59 lines
1.6 KiB
Go
59 lines
1.6 KiB
Go
// 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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// DiscardUnknown recursively discards all unknown fields from this message
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// and all embedded messages.
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//
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// When unmarshaling a message with unrecognized fields, the tags and values
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// of such fields are preserved in the Message. This allows a later call to
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// marshal to be able to produce a message that continues to have those
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// unrecognized fields. To avoid this, DiscardUnknown is used to
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// explicitly clear the unknown fields after unmarshaling.
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func DiscardUnknown(m Message) {
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if m != nil {
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discardUnknown(MessageReflect(m))
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}
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}
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func discardUnknown(m protoreflect.Message) {
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m.Range(func(fd protoreflect.FieldDescriptor, val 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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discardUnknown(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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discardUnknown(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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discardUnknown(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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// Discard unknown fields.
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if len(m.GetUnknown()) > 0 {
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m.SetUnknown(nil)
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}
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}
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