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Girish Gowdra64503432020-01-07 10:59:10 +05301// Go support for Protocol Buffers - Google's data interchange format
2//
3// Copyright 2011 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// Protocol buffer comparison.
33
34package proto
35
36import (
37 "bytes"
38 "log"
39 "reflect"
40 "strings"
41)
42
43/*
44Equal returns true iff protocol buffers a and b are equal.
45The arguments must both be pointers to protocol buffer structs.
46
47Equality is defined in this way:
48 - Two messages are equal iff they are the same type,
49 corresponding fields are equal, unknown field sets
50 are equal, and extensions sets are equal.
51 - Two set scalar fields are equal iff their values are equal.
52 If the fields are of a floating-point type, remember that
53 NaN != x for all x, including NaN. If the message is defined
54 in a proto3 .proto file, fields are not "set"; specifically,
55 zero length proto3 "bytes" fields are equal (nil == {}).
56 - Two repeated fields are equal iff their lengths are the same,
57 and their corresponding elements are equal. Note a "bytes" field,
58 although represented by []byte, is not a repeated field and the
59 rule for the scalar fields described above applies.
60 - Two unset fields are equal.
61 - Two unknown field sets are equal if their current
62 encoded state is equal.
63 - Two extension sets are equal iff they have corresponding
64 elements that are pairwise equal.
65 - Two map fields are equal iff their lengths are the same,
66 and they contain the same set of elements. Zero-length map
67 fields are equal.
68 - Every other combination of things are not equal.
69
70The return value is undefined if a and b are not protocol buffers.
71*/
72func Equal(a, b Message) bool {
73 if a == nil || b == nil {
74 return a == b
75 }
76 v1, v2 := reflect.ValueOf(a), reflect.ValueOf(b)
77 if v1.Type() != v2.Type() {
78 return false
79 }
80 if v1.Kind() == reflect.Ptr {
81 if v1.IsNil() {
82 return v2.IsNil()
83 }
84 if v2.IsNil() {
85 return false
86 }
87 v1, v2 = v1.Elem(), v2.Elem()
88 }
89 if v1.Kind() != reflect.Struct {
90 return false
91 }
92 return equalStruct(v1, v2)
93}
94
95// v1 and v2 are known to have the same type.
96func equalStruct(v1, v2 reflect.Value) bool {
97 sprop := GetProperties(v1.Type())
98 for i := 0; i < v1.NumField(); i++ {
99 f := v1.Type().Field(i)
100 if strings.HasPrefix(f.Name, "XXX_") {
101 continue
102 }
103 f1, f2 := v1.Field(i), v2.Field(i)
104 if f.Type.Kind() == reflect.Ptr {
105 if n1, n2 := f1.IsNil(), f2.IsNil(); n1 && n2 {
106 // both unset
107 continue
108 } else if n1 != n2 {
109 // set/unset mismatch
110 return false
111 }
112 f1, f2 = f1.Elem(), f2.Elem()
113 }
114 if !equalAny(f1, f2, sprop.Prop[i]) {
115 return false
116 }
117 }
118
119 if em1 := v1.FieldByName("XXX_InternalExtensions"); em1.IsValid() {
120 em2 := v2.FieldByName("XXX_InternalExtensions")
121 if !equalExtensions(v1.Type(), em1.Interface().(XXX_InternalExtensions), em2.Interface().(XXX_InternalExtensions)) {
122 return false
123 }
124 }
125
126 if em1 := v1.FieldByName("XXX_extensions"); em1.IsValid() {
127 em2 := v2.FieldByName("XXX_extensions")
128 if !equalExtMap(v1.Type(), em1.Interface().(map[int32]Extension), em2.Interface().(map[int32]Extension)) {
129 return false
130 }
131 }
132
133 uf := v1.FieldByName("XXX_unrecognized")
134 if !uf.IsValid() {
135 return true
136 }
137
138 u1 := uf.Bytes()
139 u2 := v2.FieldByName("XXX_unrecognized").Bytes()
140 return bytes.Equal(u1, u2)
141}
142
143// v1 and v2 are known to have the same type.
144// prop may be nil.
145func equalAny(v1, v2 reflect.Value, prop *Properties) bool {
146 if v1.Type() == protoMessageType {
147 m1, _ := v1.Interface().(Message)
148 m2, _ := v2.Interface().(Message)
149 return Equal(m1, m2)
150 }
151 switch v1.Kind() {
152 case reflect.Bool:
153 return v1.Bool() == v2.Bool()
154 case reflect.Float32, reflect.Float64:
155 return v1.Float() == v2.Float()
156 case reflect.Int32, reflect.Int64:
157 return v1.Int() == v2.Int()
158 case reflect.Interface:
159 // Probably a oneof field; compare the inner values.
160 n1, n2 := v1.IsNil(), v2.IsNil()
161 if n1 || n2 {
162 return n1 == n2
163 }
164 e1, e2 := v1.Elem(), v2.Elem()
165 if e1.Type() != e2.Type() {
166 return false
167 }
168 return equalAny(e1, e2, nil)
169 case reflect.Map:
170 if v1.Len() != v2.Len() {
171 return false
172 }
173 for _, key := range v1.MapKeys() {
174 val2 := v2.MapIndex(key)
175 if !val2.IsValid() {
176 // This key was not found in the second map.
177 return false
178 }
179 if !equalAny(v1.MapIndex(key), val2, nil) {
180 return false
181 }
182 }
183 return true
184 case reflect.Ptr:
185 // Maps may have nil values in them, so check for nil.
186 if v1.IsNil() && v2.IsNil() {
187 return true
188 }
189 if v1.IsNil() != v2.IsNil() {
190 return false
191 }
192 return equalAny(v1.Elem(), v2.Elem(), prop)
193 case reflect.Slice:
194 if v1.Type().Elem().Kind() == reflect.Uint8 {
195 // short circuit: []byte
196
197 // Edge case: if this is in a proto3 message, a zero length
198 // bytes field is considered the zero value.
199 if prop != nil && prop.proto3 && v1.Len() == 0 && v2.Len() == 0 {
200 return true
201 }
202 if v1.IsNil() != v2.IsNil() {
203 return false
204 }
205 return bytes.Equal(v1.Interface().([]byte), v2.Interface().([]byte))
206 }
207
208 if v1.Len() != v2.Len() {
209 return false
210 }
211 for i := 0; i < v1.Len(); i++ {
212 if !equalAny(v1.Index(i), v2.Index(i), prop) {
213 return false
214 }
215 }
216 return true
217 case reflect.String:
218 return v1.Interface().(string) == v2.Interface().(string)
219 case reflect.Struct:
220 return equalStruct(v1, v2)
221 case reflect.Uint32, reflect.Uint64:
222 return v1.Uint() == v2.Uint()
223 }
224
225 // unknown type, so not a protocol buffer
226 log.Printf("proto: don't know how to compare %v", v1)
227 return false
228}
229
230// base is the struct type that the extensions are based on.
231// x1 and x2 are InternalExtensions.
232func equalExtensions(base reflect.Type, x1, x2 XXX_InternalExtensions) bool {
233 em1, _ := x1.extensionsRead()
234 em2, _ := x2.extensionsRead()
235 return equalExtMap(base, em1, em2)
236}
237
238func equalExtMap(base reflect.Type, em1, em2 map[int32]Extension) bool {
239 if len(em1) != len(em2) {
240 return false
241 }
242
243 for extNum, e1 := range em1 {
244 e2, ok := em2[extNum]
245 if !ok {
246 return false
247 }
248
249 m1, m2 := e1.value, e2.value
250
251 if m1 == nil && m2 == nil {
252 // Both have only encoded form.
253 if bytes.Equal(e1.enc, e2.enc) {
254 continue
255 }
256 // The bytes are different, but the extensions might still be
257 // equal. We need to decode them to compare.
258 }
259
260 if m1 != nil && m2 != nil {
261 // Both are unencoded.
262 if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) {
263 return false
264 }
265 continue
266 }
267
268 // At least one is encoded. To do a semantically correct comparison
269 // we need to unmarshal them first.
270 var desc *ExtensionDesc
271 if m := extensionMaps[base]; m != nil {
272 desc = m[extNum]
273 }
274 if desc == nil {
275 // If both have only encoded form and the bytes are the same,
276 // it is handled above. We get here when the bytes are different.
277 // We don't know how to decode it, so just compare them as byte
278 // slices.
279 log.Printf("proto: don't know how to compare extension %d of %v", extNum, base)
280 return false
281 }
282 var err error
283 if m1 == nil {
284 m1, err = decodeExtension(e1.enc, desc)
285 }
286 if m2 == nil && err == nil {
287 m2, err = decodeExtension(e2.enc, desc)
288 }
289 if err != nil {
290 // The encoded form is invalid.
291 log.Printf("proto: badly encoded extension %d of %v: %v", extNum, base, err)
292 return false
293 }
294 if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) {
295 return false
296 }
297 }
298
299 return true
300}