internal/legacy: drop legacy prefix

The legacy prefix made sense when this functionality was part of impl.
Now that it is in its own package called legacy, the legacy prefix is silly.

Change-Id: I9e6ddb6185ce1f701e02768b505e6a05f3986f77
Reviewed-on: https://go-review.googlesource.com/c/152543
Reviewed-by: Herbie Ong <herbie@google.com>
diff --git a/internal/legacy/enum.go b/internal/legacy/enum.go
index 86cc7f2..1f5d391 100644
--- a/internal/legacy/enum.go
+++ b/internal/legacy/enum.go
@@ -16,18 +16,18 @@
 	ptype "github.com/golang/protobuf/v2/reflect/prototype"
 )
 
-// legacyWrapEnum wraps v as a protoreflect.ProtoEnum,
+// wrapEnum wraps v as a protoreflect.ProtoEnum,
 // where v must be a int32 kind and not implement the v2 API already.
-func legacyWrapEnum(v reflect.Value) pref.ProtoEnum {
-	et := legacyLoadEnumType(v.Type())
+func wrapEnum(v reflect.Value) pref.ProtoEnum {
+	et := loadEnumType(v.Type())
 	return et.New(pref.EnumNumber(v.Int()))
 }
 
 var enumTypeCache sync.Map // map[reflect.Type]protoreflect.EnumType
 
-// legacyLoadEnumType dynamically loads a protoreflect.EnumType for t,
+// loadEnumType dynamically loads a protoreflect.EnumType for t,
 // where t must be an int32 kind and not implement the v2 API already.
-func legacyLoadEnumType(t reflect.Type) pref.EnumType {
+func loadEnumType(t reflect.Type) pref.EnumType {
 	// Fast-path: check if a EnumType is cached for this concrete type.
 	if et, ok := enumTypeCache.Load(t); ok {
 		return et.(pref.EnumType)
@@ -35,12 +35,12 @@
 
 	// Slow-path: derive enum descriptor and initialize EnumType.
 	var m sync.Map // map[protoreflect.EnumNumber]proto.Enum
-	ed := legacyLoadEnumDesc(t)
+	ed := loadEnumDesc(t)
 	et := ptype.GoEnum(ed, func(et pref.EnumType, n pref.EnumNumber) pref.ProtoEnum {
 		if e, ok := m.Load(n); ok {
 			return e.(pref.ProtoEnum)
 		}
-		e := &legacyEnumWrapper{num: n, pbTyp: et, goTyp: t}
+		e := &enumWrapper{num: n, pbTyp: et, goTyp: t}
 		m.Store(n, e)
 		return e
 	})
@@ -48,40 +48,40 @@
 	return et.(pref.EnumType)
 }
 
-type legacyEnumWrapper struct {
+type enumWrapper struct {
 	num   pref.EnumNumber
 	pbTyp pref.EnumType
 	goTyp reflect.Type
 }
 
-func (e *legacyEnumWrapper) Number() pref.EnumNumber {
+func (e *enumWrapper) Number() pref.EnumNumber {
 	return e.num
 }
-func (e *legacyEnumWrapper) Type() pref.EnumType {
+func (e *enumWrapper) Type() pref.EnumType {
 	return e.pbTyp
 }
-func (e *legacyEnumWrapper) ProtoReflect() pref.Enum {
+func (e *enumWrapper) ProtoReflect() pref.Enum {
 	return e
 }
-func (e *legacyEnumWrapper) ProtoUnwrap() interface{} {
+func (e *enumWrapper) ProtoUnwrap() interface{} {
 	v := reflect.New(e.goTyp).Elem()
 	v.SetInt(int64(e.num))
 	return v.Interface()
 }
 
 var (
-	_ pref.Enum        = (*legacyEnumWrapper)(nil)
-	_ pref.ProtoEnum   = (*legacyEnumWrapper)(nil)
-	_ pvalue.Unwrapper = (*legacyEnumWrapper)(nil)
+	_ pref.Enum        = (*enumWrapper)(nil)
+	_ pref.ProtoEnum   = (*enumWrapper)(nil)
+	_ pvalue.Unwrapper = (*enumWrapper)(nil)
 )
 
 var enumDescCache sync.Map // map[reflect.Type]protoreflect.EnumDescriptor
 
 var enumNumberType = reflect.TypeOf(pref.EnumNumber(0))
 
-// legacyLoadEnumDesc returns an EnumDescriptor derived from the Go type,
+// loadEnumDesc returns an EnumDescriptor derived from the Go type,
 // which must be an int32 kind and not implement the v2 API already.
-func legacyLoadEnumDesc(t reflect.Type) pref.EnumDescriptor {
+func loadEnumDesc(t reflect.Type) pref.EnumDescriptor {
 	// Fast-path: check if an EnumDescriptor is cached for this concrete type.
 	if v, ok := enumDescCache.Load(t); ok {
 		return v.(pref.EnumDescriptor)
@@ -101,9 +101,9 @@
 	if _, ok := ev.(pref.ProtoEnum); ok {
 		panic(fmt.Sprintf("%v already implements proto.Enum", t))
 	}
-	if ed, ok := ev.(legacyEnum); ok {
+	if ed, ok := ev.(enumV1); ok {
 		b, idxs := ed.EnumDescriptor()
-		fd := legacyLoadFileDesc(b)
+		fd := loadFileDesc(b)
 
 		// Derive syntax.
 		switch fd.GetSyntax() {
@@ -138,7 +138,7 @@
 			})
 		}
 	} else {
-		// If the type does not implement legacyEnum, then there is no reliable
+		// If the type does not implement enumV1, then there is no reliable
 		// way to derive the original protobuf type information.
 		// We are unable to use the global enum registry since it is
 		// unfortunately keyed by the full name, which we do not know.