-
Notifications
You must be signed in to change notification settings - Fork 0
/
impl.go
591 lines (535 loc) · 16.1 KB
/
impl.go
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
package fig
import (
"errors"
"fmt"
"os"
"reflect"
"strconv"
"strings"
)
type Qualifier interface {
Qualify() string
}
const (
// fig tag itself
FIG_TAG = "fig"
// configurations for fig tag
IMPL_TAG_KEY = "impl"
ENV_TAG_KEY = "env"
SKIP_TAG_KEY = "skip"
REG_TAG_KEY = "reg"
QUAL_TAG_KEY = "qual"
SIZE_TAG_KEY = "size"
CAPACITY_TAG_KEY = "cap"
)
type Fig struct {
injectOnlyIfFigTagProvided bool
registered map[reflect.Type]interface{}
assembled map[reflect.Type]bool
registeredValues map[string]interface{}
}
func New(injectOnlyIfFigTagProvided bool) *Fig {
return &Fig{
injectOnlyIfFigTagProvided: injectOnlyIfFigTagProvided,
registered: make(map[reflect.Type]interface{}),
assembled: make(map[reflect.Type]bool),
registeredValues: make(map[string]interface{}),
}
}
var (
ErrorCannotBeRegistered = errors.New("provided value can't be registered")
ErrorCannotBeHolder = errors.New("provided value can't be holder")
ErrorCannotDecideImplementation = errors.New("not able to get value to inject")
ErrorRegisteredValueOverridden = errors.New("already registered value was overridden")
ErrorIncorrectTagConfiguration = errors.New("invalid `fig` tag configuration")
)
type FigError struct {
Error_ error
Cause string
}
func (fe FigError) Error() string {
return fmt.Sprintf("Message: %s. Cause: %s", fe.Cause, fe.Error_.Error())
}
func (fig *Fig) Register(impls ...interface{}) error {
// Crowdbotics
for _, impl := range impls {
implType := reflect.TypeOf(impl)
if implType == nil {
return FigError{Cause: "nil cannot be registered as injectable value", Error_: ErrorCannotBeRegistered}
}
if implType.Kind() == reflect.Struct ||
implType.Kind() == reflect.Ptr && implType.Elem().Kind() == reflect.Struct {
fig.registered[implType] = impl
} else {
return FigError{Cause: "only structs and references to structs can be registered", Error_: ErrorCannotBeRegistered}
}
}
return nil
}
func (fig *Fig) RegisterValue(key string, value interface{}) error {
if value == nil {
return FigError{
Cause: "nil reference is not allowed",
Error_: ErrorCannotBeRegistered,
}
}
if _, found := fig.registeredValues[key]; found {
fig.registeredValues[key] = value
return FigError{
Error_: ErrorRegisteredValueOverridden,
}
}
fig.registeredValues[key] = value
return nil
}
func (fig *Fig) RegisterValues(keyValues map[string]interface{}) error {
for key, value := range keyValues {
if err := fig.RegisterValue(key, value); err != nil {
return err
}
}
return nil
}
func (fig *Fig) Initialize(holder interface{}) error {
assemblingChain := make([]string, 0)
err := fig.initialize(holder, &assemblingChain)
if err != nil {
if len(assemblingChain) > 0 {
figErr := err.(FigError)
figErr.Cause = strings.Join(assemblingChain, " -> ") + "=> " + figErr.Cause
return figErr
}
return err
}
return nil
}
func (fig *Fig) initialize(holder interface{}, assemblingChain *[]string) error {
holderType := reflect.TypeOf(holder)
if holderType == nil {
return FigError{Cause: "nil cannot be holder", Error_: ErrorCannotBeHolder}
}
if holderType.Kind() != reflect.Ptr ||
holderType.Elem().Kind() != reflect.Struct {
return FigError{
Cause: fmt.Sprintf("Only references to structs can be holders: %v", holderType),
Error_: ErrorCannotBeHolder,
}
}
if err := fig.AssembleRegistered(assemblingChain); err != nil {
return err
}
return fig.assemble(holder, assemblingChain, false)
}
func (fig *Fig) AssembleRegistered(assemblingChain *[]string) error {
for regType, regObject := range fig.registered {
if !fig.assembled[regType] {
fig.assembled[regType] = true
if err := fig.assemble(regObject, assemblingChain, true); err != nil {
return err
}
}
}
return nil
}
func getFigTagConfig(tag reflect.StructTag, key string) (string, bool, error) {
if figTag, ok := tag.Lookup(FIG_TAG); ok {
return getConfigValueForKey(figTag, key)
} else {
return "", false, nil
}
}
func getConfigValueForKey(conf string, key string) (string, bool, error) {
confHolder := key + "["
keyStart := strings.Index(conf, confHolder)
if keyStart < 0 {
return "", false, nil
}
valStart := keyStart + len(confHolder)
valEnd := strings.Index(conf[valStart:], "]")
if valEnd <= 0 {
return "", false, FigError{
Cause: "Invalid configuration in: " + conf + " for configuration: " + key,
Error_: ErrorIncorrectTagConfiguration,
}
}
return string(conf[valStart : valStart+valEnd]), true, nil
}
func setByImplConf(canBeSet []interface{}, elementField reflect.Value, implFigConf string) error {
for _, canBe := range canBeSet {
implName := getFullName(canBe)
if implName == implFigConf {
elementField.Addr().Elem().Set(reflect.ValueOf(canBe))
return nil
}
}
return FigError{
Cause: fmt.Sprintf("Implementation defined in tag was not found: %s", implFigConf),
Error_: ErrorCannotDecideImplementation,
}
}
func setByQualConf(canBeSet []interface{}, elementField reflect.Value, qualFigConf string) error {
for _, canBe := range canBeSet {
if checkQualifier(canBe, qualFigConf) {
elementField.Addr().Elem().Set(reflect.ValueOf(canBe))
return nil
}
}
return FigError{
Cause: fmt.Sprintf("Condition defined in tag was not found: %s", qualFigConf),
Error_: ErrorCannotDecideImplementation,
}
}
func (fig *Fig) setFoundImpl(canBeSet []interface{}, elementField reflect.Value, tag reflect.StructTag, assemblingChain *[]string) error {
switch {
case len(canBeSet) > 1:
if implFigConf, found, err := getFigTagConfig(tag, IMPL_TAG_KEY); err != nil {
return err
} else if found {
return setByImplConf(canBeSet, elementField, implFigConf)
} else if qualFigConf, found, err := getFigTagConfig(tag, QUAL_TAG_KEY); err != nil {
return err
} else if found {
return setByQualConf(canBeSet, elementField, qualFigConf)
} else {
mes := "Can't chose implementation for " + elementField.String() + ":\n"
for _, canBe := range canBeSet {
mes += fmt.Sprintf("\t%T\n", canBe)
}
return FigError{Cause: mes, Error_: ErrorCannotDecideImplementation}
}
case len(canBeSet) < 1:
switch elementField.Kind() {
case reflect.Ptr, reflect.Struct:
if elementField.Kind() == reflect.Ptr {
for elementField.Kind() == reflect.Ptr {
elementField.Set(reflect.New(elementField.Type().Elem()))
elementField = elementField.Elem()
}
elementField.Set(reflect.New(elementField.Type()).Elem())
}
if err := fig.initialize(elementField.Addr().Interface(), assemblingChain); err != nil {
return err
}
default:
return FigError{Cause: "No implementation found for " + elementField.String(), Error_: ErrorCannotDecideImplementation}
}
//switch elementField.Kind() {
//case reflect.Struct:
// if err := fig.Initialize(elementField.Addr().Interface()); err != nil {
// return err
// }
//case reflect.Ptr:
// if elementField.IsNil() {
// elementField.Set(reflect.New(elementField.Type().Elem()))
// }
// if err := fig.setFoundImpl(canBeSet, elementField, tag); err != nil {
// return err
// }
// //if err := fig.Initialize(elementField.Interface()); err != nil {
// // return err
// //}
//default:
// return FigError{Cause: "no implementation found for " + elementField.String(), Error_: ErrorCannotDecideImplementation}
//}
default:
elementField.Addr().Elem().Set(reflect.ValueOf(canBeSet[0]))
}
return nil
}
func checkQualifier(canBe interface{}, qualFigConf string) bool {
canBeType := reflect.TypeOf(canBe)
if canBeType.Implements(reflect.TypeOf((*Qualifier)(nil)).Elem()) {
if canBe.(Qualifier).Qualify() == qualFigConf {
return true
}
}
return false
}
func getFullName(canBe interface{}) string {
var implName string
var pckPath string
typeOfCanBe := reflect.TypeOf(canBe)
if typeOfCanBe.Kind() == reflect.Ptr && typeOfCanBe.Elem().Kind() == reflect.Struct {
pckPath = typeOfCanBe.Elem().PkgPath()
implName = typeOfCanBe.Elem().Name()
} else if typeOfCanBe.Kind() == reflect.Struct {
pckPath = typeOfCanBe.PkgPath()
implName = typeOfCanBe.Name()
} else {
return ""
}
if pckPath != "" {
implName = pckPath + "/" + implName
}
return implName
}
type InjectStep interface {
Do() error
Break() bool
}
type InjectStepValueSetup struct {
fig *Fig
holderElementField reflect.Value
tag reflect.StructTag
recursive bool
assemblingChain *[]string
}
func NewValueSetup(fig *Fig,
tag reflect.StructTag,
holderElementField reflect.Value,
recursive bool,
assemblingChain *[]string) *InjectStepValueSetup {
return &InjectStepValueSetup{
fig: fig,
holderElementField: holderElementField,
recursive: recursive,
tag: tag,
assemblingChain: assemblingChain,
}
}
func (valueSetup *InjectStepValueSetup) injectIf(condition func(l, r reflect.Type) bool) error {
var canBeSet []interface{}
for registeredType, injectableObj := range valueSetup.fig.registered {
if condition(registeredType, valueSetup.holderElementField.Type()) {
if valueSetup.recursive && !valueSetup.fig.assembled[registeredType] {
if err := valueSetup.fig.assemble(injectableObj, valueSetup.assemblingChain, valueSetup.recursive); err != nil {
return err
}
}
canBeSet = append(canBeSet, injectableObj)
}
}
if err := valueSetup.fig.setFoundImpl(canBeSet, valueSetup.holderElementField, valueSetup.tag, valueSetup.assemblingChain); err != nil {
return err
}
return nil
}
func (valueSetup *InjectStepValueSetup) Do() error {
switch valueSetup.holderElementField.Kind() {
case reflect.Interface:
if err := valueSetup.injectIf(func(l, r reflect.Type) bool {
return l.Implements(r)
}); err != nil {
return err
}
case reflect.Ptr, reflect.Struct:
if err := valueSetup.injectIf(func(l, r reflect.Type) bool {
return l.AssignableTo(r)
}); err != nil {
return err
}
case reflect.String:
if envKey, found, err := getFigTagConfig(valueSetup.tag, ENV_TAG_KEY); err != nil {
return err
} else if found {
envVal := os.Getenv(envKey)
valueSetup.holderElementField.Addr().Elem().Set(reflect.ValueOf(envVal))
}
case reflect.Map:
valueSetup.holderElementField.Set(
reflect.MakeMap(
reflect.MapOf(
valueSetup.holderElementField.Type().Key(),
valueSetup.holderElementField.Type().Elem(),
),
),
)
case reflect.Chan:
val, found, err := getFigTagConfig(valueSetup.tag, SIZE_TAG_KEY)
if err != nil {
return err
}
size := 1
if found {
if size, err = strconv.Atoi(val); err != nil {
return FigError{
Cause: "Size of channel must be int value: " + err.Error(),
Error_: ErrorIncorrectTagConfiguration,
}
}
}
valueSetup.holderElementField.Set(
reflect.MakeChan(
reflect.ChanOf(
reflect.BothDir,
valueSetup.holderElementField.Type().Elem(),
),
size,
),
)
case reflect.Slice:
size := 0
val, found, err := getFigTagConfig(valueSetup.tag, SIZE_TAG_KEY)
if err != nil {
return err
}
if found {
if size, err = strconv.Atoi(val); err != nil {
return FigError{
Cause: "Size of slice must be int value: " + err.Error(),
Error_: ErrorIncorrectTagConfiguration,
}
}
}
capacity := size
val, found, err = getFigTagConfig(valueSetup.tag, CAPACITY_TAG_KEY)
if err != nil {
return err
}
if found {
if capacity, err = strconv.Atoi(val); err != nil {
return FigError{
Cause: "Capacity of slice must be int value: " + err.Error(),
Error_: ErrorIncorrectTagConfiguration,
}
}
}
if size > capacity {
return FigError{
Cause: fmt.Sprintf("Size[%d] of slice can't be bigger than capacity[%d]", size, capacity),
Error_: ErrorIncorrectTagConfiguration,
}
}
valueSetup.holderElementField.Set(
reflect.MakeSlice(
reflect.SliceOf(
valueSetup.holderElementField.Type().Elem(),
),
size,
capacity,
),
)
//case
// reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
// reflect.Float32, reflect.Float64,
// reflect.Bool,
// reflect.Complex64, reflect.Complex128,
// reflect.Array,
// reflect.Func:
default:
return FigError{Cause: "Unsupported holder field type: " + valueSetup.holderElementField.String(), Error_: ErrorCannotBeHolder}
}
return nil
}
func (valueSetup *InjectStepValueSetup) Break() bool {
return true
}
type InjectStepRegisteredValueSetup struct {
fig *Fig
tag reflect.StructTag
holderElementField reflect.Value
skip bool
}
func NewRegisteredValueSetup(fig *Fig, tag reflect.StructTag, holderElementField reflect.Value) *InjectStepRegisteredValueSetup {
return &InjectStepRegisteredValueSetup{fig: fig, tag: tag, holderElementField: holderElementField}
}
func (registeredValue *InjectStepRegisteredValueSetup) Do() error {
if regKey, found, err := getFigTagConfig(registeredValue.tag, REG_TAG_KEY); err != nil {
return err
} else if found {
if regValue, found := registeredValue.fig.registeredValues[regKey]; found {
registeredValue.holderElementField.Addr().Elem().Set(reflect.ValueOf(regValue))
registeredValue.skip = true
} else {
return FigError{
Cause: fmt.Sprintf("Implementation was not found for: %s", registeredValue.holderElementField),
Error_: ErrorCannotDecideImplementation,
}
}
}
return nil
}
func (registeredValue *InjectStepRegisteredValueSetup) Break() bool {
return registeredValue.skip
}
type InjectStepFigTagRequiredCheck struct {
fig *Fig
tag reflect.StructTag
skip bool
}
func NewFigTagRequiredCheck(fig *Fig, tag reflect.StructTag) *InjectStepFigTagRequiredCheck {
return &InjectStepFigTagRequiredCheck{fig: fig, tag: tag}
}
func (figTagRequired *InjectStepFigTagRequiredCheck) Do() error {
if figTagRequired.fig.injectOnlyIfFigTagProvided {
if _, found := figTagRequired.tag.Lookup(FIG_TAG); !found {
figTagRequired.skip = true
}
}
return nil
}
func (figTagRequired *InjectStepFigTagRequiredCheck) Break() bool {
return figTagRequired.skip
}
type InjectStepSkipCheck struct {
tag reflect.StructTag
skip bool
}
func NewSkipCheck(tag reflect.StructTag) *InjectStepSkipCheck {
return &InjectStepSkipCheck{tag: tag}
}
func (skipVerify *InjectStepSkipCheck) Do() error {
if skipConfValue, found, err := getFigTagConfig(skipVerify.tag, SKIP_TAG_KEY); err != nil {
return err
} else if found {
if skipConfValue == "true" {
skipVerify.skip = true
} else if skipConfValue != "false" {
return FigError{
Cause: "Incorrectly defined configuration `skip` of `fig` tag. Supported values: true | false. Got: " + skipConfValue,
Error_: ErrorIncorrectTagConfiguration,
}
}
}
return nil
}
func (skipVerify *InjectStepSkipCheck) Break() bool {
return skipVerify.skip
}
type StepMachine struct {
steps []InjectStep
}
func NewStepMachine() *StepMachine {
return &StepMachine{}
}
func (sm *StepMachine) Add(steps ...InjectStep) *StepMachine {
sm.steps = append(sm.steps, steps...)
return sm
}
func (sm *StepMachine) Do() error {
for _, step := range sm.steps {
if err := step.Do(); err != nil {
return err
}
if step.Break() {
break
}
}
return nil
}
func (fig *Fig) assemble(holder interface{}, assemblingChain *[]string, recursive bool) error {
holderElement := reflect.ValueOf(holder)
if holderElement.Kind() == reflect.Ptr {
holderElement = holderElement.Elem()
}
holderElementType := holderElement.Type()
*assemblingChain = append(*assemblingChain, holderElementType.String())
numFields := holderElement.NumField()
for fieldIndex := 0; fieldIndex < numFields; fieldIndex++ {
holderElementField := holderElement.Field(fieldIndex)
tag := holderElementType.Field(fieldIndex).Tag
holderElementFieldType := holderElementField.Type()
*assemblingChain = append(*assemblingChain, holderElementFieldType.String())
if err := NewStepMachine().Add(
NewFigTagRequiredCheck(fig, tag),
NewSkipCheck(tag),
NewRegisteredValueSetup(fig, tag, holderElementField),
NewValueSetup(fig, tag, holderElementField, recursive, assemblingChain),
).Do(); err != nil {
return err
}
*assemblingChain = (*assemblingChain)[:len(*assemblingChain)-1]
}
*assemblingChain = (*assemblingChain)[:len(*assemblingChain)-1]
return nil
}