPath != ""
+ if sf.Anonymous {
+ t := sf.Type
+ if t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ if isUnexported && t.Kind() != reflect.Struct {
+ // Ignore embedded fields of unexported non-struct types.
+ continue
+ }
+ // Do not ignore embedded fields of unexported struct types
+ // since they may have exported fields.
+ } else if isUnexported {
+ // Ignore unexported non-embedded fields.
+ continue
+ }
+ tag := sf.Tag.Get("json")
+ if tag == "-" {
+ continue
+ }
+ name, opts := parseTag(tag)
+ if !isValidTag(name) {
+ name = ""
+ }
+ index := make([]int, len(f.index)+1)
+ copy(index, f.index)
+ index[len(f.index)] = i
+
+ ft := sf.Type
+ if ft.Name() == "" && ft.Kind() == reflect.Ptr {
+ // Follow pointer.
+ ft = ft.Elem()
+ }
+
+ // Only strings, floats, integers, and booleans can be quoted.
+ quoted := false
+ if opts.Contains("string") {
+ switch ft.Kind() {
+ case reflect.Bool,
+ reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+ reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr,
+ reflect.Float32, reflect.Float64,
+ reflect.String:
+ quoted = true
+ }
+ }
+
+ // Record found field and index sequence.
+ if name != "" || !sf.Anonymous || ft.Kind() != reflect.Struct {
+ tagged := name != ""
+ if name == "" {
+ name = sf.Name
+ }
+ field := field{
+ name: name,
+ tag: tagged,
+ index: index,
+ typ: ft,
+ omitEmpty: opts.Contains("omitempty"),
+ quoted: quoted,
+ }
+ field.nameBytes = []byte(field.name)
+ field.equalFold = foldFunc(field.nameBytes)
+
+ // Build nameEscHTML and nameNonEsc ahead of time.
+ nameEscBuf.Reset()
+ nameEscBuf.WriteString(`"`)
+ HTMLEscape(&nameEscBuf, field.nameBytes)
+ nameEscBuf.WriteString(`":`)
+ field.nameEscHTML = nameEscBuf.String()
+ field.nameNonEsc = `"` + field.name + `":`
+
+ fields = append(fields, field)
+ if count[f.typ] > 1 {
+ // If there were multiple instances, add a second,
+ // so that the annihilation code will see a duplicate.
+ // It only cares about the distinction between 1 or 2,
+ // so don't bother generating any more copies.
+ fields = append(fields, fields[len(fields)-1])
+ }
+ continue
+ }
+
+ // Record new anonymous struct to explore in next round.
+ nextCount[ft]++
+ if nextCount[ft] == 1 {
+ next = append(next, field{name: ft.Name(), index: index, typ: ft})
+ }
+ }
+ }
+ }
+
+ sort.Slice(fields, func(i, j int) bool {
+ x := fields
+ // sort field by name, breaking ties with depth, then
+ // breaking ties with "name came from json tag", then
+ // breaking ties with index sequence.
+ if x[i].name != x[j].name {
+ return x[i].name < x[j].name
+ }
+ if len(x[i].index) != len(x[j].index) {
+ return len(x[i].index) < len(x[j].index)
+ }
+ if x[i].tag != x[j].tag {
+ return x[i].tag
+ }
+ return byIndex(x).Less(i, j)
+ })
+
+ // Delete all fields that are hidden by the Go rules for embedded fields,
+ // except that fields with JSON tags are promoted.
+
+ // The fields are sorted in primary order of name, secondary order
+ // of field index length. Loop over names; for each name, delete
+ // hidden fields by choosing the one dominant field that survives.
+ out := fields[:0]
+ for advance, i := 0, 0; i < len(fields); i += advance {
+ // One iteration per name.
+ // Find the sequence of fields with the name of this first field.
+ fi := fields[i]
+ name := fi.name
+ for advance = 1; i+advance < len(fields); advance++ {
+ fj := fields[i+advance]
+ if fj.name != name {
+ break
+ }
+ }
+ if advance == 1 { // Only one field with this name
+ out = append(out, fi)
+ continue
+ }
+ dominant, ok := dominantField(fields[i : i+advance])
+ if ok {
+ out = append(out, dominant)
+ }
+ }
+
+ fields = out
+ sort.Sort(byIndex(fields))
+
+ for i := range fields {
+ f := &fields[i]
+ f.encoder = typeEncoder(typeByIndex(t, f.index))
+ }
+ nameIndex := make(map[string]int, len(fields))
+ for i, field := range fields {
+ nameIndex[field.name] = i
+ }
+ return structFields{fields, nameIndex}
+}
+
+// dominantField looks through the fields, all of which are known to
+// have the same name, to find the single field that dominates the
+// others using Go's embedding rules, modified by the presence of
+// JSON tags. If there are multiple top-level fields, the boolean
+// will be false: This condition is an error in Go and we skip all
+// the fields.
+func dominantField(fields []field) (field, bool) {
+ // The fields are sorted in increasing index-length order, then by presence of tag.
+ // That means that the first field is the dominant one. We need only check
+ // for error cases: two fields at top level, either both tagged or neither tagged.
+ if len(fields) > 1 && len(fields[0].index) == len(fields[1].index) && fields[0].tag == fields[1].tag {
+ return field{}, false
+ }
+ return fields[0], true
+}
+
+var fieldCache sync.Map // map[reflect.Type]structFields
+
+// cachedTypeFields is like typeFields but uses a cache to avoid repeated work.
+func cachedTypeFields(t reflect.Type) structFields {
+ if f, ok := fieldCache.Load(t); ok {
+ return f.(structFields)
+ }
+ f, _ := fieldCache.LoadOrStore(t, typeFields(t))
+ return f.(structFields)
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-22 20:09:13 +0000