LibRegex: Allow Unicode escape sequences in capture group names

Unfortunately, this requires a slight divergence in the way the capture
group names are stored. Previously, the generated byte code would simply
store a view into the regex pattern string, so no string copying was
required.

Now, the escape sequences are decoded into a new string, and a vector
of all parsed capture group names are stored in a vector in the parser
result structure. The byte code then stores a view into the
corresponding string in that vector.

Tests/LibRegex/Regex.cpp

@@ -698,6 +698,9 @@ TEST_CASE(ECMA262_unicode_match)
         { "\\ud83d\\ud83d"sv, "\xed\xa0\xbd\xed\xa0\xbd"sv, true, ECMAScriptFlags::Unicode },
         { "(?<=.{3})f"sv, "abcdef"sv, true, ECMAScriptFlags::Unicode },
         { "(?<=.{3})f"sv, "abc😀ef"sv, true, ECMAScriptFlags::Unicode },
+        { "(?<𝓑𝓻𝓸𝔀𝓷>brown)"sv, "brown"sv, true, ECMAScriptFlags::Unicode },
+        { "(?<\\u{1d4d1}\\u{1d4fb}\\u{1d4f8}\\u{1d500}\\u{1d4f7}>brown)"sv, "brown"sv, true, ECMAScriptFlags::Unicode },
+        { "(?<\\ud835\\udcd1\\ud835\\udcfb\\ud835\\udcf8\\ud835\\udd00\\ud835\\udcf7>brown)"sv, "brown"sv, true, ECMAScriptFlags::Unicode },
     };
 
     for (auto& test : tests) {

Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.match.js

@@ -55,3 +55,18 @@ test("UTF-16", () => {
     expect("😀😀".match(/\ud83d/g)).toEqual(["\ud83d", "\ud83d"]);
     expect("😀😀".match(/\ude00/g)).toEqual(["\ude00", "\ude00"]);
 });
+
+test("escaped code points", () => {
+    var string = "The quick brown fox jumped over the lazy dog's back";
+
+    var re = /(?<𝓑𝓻𝓸𝔀𝓷>brown)/u;
+    expect(string.match(re).groups.𝓑𝓻𝓸𝔀𝓷).toBe("brown");
+
+    re = /(?<\u{1d4d1}\u{1d4fb}\u{1d4f8}\u{1d500}\u{1d4f7}>brown)/u;
+    expect(string.match(re).groups.𝓑𝓻𝓸𝔀𝓷).toBe("brown");
+    expect(string.match(re).groups.𝓑𝓻𝓸𝔀𝓷).toBe("brown");
+
+    re = /(?<\ud835\udcd1\ud835\udcfb\ud835\udcf8\ud835\udd00\ud835\udcf7>brown)/u;
+    expect(string.match(re).groups.𝓑𝓻𝓸𝔀𝓷).toBe("brown");
+    expect(string.match(re).groups.𝓑𝓻𝓸𝔀𝓷).toBe("brown");
+});

Userland/Libraries/LibRegex/RegexParser.cpp

@@ -195,7 +195,8 @@ Parser::Result Parser::parse(Optional<AllOptions> regex_options)
         move(m_parser_state.named_capture_groups_count),
         move(m_parser_state.match_length_minimum),
         move(m_parser_state.error),
-        move(m_parser_state.error_token)
+        move(m_parser_state.error_token),
+        m_parser_state.named_capture_groups.keys()
     };
 }
 
@@ -2009,21 +2010,30 @@ bool ECMA262Parser::parse_unicode_property_escape(PropertyEscape& property, bool
         [](Empty&) -> bool { VERIFY_NOT_REACHED(); });
 }
 
-StringView ECMA262Parser::read_capture_group_specifier(bool take_starting_angle_bracket)
+FlyString ECMA262Parser::read_capture_group_specifier(bool take_starting_angle_bracket)
 {
     if (take_starting_angle_bracket && !consume("<"))
         return {};
 
-    auto start_token = m_parser_state.current_token;
-    size_t offset = 0;
-    while (match(TokenType::Char) || match(TokenType::Dollar)) {
+    StringBuilder builder;
+    while (match(TokenType::Char) || match(TokenType::Dollar) || match(TokenType::LeftCurly) || match(TokenType::RightCurly)) {
         auto c = m_parser_state.current_token.value();
         if (c == ">")
             break;
-        offset += consume().value().length();
+
+        if (try_skip("\\u"sv)) {
+            if (auto code_point = consume_escaped_code_point(true); code_point.has_value()) {
+                builder.append_code_point(*code_point);
+            } else {
+                set_error(Error::InvalidNameForCaptureGroup);
+                return {};
+            }
+        } else {
+            builder.append(consume().value());
+        }
     }
 
-    StringView name { start_token.value().characters_without_null_termination(), offset };
+    FlyString name = builder.build();
     if (!consume(">") || name.is_empty())
         set_error(Error::InvalidNameForCaptureGroup);
 
@@ -2146,7 +2156,7 @@ bool ECMA262Parser::parse_capture_group(ByteCode& stack, size_t& match_length_mi
 
             stack.insert_bytecode_group_capture_left(group_index);
             stack.extend(move(capture_group_bytecode));
-            stack.insert_bytecode_group_capture_right(group_index, name);
+            stack.insert_bytecode_group_capture_right(group_index, name.view());
 
             match_length_minimum += length;
 

Userland/Libraries/LibRegex/RegexParser.h

@@ -53,6 +53,7 @@ public:
         size_t match_length_minimum;
         Error error;
         Token error_token;
+        Vector<FlyString> capture_groups;
     };
 
     explicit Parser(Lexer& lexer)
@@ -218,7 +219,7 @@ private:
     };
     StringView read_digits_as_string(ReadDigitsInitialZeroState initial_zero = ReadDigitsInitialZeroState::Allow, bool hex = false, int max_count = -1, int min_count = -1);
     Optional<unsigned> read_digits(ReadDigitsInitialZeroState initial_zero = ReadDigitsInitialZeroState::Allow, bool hex = false, int max_count = -1, int min_count = -1);
-    StringView read_capture_group_specifier(bool take_starting_angle_bracket = false);
+    FlyString read_capture_group_specifier(bool take_starting_angle_bracket = false);
 
     struct Script {
         Unicode::Script script {};