Casting pointers from one type to another does change the
value of the pointer in some cases. Therefore, casting a span
that contains pointers of one type to a span that contains
pointers of another type, is not generally safe. In practice, this
issue mainly comes up when dealing with classes that have a
vtable.
There are some special cases that are still allowed. For example,
adding const to the pointer does not change the address.
Also, casting to a void pointer is fine.
In cases where implicit conversion is disabled, but one is sure
that the cast is valid, an explicit call of `span.cast<NewType>()`
can be used.
Using C++ exceptions in Blender is difficult, due to the large
number of C functions in the call stack. However, C++ data
structures in blenlib should at least try to be exception safe,
so that they can be used if someone wants to use exceptions
in some isolated area.
This patch improves the exception safety of the Vector, Array
and Stack data structure. This is mainly achieved by reordering
some lines and doing some explicit exception handling.
I don't expect performance of common operations to be affected
by this change.
The three containers are supposed to provide at least the
basic exception guarantee for most methods (except for e.g.
`*_unchecked` methods). So, resources should not leak when
the contained type throws an exception.
I also added new unit tests that test the exception handling
in various cases.
This replaces header include guards with `#pragma once`.
A couple of include guards are not removed yet (e.g. `__RNA_TYPES_H__`),
because they are used in other places.
This patch has been generated by P1561 followed by `make format`.
Differential Revision: https://developer.blender.org/D8466
Those are useful when you have to create containers with static
storage duration. If those would use Blender's guarded allocator,
it would report memory leaks, that are not actually leaks.
This updates the usage of integer types in code I wrote according to our new style guides.
Major changes:
* Use signed instead of unsigned integers in many places.
* C++ containers in blenlib use `int64_t` for size and indices now (instead of `uint`).
* Hash values for C++ containers are 64 bit wide now (instead of 32 bit).
I do hope that I broke no builds, but it is quite likely that some compiler reports
slightly different errors. Please let me know when there are any errors. If the fix
is small, feel free to commit it yourself.
I compiled successfully on linux with gcc and on windows.
The move constructor of `mpq_class` from GMP currently
allocates when it is moved. So, it cannot be noexcept.
Since we want to use this type, this static assert cannot
stay there.
This allows us to avoid many calls to `as_span()` methods. I will
remove those in the next commit. Furthermore, constructors
of Vector and Array can convert from one type to another now.
I tested these changes on Linux with gcc and on Windows.
Even if we do not use exception in many places in Blender, our core C++ library
should become exception safe. Otherwise, we don't even have the option
to work with exceptions if we decide to do so.
The main focus here was to improve the docs significantly. Furthermore,
I reimplemented `Set`, `Map` and `VectorSet`. They are now (usually)
faster, simpler and more customizable. I also rewrote `Stack` to make
it more efficient by avoiding unnecessary copies.
Thanks to everyone who helped with constructive feedback.
Approved by brecht and sybren.
Differential Revision: https://developer.blender.org/D7931
