LibHTML: Add LengthStyleValue and create those when parsing number values.

LibHTML/CSS/Length.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <AK/AKString.h>
+
 class Length {
 public:
     enum class Type {
@@ -20,6 +22,13 @@ public:
 
     int value() const { return m_value; }
 
+    String to_string() const
+    {
+        if (is_auto())
+            return "auto";
+        return String::format("%d [Length/Absolute]", m_value);
+    }
+
 private:
     Type m_type { Type::Auto };
     int m_value { 0 };

LibHTML/CSS/StyleValue.cpp

@@ -11,5 +11,15 @@ StyleValue::~StyleValue()
 
 NonnullRefPtr<StyleValue> StyleValue::parse(const StringView& str)
 {
-    return adopt(*new PrimitiveStyleValue(str));
+    String string(str);
+    bool ok;
+    int as_int = string.to_int(ok);
+    if (ok)
+        return adopt(*new LengthStyleValue(Length(as_int, Length::Type::Absolute)));
+    unsigned as_uint = string.to_uint(ok);
+    if (ok)
+        return adopt(*new LengthStyleValue(Length(as_uint, Length::Type::Absolute)));
+    if (string == "auto")
+        return adopt(*new LengthStyleValue(Length()));
+    return adopt(*new StringStyleValue(str));
 }

LibHTML/CSS/StyleValue.h

@@ -4,6 +4,7 @@
 #include <AK/RefCounted.h>
 #include <AK/RefPtr.h>
 #include <AK/StringView.h>
+#include <LibHTML/CSS/Length.h>
 
 class StyleValue : public RefCounted<StyleValue> {
 public:
@@ -11,11 +12,12 @@ public:
 
     virtual ~StyleValue();
 
-    enum Type {
+    enum class Type {
         Invalid,
         Inherit,
         Initial,
-        Primitive,
+        String,
+        Length,
     };
 
     Type type() const { return m_type; }
@@ -29,11 +31,11 @@ private:
     Type m_type { Type::Invalid };
 };
 
-class PrimitiveStyleValue : public StyleValue {
+class StringStyleValue : public StyleValue {
 public:
-    virtual ~PrimitiveStyleValue() override {}
+    virtual ~StringStyleValue() override {}
-    PrimitiveStyleValue(const String& string)
+    StringStyleValue(const String& string)
-        : StyleValue(Type::Primitive)
+        : StyleValue(Type::String)
         , m_string(string)
     {
     }
@@ -43,3 +45,18 @@ public:
 private:
     String m_string;
 };
+
+class LengthStyleValue : public StyleValue {
+public:
+    virtual ~LengthStyleValue() override {}
+    LengthStyleValue(const Length& length)
+        : StyleValue(Type::Length)
+        , m_length(length)
+    {
+    }
+
+    String to_string() const override { return m_length.to_string(); }
+
+private:
+    Length m_length;
+};