I am currently working on optimizing the operations of QScriptEngine within one of my functions.
The function, called executeCustomJSOperation, is responsible for executing the same JS code across multiple files. Each file requires a modification to a global variable called $xmlData. Essentially, this function loads an XML file into memory using the $xmlData variable and then applies the same JavaScript code (jsString) to edit the XML file using JavaScript. Finally, the $xmlData variable is updated with the edited XML content.
I managed to achieve a 2.5 speedup by implementing an OpenMP parallel for loop over the XML files processing. However, I am now looking for ways to further enhance the speed of this function.
Below is the code snippet:
// This function allows users to echo JavaScript variables for debugging purposes through cout
QScriptValue echo(QScriptContext *context, QScriptEngine *engine)
{
std::cout << context->argument(0).toString().toUtf8().constData() << std::endl;
return "";
}
void executeCustomJSOperation(const QString &jsString, const QStringList &filesToProcess){
QString rexmlString, jsxmlString;
QFile rexmlfile(":/resources/libs/rexml.js"); // loading JavaScript libraries as strings into memory
QFile jsxmlfile(":/resources/libs/jsxml.js");
rexmlfile.open(QFile::ReadOnly | QFile::Text);
jsxmlfile.open(QFile::ReadOnly | QFile::Text);
rexmlString=QTextStream(&rexmlfile).readAll();
jsxmlString=QTextStream(&jsxmlfile).readAll();
// Processing all XmlFiles
#pragma omp parallel for // Achieved 2.5 speedup on my machine
for(int i=0; i<filesToProcess.size(); i++){
QString currXmlFileString;
QScriptEngine engine;
QScriptValue engineResult;
// Adding echo function for user debugging
QScriptValue echoFunction = engine.newFunction(echo);
engine.globalObject().setProperty("echo", echoFunction);
engine.evaluate(rexmlString); // Loading JavaScript libraries in the JS engine
engine.evaluate(jsxmlString);
QFile currXmlFile(filesToProcess[i]);
currXmlFileString=QTextStream(&currXmlFile).readAll();
currXmlFile.close();
engine.globalObject().setProperty("$xmlData",currXmlFileString);
engine.evaluate("main(); function main() {"+jsString+"}"); // The main function allows the use of 'return' statement to exit from user code
engineResult=engine.globalObject().property("$xmlData");
QTextStream(&currXmlFile) << engineResult.toString(); // Retrieving modified XML by JavaScript and saving it back to the file
}
}
Are there any suggestions on how to further optimize this code? Feel free to ask if you have any questions.