LibWeb/CSS: Implement CSSMathMax

Basically the same as CSSMathMin.

Libraries/LibWeb/CSS/CSSMathMax.cpp

@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "CSSMathMax.h"
+#include <LibWeb/Bindings/CSSMathMaxPrototype.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/CSS/CSSMathNegate.h>
+#include <LibWeb/CSS/CSSNumericArray.h>
+#include <LibWeb/WebIDL/DOMException.h>
+#include <LibWeb/WebIDL/ExceptionOr.h>
+
+namespace Web::CSS {
+
+GC_DEFINE_ALLOCATOR(CSSMathMax);
+
+GC::Ref<CSSMathMax> CSSMathMax::create(JS::Realm& realm, NumericType type, GC::Ref<CSSNumericArray> values)
+{
+    return realm.create<CSSMathMax>(realm, move(type), move(values));
+}
+
+// https://drafts.css-houdini.org/css-typed-om-1/#dom-cssmathmin-cssmathmin
+WebIDL::ExceptionOr<GC::Ref<CSSMathMax>> CSSMathMax::construct_impl(JS::Realm& realm, Vector<CSSNumberish> values)
+{
+    // The CSSMathMin(...args) and CSSMathMax(...args) constructors are defined identically to the above, except that
+    // in the last step they return a new CSSMathMin or CSSMathMax object, respectively.
+    // NB: So, the steps below are a modification of the CSSMathSum steps.
+
+    // 1. Replace each item of args with the result of rectifying a numberish value for the item.
+    GC::RootVector<GC::Ref<CSSNumericValue>> converted_values { realm.heap() };
+    converted_values.ensure_capacity(values.size());
+    for (auto const& value : values) {
+        converted_values.append(rectify_a_numberish_value(realm, value));
+    }
+
+    // 2. If args is empty, throw a SyntaxError.
+    if (converted_values.is_empty())
+        return WebIDL::SyntaxError::create(realm, "Cannot create an empty CSSMathMax"_utf16);
+
+    // 3. Let type be the result of adding the types of all the items of args. If type is failure, throw a TypeError.
+    auto type = converted_values.first()->type();
+    bool first = true;
+    for (auto const& value : converted_values) {
+        if (first) {
+            first = false;
+            continue;
+        }
+        if (auto added_types = type.added_to(value->type()); added_types.has_value()) {
+            type = added_types.release_value();
+        } else {
+            return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, "Cannot create a CSSMathMax with values of incompatible types"sv };
+        }
+    }
+
+    // 4. Return a new CSSMathMax whose values internal slot is set to args.
+    auto values_array = CSSNumericArray::create(realm, { converted_values });
+    return CSSMathMax::create(realm, move(type), move(values_array));
+}
+
+CSSMathMax::CSSMathMax(JS::Realm& realm, NumericType type, GC::Ref<CSSNumericArray> values)
+    : CSSMathValue(realm, Bindings::CSSMathOperator::Max, move(type))
+    , m_values(move(values))
+{
+}
+
+CSSMathMax::~CSSMathMax() = default;
+
+void CSSMathMax::initialize(JS::Realm& realm)
+{
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(CSSMathMax);
+    Base::initialize(realm);
+}
+
+void CSSMathMax::visit_edges(Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_values);
+}
+
+// https://drafts.css-houdini.org/css-typed-om-1/#serialize-a-cssmathvalue
+String CSSMathMax::serialize_math_value(Nested, Parens) const
+{
+    // NB: Only steps 1 and 2 apply here.
+    // 1. Let s initially be the empty string.
+    StringBuilder s;
+
+    // 2. If this is a CSSMathMin or CSSMathMax:
+    {
+        // 1. Append "min(" or "max(" to s, as appropriate.
+        s.append("max("sv);
+
+        // 2. For each arg in this’s values internal slot, serialize arg with nested and paren-less both true, and
+        //    append the result to s, appending a ", " between successive values.
+        bool first = true;
+        for (auto const& arg : m_values->values()) {
+            if (first) {
+                first = false;
+            } else {
+                s.append(", "sv);
+            }
+            s.append(arg->to_string({ .nested = true, .parenless = true }));
+        }
+
+        // 3. Append ")" to s and return s.
+        s.append(")"sv);
+        return s.to_string_without_validation();
+    }
+}
+
+// https://drafts.css-houdini.org/css-typed-om-1/#dom-cssmathmin-values
+GC::Ref<CSSNumericArray> CSSMathMax::values() const
+{
+    return m_values;
+}
+
+}