Use possessive quantifiers to optimise regex matching performance

See 'ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS' section at:
https://pcre.org/pcre.txt

Thanks to Giuseppe D'Angelo for pointing that out.

src/autotests/HotSpotFilterTest.cpp

@@ -12,35 +12,71 @@ QTEST_GUILESS_MAIN(HotSpotFilterTest)
 void HotSpotFilterTest::testUrlFilterRegex_data()
 {
     QTest::addColumn<QString>("url");
+    QTest::addColumn<QString>("expectedUrl");
     QTest::addColumn<bool>("matchResult");
 
     // A space, \n, or \t before the url to match what happens at runtime,
     // i.e. to match "http" but not "foohttp"
-    QTest::newRow("url_simple") << " https://api.kde.org" << true;
-    QTest::newRow("url_with_port") << "\nhttps://api.kde.org:2098" << true;
-    QTest::newRow("url_with_path") << "https://api.kde.org/path/to/somewhere" << true;
-    QTest::newRow("url_with_query") << "https://user:pass@api.kde.org?somequery=foo" << true;
-    QTest::newRow("url_with_port_path") << " https://api.kde.org:2098/path/to/somewhere" << true;
-    QTest::newRow("url_with_user_password") << "\thttps://user:blah@api.kde.org" << true;
-    QTest::newRow("url_with_user_password_port_fragment") << " https://user:blah@api.kde.org:2098#fragment" << true;
-    QTest::newRow("url_all_bells") << " https://user:pass@api.kde.org:2098/path/to/somewhere?somequery=foo#fragment" << true;
-    QTest::newRow("uppercase") << " https://invent.kde.org/frameworks/ktexteditor/-/blob/master/README.md" << true;
-    QTest::newRow("markup") << " [https://foobar](https://foobar)" << true;
-
-    QTest::newRow("bad_url_no_scheme") << QStringLiteral(" www.kde.org") << false;
+    QTest::newRow("url_simple") << " https://api.kde.org"
+                                << "https://api.kde.org" << true;
+    QTest::newRow("url_with_port") << "\nhttps://api.kde.org:2098"
+                                   << "https://api.kde.org:2098" << true;
+    QTest::newRow("url_with_path") << "https://api.kde.org/path/to/somewhere"
+                                   << "https://api.kde.org/path/to/somewhere" << true;
+    QTest::newRow("url_with_query") << "https://user:pass@api.kde.org?somequery=foo"
+                                    << "https://user:pass@api.kde.org?somequery=foo" << true;
+    QTest::newRow("url_with_port_path") << " https://api.kde.org:2098/path/to/somewhere"
+                                        << "https://api.kde.org:2098/path/to/somewhere" << true;
+    QTest::newRow("url_with_user_password") << "\thttps://user:blah@api.kde.org"
+                                            << "https://user:blah@api.kde.org" << true;
+    QTest::newRow("url_with_user_password_port_fragment") << " https://user:blah@api.kde.org:2098#fragment"
+                                                          << "https://user:blah@api.kde.org:2098#fragment" << true;
+    QTest::newRow("url_all_bells") << " https://user:pass@api.kde.org:2098/path/to/somewhere?somequery=foo#fragment"
+                                   << "https://user:pass@api.kde.org:2098/path/to/somewhere?somequery=foo#fragment" << true;
+    QTest::newRow("uppercase") << " https://invent.kde.org/frameworks/ktexteditor/-/blob/master/README.md"
+                               << "https://invent.kde.org/frameworks/ktexteditor/-/blob/master/README.md" << true;
+    QTest::newRow("markup") << " [https://foobar](https://foobar)"
+                            << "https://foobar" << true;
+
+    QTest::newRow("bracket_before") << "[198]http://www.ietf.org/rfc/rfc2396.txt"
+                                    << "http://www.ietf.org/rfc/rfc2396.txt" << true;
+    QTest::newRow("quote_before") << "\"http://www.ietf.org/rfc/rfc2396.txt"
+                                  << "http://www.ietf.org/rfc/rfc2396.txt" << true;
+
+    QTest::newRow("file_scheme") << "file:///some/file"
+                                 << "file:///some/file" << true;
+
+    QTest::newRow("uppercase_host") << "https://EXAMPLE.com"
+                                    << "https://EXAMPLE.com" << true;
+    QTest::newRow("uppercase_query") << "https://example.com?fooOpt=barVal"
+                                     << "https://example.com?fooOpt=barVal" << true;
+    QTest::newRow("uppercase_fragment") << "https://example.com?fooOpt=barVal#FRAG"
+                                        << "https://example.com?fooOpt=barVal#FRAG" << true;
+
+    QTest::newRow("www") << " www.kde.org"
+                         << "www.kde.org" << true;
+
+    QTest::newRow("with_comma_in_path") << "https://example.com/foo,bar"
+                                        << "https://example.com/foo,bar" << true;
+
+    QTest::newRow("empty_query") << "http://example.com/?"
+                                 << "http://example.com" << true;
+    QTest::newRow("empty_fragment") << "http://example.com/#"
+                                    << "http://example.com" << true;
 }
 
 void HotSpotFilterTest::testUrlFilterRegex()
 {
     QFETCH(QString, url);
+    QFETCH(QString, expectedUrl);
     QFETCH(bool, matchResult);
 
     const QRegularExpression &regex = Konsole::UrlFilter::FullUrlRegExp;
     const QRegularExpressionMatch match = regex.match(url);
+    // qDebug() << match;
+
     QCOMPARE(match.hasMatch(), matchResult);
-    if (strcmp(QTest::currentDataTag(), "markup") == 0) {
-        QCOMPARE(match.capturedView(0), u"https://foobar");
-    } else if (matchResult) {
-        QCOMPARE(match.capturedView(0), url.trimmed());
+    if (matchResult) {
+        QCOMPARE(match.capturedView(0), expectedUrl);
     }
 }

src/filterHotSpots/UrlFilter.cpp

@@ -19,11 +19,17 @@ using namespace Konsole;
 // FullUrlRegExp is implemented based on:
 // https://datatracker.ietf.org/doc/html/rfc3986
 // See above URL for what "unreserved", "pct-encoded" ...etc mean, also
-// for the regex used for each part of the url being matched against
-
-// unreserved / pct-encoded / sub-delims
-// [a-z0-9\\-._~%!$&'()*+,;=]
-// The above string is used in various char[] below
+// for the regex used for each part of the url being matched against.
+//
+// It deviates from rfc3986:
+// - We only recognize URIs with authority (even if it is an empty authority)
+// - We match URIs starting with 'www.'
+// - "userinfo" is assumed to have a single ':' character
+// - We _don't_ match IPv6 addresses (e.g. http://[2010:836B:4179::836B:4179])
+//   or IPvFuture
+// - "port" (':1234'), if present, is assumed to be non-empty
+// - We don't check the validity of percent-encoded characters
+//   (e.g. "www.example.com/foo%XXbar")
 
 // All () groups are non-capturing (by using "(?:)" notation)
 // less bookkeeping on the PCRE engine side
@@ -31,32 +37,37 @@ using namespace Konsole;
 // scheme://
 // - Must start with an ASCII letter, preceeded by any non-word character,
 //   so "http" but not "mhttp"
-static const char scheme[] = "(?<=^|\\s|\\W)(?:[a-z][a-z0-9+\\-.]*://)";
+static const char scheme_or_www[] = "(?<=^|[\\s\\[\\]()'\"])(?:www\\.|[a-z][a-z0-9+\\-.]*+://)";
+
+// unreserved / pct-encoded / sub-delims
+#define COMMON_1 "a-z0-9\\-._~%!$&'()*+,;="
 
+/* clang-format off */
 // user:password@
 static const char userInfo[] =
     "(?:"
-    "[a-z0-9\\-._~%!$&'()*+,;=]+?:?"
-    "[a-z0-9\\-._~%!$&'()*+,;=]+@"
-    ")?";
-static const char host[] = "(?:[a-z0-9\\-._~%!$&'()*+,;=]+)"; // www.foo.bar
-static const char port[] = "(?::[0-9]+)?"; // :1234
-static const char path[] = "(?:[a-zA-Z0-9\\-._~%!$&'()*+,;=:@/]+)?"; // /path/to/some/place
-static const char query[] = "(?:\\?[a-z0-9\\-._~%!$&'()*+,;=:@/]+)?"; // "?somequery=bar"
-static const char fragment[] = "(?:#[a-z0-9/?]+)?";
+    "[" COMMON_1 "]+?:?"
+    "[" COMMON_1 "]++@"
+    ")?+";
+static const char host[] = "(?:[" COMMON_1 "]*+)"; // www.foo.bar
+static const char port[] = "(?::[0-9]+)?+"; // :1234
+
+#define COMMON_2 "a-z0-9\\-._~%!$&'()*+,;=:@/"
+static const char path[] = "(?:/[" COMMON_2 "]+)?+"; // /path/to/some/place
+static const char query[] = "(?:\\?[" COMMON_2 "]+)?+"; // "?somequery=bar"
+static const char fragment[] = "(?:#[" COMMON_2 "]+)?+"; // "#fragment"
 
 using LS1 = QLatin1String;
 
-/* clang-format off */
 const QRegularExpression UrlFilter::FullUrlRegExp(
-    LS1(scheme)
+    LS1(scheme_or_www)
     + LS1(userInfo)
     + LS1(host)
     + LS1(port)
     + LS1(path)
     + LS1(query)
     + LS1(fragment)
-    );
+    , QRegularExpression::CaseInsensitiveOption);
 /* clang-format on */
 
 /////////////////////////////////////////////