Generate v2 table definition.

PiperOrigin-RevId: 674463427

src/google/protobuf/compiler/cpp/helpers.cc

@@ -1169,6 +1169,17 @@ bool HasMapFields(const FileDescriptor* file) {
   return false;
 }
 
+bool HasV2Table(const Descriptor* descriptor) {
+  return false;
+}
+
+bool HasV2Table(const FileDescriptor* file) {
+  for (int i = 0; i < file->message_type_count(); ++i) {
+    if (HasV2Table(file->message_type(i))) return true;
+  }
+  return false;
+}
+
 static bool HasEnumDefinitions(const Descriptor* message_type) {
   if (message_type->enum_type_count() > 0) return true;
   for (int i = 0; i < message_type->nested_type_count(); ++i) {

src/google/protobuf/compiler/cpp/helpers.h

@@ -467,6 +467,12 @@ bool HasMapFields(const FileDescriptor* file);
 // Does this file have any enum type definitions?
 bool HasEnumDefinitions(const FileDescriptor* file);
 
+// Returns true if a message in the file can have v2 table.
+bool HasV2Table(const FileDescriptor* file);
+
+// Returns true if a message (descriptor) can have v2 table.
+bool HasV2Table(const Descriptor* descriptor);
+
 // Does this file have generated parsing, serialization, and other
 // standard methods for which reflection-based fallback implementations exist?
 inline bool HasGeneratedMethods(const FileDescriptor* file,

src/google/protobuf/compiler/cpp/message.cc

@@ -1366,7 +1366,9 @@ void MessageGenerator::GenerateMapEntryClassDefinition(io::Printer* p) {
         }},
        {"decl_annotate", [&] { GenerateAnnotationDecl(p); }},
        {"parse_decls",
-        [&] { parse_function_generator_->GenerateDataDecls(p); }}},
+        [&] {
+          parse_function_generator_->GenerateDataDecls(p);
+        }}},
       R"cc(
         class $classname$ final
             : public ::$proto_ns$::internal::MapEntry<
@@ -2026,7 +2028,10 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* p) {
             )cc");
           }
         }},
-       {"decl_data", [&] { parse_function_generator_->GenerateDataDecls(p); }},
+       {"decl_data",
+        [&] {
+          parse_function_generator_->GenerateDataDecls(p);
+        }},
        {"post_loop_handler",
         [&] {
           if (!NeedsPostLoopHandler(descriptor_, options_)) return;
@@ -4040,6 +4045,9 @@ void MessageGenerator::GenerateClassData(io::Printer* p) {
             {"is_initialized", is_initialized},
             {"pin_weak_descriptor", pin_weak_descriptor},
             {"custom_vtable_methods", custom_vtable_methods},
+            {"v2_msg_table",
+             [&] {
+             }},
             {"tracker_on_get_metadata",
              [&] {
                if (HasTracker(descriptor_, options_)) {
@@ -4071,6 +4079,7 @@ void MessageGenerator::GenerateClassData(io::Printer* p) {
 #endif  // PROTOBUF_CUSTOM_VTABLE
                       PROTOBUF_FIELD_OFFSET($classname$, $cached_size$),
                       false,
+                      $v2_msg_table$,
                   },
                   &$classname$::kDescriptorMethods,
                   &$desc_table$,
@@ -4090,6 +4099,9 @@ void MessageGenerator::GenerateClassData(io::Printer* p) {
             {"on_demand_register_arena_dtor", on_demand_register_arena_dtor},
             {"is_initialized", is_initialized},
             {"custom_vtable_methods", custom_vtable_methods},
+            {"v2_msg_table",
+             [&] {
+             }},
         },
         R"cc(
           PROTOBUF_CONSTINIT
@@ -4109,6 +4121,7 @@ void MessageGenerator::GenerateClassData(io::Printer* p) {
 #endif  // PROTOBUF_CUSTOM_VTABLE
                       PROTOBUF_FIELD_OFFSET($classname$, $cached_size$),
                       true,
+                      $v2_msg_table$,
                   },
                   "$full_name$",
           };

src/google/protobuf/message_lite.h

@@ -68,6 +68,13 @@ class ZeroCopyInputStream;
 class ZeroCopyOutputStream;
 
 }  // namespace io
+
+namespace compiler {
+namespace cpp {
+class MessageTableTester;
+}  // namespace cpp
+}  // namespace compiler
+
 namespace internal {
 
 class MessageCreator {
@@ -712,15 +719,15 @@ class PROTOBUF_EXPORT MessageLite {
     // In normal mode we have the small constructor to avoid the cost in
     // codegen.
 #if !defined(PROTOBUF_CUSTOM_VTABLE)
-    constexpr ClassData(const MessageLite* prototype,
-                        const internal::TcParseTableBase* tc_table,
-                        void (*on_demand_register_arena_dtor)(MessageLite&,
-                                                              Arena&),
-                        bool (*is_initialized)(const MessageLite&),
-                        void (*merge_to_from)(MessageLite& to,
-                                              const MessageLite& from_msg),
-                        internal::MessageCreator message_creator,
-                        uint32_t cached_size_offset, bool is_lite)
+    constexpr ClassData(
+        const MessageLite* prototype,
+        const internal::TcParseTableBase* tc_table,
+        void (*on_demand_register_arena_dtor)(MessageLite&, Arena&),
+        bool (*is_initialized)(const MessageLite&),
+        void (*merge_to_from)(MessageLite& to, const MessageLite& from_msg),
+        internal::MessageCreator message_creator, uint32_t cached_size_offset,
+        bool is_lite
+        )
         : prototype(prototype),
           tc_table(tc_table),
           on_demand_register_arena_dtor(on_demand_register_arena_dtor),
@@ -728,7 +735,9 @@ class PROTOBUF_EXPORT MessageLite {
           merge_to_from(merge_to_from),
           message_creator(message_creator),
           cached_size_offset(cached_size_offset),
-          is_lite(is_lite) {}
+          is_lite(is_lite)
+    {
+    }
 #endif  // !PROTOBUF_CUSTOM_VTABLE
 
     // But we always provide the full constructor even in normal mode to make
@@ -745,7 +754,8 @@ class PROTOBUF_EXPORT MessageLite {
         size_t (*byte_size_long)(const MessageLite&),
         uint8_t* (*serialize)(const MessageLite& msg, uint8_t* ptr,
                               io::EpsCopyOutputStream* stream),
-        uint32_t cached_size_offset, bool is_lite)
+        uint32_t cached_size_offset, bool is_lite
+        )
         : prototype(prototype),
           tc_table(tc_table),
           on_demand_register_arena_dtor(on_demand_register_arena_dtor),
@@ -759,7 +769,8 @@ class PROTOBUF_EXPORT MessageLite {
           serialize(serialize),
 #endif  // PROTOBUF_CUSTOM_VTABLE
           cached_size_offset(cached_size_offset),
-          is_lite(is_lite) {
+          is_lite(is_lite)
+    {
     }
 
     const ClassDataFull& full() const {
@@ -930,6 +941,7 @@ class PROTOBUF_EXPORT MessageLite {
   friend class Message;
   friend class Reflection;
   friend class TypeId;
+  friend class compiler::cpp::MessageTableTester;
   friend class internal::DescriptorPoolExtensionFinder;
   friend class internal::ExtensionSet;
   friend class internal::LazyField;
@@ -957,6 +969,13 @@ class PROTOBUF_EXPORT MessageLite {
   // `operator delete`
   void DeleteInstance();
 
+  // For tests that need to inspect private _oneof_case_. It is the callers
+  // responsibility to ensure T has the right member.
+  template <typename T>
+  static uint32_t GetOneofCaseOffsetForTesting() {
+    return offsetof(T, _impl_._oneof_case_);
+  }
+
   template <typename T, const void* ptr = T::_raw_default_instance_>
   static constexpr auto GetStrongPointerForTypeImpl(int) {
     return ptr;