//FieldNamesToNumbers rewrites field names contained in the grammar to their respective field numbers found in the protocol buffer filedescriptorset.
//This allows for more speedy field comparisons in validation when used in conjunction with the ProtoNumParser.
func FieldNamesToNumbers(pkgName, msgName string, desc *descriptor.FileDescriptorSet, grammar *ast.Grammar) (*ast.Grammar, error) {
g := grammar.Clone()
descMap, err := proto.NewDescriptorMap(pkgName, msgName, desc)
if err != nil {
return nil, err
}
root := descMap.GetRoot()
refs := ast.NewRefLookup(g)
nameToNumber := &nameToNumber{
refs: make(map[string]*context),
descMap: descMap,
}
nameToNumber.refs["main"] = &context{root, false}
newRefs := make(map[string]*ast.Pattern)
oldContexts := 0
newContexts := 1
for oldContexts != newContexts {
oldContexts = newContexts
for name, context := range nameToNumber.refs {
newp, err := nameToNumber.translate(context, refs[name])
if err != nil {
return nil, err
}
newRefs[name] = newp
}
newContexts = len(nameToNumber.refs)
}
return ast.NewGrammar(newRefs), nil
}
//NewEncoder returns an Encoder that can marshal a parser.Interface into the specified protocol buffer message.
func NewEncoder(desc *descriptor.FileDescriptorSet, pkgName, msgName string) (Encoder, error) {
descMap, err := protoparser.NewDescriptorMap(pkgName, msgName, desc)
if err != nil {
return nil, err
}
return &encoder{msg: newMsg(descMap, descMap.GetRoot())}, nil
}