add exceptionhandler code for connected signals/JS methods

- there wasn't any error information if a C++ triggered signal resulted
   in a JS method which has an error, now it will create an exception for it
 - creating messagebox inside the lib is something what we want to avoid,
   so the developer itself is responsible to catch these exceptions
 - most cases of the installer code does that already

Change-Id: I07486f73be9de13a486de235f14e3a7d7b54f5b1
Reviewed-by: Karsten Heimrich <karsten.heimrich@digia.com>

src/libs/installer/scriptengine.cpp

@@ -209,6 +209,8 @@ ScriptEngine::ScriptEngine(PackageManagerCore *core)
 
     globalObject().property(QLatin1String("installer"))
         .setProperty(QLatin1String("components"), scriptComponentsObject);
+
+    connect(this, SIGNAL(signalHandlerException(QScriptValue)), SLOT(handleException(QScriptValue)));
 }
 
 ScriptEngine::~ScriptEngine()
@@ -279,6 +281,12 @@ QScriptValue ScriptEngine::loadInConext(const QString &context, const QString &f
     return scriptContext;
 }
 
+void ScriptEngine::handleException(const QScriptValue &value)
+{
+    if (!value.engine())
+        return;
+    throw Error(uncaughtExceptionString(this, tr("Fatal error while evaluating a script.")));
+}
 
 /*!
     Tries to call the method with \a name within the script and returns the result. If the method

src/libs/installer/scriptengine.h

@@ -71,11 +71,12 @@ public:
     explicit ScriptEngine(PackageManagerCore *core);
     ~ScriptEngine();
     void setGuiQObject(QObject *guiQObject);
-    QScriptValue callScriptMethod(const QScriptValue &scriptContext, const QString &name,
-        const QScriptValueList &parameters = QScriptValueList()) const;
+    QScriptValue callScriptMethod(const QScriptValue &scriptContext, const QString &methodName,
+        const QScriptValueList &arguments = QScriptValueList()) const;
 
     QScriptValue loadInConext(const QString &context, const QString &fileName, const QString &scriptInjection = QString());
-
+private slots:
+    void handleException(const QScriptValue &value);
 private:
     QScriptValue generateMessageBoxObject();
     QScriptValue generateDesktopServicesObject();

tests/auto/installer/scriptengine/data/broken_connect.qs

@@ -0,0 +1,11 @@
+function BrokenConnect()
+{
+    emiter.emitted.connect(receive)
+}
+
+function receive()
+{
+    print("function receive()");
+    // this should throw an exception, "foo" does not exist
+    foo.bar = "test";
+}

tests/auto/installer/scriptengine/scriptengine.qrc

@@ -3,5 +3,6 @@
         <file>data/auto-install.qs</file>
         <file>data/component1.qs</file>
         <file>data/component2.qs</file>
+        <file>data/broken_connect.qs</file>
     </qresource>
 </RCC>

tests/auto/installer/scriptengine/tst_scriptengine.cpp

@@ -11,8 +11,6 @@
 
 using namespace QInstaller;
 
-// -- InstallerGui
-
 class TestGui : public QInstaller::PackageManagerGui
 {
     Q_OBJECT
@@ -34,6 +32,18 @@ public:
     }
 };
 
+class EmitSignalObject : public QObject
+{
+    Q_OBJECT
+
+public:
+    EmitSignalObject() {}
+    ~EmitSignalObject() {}
+    void produceSignal() { emit emitted(); }
+signals:
+    void emitted();
+};
+
 
 class tst_ScriptEngine : public QObject
 {
@@ -54,6 +64,42 @@ private slots:
         m_scriptEngine = m_core.scriptEngine();
     }
 
+    void testBrokenJSMethodConnect()
+    {
+        EmitSignalObject emiter;
+        m_scriptEngine->globalObject().setProperty(QLatin1String("emiter"),
+            m_scriptEngine->newQObject(&emiter));
+
+        QScriptValue context = m_scriptEngine->loadInConext(QLatin1String("BrokenConnect"),
+            ":///data/broken_connect.qs");
+
+        QVERIFY(context.isValid());
+
+        if (m_scriptEngine->hasUncaughtException()) {
+            QFAIL(qPrintable(QString::fromLatin1("ScriptEngine hasUncaughtException:\n %1").arg(
+                uncaughtExceptionString(m_scriptEngine))));
+        }
+
+        const QString debugMesssage(
+            "create Error-Exception: \"Fatal error while evaluating a script.\n\n"
+            "ReferenceError: Can't find variable: foo\n\n"
+            "Backtrace:\n"
+#if QT_VERSION < 0x050000
+                "\t<anonymous>()@:///data/broken_connect.qs:10\" ");
+#else
+            "\treceive() at :///data/broken_connect.qs:10\n"
+            "\t<global>() at -1\" ");
+#endif
+        try {
+            // ignore Output from script
+            setExpectedScriptOutput("function receive()");
+            setExpectedScriptOutput(qPrintable(debugMesssage));
+            emiter.produceSignal();
+        } catch (const Error &error) {
+            QVERIFY2(debugMesssage.contains(error.message()), "There was some unexpected error.");
+        }
+    }
+
     void testScriptPrint()
     {
         setExpectedScriptOutput("test");
@@ -199,7 +245,7 @@ private:
 
     PackageManagerCore m_core;
     Component *m_component;
-    QScriptEngine *m_scriptEngine;
+    ScriptEngine *m_scriptEngine;
 
 };