From b289f97a65f352471a3416f375276dc5e7abfacf Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sat, 15 Oct 2022 13:46:15 +0200
Subject: [PATCH] LibWeb: Split intrinsic heights cache by definite available
 widths

As it turns out, we sometimes query the intrinsic height of a box before
having fully resolved and/or constrained its containing block. Because
of this, we may enter intrinsic sizing with different amounts of
available width for the same box.

To accommodate this scenario, we now allow caching of multiple intrinsic
heights, separated by the amount of available width provided as input.
---
 Userland/Libraries/LibWeb/Layout/FormattingContext.cpp | 4 ++--
 Userland/Libraries/LibWeb/Layout/LayoutState.h         | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/Userland/Libraries/LibWeb/Layout/FormattingContext.cpp b/Userland/Libraries/LibWeb/Layout/FormattingContext.cpp
index 0f1532d9fb..dfac2822d3 100644
--- a/Userland/Libraries/LibWeb/Layout/FormattingContext.cpp
+++ b/Userland/Libraries/LibWeb/Layout/FormattingContext.cpp
@@ -1183,7 +1183,7 @@ float FormattingContext::calculate_min_content_height(Layout::Box const& box, Av
         auto& root_state = m_state.m_root;
         auto& cache = *root_state.intrinsic_sizes.ensure(&box, [] { return adopt_own(*new LayoutState::IntrinsicSizes); });
         if (available_width.is_definite()) {
-            cache_slot = &cache.min_content_height_with_definite_available_width;
+            cache_slot = &cache.min_content_height_with_definite_available_width.ensure(available_width.to_px());
         } else if (available_width.is_min_content()) {
             cache_slot = &cache.min_content_height_with_min_content_available_width;
         } else if (available_width.is_max_content()) {
@@ -1228,7 +1228,7 @@ float FormattingContext::calculate_max_content_height(Layout::Box const& box, Av
         auto& root_state = m_state.m_root;
         auto& cache = *root_state.intrinsic_sizes.ensure(&box, [] { return adopt_own(*new LayoutState::IntrinsicSizes); });
         if (available_width.is_definite()) {
-            cache_slot = &cache.max_content_height_with_definite_available_width;
+            cache_slot = &cache.max_content_height_with_definite_available_width.ensure(available_width.to_px());
         } else if (available_width.is_min_content()) {
             cache_slot = &cache.max_content_height_with_min_content_available_width;
         } else if (available_width.is_max_content()) {
diff --git a/Userland/Libraries/LibWeb/Layout/LayoutState.h b/Userland/Libraries/LibWeb/Layout/LayoutState.h
index a85eae6e5e..ec1071e390 100644
--- a/Userland/Libraries/LibWeb/Layout/LayoutState.h
+++ b/Userland/Libraries/LibWeb/Layout/LayoutState.h
@@ -162,9 +162,9 @@ struct LayoutState {
         Optional<float> max_content_width;
 
         // NOTE: Since intrinsic heights depend on the amount of available width, we have to cache
-        //       three separate results, depending on the available width at the time of calculation.
-        Optional<float> min_content_height_with_definite_available_width;
-        Optional<float> max_content_height_with_definite_available_width;
+        //       three separate kinds of results, depending on the available width at the time of calculation.
+        HashMap<float, Optional<float>> min_content_height_with_definite_available_width;
+        HashMap<float, Optional<float>> max_content_height_with_definite_available_width;
         Optional<float> min_content_height_with_min_content_available_width;
         Optional<float> max_content_height_with_min_content_available_width;
         Optional<float> min_content_height_with_max_content_available_width;