LibURL/Pattern: Add a URL Pattern 'Part' representation

Author: https://github.com/shannonbooth
Commit: https://github.com/LadybirdBrowser/ladybird/commit/88bea4a7179
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3847
Reviewed-by: https://github.com/trflynn89

Libraries/LibURL/CMakeLists.txt

@@ -10,6 +10,7 @@ set(SOURCES
     Pattern/Canonicalization.cpp
     Pattern/ConstructorStringParser.cpp
     Pattern/Init.cpp
+    Pattern/Part.cpp
     Pattern/Pattern.cpp
     Pattern/String.cpp
     Pattern/Tokenizer.cpp

Libraries/LibURL/Pattern/Part.cpp

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2025, Shannon Booth <shannon@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibURL/Pattern/Component.h>
+#include <LibURL/Pattern/Part.h>
+
+namespace URL::Pattern {
+
+Part::Part(Type type, String value, Modifier modifier)
+    : type(type)
+    , value(move(value))
+    , modifier(modifier)
+{
+}
+
+Part::Part(Type type, String value, Modifier modifier, String name, String prefix, String suffix)
+    : type(type)
+    , value(move(value))
+    , modifier(modifier)
+    , name(move(name))
+    , prefix(move(prefix))
+    , suffix(move(suffix))
+{
+}
+
+StringView Part::type_to_string(Part::Type type)
+{
+    switch (type) {
+    case Type::FixedText:
+        return "FixedText"sv;
+    case Type::Regexp:
+        return "Regexp"sv;
+    case Type::SegmentWildcard:
+        return "SegmentWildcard"sv;
+    case Type::FullWildcard:
+        return "FullWildcard"sv;
+    }
+
+    VERIFY_NOT_REACHED();
+}
+
+// https://urlpattern.spec.whatwg.org/#convert-a-modifier-to-a-string
+StringView Part::convert_modifier_to_string(Part::Modifier modifier)
+{
+    // 1. If modifier is "zero-or-more", then return "*".
+    if (modifier == Modifier::ZeroOrMore)
+        return "*"sv;
+
+    // 2. If modifier is "optional", then return "?".
+    if (modifier == Modifier::Optional)
+        return "?"sv;
+
+    // 3. If modifier is "one-or-more", then return "+".
+    if (modifier == Modifier::OneOrMore)
+        return "+"sv;
+
+    // 4. Return the empty string.
+    return ""sv;
+}
+
+}

Libraries/LibURL/Pattern/Part.h

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2025, Shannon Booth <shannon@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Function.h>
+#include <AK/String.h>
+
+namespace URL::Pattern {
+
+// https://urlpattern.spec.whatwg.org/#part
+struct Part {
+    // https://urlpattern.spec.whatwg.org/#part-type
+    enum class Type {
+        // The part represents a simple fixed text string.
+        FixedText,
+
+        // The part represents a matching group with a custom regular expression.
+        Regexp,
+
+        // The part represents a matching group that matches code points up to the next separator code point. This is
+        // typically used for a named group like ":foo" that does not have a custom regular expression.
+        SegmentWildcard,
+
+        // The part represents a matching group that greedily matches all code points. This is typically used for
+        // the "*" wildcard matching group.
+        FullWildcard,
+    };
+
+    // https://urlpattern.spec.whatwg.org/#part-modifier
+    enum class Modifier {
+        // The part does not have a modifier.
+        None,
+
+        // The part has an optional modifier indicated by the U+003F (?) code point.
+        Optional,
+
+        // The part has a "zero or more" modifier indicated by the U+002A (*) code point.
+        ZeroOrMore,
+
+        // The part has a "one or more" modifier indicated by the U+002B (+) code point.
+        OneOrMore,
+    };
+
+    static StringView convert_modifier_to_string(Modifier);
+    static StringView type_to_string(Type);
+
+    Part(Type, String value, Modifier);
+    Part(Type, String value, Modifier, String name, String prefix, String suffix);
+
+    // https://urlpattern.spec.whatwg.org/#part-type
+    // A part has an associated type, a string, which must be set upon creation.
+    Type type {};
+
+    // https://urlpattern.spec.whatwg.org/#part-value
+    // A part has an associated value, a string, which must be set upon creation.
+    String value;
+
+    // https://urlpattern.spec.whatwg.org/#part-modifier
+    // A part has an associated modifier a string, which must be set upon creation.
+    Modifier modifier;
+
+    // https://urlpattern.spec.whatwg.org/#part-name
+    // A part has an associated name, a string, initially the empty string.
+    String name;
+
+    // https://urlpattern.spec.whatwg.org/#part-prefix
+    // A part has an associated prefix, a string, initially the empty string.
+    String prefix;
+
+    // https://urlpattern.spec.whatwg.org/#part-suffix
+    // A part has an associated suffix, a string, initially the empty string.
+    String suffix;
+};
+
+}