This file does not contain any architecture specific implementations,
so we can move it to the Kernel base directory. Also update the relevant
include paths.
`OwnPtrWithCustomDeleter` was a decorator which provided the ability
to add a custom deleter to `OwnPtr` by wrapping and taking the deleter
as a run-time argument to the constructor. This solution means that no
additional space is needed for the `OwnPtr` because it doesn't need to
store a pointer to the deleter, but comes at the cost of having an
extra type that stores a pointer for every instance.
This logic is moved directly into `OwnPtr` by adding a template
argument that is defaulted to the default deleter for the type. This
means that the type itself stores the pointer to the deleter instead
of every instance and adds some type safety by encoding the deleter in
the type itself instead of taking a run-time argument.
Note that this still keeps the old behaviour of putting things in std by
default on serenity so the tools can be happy, but if USING_AK_GLOBALLY
is unset, AK behaves like a good citizen and doesn't try to put things
in the ::std namespace.
std::nothrow_t and its friends get to stay because I'm being told that
compilers assume things about them and I can't yeet them into a
different namespace...for now.
Until now, our kernel has reimplemented a number of AK classes to
provide automatic internal locking:
- RefPtr
- NonnullRefPtr
- WeakPtr
- Weakable
This patch renames the Kernel classes so that they can coexist with
the original AK classes:
- RefPtr => LockRefPtr
- NonnullRefPtr => NonnullLockRefPtr
- WeakPtr => LockWeakPtr
- Weakable => LockWeakable
The goal here is to eventually get rid of the Lock* classes in favor of
using external locking.
Instead of having two separate implementations of AK::RefCounted, one
for userspace and one for kernelspace, there is now RefCounted and
AtomicRefCounted.
C++20 provides the `requires` clause which simplifies the ability to
limit overload resolution. Prefer it over `EnableIf`
With all uses of `EnableIf` being removed, also remove the
implementation so future devs are not tempted.
This matches the likes of the adopt_{own, ref}_if_nonnull family and
also frees up the name to allow us to eventually add OOM-fallible
versions of these functions.
This mechanism was unsafe to use in any multithreaded context, since
the hook function was invoked on a raw pointer *after* decrementing
the local ref count.
Since we don't use it for anything anymore, let's just get rid of it.
Look for remove_from_secondary_lists() and call it on the ref-counting
target if present *while the lock is held*.
This allows listed-ref-counted objects to be present in multiple lists
and still have synchronized removal on final unref.
When doing the last unref() on a listed-ref-counted object, we keep
the list locked while mutating the ref count. The destructor itself
is invoked after unlocking the list.
This was racy with weakable classes, since their weak pointer factory
still pointed to the object after we'd decided to destroy it. That
opened a small time window where someone could try to strong-ref a weak
pointer to an object after it was removed from the list, but just before
the destructor got invoked.
This patch closes the race window by explicitly revoking all weak
pointers while the list is locked.
This isn't a complete conversion to ErrorOr<void>, but a good chunk.
The end goal here is to propagate buffer allocation failures to the
caller, and allow the use of TRY() with formatting functions.
cert-dcl50-cpp: No variadic functions, suppressed in RefCounted and
ThreadSafeRefCounted for implementing the magic one_ref_left and
will_be_destroyed functions.
cert-dcl58-cpp: No opening ::std, suppressed in the places we put names
in ::std to aid tools (move, forward, nullptr_t, align_val_t, etc).
We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace!
This was a slightly tedious refactoring that took a long time, so it's
not unlikely that some bugs crept in.
Nevertheless, it does pass basic functionality testing, and it's just
real nice to finally see the same pattern in all contexts. :^)
The platform independent Processor.h file includes the shared processor
code and includes the specific platform header file.
All references to the Arch/x86/Processor.h file have been replaced with
a reference to Arch/Processor.h.
While I was working on LibWeb, I got a page fault at 0xe0e0e0e4.
This indicates a destroyed RefPtr if compiled with SANITIZE_PTRS
defined. However, the page fault handler didn't print out this
indication.
This makes the page fault handler print out a note if the faulting
address looks like a recently destroyed RefPtr, OwnPtr, NonnullRefPtr,
NonnullOwnPtr, ThreadSafeRefPtr or ThreadSafeNonnullRefPtr. It will
only do this if SANITIZE_PTRS is defined, as smart pointers don't get
scrubbed without it being defined.
Some time ago, automatic locking was added to the AK smart pointers to
paper over various race conditions in the kernel. Until we've actually
solved the issues in the kernel, we're stuck with the locking.
However, we don't need to punish single-threaded userspace programs with
the high cost of locking. This patch moves the thread-safe variants of
RefPtr, NonnullRefPtr, WeakPtr and RefCounted into Kernel/Library/.
TmpFS inodes rely on the call to Inode::one_ref_left() to unregister
themselves from the inode cache in TmpFS.
When moving various kernel classes to ListedRefCounted for safe unref()
while participating on lists, I forgot to make ListedRefCounted check
for (and call) one_ref_left() & will_be_destroyed() on the CRTP class.
This class implements the emerging "ref-counted object that participates
in a lock-protected list that requires safe removal on unref()" pattern
as a base class that can be inherited in place of RefCounted<T>.
