Move the creation of the icon to the main thread to prevent crash

We also ensure that qApp is completely set up when we create the icon.

4 files changed, 33 insertions, 11 deletions

diff --git a/changelog/9417 b/changelog/9417
new file mode 100644
index 000000000..61aa80d65
--- /dev/null
+++ b/changelog/9417
@@ -0,0 +1,5 @@
+Bugfix: Fix possible crash
+
+We change the initialisation of a Windows icon to prevent a possible crash.
+
+https://github.com/owncloud/client/issues/9417
diff --git a/src/gui/guiutility.cpp b/src/gui/guiutility.cpp
index 00a9e2e93..830ac71e8 100644
--- a/src/gui/guiutility.cpp
+++ b/src/gui/guiutility.cpp
@@ -45,30 +45,39 @@ using namespace OCC;
 
 Q_LOGGING_CATEGORY(lcUtility, "gui.utility", QtInfoMsg)
 
+#ifdef Q_OS_WIN
 namespace {
 
-#ifdef Q_OS_WIN
 // TODO: 2.11 move to the new Platform class
 struct
 {
     HANDLE windowMessageWatcherEvent = CreateEventW(nullptr, true, false, nullptr);
     bool windowMessageWatcherRun = true;
+    std::thread *watcherThread = nullptr;
 } watchWMCtx;
+}
 
-void startShutdownWatcher()
+void Utility::startShutdownWatcher()
 {
+    if (watchWMCtx.watcherThread) {
+        return;
+    }
     // Qt only receives window message if a window was displayed at least once
     // create an invisible window to handle WM_ENDSESSION
     // We also block a system shutdown until we are properly shutdown our selfs
     // In the unlikely case that we require more than 5s Windows will require a fullscreen message
     // with our icon, title and the reason why we are blocking the shutdown.
-    new std::thread([] {
+
+    // ensure to initialise the icon in the main thread
+    HICON icon = {};
+    if (qobject_cast<QGuiApplication *>(qApp)) {
+        icon = QtWin::toHICON(Theme::instance()->applicationIcon().pixmap(64, 64));
+    }
+    watchWMCtx.watcherThread = new std::thread([icon] {
         WNDCLASS wc = {};
         wc.hInstance = GetModuleHandle(nullptr);
         wc.lpszClassName = L"ocWindowMessageWatcher";
-        if (qobject_cast<QGuiApplication *>(qApp)) {
-            wc.hIcon = QtWin::toHICON(Theme::instance()->applicationIcon().pixmap(64, 64));
-        }
+        wc.hIcon = icon;
         wc.lpfnWndProc = [](HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) -> LRESULT {
             //            qDebug() << MSG { hwnd, msg, wParam, lParam, 0, {} };
             if (msg == WM_QUERYENDSESSION) {
@@ -116,9 +125,8 @@ void startShutdownWatcher()
         SetEvent(watchWMCtx.windowMessageWatcherEvent);
     });
 }
-Q_COREAPP_STARTUP_FUNCTION(startShutdownWatcher);
 #endif
-}
+
 
 bool Utility::openBrowser(const QUrl &url, QWidget *errorWidgetParent)
 {
diff --git a/src/gui/guiutility.h b/src/gui/guiutility.h
index 141556b3d..964182d7a 100644
--- a/src/gui/guiutility.h
+++ b/src/gui/guiutility.h
@@ -51,6 +51,11 @@ namespace Utility {
 
     QIcon getCoreIcon(const QString &icon_name);
 
+#ifdef Q_OS_WIN
+    // utility thread that takes care of proper Windows logout handling
+    void startShutdownWatcher();
+#endif
+
 } // namespace Utility
 } // namespace OCC
 
diff --git a/src/gui/main.cpp b/src/gui/main.cpp
index 2224e6d38..9e164763f 100644
--- a/src/gui/main.cpp
+++ b/src/gui/main.cpp
@@ -22,9 +22,10 @@
 #endif
 
 #include "application.h"
-#include "theme.h"
-#include "common/utility.h"
 #include "cocoainitializer.h"
+#include "common/utility.h"
+#include "guiutility.h"
+#include "theme.h"
 
 #include "updater/updater.h"
 
@@ -63,8 +64,11 @@ int main(int argc, char **argv)
     // though it looks slightly less native. Check here after the
     // QApplication was constructed, but before any QWidget is
     // constructed.
-    if (app.devicePixelRatio() > 1)
+    if (app.devicePixelRatio() > 1) {
         QApplication::setStyle(QStringLiteral("fusion"));
+    }
+    // TODO: 2.11 move to platform class
+    Utility::startShutdownWatcher();
 #endif // Q_OS_WIN
 
 #ifndef Q_OS_WIN