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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package impl
import (
"reflect"
"strconv"
"strings"
pref "google.golang.org/proto/reflect/protoreflect"
)
type MessageInfo struct {
// TODO: Split fields into dense and sparse maps similar to the current
// table-driven implementation in v1?
fields map[pref.FieldNumber]*fieldInfo
}
// generateFieldFuncs generates per-field functions for all common operations
// to be performed on each field. It takes in a reflect.Type representing the
// Go struct, and a protoreflect.MessageDescriptor to match with the fields
// in the struct.
//
// This code assumes that the struct is well-formed and panics if there are
// any discrepancies.
func (mi *MessageInfo) generateFieldFuncs(t reflect.Type, md pref.MessageDescriptor) {
// Generate a mapping of field numbers and names to Go struct field or type.
fields := map[pref.FieldNumber]reflect.StructField{}
oneofs := map[pref.Name]reflect.StructField{}
oneofFields := map[pref.FieldNumber]reflect.Type{}
special := map[string]reflect.StructField{}
fieldLoop:
for i := 0; i < t.NumField(); i++ {
f := t.Field(i)
for _, s := range strings.Split(f.Tag.Get("protobuf"), ",") {
if len(s) > 0 && strings.Trim(s, "0123456789") == "" {
n, _ := strconv.ParseUint(s, 10, 64)
fields[pref.FieldNumber(n)] = f
continue fieldLoop
}
}
if s := f.Tag.Get("protobuf_oneof"); len(s) > 0 {
oneofs[pref.Name(s)] = f
continue fieldLoop
}
switch f.Name {
case "XXX_weak", "XXX_unrecognized", "XXX_sizecache", "XXX_extensions", "XXX_InternalExtensions":
special[f.Name] = f
continue fieldLoop
}
}
if fn, ok := t.MethodByName("XXX_OneofFuncs"); ok {
vs := fn.Func.Call([]reflect.Value{reflect.New(fn.Type.In(0)).Elem()})[3]
oneofLoop:
for _, v := range vs.Interface().([]interface{}) {
tf := reflect.TypeOf(v).Elem()
f := tf.Field(0)
for _, s := range strings.Split(f.Tag.Get("protobuf"), ",") {
if len(s) > 0 && strings.Trim(s, "0123456789") == "" {
n, _ := strconv.ParseUint(s, 10, 64)
oneofFields[pref.FieldNumber(n)] = tf
continue oneofLoop
}
}
}
}
mi.fields = map[pref.FieldNumber]*fieldInfo{}
for i := 0; i < md.Fields().Len(); i++ {
fd := md.Fields().Get(i)
fs := fields[fd.Number()]
var fi fieldInfo
switch {
case fd.IsWeak():
fi = fieldInfoForWeak(fd, special["XXX_weak"])
case fd.OneofType() != nil:
fi = fieldInfoForOneof(fd, oneofs[fd.OneofType().Name()], oneofFields[fd.Number()])
case fd.IsMap():
fi = fieldInfoForMap(fd, fs)
case fd.Cardinality() == pref.Repeated:
fi = fieldInfoForVector(fd, fs)
case fd.Kind() != pref.MessageKind && fd.Kind() != pref.GroupKind:
fi = fieldInfoForScalar(fd, fs)
default:
fi = fieldInfoForMessage(fd, fs)
}
mi.fields[fd.Number()] = &fi
}
}