316 lines
9.4 KiB
Go
316 lines
9.4 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package descfmt provides functionality to format descriptors.
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package descfmt
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import (
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"fmt"
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"io"
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"reflect"
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"strconv"
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"strings"
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"google.golang.org/protobuf/internal/detrand"
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"google.golang.org/protobuf/internal/pragma"
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pref "google.golang.org/protobuf/reflect/protoreflect"
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)
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type list interface {
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Len() int
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pragma.DoNotImplement
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}
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func FormatList(s fmt.State, r rune, vs list) {
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io.WriteString(s, formatListOpt(vs, true, r == 'v' && (s.Flag('+') || s.Flag('#'))))
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}
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func formatListOpt(vs list, isRoot, allowMulti bool) string {
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start, end := "[", "]"
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if isRoot {
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var name string
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switch vs.(type) {
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case pref.Names:
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name = "Names"
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case pref.FieldNumbers:
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name = "FieldNumbers"
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case pref.FieldRanges:
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name = "FieldRanges"
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case pref.EnumRanges:
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name = "EnumRanges"
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case pref.FileImports:
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name = "FileImports"
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case pref.Descriptor:
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name = reflect.ValueOf(vs).MethodByName("Get").Type().Out(0).Name() + "s"
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}
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start, end = name+"{", "}"
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}
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var ss []string
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switch vs := vs.(type) {
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case pref.Names:
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for i := 0; i < vs.Len(); i++ {
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ss = append(ss, fmt.Sprint(vs.Get(i)))
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}
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return start + joinStrings(ss, false) + end
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case pref.FieldNumbers:
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for i := 0; i < vs.Len(); i++ {
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ss = append(ss, fmt.Sprint(vs.Get(i)))
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}
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return start + joinStrings(ss, false) + end
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case pref.FieldRanges:
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for i := 0; i < vs.Len(); i++ {
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r := vs.Get(i)
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if r[0]+1 == r[1] {
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ss = append(ss, fmt.Sprintf("%d", r[0]))
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} else {
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ss = append(ss, fmt.Sprintf("%d:%d", r[0], r[1])) // enum ranges are end exclusive
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}
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}
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return start + joinStrings(ss, false) + end
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case pref.EnumRanges:
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for i := 0; i < vs.Len(); i++ {
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r := vs.Get(i)
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if r[0] == r[1] {
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ss = append(ss, fmt.Sprintf("%d", r[0]))
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} else {
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ss = append(ss, fmt.Sprintf("%d:%d", r[0], int64(r[1])+1)) // enum ranges are end inclusive
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}
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}
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return start + joinStrings(ss, false) + end
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case pref.FileImports:
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for i := 0; i < vs.Len(); i++ {
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var rs records
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rs.Append(reflect.ValueOf(vs.Get(i)), "Path", "Package", "IsPublic", "IsWeak")
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ss = append(ss, "{"+rs.Join()+"}")
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}
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return start + joinStrings(ss, allowMulti) + end
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default:
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_, isEnumValue := vs.(pref.EnumValueDescriptors)
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for i := 0; i < vs.Len(); i++ {
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m := reflect.ValueOf(vs).MethodByName("Get")
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v := m.Call([]reflect.Value{reflect.ValueOf(i)})[0].Interface()
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ss = append(ss, formatDescOpt(v.(pref.Descriptor), false, allowMulti && !isEnumValue))
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}
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return start + joinStrings(ss, allowMulti && isEnumValue) + end
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}
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}
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// descriptorAccessors is a list of accessors to print for each descriptor.
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//
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// Do not print all accessors since some contain redundant information,
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// while others are pointers that we do not want to follow since the descriptor
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// is actually a cyclic graph.
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//
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// Using a list allows us to print the accessors in a sensible order.
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var descriptorAccessors = map[reflect.Type][]string{
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reflect.TypeOf((*pref.FileDescriptor)(nil)).Elem(): {"Path", "Package", "Imports", "Messages", "Enums", "Extensions", "Services"},
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reflect.TypeOf((*pref.MessageDescriptor)(nil)).Elem(): {"IsMapEntry", "Fields", "Oneofs", "ReservedNames", "ReservedRanges", "RequiredNumbers", "ExtensionRanges", "Messages", "Enums", "Extensions"},
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reflect.TypeOf((*pref.FieldDescriptor)(nil)).Elem(): {"Number", "Cardinality", "Kind", "HasJSONName", "JSONName", "HasPresence", "IsExtension", "IsPacked", "IsWeak", "IsList", "IsMap", "MapKey", "MapValue", "HasDefault", "Default", "ContainingOneof", "ContainingMessage", "Message", "Enum"},
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reflect.TypeOf((*pref.OneofDescriptor)(nil)).Elem(): {"Fields"}, // not directly used; must keep in sync with formatDescOpt
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reflect.TypeOf((*pref.EnumDescriptor)(nil)).Elem(): {"Values", "ReservedNames", "ReservedRanges"},
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reflect.TypeOf((*pref.EnumValueDescriptor)(nil)).Elem(): {"Number"},
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reflect.TypeOf((*pref.ServiceDescriptor)(nil)).Elem(): {"Methods"},
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reflect.TypeOf((*pref.MethodDescriptor)(nil)).Elem(): {"Input", "Output", "IsStreamingClient", "IsStreamingServer"},
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}
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func FormatDesc(s fmt.State, r rune, t pref.Descriptor) {
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io.WriteString(s, formatDescOpt(t, true, r == 'v' && (s.Flag('+') || s.Flag('#'))))
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}
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func formatDescOpt(t pref.Descriptor, isRoot, allowMulti bool) string {
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rv := reflect.ValueOf(t)
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rt := rv.MethodByName("ProtoType").Type().In(0)
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start, end := "{", "}"
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if isRoot {
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start = rt.Name() + "{"
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}
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_, isFile := t.(pref.FileDescriptor)
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rs := records{allowMulti: allowMulti}
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if t.IsPlaceholder() {
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if isFile {
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rs.Append(rv, "Path", "Package", "IsPlaceholder")
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} else {
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rs.Append(rv, "FullName", "IsPlaceholder")
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}
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} else {
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switch {
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case isFile:
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rs.Append(rv, "Syntax")
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case isRoot:
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rs.Append(rv, "Syntax", "FullName")
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default:
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rs.Append(rv, "Name")
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}
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switch t := t.(type) {
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case pref.FieldDescriptor:
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for _, s := range descriptorAccessors[rt] {
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switch s {
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case "MapKey":
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if k := t.MapKey(); k != nil {
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rs.recs = append(rs.recs, [2]string{"MapKey", k.Kind().String()})
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}
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case "MapValue":
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if v := t.MapValue(); v != nil {
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switch v.Kind() {
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case pref.EnumKind:
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rs.recs = append(rs.recs, [2]string{"MapValue", string(v.Enum().FullName())})
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case pref.MessageKind, pref.GroupKind:
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rs.recs = append(rs.recs, [2]string{"MapValue", string(v.Message().FullName())})
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default:
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rs.recs = append(rs.recs, [2]string{"MapValue", v.Kind().String()})
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}
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}
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case "ContainingOneof":
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if od := t.ContainingOneof(); od != nil {
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rs.recs = append(rs.recs, [2]string{"Oneof", string(od.Name())})
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}
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case "ContainingMessage":
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if t.IsExtension() {
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rs.recs = append(rs.recs, [2]string{"Extendee", string(t.ContainingMessage().FullName())})
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}
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case "Message":
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if !t.IsMap() {
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rs.Append(rv, s)
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}
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default:
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rs.Append(rv, s)
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}
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}
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case pref.OneofDescriptor:
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var ss []string
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fs := t.Fields()
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for i := 0; i < fs.Len(); i++ {
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ss = append(ss, string(fs.Get(i).Name()))
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}
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if len(ss) > 0 {
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rs.recs = append(rs.recs, [2]string{"Fields", "[" + joinStrings(ss, false) + "]"})
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}
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default:
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rs.Append(rv, descriptorAccessors[rt]...)
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}
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if rv.MethodByName("GoType").IsValid() {
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rs.Append(rv, "GoType")
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}
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}
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return start + rs.Join() + end
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}
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type records struct {
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recs [][2]string
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allowMulti bool
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}
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func (rs *records) Append(v reflect.Value, accessors ...string) {
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for _, a := range accessors {
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var rv reflect.Value
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if m := v.MethodByName(a); m.IsValid() {
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rv = m.Call(nil)[0]
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}
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if v.Kind() == reflect.Struct && !rv.IsValid() {
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rv = v.FieldByName(a)
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}
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if !rv.IsValid() {
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panic(fmt.Sprintf("unknown accessor: %v.%s", v.Type(), a))
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}
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if _, ok := rv.Interface().(pref.Value); ok {
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rv = rv.MethodByName("Interface").Call(nil)[0]
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if !rv.IsNil() {
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rv = rv.Elem()
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}
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}
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// Ignore zero values.
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var isZero bool
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switch rv.Kind() {
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case reflect.Interface, reflect.Slice:
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isZero = rv.IsNil()
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case reflect.Bool:
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isZero = rv.Bool() == false
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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isZero = rv.Int() == 0
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
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isZero = rv.Uint() == 0
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case reflect.String:
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isZero = rv.String() == ""
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}
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if n, ok := rv.Interface().(list); ok {
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isZero = n.Len() == 0
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}
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if isZero {
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continue
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}
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// Format the value.
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var s string
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v := rv.Interface()
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switch v := v.(type) {
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case list:
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s = formatListOpt(v, false, rs.allowMulti)
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case pref.FieldDescriptor, pref.OneofDescriptor, pref.EnumValueDescriptor, pref.MethodDescriptor:
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s = string(v.(pref.Descriptor).Name())
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case pref.Descriptor:
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s = string(v.FullName())
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case string:
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s = strconv.Quote(v)
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case []byte:
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s = fmt.Sprintf("%q", v)
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default:
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s = fmt.Sprint(v)
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}
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rs.recs = append(rs.recs, [2]string{a, s})
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}
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}
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func (rs *records) Join() string {
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var ss []string
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// In single line mode, simply join all records with commas.
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if !rs.allowMulti {
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for _, r := range rs.recs {
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ss = append(ss, r[0]+formatColon(0)+r[1])
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}
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return joinStrings(ss, false)
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}
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// In allowMulti line mode, align single line records for more readable output.
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var maxLen int
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flush := func(i int) {
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for _, r := range rs.recs[len(ss):i] {
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ss = append(ss, r[0]+formatColon(maxLen-len(r[0]))+r[1])
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}
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maxLen = 0
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}
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for i, r := range rs.recs {
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if isMulti := strings.Contains(r[1], "\n"); isMulti {
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flush(i)
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ss = append(ss, r[0]+formatColon(0)+strings.Join(strings.Split(r[1], "\n"), "\n\t"))
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} else if maxLen < len(r[0]) {
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maxLen = len(r[0])
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}
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}
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flush(len(rs.recs))
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return joinStrings(ss, true)
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}
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func formatColon(padding int) string {
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// Deliberately introduce instability into the debug output to
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// discourage users from performing string comparisons.
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// This provides us flexibility to change the output in the future.
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if detrand.Bool() {
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return ":" + strings.Repeat(" ", 1+padding) // use non-breaking spaces (U+00a0)
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} else {
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return ":" + strings.Repeat(" ", 1+padding) // use regular spaces (U+0020)
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}
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}
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func joinStrings(ss []string, isMulti bool) string {
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if len(ss) == 0 {
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return ""
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}
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if isMulti {
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return "\n\t" + strings.Join(ss, "\n\t") + "\n"
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}
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return strings.Join(ss, ", ")
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}
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