1// 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 (a "bytes" field, 58 although represented by []byte, is not a repeated field) 59 - Two unset fields are equal. 60 - Two unknown field sets are equal if their current 61 encoded state is equal. 62 - Two extension sets are equal iff they have corresponding 63 elements that are pairwise equal. 64 - Every other combination of things are not equal. 65 66The return value is undefined if a and b are not protocol buffers. 67*/ 68func Equal(a, b Message) bool { 69 if a == nil || b == nil { 70 return a == b 71 } 72 v1, v2 := reflect.ValueOf(a), reflect.ValueOf(b) 73 if v1.Type() != v2.Type() { 74 return false 75 } 76 if v1.Kind() == reflect.Ptr { 77 if v1.IsNil() { 78 return v2.IsNil() 79 } 80 if v2.IsNil() { 81 return false 82 } 83 v1, v2 = v1.Elem(), v2.Elem() 84 } 85 if v1.Kind() != reflect.Struct { 86 return false 87 } 88 return equalStruct(v1, v2) 89} 90 91// v1 and v2 are known to have the same type. 92func equalStruct(v1, v2 reflect.Value) bool { 93 sprop := GetProperties(v1.Type()) 94 for i := 0; i < v1.NumField(); i++ { 95 f := v1.Type().Field(i) 96 if strings.HasPrefix(f.Name, "XXX_") { 97 continue 98 } 99 f1, f2 := v1.Field(i), v2.Field(i) 100 if f.Type.Kind() == reflect.Ptr { 101 if n1, n2 := f1.IsNil(), f2.IsNil(); n1 && n2 { 102 // both unset 103 continue 104 } else if n1 != n2 { 105 // set/unset mismatch 106 return false 107 } 108 b1, ok := f1.Interface().(raw) 109 if ok { 110 b2 := f2.Interface().(raw) 111 // RawMessage 112 if !bytes.Equal(b1.Bytes(), b2.Bytes()) { 113 return false 114 } 115 continue 116 } 117 f1, f2 = f1.Elem(), f2.Elem() 118 } 119 if !equalAny(f1, f2, sprop.Prop[i]) { 120 return false 121 } 122 } 123 124 if em1 := v1.FieldByName("XXX_extensions"); em1.IsValid() { 125 em2 := v2.FieldByName("XXX_extensions") 126 if !equalExtensions(v1.Type(), em1.Interface().(map[int32]Extension), em2.Interface().(map[int32]Extension)) { 127 return false 128 } 129 } 130 131 uf := v1.FieldByName("XXX_unrecognized") 132 if !uf.IsValid() { 133 return true 134 } 135 136 u1 := uf.Bytes() 137 u2 := v2.FieldByName("XXX_unrecognized").Bytes() 138 if !bytes.Equal(u1, u2) { 139 return false 140 } 141 142 return true 143} 144 145// v1 and v2 are known to have the same type. 146// prop may be nil. 147func equalAny(v1, v2 reflect.Value, prop *Properties) bool { 148 if v1.Type() == protoMessageType { 149 m1, _ := v1.Interface().(Message) 150 m2, _ := v2.Interface().(Message) 151 return Equal(m1, m2) 152 } 153 switch v1.Kind() { 154 case reflect.Bool: 155 return v1.Bool() == v2.Bool() 156 case reflect.Float32, reflect.Float64: 157 return v1.Float() == v2.Float() 158 case reflect.Int32, reflect.Int64: 159 return v1.Int() == v2.Int() 160 case reflect.Interface: 161 // Probably a oneof field; compare the inner values. 162 n1, n2 := v1.IsNil(), v2.IsNil() 163 if n1 || n2 { 164 return n1 == n2 165 } 166 e1, e2 := v1.Elem(), v2.Elem() 167 if e1.Type() != e2.Type() { 168 return false 169 } 170 return equalAny(e1, e2, nil) 171 case reflect.Map: 172 if v1.Len() != v2.Len() { 173 return false 174 } 175 for _, key := range v1.MapKeys() { 176 val2 := v2.MapIndex(key) 177 if !val2.IsValid() { 178 // This key was not found in the second map. 179 return false 180 } 181 if !equalAny(v1.MapIndex(key), val2, nil) { 182 return false 183 } 184 } 185 return true 186 case reflect.Ptr: 187 return equalAny(v1.Elem(), v2.Elem(), prop) 188 case reflect.Slice: 189 if v1.Type().Elem().Kind() == reflect.Uint8 { 190 // short circuit: []byte 191 192 // Edge case: if this is in a proto3 message, a zero length 193 // bytes field is considered the zero value. 194 if prop != nil && prop.proto3 && v1.Len() == 0 && v2.Len() == 0 { 195 return true 196 } 197 if v1.IsNil() != v2.IsNil() { 198 return false 199 } 200 return bytes.Equal(v1.Interface().([]byte), v2.Interface().([]byte)) 201 } 202 203 if v1.Len() != v2.Len() { 204 return false 205 } 206 for i := 0; i < v1.Len(); i++ { 207 if !equalAny(v1.Index(i), v2.Index(i), prop) { 208 return false 209 } 210 } 211 return true 212 case reflect.String: 213 return v1.Interface().(string) == v2.Interface().(string) 214 case reflect.Struct: 215 return equalStruct(v1, v2) 216 case reflect.Uint32, reflect.Uint64: 217 return v1.Uint() == v2.Uint() 218 } 219 220 // unknown type, so not a protocol buffer 221 log.Printf("proto: don't know how to compare %v", v1) 222 return false 223} 224 225// base is the struct type that the extensions are based on. 226// em1 and em2 are extension maps. 227func equalExtensions(base reflect.Type, em1, em2 map[int32]Extension) bool { 228 if len(em1) != len(em2) { 229 return false 230 } 231 232 for extNum, e1 := range em1 { 233 e2, ok := em2[extNum] 234 if !ok { 235 return false 236 } 237 238 m1, m2 := e1.value, e2.value 239 240 if m1 != nil && m2 != nil { 241 // Both are unencoded. 242 if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) { 243 return false 244 } 245 continue 246 } 247 248 // At least one is encoded. To do a semantically correct comparison 249 // we need to unmarshal them first. 250 var desc *ExtensionDesc 251 if m := extensionMaps[base]; m != nil { 252 desc = m[extNum] 253 } 254 if desc == nil { 255 log.Printf("proto: don't know how to compare extension %d of %v", extNum, base) 256 continue 257 } 258 var err error 259 if m1 == nil { 260 m1, err = decodeExtension(e1.enc, desc) 261 } 262 if m2 == nil && err == nil { 263 m2, err = decodeExtension(e2.enc, desc) 264 } 265 if err != nil { 266 // The encoded form is invalid. 267 log.Printf("proto: badly encoded extension %d of %v: %v", extNum, base, err) 268 return false 269 } 270 if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) { 271 return false 272 } 273 } 274 275 return true 276} 277