encode.go raw
1 package yaml
2
3 import (
4 "encoding"
5 "fmt"
6 "io"
7 "reflect"
8 "regexp"
9 "sort"
10 "strconv"
11 "strings"
12 "time"
13 "unicode/utf8"
14 )
15
16 // jsonNumber is the interface of the encoding/json.Number datatype.
17 // Repeating the interface here avoids a dependency on encoding/json, and also
18 // supports other libraries like jsoniter, which use a similar datatype with
19 // the same interface. Detecting this interface is useful when dealing with
20 // structures containing json.Number, which is a string under the hood. The
21 // encoder should prefer the use of Int64(), Float64() and string(), in that
22 // order, when encoding this type.
23 type jsonNumber interface {
24 Float64() (float64, error)
25 Int64() (int64, error)
26 String() string
27 }
28
29 type encoder struct {
30 emitter yaml_emitter_t
31 event yaml_event_t
32 out []byte
33 flow bool
34 // doneInit holds whether the initial stream_start_event has been
35 // emitted.
36 doneInit bool
37 }
38
39 func newEncoder() *encoder {
40 e := &encoder{}
41 yaml_emitter_initialize(&e.emitter)
42 yaml_emitter_set_output_string(&e.emitter, &e.out)
43 yaml_emitter_set_unicode(&e.emitter, true)
44 return e
45 }
46
47 func newEncoderWithWriter(w io.Writer) *encoder {
48 e := &encoder{}
49 yaml_emitter_initialize(&e.emitter)
50 yaml_emitter_set_output_writer(&e.emitter, w)
51 yaml_emitter_set_unicode(&e.emitter, true)
52 return e
53 }
54
55 func (e *encoder) init() {
56 if e.doneInit {
57 return
58 }
59 yaml_stream_start_event_initialize(&e.event, yaml_UTF8_ENCODING)
60 e.emit()
61 e.doneInit = true
62 }
63
64 func (e *encoder) finish() {
65 e.emitter.open_ended = false
66 yaml_stream_end_event_initialize(&e.event)
67 e.emit()
68 }
69
70 func (e *encoder) destroy() {
71 yaml_emitter_delete(&e.emitter)
72 }
73
74 func (e *encoder) emit() {
75 // This will internally delete the e.event value.
76 e.must(yaml_emitter_emit(&e.emitter, &e.event))
77 }
78
79 func (e *encoder) must(ok bool) {
80 if !ok {
81 msg := e.emitter.problem
82 if msg == "" {
83 msg = "unknown problem generating YAML content"
84 }
85 failf("%s", msg)
86 }
87 }
88
89 func (e *encoder) marshalDoc(tag string, in reflect.Value) {
90 e.init()
91 yaml_document_start_event_initialize(&e.event, nil, nil, true)
92 e.emit()
93 e.marshal(tag, in)
94 yaml_document_end_event_initialize(&e.event, true)
95 e.emit()
96 }
97
98 func (e *encoder) marshal(tag string, in reflect.Value) {
99 if !in.IsValid() || in.Kind() == reflect.Ptr && in.IsNil() {
100 e.nilv()
101 return
102 }
103 iface := in.Interface()
104 switch m := iface.(type) {
105 case jsonNumber:
106 integer, err := m.Int64()
107 if err == nil {
108 // In this case the json.Number is a valid int64
109 in = reflect.ValueOf(integer)
110 break
111 }
112 float, err := m.Float64()
113 if err == nil {
114 // In this case the json.Number is a valid float64
115 in = reflect.ValueOf(float)
116 break
117 }
118 // fallback case - no number could be obtained
119 in = reflect.ValueOf(m.String())
120 case time.Time, *time.Time:
121 // Although time.Time implements TextMarshaler,
122 // we don't want to treat it as a string for YAML
123 // purposes because YAML has special support for
124 // timestamps.
125 case Marshaler:
126 v, err := m.MarshalYAML()
127 if err != nil {
128 fail(err)
129 }
130 if v == nil {
131 e.nilv()
132 return
133 }
134 in = reflect.ValueOf(v)
135 case encoding.TextMarshaler:
136 text, err := m.MarshalText()
137 if err != nil {
138 fail(err)
139 }
140 in = reflect.ValueOf(string(text))
141 case nil:
142 e.nilv()
143 return
144 }
145 switch in.Kind() {
146 case reflect.Interface:
147 e.marshal(tag, in.Elem())
148 case reflect.Map:
149 e.mapv(tag, in)
150 case reflect.Ptr:
151 if in.Type() == ptrTimeType {
152 e.timev(tag, in.Elem())
153 } else {
154 e.marshal(tag, in.Elem())
155 }
156 case reflect.Struct:
157 if in.Type() == timeType {
158 e.timev(tag, in)
159 } else {
160 e.structv(tag, in)
161 }
162 case reflect.Slice, reflect.Array:
163 if in.Type().Elem() == mapItemType {
164 e.itemsv(tag, in)
165 } else {
166 e.slicev(tag, in)
167 }
168 case reflect.String:
169 e.stringv(tag, in)
170 case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
171 if in.Type() == durationType {
172 e.stringv(tag, reflect.ValueOf(iface.(time.Duration).String()))
173 } else {
174 e.intv(tag, in)
175 }
176 case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
177 e.uintv(tag, in)
178 case reflect.Float32, reflect.Float64:
179 e.floatv(tag, in)
180 case reflect.Bool:
181 e.boolv(tag, in)
182 default:
183 panic("cannot marshal type: " + in.Type().String())
184 }
185 }
186
187 func (e *encoder) mapv(tag string, in reflect.Value) {
188 e.mappingv(tag, func() {
189 keys := keyList(in.MapKeys())
190 sort.Sort(keys)
191 for _, k := range keys {
192 e.marshal("", k)
193 e.marshal("", in.MapIndex(k))
194 }
195 })
196 }
197
198 func (e *encoder) itemsv(tag string, in reflect.Value) {
199 e.mappingv(tag, func() {
200 slice := in.Convert(reflect.TypeOf([]MapItem{})).Interface().([]MapItem)
201 for _, item := range slice {
202 e.marshal("", reflect.ValueOf(item.Key))
203 e.marshal("", reflect.ValueOf(item.Value))
204 }
205 })
206 }
207
208 func (e *encoder) structv(tag string, in reflect.Value) {
209 sinfo, err := getStructInfo(in.Type())
210 if err != nil {
211 panic(err)
212 }
213 e.mappingv(tag, func() {
214 for _, info := range sinfo.FieldsList {
215 var value reflect.Value
216 if info.Inline == nil {
217 value = in.Field(info.Num)
218 } else {
219 value = in.FieldByIndex(info.Inline)
220 }
221 if info.OmitEmpty && isZero(value) {
222 continue
223 }
224 e.marshal("", reflect.ValueOf(info.Key))
225 e.flow = info.Flow
226 e.marshal("", value)
227 }
228 if sinfo.InlineMap >= 0 {
229 m := in.Field(sinfo.InlineMap)
230 if m.Len() > 0 {
231 e.flow = false
232 keys := keyList(m.MapKeys())
233 sort.Sort(keys)
234 for _, k := range keys {
235 if _, found := sinfo.FieldsMap[k.String()]; found {
236 panic(fmt.Sprintf("Can't have key %q in inlined map; conflicts with struct field", k.String()))
237 }
238 e.marshal("", k)
239 e.flow = false
240 e.marshal("", m.MapIndex(k))
241 }
242 }
243 }
244 })
245 }
246
247 func (e *encoder) mappingv(tag string, f func()) {
248 implicit := tag == ""
249 style := yaml_BLOCK_MAPPING_STYLE
250 if e.flow {
251 e.flow = false
252 style = yaml_FLOW_MAPPING_STYLE
253 }
254 yaml_mapping_start_event_initialize(&e.event, nil, []byte(tag), implicit, style)
255 e.emit()
256 f()
257 yaml_mapping_end_event_initialize(&e.event)
258 e.emit()
259 }
260
261 func (e *encoder) slicev(tag string, in reflect.Value) {
262 implicit := tag == ""
263 style := yaml_BLOCK_SEQUENCE_STYLE
264 if e.flow {
265 e.flow = false
266 style = yaml_FLOW_SEQUENCE_STYLE
267 }
268 e.must(yaml_sequence_start_event_initialize(&e.event, nil, []byte(tag), implicit, style))
269 e.emit()
270 n := in.Len()
271 for i := 0; i < n; i++ {
272 e.marshal("", in.Index(i))
273 }
274 e.must(yaml_sequence_end_event_initialize(&e.event))
275 e.emit()
276 }
277
278 // isBase60 returns whether s is in base 60 notation as defined in YAML 1.1.
279 //
280 // The base 60 float notation in YAML 1.1 is a terrible idea and is unsupported
281 // in YAML 1.2 and by this package, but these should be marshalled quoted for
282 // the time being for compatibility with other parsers.
283 func isBase60Float(s string) (result bool) {
284 // Fast path.
285 if s == "" {
286 return false
287 }
288 c := s[0]
289 if !(c == '+' || c == '-' || c >= '0' && c <= '9') || strings.IndexByte(s, ':') < 0 {
290 return false
291 }
292 // Do the full match.
293 return base60float.MatchString(s)
294 }
295
296 // From http://yaml.org/type/float.html, except the regular expression there
297 // is bogus. In practice parsers do not enforce the "\.[0-9_]*" suffix.
298 var base60float = regexp.MustCompile(`^[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+(?:\.[0-9_]*)?$`)
299
300 func (e *encoder) stringv(tag string, in reflect.Value) {
301 var style yaml_scalar_style_t
302 s := in.String()
303 canUsePlain := true
304 switch {
305 case !utf8.ValidString(s):
306 if tag == yaml_BINARY_TAG {
307 failf("explicitly tagged !!binary data must be base64-encoded")
308 }
309 if tag != "" {
310 failf("cannot marshal invalid UTF-8 data as %s", shortTag(tag))
311 }
312 // It can't be encoded directly as YAML so use a binary tag
313 // and encode it as base64.
314 tag = yaml_BINARY_TAG
315 s = encodeBase64(s)
316 case tag == "":
317 // Check to see if it would resolve to a specific
318 // tag when encoded unquoted. If it doesn't,
319 // there's no need to quote it.
320 rtag, _ := resolve("", s)
321 canUsePlain = rtag == yaml_STR_TAG && !isBase60Float(s)
322 }
323 // Note: it's possible for user code to emit invalid YAML
324 // if they explicitly specify a tag and a string containing
325 // text that's incompatible with that tag.
326 switch {
327 case strings.Contains(s, "\n"):
328 style = yaml_LITERAL_SCALAR_STYLE
329 case canUsePlain:
330 style = yaml_PLAIN_SCALAR_STYLE
331 default:
332 style = yaml_DOUBLE_QUOTED_SCALAR_STYLE
333 }
334 e.emitScalar(s, "", tag, style)
335 }
336
337 func (e *encoder) boolv(tag string, in reflect.Value) {
338 var s string
339 if in.Bool() {
340 s = "true"
341 } else {
342 s = "false"
343 }
344 e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE)
345 }
346
347 func (e *encoder) intv(tag string, in reflect.Value) {
348 s := strconv.FormatInt(in.Int(), 10)
349 e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE)
350 }
351
352 func (e *encoder) uintv(tag string, in reflect.Value) {
353 s := strconv.FormatUint(in.Uint(), 10)
354 e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE)
355 }
356
357 func (e *encoder) timev(tag string, in reflect.Value) {
358 t := in.Interface().(time.Time)
359 s := t.Format(time.RFC3339Nano)
360 e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE)
361 }
362
363 func (e *encoder) floatv(tag string, in reflect.Value) {
364 // Issue #352: When formatting, use the precision of the underlying value
365 precision := 64
366 if in.Kind() == reflect.Float32 {
367 precision = 32
368 }
369
370 s := strconv.FormatFloat(in.Float(), 'g', -1, precision)
371 switch s {
372 case "+Inf":
373 s = ".inf"
374 case "-Inf":
375 s = "-.inf"
376 case "NaN":
377 s = ".nan"
378 }
379 e.emitScalar(s, "", tag, yaml_PLAIN_SCALAR_STYLE)
380 }
381
382 func (e *encoder) nilv() {
383 e.emitScalar("null", "", "", yaml_PLAIN_SCALAR_STYLE)
384 }
385
386 func (e *encoder) emitScalar(value, anchor, tag string, style yaml_scalar_style_t) {
387 implicit := tag == ""
388 e.must(yaml_scalar_event_initialize(&e.event, []byte(anchor), []byte(tag), []byte(value), implicit, implicit, style))
389 e.emit()
390 }
391