consul/internal/protohcl/oneof.go

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package protohcl
import (
"fmt"
"strings"
"google.golang.org/protobuf/reflect/protoreflect"
)
type oneOfTracker struct {
namer FieldNamer
set map[protoreflect.FullName]string
}
func newOneOfTracker(namer FieldNamer) *oneOfTracker {
return &oneOfTracker{
namer: namer,
set: make(map[protoreflect.FullName]string),
}
}
func (o *oneOfTracker) markFieldAsSet(desc protoreflect.FieldDescriptor) error {
oneof := desc.ContainingOneof()
if oneof == nil {
return nil
}
oneOfName := oneof.FullName()
if otherFieldName, ok := o.set[oneOfName]; ok {
oneOfFields := oneof.Fields()
var builder strings.Builder
for i := 0; i < oneOfFields.Len(); i++ {
name := o.namer.NameField(oneOfFields.Get(i))
if i == oneOfFields.Len()-1 {
builder.WriteString(fmt.Sprintf("%q", name))
} else if i == oneOfFields.Len()-2 {
builder.WriteString(fmt.Sprintf("%q and ", name))
} else {
builder.WriteString(fmt.Sprintf("%q, ", name))
}
}
return fmt.Errorf("Cannot set %q because %q was previously set. Only one of %s may be set.", o.namer.NameField(desc), otherFieldName, builder.String())
}
o.set[oneOfName] = o.namer.NameField(desc)
return nil
}