LibGC: Add GC::RootHashMap<...> template container

This is a GC-aware wrapper around AK::HashMap. Entry values are treated
as GC roots, much like the GC::RootVector we already had.

We also provide GC::OrderedRootHashMap as a convenience.
This commit is contained in:
Andreas Kling 2025-05-03 11:59:17 +02:00 committed by Andreas Kling
commit 11ece7de10
Notes: github-actions[bot] 2025-05-03 15:34:58 +00:00
6 changed files with 122 additions and 0 deletions

View file

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/*
* Copyright (c) 2025, Andreas Kling <andreas@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/HashMap.h>
#include <AK/IntrusiveList.h>
#include <AK/Vector.h>
#include <LibGC/Cell.h>
#include <LibGC/Forward.h>
#include <LibGC/HeapRoot.h>
namespace GC {
class RootHashMapBase {
public:
virtual void gather_roots(HashMap<Cell*, GC::HeapRoot>&) const = 0;
protected:
explicit RootHashMapBase(Heap&);
~RootHashMapBase();
void assign_heap(Heap*);
Heap* m_heap { nullptr };
IntrusiveListNode<RootHashMapBase> m_list_node;
public:
using List = IntrusiveList<&RootHashMapBase::m_list_node>;
};
template<typename K, typename V, typename KeyTraits = Traits<K>, typename ValueTraits = Traits<V>, bool IsOrdered = false>
class RootHashMap final
: public RootHashMapBase
, public HashMap<K, V, KeyTraits, ValueTraits, IsOrdered> {
using HashMapBase = HashMap<K, V, KeyTraits, ValueTraits, IsOrdered>;
public:
explicit RootHashMap(Heap& heap)
: RootHashMapBase(heap)
{
}
virtual ~RootHashMap() = default;
virtual void gather_roots(HashMap<Cell*, GC::HeapRoot>& roots) const override
{
for (auto& [key, value] : *this) {
if constexpr (IsBaseOf<NanBoxedValue, V>) {
if (value.is_cell())
roots.set(&const_cast<V&>(value).as_cell(), HeapRoot { .type = HeapRoot::Type::RootHashMap });
} else {
roots.set(value, HeapRoot { .type = HeapRoot::Type::RootHashMap });
}
}
}
};
template<typename K, typename V, typename KeyTraits = Traits<K>, typename ValueTraits = Traits<V>>
using OrderedRootHashMap = RootHashMap<K, V, KeyTraits, ValueTraits, true>;
}