podman

1
// Go support for Protocol Buffers - Google's data interchange format
2
//
3
// Copyright 2017 The Go Authors.  All rights reserved.
4
// https://github.com/golang/protobuf
5
//
6
// Redistribution and use in source and binary forms, with or without
7
// modification, are permitted provided that the following conditions are
8
// met:
9
//
10
//     * Redistributions of source code must retain the above copyright
11
// notice, this list of conditions and the following disclaimer.
12
//     * Redistributions in binary form must reproduce the above
13
// copyright notice, this list of conditions and the following disclaimer
14
// in the documentation and/or other materials provided with the
15
// distribution.
16
//     * Neither the name of Google Inc. nor the names of its
17
// contributors may be used to endorse or promote products derived from
18
// this software without specific prior written permission.
19
//
20
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31

32
package proto
33

34
import (
35
	"fmt"
36
	"reflect"
37
	"strings"
38
	"sync"
39
	"sync/atomic"
40
)
41

42
type generatedDiscarder interface {
43
	XXX_DiscardUnknown()
44
}
45

46
// DiscardUnknown recursively discards all unknown fields from this message
47
// and all embedded messages.
48
//
49
// When unmarshaling a message with unrecognized fields, the tags and values
50
// of such fields are preserved in the Message. This allows a later call to
51
// marshal to be able to produce a message that continues to have those
52
// unrecognized fields. To avoid this, DiscardUnknown is used to
53
// explicitly clear the unknown fields after unmarshaling.
54
//
55
// For proto2 messages, the unknown fields of message extensions are only
56
// discarded from messages that have been accessed via GetExtension.
57
func DiscardUnknown(m Message) {
58
	if m, ok := m.(generatedDiscarder); ok {
59
		m.XXX_DiscardUnknown()
60
		return
61
	}
62
	// TODO: Dynamically populate a InternalMessageInfo for legacy messages,
63
	// but the master branch has no implementation for InternalMessageInfo,
64
	// so it would be more work to replicate that approach.
65
	discardLegacy(m)
66
}
67

68
// DiscardUnknown recursively discards all unknown fields.
69
func (a *InternalMessageInfo) DiscardUnknown(m Message) {
70
	di := atomicLoadDiscardInfo(&a.discard)
71
	if di == nil {
72
		di = getDiscardInfo(reflect.TypeOf(m).Elem())
73
		atomicStoreDiscardInfo(&a.discard, di)
74
	}
75
	di.discard(toPointer(&m))
76
}
77

78
type discardInfo struct {
79
	typ reflect.Type
80

81
	initialized int32 // 0: only typ is valid, 1: everything is valid
82
	lock        sync.Mutex
83

84
	fields       []discardFieldInfo
85
	unrecognized field
86
}
87

88
type discardFieldInfo struct {
89
	field   field // Offset of field, guaranteed to be valid
90
	discard func(src pointer)
91
}
92

93
var (
94
	discardInfoMap  = map[reflect.Type]*discardInfo{}
95
	discardInfoLock sync.Mutex
96
)
97

98
func getDiscardInfo(t reflect.Type) *discardInfo {
99
	discardInfoLock.Lock()
100
	defer discardInfoLock.Unlock()
101
	di := discardInfoMap[t]
102
	if di == nil {
103
		di = &discardInfo{typ: t}
104
		discardInfoMap[t] = di
105
	}
106
	return di
107
}
108

109
func (di *discardInfo) discard(src pointer) {
110
	if src.isNil() {
111
		return // Nothing to do.
112
	}
113

114
	if atomic.LoadInt32(&di.initialized) == 0 {
115
		di.computeDiscardInfo()
116
	}
117

118
	for _, fi := range di.fields {
119
		sfp := src.offset(fi.field)
120
		fi.discard(sfp)
121
	}
122

123
	// For proto2 messages, only discard unknown fields in message extensions
124
	// that have been accessed via GetExtension.
125
	if em, err := extendable(src.asPointerTo(di.typ).Interface()); err == nil {
126
		// Ignore lock since DiscardUnknown is not concurrency safe.
127
		emm, _ := em.extensionsRead()
128
		for _, mx := range emm {
129
			if m, ok := mx.value.(Message); ok {
130
				DiscardUnknown(m)
131
			}
132
		}
133
	}
134

135
	if di.unrecognized.IsValid() {
136
		*src.offset(di.unrecognized).toBytes() = nil
137
	}
138
}
139

140
func (di *discardInfo) computeDiscardInfo() {
141
	di.lock.Lock()
142
	defer di.lock.Unlock()
143
	if di.initialized != 0 {
144
		return
145
	}
146
	t := di.typ
147
	n := t.NumField()
148

149
	for i := 0; i < n; i++ {
150
		f := t.Field(i)
151
		if strings.HasPrefix(f.Name, "XXX_") {
152
			continue
153
		}
154

155
		dfi := discardFieldInfo{field: toField(&f)}
156
		tf := f.Type
157

158
		// Unwrap tf to get its most basic type.
159
		var isPointer, isSlice bool
160
		if tf.Kind() == reflect.Slice && tf.Elem().Kind() != reflect.Uint8 {
161
			isSlice = true
162
			tf = tf.Elem()
163
		}
164
		if tf.Kind() == reflect.Ptr {
165
			isPointer = true
166
			tf = tf.Elem()
167
		}
168
		if isPointer && isSlice && tf.Kind() != reflect.Struct {
169
			panic(fmt.Sprintf("%v.%s cannot be a slice of pointers to primitive types", t, f.Name))
170
		}
171

172
		switch tf.Kind() {
173
		case reflect.Struct:
174
			switch {
175
			case !isPointer:
176
				panic(fmt.Sprintf("%v.%s cannot be a direct struct value", t, f.Name))
177
			case isSlice: // E.g., []*pb.T
178
				discardInfo := getDiscardInfo(tf)
179
				dfi.discard = func(src pointer) {
180
					sps := src.getPointerSlice()
181
					for _, sp := range sps {
182
						if !sp.isNil() {
183
							discardInfo.discard(sp)
184
						}
185
					}
186
				}
187
			default: // E.g., *pb.T
188
				discardInfo := getDiscardInfo(tf)
189
				dfi.discard = func(src pointer) {
190
					sp := src.getPointer()
191
					if !sp.isNil() {
192
						discardInfo.discard(sp)
193
					}
194
				}
195
			}
196
		case reflect.Map:
197
			switch {
198
			case isPointer || isSlice:
199
				panic(fmt.Sprintf("%v.%s cannot be a pointer to a map or a slice of map values", t, f.Name))
200
			default: // E.g., map[K]V
201
				if tf.Elem().Kind() == reflect.Ptr { // Proto struct (e.g., *T)
202
					dfi.discard = func(src pointer) {
203
						sm := src.asPointerTo(tf).Elem()
204
						if sm.Len() == 0 {
205
							return
206
						}
207
						for _, key := range sm.MapKeys() {
208
							val := sm.MapIndex(key)
209
							DiscardUnknown(val.Interface().(Message))
210
						}
211
					}
212
				} else {
213
					dfi.discard = func(pointer) {} // Noop
214
				}
215
			}
216
		case reflect.Interface:
217
			// Must be oneof field.
218
			switch {
219
			case isPointer || isSlice:
220
				panic(fmt.Sprintf("%v.%s cannot be a pointer to a interface or a slice of interface values", t, f.Name))
221
			default: // E.g., interface{}
222
				// TODO: Make this faster?
223
				dfi.discard = func(src pointer) {
224
					su := src.asPointerTo(tf).Elem()
225
					if !su.IsNil() {
226
						sv := su.Elem().Elem().Field(0)
227
						if sv.Kind() == reflect.Ptr && sv.IsNil() {
228
							return
229
						}
230
						switch sv.Type().Kind() {
231
						case reflect.Ptr: // Proto struct (e.g., *T)
232
							DiscardUnknown(sv.Interface().(Message))
233
						}
234
					}
235
				}
236
			}
237
		default:
238
			continue
239
		}
240
		di.fields = append(di.fields, dfi)
241
	}
242

243
	di.unrecognized = invalidField
244
	if f, ok := t.FieldByName("XXX_unrecognized"); ok {
245
		if f.Type != reflect.TypeOf([]byte{}) {
246
			panic("expected XXX_unrecognized to be of type []byte")
247
		}
248
		di.unrecognized = toField(&f)
249
	}
250

251
	atomic.StoreInt32(&di.initialized, 1)
252
}
253

254
func discardLegacy(m Message) {
255
	v := reflect.ValueOf(m)
256
	if v.Kind() != reflect.Ptr || v.IsNil() {
257
		return
258
	}
259
	v = v.Elem()
260
	if v.Kind() != reflect.Struct {
261
		return
262
	}
263
	t := v.Type()
264

265
	for i := 0; i < v.NumField(); i++ {
266
		f := t.Field(i)
267
		if strings.HasPrefix(f.Name, "XXX_") {
268
			continue
269
		}
270
		vf := v.Field(i)
271
		tf := f.Type
272

273
		// Unwrap tf to get its most basic type.
274
		var isPointer, isSlice bool
275
		if tf.Kind() == reflect.Slice && tf.Elem().Kind() != reflect.Uint8 {
276
			isSlice = true
277
			tf = tf.Elem()
278
		}
279
		if tf.Kind() == reflect.Ptr {
280
			isPointer = true
281
			tf = tf.Elem()
282
		}
283
		if isPointer && isSlice && tf.Kind() != reflect.Struct {
284
			panic(fmt.Sprintf("%T.%s cannot be a slice of pointers to primitive types", m, f.Name))
285
		}
286

287
		switch tf.Kind() {
288
		case reflect.Struct:
289
			switch {
290
			case !isPointer:
291
				panic(fmt.Sprintf("%T.%s cannot be a direct struct value", m, f.Name))
292
			case isSlice: // E.g., []*pb.T
293
				for j := 0; j < vf.Len(); j++ {
294
					discardLegacy(vf.Index(j).Interface().(Message))
295
				}
296
			default: // E.g., *pb.T
297
				discardLegacy(vf.Interface().(Message))
298
			}
299
		case reflect.Map:
300
			switch {
301
			case isPointer || isSlice:
302
				panic(fmt.Sprintf("%T.%s cannot be a pointer to a map or a slice of map values", m, f.Name))
303
			default: // E.g., map[K]V
304
				tv := vf.Type().Elem()
305
				if tv.Kind() == reflect.Ptr && tv.Implements(protoMessageType) { // Proto struct (e.g., *T)
306
					for _, key := range vf.MapKeys() {
307
						val := vf.MapIndex(key)
308
						discardLegacy(val.Interface().(Message))
309
					}
310
				}
311
			}
312
		case reflect.Interface:
313
			// Must be oneof field.
314
			switch {
315
			case isPointer || isSlice:
316
				panic(fmt.Sprintf("%T.%s cannot be a pointer to a interface or a slice of interface values", m, f.Name))
317
			default: // E.g., test_proto.isCommunique_Union interface
318
				if !vf.IsNil() && f.Tag.Get("protobuf_oneof") != "" {
319
					vf = vf.Elem() // E.g., *test_proto.Communique_Msg
320
					if !vf.IsNil() {
321
						vf = vf.Elem()   // E.g., test_proto.Communique_Msg
322
						vf = vf.Field(0) // E.g., Proto struct (e.g., *T) or primitive value
323
						if vf.Kind() == reflect.Ptr {
324
							discardLegacy(vf.Interface().(Message))
325
						}
326
					}
327
				}
328
			}
329
		}
330
	}
331

332
	if vf := v.FieldByName("XXX_unrecognized"); vf.IsValid() {
333
		if vf.Type() != reflect.TypeOf([]byte{}) {
334
			panic("expected XXX_unrecognized to be of type []byte")
335
		}
336
		vf.Set(reflect.ValueOf([]byte(nil)))
337
	}
338

339
	// For proto2 messages, only discard unknown fields in message extensions
340
	// that have been accessed via GetExtension.
341
	if em, err := extendable(m); err == nil {
342
		// Ignore lock since discardLegacy is not concurrency safe.
343
		emm, _ := em.extensionsRead()
344
		for _, mx := range emm {
345
			if m, ok := mx.value.(Message); ok {
346
				discardLegacy(m)
347
			}
348
		}
349
	}
350
}
351