1// Copyright 2018 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package impl
6
7import (
8 "fmt"
9 "reflect"
10
11 "google.golang.org/protobuf/reflect/protoreflect"
12)
13
14// unwrapper unwraps the value to the underlying value.
15// This is implemented by List and Map.
16type unwrapper interface {
17 protoUnwrap() any
18}
19
20// A Converter coverts to/from Go reflect.Value types and protobuf protoreflect.Value types.
21type Converter interface {
22 // PBValueOf converts a reflect.Value to a protoreflect.Value.
23 PBValueOf(reflect.Value) protoreflect.Value
24
25 // GoValueOf converts a protoreflect.Value to a reflect.Value.
26 GoValueOf(protoreflect.Value) reflect.Value
27
28 // IsValidPB returns whether a protoreflect.Value is compatible with this type.
29 IsValidPB(protoreflect.Value) bool
30
31 // IsValidGo returns whether a reflect.Value is compatible with this type.
32 IsValidGo(reflect.Value) bool
33
34 // New returns a new field value.
35 // For scalars, it returns the default value of the field.
36 // For composite types, it returns a new mutable value.
37 New() protoreflect.Value
38
39 // Zero returns a new field value.
40 // For scalars, it returns the default value of the field.
41 // For composite types, it returns an immutable, empty value.
42 Zero() protoreflect.Value
43}
44
45// NewConverter matches a Go type with a protobuf field and returns a Converter
46// that converts between the two. Enums must be a named int32 kind that
47// implements protoreflect.Enum, and messages must be pointer to a named
48// struct type that implements protoreflect.ProtoMessage.
49//
50// This matcher deliberately supports a wider range of Go types than what
51// protoc-gen-go historically generated to be able to automatically wrap some
52// v1 messages generated by other forks of protoc-gen-go.
53func NewConverter(t reflect.Type, fd protoreflect.FieldDescriptor) Converter {
54 switch {
55 case fd.IsList():
56 return newListConverter(t, fd)
57 case fd.IsMap():
58 return newMapConverter(t, fd)
59 default:
60 return newSingularConverter(t, fd)
61 }
62}
63
64var (
65 boolType = reflect.TypeOf(bool(false))
66 int32Type = reflect.TypeOf(int32(0))
67 int64Type = reflect.TypeOf(int64(0))
68 uint32Type = reflect.TypeOf(uint32(0))
69 uint64Type = reflect.TypeOf(uint64(0))
70 float32Type = reflect.TypeOf(float32(0))
71 float64Type = reflect.TypeOf(float64(0))
72 stringType = reflect.TypeOf(string(""))
73 bytesType = reflect.TypeOf([]byte(nil))
74 byteType = reflect.TypeOf(byte(0))
75)
76
77var (
78 boolZero = protoreflect.ValueOfBool(false)
79 int32Zero = protoreflect.ValueOfInt32(0)
80 int64Zero = protoreflect.ValueOfInt64(0)
81 uint32Zero = protoreflect.ValueOfUint32(0)
82 uint64Zero = protoreflect.ValueOfUint64(0)
83 float32Zero = protoreflect.ValueOfFloat32(0)
84 float64Zero = protoreflect.ValueOfFloat64(0)
85 stringZero = protoreflect.ValueOfString("")
86 bytesZero = protoreflect.ValueOfBytes(nil)
87)
88
89func newSingularConverter(t reflect.Type, fd protoreflect.FieldDescriptor) Converter {
90 defVal := func(fd protoreflect.FieldDescriptor, zero protoreflect.Value) protoreflect.Value {
91 if fd.Cardinality() == protoreflect.Repeated {
92 // Default isn't defined for repeated fields.
93 return zero
94 }
95 return fd.Default()
96 }
97 switch fd.Kind() {
98 case protoreflect.BoolKind:
99 if t.Kind() == reflect.Bool {
100 return &boolConverter{t, defVal(fd, boolZero)}
101 }
102 case protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Sfixed32Kind:
103 if t.Kind() == reflect.Int32 {
104 return &int32Converter{t, defVal(fd, int32Zero)}
105 }
106 case protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Sfixed64Kind:
107 if t.Kind() == reflect.Int64 {
108 return &int64Converter{t, defVal(fd, int64Zero)}
109 }
110 case protoreflect.Uint32Kind, protoreflect.Fixed32Kind:
111 if t.Kind() == reflect.Uint32 {
112 return &uint32Converter{t, defVal(fd, uint32Zero)}
113 }
114 case protoreflect.Uint64Kind, protoreflect.Fixed64Kind:
115 if t.Kind() == reflect.Uint64 {
116 return &uint64Converter{t, defVal(fd, uint64Zero)}
117 }
118 case protoreflect.FloatKind:
119 if t.Kind() == reflect.Float32 {
120 return &float32Converter{t, defVal(fd, float32Zero)}
121 }
122 case protoreflect.DoubleKind:
123 if t.Kind() == reflect.Float64 {
124 return &float64Converter{t, defVal(fd, float64Zero)}
125 }
126 case protoreflect.StringKind:
127 if t.Kind() == reflect.String || (t.Kind() == reflect.Slice && t.Elem() == byteType) {
128 return &stringConverter{t, defVal(fd, stringZero)}
129 }
130 case protoreflect.BytesKind:
131 if t.Kind() == reflect.String || (t.Kind() == reflect.Slice && t.Elem() == byteType) {
132 return &bytesConverter{t, defVal(fd, bytesZero)}
133 }
134 case protoreflect.EnumKind:
135 // Handle enums, which must be a named int32 type.
136 if t.Kind() == reflect.Int32 {
137 return newEnumConverter(t, fd)
138 }
139 case protoreflect.MessageKind, protoreflect.GroupKind:
140 return newMessageConverter(t)
141 }
142 panic(fmt.Sprintf("invalid Go type %v for field %v", t, fd.FullName()))
143}
144
145type boolConverter struct {
146 goType reflect.Type
147 def protoreflect.Value
148}
149
150func (c *boolConverter) PBValueOf(v reflect.Value) protoreflect.Value {
151 if v.Type() != c.goType {
152 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
153 }
154 return protoreflect.ValueOfBool(v.Bool())
155}
156func (c *boolConverter) GoValueOf(v protoreflect.Value) reflect.Value {
157 return reflect.ValueOf(v.Bool()).Convert(c.goType)
158}
159func (c *boolConverter) IsValidPB(v protoreflect.Value) bool {
160 _, ok := v.Interface().(bool)
161 return ok
162}
163func (c *boolConverter) IsValidGo(v reflect.Value) bool {
164 return v.IsValid() && v.Type() == c.goType
165}
166func (c *boolConverter) New() protoreflect.Value { return c.def }
167func (c *boolConverter) Zero() protoreflect.Value { return c.def }
168
169type int32Converter struct {
170 goType reflect.Type
171 def protoreflect.Value
172}
173
174func (c *int32Converter) PBValueOf(v reflect.Value) protoreflect.Value {
175 if v.Type() != c.goType {
176 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
177 }
178 return protoreflect.ValueOfInt32(int32(v.Int()))
179}
180func (c *int32Converter) GoValueOf(v protoreflect.Value) reflect.Value {
181 return reflect.ValueOf(int32(v.Int())).Convert(c.goType)
182}
183func (c *int32Converter) IsValidPB(v protoreflect.Value) bool {
184 _, ok := v.Interface().(int32)
185 return ok
186}
187func (c *int32Converter) IsValidGo(v reflect.Value) bool {
188 return v.IsValid() && v.Type() == c.goType
189}
190func (c *int32Converter) New() protoreflect.Value { return c.def }
191func (c *int32Converter) Zero() protoreflect.Value { return c.def }
192
193type int64Converter struct {
194 goType reflect.Type
195 def protoreflect.Value
196}
197
198func (c *int64Converter) PBValueOf(v reflect.Value) protoreflect.Value {
199 if v.Type() != c.goType {
200 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
201 }
202 return protoreflect.ValueOfInt64(int64(v.Int()))
203}
204func (c *int64Converter) GoValueOf(v protoreflect.Value) reflect.Value {
205 return reflect.ValueOf(int64(v.Int())).Convert(c.goType)
206}
207func (c *int64Converter) IsValidPB(v protoreflect.Value) bool {
208 _, ok := v.Interface().(int64)
209 return ok
210}
211func (c *int64Converter) IsValidGo(v reflect.Value) bool {
212 return v.IsValid() && v.Type() == c.goType
213}
214func (c *int64Converter) New() protoreflect.Value { return c.def }
215func (c *int64Converter) Zero() protoreflect.Value { return c.def }
216
217type uint32Converter struct {
218 goType reflect.Type
219 def protoreflect.Value
220}
221
222func (c *uint32Converter) PBValueOf(v reflect.Value) protoreflect.Value {
223 if v.Type() != c.goType {
224 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
225 }
226 return protoreflect.ValueOfUint32(uint32(v.Uint()))
227}
228func (c *uint32Converter) GoValueOf(v protoreflect.Value) reflect.Value {
229 return reflect.ValueOf(uint32(v.Uint())).Convert(c.goType)
230}
231func (c *uint32Converter) IsValidPB(v protoreflect.Value) bool {
232 _, ok := v.Interface().(uint32)
233 return ok
234}
235func (c *uint32Converter) IsValidGo(v reflect.Value) bool {
236 return v.IsValid() && v.Type() == c.goType
237}
238func (c *uint32Converter) New() protoreflect.Value { return c.def }
239func (c *uint32Converter) Zero() protoreflect.Value { return c.def }
240
241type uint64Converter struct {
242 goType reflect.Type
243 def protoreflect.Value
244}
245
246func (c *uint64Converter) PBValueOf(v reflect.Value) protoreflect.Value {
247 if v.Type() != c.goType {
248 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
249 }
250 return protoreflect.ValueOfUint64(uint64(v.Uint()))
251}
252func (c *uint64Converter) GoValueOf(v protoreflect.Value) reflect.Value {
253 return reflect.ValueOf(uint64(v.Uint())).Convert(c.goType)
254}
255func (c *uint64Converter) IsValidPB(v protoreflect.Value) bool {
256 _, ok := v.Interface().(uint64)
257 return ok
258}
259func (c *uint64Converter) IsValidGo(v reflect.Value) bool {
260 return v.IsValid() && v.Type() == c.goType
261}
262func (c *uint64Converter) New() protoreflect.Value { return c.def }
263func (c *uint64Converter) Zero() protoreflect.Value { return c.def }
264
265type float32Converter struct {
266 goType reflect.Type
267 def protoreflect.Value
268}
269
270func (c *float32Converter) PBValueOf(v reflect.Value) protoreflect.Value {
271 if v.Type() != c.goType {
272 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
273 }
274 return protoreflect.ValueOfFloat32(float32(v.Float()))
275}
276func (c *float32Converter) GoValueOf(v protoreflect.Value) reflect.Value {
277 return reflect.ValueOf(float32(v.Float())).Convert(c.goType)
278}
279func (c *float32Converter) IsValidPB(v protoreflect.Value) bool {
280 _, ok := v.Interface().(float32)
281 return ok
282}
283func (c *float32Converter) IsValidGo(v reflect.Value) bool {
284 return v.IsValid() && v.Type() == c.goType
285}
286func (c *float32Converter) New() protoreflect.Value { return c.def }
287func (c *float32Converter) Zero() protoreflect.Value { return c.def }
288
289type float64Converter struct {
290 goType reflect.Type
291 def protoreflect.Value
292}
293
294func (c *float64Converter) PBValueOf(v reflect.Value) protoreflect.Value {
295 if v.Type() != c.goType {
296 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
297 }
298 return protoreflect.ValueOfFloat64(float64(v.Float()))
299}
300func (c *float64Converter) GoValueOf(v protoreflect.Value) reflect.Value {
301 return reflect.ValueOf(float64(v.Float())).Convert(c.goType)
302}
303func (c *float64Converter) IsValidPB(v protoreflect.Value) bool {
304 _, ok := v.Interface().(float64)
305 return ok
306}
307func (c *float64Converter) IsValidGo(v reflect.Value) bool {
308 return v.IsValid() && v.Type() == c.goType
309}
310func (c *float64Converter) New() protoreflect.Value { return c.def }
311func (c *float64Converter) Zero() protoreflect.Value { return c.def }
312
313type stringConverter struct {
314 goType reflect.Type
315 def protoreflect.Value
316}
317
318func (c *stringConverter) PBValueOf(v reflect.Value) protoreflect.Value {
319 if v.Type() != c.goType {
320 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
321 }
322 return protoreflect.ValueOfString(v.Convert(stringType).String())
323}
324func (c *stringConverter) GoValueOf(v protoreflect.Value) reflect.Value {
325 // protoreflect.Value.String never panics, so we go through an interface
326 // conversion here to check the type.
327 s := v.Interface().(string)
328 if c.goType.Kind() == reflect.Slice && s == "" {
329 return reflect.Zero(c.goType) // ensure empty string is []byte(nil)
330 }
331 return reflect.ValueOf(s).Convert(c.goType)
332}
333func (c *stringConverter) IsValidPB(v protoreflect.Value) bool {
334 _, ok := v.Interface().(string)
335 return ok
336}
337func (c *stringConverter) IsValidGo(v reflect.Value) bool {
338 return v.IsValid() && v.Type() == c.goType
339}
340func (c *stringConverter) New() protoreflect.Value { return c.def }
341func (c *stringConverter) Zero() protoreflect.Value { return c.def }
342
343type bytesConverter struct {
344 goType reflect.Type
345 def protoreflect.Value
346}
347
348func (c *bytesConverter) PBValueOf(v reflect.Value) protoreflect.Value {
349 if v.Type() != c.goType {
350 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
351 }
352 if c.goType.Kind() == reflect.String && v.Len() == 0 {
353 return protoreflect.ValueOfBytes(nil) // ensure empty string is []byte(nil)
354 }
355 return protoreflect.ValueOfBytes(v.Convert(bytesType).Bytes())
356}
357func (c *bytesConverter) GoValueOf(v protoreflect.Value) reflect.Value {
358 return reflect.ValueOf(v.Bytes()).Convert(c.goType)
359}
360func (c *bytesConverter) IsValidPB(v protoreflect.Value) bool {
361 _, ok := v.Interface().([]byte)
362 return ok
363}
364func (c *bytesConverter) IsValidGo(v reflect.Value) bool {
365 return v.IsValid() && v.Type() == c.goType
366}
367func (c *bytesConverter) New() protoreflect.Value { return c.def }
368func (c *bytesConverter) Zero() protoreflect.Value { return c.def }
369
370type enumConverter struct {
371 goType reflect.Type
372 def protoreflect.Value
373}
374
375func newEnumConverter(goType reflect.Type, fd protoreflect.FieldDescriptor) Converter {
376 var def protoreflect.Value
377 if fd.Cardinality() == protoreflect.Repeated {
378 def = protoreflect.ValueOfEnum(fd.Enum().Values().Get(0).Number())
379 } else {
380 def = fd.Default()
381 }
382 return &enumConverter{goType, def}
383}
384
385func (c *enumConverter) PBValueOf(v reflect.Value) protoreflect.Value {
386 if v.Type() != c.goType {
387 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
388 }
389 return protoreflect.ValueOfEnum(protoreflect.EnumNumber(v.Int()))
390}
391
392func (c *enumConverter) GoValueOf(v protoreflect.Value) reflect.Value {
393 return reflect.ValueOf(v.Enum()).Convert(c.goType)
394}
395
396func (c *enumConverter) IsValidPB(v protoreflect.Value) bool {
397 _, ok := v.Interface().(protoreflect.EnumNumber)
398 return ok
399}
400
401func (c *enumConverter) IsValidGo(v reflect.Value) bool {
402 return v.IsValid() && v.Type() == c.goType
403}
404
405func (c *enumConverter) New() protoreflect.Value {
406 return c.def
407}
408
409func (c *enumConverter) Zero() protoreflect.Value {
410 return c.def
411}
412
413type messageConverter struct {
414 goType reflect.Type
415}
416
417func newMessageConverter(goType reflect.Type) Converter {
418 return &messageConverter{goType}
419}
420
421func (c *messageConverter) PBValueOf(v reflect.Value) protoreflect.Value {
422 if v.Type() != c.goType {
423 panic(fmt.Sprintf("invalid type: got %v, want %v", v.Type(), c.goType))
424 }
425 if c.isNonPointer() {
426 if v.CanAddr() {
427 v = v.Addr() // T => *T
428 } else {
429 v = reflect.Zero(reflect.PtrTo(v.Type()))
430 }
431 }
432 if m, ok := v.Interface().(protoreflect.ProtoMessage); ok {
433 return protoreflect.ValueOfMessage(m.ProtoReflect())
434 }
435 return protoreflect.ValueOfMessage(legacyWrapMessage(v))
436}
437
438func (c *messageConverter) GoValueOf(v protoreflect.Value) reflect.Value {
439 m := v.Message()
440 var rv reflect.Value
441 if u, ok := m.(unwrapper); ok {
442 rv = reflect.ValueOf(u.protoUnwrap())
443 } else {
444 rv = reflect.ValueOf(m.Interface())
445 }
446 if c.isNonPointer() {
447 if rv.Type() != reflect.PtrTo(c.goType) {
448 panic(fmt.Sprintf("invalid type: got %v, want %v", rv.Type(), reflect.PtrTo(c.goType)))
449 }
450 if !rv.IsNil() {
451 rv = rv.Elem() // *T => T
452 } else {
453 rv = reflect.Zero(rv.Type().Elem())
454 }
455 }
456 if rv.Type() != c.goType {
457 panic(fmt.Sprintf("invalid type: got %v, want %v", rv.Type(), c.goType))
458 }
459 return rv
460}
461
462func (c *messageConverter) IsValidPB(v protoreflect.Value) bool {
463 m := v.Message()
464 var rv reflect.Value
465 if u, ok := m.(unwrapper); ok {
466 rv = reflect.ValueOf(u.protoUnwrap())
467 } else {
468 rv = reflect.ValueOf(m.Interface())
469 }
470 if c.isNonPointer() {
471 return rv.Type() == reflect.PtrTo(c.goType)
472 }
473 return rv.Type() == c.goType
474}
475
476func (c *messageConverter) IsValidGo(v reflect.Value) bool {
477 return v.IsValid() && v.Type() == c.goType
478}
479
480func (c *messageConverter) New() protoreflect.Value {
481 if c.isNonPointer() {
482 return c.PBValueOf(reflect.New(c.goType).Elem())
483 }
484 return c.PBValueOf(reflect.New(c.goType.Elem()))
485}
486
487func (c *messageConverter) Zero() protoreflect.Value {
488 return c.PBValueOf(reflect.Zero(c.goType))
489}
490
491// isNonPointer reports whether the type is a non-pointer type.
492// This never occurs for generated message types.
493func (c *messageConverter) isNonPointer() bool {
494 return c.goType.Kind() != reflect.Ptr
495}