flatbuffers/tests/cpp17/test_cpp17.cpp

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/*
* Copyright 2014 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// This is a sandbox for modeling C++17 code generator.
// C++17 code generator: "flatc --cpp_std c++17".
// Warning:
// This is an experimental feature and could change at any time.
#include "flatbuffers/flatbuffers.h"
#include "flatbuffers/flexbuffers.h"
#include "flatbuffers/idl.h"
#include "flatbuffers/minireflect.h"
#include "flatbuffers/registry.h"
#include "flatbuffers/util.h"
#include "test_assert.h"
// Embed generated code into an isolated namespace.
namespace cpp17 {
#include "generated_cpp17/monster_test_generated.h"
} // namespace cpp17
namespace cpp11 {
#include "../monster_test_generated.h"
} // namespace cpp11
[C++17] Add Traits class for Tables and Factory function within it. (#5678) * Include flattests_cpp17 in unit tests when C++17 build is enabled. * [C++17] Generate generic table factory function. 1. For each table, generate a convenient free-standing factory function that allows creating the table in a generic way by specifying only the type. This is the first change in a series of changes to make Flatbuffers generated C++ code more friendly to code bases that make use of C++ template metaprogramming techniques to manage the serialization process. Example: Before :( // The name of the Flatbuffers type (and namespace) must // be hard-coded when writing the factory function. auto monster = MyGame::Example::CreateMonster(fbb, ...); After :) using type_to_create = MyGame::Example::Monster; // No namespace needed on CreateByTagType. auto monster = CreateByTagType((type_to_create*)nullptr, fbb, ...); This feature requires building with C++14 or greater, and thus it is guarded behind --cpp-std >= c++17 in the flatbuffers C++ generator. 2. Fix a CMake bug to include C++17 unit tests in test suite. * [C++17] Replace standalone variadic factory function with type_traits. Add a `type_traits` to each table class. This `type_traits` can be populated with various compile-time info about the table. Initially, we have the Create* function and type, but is extensible in the future. * Remove empty line and fix stale comments. * Rename type_traits to Traits and move fwd declaration. * Fix parameter evaluation order issue and use lambda for scope.
2020-01-02 18:12:14 +00:00
void CreateTableByTypeTest() {
flatbuffers::FlatBufferBuilder builder;
// We will create an object of this type using only the type.
using type_to_create_t = cpp17::MyGame::Example::Stat;
[&builder] {
auto id_str = builder.CreateString("my_id");
auto table = type_to_create_t::Traits::Create(builder, id_str, 42, 7);
// Be sure that the correct return type was inferred.
static_assert(
std::is_same_v<decltype(table), flatbuffers::Offset<type_to_create_t>>);
builder.Finish(table);
}();
// Access it.
auto stat =
flatbuffers::GetRoot<type_to_create_t>(builder.GetBufferPointer());
TEST_EQ_STR(stat->id()->c_str(), "my_id");
TEST_EQ(stat->val(), 42);
TEST_EQ(stat->count(), 7);
}
int FlatBufferCpp17Tests() {
[C++17] Add Traits class for Tables and Factory function within it. (#5678) * Include flattests_cpp17 in unit tests when C++17 build is enabled. * [C++17] Generate generic table factory function. 1. For each table, generate a convenient free-standing factory function that allows creating the table in a generic way by specifying only the type. This is the first change in a series of changes to make Flatbuffers generated C++ code more friendly to code bases that make use of C++ template metaprogramming techniques to manage the serialization process. Example: Before :( // The name of the Flatbuffers type (and namespace) must // be hard-coded when writing the factory function. auto monster = MyGame::Example::CreateMonster(fbb, ...); After :) using type_to_create = MyGame::Example::Monster; // No namespace needed on CreateByTagType. auto monster = CreateByTagType((type_to_create*)nullptr, fbb, ...); This feature requires building with C++14 or greater, and thus it is guarded behind --cpp-std >= c++17 in the flatbuffers C++ generator. 2. Fix a CMake bug to include C++17 unit tests in test suite. * [C++17] Replace standalone variadic factory function with type_traits. Add a `type_traits` to each table class. This `type_traits` can be populated with various compile-time info about the table. Initially, we have the Create* function and type, but is extensible in the future. * Remove empty line and fix stale comments. * Rename type_traits to Traits and move fwd declaration. * Fix parameter evaluation order issue and use lambda for scope.
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CreateTableByTypeTest();
return 0;
}
int main(int /*argc*/, const char * /*argv*/[]) {
InitTestEngine();
FlatBufferCpp17Tests();
if (!testing_fails) {
TEST_OUTPUT_LINE("C++17: ALL TESTS PASSED");
} else {
TEST_OUTPUT_LINE("C++17: %d FAILED TESTS", testing_fails);
}
return CloseTestEngine();
}