summaryrefslogblamecommitdiffstats
path: root/vendor/github.com/BurntSushi/toml/decode.go
blob: b0fd51d5b6ea51ef895ce862bacf566e577111ce (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509



























































































































































































































































































































































































































































































































                                                                                            
package toml

import (
	"fmt"
	"io"
	"io/ioutil"
	"math"
	"reflect"
	"strings"
	"time"
)

func e(format string, args ...interface{}) error {
	return fmt.Errorf("toml: "+format, args...)
}

// Unmarshaler is the interface implemented by objects that can unmarshal a
// TOML description of themselves.
type Unmarshaler interface {
	UnmarshalTOML(interface{}) error
}

// Unmarshal decodes the contents of `p` in TOML format into a pointer `v`.
func Unmarshal(p []byte, v interface{}) error {
	_, err := Decode(string(p), v)
	return err
}

// Primitive is a TOML value that hasn't been decoded into a Go value.
// When using the various `Decode*` functions, the type `Primitive` may
// be given to any value, and its decoding will be delayed.
//
// A `Primitive` value can be decoded using the `PrimitiveDecode` function.
//
// The underlying representation of a `Primitive` value is subject to change.
// Do not rely on it.
//
// N.B. Primitive values are still parsed, so using them will only avoid
// the overhead of reflection. They can be useful when you don't know the
// exact type of TOML data until run time.
type Primitive struct {
	undecoded interface{}
	context   Key
}

// DEPRECATED!
//
// Use MetaData.PrimitiveDecode instead.
func PrimitiveDecode(primValue Primitive, v interface{}) error {
	md := MetaData{decoded: make(map[string]bool)}
	return md.unify(primValue.undecoded, rvalue(v))
}

// PrimitiveDecode is just like the other `Decode*` functions, except it
// decodes a TOML value that has already been parsed. Valid primitive values
// can *only* be obtained from values filled by the decoder functions,
// including this method. (i.e., `v` may contain more `Primitive`
// values.)
//
// Meta data for primitive values is included in the meta data returned by
// the `Decode*` functions with one exception: keys returned by the Undecoded
// method will only reflect keys that were decoded. Namely, any keys hidden
// behind a Primitive will be considered undecoded. Executing this method will
// update the undecoded keys in the meta data. (See the example.)
func (md *MetaData) PrimitiveDecode(primValue Primitive, v interface{}) error {
	md.context = primValue.context
	defer func() { md.context = nil }()
	return md.unify(primValue.undecoded, rvalue(v))
}

// Decode will decode the contents of `data` in TOML format into a pointer
// `v`.
//
// TOML hashes correspond to Go structs or maps. (Dealer's choice. They can be
// used interchangeably.)
//
// TOML arrays of tables correspond to either a slice of structs or a slice
// of maps.
//
// TOML datetimes correspond to Go `time.Time` values.
//
// All other TOML types (float, string, int, bool and array) correspond
// to the obvious Go types.
//
// An exception to the above rules is if a type implements the
// encoding.TextUnmarshaler interface. In this case, any primitive TOML value
// (floats, strings, integers, booleans and datetimes) will be converted to
// a byte string and given to the value's UnmarshalText method. See the
// Unmarshaler example for a demonstration with time duration strings.
//
// Key mapping
//
// TOML keys can map to either keys in a Go map or field names in a Go
// struct. The special `toml` struct tag may be used to map TOML keys to
// struct fields that don't match the key name exactly. (See the example.)
// A case insensitive match to struct names will be tried if an exact match
// can't be found.
//
// The mapping between TOML values and Go values is loose. That is, there
// may exist TOML values that cannot be placed into your representation, and
// there may be parts of your representation that do not correspond to
// TOML values. This loose mapping can be made stricter by using the IsDefined
// and/or Undecoded methods on the MetaData returned.
//
// This decoder will not handle cyclic types. If a cyclic type is passed,
// `Decode` will not terminate.
func Decode(data string, v interface{}) (MetaData, error) {
	rv := reflect.ValueOf(v)
	if rv.Kind() != reflect.Ptr {
		return MetaData{}, e("Decode of non-pointer %s", reflect.TypeOf(v))
	}
	if rv.IsNil() {
		return MetaData{}, e("Decode of nil %s", reflect.TypeOf(v))
	}
	p, err := parse(data)
	if err != nil {
		return MetaData{}, err
	}
	md := MetaData{
		p.mapping, p.types, p.ordered,
		make(map[string]bool, len(p.ordered)), nil,
	}
	return md, md.unify(p.mapping, indirect(rv))
}

// DecodeFile is just like Decode, except it will automatically read the
// contents of the file at `fpath` and decode it for you.
func DecodeFile(fpath string, v interface{}) (MetaData, error) {
	bs, err := ioutil.ReadFile(fpath)
	if err != nil {
		return MetaData{}, err
	}
	return Decode(string(bs), v)
}

// DecodeReader is just like Decode, except it will consume all bytes
// from the reader and decode it for you.
func DecodeReader(r io.Reader, v interface{}) (MetaData, error) {
	bs, err := ioutil.ReadAll(r)
	if err != nil {
		return MetaData{}, err
	}
	return Decode(string(bs), v)
}

// unify performs a sort of type unification based on the structure of `rv`,
// which is the client representation.
//
// Any type mismatch produces an error. Finding a type that we don't know
// how to handle produces an unsupported type error.
func (md *MetaData) unify(data interface{}, rv reflect.Value) error {

	// Special case. Look for a `Primitive` value.
	if rv.Type() == reflect.TypeOf((*Primitive)(nil)).Elem() {
		// Save the undecoded data and the key context into the primitive
		// value.
		context := make(Key, len(md.context))
		copy(context, md.context)
		rv.Set(reflect.ValueOf(Primitive{
			undecoded: data,
			context:   context,
		}))
		return nil
	}

	// Special case. Unmarshaler Interface support.
	if rv.CanAddr() {
		if v, ok := rv.Addr().Interface().(Unmarshaler); ok {
			return v.UnmarshalTOML(data)
		}
	}

	// Special case. Handle time.Time values specifically.
	// TODO: Remove this code when we decide to drop support for Go 1.1.
	// This isn't necessary in Go 1.2 because time.Time satisfies the encoding
	// interfaces.
	if rv.Type().AssignableTo(rvalue(time.Time{}).Type()) {
		return md.unifyDatetime(data, rv)
	}

	// Special case. Look for a value satisfying the TextUnmarshaler interface.
	if v, ok := rv.Interface().(TextUnmarshaler); ok {
		return md.unifyText(data, v)
	}
	// BUG(burntsushi)
	// The behavior here is incorrect whenever a Go type satisfies the
	// encoding.TextUnmarshaler interface but also corresponds to a TOML
	// hash or array. In particular, the unmarshaler should only be applied
	// to primitive TOML values. But at this point, it will be applied to
	// all kinds of values and produce an incorrect error whenever those values
	// are hashes or arrays (including arrays of tables).

	k := rv.Kind()

	// laziness
	if k >= reflect.Int && k <= reflect.Uint64 {
		return md.unifyInt(data, rv)
	}
	switch k {
	case reflect.Ptr:
		elem := reflect.New(rv.Type().Elem())
		err := md.unify(data, reflect.Indirect(elem))
		if err != nil {
			return err
		}
		rv.Set(elem)
		return nil
	case reflect.Struct:
		return md.unifyStruct(data, rv)
	case reflect.Map:
		return md.unifyMap(data, rv)
	case reflect.Array:
		return md.unifyArray(data, rv)
	case reflect.Slice:
		return md.unifySlice(data, rv)
	case reflect.String:
		return md.unifyString(data, rv)
	case reflect.Bool:
		return md.unifyBool(data, rv)
	case reflect.Interface:
		// we only support empty interfaces.
		if rv.NumMethod() > 0 {
			return e("unsupported type %s", rv.Type())
		}
		return md.unifyAnything(data, rv)
	case reflect.Float32:
		fallthrough
	case reflect.Float64:
		return md.unifyFloat64(data, rv)
	}
	return e("unsupported type %s", rv.Kind())
}

func (md *MetaData) unifyStruct(mapping interface{}, rv reflect.Value) error {
	tmap, ok := mapping.(map[string]interface{})
	if !ok {
		if mapping == nil {
			return nil
		}
		return e("type mismatch for %s: expected table but found %T",
			rv.Type().String(), mapping)
	}

	for key, datum := range tmap {
		var f *field
		fields := cachedTypeFields(rv.Type())
		for i := range fields {
			ff := &fields[i]
			if ff.name == key {
				f = ff
				break
			}
			if f == nil && strings.EqualFold(ff.name, key) {
				f = ff
			}
		}
		if f != nil {
			subv := rv
			for _, i := range f.index {
				subv = indirect(subv.Field(i))
			}
			if isUnifiable(subv) {
				md.decoded[md.context.add(key).String()] = true
				md.context = append(md.context, key)
				if err := md.unify(datum, subv); err != nil {
					return err
				}
				md.context = md.context[0 : len(md.context)-1]
			} else if f.name != "" {
				// Bad user! No soup for you!
				return e("cannot write unexported field %s.%s",
					rv.Type().String(), f.name)
			}
		}
	}
	return nil
}

func (md *MetaData) unifyMap(mapping interface{}, rv reflect.Value) error {
	tmap, ok := mapping.(map[string]interface{})
	if !ok {
		if tmap == nil {
			return nil
		}
		return badtype("map", mapping)
	}
	if rv.IsNil() {
		rv.Set(reflect.MakeMap(rv.Type()))
	}
	for k, v := range tmap {
		md.decoded[md.context.add(k).String()] = true
		md.context = append(md.context, k)

		rvkey := indirect(reflect.New(rv.Type().Key()))
		rvval := reflect.Indirect(reflect.New(rv.Type().Elem()))
		if err := md.unify(v, rvval); err != nil {
			return err
		}
		md.context = md.context[0 : len(md.context)-1]

		rvkey.SetString(k)
		rv.SetMapIndex(rvkey, rvval)
	}
	return nil
}

func (md *MetaData) unifyArray(data interface{}, rv reflect.Value) error {
	datav := reflect.ValueOf(data)
	if datav.Kind() != reflect.Slice {
		if !datav.IsValid() {
			return nil
		}
		return badtype("slice", data)
	}
	sliceLen := datav.Len()
	if sliceLen != rv.Len() {
		return e("expected array length %d; got TOML array of length %d",
			rv.Len(), sliceLen)
	}
	return md.unifySliceArray(datav, rv)
}

func (md *MetaData) unifySlice(data interface{}, rv reflect.Value) error {
	datav := reflect.ValueOf(data)
	if datav.Kind() != reflect.Slice {
		if !datav.IsValid() {
			return nil
		}
		return badtype("slice", data)
	}
	n := datav.Len()
	if rv.IsNil() || rv.Cap() < n {
		rv.Set(reflect.MakeSlice(rv.Type(), n, n))
	}
	rv.SetLen(n)
	return md.unifySliceArray(datav, rv)
}

func (md *MetaData) unifySliceArray(data, rv reflect.Value) error {
	sliceLen := data.Len()
	for i := 0; i < sliceLen; i++ {
		v := data.Index(i).Interface()
		sliceval := indirect(rv.Index(i))
		if err := md.unify(v, sliceval); err != nil {
			return err
		}
	}
	return nil
}

func (md *MetaData) unifyDatetime(data interface{}, rv reflect.Value) error {
	if _, ok := data.(time.Time); ok {
		rv.Set(reflect.ValueOf(data))
		return nil
	}
	return badtype("time.Time", data)
}

func (md *MetaData) unifyString(data interface{}, rv reflect.Value) error {
	if s, ok := data.(string); ok {
		rv.SetString(s)
		return nil
	}
	return badtype("string", data)
}

func (md *MetaData) unifyFloat64(data interface{}, rv reflect.Value) error {
	if num, ok := data.(float64); ok {
		switch rv.Kind() {
		case reflect.Float32:
			fallthrough
		case reflect.Float64:
			rv.SetFloat(num)
		default:
			panic("bug")
		}
		return nil
	}
	return badtype("float", data)
}

func (md *MetaData) unifyInt(data interface{}, rv reflect.Value) error {
	if num, ok := data.(int64); ok {
		if rv.Kind() >= reflect.Int && rv.Kind() <= reflect.Int64 {
			switch rv.Kind() {
			case reflect.Int, reflect.Int64:
				// No bounds checking necessary.
			case reflect.Int8:
				if num < math.MinInt8 || num > math.MaxInt8 {
					return e("value %d is out of range for int8", num)
				}
			case reflect.Int16:
				if num < math.MinInt16 || num > math.MaxInt16 {
					return e("value %d is out of range for int16", num)
				}
			case reflect.Int32:
				if num < math.MinInt32 || num > math.MaxInt32 {
					return e("value %d is out of range for int32", num)
				}
			}
			rv.SetInt(num)
		} else if rv.Kind() >= reflect.Uint && rv.Kind() <= reflect.Uint64 {
			unum := uint64(num)
			switch rv.Kind() {
			case reflect.Uint, reflect.Uint64:
				// No bounds checking necessary.
			case reflect.Uint8:
				if num < 0 || unum > math.MaxUint8 {
					return e("value %d is out of range for uint8", num)
				}
			case reflect.Uint16:
				if num < 0 || unum > math.MaxUint16 {
					return e("value %d is out of range for uint16", num)
				}
			case reflect.Uint32:
				if num < 0 || unum > math.MaxUint32 {
					return e("value %d is out of range for uint32", num)
				}
			}
			rv.SetUint(unum)
		} else {
			panic("unreachable")
		}
		return nil
	}
	return badtype("integer", data)
}

func (md *MetaData) unifyBool(data interface{}, rv reflect.Value) error {
	if b, ok := data.(bool); ok {
		rv.SetBool(b)
		return nil
	}
	return badtype("boolean", data)
}

func (md *MetaData) unifyAnything(data interface{}, rv reflect.Value) error {
	rv.Set(reflect.ValueOf(data))
	return nil
}

func (md *MetaData) unifyText(data interface{}, v TextUnmarshaler) error {
	var s string
	switch sdata := data.(type) {
	case TextMarshaler:
		text, err := sdata.MarshalText()
		if err != nil {
			return err
		}
		s = string(text)
	case fmt.Stringer:
		s = sdata.String()
	case string:
		s = sdata
	case bool:
		s = fmt.Sprintf("%v", sdata)
	case int64:
		s = fmt.Sprintf("%d", sdata)
	case float64:
		s = fmt.Sprintf("%f", sdata)
	default:
		return badtype("primitive (string-like)", data)
	}
	if err := v.UnmarshalText([]byte(s)); err != nil {
		return err
	}
	return nil
}

// rvalue returns a reflect.Value of `v`. All pointers are resolved.
func rvalue(v interface{}) reflect.Value {
	return indirect(reflect.ValueOf(v))
}

// indirect returns the value pointed to by a pointer.
// Pointers are followed until the value is not a pointer.
// New values are allocated for each nil pointer.
//
// An exception to this rule is if the value satisfies an interface of
// interest to us (like encoding.TextUnmarshaler).
func indirect(v reflect.Value) reflect.Value {
	if v.Kind() != reflect.Ptr {
		if v.CanSet() {
			pv := v.Addr()
			if _, ok := pv.Interface().(TextUnmarshaler); ok {
				return pv
			}
		}
		return v
	}
	if v.IsNil() {
		v.Set(reflect.New(v.Type().Elem()))
	}
	return indirect(reflect.Indirect(v))
}

func isUnifiable(rv reflect.Value) bool {
	if rv.CanSet() {
		return true
	}
	if _, ok := rv.Interface().(TextUnmarshaler); ok {
		return true
	}
	return false
}

func badtype(expected string, data interface{}) error {
	return e("cannot load TOML value of type %T into a Go %s", data, expected)
}