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LibJS: Make Map iterators independent of the underlying hashmap

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This implements ordered maps as a pair of an RBTree for key order, and
an underlying unordered hash map for storage.
Fixes (part of) #11004.
This commit is contained in:
Ali Mohammad Pur 2022-02-09 16:34:52 +03:30 • committed by Linus Groh
parent e7dea10381
commit 4a73ec07c5
8 changed files with 153 additions and 19 deletions
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84
Userland/Libraries/LibJS/Runtime/Map.h
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@ -6,7 +6,9 @@
#pragma once
#include <AK/Concepts.h>
#include <AK/HashMap.h>
#include <AK/RedBlackTree.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/Object.h>
#include <LibJS/Runtime/Value.h>
@ -22,13 +24,89 @@ public:
explicit Map(Object& prototype);
virtual ~Map() override;
OrderedHashMap<Value, Value, ValueTraits> const& entries() const { return m_entries; };
OrderedHashMap<Value, Value, ValueTraits>& entries() { return m_entries; };
void map_clear();
bool map_remove(Value const&);
Optional<Value> map_get(Value const&) const;
bool map_has(Value const&) const;
void map_set(Value const&, Value);
size_t map_size() const;
struct EndIterator {
};
template<bool IsConst>
struct IteratorImpl {
bool is_end() const
{
if (m_index.has_value()) {
return m_map.m_keys.begin_from(*m_index).is_end()
&& m_map.m_keys.find_smallest_not_below_iterator(*m_index).is_end();
}
// First attempt and no iteration, ask the map if it has anything.
return m_map.m_keys.is_empty();
}
IteratorImpl& operator++()
{
if (auto it = m_map.m_keys.find_smallest_not_below_iterator(ensure_index() + 1); it.is_end())
m_index = m_map.m_next_insertion_id;
else
m_index = it.key();
return *this;
}
decltype(auto) operator*()
{
return *m_map.m_entries.find(*m_map.m_keys.begin_from(ensure_index()));
}
decltype(auto) operator*() const
{
return *m_map.m_entries.find(*m_map.m_keys.begin_from(ensure_index()));
}
bool operator==(IteratorImpl const& other) const { return m_index == other.m_index && &m_map == &other.m_map; }
bool operator==(EndIterator const&) const { return is_end(); }
private:
friend class Map;
IteratorImpl(Map const& map) requires(IsConst)
: m_map(map)
{
}
IteratorImpl(Map& map) requires(!IsConst)
: m_map(map)
{
}
size_t ensure_index()
{
if (!m_index.has_value()) {
VERIFY(!m_map.m_keys.is_empty());
m_index = m_map.m_keys.begin().key();
}
return *m_index;
}
Conditional<IsConst, Map const&, Map&> m_map;
mutable Optional<size_t> m_index;
};
using Iterator = IteratorImpl<false>;
using ConstIterator = IteratorImpl<true>;
ConstIterator begin() const { return { *this }; }
Iterator begin() { return { *this }; }
EndIterator end() const { return {}; }
private:
virtual void visit_edges(Visitor& visitor) override;
OrderedHashMap<Value, Value, ValueTraits> m_entries;
size_t m_next_insertion_id { 0 };
RedBlackTree<size_t, Value> m_keys;
HashMap<Value, Value, ValueTraits> m_entries;
};
}