Apologies for the enormous commit, but I don't see a way to split this
up nicely. In the vast majority of cases it's a simple change. A few
extra places can use TRY instead of manual error checking though. :^)
Rather than casting the FixedPoint to double, format the FixedPoint
directly. This avoids using floating point instruction, which in
turn enables this to be used even in the kernel.
This makes the following code behave as expected:
Variant<int, String> x { some_string() };
x.visit(
[](String const&) {}, // Expectation is for this to be called
[](auto&) {});
Except for tangential accessors such as data(), there is no more feature
of FixedArray that is untested after this large expansion of its test
cases. These tests, with the help of the new NoAllocationGuard, also
test the allocation contract that was fixated in the last commit.
Hopefully this builds confidence in future Kernel uses of FixedArray
as well as its establishment in the real-time parts of the audio
subsystem. I'm excited :^)
FixedArray always *almost* had the following allocation guarantees:
There is (possibly) one allocation in the constructor and one (or more)
deallocation(s) in the destructor. No other operation allocates or
deallocates. With this removal of the public clear() method, which
nobody except the test used anyways, those guarantees are now completely
true and furthermore fixated with an explanatory comment.
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.
Currently, we define a CaseInsensitiveStringTraits structure for String.
Using this structure for StringView involves allocating a String from
that view, and a second string to convert that intermediate string to
lowercase.
This defines CaseInsensitiveStringViewTraits (and the underlying helper
case_insensitive_string_hash) to avoid allocations.
FixedArray now doesn't expose any infallible constructors anymore.
Rather, it exposes fallible methods. Therefore, it can be used for
OOM-safe code.
This commit also converts the rest of the system to use the new API.
However, as an example, VMObject can't take advantage of this yet,
as we would have to endow VMObject with a fallible static
construction method, which would require a very fundamental change
to VMObject's whole inheritance hierarchy.
The previous implementation had some pretty short cycles and two fixed
points (1711463637 and 2389024350). If two keys hashed to one of these
values insertions and lookups would loop forever.
This version is based on a standard xorshift PRNG with period 2**32-1.
The all-zero state is usually forbidden, so we insert it into the cycle
at an arbitrary location.
As it was, negative predicate test for remove_all_matching was
run on empty hash map, and could not remove anything, so test always
returned true. By duplicating it in state where hash maps contains
elements, we make sure that negative predicate has something to
do nothing on.
This is a raffinement of 49cbd4dcca.
Previously, the container was scanned to compute the size in the unhappy
path. Now, using `all_of` happy and unhappy path should be fast.
The goal of this file is to enable C++ overloaded functions for
standard builtin functions that we use. It contains fallback
implementations for systems that do not have the builtins available.
This unbreaks the /var/run/utmp system which starts out as an empty
string, and is then turned into an object by the first update.
This isn't necessarily the best way for this to work, but it's how
it used to work, so this just fixes the regression for now.
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.
Also add slightly richer parse errors now that we can include a string
literal with returned errors.
This will allow us to use TRY() when working with JSON data.
When I added this code in 1472f6d, I forgot to add tests for it. That's
why I didn't realize that the values were appended to the wrong
FormatBuilder object, so an empty string was returned instead of the
expected "nan"/"inf". This made debugging some FPU issues with the
ScummVM port significantly more difficult.
In the long-term, we should probably have a way to signal decoding
failure. For now, it should suffice to at least not crash. This is
particularly relevant because apparently this can be triggered while
parsing a PEM certificate, which happens during every TLS connection.
Found by OSS Fuzz
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=38979
DisjointChunks<T> provides a nice interface over multiple sequential
Vector<T>'s, allowing the user to iterate over/index into/slice from
said buffers as if they were a single contiguous buffer.
To work with views on such objects, DisjointSpans<T> is provided, which
has the same behaviour but does not own the underlying objects.
This removes the awkward String::replace API which was the only String
API which mutated the String and replaces it with a new immutable
version that returns a new String with the replacements applied. This
also fixes a couple of UAFs that were caused by the use of this API.
As an optimization an equivalent StringView::replace API was also added
to remove an unnecessary String allocations in the format of:
`String { view }.replace(...);`
This avoids a value copy when calling value() or value_or() on a
temporary Optional. This is very common when using the HashMap::get()
API like this:
auto value = hash_map.get(key).value_or(fallback_value);
