Implement QRegularExpression overload for QPlainTextEdit::find

This patch adds the missing overload for QRegularExpression to match the
QRegExp one for QPlainTextEdit.

[ChangeLog][QtWidgets][QPlainTextEdit] Added QRegularExpression find()
method overload.

Change-Id: Id156971d3fa0372712bfa8b72a55550942a767e0
Reviewed-by: Luca Beldi <v.ronin@yahoo.it>
Reviewed-by: David Faure <david.faure@kdab.com>

src/widgets/widgets/qplaintextedit.cpp

@@ -2923,6 +2923,27 @@ bool QPlainTextEdit::find(const QRegExp &exp, QTextDocument::FindFlags options)
 }
 #endif
 
+/*!
+    \fn bool QTextEdit::find(const QRegularExpression &exp, QTextDocument::FindFlags options)
+
+    \since 5.13
+    \overload
+
+    Finds the next occurrence, matching the regular expression, \a exp, using the given
+    \a options. The QTextDocument::FindCaseSensitively option is ignored for this overload,
+    use QRegularExpression::CaseInsensitiveOption instead.
+
+    Returns \c true if a match was found and changes the cursor to select the match;
+    otherwise returns \c false.
+*/
+#if QT_CONFIG(regularexpression)
+bool QPlainTextEdit::find(const QRegularExpression &exp, QTextDocument::FindFlags options)
+{
+    Q_D(QPlainTextEdit);
+    return d->control->find(exp, options);
+}
+#endif
+
 /*!
     \fn void QPlainTextEdit::copyAvailable(bool yes)
 

src/widgets/widgets/qplaintextedit.h

@@ -60,6 +60,7 @@ class QMenu;
 class QPlainTextEditPrivate;
 class QMimeData;
 class QPagedPaintDevice;
+class QRegularExpression;
 
 class Q_WIDGETS_EXPORT QPlainTextEdit : public QAbstractScrollArea
 {
@@ -149,6 +150,9 @@ public:
 #ifndef QT_NO_REGEXP
     bool find(const QRegExp &exp, QTextDocument::FindFlags options = QTextDocument::FindFlags());
 #endif
+#if QT_CONFIG(regularexpression)
+    bool find(const QRegularExpression &exp, QTextDocument::FindFlags options = QTextDocument::FindFlags());
+#endif
 
     inline QString toPlainText() const
     { return document()->toPlainText(); }

tests/auto/widgets/widgets/qplaintextedit/tst_qplaintextedit.cpp

@@ -139,6 +139,11 @@ private slots:
     void findWithRegExp();
     void findBackwardWithRegExp();
     void findWithRegExpReturnsFalseIfNoMoreResults();
+#endif
+#if QT_CONFIG(regularexpression)
+    void findWithRegularExpression();
+    void findBackwardWithRegularExpression();
+    void findWithRegularExpressionReturnsFalseIfNoMoreResults();
 #endif
     void layoutAfterMultiLineRemove();
     void undoCommandRemovesAndReinsertsBlock();
@@ -1582,6 +1587,45 @@ void tst_QPlainTextEdit::findWithRegExpReturnsFalseIfNoMoreResults()
 }
 #endif
 
+#if QT_CONFIG(regularexpression)
+void tst_QPlainTextEdit::findWithRegularExpression()
+{
+    ed->setPlainText(QStringLiteral("arbitrary text"));
+    QRegularExpression rx("\\w{2}xt");
+
+    bool found = ed->find(rx);
+
+    QVERIFY(found);
+    QCOMPARE(ed->textCursor().selectedText(), QStringLiteral("text"));
+}
+
+void tst_QPlainTextEdit::findBackwardWithRegularExpression()
+{
+    ed->setPlainText(QStringLiteral("arbitrary text"));
+    QTextCursor cursor = ed->textCursor();
+    cursor.movePosition(QTextCursor::End);
+    ed->setTextCursor(cursor);
+    QRegularExpression rx("a\\w*t");
+
+    bool found = ed->find(rx, QTextDocument::FindBackward);
+
+    QVERIFY(found);
+    QCOMPARE(ed->textCursor().selectedText(), QStringLiteral("arbit"));
+}
+
+void tst_QPlainTextEdit::findWithRegularExpressionReturnsFalseIfNoMoreResults()
+{
+    ed->setPlainText(QStringLiteral("arbitrary text"));
+    QRegularExpression rx("t.xt");
+    ed->find(rx);
+
+    bool found = ed->find(rx);
+
+    QVERIFY(!found);
+    QCOMPARE(ed->textCursor().selectedText(), QStringLiteral("text"));
+}
+#endif
+
 void tst_QPlainTextEdit::layoutAfterMultiLineRemove()
 {
     ed->setVisible(true); // The widget must be visible to reproduce this bug.