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LibWeb: Stop putting the FormattingState nodes in a slow hash map

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Instead, put them in a Vector<OwnPtr<NodeState>>. Each layout node
has a unique index into the vector. It's a simple serial ID assigned
during layout tree construction. Every new layout restarts the sequence
at 0 for the next ICB.

This is a huge layout speed improvement on all content.
This commit is contained in:
Andreas Kling 2022-07-11 17:12:58 +02:00
parent f6a97ff7d5
commit 0cacaf025d
6 changed files with 45 additions and 45 deletions
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65
Userland/Libraries/LibWeb/Layout/FormattingState.cpp
View file

@ -12,48 +12,37 @@ namespace Web::Layout {
FormattingState::NodeState& FormattingState::get_mutable(NodeWithStyleAndBoxModelMetrics const& box)
{
if (m_lookup_cache.box == &box && m_lookup_cache.is_mutable)
return *m_lookup_cache.state;
auto serial_id = box.serial_id();
if (nodes[serial_id])
return *nodes[serial_id];
auto& node_state = [&]() -> NodeState& {
if (auto it = nodes.find(&box); it != nodes.end())
return *it->value;
for (auto const* ancestor = m_parent; ancestor; ancestor = ancestor->m_parent) {
if (auto it = ancestor->nodes.find(&box); it != ancestor->nodes.end()) {
auto cow_node_state = adopt_own(*new NodeState(*it->value));
auto* cow_node_state_ptr = cow_node_state.ptr();
nodes.set(&box, move(cow_node_state));
return *cow_node_state_ptr;
}
for (auto const* ancestor = m_parent; ancestor; ancestor = ancestor->m_parent) {
if (ancestor->nodes[serial_id]) {
auto cow_node_state = adopt_own(*new NodeState(*ancestor->nodes[serial_id]));
auto* cow_node_state_ptr = cow_node_state.ptr();
nodes[serial_id] = move(cow_node_state);
return *cow_node_state_ptr;
}
}
return *nodes.ensure(&box, [] { return adopt_own(*new NodeState); });
}();
m_lookup_cache = LookupCache { .box = &box, .state = &node_state, .is_mutable = true };
return node_state;
nodes[serial_id] = adopt_own(*new NodeState);
nodes[serial_id]->node = const_cast<NodeWithStyleAndBoxModelMetrics*>(&box);
return *nodes[serial_id];
}
FormattingState::NodeState const& FormattingState::get(NodeWithStyleAndBoxModelMetrics const& box) const
{
if (m_lookup_cache.box == &box)
return *m_lookup_cache.state;
auto serial_id = box.serial_id();
if (nodes[serial_id])
return *nodes[serial_id];
auto& node_state = [&]() -> NodeState const& {
if (auto it = nodes.find(&box); it != nodes.end())
return *it->value;
for (auto* ancestor = m_parent; ancestor; ancestor = ancestor->m_parent) {
if (auto it = ancestor->nodes.find(&box); it != ancestor->nodes.end())
return *it->value;
}
return *const_cast<FormattingState&>(*this).nodes.ensure(&box, [] { return adopt_own(*new NodeState); });
}();
const_cast<FormattingState*>(this)->m_lookup_cache = LookupCache { .box = &box, .state = const_cast<NodeState*>(&node_state), .is_mutable = false };
return node_state;
for (auto* ancestor = m_parent; ancestor; ancestor = ancestor->m_parent) {
if (ancestor->nodes[serial_id])
return *ancestor->nodes[serial_id];
}
const_cast<FormattingState*>(this)->nodes[serial_id] = adopt_own(*new NodeState);
const_cast<FormattingState*>(this)->nodes[serial_id]->node = const_cast<NodeWithStyleAndBoxModelMetrics*>(&box);
return *nodes[serial_id];
}
void FormattingState::commit()
@ -63,9 +52,11 @@ void FormattingState::commit()
HashTable<Layout::TextNode*> text_nodes;
for (auto& it : nodes) {
auto& node = const_cast<Layout::NodeWithStyleAndBoxModelMetrics&>(*it.key);
auto& node_state = *it.value;
for (auto& node_state_ptr : nodes) {
if (!node_state_ptr)
continue;
auto& node_state = *node_state_ptr;
auto& node = *node_state.node;
// Transfer box model metrics.
node.box_model().inset = { node_state.inset_top, node_state.inset_right, node_state.inset_bottom, node_state.inset_left };