[C++] remove static_cast expression (#5440)

* [C++] remove static_cast expression

* [C++] Add unit test for native_type usage

* [C++] Add flatc compilation for native_type_test.fbs

* [C++] update CMakeLists to compile native_type_test.fbs properly

* Update BUILD file for bazel

* [C++] Add generated native_type_test_generated.h and fix arguments for flatc according to CMakeList

* [C++] remove "= default" from constructor to support old compilers

* Update BUILD file for bazel, attempt 2

* [C++] Workaround for MSVC 2010 for the issue with std::vector and explicitly aligned custom data types

* Update BUILD file for bazel, attempt 3

* Update BUILD file for bazel, attempt 4

* Update BUILD file for bazel, attempt 5

* Update BUILD file for bazel, attempt 6

* [C++] Workaround for MSVC 2010 for the issue with std::vector and explicitly aligned custom data types Part 2

* [C++] Keep only one optional parameter to compile_flatbuffers_schema_to_cpp_opt

* native_type_test.fbs style corrected

* [C++] Code style modifications

* [C++] Fix flatc arguments in CMakeLists

* [C++] Remove --gen-compare from default parameters for flatc in CMakeLists

* [C++] Change Vector3D fields from double to float, to have alignment eq. 4 (to support MSVC 2010), plus minor review fix

* [C++] Remove one more #if !defined

* [C++] Restore version with correct static_cast, add the same fix for SortedStructs

* Revert "[C++] Restore version with correct static_cast, add the same fix for SortedStructs"

This reverts commit d61f4d6628.

* [C++] Fix Android.mk

BUILD

@@ -137,6 +137,8 @@ cc_test(
         "src/util.cpp",
         "tests/namespace_test/namespace_test1_generated.h",
         "tests/namespace_test/namespace_test2_generated.h",
+        "tests/native_type_test_impl.h",
+        "tests/native_type_test_impl.cpp",
         "tests/test.cpp",
         "tests/test_assert.cpp",
         "tests/test_assert.h",
@@ -168,12 +170,17 @@ cc_test(
         ":tests/arrays_test.bfbs",
         ":tests/arrays_test.fbs",
         ":tests/arrays_test.golden",
+        ":tests/native_type_test.fbs",
+    ],
+    includes = [
+        "include/",
+        "tests/",
     ],
-    includes = ["include/"],
     deps = [
         ":monster_extra_cc_fbs",
         ":monster_test_cc_fbs",
         ":arrays_test_cc_fbs",
+        ":native_type_test_cc_fbs",
     ],
 )
 
@@ -206,3 +213,13 @@ flatbuffer_cc_library(
         "--cpp-ptr-type flatbuffers::unique_ptr",
         "--scoped-enums" ],
 )
+
+flatbuffer_cc_library(
+    name = "native_type_test_cc_fbs",
+    srcs = ["tests/native_type_test.fbs"],
+    flatc_args = [
+        "--gen-object-api",
+        "--gen-mutable",
+        "--cpp-ptr-type flatbuffers::unique_ptr" ],
+)
+

CMakeLists.txt

@@ -118,10 +118,14 @@ set(FlatBuffers_Tests_SRCS
   tests/test_assert.cpp
   tests/test_builder.h
   tests/test_builder.cpp
+  tests/native_type_test_impl.h
+  tests/native_type_test_impl.cpp
   # file generate by running compiler on tests/monster_test.fbs
   ${CMAKE_CURRENT_BINARY_DIR}/tests/monster_test_generated.h
   # file generate by running compiler on tests/arrays_test.fbs
   ${CMAKE_CURRENT_BINARY_DIR}/tests/arrays_test_generated.h
+  # file generate by running compiler on tests/native_type_test.fbs
+  ${CMAKE_CURRENT_BINARY_DIR}/tests/native_type_test_generated.h
 )
 
 set(FlatBuffers_Sample_Binary_SRCS
@@ -311,8 +315,8 @@ function(compile_flatbuffers_schema_to_cpp_opt SRC_FBS OPT)
   string(REGEX REPLACE "\\.fbs$" "_generated.h" GEN_HEADER ${SRC_FBS})
   add_custom_command(
     OUTPUT ${GEN_HEADER}
-    COMMAND "${FLATBUFFERS_FLATC_EXECUTABLE}" -c --no-includes --gen-mutable
-            --gen-object-api --gen-compare -o "${SRC_FBS_DIR}"
+    COMMAND "${FLATBUFFERS_FLATC_EXECUTABLE}" -c --gen-mutable
+            --gen-object-api -o "${SRC_FBS_DIR}"
             --cpp-ptr-type flatbuffers::unique_ptr # Used to test with C++98 STLs
             --reflect-names ${OPT}
             -I "${CMAKE_CURRENT_SOURCE_DIR}/tests/include_test"
@@ -321,7 +325,7 @@ function(compile_flatbuffers_schema_to_cpp_opt SRC_FBS OPT)
 endfunction()
 
 function(compile_flatbuffers_schema_to_cpp SRC_FBS)
-    compile_flatbuffers_schema_to_cpp_opt(${SRC_FBS} "")
+    compile_flatbuffers_schema_to_cpp_opt(${SRC_FBS} "--no-includes;--gen-compare")
 endfunction()
 
 function(compile_flatbuffers_schema_to_binary SRC_FBS)
@@ -336,6 +340,7 @@ endfunction()
 
 if(FLATBUFFERS_BUILD_TESTS)
   compile_flatbuffers_schema_to_cpp(tests/monster_test.fbs)
+  compile_flatbuffers_schema_to_cpp_opt(tests/native_type_test.fbs "")
   compile_flatbuffers_schema_to_cpp_opt(tests/arrays_test.fbs --scoped-enums)
   include_directories(${CMAKE_CURRENT_BINARY_DIR}/tests)
   add_executable(flattests ${FlatBuffers_Tests_SRCS})

android/jni/Android.mk

@@ -51,6 +51,8 @@ LOCAL_SRC_FILES := android/jni/main.cpp \
                    tests/test_builder.h \
                    tests/test_assert.cpp \
                    tests/test_builder.cpp \
+                   tests/native_type_test_impl.h \
+                   tests/native_type_test_impl.cpp \
                    src/idl_gen_fbs.cpp \
                    src/idl_gen_general.cpp
 LOCAL_LDLIBS := -llog -landroid -latomic

include/flatbuffers/flatbuffers.h

@@ -1653,9 +1653,8 @@ class FlatBufferBuilder {
   Offset<Vector<const T *>> CreateVectorOfNativeStructs(const S *v,
                                                         size_t len) {
     extern T Pack(const S &);
-    typedef T (*Pack_t)(const S &);
     std::vector<T> vv(len);
-    std::transform(v, v + len, vv.begin(), static_cast<Pack_t>(&Pack));
+    std::transform(v, v + len, vv.begin(), Pack);
     return CreateVectorOfStructs<T>(vv.data(), vv.size());
   }
 

tests/generate_code.bat

@@ -22,6 +22,7 @@ if "%1"=="-b" set buildtype=%2
 ..\%buildtype%\flatc.exe -b --schema --bfbs-comments --bfbs-builtins -I include_test arrays_test.fbs || goto FAIL
 ..\%buildtype%\flatc.exe --jsonschema --schema -I include_test monster_test.fbs || goto FAIL
 ..\%buildtype%\flatc.exe --cpp --java --csharp --python --gen-mutable --reflect-names --gen-object-api --gen-compare --no-includes --scoped-enums --jsonschema --cpp-ptr-type flatbuffers::unique_ptr arrays_test.fbs || goto FAIL
+..\%buildtype%\flatc.exe --cpp --gen-mutable --gen-object-api --reflect-names --cpp-ptr-type flatbuffers::unique_ptr native_type_test.fbs || goto FAIL
 
 IF NOT "%MONSTER_EXTRA%"=="skip" (
   @echo Generate MosterExtra

tests/native_type_test.fbs

@@ -0,0 +1,15 @@
+native_include "native_type_test_impl.h";
+
+namespace Geometry;
+
+struct Vector3D (native_type:"Native::Vector3D") {
+  x:float;
+  y:float;
+  z:float;
+}
+
+table ApplicationData {
+  vectors:[Vector3D];
+}
+
+root_type ApplicationData;

tests/native_type_test_generated.h

@@ -0,0 +1,238 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+
+
+#ifndef FLATBUFFERS_GENERATED_NATIVETYPETEST_GEOMETRY_H_
+#define FLATBUFFERS_GENERATED_NATIVETYPETEST_GEOMETRY_H_
+
+#include "flatbuffers/flatbuffers.h"
+
+#include "native_type_test_impl.h"
+
+namespace Geometry {
+
+struct Vector3D;
+
+struct ApplicationData;
+struct ApplicationDataT;
+
+inline const flatbuffers::TypeTable *Vector3DTypeTable();
+
+inline const flatbuffers::TypeTable *ApplicationDataTypeTable();
+
+FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(4) Vector3D FLATBUFFERS_FINAL_CLASS {
+ private:
+  float x_;
+  float y_;
+  float z_;
+
+ public:
+  static const flatbuffers::TypeTable *MiniReflectTypeTable() {
+    return Vector3DTypeTable();
+  }
+  Vector3D() {
+    memset(static_cast<void *>(this), 0, sizeof(Vector3D));
+  }
+  Vector3D(float _x, float _y, float _z)
+      : x_(flatbuffers::EndianScalar(_x)),
+        y_(flatbuffers::EndianScalar(_y)),
+        z_(flatbuffers::EndianScalar(_z)) {
+  }
+  float x() const {
+    return flatbuffers::EndianScalar(x_);
+  }
+  void mutate_x(float _x) {
+    flatbuffers::WriteScalar(&x_, _x);
+  }
+  float y() const {
+    return flatbuffers::EndianScalar(y_);
+  }
+  void mutate_y(float _y) {
+    flatbuffers::WriteScalar(&y_, _y);
+  }
+  float z() const {
+    return flatbuffers::EndianScalar(z_);
+  }
+  void mutate_z(float _z) {
+    flatbuffers::WriteScalar(&z_, _z);
+  }
+};
+FLATBUFFERS_STRUCT_END(Vector3D, 12);
+
+struct ApplicationDataT : public flatbuffers::NativeTable {
+  typedef ApplicationData TableType;
+  std::vector<Native::Vector3D> vectors;
+  ApplicationDataT() {
+  }
+};
+
+struct ApplicationData FLATBUFFERS_FINAL_CLASS : private flatbuffers::Table {
+  typedef ApplicationDataT NativeTableType;
+  static const flatbuffers::TypeTable *MiniReflectTypeTable() {
+    return ApplicationDataTypeTable();
+  }
+  enum FlatBuffersVTableOffset FLATBUFFERS_VTABLE_UNDERLYING_TYPE {
+    VT_VECTORS = 4
+  };
+  const flatbuffers::Vector<const Geometry::Vector3D *> *vectors() const {
+    return GetPointer<const flatbuffers::Vector<const Geometry::Vector3D *> *>(VT_VECTORS);
+  }
+  flatbuffers::Vector<const Geometry::Vector3D *> *mutable_vectors() {
+    return GetPointer<flatbuffers::Vector<const Geometry::Vector3D *> *>(VT_VECTORS);
+  }
+  bool Verify(flatbuffers::Verifier &verifier) const {
+    return VerifyTableStart(verifier) &&
+           VerifyOffset(verifier, VT_VECTORS) &&
+           verifier.VerifyVector(vectors()) &&
+           verifier.EndTable();
+  }
+  ApplicationDataT *UnPack(const flatbuffers::resolver_function_t *_resolver = nullptr) const;
+  void UnPackTo(ApplicationDataT *_o, const flatbuffers::resolver_function_t *_resolver = nullptr) const;
+  static flatbuffers::Offset<ApplicationData> Pack(flatbuffers::FlatBufferBuilder &_fbb, const ApplicationDataT* _o, const flatbuffers::rehasher_function_t *_rehasher = nullptr);
+};
+
+struct ApplicationDataBuilder {
+  flatbuffers::FlatBufferBuilder &fbb_;
+  flatbuffers::uoffset_t start_;
+  void add_vectors(flatbuffers::Offset<flatbuffers::Vector<const Geometry::Vector3D *>> vectors) {
+    fbb_.AddOffset(ApplicationData::VT_VECTORS, vectors);
+  }
+  explicit ApplicationDataBuilder(flatbuffers::FlatBufferBuilder &_fbb)
+        : fbb_(_fbb) {
+    start_ = fbb_.StartTable();
+  }
+  ApplicationDataBuilder &operator=(const ApplicationDataBuilder &);
+  flatbuffers::Offset<ApplicationData> Finish() {
+    const auto end = fbb_.EndTable(start_);
+    auto o = flatbuffers::Offset<ApplicationData>(end);
+    return o;
+  }
+};
+
+inline flatbuffers::Offset<ApplicationData> CreateApplicationData(
+    flatbuffers::FlatBufferBuilder &_fbb,
+    flatbuffers::Offset<flatbuffers::Vector<const Geometry::Vector3D *>> vectors = 0) {
+  ApplicationDataBuilder builder_(_fbb);
+  builder_.add_vectors(vectors);
+  return builder_.Finish();
+}
+
+inline flatbuffers::Offset<ApplicationData> CreateApplicationDataDirect(
+    flatbuffers::FlatBufferBuilder &_fbb,
+    const std::vector<Geometry::Vector3D> *vectors = nullptr) {
+  auto vectors__ = vectors ? _fbb.CreateVectorOfStructs<Geometry::Vector3D>(*vectors) : 0;
+  return Geometry::CreateApplicationData(
+      _fbb,
+      vectors__);
+}
+
+flatbuffers::Offset<ApplicationData> CreateApplicationData(flatbuffers::FlatBufferBuilder &_fbb, const ApplicationDataT *_o, const flatbuffers::rehasher_function_t *_rehasher = nullptr);
+
+inline ApplicationDataT *ApplicationData::UnPack(const flatbuffers::resolver_function_t *_resolver) const {
+  auto _o = new ApplicationDataT();
+  UnPackTo(_o, _resolver);
+  return _o;
+}
+
+inline void ApplicationData::UnPackTo(ApplicationDataT *_o, const flatbuffers::resolver_function_t *_resolver) const {
+  (void)_o;
+  (void)_resolver;
+  { auto _e = vectors(); if (_e) { _o->vectors.resize(_e->size()); for (flatbuffers::uoffset_t _i = 0; _i < _e->size(); _i++) { _o->vectors[_i] = flatbuffers::UnPack(*_e->Get(_i)); } } };
+}
+
+inline flatbuffers::Offset<ApplicationData> ApplicationData::Pack(flatbuffers::FlatBufferBuilder &_fbb, const ApplicationDataT* _o, const flatbuffers::rehasher_function_t *_rehasher) {
+  return CreateApplicationData(_fbb, _o, _rehasher);
+}
+
+inline flatbuffers::Offset<ApplicationData> CreateApplicationData(flatbuffers::FlatBufferBuilder &_fbb, const ApplicationDataT *_o, const flatbuffers::rehasher_function_t *_rehasher) {
+  (void)_rehasher;
+  (void)_o;
+  struct _VectorArgs { flatbuffers::FlatBufferBuilder *__fbb; const ApplicationDataT* __o; const flatbuffers::rehasher_function_t *__rehasher; } _va = { &_fbb, _o, _rehasher}; (void)_va;
+  auto _vectors = _o->vectors.size() ? _fbb.CreateVectorOfNativeStructs<Geometry::Vector3D>(_o->vectors) : 0;
+  return Geometry::CreateApplicationData(
+      _fbb,
+      _vectors);
+}
+
+inline const flatbuffers::TypeTable *Vector3DTypeTable() {
+  static const flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 },
+    { flatbuffers::ET_FLOAT, 0, -1 }
+  };
+  static const int64_t values[] = { 0, 4, 8, 12 };
+  static const char * const names[] = {
+    "x",
+    "y",
+    "z"
+  };
+  static const flatbuffers::TypeTable tt = {
+    flatbuffers::ST_STRUCT, 3, type_codes, nullptr, values, names
+  };
+  return &tt;
+}
+
+inline const flatbuffers::TypeTable *ApplicationDataTypeTable() {
+  static const flatbuffers::TypeCode type_codes[] = {
+    { flatbuffers::ET_SEQUENCE, 1, 0 }
+  };
+  static const flatbuffers::TypeFunction type_refs[] = {
+    Geometry::Vector3DTypeTable
+  };
+  static const char * const names[] = {
+    "vectors"
+  };
+  static const flatbuffers::TypeTable tt = {
+    flatbuffers::ST_TABLE, 1, type_codes, type_refs, nullptr, names
+  };
+  return &tt;
+}
+
+inline const Geometry::ApplicationData *GetApplicationData(const void *buf) {
+  return flatbuffers::GetRoot<Geometry::ApplicationData>(buf);
+}
+
+inline const Geometry::ApplicationData *GetSizePrefixedApplicationData(const void *buf) {
+  return flatbuffers::GetSizePrefixedRoot<Geometry::ApplicationData>(buf);
+}
+
+inline ApplicationData *GetMutableApplicationData(void *buf) {
+  return flatbuffers::GetMutableRoot<ApplicationData>(buf);
+}
+
+inline bool VerifyApplicationDataBuffer(
+    flatbuffers::Verifier &verifier) {
+  return verifier.VerifyBuffer<Geometry::ApplicationData>(nullptr);
+}
+
+inline bool VerifySizePrefixedApplicationDataBuffer(
+    flatbuffers::Verifier &verifier) {
+  return verifier.VerifySizePrefixedBuffer<Geometry::ApplicationData>(nullptr);
+}
+
+inline void FinishApplicationDataBuffer(
+    flatbuffers::FlatBufferBuilder &fbb,
+    flatbuffers::Offset<Geometry::ApplicationData> root) {
+  fbb.Finish(root);
+}
+
+inline void FinishSizePrefixedApplicationDataBuffer(
+    flatbuffers::FlatBufferBuilder &fbb,
+    flatbuffers::Offset<Geometry::ApplicationData> root) {
+  fbb.FinishSizePrefixed(root);
+}
+
+inline flatbuffers::unique_ptr<Geometry::ApplicationDataT> UnPackApplicationData(
+    const void *buf,
+    const flatbuffers::resolver_function_t *res = nullptr) {
+  return flatbuffers::unique_ptr<Geometry::ApplicationDataT>(GetApplicationData(buf)->UnPack(res));
+}
+
+inline flatbuffers::unique_ptr<Geometry::ApplicationDataT> UnPackSizePrefixedApplicationData(
+    const void *buf,
+    const flatbuffers::resolver_function_t *res = nullptr) {
+  return flatbuffers::unique_ptr<Geometry::ApplicationDataT>(GetSizePrefixedApplicationData(buf)->UnPack(res));
+}
+
+}  // namespace Geometry
+
+#endif  // FLATBUFFERS_GENERATED_NATIVETYPETEST_GEOMETRY_H_

tests/native_type_test_impl.cpp

@@ -0,0 +1,13 @@
+#include "native_type_test_impl.h"
+#include "native_type_test_generated.h"
+
+namespace flatbuffers {
+  Geometry::Vector3D Pack(const Native::Vector3D &obj) {
+    return Geometry::Vector3D(obj.x, obj.y, obj.z);
+  }
+
+  const Native::Vector3D UnPack(const Geometry::Vector3D &obj) {
+    return Native::Vector3D(obj.x(), obj.y(), obj.z());
+  }
+}
+

tests/native_type_test_impl.h

@@ -0,0 +1,24 @@
+#ifndef NATIVE_TYPE_TEST_IMPL_H
+#define NATIVE_TYPE_TEST_IMPL_H
+
+namespace Native {
+  struct Vector3D {
+    float x;
+    float y;
+    float z;
+
+    Vector3D() { x = 0; y = 0; z = 0; };
+    Vector3D(float x, float y, float z) { this->x = x; this->y = y; this->z = z; }
+  };
+}
+
+namespace Geometry { 
+  struct Vector3D;
+}
+
+namespace flatbuffers {
+  Geometry::Vector3D Pack(const Native::Vector3D &obj);
+  const Native::Vector3D UnPack(const Geometry::Vector3D &obj);
+}
+
+#endif // VECTOR3D_PACK_H

tests/test.cpp

@@ -35,12 +35,15 @@
 #include "union_vector/union_vector_generated.h"
 #include "monster_extra_generated.h"
 #if !defined(_MSC_VER) || _MSC_VER >= 1700
-#  include "arrays_test_generated.h"
+#include "arrays_test_generated.h"
 #endif
+
+#include "native_type_test_generated.h"
 #include "test_assert.h"
 
 #include "flatbuffers/flexbuffers.h"
 
+
 // clang-format off
 // Check that char* and uint8_t* are interoperable types.
 // The reinterpret_cast<> between the pointers are used to simplify data loading.
@@ -2867,6 +2870,29 @@ void FixedLengthArrayTest() {
 #endif
 }
 
+void NativeTypeTest() {
+  const int N = 3;
+
+  Geometry::ApplicationDataT src_data;
+  src_data.vectors.reserve(N);
+
+  for (int i = 0; i < N; ++i) {
+    src_data.vectors.push_back (Native::Vector3D(10 * i + 0.1f, 10 * i + 0.2f, 10 * i + 0.3f));
+  }
+
+  flatbuffers::FlatBufferBuilder fbb;
+  fbb.Finish(Geometry::ApplicationData::Pack(fbb, &src_data));
+
+  auto dstDataT =  Geometry::UnPackApplicationData(fbb.GetBufferPointer());
+
+  for (int i = 0; i < N; ++i) {
+    Native::Vector3D& v = dstDataT->vectors[i];
+    TEST_EQ(v.x, 10 * i + 0.1f);
+    TEST_EQ(v.y, 10 * i + 0.2f);
+    TEST_EQ(v.z, 10 * i + 0.3f);
+  }
+}
+
 void FixedLengthArrayJsonTest(bool binary) {  
   // VS10 does not support typed enums, exclude from tests
 #if !defined(_MSC_VER) || _MSC_VER >= 1700
@@ -3011,6 +3037,7 @@ int FlatBufferTests() {
   InvalidFloatTest();
   TestMonsterExtraFloats();
   FixedLengthArrayTest();
+  NativeTypeTest();
   return 0;
 }