Damien Neil | c37adef | 2019-04-01 13:49:56 -0700 | [diff] [blame] | 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 | |
| 5 | package impl |
| 6 | |
| 7 | import ( |
| 8 | "fmt" |
| 9 | "reflect" |
| 10 | "sort" |
| 11 | |
| 12 | "google.golang.org/protobuf/internal/encoding/wire" |
| 13 | "google.golang.org/protobuf/internal/errors" |
| 14 | "google.golang.org/protobuf/proto" |
| 15 | pref "google.golang.org/protobuf/reflect/protoreflect" |
| 16 | ) |
| 17 | |
| 18 | var protoMessageType = reflect.TypeOf((*proto.Message)(nil)).Elem() |
| 19 | |
| 20 | func encoderFuncsForMap(fd pref.FieldDescriptor, ft reflect.Type) (funcs pointerCoderFuncs) { |
| 21 | // TODO: Consider generating specialized map coders. |
| 22 | keyField := fd.MapKey() |
| 23 | valField := fd.MapValue() |
| 24 | keyWiretag := wire.EncodeTag(1, wireTypes[keyField.Kind()]) |
| 25 | valWiretag := wire.EncodeTag(2, wireTypes[valField.Kind()]) |
| 26 | keyFuncs := encoderFuncsForValue(keyField, ft.Key()) |
| 27 | valFuncs := encoderFuncsForValue(valField, ft.Elem()) |
| 28 | |
| 29 | return pointerCoderFuncs{ |
| 30 | size: func(p pointer, tagsize int, opts marshalOptions) int { |
| 31 | return sizeMap(p, tagsize, ft, keyFuncs, valFuncs, opts) |
| 32 | }, |
| 33 | marshal: func(b []byte, p pointer, wiretag uint64, opts marshalOptions) ([]byte, error) { |
| 34 | return appendMap(b, p, wiretag, keyWiretag, valWiretag, ft, keyFuncs, valFuncs, opts) |
| 35 | }, |
| 36 | } |
| 37 | } |
| 38 | |
| 39 | const ( |
| 40 | mapKeyTagSize = 1 // field 1, tag size 1. |
| 41 | mapValTagSize = 1 // field 2, tag size 2. |
| 42 | ) |
| 43 | |
| 44 | func sizeMap(p pointer, tagsize int, goType reflect.Type, keyFuncs, valFuncs ifaceCoderFuncs, opts marshalOptions) int { |
| 45 | m := p.AsValueOf(goType).Elem() |
| 46 | n := 0 |
| 47 | if m.Len() == 0 { |
| 48 | return 0 |
| 49 | } |
| 50 | iter := mapRange(m) |
| 51 | for iter.Next() { |
| 52 | ki := iter.Key().Interface() |
| 53 | vi := iter.Value().Interface() |
| 54 | size := keyFuncs.size(ki, mapKeyTagSize, opts) + valFuncs.size(vi, mapValTagSize, opts) |
| 55 | n += wire.SizeBytes(size) + tagsize |
| 56 | } |
| 57 | return n |
| 58 | } |
| 59 | |
| 60 | func appendMap(b []byte, p pointer, wiretag, keyWiretag, valWiretag uint64, goType reflect.Type, keyFuncs, valFuncs ifaceCoderFuncs, opts marshalOptions) ([]byte, error) { |
| 61 | m := p.AsValueOf(goType).Elem() |
| 62 | var nerr errors.NonFatal |
| 63 | var err error |
| 64 | |
| 65 | if m.Len() == 0 { |
| 66 | return b, nil |
| 67 | } |
| 68 | |
| 69 | if opts.Deterministic() { |
| 70 | keys := m.MapKeys() |
| 71 | sort.Sort(mapKeys(keys)) |
| 72 | for _, k := range keys { |
| 73 | b, err = appendMapElement(b, k, m.MapIndex(k), wiretag, keyWiretag, valWiretag, keyFuncs, valFuncs, opts) |
| 74 | if !nerr.Merge(err) { |
| 75 | return b, err |
| 76 | } |
| 77 | } |
| 78 | return b, nerr.E |
| 79 | } |
| 80 | |
| 81 | iter := mapRange(m) |
| 82 | for iter.Next() { |
| 83 | b, err = appendMapElement(b, iter.Key(), iter.Value(), wiretag, keyWiretag, valWiretag, keyFuncs, valFuncs, opts) |
| 84 | if !nerr.Merge(err) { |
| 85 | return b, err |
| 86 | } |
| 87 | } |
| 88 | return b, nerr.E |
| 89 | } |
| 90 | |
| 91 | func appendMapElement(b []byte, key, value reflect.Value, wiretag, keyWiretag, valWiretag uint64, keyFuncs, valFuncs ifaceCoderFuncs, opts marshalOptions) ([]byte, error) { |
| 92 | ki := key.Interface() |
| 93 | vi := value.Interface() |
| 94 | b = wire.AppendVarint(b, wiretag) |
| 95 | size := keyFuncs.size(ki, mapKeyTagSize, opts) + valFuncs.size(vi, mapValTagSize, opts) |
| 96 | b = wire.AppendVarint(b, uint64(size)) |
| 97 | var nerr errors.NonFatal |
| 98 | b, err := keyFuncs.marshal(b, ki, keyWiretag, opts) |
| 99 | if !nerr.Merge(err) { |
| 100 | return b, err |
| 101 | } |
| 102 | b, err = valFuncs.marshal(b, vi, valWiretag, opts) |
| 103 | if !nerr.Merge(err) { |
| 104 | return b, err |
| 105 | } |
| 106 | return b, nerr.E |
| 107 | } |
| 108 | |
| 109 | // mapKeys returns a sort.Interface to be used for sorting the map keys. |
| 110 | // Map fields may have key types of non-float scalars, strings and enums. |
| 111 | func mapKeys(vs []reflect.Value) sort.Interface { |
| 112 | s := mapKeySorter{vs: vs} |
| 113 | |
| 114 | // Type specialization per https://developers.google.com/protocol-buffers/docs/proto#maps. |
| 115 | if len(vs) == 0 { |
| 116 | return s |
| 117 | } |
| 118 | switch vs[0].Kind() { |
| 119 | case reflect.Int32, reflect.Int64: |
| 120 | s.less = func(a, b reflect.Value) bool { return a.Int() < b.Int() } |
| 121 | case reflect.Uint32, reflect.Uint64: |
| 122 | s.less = func(a, b reflect.Value) bool { return a.Uint() < b.Uint() } |
| 123 | case reflect.Bool: |
| 124 | s.less = func(a, b reflect.Value) bool { return !a.Bool() && b.Bool() } // false < true |
| 125 | case reflect.String: |
| 126 | s.less = func(a, b reflect.Value) bool { return a.String() < b.String() } |
| 127 | default: |
| 128 | panic(fmt.Sprintf("unsupported map key type: %v", vs[0].Kind())) |
| 129 | } |
| 130 | |
| 131 | return s |
| 132 | } |
| 133 | |
| 134 | type mapKeySorter struct { |
| 135 | vs []reflect.Value |
| 136 | less func(a, b reflect.Value) bool |
| 137 | } |
| 138 | |
| 139 | func (s mapKeySorter) Len() int { return len(s.vs) } |
| 140 | func (s mapKeySorter) Swap(i, j int) { s.vs[i], s.vs[j] = s.vs[j], s.vs[i] } |
| 141 | func (s mapKeySorter) Less(i, j int) bool { |
| 142 | return s.less(s.vs[i], s.vs[j]) |
| 143 | } |