Add parent arg to QFileDialog::getOpenFileContent and saveFileContent

This change updates getOpenFileContent to provide a parent when the
non-WASM fallback to a QFileDialog is created, which avoids issues
where this call is made inside another application. Specifically,
if a QDialog is created lacking a parent to the main window, it will
prevent interaction with that dialog. This patch addresses that problem
with window modality.

This change also updates saveFileContent to provide a parent for
the fallback mechanism, so that both static APIs that interact
with WASM/non-WASM dialogs have comparable behavior.

The new parent argument is updated in the documentation. Documentation
is clarified in terms of usage outside Qt for WebAssembly.

[ChangeLog][QtWidgets][QFileDialog] Adds an overload to the
static methods getOpenFileContent and saveFileContent with a
new parent argument which always no-ops in the WASM environment.

Fixes: QTBUG-118396
Pick-to: 6.6 6.5
Change-Id: Ic59aee386631172d4a29b42fe11e5af318474a1d
Reviewed-by: Venugopal Shivashankar <Venugopal.Shivashankar@qt.io>
(cherry picked from commit 7c5cf8cae054954975a3e262f7fe3cd9897d67f4)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/widgets/compat/removed_api.cpp

@@ -78,7 +78,26 @@ QAction *QMenuBar::addAction(const QString &text, const QObject *receiver, const
 }
 #endif
 
+#endif // QT_WIDGETS_REMOVED_SINCE(6, 3)
+
+#if QT_WIDGETS_REMOVED_SINCE(6, 7)
+
+
+#if QT_CONFIG(filedialog)
+#include "qfiledialog.h"
+
+void QFileDialog::getOpenFileContent(const QString &nameFilter, const std::function<void(const QString &, const QByteArray &)> &fileOpenCompleted)
+{
+    QFileDialog::getOpenFileContent(nameFilter, fileOpenCompleted, nullptr);
+}
+
+void QFileDialog::saveFileContent(const QByteArray &fileContent, const QString &fileNameHint)
+{
+    saveFileContent(fileContent, fileNameHint, nullptr);
+}
+#endif
+
 // #include <qotherheader.h>
 // // implement removed functions from qotherheader.h
 
-#endif // QT_WIDGETS_REMOVED_SINCE(6, 3)
+#endif // QT_WIDGETS_REMOVED_SINCE(6, 7)

src/widgets/dialogs/qfiledialog.cpp

@@ -2276,12 +2276,13 @@ QList<QUrl> QFileDialog::getOpenFileUrls(QWidget *parent,
     This is a convenience static function that returns the content of a file
     selected by the user.
 
-    This function is used to access local files on Qt for WebAssembly, where the web
+    Use this function to access local files on Qt for WebAssembly, if the web sandbox
-    sandbox places restrictions on how such access can happen. Its implementation will
+    restricts file access. Its implementation enables displaying a native file dialog in
-    make the browser display a native file dialog, where the user makes the file selection
+    the browser, where the user selects a file based on the \a nameFilter parameter.
-    based on the parameter \a nameFilter.
 
-    It can also be used on other platforms, where it falls back to using QFileDialog.
+    \a parent is ignored on Qt for WebAssembly. Pass \a parent on other platforms, to make
+    the popup a child of another widget. If the platform doesn't support native file
+    dialogs, the function falls back to QFileDialog.
 
     The function is asynchronous and returns immediately. The \a fileOpenCompleted
     callback will be called when a file has been selected and its contents have been
@@ -2290,9 +2291,10 @@ QList<QUrl> QFileDialog::getOpenFileUrls(QWidget *parent,
     \snippet code/src_gui_dialogs_qfiledialog.cpp 15
     \since 5.13
 */
-void QFileDialog::getOpenFileContent(const QString &nameFilter, const std::function<void(const QString &, const QByteArray &)> &fileOpenCompleted)
+void QFileDialog::getOpenFileContent(const QString &nameFilter, const std::function<void(const QString &, const QByteArray &)> &fileOpenCompleted, QWidget *parent)
 {
 #ifdef Q_OS_WASM
+    Q_UNUSED(parent);
     auto openFileImpl = std::make_shared<std::function<void(void)>>();
     QString fileName;
     QByteArray fileContent;
@@ -2322,9 +2324,10 @@ void QFileDialog::getOpenFileContent(const QString &nameFilter, const std::funct
 
     (*openFileImpl)();
 #else
-    QFileDialog *dialog = new QFileDialog();
+    QFileDialog *dialog = new QFileDialog(parent);
     dialog->setFileMode(QFileDialog::ExistingFile);
     dialog->setNameFilter(nameFilter);
+    dialog->setAttribute(Qt::WA_DeleteOnClose);
 
     auto fileSelected = [=](const QString &fileName) {
         QByteArray fileContent;
@@ -2337,7 +2340,6 @@ void QFileDialog::getOpenFileContent(const QString &nameFilter, const std::funct
     };
 
     connect(dialog, &QFileDialog::fileSelected, dialog, fileSelected);
-    dialog->setAttribute(Qt::WA_DeleteOnClose);
     dialog->show();
 #endif
 }
@@ -2347,23 +2349,26 @@ void QFileDialog::getOpenFileContent(const QString &nameFilter, const std::funct
     a file name and location chosen by the user. \a fileNameHint can be provided to
     suggest a file name to the user.
 
-    This function is used to save files to the local file system on Qt for WebAssembly, where
+    Use this function to save content to local files on Qt for WebAssembly, if the web sandbox
-    the web sandbox places restrictions on how such access can happen. Its implementation will
+    restricts file access. Its implementation enables displaying a native file dialog in the
-    make the browser display a native file dialog, where the user makes the file selection.
+    browser, where the user specifies an output file based on the \a fileNameHint argument.
 
-    It can also be used on other platforms, where it falls back to using QFileDialog.
+    \a parent is ignored on Qt for WebAssembly. Pass \a parent on other platforms, to make
+    the popup a child of another widget. If the platform doesn't support native file
+    dialogs, the function falls back to QFileDialog.
 
     The function is asynchronous and returns immediately.
 
     \snippet code/src_gui_dialogs_qfiledialog.cpp 16
     \since 5.14
 */
-void QFileDialog::saveFileContent(const QByteArray &fileContent, const QString &fileNameHint)
+void QFileDialog::saveFileContent(const QByteArray &fileContent, const QString &fileNameHint, QWidget *parent)
 {
 #ifdef Q_OS_WASM
+    Q_UNUSED(parent);
     QWasmLocalFileAccess::saveFile(fileContent, fileNameHint.toStdString());
 #else
-    QFileDialog *dialog = new QFileDialog();
+    QFileDialog *dialog = new QFileDialog(parent);
     dialog->setAcceptMode(QFileDialog::AcceptSave);
     dialog->setFileMode(QFileDialog::AnyFile);
     dialog->selectFile(fileNameHint);

src/widgets/dialogs/qfiledialog.h

@@ -212,9 +212,21 @@ public:
                                        Options options = Options(),
                                        const QStringList &supportedSchemes = QStringList());
 
+    static void getOpenFileContent(const QString &nameFilter,
+                                   const std::function<void(const QString &, const QByteArray &)> &fileContentsReady,
+                                   QWidget *parent);
+
+    static void saveFileContent(const QByteArray &fileContent,
+                                const QString &fileNameHint,
+                                QWidget *parent = nullptr);
+
+#if QT_WIDGETS_REMOVED_SINCE(6, 7)
     static void getOpenFileContent(const QString &nameFilter,
                                    const std::function<void(const QString &, const QByteArray &)> &fileContentsReady);
-    static void saveFileContent(const QByteArray &fileContent, const QString &fileNameHint = QString());
+    static void saveFileContent(const QByteArray &fileContent,
+                                const QString &fileNameHint = QString());
+#endif
+
 
 protected:
     QFileDialog(const QFileDialogArgs &args);