xref: /aosp_15_r20/external/golang-protobuf/proto/equal.go (revision 1c12ee1efe575feb122dbf939ff15148a3b3e8f2)
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
5package proto
6
7import (
8	"reflect"
9
10	"google.golang.org/protobuf/reflect/protoreflect"
11)
12
13// Equal reports whether two messages are equal,
14// by recursively comparing the fields of the message.
15//
16//   - Bytes fields are equal if they contain identical bytes.
17//     Empty bytes (regardless of nil-ness) are considered equal.
18//
19//   - Floating-point fields are equal if they contain the same value.
20//     Unlike the == operator, a NaN is equal to another NaN.
21//
22//   - Other scalar fields are equal if they contain the same value.
23//
24//   - Message fields are equal if they have
25//     the same set of populated known and extension field values, and
26//     the same set of unknown fields values.
27//
28//   - Lists are equal if they are the same length and
29//     each corresponding element is equal.
30//
31//   - Maps are equal if they have the same set of keys and
32//     the corresponding value for each key is equal.
33//
34// An invalid message is not equal to a valid message.
35// An invalid message is only equal to another invalid message of the
36// same type. An invalid message often corresponds to a nil pointer
37// of the concrete message type. For example, (*pb.M)(nil) is not equal
38// to &pb.M{}.
39// If two valid messages marshal to the same bytes under deterministic
40// serialization, then Equal is guaranteed to report true.
41func Equal(x, y Message) bool {
42	if x == nil || y == nil {
43		return x == nil && y == nil
44	}
45	if reflect.TypeOf(x).Kind() == reflect.Ptr && x == y {
46		// Avoid an expensive comparison if both inputs are identical pointers.
47		return true
48	}
49	mx := x.ProtoReflect()
50	my := y.ProtoReflect()
51	if mx.IsValid() != my.IsValid() {
52		return false
53	}
54	vx := protoreflect.ValueOfMessage(mx)
55	vy := protoreflect.ValueOfMessage(my)
56	return vx.Equal(vy)
57}
58