summaryrefslogtreecommitdiff
path: root/vendor/k8s.io/apimachinery/pkg/runtime/converter.go
blob: 80343081f52d137b91ef6e49f743b1bd1e8db389 (plain)
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
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
/*
Copyright 2017 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package runtime

import (
	"bytes"
	encodingjson "encoding/json"
	"fmt"
	"math"
	"os"
	"reflect"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"time"

	"k8s.io/apimachinery/pkg/conversion"
	"k8s.io/apimachinery/pkg/util/json"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"

	"k8s.io/klog"
)

// UnstructuredConverter is an interface for converting between interface{}
// and map[string]interface representation.
type UnstructuredConverter interface {
	ToUnstructured(obj interface{}) (map[string]interface{}, error)
	FromUnstructured(u map[string]interface{}, obj interface{}) error
}

type structField struct {
	structType reflect.Type
	field      int
}

type fieldInfo struct {
	name      string
	nameValue reflect.Value
	omitempty bool
}

type fieldsCacheMap map[structField]*fieldInfo

type fieldsCache struct {
	sync.Mutex
	value atomic.Value
}

func newFieldsCache() *fieldsCache {
	cache := &fieldsCache{}
	cache.value.Store(make(fieldsCacheMap))
	return cache
}

var (
	marshalerType          = reflect.TypeOf(new(encodingjson.Marshaler)).Elem()
	unmarshalerType        = reflect.TypeOf(new(encodingjson.Unmarshaler)).Elem()
	mapStringInterfaceType = reflect.TypeOf(map[string]interface{}{})
	stringType             = reflect.TypeOf(string(""))
	int64Type              = reflect.TypeOf(int64(0))
	float64Type            = reflect.TypeOf(float64(0))
	boolType               = reflect.TypeOf(bool(false))
	fieldCache             = newFieldsCache()

	// DefaultUnstructuredConverter performs unstructured to Go typed object conversions.
	DefaultUnstructuredConverter = &unstructuredConverter{
		mismatchDetection: parseBool(os.Getenv("KUBE_PATCH_CONVERSION_DETECTOR")),
		comparison: conversion.EqualitiesOrDie(
			func(a, b time.Time) bool {
				return a.UTC() == b.UTC()
			},
		),
	}
)

func parseBool(key string) bool {
	if len(key) == 0 {
		return false
	}
	value, err := strconv.ParseBool(key)
	if err != nil {
		utilruntime.HandleError(fmt.Errorf("Couldn't parse '%s' as bool for unstructured mismatch detection", key))
	}
	return value
}

// unstructuredConverter knows how to convert between interface{} and
// Unstructured in both ways.
type unstructuredConverter struct {
	// If true, we will be additionally running conversion via json
	// to ensure that the result is true.
	// This is supposed to be set only in tests.
	mismatchDetection bool
	// comparison is the default test logic used to compare
	comparison conversion.Equalities
}

// NewTestUnstructuredConverter creates an UnstructuredConverter that accepts JSON typed maps and translates them
// to Go types via reflection. It performs mismatch detection automatically and is intended for use by external
// test tools. Use DefaultUnstructuredConverter if you do not explicitly need mismatch detection.
func NewTestUnstructuredConverter(comparison conversion.Equalities) UnstructuredConverter {
	return &unstructuredConverter{
		mismatchDetection: true,
		comparison:        comparison,
	}
}

// FromUnstructured converts an object from map[string]interface{} representation into a concrete type.
// It uses encoding/json/Unmarshaler if object implements it or reflection if not.
func (c *unstructuredConverter) FromUnstructured(u map[string]interface{}, obj interface{}) error {
	t := reflect.TypeOf(obj)
	value := reflect.ValueOf(obj)
	if t.Kind() != reflect.Ptr || value.IsNil() {
		return fmt.Errorf("FromUnstructured requires a non-nil pointer to an object, got %v", t)
	}
	err := fromUnstructured(reflect.ValueOf(u), value.Elem())
	if c.mismatchDetection {
		newObj := reflect.New(t.Elem()).Interface()
		newErr := fromUnstructuredViaJSON(u, newObj)
		if (err != nil) != (newErr != nil) {
			klog.Fatalf("FromUnstructured unexpected error for %v: error: %v", u, err)
		}
		if err == nil && !c.comparison.DeepEqual(obj, newObj) {
			klog.Fatalf("FromUnstructured mismatch\nobj1: %#v\nobj2: %#v", obj, newObj)
		}
	}
	return err
}

func fromUnstructuredViaJSON(u map[string]interface{}, obj interface{}) error {
	data, err := json.Marshal(u)
	if err != nil {
		return err
	}
	return json.Unmarshal(data, obj)
}

func fromUnstructured(sv, dv reflect.Value) error {
	sv = unwrapInterface(sv)
	if !sv.IsValid() {
		dv.Set(reflect.Zero(dv.Type()))
		return nil
	}
	st, dt := sv.Type(), dv.Type()

	switch dt.Kind() {
	case reflect.Map, reflect.Slice, reflect.Ptr, reflect.Struct, reflect.Interface:
		// Those require non-trivial conversion.
	default:
		// This should handle all simple types.
		if st.AssignableTo(dt) {
			dv.Set(sv)
			return nil
		}
		// We cannot simply use "ConvertibleTo", as JSON doesn't support conversions
		// between those four groups: bools, integers, floats and string. We need to
		// do the same.
		if st.ConvertibleTo(dt) {
			switch st.Kind() {
			case reflect.String:
				switch dt.Kind() {
				case reflect.String:
					dv.Set(sv.Convert(dt))
					return nil
				}
			case reflect.Bool:
				switch dt.Kind() {
				case reflect.Bool:
					dv.Set(sv.Convert(dt))
					return nil
				}
			case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
				reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
				switch dt.Kind() {
				case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
					reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
					dv.Set(sv.Convert(dt))
					return nil
				}
			case reflect.Float32, reflect.Float64:
				switch dt.Kind() {
				case reflect.Float32, reflect.Float64:
					dv.Set(sv.Convert(dt))
					return nil
				}
				if sv.Float() == math.Trunc(sv.Float()) {
					dv.Set(sv.Convert(dt))
					return nil
				}
			}
			return fmt.Errorf("cannot convert %s to %s", st.String(), dt.String())
		}
	}

	// Check if the object has a custom JSON marshaller/unmarshaller.
	if reflect.PtrTo(dt).Implements(unmarshalerType) {
		data, err := json.Marshal(sv.Interface())
		if err != nil {
			return fmt.Errorf("error encoding %s to json: %v", st.String(), err)
		}
		unmarshaler := dv.Addr().Interface().(encodingjson.Unmarshaler)
		return unmarshaler.UnmarshalJSON(data)
	}

	switch dt.Kind() {
	case reflect.Map:
		return mapFromUnstructured(sv, dv)
	case reflect.Slice:
		return sliceFromUnstructured(sv, dv)
	case reflect.Ptr:
		return pointerFromUnstructured(sv, dv)
	case reflect.Struct:
		return structFromUnstructured(sv, dv)
	case reflect.Interface:
		return interfaceFromUnstructured(sv, dv)
	default:
		return fmt.Errorf("unrecognized type: %v", dt.Kind())
	}
}

func fieldInfoFromField(structType reflect.Type, field int) *fieldInfo {
	fieldCacheMap := fieldCache.value.Load().(fieldsCacheMap)
	if info, ok := fieldCacheMap[structField{structType, field}]; ok {
		return info
	}

	// Cache miss - we need to compute the field name.
	info := &fieldInfo{}
	typeField := structType.Field(field)
	jsonTag := typeField.Tag.Get("json")
	if len(jsonTag) == 0 {
		// Make the first character lowercase.
		if typeField.Name == "" {
			info.name = typeField.Name
		} else {
			info.name = strings.ToLower(typeField.Name[:1]) + typeField.Name[1:]
		}
	} else {
		items := strings.Split(jsonTag, ",")
		info.name = items[0]
		for i := range items {
			if items[i] == "omitempty" {
				info.omitempty = true
			}
		}
	}
	info.nameValue = reflect.ValueOf(info.name)

	fieldCache.Lock()
	defer fieldCache.Unlock()
	fieldCacheMap = fieldCache.value.Load().(fieldsCacheMap)
	newFieldCacheMap := make(fieldsCacheMap)
	for k, v := range fieldCacheMap {
		newFieldCacheMap[k] = v
	}
	newFieldCacheMap[structField{structType, field}] = info
	fieldCache.value.Store(newFieldCacheMap)
	return info
}

func unwrapInterface(v reflect.Value) reflect.Value {
	for v.Kind() == reflect.Interface {
		v = v.Elem()
	}
	return v
}

func mapFromUnstructured(sv, dv reflect.Value) error {
	st, dt := sv.Type(), dv.Type()
	if st.Kind() != reflect.Map {
		return fmt.Errorf("cannot restore map from %v", st.Kind())
	}

	if !st.Key().AssignableTo(dt.Key()) && !st.Key().ConvertibleTo(dt.Key()) {
		return fmt.Errorf("cannot copy map with non-assignable keys: %v %v", st.Key(), dt.Key())
	}

	if sv.IsNil() {
		dv.Set(reflect.Zero(dt))
		return nil
	}
	dv.Set(reflect.MakeMap(dt))
	for _, key := range sv.MapKeys() {
		value := reflect.New(dt.Elem()).Elem()
		if val := unwrapInterface(sv.MapIndex(key)); val.IsValid() {
			if err := fromUnstructured(val, value); err != nil {
				return err
			}
		} else {
			value.Set(reflect.Zero(dt.Elem()))
		}
		if st.Key().AssignableTo(dt.Key()) {
			dv.SetMapIndex(key, value)
		} else {
			dv.SetMapIndex(key.Convert(dt.Key()), value)
		}
	}
	return nil
}

func sliceFromUnstructured(sv, dv reflect.Value) error {
	st, dt := sv.Type(), dv.Type()
	if st.Kind() == reflect.String && dt.Elem().Kind() == reflect.Uint8 {
		// We store original []byte representation as string.
		// This conversion is allowed, but we need to be careful about
		// marshaling data appropriately.
		if len(sv.Interface().(string)) > 0 {
			marshalled, err := json.Marshal(sv.Interface())
			if err != nil {
				return fmt.Errorf("error encoding %s to json: %v", st, err)
			}
			// TODO: Is this Unmarshal needed?
			var data []byte
			err = json.Unmarshal(marshalled, &data)
			if err != nil {
				return fmt.Errorf("error decoding from json: %v", err)
			}
			dv.SetBytes(data)
		} else {
			dv.Set(reflect.Zero(dt))
		}
		return nil
	}
	if st.Kind() != reflect.Slice {
		return fmt.Errorf("cannot restore slice from %v", st.Kind())
	}

	if sv.IsNil() {
		dv.Set(reflect.Zero(dt))
		return nil
	}
	dv.Set(reflect.MakeSlice(dt, sv.Len(), sv.Cap()))
	for i := 0; i < sv.Len(); i++ {
		if err := fromUnstructured(sv.Index(i), dv.Index(i)); err != nil {
			return err
		}
	}
	return nil
}

func pointerFromUnstructured(sv, dv reflect.Value) error {
	st, dt := sv.Type(), dv.Type()

	if st.Kind() == reflect.Ptr && sv.IsNil() {
		dv.Set(reflect.Zero(dt))
		return nil
	}
	dv.Set(reflect.New(dt.Elem()))
	switch st.Kind() {
	case reflect.Ptr, reflect.Interface:
		return fromUnstructured(sv.Elem(), dv.Elem())
	default:
		return fromUnstructured(sv, dv.Elem())
	}
}

func structFromUnstructured(sv, dv reflect.Value) error {
	st, dt := sv.Type(), dv.Type()
	if st.Kind() != reflect.Map {
		return fmt.Errorf("cannot restore struct from: %v", st.Kind())
	}

	for i := 0; i < dt.NumField(); i++ {
		fieldInfo := fieldInfoFromField(dt, i)
		fv := dv.Field(i)

		if len(fieldInfo.name) == 0 {
			// This field is inlined.
			if err := fromUnstructured(sv, fv); err != nil {
				return err
			}
		} else {
			value := unwrapInterface(sv.MapIndex(fieldInfo.nameValue))
			if value.IsValid() {
				if err := fromUnstructured(value, fv); err != nil {
					return err
				}
			} else {
				fv.Set(reflect.Zero(fv.Type()))
			}
		}
	}
	return nil
}

func interfaceFromUnstructured(sv, dv reflect.Value) error {
	// TODO: Is this conversion safe?
	dv.Set(sv)
	return nil
}

// ToUnstructured converts an object into map[string]interface{} representation.
// It uses encoding/json/Marshaler if object implements it or reflection if not.
func (c *unstructuredConverter) ToUnstructured(obj interface{}) (map[string]interface{}, error) {
	var u map[string]interface{}
	var err error
	if unstr, ok := obj.(Unstructured); ok {
		u = unstr.UnstructuredContent()
	} else {
		t := reflect.TypeOf(obj)
		value := reflect.ValueOf(obj)
		if t.Kind() != reflect.Ptr || value.IsNil() {
			return nil, fmt.Errorf("ToUnstructured requires a non-nil pointer to an object, got %v", t)
		}
		u = map[string]interface{}{}
		err = toUnstructured(value.Elem(), reflect.ValueOf(&u).Elem())
	}
	if c.mismatchDetection {
		newUnstr := map[string]interface{}{}
		newErr := toUnstructuredViaJSON(obj, &newUnstr)
		if (err != nil) != (newErr != nil) {
			klog.Fatalf("ToUnstructured unexpected error for %v: error: %v; newErr: %v", obj, err, newErr)
		}
		if err == nil && !c.comparison.DeepEqual(u, newUnstr) {
			klog.Fatalf("ToUnstructured mismatch\nobj1: %#v\nobj2: %#v", u, newUnstr)
		}
	}
	if err != nil {
		return nil, err
	}
	return u, nil
}

// DeepCopyJSON deep copies the passed value, assuming it is a valid JSON representation i.e. only contains
// types produced by json.Unmarshal() and also int64.
// bool, int64, float64, string, []interface{}, map[string]interface{}, json.Number and nil
func DeepCopyJSON(x map[string]interface{}) map[string]interface{} {
	return DeepCopyJSONValue(x).(map[string]interface{})
}

// DeepCopyJSONValue deep copies the passed value, assuming it is a valid JSON representation i.e. only contains
// types produced by json.Unmarshal() and also int64.
// bool, int64, float64, string, []interface{}, map[string]interface{}, json.Number and nil
func DeepCopyJSONValue(x interface{}) interface{} {
	switch x := x.(type) {
	case map[string]interface{}:
		if x == nil {
			// Typed nil - an interface{} that contains a type map[string]interface{} with a value of nil
			return x
		}
		clone := make(map[string]interface{}, len(x))
		for k, v := range x {
			clone[k] = DeepCopyJSONValue(v)
		}
		return clone
	case []interface{}:
		if x == nil {
			// Typed nil - an interface{} that contains a type []interface{} with a value of nil
			return x
		}
		clone := make([]interface{}, len(x))
		for i, v := range x {
			clone[i] = DeepCopyJSONValue(v)
		}
		return clone
	case string, int64, bool, float64, nil, encodingjson.Number:
		return x
	default:
		panic(fmt.Errorf("cannot deep copy %T", x))
	}
}

func toUnstructuredViaJSON(obj interface{}, u *map[string]interface{}) error {
	data, err := json.Marshal(obj)
	if err != nil {
		return err
	}
	return json.Unmarshal(data, u)
}

var (
	nullBytes  = []byte("null")
	trueBytes  = []byte("true")
	falseBytes = []byte("false")
)

func getMarshaler(v reflect.Value) (encodingjson.Marshaler, bool) {
	// Check value receivers if v is not a pointer and pointer receivers if v is a pointer
	if v.Type().Implements(marshalerType) {
		return v.Interface().(encodingjson.Marshaler), true
	}
	// Check pointer receivers if v is not a pointer
	if v.Kind() != reflect.Ptr && v.CanAddr() {
		v = v.Addr()
		if v.Type().Implements(marshalerType) {
			return v.Interface().(encodingjson.Marshaler), true
		}
	}
	return nil, false
}

func toUnstructured(sv, dv reflect.Value) error {
	// Check if the object has a custom JSON marshaller/unmarshaller.
	if marshaler, ok := getMarshaler(sv); ok {
		if sv.Kind() == reflect.Ptr && sv.IsNil() {
			// We're done - we don't need to store anything.
			return nil
		}

		data, err := marshaler.MarshalJSON()
		if err != nil {
			return err
		}
		switch {
		case len(data) == 0:
			return fmt.Errorf("error decoding from json: empty value")

		case bytes.Equal(data, nullBytes):
			// We're done - we don't need to store anything.

		case bytes.Equal(data, trueBytes):
			dv.Set(reflect.ValueOf(true))

		case bytes.Equal(data, falseBytes):
			dv.Set(reflect.ValueOf(false))

		case data[0] == '"':
			var result string
			err := json.Unmarshal(data, &result)
			if err != nil {
				return fmt.Errorf("error decoding string from json: %v", err)
			}
			dv.Set(reflect.ValueOf(result))

		case data[0] == '{':
			result := make(map[string]interface{})
			err := json.Unmarshal(data, &result)
			if err != nil {
				return fmt.Errorf("error decoding object from json: %v", err)
			}
			dv.Set(reflect.ValueOf(result))

		case data[0] == '[':
			result := make([]interface{}, 0)
			err := json.Unmarshal(data, &result)
			if err != nil {
				return fmt.Errorf("error decoding array from json: %v", err)
			}
			dv.Set(reflect.ValueOf(result))

		default:
			var (
				resultInt   int64
				resultFloat float64
				err         error
			)
			if err = json.Unmarshal(data, &resultInt); err == nil {
				dv.Set(reflect.ValueOf(resultInt))
			} else if err = json.Unmarshal(data, &resultFloat); err == nil {
				dv.Set(reflect.ValueOf(resultFloat))
			} else {
				return fmt.Errorf("error decoding number from json: %v", err)
			}
		}

		return nil
	}

	st, dt := sv.Type(), dv.Type()
	switch st.Kind() {
	case reflect.String:
		if dt.Kind() == reflect.Interface && dv.NumMethod() == 0 {
			dv.Set(reflect.New(stringType))
		}
		dv.Set(reflect.ValueOf(sv.String()))
		return nil
	case reflect.Bool:
		if dt.Kind() == reflect.Interface && dv.NumMethod() == 0 {
			dv.Set(reflect.New(boolType))
		}
		dv.Set(reflect.ValueOf(sv.Bool()))
		return nil
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		if dt.Kind() == reflect.Interface && dv.NumMethod() == 0 {
			dv.Set(reflect.New(int64Type))
		}
		dv.Set(reflect.ValueOf(sv.Int()))
		return nil
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		uVal := sv.Uint()
		if uVal > math.MaxInt64 {
			return fmt.Errorf("unsigned value %d does not fit into int64 (overflow)", uVal)
		}
		if dt.Kind() == reflect.Interface && dv.NumMethod() == 0 {
			dv.Set(reflect.New(int64Type))
		}
		dv.Set(reflect.ValueOf(int64(uVal)))
		return nil
	case reflect.Float32, reflect.Float64:
		if dt.Kind() == reflect.Interface && dv.NumMethod() == 0 {
			dv.Set(reflect.New(float64Type))
		}
		dv.Set(reflect.ValueOf(sv.Float()))
		return nil
	case reflect.Map:
		return mapToUnstructured(sv, dv)
	case reflect.Slice:
		return sliceToUnstructured(sv, dv)
	case reflect.Ptr:
		return pointerToUnstructured(sv, dv)
	case reflect.Struct:
		return structToUnstructured(sv, dv)
	case reflect.Interface:
		return interfaceToUnstructured(sv, dv)
	default:
		return fmt.Errorf("unrecognized type: %v", st.Kind())
	}
}

func mapToUnstructured(sv, dv reflect.Value) error {
	st, dt := sv.Type(), dv.Type()
	if sv.IsNil() {
		dv.Set(reflect.Zero(dt))
		return nil
	}
	if dt.Kind() == reflect.Interface && dv.NumMethod() == 0 {
		if st.Key().Kind() == reflect.String {
			switch st.Elem().Kind() {
			// TODO It should be possible to reuse the slice for primitive types.
			// However, it is panicing in the following form.
			// case reflect.String, reflect.Bool,
			// 	reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
			// 	reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
			// 	sv.Set(sv)
			// 	return nil
			default:
				// We need to do a proper conversion.
			}
		}
		dv.Set(reflect.MakeMap(mapStringInterfaceType))
		dv = dv.Elem()
		dt = dv.Type()
	}
	if dt.Kind() != reflect.Map {
		return fmt.Errorf("cannot convert struct to: %v", dt.Kind())
	}

	if !st.Key().AssignableTo(dt.Key()) && !st.Key().ConvertibleTo(dt.Key()) {
		return fmt.Errorf("cannot copy map with non-assignable keys: %v %v", st.Key(), dt.Key())
	}

	for _, key := range sv.MapKeys() {
		value := reflect.New(dt.Elem()).Elem()
		if err := toUnstructured(sv.MapIndex(key), value); err != nil {
			return err
		}
		if st.Key().AssignableTo(dt.Key()) {
			dv.SetMapIndex(key, value)
		} else {
			dv.SetMapIndex(key.Convert(dt.Key()), value)
		}
	}
	return nil
}

func sliceToUnstructured(sv, dv reflect.Value) error {
	st, dt := sv.Type(), dv.Type()
	if sv.IsNil() {
		dv.Set(reflect.Zero(dt))
		return nil
	}
	if st.Elem().Kind() == reflect.Uint8 {
		dv.Set(reflect.New(stringType))
		data, err := json.Marshal(sv.Bytes())
		if err != nil {
			return err
		}
		var result string
		if err = json.Unmarshal(data, &result); err != nil {
			return err
		}
		dv.Set(reflect.ValueOf(result))
		return nil
	}
	if dt.Kind() == reflect.Interface && dv.NumMethod() == 0 {
		switch st.Elem().Kind() {
		// TODO It should be possible to reuse the slice for primitive types.
		// However, it is panicing in the following form.
		// case reflect.String, reflect.Bool,
		// 	reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
		// 	reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		// 	sv.Set(sv)
		// 	return nil
		default:
			// We need to do a proper conversion.
			dv.Set(reflect.MakeSlice(reflect.SliceOf(dt), sv.Len(), sv.Cap()))
			dv = dv.Elem()
			dt = dv.Type()
		}
	}
	if dt.Kind() != reflect.Slice {
		return fmt.Errorf("cannot convert slice to: %v", dt.Kind())
	}
	for i := 0; i < sv.Len(); i++ {
		if err := toUnstructured(sv.Index(i), dv.Index(i)); err != nil {
			return err
		}
	}
	return nil
}

func pointerToUnstructured(sv, dv reflect.Value) error {
	if sv.IsNil() {
		// We're done - we don't need to store anything.
		return nil
	}
	return toUnstructured(sv.Elem(), dv)
}

func isZero(v reflect.Value) bool {
	switch v.Kind() {
	case reflect.Array, 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:
		return v.Uint() == 0
	case reflect.Float32, reflect.Float64:
		return v.Float() == 0
	case reflect.Map, reflect.Slice:
		// TODO: It seems that 0-len maps are ignored in it.
		return v.IsNil() || v.Len() == 0
	case reflect.Ptr, reflect.Interface:
		return v.IsNil()
	}
	return false
}

func structToUnstructured(sv, dv reflect.Value) error {
	st, dt := sv.Type(), dv.Type()
	if dt.Kind() == reflect.Interface && dv.NumMethod() == 0 {
		dv.Set(reflect.MakeMapWithSize(mapStringInterfaceType, st.NumField()))
		dv = dv.Elem()
		dt = dv.Type()
	}
	if dt.Kind() != reflect.Map {
		return fmt.Errorf("cannot convert struct to: %v", dt.Kind())
	}
	realMap := dv.Interface().(map[string]interface{})

	for i := 0; i < st.NumField(); i++ {
		fieldInfo := fieldInfoFromField(st, i)
		fv := sv.Field(i)

		if fieldInfo.name == "-" {
			// This field should be skipped.
			continue
		}
		if fieldInfo.omitempty && isZero(fv) {
			// omitempty fields should be ignored.
			continue
		}
		if len(fieldInfo.name) == 0 {
			// This field is inlined.
			if err := toUnstructured(fv, dv); err != nil {
				return err
			}
			continue
		}
		switch fv.Type().Kind() {
		case reflect.String:
			realMap[fieldInfo.name] = fv.String()
		case reflect.Bool:
			realMap[fieldInfo.name] = fv.Bool()
		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
			realMap[fieldInfo.name] = fv.Int()
		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
			realMap[fieldInfo.name] = fv.Uint()
		case reflect.Float32, reflect.Float64:
			realMap[fieldInfo.name] = fv.Float()
		default:
			subv := reflect.New(dt.Elem()).Elem()
			if err := toUnstructured(fv, subv); err != nil {
				return err
			}
			dv.SetMapIndex(fieldInfo.nameValue, subv)
		}
	}
	return nil
}

func interfaceToUnstructured(sv, dv reflect.Value) error {
	if !sv.IsValid() || sv.IsNil() {
		dv.Set(reflect.Zero(dv.Type()))
		return nil
	}
	return toUnstructured(sv.Elem(), dv)
}