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	"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.
42func 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}