QRegularExpression: add captureCount()

QRegularExpression::captureCount() returns the number of
capturing groups inside the regular expression pattern.

Change-Id: Ib90ce67c67d06ab2966f0c98bd91da21defc156d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 46 insertions, 0 deletions

diff --git a/src/corelib/tools/qregularexpression.cpp b/src/corelib/tools/qregularexpression.cpp
index 17988bdb31..7bbac0144b 100644
--- a/src/corelib/tools/qregularexpression.cpp
+++ b/src/corelib/tools/qregularexpression.cpp
@@ -1341,6 +1341,19 @@ void QRegularExpression::setPatternOptions(PatternOptions options)
 }
 
 /*!
+    Returns the number of capturing groups inside the pattern string,
+    or -1 if the regular expression is not valid.
+
+    \sa isValid()
+*/
+int QRegularExpression::captureCount() const
+{
+    if (!isValid()) // will compile the pattern
+        return -1;
+    return d->capturingCount;
+}
+
+/*!
     Returns true if the regular expression is a valid regular expression (that
     is, it contains no syntax errors, etc.), or false otherwise. Use
     errorString() to obtain a textual description of the error.
diff --git a/src/corelib/tools/qregularexpression.h b/src/corelib/tools/qregularexpression.h
index 13c7de7cab..3ca83c9e27 100644
--- a/src/corelib/tools/qregularexpression.h
+++ b/src/corelib/tools/qregularexpression.h
@@ -94,6 +94,8 @@ public:
     int patternErrorOffset() const;
     QString errorString() const;
 
+    int captureCount() const;
+
     enum MatchType {
         NormalMatch = 0,
         PartialPreferCompleteMatch,
diff --git a/tests/auto/corelib/tools/qregularexpression/tst_qregularexpression.cpp b/tests/auto/corelib/tools/qregularexpression/tst_qregularexpression.cpp
index 8365a09689..9430425532 100644
--- a/tests/auto/corelib/tools/qregularexpression/tst_qregularexpression.cpp
+++ b/tests/auto/corelib/tools/qregularexpression/tst_qregularexpression.cpp
@@ -73,6 +73,8 @@ private slots:
     void serialize();
     void operatoreq_data();
     void operatoreq();
+    void captureCount_data();
+    void captureCount();
 
 private:
     void provideRegularExpressions();
@@ -1198,6 +1200,35 @@ void tst_QRegularExpression::operatoreq()
     }
 }
 
+void tst_QRegularExpression::captureCount_data()
+{
+    QTest::addColumn<QString>("pattern");
+    QTest::addColumn<int>("captureCount");
+    QTest::newRow("captureCount01") << "a pattern" << 0;
+    QTest::newRow("captureCount02") << "a.*pattern" << 0;
+    QTest::newRow("captureCount03") << "(a) pattern" << 1;
+    QTest::newRow("captureCount04") << "(a).*(pattern)" << 2;
+    QTest::newRow("captureCount05") << "^(?<article>\\w+) (?<noun>\\w+)$" << 2;
+    QTest::newRow("captureCount06") << "^(\\w+) (?<word>\\w+) (.)$" << 3;
+    QTest::newRow("captureCount07") << "(?:non capturing) (capturing) (?<n>named) (?:non (capturing))" << 3;
+    QTest::newRow("captureCount08") << "(?|(a)(b)|(c)(d))" << 2;
+    QTest::newRow("captureCount09") << "(?|(a)(b)|(c)(d)(?:e))" << 2;
+    QTest::newRow("captureCount10") << "(?|(a)(b)|(c)(d)(e)) (f)(g)" << 5;
+    QTest::newRow("captureCount11") << "(?|(a)(b)|(c)(d)(e)) (f)(?:g)" << 4;
+    QTest::newRow("captureCount_invalid01") << "(.*" << -1;
+    QTest::newRow("captureCount_invalid02") << "\\" << -1;
+    QTest::newRow("captureCount_invalid03") << "(?<noun)" << -1;
+}
+
+void tst_QRegularExpression::captureCount()
+{
+    QFETCH(QString, pattern);
+    QRegularExpression re(pattern);
+    QTEST(re.captureCount(), "captureCount");
+    if (!re.isValid())
+        QCOMPARE(re.captureCount(), -1);
+}
+
 QTEST_APPLESS_MAIN(tst_QRegularExpression)
 
 #include "tst_qregularexpression.moc"