From 844321d89fda5fc9424f9122f030f63ee5b29a31 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 25 Sep 2022 15:47:40 +0200
Subject: [PATCH] LibWeb: Teach CSS::StyleProperties to create CSS::Size values

You can now use StyleProperties::size_value(CSS::PropertyID) to extract
a CSS::Size for a given property.
---
 .../Libraries/LibWeb/CSS/Identifiers.json     |  2 +
 .../Libraries/LibWeb/CSS/StyleProperties.cpp  | 38 ++++++++++++++++++-
 .../Libraries/LibWeb/CSS/StyleProperties.h    |  1 +
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/Userland/Libraries/LibWeb/CSS/Identifiers.json b/Userland/Libraries/LibWeb/CSS/Identifiers.json
index afa64db372..24c25a7f94 100644
--- a/Userland/Libraries/LibWeb/CSS/Identifiers.json
+++ b/Userland/Libraries/LibWeb/CSS/Identifiers.json
@@ -163,8 +163,10 @@
   "lowercase",
   "ltr",
   "listbox",
+  "max-content",
   "medium",
   "middle",
+  "min-content",
   "minimal-ui",
   "monospace",
   "more",
diff --git a/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp b/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp
index 107f678f8a..ed2d2bafbd 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp
+++ b/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021-2022, Sam Atkins <atkinssj@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -44,6 +44,42 @@ NonnullRefPtr<StyleValue> StyleProperties::property(CSS::PropertyID property_id)
     return value.release_nonnull();
 }
 
+CSS::Size StyleProperties::size_value(CSS::PropertyID id) const
+{
+    auto value = property(id);
+    if (value->is_identifier()) {
+        switch (value->to_identifier()) {
+        case ValueID::Auto:
+            return CSS::Size::make_auto();
+        case ValueID::MinContent:
+            return CSS::Size::make_min_content();
+        case ValueID::MaxContent:
+            return CSS::Size::make_max_content();
+        case ValueID::None:
+            return CSS::Size::make_none();
+        default:
+            VERIFY_NOT_REACHED();
+        }
+    }
+
+    if (value->is_calculated())
+        return CSS::Size::make_length(CSS::Length::make_calculated(value->as_calculated()));
+
+    if (value->is_percentage())
+        return CSS::Size::make_percentage(value->as_percentage().percentage());
+
+    if (value->has_length()) {
+        auto length = value->to_length();
+        if (length.is_auto())
+            return CSS::Size::make_auto();
+        return CSS::Size::make_length(value->to_length());
+    }
+
+    // FIXME: Support `fit-content(<length>)`
+    dbgln("FIXME: Unsupported size value: `{}`, treating as `auto`", value->to_string());
+    return CSS::Size::make_auto();
+}
+
 Length StyleProperties::length_or_fallback(CSS::PropertyID id, Length const& fallback) const
 {
     auto value = property(id);
diff --git a/Userland/Libraries/LibWeb/CSS/StyleProperties.h b/Userland/Libraries/LibWeb/CSS/StyleProperties.h
index d03478477e..81dbe2619b 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleProperties.h
+++ b/Userland/Libraries/LibWeb/CSS/StyleProperties.h
@@ -41,6 +41,7 @@ public:
     void set_property(CSS::PropertyID, NonnullRefPtr<StyleValue> value);
     NonnullRefPtr<StyleValue> property(CSS::PropertyID) const;
 
+    CSS::Size size_value(CSS::PropertyID) const;
     Length length_or_fallback(CSS::PropertyID, Length const& fallback) const;
     LengthPercentage length_percentage_or_fallback(CSS::PropertyID, LengthPercentage const& fallback) const;
     Optional<LengthPercentage> length_percentage(CSS::PropertyID) const;