QMimeType: simplify implementation of filterString

As suggested by Ahmad Samir

Change-Id: I7f3ef29436a7725b6dceab72bd0f8b01756bf930
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/mimetypes/qmimetype.cpp

@@ -437,14 +437,8 @@ QString QMimeType::filterString() const
     const QStringList patterns = globPatterns();
     QString filter;
 
-    if (!patterns.empty()) {
+    if (!patterns.isEmpty()) {
-        filter += comment() + " ("_L1;
+        filter = comment() + " ("_L1 + patterns.join(u' ') + u')';
-        for (int i = 0; i < patterns.size(); ++i) {
-            if (i != 0)
-                filter += u' ';
-            filter += patterns.at(i);
-        }
-        filter +=  u')';
     }
 
     return filter;

tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp

@@ -782,6 +782,26 @@ void tst_QMimeDatabase::knownSuffix()
     QCOMPARE(db.suffixForFileName(QString::fromLatin1("foo.anim2")), QString()); // the glob is anim[0-9], no way to extract the extension without expensive regexp capturing
 }
 
+void tst_QMimeDatabase::filterString_data()
+{
+    QTest::addColumn<QString>("mimeType");
+    QTest::addColumn<QString>("expectedFilterString");
+
+    QTest::newRow("single-pattern") << "application/pdf"
+                                    << "PDF document (*.pdf)";
+    QTest::newRow("multiple-patterns-text-plain") << "text/plain"
+                                                  << "plain text document (*.txt *.asc *,v)";
+}
+
+void tst_QMimeDatabase::filterString()
+{
+    QFETCH(QString, mimeType);
+    QFETCH(QString, expectedFilterString);
+
+    QMimeDatabase db;
+    QCOMPARE(db.mimeTypeForName(mimeType).filterString(), expectedFilterString);
+}
+
 void tst_QMimeDatabase::symlinkToFifo() // QTBUG-48529
 {
 #if defined(Q_OS_UNIX) && !defined(Q_OS_INTEGRITY)

tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.h

@@ -45,6 +45,8 @@ private slots:
     void suffixes_data();
     void suffixes();
     void knownSuffix();
+    void filterString_data();
+    void filterString();
     void symlinkToFifo();
     void fromThreads();