Added "final" to generated types to block inheritance.

People sometimes accidentally inherit from these types.

Bug: 18224703
Change-Id: Ia09489a834ac4941f9b4a46f240cbdcf456f03a1
Tested: on Windows and Linux.

include/flatbuffers/flatbuffers.h

@@ -61,6 +61,13 @@
 #define FLATBUFFERS_STRING_EXPAND(X) #X
 #define FLATBUFFERS_STRING(X) FLATBUFFERS_STRING_EXPAND(X)
 
+#if (!defined(_MSC_VER) || _MSC_VER > 1600) && \
+    (!defined(__GNUC__) || (__GNUC__ * 100 + __GNUC_MINOR__ >= 407))
+  #define FLATBUFFERS_FINAL_CLASS final
+#else
+  #define FLATBUFFERS_FINAL_CLASS
+#endif
+
 namespace flatbuffers {
 
 // Our default offset / size type, 32bit on purpose on 64bit systems.
@@ -394,7 +401,7 @@ inline size_t PaddingBytes(size_t buf_size, size_t scalar_size) {
 // AddElement/EndTable, or the builtin CreateString/CreateVector functions.
 // Do this is depth-first order to build up a tree to the root.
 // Finish() wraps up the buffer ready for transport.
-class FlatBufferBuilder {
+class FlatBufferBuilder FLATBUFFERS_FINAL_CLASS {
  public:
   explicit FlatBufferBuilder(uoffset_t initial_size = 1024,
                              const simple_allocator *allocator = nullptr)
@@ -715,7 +722,7 @@ inline bool BufferHasIdentifier(const void *buf, const char *identifier) {
 }
 
 // Helper class to verify the integrity of a FlatBuffer
-class Verifier {
+class Verifier FLATBUFFERS_FINAL_CLASS {
  public:
   Verifier(const uint8_t *buf, size_t buf_len, size_t _max_depth = 64,
            size_t _max_tables = 1000000)
@@ -833,7 +840,7 @@ class Verifier {
 // always have all members present and do not support forwards/backwards
 // compatible extensions.
 
-class Struct {
+class Struct FLATBUFFERS_FINAL_CLASS {
  public:
   template<typename T> T GetField(uoffset_t o) const {
     return ReadScalar<T>(&data_[o]);

samples/monster_generated.h

@@ -37,7 +37,7 @@ inline const char **EnumNamesAny() {
 
 inline const char *EnumNameAny(Any e) { return EnumNamesAny()[e]; }
 
-inline bool VerifyAny(flatbuffers::Verifier &verifier, const void *union_obj, uint8_t type);
+inline bool VerifyAny(flatbuffers::Verifier &verifier, const void *union_obj, Any type);
 
 MANUALLY_ALIGNED_STRUCT(4) Vec3 {
  private:
@@ -110,7 +110,7 @@ inline flatbuffers::Offset<Monster> CreateMonster(flatbuffers::FlatBufferBuilder
   return builder_.Finish();
 }
 
-inline bool VerifyAny(flatbuffers::Verifier &verifier, const void *union_obj, uint8_t type) {
+inline bool VerifyAny(flatbuffers::Verifier &verifier, const void *union_obj, Any type) {
   switch (type) {
     case Any_NONE: return true;
     case Any_Monster: return verifier.VerifyTable(reinterpret_cast<const Monster *>(union_obj));

src/idl_gen_cpp.cpp

@@ -208,7 +208,8 @@ static void GenTable(const Parser &parser, StructDef &struct_def,
   // Generate an accessor struct, with methods of the form:
   // type name() const { return GetField<type>(offset, defaultval); }
   GenComment(struct_def.doc_comment, code_ptr);
-  code += "struct " + struct_def.name + " : private flatbuffers::Table";
+  code += "struct " + struct_def.name;
+  code += " FLATBUFFERS_FINAL_CLASS : private flatbuffers::Table";
   code += " {\n";
   for (auto it = struct_def.fields.vec.begin();
        it != struct_def.fields.vec.end();
@@ -414,7 +415,7 @@ static void GenStruct(const Parser &parser, StructDef &struct_def,
   // platforms.
   GenComment(struct_def.doc_comment, code_ptr);
   code += "MANUALLY_ALIGNED_STRUCT(" + NumToString(struct_def.minalign) + ") ";
-  code += struct_def.name + " {\n private:\n";
+  code += struct_def.name + " FLATBUFFERS_FINAL_CLASS {\n private:\n";
   int padding_id = 0;
   for (auto it = struct_def.fields.vec.begin();
        it != struct_def.fields.vec.end();

tests/monster_test_generated.h

@@ -46,7 +46,7 @@ inline const char *EnumNameAny(Any e) { return EnumNamesAny()[e]; }
 
 inline bool VerifyAny(flatbuffers::Verifier &verifier, const void *union_obj, Any type);
 
-MANUALLY_ALIGNED_STRUCT(2) Test {
+MANUALLY_ALIGNED_STRUCT(2) Test FLATBUFFERS_FINAL_CLASS {
  private:
   int16_t a_;
   int8_t b_;
@@ -61,7 +61,7 @@ MANUALLY_ALIGNED_STRUCT(2) Test {
 };
 STRUCT_END(Test, 4);
 
-MANUALLY_ALIGNED_STRUCT(16) Vec3 {
+MANUALLY_ALIGNED_STRUCT(16) Vec3 FLATBUFFERS_FINAL_CLASS {
  private:
   float x_;
   float y_;
@@ -86,7 +86,7 @@ MANUALLY_ALIGNED_STRUCT(16) Vec3 {
 };
 STRUCT_END(Vec3, 32);
 
-struct Stat : private flatbuffers::Table {
+struct Stat FLATBUFFERS_FINAL_CLASS : private flatbuffers::Table {
   const flatbuffers::String *id() const { return GetPointer<const flatbuffers::String *>(4); }
   int64_t val() const { return GetField<int64_t>(6, 0); }
   bool Verify(flatbuffers::Verifier &verifier) const {
@@ -120,7 +120,7 @@ inline flatbuffers::Offset<Stat> CreateStat(flatbuffers::FlatBufferBuilder &_fbb
   return builder_.Finish();
 }
 
-struct Monster : private flatbuffers::Table {
+struct Monster FLATBUFFERS_FINAL_CLASS : private flatbuffers::Table {
   const Vec3 *pos() const { return GetStruct<const Vec3 *>(4); }
   int16_t mana() const { return GetField<int16_t>(6, 150); }
   int16_t hp() const { return GetField<int16_t>(8, 100); }