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AK: Remove String-from-StringView optimization

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We had an unusual optimization in AK::StringView where constructing
a StringView from a String would cause it to remember the internal
StringImpl pointer of the String.

This was used to make constructing a String from a StringView fast
and copy-free.

I tried removing this optimization and indeed we started seeing a
ton of allocation traffic. However, all of it was due to a silly
pattern where functions would take a StringView and then go on
to create a String from it.

I've gone through most of the code and updated those functions to
simply take a String directly instead, which now makes this
optimization unnecessary, and indeed a source of bloat instead.

So, let's get rid of it and make StringView a little smaller. :^)
This commit is contained in:
Andreas Kling 2021-04-17 01:18:39 +02:00
parent 94b247c5a9
commit 873da38d0e
4 changed files with 5 additions and 17 deletions
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10
AK/StringView.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -35,15 +35,13 @@
namespace AK {
StringView::StringView(const String& string)
: m_impl(string.impl())
, m_characters(string.characters())
: m_characters(string.characters())
, m_length(string.length())
{
}
StringView::StringView(const FlyString& string)
: m_impl(string.impl())
, m_characters(string.characters())
: m_characters(string.characters())
, m_length(string.length())
{
}
@ -251,8 +249,6 @@ unsigned StringView::hash() const
{
if (is_empty())
return 0;
if (m_impl)
return m_impl->hash();
return string_hash(characters_without_null_termination(), length());
}