Intents: prevent a crash if a sent request is gc'ed too early

Not saving the result of IntentClient.sendIntentRequest could lead to
the GC deleting the IntentClientRequest before it was even delivered
to the receiver, leaving a dangling pointer.

Change-Id: I8972795d166fa46dd736005dd4df33b9a7ea2463
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Bernd Weimer <bernd.weimer@qt.io>
(cherry picked from commit bb186192373c6ff796c9084f22d48b02d14886c7)

3 files changed, 16 insertions, 4 deletions

diff --git a/src/intent-client-lib/intentclient.cpp b/src/intent-client-lib/intentclient.cpp
index bbd483a7..17e91eae 100644
--- a/src/intent-client-lib/intentclient.cpp
+++ b/src/intent-client-lib/intentclient.cpp
@@ -123,6 +123,7 @@ IntentClient::IntentClient(IntentClientSystemInterface *systemInterface, QObject
     : QObject(parent)
     , m_systemInterface(systemInterface)
 {
+    m_lastWaitingCleanup.start();
     m_systemInterface->setParent(this);
 }
 
@@ -237,11 +238,11 @@ void IntentClient::replyFromSystem(const QUuid &requestId, bool error, const QVa
 {
     IntentClientRequest *icr = nullptr;
     auto it = std::find_if(m_waiting.begin(), m_waiting.end(),
-                           [requestId](IntentClientRequest *ir) -> bool {
-            return (ir->requestId() == requestId);
+                           [requestId](const QPointer<IntentClientRequest> &ir) -> bool {
+            return ir && (ir->requestId() == requestId);
     });
 
-    if (it == m_waiting.cend()) {
+    if (it == m_waiting.end()) {
         qCWarning(LogIntents) << "IntentClient received an unexpected intent reply for request"
                               << requestId << " succeeded:" << !error << "error:"
                               << result.value(qL1S("errorMessage")).toString() << "result:" << result;
@@ -250,6 +251,12 @@ void IntentClient::replyFromSystem(const QUuid &requestId, bool error, const QVa
     icr = *it;
     m_waiting.erase(it);
 
+    // make sure to periodically remove all requests that were gc'ed before a reply was received
+    if (m_lastWaitingCleanup.elapsed() > 1000) {
+        m_waiting.removeAll({ });
+        m_lastWaitingCleanup.start();
+    }
+
     if (error)
         icr->setErrorMessage(result.value(qSL("errorMessage")).toString());
     else
diff --git a/src/intent-client-lib/intentclient.h b/src/intent-client-lib/intentclient.h
index 54bbf24a..d03f92ce 100644
--- a/src/intent-client-lib/intentclient.h
+++ b/src/intent-client-lib/intentclient.h
@@ -49,6 +49,7 @@
 #include <QList>
 #include <QMap>
 #include <QPair>
+#include <QElapsedTimer>
 
 #include <QtAppManCommon/global.h>
 
@@ -100,7 +101,8 @@ private:
     Q_DISABLE_COPY(IntentClient)
     static IntentClient *s_instance;
 
-    QList<IntentClientRequest *> m_waiting;
+    QList<QPointer<IntentClientRequest>> m_waiting;
+    QElapsedTimer m_lastWaitingCleanup;
     QMap<QPair<QString, QString>, IntentHandler *> m_handlers; // intentId + appId -> handler
 
     // no timeouts by default -- these have to be set at runtime
diff --git a/src/manager-lib/intentaminterface.cpp b/src/manager-lib/intentaminterface.cpp
index 1b8f447c..b704082b 100644
--- a/src/manager-lib/intentaminterface.cpp
+++ b/src/manager-lib/intentaminterface.cpp
@@ -313,6 +313,9 @@ void IntentClientAMImplementation::requestToSystem(QPointer<IntentClientRequest>
     // on app startup and (b) have consistent behavior in single- and multi-process mode
 
     QMetaObject::invokeMethod(m_ic, [icr, this]() {
+        if (!icr)
+            return;
+
         IntentServerRequest *isr = m_issi->requestToSystem(icr->requestingApplicationId(), icr->intentId(),
                                                            icr->applicationId(), icr->parameters());
         QUuid requestId = isr ? isr->requestId() : QUuid();