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.
Somehow. Heh. This causes a non-deprecated build on MSVC to break due to
a similar reason as in 54394e2c2f. And,
similarly to 3717043ae2, *again*
discovered while building bindings.
It limits the support for CMake 3.12+, but it's much less verbose and I
don't expect people to use ancient CMake versions with IDEs like Xcode
or VS anyway, so this should be fine.
Except for file callbacks, for these I have another change planned for
zero-copy import and it would be unwise to break stuff twice, providing
two sets of backwards compatibility wrappers. The image / scene
converter plugins went through a similar change earlier already and the
shader converters were made sane since the very beginning. OTOH audio
importers and text stuff are scheduled for merging with Trade or a
larger rework anyway, so I didn't see any point in updating those.
It's mostly a trivial change, except that returned String instances are
now also checked for non-default deleters same as Arrays because yes,
wow such flexibility compared to STL strings. Same was done for
ShaderTools::AbstractConverter already anyway, so nothing unheard-of
either.
The importer plugin interface version is bumped as this likely breaks
ABI in a nasty way that would lead to crashes.
Like in Trade, the unatomic exists() + read() pair (and silent failures
if the file exists but can't be read) was replaced with just
Path::read() that now returns an Optional. Besides that, not much worth
mentioning.
Since the plugin implementations rely on the base plugin interfaces for
file handling, this affected only the tests. Also took this as an
opportunity to use the new TestSuite::Compare::StringHasPrefix etc. in
various places.
It doesn't make the test any simpler, easier to understand or less
error prone, on the contrary. And it would stop testing the intended
code path once file callbacks are implemented inside the importer.
These checks covered the case when the magnum-plugins repository wasn't
installed, but didn't cover the case when it was installed but the
plugins were built against an outdated interface, had ABI issues, or
didn't load at all for various other reasons.
And prefere to use it onver OpenEXR in most AnyImage{Converter,Importer}
tests, unless the test really needs something that only OpenEXR has
(such as the verbose output for threads or configuration that needs to
be set on both export and import to make the import succeed).
With the previous commits, existing plugin implementations built and ran
against the new code, however it introduced several ABI breaks meaning
that existing plugin binaries would crash. This forces them to be
recompiled to match the new version string.
Using openMemory() instead of openData() allows the implementation to
assume the data will stay in scope for as long as needed, which can
prevent unnecessary copies in some plugin implementations.
It warranted a new flag, DataFlag::ExternallyOwned, to describe this
kind of memory. I couldn't reuse Owned as that's used for allocations
owned by the instance, which is too little for certain future use cases.
For example returning *Data instances referencing an Owned memory would
mean the user has to assume the memory is gone when the importer
instance is gone, and that's generally not true for memory passed to
openMemory().
Originally I thought I would do this later, but then realized the
existing plugin implementations would need to get all updated again to
be aware of the new flag, with some being forgotten, and it's just
easier to do the whole thing in a single step.
Vladimír Vondruš