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