forked from TrueCloudLab/distribution
64 lines
1.6 KiB
Go
64 lines
1.6 KiB
Go
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// Copyright 2019 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 proto
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import (
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"google.golang.org/protobuf/reflect/protoreflect"
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)
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// SetDefaults sets unpopulated scalar fields to their default values.
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// Fields within a oneof are not set even if they have a default value.
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// SetDefaults is recursively called upon any populated message fields.
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func SetDefaults(m Message) {
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if m != nil {
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setDefaults(MessageReflect(m))
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}
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}
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func setDefaults(m protoreflect.Message) {
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fds := m.Descriptor().Fields()
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for i := 0; i < fds.Len(); i++ {
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fd := fds.Get(i)
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if !m.Has(fd) {
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if fd.HasDefault() && fd.ContainingOneof() == nil {
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v := fd.Default()
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if fd.Kind() == protoreflect.BytesKind {
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v = protoreflect.ValueOf(append([]byte(nil), v.Bytes()...)) // copy the default bytes
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}
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m.Set(fd, v)
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}
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continue
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}
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}
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m.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
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switch {
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// Handle singular message.
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case fd.Cardinality() != protoreflect.Repeated:
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if fd.Message() != nil {
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setDefaults(m.Get(fd).Message())
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}
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// Handle list of messages.
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case fd.IsList():
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if fd.Message() != nil {
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ls := m.Get(fd).List()
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for i := 0; i < ls.Len(); i++ {
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setDefaults(ls.Get(i).Message())
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}
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}
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// Handle map of messages.
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case fd.IsMap():
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if fd.MapValue().Message() != nil {
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ms := m.Get(fd).Map()
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ms.Range(func(_ protoreflect.MapKey, v protoreflect.Value) bool {
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setDefaults(v.Message())
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return true
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})
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}
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}
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return true
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})
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}
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