// Go support for Protocol Buffers - Google's data interchange format
//
// Copyright 2011 The Go Authors. All rights reserved.
// https://github.com/golang/protobuf
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Protocol buffer comparison.
package proto
import (
"bytes"
"log"
"reflect"
"strings"
)
/*
Equal returns true iff protocol buffers a and b are equal.
The arguments must both be pointers to protocol buffer structs.
Equality is defined in this way:
- Two messages are equal iff they are the same type,
corresponding fields are equal, unknown field sets
are equal, and extensions sets are equal.
- Two set scalar fields are equal iff their values are equal.
If the fields are of a floating-point type, remember that
NaN != x for all x, including NaN. If the message is defined
in a proto3 .proto file, fields are not "set"; specifically,
zero length proto3 "bytes" fields are equal (nil == {}).
- Two repeated fields are equal iff their lengths are the same,
and their corresponding elements are equal. Note a "bytes" field,
although represented by []byte, is not a repeated field and the
rule for the scalar fields described above applies.
- Two unset fields are equal.
- Two unknown field sets are equal if their current
encoded state is equal.
- Two extension sets are equal iff they have corresponding
elements that are pairwise equal.
- Two map fields are equal iff their lengths are the same,
and they contain the same set of elements. Zero-length map
fields are equal.
- Every other combination of things are not equal.
The return value is undefined if a and b are not protocol buffers.
*/
func Equal(a, b Message) bool {
if a == nil || b == nil {
return a == b
}
v1, v2 := reflect.ValueOf(a), reflect.ValueOf(b)
if v1.Type() != v2.Type() {
return false
}
if v1.Kind() == reflect.Ptr {
if v1.IsNil() {
return v2.IsNil()
}
if v2.IsNil() {
return false
}
v1, v2 = v1.Elem(), v2.Elem()
}
if v1.Kind() != reflect.Struct {
return false
}
return equalStruct(v1, v2)
}
// v1 and v2 are known to have the same type.
func equalStruct(v1, v2 reflect.Value) bool {
sprop := GetProperties(v1.Type())
for i := 0; i < v1.NumField(); i++ {
f := v1.Type().Field(i)
if strings.HasPrefix(f.Name, "XXX_") {
continue
}
f1, f2 := v1.Field(i), v2.Field(i)
if f.Type.Kind() == reflect.Ptr {
if n1, n2 := f1.IsNil(), f2.IsNil(); n1 && n2 {
// both unset
continue
} else if n1 != n2 {
// set/unset mismatch
return false
}
f1, f2 = f1.Elem(), f2.Elem()
}
if !equalAny(f1, f2, sprop.Prop[i]) {
return false
}
}
if em1 := v1.FieldByName("XXX_InternalExtensions"); em1.IsValid() {
em2 := v2.FieldByName("XXX_InternalExtensions")
if !equalExtensions(v1.Type(), em1.Interface().(XXX_InternalExtensions), em2.Interface().(XXX_InternalExtensions)) {
return false
}
}
if em1 := v1.FieldByName("XXX_extensions"); em1.IsValid() {
em2 := v2.FieldByName("XXX_extensions")
if !equalExtMap(v1.Type(), em1.Interface().(map[int32]Extension), em2.Interface().(map[int32]Extension)) {
return false
}
}
uf := v1.FieldByName("XXX_unrecognized")
if !uf.IsValid() {
return true
}
u1 := uf.Bytes()
u2 := v2.FieldByName("XXX_unrecognized").Bytes()
return bytes.Equal(u1, u2)
}
// v1 and v2 are known to have the same type.
// prop may be nil.
func equalAny(v1, v2 reflect.Value, prop *Properties) bool {
if v1.Type() == protoMessageType {
m1, _ := v1.Interface().(Message)
m2, _ := v2.Interface().(Message)
return Equal(m1, m2)
}
switch v1.Kind() {
case reflect.Bool:
return v1.Bool() == v2.Bool()
case reflect.Float32, reflect.Float64:
return v1.Float() == v2.Float()
case reflect.Int32, reflect.Int64:
return v1.Int() == v2.Int()
case reflect.Interface:
// Probably a oneof field; compare the inner values.
n1, n2 := v1.IsNil(), v2.IsNil()
if n1 || n2 {
return n1 == n2
}
e1, e2 := v1.Elem(), v2.Elem()
if e1.Type() != e2.Type() {
return false
}
return equalAny(e1, e2, nil)
case reflect.Map:
if v1.Len() != v2.Len() {
return false
}
for _, key := range v1.MapKeys() {
val2 := v2.MapIndex(key)
if !val2.IsValid() {
// This key was not found in the second map.
return false
}
if !equalAny(v1.MapIndex(key), val2, nil) {
return false
}
}
return true
case reflect.Ptr:
// Maps may have nil values in them, so check for nil.
if v1.IsNil() && v2.IsNil() {
return true
}
if v1.IsNil() != v2.IsNil() {
return false
}
return equalAny(v1.Elem(), v2.Elem(), prop)
case reflect.Slice:
if v1.Type().Elem().Kind() == reflect.Uint8 {
// short circuit: []byte
// Edge case: if this is in a proto3 message, a zero length
// bytes field is considered the zero value.
if prop != nil && prop.proto3 && v1.Len() == 0 && v2.Len() == 0 {
return true
}
if v1.IsNil() != v2.IsNil() {
return false
}
return bytes.Equal(v1.Interface().([]byte), v2.Interface().([]byte))
}
if v1.Len() != v2.Len() {
return false
}
for i := 0; i < v1.Len(); i++ {
if !equalAny(v1.Index(i), v2.Index(i), prop) {
return false
}
}
return true
case reflect.String:
return v1.Interface().(string) == v2.Interface().(string)
case reflect.Struct:
return equalStruct(v1, v2)
case reflect.Uint32, reflect.Uint64:
return v1.Uint() == v2.Uint()
}
// unknown type, so not a protocol buffer
log.Printf("proto: don't know how to compare %v", v1)
return false
}
// base is the struct type that the extensions are based on.
// x1 and x2 are InternalExtensions.
func equalExtensions(base reflect.Type, x1, x2 XXX_InternalExtensions) bool {
em1, _ := x1.extensionsRead()
em2, _ := x2.extensionsRead()
return equalExtMap(base, em1, em2)
}
func equalExtMap(base reflect.Type, em1, em2 map[int32]Extension) bool {
if len(em1) != len(em2) {
return false
}
for extNum, e1 := range em1 {
e2, ok := em2[extNum]
if !ok {
return false
}
m1, m2 := e1.value, e2.value
if m1 == nil && m2 == nil {
// Both have only encoded form.
if bytes.Equal(e1.enc, e2.enc) {
continue
}
// The bytes are different, but the extensions might still be
// equal. We need to decode them to compare.
}
if m1 != nil && m2 != nil {
// Both are unencoded.
if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) {
return false
}
continue
}
// At least one is encoded. To do a semantically correct comparison
// we need to unmarshal them first.
var desc *ExtensionDesc
if m := extensionMaps[base]; m != nil {
desc = m[extNum]
}
if desc == nil {
// If both have only encoded form and the bytes are the same,
// it is handled above. We get here when the bytes are different.
// We don't know how to decode it, so just compare them as byte
// slices.
log.Printf("proto: don't know how to compare extension %d of %v", extNum, base)
return false
}
var err error
if m1 == nil {
m1, err = decodeExtension(e1.enc, desc)
}
if m2 == nil && err == nil {
m2, err = decodeExtension(e2.enc, desc)
}
if err != nil {
// The encoded form is invalid.
log.Printf("proto: badly encoded extension %d of %v: %v", extNum, base, err)
return false
}
if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) {
return false
}
}
return true
}
