Method loadPythonScript

Engine/AppInstance.cpp:705–819

} // AppInstance::load

bool
AppInstance::loadPythonScript(const QFileInfo& file)
{
    std::string addToPythonPath("sys.path.append(\"");

    addToPythonPath += file.path().toStdString();
    addToPythonPath += "\")\n";

    std::string err;
    bool ok  = NATRON_PYTHON_NAMESPACE::interpretPythonScript(addToPythonPath, &err, 0);
    assert(ok);
    if (!ok) {
        throw std::runtime_error("AppInstance::loadPythonScript(" + file.path().toStdString() + "): interpretPythonScript(" + addToPythonPath + " failed!");
    }

    std::string s = "app = app1\n";
    ok = NATRON_PYTHON_NAMESPACE::interpretPythonScript(s, &err, 0);
    assert(ok);
    if (!ok) {
        throw std::runtime_error("AppInstance::loadPythonScript(" + file.path().toStdString() + "): interpretPythonScript(" + s + " failed!");
    }

    QFile f( file.absoluteFilePath() );
    if ( !f.open(QIODevice::ReadOnly) ) {
        return false;
    }
    QTextStream ts(&f);
    QString content = ts.readAll();
    bool hasCreateInstance = content.contains( QString::fromUtf8("def createInstance") );
    /*
       The old way of doing it was

        QString hasCreateInstanceScript = QString("import sys\n"
        "import %1\n"
        "ret = True\n"
        "if not hasattr(%1,\"createInstance\") or not hasattr(%1.createInstance,\"__call__\"):\n"
        "    ret = False\n").arg(filename);


        ok = interpretPythonScript(hasCreateInstanceScript.toStdString(), &err, 0);


       which is wrong because it will try to import the script first.
       But we in the case of regular scripts, we allow the user to access externally declared variables such as "app", "app1" etc...
       and this would not be possible if the script was imported. Importing the module would then fail because it could not
       find the variables and the script could not be executed.
     */

    if (hasCreateInstance) {
        QString moduleName = file.fileName();
        int lastDotPos = moduleName.lastIndexOf( QChar::fromLatin1('.') );
        if (lastDotPos != -1) {
            moduleName = moduleName.left(lastDotPos);
        }

        std::stringstream ss;
        ss << "import " << moduleName.toStdString() << '\n';
        ss << moduleName.toStdString() << ".createInstance(app,app)";