Commit Graph
2 Commits
Author SHA1 Message Date
David P. Sicilia d54af8cd43 [C++] Use strong enum type for vectors when scoped-enums is on. (#5750)
* [C++] Use strong enum type for vectors when scoped-enums is on.

These changes only apply when scoped-enums is on, and thus only
the C++17 tests show diffs.

This may break users who use 1) use scoped-enums and 2) use
vectors of enums.  However, it seems that this change should
have been made originally when scoped-enums were added.

Fixes #5285

* [C++] Put strong enum change also behind C++17 flag.

It actually only needs C++11 technically, but this is being done
to avoid breaking any existing users.

Tests were rerun, but produced no additional diffs, as expected.

* [C++] Forgot one location in which C++17 guard needs to go.

This commit produces no additional diffs in generated code.

* Use g_only_fixed_enums instead of scoped_enums.
2020-02-10 17:45:32 -08:00
David P. Sicilia a5d9d0f7d3 [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 10:12:14 -08:00