Fix a concurrency related crash in the socket api

Author: TheOneRing

changelog/unreleased/8664

@@ -0,0 +1,5 @@
+Bugfix: We fixed a potential crash in the socket api
+
+We fixed a potential concurrency related crash in the socket api.
+
+https://github.com/owncloud/client/pull/8664

src/gui/socketapi/socketapi.cpp

@@ -432,10 +432,7 @@ void SocketApi::slotRegisterPath(const QString &alias)
 
     Folder *f = FolderMan::instance()->folder(alias);
     if (f) {
-        const QString message = buildRegisterPathMessage(removeTrailingSlash(f->path()));
-        for (const auto &listener : qAsConst(_listeners)) {
-            listener->sendMessage(message);
-        }
+        broadcastMessage(buildRegisterPathMessage(removeTrailingSlash(f->path())));
     }
 
     _registeredAliases.insert(alias);
@@ -479,7 +476,9 @@ void SocketApi::slotUpdateFolderView(Folder *f)
 
 void SocketApi::broadcastMessage(const QString &msg, bool doWait)
 {
-    for (const auto &listener : qAsConst(_listeners)) {
+    // operate on a copy of the list to prevent concurrency issues
+    const auto clients = _listeners.values();
+    for (const auto &listener : clients) {
         listener->sendMessage(msg, doWait);
     }
 }
@@ -530,7 +529,9 @@ void SocketApi::broadcastStatusPushMessage(const QString &systemPath, SyncFileSt
     QString msg = buildMessage(QLatin1String("STATUS"), systemPath, fileStatus.toSocketAPIString());
     Q_ASSERT(!systemPath.endsWith('/'));
     uint directoryHash = qHash(systemPath.left(systemPath.lastIndexOf('/')));
-    for (const auto &listener : qAsConst(_listeners)) {
+    // operate on a copy of the list to prevent concurrency issues
+    const auto clients = _listeners.values();
+    for (const auto &listener : clients) {
         listener->sendMessageIfDirectoryMonitored(msg, directoryHash);
     }
 }