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Thread: QtScript Bindings Generator ScriptShell Event Binding

  1. 16th March 2010, 14:44 #1
    JohannesMunk
    JohannesMunk is offline Advanced user
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    Default QtScript Bindings Generator ScriptShell Event Binding

    Hi there!

    How can I call the native event handler when using the scriptshell binding of the qt script binding generator?

    I'm using the splendid qt script binding generator lab-project to make all qt classes fully scriptable. Through the scriptshells it allows binding a script function to otherwise inaccessible protected event handlers. In non script you would derive from the class to access these..

    Qt Code: 
    1. scriptcode:
    2.  
    3. var a = new QWidget();
    4. a.setGeometry(50,50,200,100);
    5. a.show();
    6. a.event = function (event) {
    7.   print(event.type().toString());
    8. };
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    This works perfectly, but it hides the native implementation. If you look into the generated scriptshell files of the generator:

    Qt Code: 
    1. from: ..\com_trolltech_qt_gui\qtscriptshell_QWidget.cpp
    2.  
    3. bool  QtScriptShell_QWidget::event(QEvent*  arg__1)
    4. {
    5.     QScriptValue _q_function = __qtscript_self.property("event");
    6.     if (!_q_function.isFunction() || QTSCRIPT_IS_GENERATED_FUNCTION(_q_function)
    7.         || (__qtscript_self.propertyFlags("event") & QScriptValue::QObjectMember)) {
    8.         return QWidget::event(arg__1);
    9.     } else {
    10.         QScriptEngine *_q_engine = __qtscript_self.engine();
    11.         return qscriptvalue_cast<bool >(_q_function.call(__qtscript_self,
    12.             QScriptValueList()
    13.             << qScriptValueFromValue(_q_engine, arg__1)));
    14.     }
    15. }
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    So either the native or the script event handler is called. Now my question is, if I missed an obvious way to call the native event handler from script.

    If thats not possible I'm thinking of changing the scriptshell-generator-code (..\generator\shellimplgenerator.cpp ) to call the native handler for all events that have not been accepted inside the script-method. That's easy enough, but I want to know, if there is an out-of-the-box way.

    Thx!

    Johannes
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  2. 10th April 2010, 13:09 #2
    JohannesMunk
    JohannesMunk is offline Advanced user
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    Default Re: QtScript Bindings Generator ScriptShell Event Binding

    Hey there!

    Here is what I came up with:

    I changed the scriptshellgenerator code so that the generated code looks like this:

    Qt Code: 
    1. bool  QtScriptShell_QWidget::event(QEvent*  arg__1)
    2. {
    3.     QScriptValue _q_function = __qtscript_self.property("event");
    4.     if (!_q_function.isFunction() || QTSCRIPT_IS_GENERATED_FUNCTION(_q_function)
    5.         || (__qtscript_self.propertyFlags("event") & QScriptValue::QObjectMember)) {
    6.         return QWidget::event(arg__1);
    7.     } else {
    8.         QScriptEngine *_q_engine = __qtscript_self.engine();
    9.         // callmode. first bit: 1:callcpp|0:don't call cpp
    10.         // 2nd-bit: 1:returncpp|0:returnscript
    11.         int _callmode = 3;
    12.         QScriptValue _q_callmode = __qtscript_self.property("event_callmode");
    13.         if (_q_callmode.isValid()) _callmode = _q_callmode.toInt32();
    14.         if ((_callmode & 1) > 0) {
    15.             bool resultcpp = QWidget::event(arg__1);
    16.             bool resultscript = qscriptvalue_cast<bool >(_q_function.call(__qtscript_self,
    17.                 QScriptValueList()
    18.                 << qScriptValueFromValue(_q_engine, arg__1)));
    19.             if ((_callmode & 2) > 0) {
    20.                 return resultcpp;
    21.             } else {
    22.                 return resultscript;
    23.             }
    24.         } else {
    25.             return qscriptvalue_cast<bool >(_q_function.call(__qtscript_self,
    26.                 QScriptValueList()
    27.                 << qScriptValueFromValue(_q_engine, arg__1)));
    28.         }
    29.     }
    30. }
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    instead of the above.. So the default behaviour is to call both. And to return the value of the c++ implementation. If you want another behaviour, you need to specifiy a value for <eventname>_callmode.
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  3. 10th April 2010, 13:10 #3
    JohannesMunk
    JohannesMunk is offline Advanced user
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    Default Re: QtScript Bindings Generator ScriptShell Event Binding

    This is the ShellImplGenerator::write method in generator/shellimplgenerator.cpp which you need to change in the bindings generator.

    Qt Code: 
    1. void ShellImplGenerator::write(QTextStream &s, const  AbstractMetaClass *meta_class)
    2. {
    3.     if (FileOut::license)
    4.         writeQtScriptQtBindingsLicense(s);
    5.  
    6.     QString packName = meta_class->package().replace(".", "_");
    7.  
    8.     priGenerator->addSource(packName, fileNameForClass(meta_class));
    9.  
    10.     s << "#include \"qtscriptshell_" <<  meta_class->name() << ".h\"" << endl << endl;
    11.  
    12.     if (!meta_class->generateShellClass())
    13.         return;
    14.  
    15.     s << "#include <QtScript/QScriptEngine>" << endl;
    16.  
    17.     IncludeList list = meta_class->typeEntry()->extraIncludes();
    18.     qSort(list.begin(), list.end(), include_less_than);
    19.     foreach (const Include &inc, list) {
    20.         if (inc.type == Include::TargetLangImport)
    21.             continue;
    22.  
    23.         s << "#include ";
    24.         if (inc.type == Include::LocalPath)
    25.             s << "\"";
    26.         else
    27.             s << "<";
    28.  
    29.         s << inc.name;
    30.  
    31.         if (inc.type == Include::LocalPath)
    32.             s << "\"";
    33.         else
    34.             s << ">";
    35.  
    36.         s << endl;
    37.     }
    38.     s << endl;
    39.  
    40.     writeHelperCode(s, meta_class);
    41.  
    42.     // find constructors
    43.     AbstractMetaFunctionList ctors;
    44.     ctors =  meta_class->queryFunctions(AbstractMetaClass::Constructors
    45.                                        | AbstractMetaClass::WasVisible
    46.                                        |  AbstractMetaClass::NotRemovedFromTargetLang);
    47.     // find member functions
    48.     AbstractMetaFunctionList functions = meta_class->queryFunctions(
    49.         AbstractMetaClass:: VirtualFunctions |  AbstractMetaClass::WasVisible
    50.         | AbstractMetaClass::NotRemovedFromTargetLang
    51.         );
    52.  
    53.     // write metatype declarations
    54.     {
    55.         QSet<QString> registeredTypeNames =  m_qmetatype_declared_typenames;
    56.         declareFunctionMetaTypes(s, functions, registeredTypeNames);
    57.         s << endl;
    58.     }
    59.  
    60.     // write constructors
    61.     foreach (const AbstractMetaFunction *ctor, ctors) {
    62.         s << "QtScriptShell_" << meta_class->name()  << "::";
    63.         writeFunctionSignature(s, ctor, 0, QString(),  Option(OriginalName | ShowStatic));
    64.         s << endl;
    65.         s << "    : " << meta_class->qualifiedCppName()  << "(";
    66.         AbstractMetaArgumentList args = ctor->arguments();
    67.         for (int i = 0; i < args.size(); ++i) {
    68.             if (i > 0)
    69.                 s << ", ";
    70.             s << args.at(i)->argumentName();
    71.         }
    72.         s << ")" << " {}" << endl << endl;
    73.     }
    74.  
    75.     // write destructor
    76.     s << "QtScriptShell_" << meta_class->name() <<  "::"
    77.       << "~QtScriptShell_" << meta_class->name() <<  "()";
    78.     if (!meta_class->destructorException().isEmpty())
    79.         s << " " << meta_class->destructorException();
    80.     s << " {}" << endl << endl;
    81.  
    82.     // write member functions
    83.     for (int i = 0; i < functions.size(); ++i) {
    84.         AbstractMetaFunction *fun = functions.at(i);
    85.         writeFunctionSignature(s, fun, meta_class, QString(),
    86.                                Option(OriginalName | ShowStatic |  UnderscoreSpaces),
    87.                                "QtScriptShell_");
    88.         s << endl << "{" << endl;
    89.         QString scriptFunctionName = fun->name();
    90.         {
    91.             QPropertySpec *read = 0;
    92.             for (const AbstractMetaClass *cls = meta_class; !read  && cls; cls = cls->baseClass())
    93.                 read = cls->propertySpecForRead(fun->name());
    94.             if (read && (read->name() == fun->name())) {
    95.                 // use different name to avoid infinite recursion
    96.                 // ### not sure if this is the best solution though...
    97.                 scriptFunctionName.prepend("_qs_");
    98.             }
    99.         }
    100.  
    101.         s << "    QScriptValue _q_function =  __qtscript_self.property(\""
    102.           << scriptFunctionName << "\");" << endl;
    103.         s << "    if (!_q_function.isFunction() ||  QTSCRIPT_IS_GENERATED_FUNCTION(_q_function)" << endl
    104.           << "        || (__qtscript_self.propertyFlags(\""  << scriptFunctionName << "\") &  QScriptValue::QObjectMember)) {" << endl;
    105.  
    106.         AbstractMetaArgumentList args = fun->arguments();
    107.         s << "        ";
    108.         if (fun->isAbstract()) {
    109.             s << "qFatal(\"" << meta_class->name()  << "::" << fun->name()
    110.               << "() is abstract!\");" << endl;
    111.         } else {
    112.             // call the C++ implementation
    113.             if (fun->type()) {
    114.                 s << "return ";
    115.             }
    116.             s << meta_class->qualifiedCppName() << "::"  << fun->originalName() << "(";
    117.             for (int i = 0; i < args.size(); ++i) {
    118.                 if (i > 0)
    119.                     s << ", ";
    120.                 s << args.at(i)->argumentName();
    121.             }
    122.             s << ");" << endl;
    123.         }
    124.  
    125.         s << "    } else {" << endl;
    126.  
    127.         // call the script function
    128.         if (args.size() > 0)
    129.             s << "        QScriptEngine *_q_engine =  __qtscript_self.engine();" << endl;
    130.  
    131.         // NTS Addon
    132.         if (!fun->isAbstract()) {
    133.             s << "        // callmode. first bit:  1:callcpp|0:don't call cpp" << endl;
    134.             s << "        // 2nd-bit: 1:returncpp|0:returnscript"  << endl;
    135.             s << "        int _callmode = 3;" << endl;
    136.             s << "        QScriptValue _q_callmode =  __qtscript_self.property(\""
    137.               << scriptFunctionName << "_callmode\");"  << endl;
    138.             s << "        if (_q_callmode.isValid()) _callmode =  _q_callmode.toInt32();" << endl;
    139.             s << "        if ((_callmode & 1) > 0) {"  << endl;
    140.  
    141.             // First call the c++ implementation
    142.             s << "            ";
    143.                 if (fun->type()) {
    144.                     writeTypeInfo(s, fun->type());
    145.                     s << "resultcpp = ";
    146.                 }
    147.                 s << meta_class->qualifiedCppName() <<  "::" << fun->originalName() << "(";
    148.                 for (int i = 0; i < args.size(); ++i) {
    149.                     if (i > 0)
    150.                         s << ", ";
    151.                     s << args.at(i)->argumentName();
    152.                 }
    153.                 s << ");" << endl;
    154.  
    155.             // Then call the script implementation
    156.             s << "            ";
    157.             if (fun->type()) {
    158.                 writeTypeInfo(s, fun->type());
    159.                 s << "resultscript = qscriptvalue_cast<";
    160.                 writeTypeInfo(s, fun->type());
    161.                 s << ">(";
    162.             }
    163.             s << "_q_function.call(__qtscript_self";
    164.             if (args.size() > 0) {
    165.                 s << "," << endl;
    166.                 s << "                QScriptValueList()";
    167.                 int i = 0;
    168.                 for (int j = 0; j < args.size(); ++j) {
    169.                     if (fun->argumentRemoved(j+1))
    170.                         continue;
    171.                     s << endl << "                <<  ";
    172.                     s << "qScriptValueFromValue(_q_engine, ";
    173.                     AbstractMetaType *atype = args.at(j)->type();
    174.                     QString asig = atype->cppSignature();
    175.                     bool constCastArg = asig.endsWith('*') &&  asig.startsWith("const ");
    176.                     if (constCastArg)
    177.                         s << "const_cast<" << asig.mid(6)  << ">(";
    178.                     s << args.at(i)->argumentName() <<  ")";
    179.                     if (constCastArg)
    180.                         s << ")";
    181.                     ++i;
    182.                 }
    183.             }
    184.             s << ")";
    185.             if (fun->type())
    186.                 s << ")";
    187.             s << ";" << endl;
    188.  
    189.             if (fun->type()) {
    190.             // Decide which value to return
    191.             s << "            if ((_callmode & 2) > 0) {"  << endl;
    192.             s << "                return resultcpp;" <<  endl;
    193.             s << "            } else {" << endl;
    194.             s << "                return resultscript;" <<  endl;
    195.             s << "            }"<< endl;
    196.             }
    197.  
    198.             s << "        } else {" << endl;
    199.         }
    200.  
    201.         // only call the script implementation
    202.         s << "            ";
    203.         if (fun->type()) {
    204.             s << "return qscriptvalue_cast<";
    205.             writeTypeInfo(s, fun->type());
    206.             s << ">(";
    207.         }
    208.         s << "_q_function.call(__qtscript_self";
    209.         if (args.size() > 0) {
    210.             s << "," << endl;
    211.             s << "                QScriptValueList()";
    212.             int i = 0;
    213.             for (int j = 0; j < args.size(); ++j) {
    214.                 if (fun->argumentRemoved(j+1))
    215.                     continue;
    216.                 s << endl << "                << ";
    217.                 s << "qScriptValueFromValue(_q_engine, ";
    218.                 AbstractMetaType *atype = args.at(j)->type();
    219.                 QString asig = atype->cppSignature();
    220.                 bool constCastArg = asig.endsWith('*') &&  asig.startsWith("const ");
    221.                 if (constCastArg)
    222.                     s << "const_cast<" << asig.mid(6)  << ">(";
    223.                 s << args.at(i)->argumentName() << ")";
    224.                 if (constCastArg)
    225.                     s << ")";
    226.                 ++i;
    227.             }
    228.         }
    229.         s << ")";
    230.         if (fun->type())
    231.             s << ")";
    232.         s << ";" << endl;
    233.  
    234.         if (!fun->isAbstract()) {
    235.             s << "        }" << endl;
    236.         }
    237.  
    238.         s << "    }" << endl;
    239.  
    240.         s << "}" << endl << endl;
    241.     }
    242. }
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    Cheers,

    Johannes
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