Qt::mightBeRichText: port to QAnyStringView

[ChangeLog][QtGui] Ported Qt::mightBeRichText() to QAnyStringView
(was: QString).

Change-Id: Ib5633ed45cba5f4f1211438397624574f7431908
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

src/gui/compat/removed_api.cpp

@@ -19,6 +19,13 @@ QT_USE_NAMESPACE
 
 #if QT_GUI_REMOVED_SINCE(6, 7)
 
+#include "qtextdocument.h"
+
+bool Qt::mightBeRichText(const QString& text)
+{
+    return Qt::mightBeRichText(qToStringViewIgnoringNull(text));
+}
+
 // #include "qotherheader.h"
 // // implement removed functions from qotherheader.h
 // order sections alphabetically

src/gui/text/qtextdocument.cpp

@@ -51,6 +51,8 @@ namespace {
 };
 
 /*!
+    \fn bool Qt::mightBeRichText(QAnyStringView text)
+
     Returns \c true if the string \a text is likely to be rich text;
     otherwise returns \c false.
 
@@ -60,18 +62,21 @@ namespace {
     for common cases, there is no guarantee.
 
     This function is defined in the \c <QTextDocument> header file.
-*/
-bool Qt::mightBeRichText(const QString& text)
+
+    \note In Qt versions prior to 6.7, this function took QString only.
+ */
+template <typename T>
+static bool mightBeRichTextImpl(T text)
 {
     if (text.isEmpty())
         return false;
     qsizetype start = 0;
 
-    while (start < text.size() && text.at(start).isSpace())
+    while (start < text.size() && QChar(text.at(start)).isSpace())
         ++start;
 
     // skip a leading <?xml ... ?> as for example with xhtml
-    if (QStringView{text}.mid(start, 5).compare("<?xml"_L1) == 0) {
+    if (text.mid(start, 5).compare("<?xml"_L1) == 0) {
         while (start < text.size()) {
             if (text.at(start) == u'?'
                 && start + 2 < text.size()
@@ -82,16 +87,16 @@ bool Qt::mightBeRichText(const QString& text)
             ++start;
         }
 
-        while (start < text.size() && text.at(start).isSpace())
+        while (start < text.size() && QChar(text.at(start)).isSpace())
             ++start;
     }
 
-    if (QStringView{text}.mid(start, 5).compare("<!doc"_L1, Qt::CaseInsensitive) == 0)
+    if (text.mid(start, 5).compare("<!doc"_L1, Qt::CaseInsensitive) == 0)
         return true;
     qsizetype open = start;
     while (open < text.size() && text.at(open) != u'<'
             && text.at(open) != u'\n') {
-        if (text.at(open) == u'&' &&  QStringView{text}.mid(open + 1, 3) == "lt;"_L1)
+        if (text.at(open) == u'&' && text.mid(open + 1, 3) == "lt;"_L1)
             return true; // support desperate attempt of user to see <...>
         ++open;
     }
@@ -100,13 +105,14 @@ bool Qt::mightBeRichText(const QString& text)
         if (close > -1) {
             QVarLengthArray<char16_t> tag;
             for (qsizetype i = open + 1; i < close; ++i) {
-                if (text[i].isDigit() || text[i].isLetter())
-                    tag.append(text[i].toLower().unicode());
-                else if (!tag.isEmpty() && text[i].isSpace())
+                const auto current = QChar(text[i]);
+                if (current.isDigit() || current.isLetter())
+                    tag.append(current.toLower().unicode());
+                else if (!tag.isEmpty() && current.isSpace())
                     break;
-                else if (!tag.isEmpty() && text[i] == u'/' && i + 1 == close)
+                else if (!tag.isEmpty() && current == u'/' && i + 1 == close)
                     break;
-                else if (!text[i].isSpace() && (!tag.isEmpty() || text[i] != u'!'))
+                else if (!current.isSpace() && (!tag.isEmpty() || current != u'!'))
                     return false; // that's not a tag
             }
 #ifndef QT_NO_TEXTHTMLPARSER
@@ -119,6 +125,16 @@ bool Qt::mightBeRichText(const QString& text)
     return false;
 }
 
+static bool mightBeRichTextImpl(QUtf8StringView text)
+{
+    return mightBeRichTextImpl(QLatin1StringView(QByteArrayView(text)));
+}
+
+bool Qt::mightBeRichText(QAnyStringView text)
+{
+    return text.visit([](auto text) { return mightBeRichTextImpl(text); });
+}
+
 /*!
     Converts the plain text string \a plain to an HTML-formatted
     paragraph while preserving most of its look.

src/gui/text/qtextdocument.h

@@ -35,7 +35,10 @@ class QTextCursor;
 
 namespace Qt
 {
+#if QT_GUI_REMOVED_SINCE(6, 7)
     Q_GUI_EXPORT bool mightBeRichText(const QString&);
+#endif
+    Q_GUI_EXPORT bool mightBeRichText(QAnyStringView);
     Q_GUI_EXPORT QString convertFromPlainText(const QString &plain, WhiteSpaceMode mode = WhiteSpacePre);
 }
 

tests/auto/gui/text/qtextdocument/tst_qtextdocument.cpp

@@ -743,6 +743,9 @@ void tst_QTextDocument::mightBeRichText_data()
                                 "    PUBLIC ""-//W3C//DTD XHTML 1.0 Strict//EN\" \"DTD/xhtml1-strict.dtd\">\n"
                                 "<html xmlns=\"http://www.w3.org/1999/xhtml\" xml:lang=\"en\" lang=\"en\">";
     QVERIFY(Qt::mightBeRichText(QString::fromLatin1(qtDocuHeader)));
+    QVERIFY(Qt::mightBeRichText(QLatin1StringView(qtDocuHeader)));
+    QVERIFY(QUtf8StringView(qtDocuHeader).isValidUtf8());
+    QVERIFY(Qt::mightBeRichText(QUtf8StringView(qtDocuHeader)));
     QTest::addColumn<QString>("input");
     QTest::addColumn<bool>("result");
 
@@ -762,6 +765,10 @@ void tst_QTextDocument::mightBeRichText()
     QFETCH(QString, input);
     QFETCH(bool, result);
     QCOMPARE(result, Qt::mightBeRichText(input));
+    QCOMPARE(result, Qt::mightBeRichText(QStringView(input)));
+    QCOMPARE(result, Qt::mightBeRichText(QUtf8StringView(input.toUtf8())));
+    QVERIFY(QtPrivate::isLatin1(input));
+    QCOMPARE(result, Qt::mightBeRichText(QLatin1StringView(input.toLatin1())));
 }
 
 Q_DECLARE_METATYPE(QTextDocumentFragment)