1 // Copyright 2019 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4 5 package proto
6 7 import (
8 "reflect"
9 10 "google.golang.org/protobuf/reflect/protoreflect"
11 "google.golang.org/protobuf/runtime/protoiface"
12 )
13 14 // Equal reports whether two messages are equal,
15 // by recursively comparing the fields of the message.
16 //
17 // - Bytes fields are equal if they contain identical bytes.
18 // Empty bytes (regardless of nil-ness) are considered equal.
19 //
20 // - Floating-point fields are equal if they contain the same value.
21 // Unlike the == operator, a NaN is equal to another NaN.
22 //
23 // - Other scalar fields are equal if they contain the same value.
24 //
25 // - Message fields are equal if they have
26 // the same set of populated known and extension field values, and
27 // the same set of unknown fields values.
28 //
29 // - Lists are equal if they are the same length and
30 // each corresponding element is equal.
31 //
32 // - Maps are equal if they have the same set of keys and
33 // the corresponding value for each key is equal.
34 //
35 // An invalid message is not equal to a valid message.
36 // An invalid message is only equal to another invalid message of the
37 // same type. An invalid message often corresponds to a nil pointer
38 // of the concrete message type. For example, (*pb.M)(nil) is not equal
39 // to &pb.M{}.
40 // If two valid messages marshal to the same bytes under deterministic
41 // serialization, then Equal is guaranteed to report true.
42 func Equal(x, y Message) bool {
43 if x == nil || y == nil {
44 return x == nil && y == nil
45 }
46 if reflect.TypeOf(x).Kind() == reflect.Ptr && x == y {
47 // Avoid an expensive comparison if both inputs are identical pointers.
48 return true
49 }
50 mx := x.ProtoReflect()
51 my := y.ProtoReflect()
52 if mx.IsValid() != my.IsValid() {
53 return false
54 }
55 56 // Only one of the messages needs to implement the fast-path for it to work.
57 pmx := protoMethods(mx)
58 pmy := protoMethods(my)
59 if pmx != nil && pmy != nil && pmx.Equal != nil && pmy.Equal != nil {
60 return pmx.Equal(protoiface.EqualInput{MessageA: mx, MessageB: my}).Equal
61 }
62 63 vx := protoreflect.ValueOfMessage(mx)
64 vy := protoreflect.ValueOfMessage(my)
65 return vx.Equal(vy)
66 }
67