Eradicate Q_FOREACH loops [2/2]: non-trivial cases

This patch contains two changes where there is a non-neglible chance
that through some indirect call the container we iterate over could be
modified.

In the listener case, it's not impossible that a listener de-registers
when it's notified. So take a copy.

In the polish_objects case, the 'initialized' flag is set before the
loop starts, and the only other reference to polish_objects, in
addPolishObject(), does not append to polish_objects in that case, but
sends the polish event directly. So use a consume loop, to release the
memory and the QPointers once they're dealt with.

Change-Id: I63d32e8a298ed5e1a7d5446434c421df80c0c795
Reviewed-by: Johan Helsing <johan.helsing@qt.io>
 

2 files changed, 3 insertions, 2 deletions

diff --git a/src/client/qwaylanddisplay.cpp b/src/client/qwaylanddisplay.cpp
index 53f5cfcea..cb4f190ad 100644
--- a/src/client/qwaylanddisplay.cpp
+++ b/src/client/qwaylanddisplay.cpp
@@ -346,7 +346,8 @@ void QWaylandDisplay::registry_global(uint32_t id, const QString &interface, uin
 
     mGlobals.append(RegistryGlobal(id, interface, version, registry));
 
-    foreach (Listener l, mRegistryListeners)
+    const auto copy = mRegistryListeners; // be prepared for listeners unregistering on notification
+    for (Listener l : copy)
         (*l.listener)(l.data, registry, id, interface, version);
 }
 
diff --git a/src/compositor/compositor_api/qwaylandcompositor.cpp b/src/compositor/compositor_api/qwaylandcompositor.cpp
index 36c995c3d..2d10c6384 100644
--- a/src/compositor/compositor_api/qwaylandcompositor.cpp
+++ b/src/compositor/compositor_api/qwaylandcompositor.cpp
@@ -234,7 +234,7 @@ void QWaylandCompositorPrivate::init()
 
     initialized = true;
 
-    Q_FOREACH (QPointer<QObject> object, polish_objects) {
+    for (const QPointer<QObject> &object : qExchange(polish_objects, {})) {
         if (object) {
             QEvent polishEvent(QEvent::Polish);
             QCoreApplication::sendEvent(object.data(), &polishEvent);