iOS File Dialog: Support setting name filters

Fixes: QTBUG-93624
Pick-to: 6.5
Change-Id: I2e1b522d572fd36f58a3de90f0a685f5d22dfeeb
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

src/plugins/platforms/ios/qiosdocumentpickercontroller.mm

@@ -14,6 +14,16 @@
 {
     NSMutableArray <UTType *> *docTypes = [[[NSMutableArray alloc] init] autorelease];
 
+    QStringList nameFilters = fileDialog->options()->nameFilters();
+    if (!nameFilters.isEmpty() && (fileDialog->options()->fileMode() != QFileDialogOptions::Directory
+                               || fileDialog->options()->fileMode() != QFileDialogOptions::DirectoryOnly))
+    {
+        QStringList results;
+        for (const QString &filter : nameFilters)
+            results.append(QPlatformFileDialogHelper::cleanFilterList(filter));
+
+        docTypes = [self computeAllowedFileTypes:results];
+    } else {
         switch (fileDialog->options()->fileMode()) {
         case QFileDialogOptions::AnyFile:
         case QFileDialogOptions::ExistingFile:
@@ -28,6 +38,7 @@
             [docTypes addObject:[UTType typeWithIdentifier:(__bridge NSString *)kUTTypeFolder]];
             break;
         }
+    }
 
     if (self = [super initForOpeningContentTypes:docTypes]) {
         m_fileDialog = fileDialog;
@@ -75,4 +86,25 @@
     emit m_fileDialog->reject();
 }
 
+- (NSMutableArray<UTType*>*)computeAllowedFileTypes:(QStringList)filters
+{
+    QStringList fileTypes;
+    for (const QString &filter : filters) {
+        if (filter.contains(u'?'))
+            continue;
+
+        if (filter.count(u'*') != 1)
+            continue;
+
+        auto extensions = filter.split('.', Qt::SkipEmptyParts);
+        fileTypes += extensions.last();
+    }
+
+    NSMutableArray<UTType *> *result = [NSMutableArray<UTType *> arrayWithCapacity:fileTypes.size()];
+    for (const QString &string : fileTypes)
+        [result addObject:[UTType typeWithFilenameExtension:string.toNSString()]];
+
+    return result;
+}
+
 @end