UI Code Quality: Ghost C++ Coding-Style #74430

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opened 2020-03-04 13:14:07 +01:00 by Julian Eisel · 1 comment
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UI Code Quality: Ghost C++ Coding-Style

NOTE: This is a proposal, not an agreed on plan.

Ghost probably wouldn't benefit too greatly from modern C++ usage, but there are a few features that might be handy. Changes proposed here should move us closer to following the C++ guidelines: http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines.

We should not spend big amounts of time on this, especially since there are no major benefits to expect. It is however a nice, isolated place to introduce more modern C++ features to the UI code, for experimenting with it and to get developers familiar with the rather different coding style.
If this works well for us and we add more C++ to our UI code, we should follow the same rules.

  • Switch to blender::ghost namespace (see style guide ).
  • Use blender:: containers rather than std:: ones (see style guide ).
  • override, virtual and final keywords: Explicit usage of these terms in class hierarchies may prevent some errors. Especially override and final since they lead to a compile error on function signature mismatch (C.128).
  • std::unique_ptr: It's considered good practise to use smart pointers (esp. std::unique_ptr) to manage lifetimes of C++ objects. They make object ownership explicit and enforce static sanity checks. ([R.1]], http:*isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rr-newdelete , [http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rr-owner | R.20). We may want to add our own make_unique() too, which is only available in C++17.
  • default and delete constructors and destructors: Using these may help catch some errors at compile time, make classes more compatible with std containers and allows optimizations for trivial operation (e.g. a = default copy constructor makes a type "trivially copyable", which some containers and compilers optimize for) ([C.43]], http:*isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-eqdefault , [http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-delete | C.81).
  • In-class initializer: Among other reasons, making good use of in-class initialization reduces likelyhood of uninitialized members ([C48]], [http:*isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-in-class-initializer | C.45).
  • Range-based for loops: Ghost uses std containers in a few places. C++11 range-based for loops make iterating them far less verbose (ES.71).
  • auto to avoid verbosity/redundancy: While there are good reasons to be sceptical about auto, there are few cases where they are definitely useful. For example in case of long type names (like std::vector<std::unique_ptr<SomeType>>::const_iterator). (ES.11)
  • using over typedef: The using syntax to create aliases is often considered more readable. (T.43).
  • nullptr: More on the esthetical side of things (although may avoid some nasty surprises!), but we should use standard nullptr instead of NULL. We can avoid including stddef.h everywhere then. (ES.47)

Other, similar improvements are possible. These are just a few examples of low hanging fruits.

## UI Code Quality: Ghost C++ Coding-Style NOTE: This is a proposal, not an agreed on plan. Ghost probably wouldn't benefit too greatly from modern C++ usage, but there are a few features that might be handy. Changes proposed here should move us closer to following the C++ guidelines: http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines. We should not spend big amounts of time on this, especially since there are no major benefits to expect. It is however a nice, isolated place to introduce more modern C++ features to the UI code, for experimenting with it and to get developers familiar with the rather different coding style. If this works well for us and we add more C++ to our UI code, we should follow the same rules. * Switch to `blender::ghost` namespace (see [style guide ](https://wiki.blender.org/wiki/Style_Guide/C_Cpp#C.2B.2B_Namespaces)). * Use `blender::` containers rather than `std::` ones (see [style guide ](https://wiki.blender.org/wiki/Style_Guide/C_Cpp#C.2B.2B_Containers)). * `override`, `virtual` and `final` keywords: Explicit usage of these terms in class hierarchies may prevent some errors. Especially `override` and `final` since they lead to a compile error on function signature mismatch ([C.128](http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rh-override)). * `std::unique_ptr`: It's considered good practise to use smart pointers (esp. `std::unique_ptr`) to manage lifetimes of C++ objects. They make object ownership explicit and enforce static sanity checks. ([R.1]], [[http:*isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rr-newdelete | R.11]], [[http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rr-owner | R.20](http:*isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rr-raii)). We may want to add our own `make_unique()` too, which is only available in C++17. * `default` and `delete` constructors and destructors: Using these may help catch some errors at compile time, make classes more compatible with `std` containers and allows optimizations for trivial operation (e.g. a `= default` copy constructor makes a type "trivially copyable", which some containers and compilers optimize for) ([C.43]], [[http:*isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-eqdefault | C.80]], [[http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-delete | C.81](http:*isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-default0)). * In-class initializer: Among other reasons, making good use of in-class initialization reduces likelyhood of uninitialized members ([C48]], [[http:*isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-in-class-initializer | C.45](http:*isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-in-class-initializer)). * Range-based for loops: Ghost uses `std` containers in a few places. C++11 range-based for loops make iterating them far less verbose ([ES.71](http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Res-for-range)). * `auto` to avoid verbosity/redundancy: While there are good reasons to be sceptical about `auto`, there are few cases where they are definitely useful. For example in case of long type names (like `std::vector<std::unique_ptr<SomeType>>::const_iterator`). ([ES.11](http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Res-auto)) * `using` over `typedef`: The `using` syntax to create aliases is often considered more readable. ([T.43](http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rt-using)). * `nullptr`: More on the esthetical side of things (although may avoid some nasty surprises!), but we should use standard `nullptr` instead of `NULL`. We can avoid including `stddef.h` everywhere then. ([ES.47](http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Res-nullptr)) Other, similar improvements are possible. These are just a few examples of low hanging fruits.
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Added subscriber: @JulianEisel

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Philipp Oeser removed the
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User Interface
label 2023-02-10 09:24:46 +01:00
Iliya Katushenock removed the
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label 2024-02-06 12:09:09 +01:00
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