Struct typetable (#5291)

* C++: Generate MiniReflectTypeTable for Structs as well as Tables

* Update generated code

* add test

samples/monster_generated.h

@@ -174,6 +174,9 @@ FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(4) Vec3 FLATBUFFERS_FINAL_CLASS {
   float z_;
 
  public:
+  static const flatbuffers::TypeTable *MiniReflectTypeTable() {
+    return Vec3TypeTable();
+  }
   Vec3() {
     memset(static_cast<void *>(this), 0, sizeof(Vec3));
   }

src/idl_gen_cpp.cpp

@@ -2684,6 +2684,15 @@ class CppGenerator : public BaseGenerator {
     // Generate GetFullyQualifiedName
     code_ += "";
     code_ += " public:";
+
+    // Make TypeTable accessible via the generated struct.
+    if (parser_.opts.mini_reflect != IDLOptions::kNone) {
+      code_ +=
+          "  static const flatbuffers::TypeTable *MiniReflectTypeTable() {";
+      code_ += "    return {{STRUCT_NAME}}TypeTable();";
+      code_ += "  }";
+    }
+
     GenFullyQualifiedNameGetter(struct_def, Name(struct_def));
 
     // Generate a default constructor.

tests/monster_test_generated.h

@@ -542,6 +542,9 @@ FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(2) Test FLATBUFFERS_FINAL_CLASS {
   int8_t padding0__;
 
  public:
+  static const flatbuffers::TypeTable *MiniReflectTypeTable() {
+    return TestTypeTable();
+  }
   Test() {
     memset(static_cast<void *>(this), 0, sizeof(Test));
   }
@@ -590,6 +593,9 @@ FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(8) Vec3 FLATBUFFERS_FINAL_CLASS {
   int16_t padding2__;
 
  public:
+  static const flatbuffers::TypeTable *MiniReflectTypeTable() {
+    return Vec3TypeTable();
+  }
   Vec3() {
     memset(static_cast<void *>(this), 0, sizeof(Vec3));
   }
@@ -667,6 +673,9 @@ FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(4) Ability FLATBUFFERS_FINAL_CLASS {
   uint32_t distance_;
 
  public:
+  static const flatbuffers::TypeTable *MiniReflectTypeTable() {
+    return AbilityTypeTable();
+  }
   Ability() {
     memset(static_cast<void *>(this), 0, sizeof(Ability));
   }

tests/namespace_test/namespace_test1_generated.h

@@ -56,6 +56,9 @@ FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(4) StructInNestedNS FLATBUFFERS_FINAL_CLASS
   int32_t b_;
 
  public:
+  static const flatbuffers::TypeTable *MiniReflectTypeTable() {
+    return StructInNestedNSTypeTable();
+  }
   StructInNestedNS() {
     memset(static_cast<void *>(this), 0, sizeof(StructInNestedNS));
   }

tests/test.cpp

@@ -894,6 +894,17 @@ void MiniReflectFlatBuffersTest(uint8_t *flatbuf) {
       "test5: [ { a: 10, b: 20 }, { a: 30, b: 40 } ], "
       "vector_of_enums: [ Blue, Green ] "
       "}");
+
+  Test test(16, 32);
+  Vec3 vec(1,2,3, 1.5, Color_Red, test);
+  flatbuffers::FlatBufferBuilder vec_builder;
+  vec_builder.Finish(vec_builder.CreateStruct(vec));
+  auto vec_buffer = vec_builder.Release();
+  auto vec_str = flatbuffers::FlatBufferToString(vec_buffer.data(),
+                                                 Vec3::MiniReflectTypeTable());
+  TEST_EQ_STR(
+      vec_str.c_str(),
+      "{ x: 1.0, y: 2.0, z: 3.0, test1: 1.5, test2: Red, test3: { a: 16, b: 32 } }");
 }
 
 // Parse a .proto schema, output as .fbs

tests/union_vector/union_vector_generated.h

@@ -197,6 +197,9 @@ FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(4) Rapunzel FLATBUFFERS_FINAL_CLASS {
   int32_t hair_length_;
 
  public:
+  static const flatbuffers::TypeTable *MiniReflectTypeTable() {
+    return RapunzelTypeTable();
+  }
   Rapunzel() {
     memset(static_cast<void *>(this), 0, sizeof(Rapunzel));
   }
@@ -227,6 +230,9 @@ FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(4) BookReader FLATBUFFERS_FINAL_CLASS {
   int32_t books_read_;
 
  public:
+  static const flatbuffers::TypeTable *MiniReflectTypeTable() {
+    return BookReaderTypeTable();
+  }
   BookReader() {
     memset(static_cast<void *>(this), 0, sizeof(BookReader));
   }