forked from toolshed/abra
34 lines
1.1 KiB
Go
34 lines
1.1 KiB
Go
// Copyright 2025 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 filedesc
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import "google.golang.org/protobuf/reflect/protoreflect"
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// UsePresenceForField reports whether the presence bitmap should be used for
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// the specified field.
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func UsePresenceForField(fd protoreflect.FieldDescriptor) (usePresence, canBeLazy bool) {
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switch {
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case fd.ContainingOneof() != nil && !fd.ContainingOneof().IsSynthetic():
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// Oneof fields never use the presence bitmap.
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//
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// Synthetic oneofs are an exception: Those are used to implement proto3
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// optional fields and hence should follow non-oneof field semantics.
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return false, false
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case fd.IsMap():
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// Map-typed fields never use the presence bitmap.
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return false, false
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case fd.Kind() == protoreflect.MessageKind || fd.Kind() == protoreflect.GroupKind:
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// Lazy fields always use the presence bitmap (only messages can be lazy).
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isLazy := fd.(interface{ IsLazy() bool }).IsLazy()
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return isLazy, isLazy
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default:
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// If the field has presence, use the presence bitmap.
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return fd.HasPresence(), false
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}
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}
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