Scott Baker | 1fe7273 | 2019-10-21 10:58:51 -0700 | [diff] [blame] | 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 | |
| 34 | package proto |
| 35 | |
| 36 | import ( |
| 37 | "bytes" |
| 38 | "log" |
| 39 | "reflect" |
| 40 | "strings" |
| 41 | ) |
| 42 | |
| 43 | /* |
| 44 | Equal returns true iff protocol buffers a and b are equal. |
| 45 | The arguments must both be pointers to protocol buffer structs. |
| 46 | |
| 47 | Equality 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 | |
| 70 | The return value is undefined if a and b are not protocol buffers. |
| 71 | */ |
| 72 | func 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. |
| 96 | func 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. |
| 145 | func 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. |
| 232 | func 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 | |
| 238 | func 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 := extensionAsLegacyType(e1.value) |
| 250 | m2 := extensionAsLegacyType(e2.value) |
| 251 | |
| 252 | if m1 == nil && m2 == nil { |
| 253 | // Both have only encoded form. |
| 254 | if bytes.Equal(e1.enc, e2.enc) { |
| 255 | continue |
| 256 | } |
| 257 | // The bytes are different, but the extensions might still be |
| 258 | // equal. We need to decode them to compare. |
| 259 | } |
| 260 | |
| 261 | if m1 != nil && m2 != nil { |
| 262 | // Both are unencoded. |
| 263 | if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) { |
| 264 | return false |
| 265 | } |
| 266 | continue |
| 267 | } |
| 268 | |
| 269 | // At least one is encoded. To do a semantically correct comparison |
| 270 | // we need to unmarshal them first. |
| 271 | var desc *ExtensionDesc |
| 272 | if m := extensionMaps[base]; m != nil { |
| 273 | desc = m[extNum] |
| 274 | } |
| 275 | if desc == nil { |
| 276 | // If both have only encoded form and the bytes are the same, |
| 277 | // it is handled above. We get here when the bytes are different. |
| 278 | // We don't know how to decode it, so just compare them as byte |
| 279 | // slices. |
| 280 | log.Printf("proto: don't know how to compare extension %d of %v", extNum, base) |
| 281 | return false |
| 282 | } |
| 283 | var err error |
| 284 | if m1 == nil { |
| 285 | m1, err = decodeExtension(e1.enc, desc) |
| 286 | } |
| 287 | if m2 == nil && err == nil { |
| 288 | m2, err = decodeExtension(e2.enc, desc) |
| 289 | } |
| 290 | if err != nil { |
| 291 | // The encoded form is invalid. |
| 292 | log.Printf("proto: badly encoded extension %d of %v: %v", extNum, base, err) |
| 293 | return false |
| 294 | } |
| 295 | if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) { |
| 296 | return false |
| 297 | } |
| 298 | } |
| 299 | |
| 300 | return true |
| 301 | } |