Here the benefit is especially clear -- as Containers::Pair is trivially
copyable with trivial types, all growable arrays can make use of
std::realloc() while with the STL variant a silly constructor, copy
constructor, destructor had to be used.
Additionally, we no longer need to take explicit care of libc++ and MSVC
STL where returning a std::pair<bool, Containers::String> as
return {{}, Containers::String{..., <deleter>}};
would caused an unnecessary copy instead of a move, losing the custom
deleter in the process. Yay!
There's a <Corrade/Containers/PairStl.h> include for backwards
compatibility purposes, but obviously it would only work for the return
type of validate*() and cases where an initializer list was passed to a
list-of-pairs-taking functions, and not a concretely typed ArrayView.
Those functions were though mostly the linker API which isn't
implemented by any plugin yet, so it shouldn't be *that* breaking to
users. Neverteless, I'm trying to do this breaking change rather sooner
than later to prevent pain further down the road when the Vulkan APIs
and SPIR-V pipeline gets widely used.
Consistently with changes done to Utility::Path, this enforces proper
error handling on user side. Originally I didn't want to do this and
instead wanted to have a special Array instance devoted for an error
state, but that still would allow the error state be errorneously
treated as a successful but empty array.
It's more useful if the Error class is directly referenced than saying
just "error output" -- so people can grab it, redirect it, etc. Also
drop the useless "does what it is expected to do on success" sentences
that add no value whatsoever.
I wanted to avoid including extra stuff with the Manager.hpp split, but
this would make it even worse than having Array and String included
unconditionally. Fortunately it's enough to simply not even have the
declaration.
There will be Flag::FlipY for images at some point, enabled by default
for compatibility with existing GL code, and so it makes sense to start
discouraging setFlags() as early as possible to avoid people resetting
the default by accident.
Also update the imageconverter, sceneconverter and shaderconverter utils
to use these instead of setFlags().
Vladimír Vondruš