Before this change, the global FlyString table looked like this:
HashMap<StringView, Detail::StringBase>
After this change, we have:
HashTable<Detail::StringData const*, FlyStringTableHashTraits>
The custom hash traits are used to extract the stored hash from
StringData which avoids having to rehash the StringView repeatedly like
we did before.
This necessitated a handful of smaller changes to make it work.
Let's add FlyString::from_deprecated_fly_string() so we can use it
instead of FlyString::from_utf8(). This will make it easier to detect
potential unncessary allocations as we transfer to FlyString.
This implements a FlyString that will de-duplicate String instances. The
FlyString will store the raw encoded data of the String instance: If the
String is a short string, FlyString holds the String::ShortString bytes;
otherwise FlyString holds a pointer to the Detail::StringData.
FlyString itself does not know about String's storage or how to refcount
its Detail::StringData. It defers to String to implement these details.
DeprecatedFlyString relies heavily on DeprecatedString's StringImpl, so
let's rename it to A) match the name of DeprecatedString, B) write a new
FlyString class that is tied to String.
This will make it easier to support both string types at the same time
while we convert code, and tracking down remaining uses.
One big exception is Value::to_string() in LibJS, where the name is
dictated by the ToString AO.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
These are guarded with #ifndef KERNEL, since doubles (and floats) are
not allowed in KERNEL mode.
In StringUtils there is convert_to_floating_point which does have a
template parameter incase you have a templated type.
If we're constructing a FlyString from a StringView, and we already
have a matching StringImpl in the table, use HashTable::find() to
locate the existing string without creating a temporary String.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
This is basically just for consistency, it's quite strange to see
multiple AK container types next to each other, some with and some
without the namespace prefix - we're 'using AK::Foo;' a lot and should
leverage that. :^)
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
MemoryManager cannot use the Singleton class because
MemoryManager::initialize is called before the global constructors
are run. That caused the Singleton to be re-initialized, causing
it to create another MemoryManager instance.
Fixes#3226
This was showing up in Browser profiles, which is silly, so write a new
version that doesn't create a temporary String object.
There are a whole bunch of these and long-term it would be nice to find
a way to share all the very similar logic instead of duplicating it.
Get rid of the weird old signature:
- int StringType::to_int(bool& ok) const
And replace it with sensible new signature:
- Optional<int> StringType::to_int() const
FlyString is a flyweight string class that wraps a RefPtr<StringImpl>
known to be unique among the set of FlyStrings. The class is very
unoptimized at the moment.
When to use FlyString:
- When you want O(1) string comparison
- When you want to deduplicate a lot of identical strings
When not to use FlyString:
- For strings that don't need either of the above features
- For strings that are likely to be unique
