diff options
Diffstat (limited to 'vendor/github.com/yaegashi/msgraph.go/jsonx/encode.go')
| -rw-r--r-- | vendor/github.com/yaegashi/msgraph.go/jsonx/encode.go | 1317 |
1 files changed, 1317 insertions, 0 deletions
diff --git a/vendor/github.com/yaegashi/msgraph.go/jsonx/encode.go b/vendor/github.com/yaegashi/msgraph.go/jsonx/encode.go new file mode 100644 index 00000000..7c155502 --- /dev/null +++ b/vendor/github.com/yaegashi/msgraph.go/jsonx/encode.go @@ -0,0 +1,1317 @@ +// 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 jsonx + +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 infinite recursion. +// +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()...) + + e.Reset() + 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() +} + +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 +} + +func (e *MarshalerError) Error() string { + return "json: error calling MarshalJSON for type " + e.Type.String() + ": " + e.Err.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 +} + +var encodeStatePool sync.Pool + +func newEncodeState() *encodeState { + if v := encodeStatePool.Get(); v != nil { + e := v.(*encodeState) + e.Reset() + return e + } + return new(encodeState) +} + +// 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 t.Implements(marshalerType) { + return marshalerEncoder + } + if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(marshalerType) { + return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false)) + } + + if t.Implements(textMarshalerType) { + return textMarshalerEncoder + } + if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(textMarshalerType) { + return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false)) + } + + 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}) + } +} + +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}) + } +} + +func textMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) { + if v.Kind() == reflect.Ptr && v.IsNil() { + e.WriteString("null") + return + } + m := v.Interface().(encoding.TextMarshaler) + b, err := m.MarshalText() + if err != nil { + e.error(&MarshalerError{v.Type(), err}) + } + 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}) + } + 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)) + } + e.WriteString(numStr) + return + } + if opts.quoted { + sb, err := Marshal(v.String()) + if err != nil { + e.error(err) + } + e.string(string(sb), opts.escapeHTML) + } else { + e.string(v.String(), opts.escapeHTML) + } +} + +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 + } + if f.extra { + keys := fv.MapKeys() + sv := make([]reflectWithString, len(keys)) + for i, v := range keys { + sv[i].v = v + if err := sv[i].resolve(); err != nil { + e.error(&MarshalerError{v.Type(), err}) + } + } + sort.Slice(sv, func(i, j int) bool { return sv[i].s < sv[j].s }) + elemEnc := typeEncoder(fv.Type().Elem()) + for _, kv := range sv { + e.WriteByte(next) + next = ',' + e.string(kv.s, opts.escapeHTML) + e.WriteByte(':') + elemEnc(e, fv.MapIndex(kv.v), opts) + } + 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 + } + 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(&MarshalerError{v.Type(), err}) + } + } + 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('}') +} + +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 + } + se.arrayEnc(e, v, opts) +} + +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 + } + pe.elemEnc(e, v.Elem(), opts) +} + +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 { + 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 + extra 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") + tagx := sf.Tag.Get("jsonx") + if tag == "-" && tagx == "" { + continue + } + if tagx != "" { + tag = "" + } + 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 maps can be extra. + extra := false + if tagx != "" { + switch ft.Kind() { + case reflect.Map: + extra = true + default: + continue + } + } + + // 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"), + extra: extra, + 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) +} |