Removed the need for extra Symbian traps after QApp construction.

This was achieved by putting back the old trap handler after the S60
framework construction has finished.

Task:     QTBUG-4960
AutoTest: Included and passed
RevBy:    Shane Kearns

3 files changed, 78 insertions, 0 deletions

diff --git a/src/gui/kernel/qapplication_s60.cpp b/src/gui/kernel/qapplication_s60.cpp
index 689429e..30bf99a 100644
--- a/src/gui/kernel/qapplication_s60.cpp
+++ b/src/gui/kernel/qapplication_s60.cpp
@@ -1030,6 +1030,14 @@ QApplication::QApplication(QApplication::QS60MainApplicationFactory factory, int
 void qt_init(QApplicationPrivate * /* priv */, int)
 {
     if (!CCoeEnv::Static()) {
+        // The S60 framework creates a new trap handler which will render any existing traps
+        // invalid as long as it is active. This means that all code in main() that occurs after
+        // the QApplication construction needs to be surrounded by a new trap, despite having
+        // an outer one already. To avoid this, we save the original trap handler here, and set
+        // it back after the S60 framework is constructed. Then we restore it right before the S60
+        // framework destruction.
+        TTrapHandler *origTrapHandler = User::TrapHandler();
+
         // The S60 framework has not been initalized. We need to do it.
         TApaApplicationFactory factory(S60->s60ApplicationFactory ?
                 S60->s60ApplicationFactory : newS60Application);
@@ -1041,6 +1049,8 @@ void qt_init(QApplicationPrivate * /* priv */, int)
         QT_TRAP_THROWING(coe->ConstructAppFromCommandLineL(factory,*commandLine));
         delete commandLine;
 
+        S60->s60InstalledTrapHandler = User::SetTrapHandler(origTrapHandler);
+
         S60->qtOwnsS60Environment = true;
     } else {
         S60->qtOwnsS60Environment = false;
@@ -1195,6 +1205,9 @@ void qt_cleanup()
     S60->wsSession().SetPointerCursorMode(EPointerCursorNone);
 
     if (S60->qtOwnsS60Environment) {
+        // Restore the S60 framework trap handler. See qt_init().
+        User::SetTrapHandler(S60->s60InstalledTrapHandler);
+
         CEikonEnv* coe = CEikonEnv::Static();
         coe->PrepareToExit();
         // The CEikonEnv itself is destroyed in here.
diff --git a/src/gui/kernel/qt_s60_p.h b/src/gui/kernel/qt_s60_p.h
index e25bc81..789d89e 100644
--- a/src/gui/kernel/qt_s60_p.h
+++ b/src/gui/kernel/qt_s60_p.h
@@ -124,6 +124,8 @@ public:
     static inline CAknTitlePane* titlePane();
     static inline CAknContextPane* contextPane();
     static inline CEikButtonGroupContainer* buttonGroupContainer();
+
+    TTrapHandler *s60InstalledTrapHandler;
 #endif
 };
 
diff --git a/tests/auto/qapplication/tst_qapplication.cpp b/tests/auto/qapplication/tst_qapplication.cpp
index 97aa092..675e559 100644
--- a/tests/auto/qapplication/tst_qapplication.cpp
+++ b/tests/auto/qapplication/tst_qapplication.cpp
@@ -136,6 +136,9 @@ private slots:
     void windowsCommandLine();
 
     void touchEventPropagation();
+
+    void symbianNeedForTraps();
+    void symbianLeaveThroughMain();
 };
 
 class EventSpy : public QObject
@@ -2011,6 +2014,66 @@ void tst_QApplication::touchEventPropagation()
     }
 }
 
+#ifdef Q_OS_SYMBIAN
+class CBaseDummy : public CBase
+{
+public:
+    CBaseDummy(int *numDestroyed) : numDestroyed(numDestroyed)
+    {
+    }
+    ~CBaseDummy()
+    {
+        (*numDestroyed)++;
+    }
+
+private:
+    int *numDestroyed;
+};
+
+static void fakeMain(int *numDestroyed)
+{
+    // Push a few objects, just so that the cleanup stack has something to clean up.
+    CleanupStack::PushL(new (ELeave) CBaseDummy(numDestroyed));
+    int argc = 0;
+    QApplication app(argc, 0);
+    CleanupStack::PushL(new (ELeave) CBaseDummy(numDestroyed));
+
+    User::Leave(KErrGeneral); // Fake error
+}
+#endif
+
+void tst_QApplication::symbianNeedForTraps()
+{
+#ifndef Q_OS_SYMBIAN
+    QSKIP("This is a Symbian-only test", SkipAll);
+#else
+    int argc = 0;
+    QApplication app(argc, 0);
+    int numDestroyed = 0;
+
+    // This next part should not require a trap. If it does, the test will crash.
+    CleanupStack::PushL(new (ELeave) CBaseDummy(&numDestroyed));
+    CleanupStack::PopAndDestroy();
+
+    QCOMPARE(numDestroyed, 1);
+
+    // No other failure condition. The program will crash if it does not pass.
+#endif
+}
+
+void tst_QApplication::symbianLeaveThroughMain()
+{
+#ifndef Q_OS_SYMBIAN
+    QSKIP("This is a Symbian-only test", SkipAll);
+#else
+    int numDestroyed = 0;
+    TInt err;
+    TRAP(err, fakeMain(&numDestroyed));
+
+    QCOMPARE(numDestroyed, 2);
+#endif
+}
+
 //QTEST_APPLESS_MAIN(tst_QApplication)
 int main(int argc, char *argv[])
 {