internal/impl: refactor MessageInfo
Changes made:
* Move MessageInfo.{methods,extensionFieldInfosMu,extensionFieldInfos}
to the coderMessageInfo type since they are fields all related to the
fast-path implementation, which is what the coderMessageInfo is for.
* Rename message_field.go -> message_reflect_field.go to make it obvious
from the file name that this only deals with the reflection implementation.
* Rename message_test.go -> message_reflect_test.go.
* Move reflection-specific implementation functions from message.go
to message_reflect.go. The intention is to make it such that message.go
is the entry point to message implementations and is agnostic towards
whether we are implementing reflection or the table-driven fast path.
Overall, there is no semantic changes. Just code movement.
Change-Id: I7743c39ba84dc63cd2a02934c3319285e16d6b1c
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/190100
Reviewed-by: Herbie Ong <herbie@google.com>
diff --git a/internal/impl/message.go b/internal/impl/message.go
index 9e1c3a3..2e35c51 100644
--- a/internal/impl/message.go
+++ b/internal/impl/message.go
@@ -20,13 +20,14 @@
// MessageInfo provides protobuf related functionality for a given Go type
// that represents a message. A given instance of MessageInfo is tied to
// exactly one Go type, which must be a pointer to a struct type.
+//
+// The exported fields must be populated before any methods are called
+// and cannot be mutated after set.
type MessageInfo struct {
// GoReflectType is the underlying message Go type and must be populated.
- // Once set, this field must never be mutated.
GoReflectType reflect.Type // pointer to struct
// Desc is the underlying message descriptor type and must be populated.
- // Once set, this field must never be mutated.
Desc pref.MessageDescriptor
// Exporter must be provided in a purego environment in order to provide
@@ -39,25 +40,8 @@
initMu sync.Mutex // protects all unexported fields
initDone uint32
- reflectMessageInfo
-
- // Information used by the fast-path methods.
- methods piface.Methods
- coderMessageInfo
-
- extensionFieldInfosMu sync.RWMutex
- extensionFieldInfos map[pref.ExtensionType]*extensionFieldInfo
-}
-
-type reflectMessageInfo struct {
- fields map[pref.FieldNumber]*fieldInfo
- oneofs map[pref.Name]*oneofInfo
-
- getUnknown func(pointer) pref.RawFields
- setUnknown func(pointer, pref.RawFields)
- extensionMap func(pointer) *extensionMap
-
- nilMessage atomicNilMessage
+ reflectMessageInfo // for reflection implementation
+ coderMessageInfo // for fast-path method implementations
}
// exporter is a function that returns a reference to the ith field of v,
@@ -81,8 +65,8 @@
}
func (mi *MessageInfo) init() {
- // This function is called in the hot path. Inline the sync.Once
- // logic, since allocating a closure for Once.Do is expensive.
+ // This function is called in the hot path. Inline the sync.Once logic,
+ // since allocating a closure for Once.Do is expensive.
// Keep init small to ensure that it can be inlined.
if atomic.LoadUint32(&mi.initDone) == 0 {
mi.initOnce()
@@ -100,12 +84,11 @@
if t.Kind() != reflect.Ptr && t.Elem().Kind() != reflect.Struct {
panic(fmt.Sprintf("got %v, want *struct kind", t))
}
+ t = t.Elem()
- si := mi.makeStructInfo(t.Elem())
- mi.makeKnownFieldsFunc(si)
- mi.makeUnknownFieldsFunc(t.Elem(), si)
- mi.makeExtensionFieldsFunc(t.Elem(), si)
- mi.makeMethods(t.Elem(), si)
+ si := mi.makeStructInfo(t)
+ mi.makeReflectFuncs(t, si)
+ mi.makeCoderMethods(t, si)
atomic.StoreUint32(&mi.initDone, 1)
}
@@ -215,89 +198,6 @@
return si
}
-// makeKnownFieldsFunc generates functions for operations that can be performed
-// on each protobuf message field. It takes in a reflect.Type representing the
-// Go struct and matches message fields with struct fields.
-//
-// This code assumes that the struct is well-formed and panics if there are
-// any discrepancies.
-func (mi *MessageInfo) makeKnownFieldsFunc(si structInfo) {
- mi.fields = map[pref.FieldNumber]*fieldInfo{}
- md := mi.Desc
- for i := 0; i < md.Fields().Len(); i++ {
- fd := md.Fields().Get(i)
- fs := si.fieldsByNumber[fd.Number()]
- var fi fieldInfo
- switch {
- case fd.ContainingOneof() != nil:
- fi = fieldInfoForOneof(fd, si.oneofsByName[fd.ContainingOneof().Name()], mi.Exporter, si.oneofWrappersByNumber[fd.Number()])
- case fd.IsMap():
- fi = fieldInfoForMap(fd, fs, mi.Exporter)
- case fd.IsList():
- fi = fieldInfoForList(fd, fs, mi.Exporter)
- case fd.IsWeak():
- fi = fieldInfoForWeakMessage(fd, si.weakOffset)
- case fd.Kind() == pref.MessageKind || fd.Kind() == pref.GroupKind:
- fi = fieldInfoForMessage(fd, fs, mi.Exporter)
- default:
- fi = fieldInfoForScalar(fd, fs, mi.Exporter)
- }
- mi.fields[fd.Number()] = &fi
- }
-
- mi.oneofs = map[pref.Name]*oneofInfo{}
- for i := 0; i < md.Oneofs().Len(); i++ {
- od := md.Oneofs().Get(i)
- mi.oneofs[od.Name()] = makeOneofInfo(od, si.oneofsByName[od.Name()], mi.Exporter, si.oneofWrappersByType)
- }
-}
-
-func (mi *MessageInfo) makeUnknownFieldsFunc(t reflect.Type, si structInfo) {
- mi.getUnknown = func(pointer) pref.RawFields { return nil }
- mi.setUnknown = func(pointer, pref.RawFields) { return }
- if si.unknownOffset.IsValid() {
- mi.getUnknown = func(p pointer) pref.RawFields {
- if p.IsNil() {
- return nil
- }
- rv := p.Apply(si.unknownOffset).AsValueOf(unknownFieldsType)
- return pref.RawFields(*rv.Interface().(*[]byte))
- }
- mi.setUnknown = func(p pointer, b pref.RawFields) {
- if p.IsNil() {
- panic("invalid SetUnknown on nil Message")
- }
- rv := p.Apply(si.unknownOffset).AsValueOf(unknownFieldsType)
- *rv.Interface().(*[]byte) = []byte(b)
- }
- } else {
- mi.getUnknown = func(pointer) pref.RawFields {
- return nil
- }
- mi.setUnknown = func(p pointer, _ pref.RawFields) {
- if p.IsNil() {
- panic("invalid SetUnknown on nil Message")
- }
- }
- }
-}
-
-func (mi *MessageInfo) makeExtensionFieldsFunc(t reflect.Type, si structInfo) {
- if si.extensionOffset.IsValid() {
- mi.extensionMap = func(p pointer) *extensionMap {
- if p.IsNil() {
- return (*extensionMap)(nil)
- }
- v := p.Apply(si.extensionOffset).AsValueOf(extensionFieldsType)
- return (*extensionMap)(v.Interface().(*map[int32]ExtensionField))
- }
- } else {
- mi.extensionMap = func(pointer) *extensionMap {
- return (*extensionMap)(nil)
- }
- }
-}
-
func (mi *MessageInfo) GoType() reflect.Type {
return mi.GoReflectType
}