memory/shared: add dynamicPointerCast

[vaxerski]

Adds a dynamic cast equivalent for our shared pointers. Tests pass, I hope nothing implodes xD

cc @PaideiaDilemma @gulafaran can yall check I didnt mess something up

[gulafaran]

it imploded.

#0  Hyprutils::Memory::Impl_::impl_base::dataNonNull (this=0x556879867800) at /usr/include/hyprutils/memory/ImplBase.hpp:101
101	                    return m_control->_data && m_object != nullptr;
[Current thread is 1 (Thread 0x7f4c740f0240 (LWP 8228))]
(gdb) bt
#0  Hyprutils::Memory::Impl_::impl_base::dataNonNull (this=0x556879867800) at /usr/include/hyprutils/memory/ImplBase.hpp:101
#1  0x00005568413b256f in Hyprutils::Memory::CSharedPointer<Aquamarine::CBackend>::operator bool (this=0x5568797af218)
    at /usr/include/hyprutils/memory/SharedPtr.hpp:109
#2  0x000055684137e69e in CCompositor::initServer (this=0x5568797af1f0, socketName="", socketFd=-1)
    at /home/tom/dev/Hyprland/src/Compositor.cpp:342
#3  0x00005568416241d9 in main (argc=1, argv=0x7ffcc84100c8) at /home/tom/dev/Hyprland/src/main.cpp:192

/usr/include/hyprutils/memory/ImplBase.hpp:101:39: runtime error: member access within misaligned address 0x000300000002 for type 'struct SControl', which requires 8 byte alignment
0x000300000002: note: pointer points here
<memory cannot be printed>
    #0 0x55e21b7be48a in Hyprutils::Memory::Impl_::impl_base::dataNonNull() /usr/include/hyprutils/memory/ImplBase.hpp:101
    #1 0x55e21b7e503a in Hyprutils::Memory::CSharedPointer<Aquamarine::CBackend>::operator bool() const /usr/include/hyprutils/memory/SharedPtr.hpp:109
    #2 0x55e21b74e777 in CCompositor::initServer(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, int) /home/tom/dev/Hyprland/src/Compositor.cpp:342
    #3 0x55e21bfab3f3 in main /home/tom/dev/Hyprland/src/main.cpp:192
    #4 0x7f7adf42b045  (/usr/lib64/libc.so.6+0x2b045)
    #5 0x7f7adf42b0f5 in __libc_start_main (/usr/lib64/libc.so.6+0x2b0f5)
    #6 0x55e21b748820 in _start (/home/tom/dev/Hyprland/build/Desktop-Debug/Hyprland+0x48be820)
    ```

[vaxerski]

try now

[gulafaran]

try now

nope

[ERR] [AQ] Failed to open a session
[ERR] [AQ] DRM Backend failed
/usr/include/hyprutils/memory/ImplBase.hpp:103:39: runtime error: member access within misaligned address 0x000300000002 for type 'struct SControl', which requires 8 byte alignment
0x000300000002: note: pointer points here
<memory cannot be printed>
    #0 0x55b4558f4486 in Hyprutils::Memory::Impl_::impl_base::dataNonNull() /usr/include/hyprutils/memory/ImplBase.hpp:103
    #1 0x55b45591b036 in Hyprutils::Memory::CSharedPointer<Aquamarine::CBackend>::operator bool() const /usr/include/hyprutils/memory/SharedPtr.hpp:109
    #2 0x55b455884777 in CCompositor::initServer(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, int) /home/tom/dev/Hyprland/src/Compositor.cpp:342
    #3 0x55b4560e13ef in main /home/tom/dev/Hyprland/src/main.cpp:192
    #4 0x7fd337a2b045  (/usr/lib64/libc.so.6+0x2b045)
    #5 0x7fd337a2b0f5 in __libc_start_main (/usr/lib64/libc.so.6+0x2b0f5)
    #6 0x55b45587e820 in _start (/home/tom/dev/Hyprland/build/Desktop-Debug/Hyprland+0x48be820)

Segmentation fault         (core dumped) ./Hyprland

Program terminated with signal SIGSEGV, Segmentation fault.
b#0  0x000055b4558f44a9 in Hyprutils::Memory::Impl_::impl_base::dataNonNull (this=0x55b477979990)
    at /usr/include/hyprutils/memory/ImplBase.hpp:103
103	                    return m_control->_data && m_object != nullptr;
[Current thread is 1 (Thread 0x7fd331eec240 (LWP 15070))]
(gdb) bt
#0  0x000055b4558f44a9 in Hyprutils::Memory::Impl_::impl_base::dataNonNull (this=0x55b477979990)
    at /usr/include/hyprutils/memory/ImplBase.hpp:103
#1  0x000055b45591b037 in Hyprutils::Memory::CSharedPointer<Aquamarine::CBackend>::operator bool (this=0x55b4778c1218)
    at /usr/include/hyprutils/memory/SharedPtr.hpp:109
#2  0x000055b455884778 in CCompositor::initServer (this=0x55b4778c11f0, socketName="", socketFd=-1)
    at /home/tom/dev/Hyprland/src/Compositor.cpp:342
#3  0x000055b4560e13f0 in main (argc=1, argv=0x7ffea8956708) at /home/tom/dev/Hyprland/src/main.cpp:192
```

[vaxerski]

you didnt rebuild aq xd

[gulafaran]

you didnt rebuild aq xd

yeah ABI matters it seems ;) disregard the above self inflicted implosions. nested runs, il proceed with a complete rebuild and check live too.

[vaxerski]

yeah and this leaks gotta fix

[PaideiaDilemma]

I am a bit confused.
Dynamic casts don't change a pointer value. they just make the pointer be interpreted as T instead of U right??
If that is the case, we don't need to construct a different impl when we do a dynamic cast. We just need to have SharedPointer be of type T instead of U.
Since we have DeleterFN now, it will even call the correct deleter, because that remains to be the deleter of U and not T.
Am I missing something?

[PaideiaDilemma]

Ok as a cpp noop i didnt know that multiple inheritance can actually change the pointer. I now understand

[vaxerski]

cpp moment

[vaxerski]

Alternative approach. Seems to work. Please test :)

[PaideiaDilemma]

It does seem to work fine.

But idk if it is a good idea to have this pointer in SP.
Idea: maybe somthing like a CDynamicCastWrapper that can wrap (A)SP and (A)WP and does the dynamic cast when you access the pointer?

If we want this: #93, it would be nice if that would also work for WP's.
That way we could have a UP somewhere owning the reference and do dynamic casts on the WP.