Fix a crash when a delayed reply would call a callback for an object that disappeared

libnymea-app-core/connection/awsclient.cpp

@@ -8,6 +8,7 @@
 #include <QSettings>
 #include <QUuid>
 #include <QTimer>
+#include <QPointer>
 
 #include "sigv4utils.h"
 
@@ -820,7 +821,7 @@ void AWSClient::getCredentialsForIdentity(const QString &identityId)
             if (qc.method == "fetchDevices") {
                 fetchDevices();
             } else if (qc.method == "postToMQTT") {
-                postToMQTT(qc.arg1, qc.arg2, qc.callback);
+                postToMQTT(qc.arg1, qc.arg2, qc.sender, qc.callback);
             } else if (qc.method == "deleteAccount") {
                 deleteAccount();
             } else if (qc.method == "registerPushNotificationEndpoint") {
@@ -837,7 +838,7 @@ bool AWSClient::tokensExpired() const
     return (m_accessTokenExpiry.addSecs(-10) < QDateTime::currentDateTime()) || (m_sessionTokenExpiry.addSecs(-10) < QDateTime::currentDateTime());
 }
 
-bool AWSClient::postToMQTT(const QString &boxId, const QString &timestamp, std::function<void(bool)> callback)
+bool AWSClient::postToMQTT(const QString &boxId, const QString &timestamp, QObject* sender, std::function<void (bool)> callback)
 {
     if (!isLoggedIn()) {
         qWarning() << "Cannot post to MQTT. Not logged in to AWS";
@@ -846,11 +847,13 @@ bool AWSClient::postToMQTT(const QString &boxId, const QString &timestamp, std::
     if (tokensExpired()) {
         qDebug() << "Cannot post to MQTT. Need to refresh the tokens first";
         refreshAccessToken();
-        QueuedCall::enqueue(m_callQueue, QueuedCall("postToMQTT", boxId, timestamp, callback));
+        QueuedCall::enqueue(m_callQueue, QueuedCall("postToMQTT", boxId, timestamp, sender, callback));
         return true; // So far it looks we're doing ok... let's return true
     }    
     QString topic = QString("%1/%2/proxy").arg(boxId).arg(QString(m_identityId));
 
+    QPointer<QObject> senderWatcher = QPointer<QObject>(sender);
+
     // This is somehow broken in AWS...
     // The Signature needs to be created with having the topic percentage-encoded twice
     // while the actual request needs to go out with it only being encoded once.
@@ -882,15 +885,21 @@ bool AWSClient::postToMQTT(const QString &boxId, const QString &timestamp, std::
 //    }
 //    qDebug() << "Payload:" << payload;
     QNetworkReply *reply = m_nam->post(request, payload);
-    QTimer::singleShot(5000, reply, [reply, callback](){
+    QTimer::singleShot(5000, reply, [reply, senderWatcher, callback](){
         reply->deleteLater();
         qWarning() << "Timeout posting to MQTT";
-        callback(false);
+        if (senderWatcher) {
+            callback(false);
+        }
     });
-    connect(reply, &QNetworkReply::finished, this, [reply, callback]() {
+    connect(reply, &QNetworkReply::finished, this, [reply, senderWatcher, callback]() {
         reply->deleteLater();
         QByteArray data = reply->readAll();
 //        qDebug() << "MQTT post reply" << data;
+        if (senderWatcher.isNull()) {
+            qDebug() << "Request object disappeared. Discarding MQTT reply...";
+            return;
+        }
         if (reply->error() != QNetworkReply::NoError) {
             qWarning() << "MQTT Network reply error" << reply->error() << reply->errorString();
             callback(false);
@@ -909,7 +918,6 @@ bool AWSClient::postToMQTT(const QString &boxId, const QString &timestamp, std::
             return;
         }
         callback(true);
-
     });
 
     return true;

libnymea-app-core/connection/awsclient.h

@@ -5,6 +5,7 @@
 #include <QNetworkRequest>
 #include <QDate>
 #include <QAbstractListModel>
+#include <QPointer>
 
 class QNetworkAccessManager;
 
@@ -117,7 +118,7 @@ public:
 
     Q_INVOKABLE void fetchDevices();
 
-    Q_INVOKABLE bool postToMQTT(const QString &boxId, const QString &timestamp, std::function<void(bool)> callback);
+    Q_INVOKABLE bool postToMQTT(const QString &boxId, const QString &timestamp, QObject* sender, std::function<void(bool)> callback);
     Q_INVOKABLE void getId();
 
     Q_INVOKABLE void registerPushNotificationEndpoint(const QString &registrationId, const QString &deviceDisplayName, const QString mobileDeviceId, const QString &mobileDeviceManufacturer, const QString &mobileDeviceModel);
@@ -184,13 +185,14 @@ private:
         QueuedCall(const QString &method): method(method) { }
         QueuedCall(const QString &method, const QString &arg1): method(method), arg1(arg1) { }
         QueuedCall(const QString &method, const QString &arg1, const QString &arg2, const QString &arg3, const QString &arg4, const QString &arg5): method(method), arg1(arg1), arg2(arg2), arg3(arg3), arg4(arg4), arg5(arg5) { }
-        QueuedCall(const QString &method, const QString &arg1, const QString &arg2, std::function<void(bool)> callback): method(method), arg1(arg1), arg2(arg2), callback(callback) {}
+        QueuedCall(const QString &method, const QString &arg1, const QString &arg2, QObject* sender, std::function<void(bool)> callback): method(method), arg1(arg1), arg2(arg2), sender(sender), callback(callback) {}
         QString method;
         QString arg1;
         QString arg2;
         QString arg3;
         QString arg4;
         QString arg5;
+        QPointer<QObject> sender;
         std::function<void(bool)> callback;
 
         static void enqueue(QList<QueuedCall> &queue, const QueuedCall &call) {

libnymea-app-core/connection/cloudtransport.cpp

@@ -5,6 +5,7 @@
 
 #include <QUrlQuery>
 #include <QHostInfo>
+#include <QPointer>
 
 using namespace remoteproxyclient;
 
@@ -52,7 +53,7 @@ bool CloudTransport::connect(const QUrl &url)
     m_url = url;
 
     m_timestamp = QDateTime::currentDateTime();
-    bool postResult = m_awsClient->postToMQTT(url.host(), QString::number(m_timestamp.toMSecsSinceEpoch()), [this](bool success) {
+    bool postResult = m_awsClient->postToMQTT(url.host(), QString::number(m_timestamp.toMSecsSinceEpoch()), QPointer<QObject>(this), [this](bool success) {
         if (success) {
             qDebug() << "MQTT Post done. Connecting to remote proxy";
             m_remoteproxyConnection->connectServer(QUrl("wss://remoteproxy.nymea.io"));