aboutsummaryrefslogtreecommitdiffstats
path: root/vendor/github.com/golang/protobuf/proto/equal.go
blob: d4db5a1c1457776f25424eedc9d9e64f4f4ab736 (plain) (blame)
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
// Go support for Protocol Buffers - Google's data interchange format
//
// Copyright 2011 The Go Authors.  All rights reserved.
// https://github.com/golang/protobuf
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// Protocol buffer comparison.

package proto

import (
	"bytes"
	"log"
	"reflect"
	"strings"
)

/*
Equal returns true iff protocol buffers a and b are equal.
The arguments must both be pointers to protocol buffer structs.

Equality is defined in this way:
  - Two messages are equal iff they are the same type,
    corresponding fields are equal, unknown field sets
    are equal, and extensions sets are equal.
  - Two set scalar fields are equal iff their values are equal.
    If the fields are of a floating-point type, remember that
    NaN != x for all x, including NaN. If the message is defined
    in a proto3 .proto file, fields are not "set"; specifically,
    zero length proto3 "bytes" fields are equal (nil == {}).
  - Two repeated fields are equal iff their lengths are the same,
    and their corresponding elements are equal. Note a "bytes" field,
    although represented by []byte, is not a repeated field and the
    rule for the scalar fields described above applies.
  - Two unset fields are equal.
  - Two unknown field sets are equal if their current
    encoded state is equal.
  - Two extension sets are equal iff they have corresponding
    elements that are pairwise equal.
  - Two map fields are equal iff their lengths are the same,
    and they contain the same set of elements. Zero-length map
    fields are equal.
  - Every other combination of things are not equal.

The return value is undefined if a and b are not protocol buffers.
*/
func Equal(a, b Message) bool {
	if a == nil || b == nil {
		return a == b
	}
	v1, v2 := reflect.ValueOf(a), reflect.ValueOf(b)
	if v1.Type() != v2.Type() {
		return false
	}
	if v1.Kind() == reflect.Ptr {
		if v1.IsNil() {
			return v2.IsNil()
		}
		if v2.IsNil() {
			return false
		}
		v1, v2 = v1.Elem(), v2.Elem()
	}
	if v1.Kind() != reflect.Struct {
		return false
	}
	return equalStruct(v1, v2)
}

// v1 and v2 are known to have the same type.
func equalStruct(v1, v2 reflect.Value) bool {
	sprop := GetProperties(v1.Type())
	for i := 0; i < v1.NumField(); i++ {
		f := v1.Type().Field(i)
		if strings.HasPrefix(f.Name, "XXX_") {
			continue
		}
		f1, f2 := v1.Field(i), v2.Field(i)
		if f.Type.Kind() == reflect.Ptr {
			if n1, n2 := f1.IsNil(), f2.IsNil(); n1 && n2 {
				// both unset
				continue
			} else if n1 != n2 {
				// set/unset mismatch
				return false
			}
			f1, f2 = f1.Elem(), f2.Elem()
		}
		if !equalAny(f1, f2, sprop.Prop[i]) {
			return false
		}
	}

	if em1 := v1.FieldByName("XXX_InternalExtensions"); em1.IsValid() {
		em2 := v2.FieldByName("XXX_InternalExtensions")
		if !equalExtensions(v1.Type(), em1.Interface().(XXX_InternalExtensions), em2.Interface().(XXX_InternalExtensions)) {
			return false
		}
	}

	if em1 := v1.FieldByName("XXX_extensions"); em1.IsValid() {
		em2 := v2.FieldByName("XXX_extensions")
		if !equalExtMap(v1.Type(), em1.Interface().(map[int32]Extension), em2.Interface().(map[int32]Extension)) {
			return false
		}
	}

	uf := v1.FieldByName("XXX_unrecognized")
	if !uf.IsValid() {
		return true
	}

	u1 := uf.Bytes()
	u2 := v2.FieldByName("XXX_unrecognized").Bytes()
	return bytes.Equal(u1, u2)
}

// v1 and v2 are known to have the same type.
// prop may be nil.
func equalAny(v1, v2 reflect.Value, prop *Properties) bool {
	if v1.Type() == protoMessageType {
		m1, _ := v1.Interface().(Message)
		m2, _ := v2.Interface().(Message)
		return Equal(m1, m2)
	}
	switch v1.Kind() {
	case reflect.Bool:
		return v1.Bool() == v2.Bool()
	case reflect.Float32, reflect.Float64:
		return v1.Float() == v2.Float()
	case reflect.Int32, reflect.Int64:
		return v1.Int() == v2.Int()
	case reflect.Interface:
		// Probably a oneof field; compare the inner values.
		n1, n2 := v1.IsNil(), v2.IsNil()
		if n1 || n2 {
			return n1 == n2
		}
		e1, e2 := v1.Elem(), v2.Elem()
		if e1.Type() != e2.Type() {
			return false
		}
		return equalAny(e1, e2, nil)
	case reflect.Map:
		if v1.Len() != v2.Len() {
			return false
		}
		for _, key := range v1.MapKeys() {
			val2 := v2.MapIndex(key)
			if !val2.IsValid() {
				// This key was not found in the second map.
				return false
			}
			if !equalAny(v1.MapIndex(key), val2, nil) {
				return false
			}
		}
		return true
	case reflect.Ptr:
		// Maps may have nil values in them, so check for nil.
		if v1.IsNil() && v2.IsNil() {
			return true
		}
		if v1.IsNil() != v2.IsNil() {
			return false
		}
		return equalAny(v1.Elem(), v2.Elem(), prop)
	case reflect.Slice:
		if v1.Type().Elem().Kind() == reflect.Uint8 {
			// short circuit: []byte

			// Edge case: if this is in a proto3 message, a zero length
			// bytes field is considered the zero value.
			if prop != nil && prop.proto3 && v1.Len() == 0 && v2.Len() == 0 {
				return true
			}
			if v1.IsNil() != v2.IsNil() {
				return false
			}
			return bytes.Equal(v1.Interface().([]byte), v2.Interface().([]byte))
		}

		if v1.Len() != v2.Len() {
			return false
		}
		for i := 0; i < v1.Len(); i++ {
			if !equalAny(v1.Index(i), v2.Index(i), prop) {
				return false
			}
		}
		return true
	case reflect.String:
		return v1.Interface().(string) == v2.Interface().(string)
	case reflect.Struct:
		return equalStruct(v1, v2)
	case reflect.Uint32, reflect.Uint64:
		return v1.Uint() == v2.Uint()
	}

	// unknown type, so not a protocol buffer
	log.Printf("proto: don't know how to compare %v", v1)
	return false
}

// base is the struct type that the extensions are based on.
// x1 and x2 are InternalExtensions.
func equalExtensions(base reflect.Type, x1, x2 XXX_InternalExtensions) bool {
	em1, _ := x1.extensionsRead()
	em2, _ := x2.extensionsRead()
	return equalExtMap(base, em1, em2)
}

func equalExtMap(base reflect.Type, em1, em2 map[int32]Extension) bool {
	if len(em1) != len(em2) {
		return false
	}

	for extNum, e1 := range em1 {
		e2, ok := em2[extNum]
		if !ok {
			return false
		}

		m1, m2 := e1.value, e2.value

		if m1 == nil && m2 == nil {
			// Both have only encoded form.
			if bytes.Equal(e1.enc, e2.enc) {
				continue
			}
			// The bytes are different, but the extensions might still be
			// equal. We need to decode them to compare.
		}

		if m1 != nil && m2 != nil {
			// Both are unencoded.
			if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) {
				return false
			}
			continue
		}

		// At least one is encoded. To do a semantically correct comparison
		// we need to unmarshal them first.
		var desc *ExtensionDesc
		if m := extensionMaps[base]; m != nil {
			desc = m[extNum]
		}
		if desc == nil {
			// If both have only encoded form and the bytes are the same,
			// it is handled above. We get here when the bytes are different.
			// We don't know how to decode it, so just compare them as byte
			// slices.
			log.Printf("proto: don't know how to compare extension %d of %v", extNum, base)
			return false
		}
		var err error
		if m1 == nil {
			m1, err = decodeExtension(e1.enc, desc)
		}
		if m2 == nil && err == nil {
			m2, err = decodeExtension(e2.enc, desc)
		}
		if err != nil {
			// The encoded form is invalid.
			log.Printf("proto: badly encoded extension %d of %v: %v", extNum, base, err)
			return false
		}
		if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) {
			return false
		}
	}

	return true
}