commandlineparser: Make it possible to load dummydata like qmlscene

The code is copied over from qmlscene.

.gitignore

@@ -0,0 +1,2 @@
+/build/
+/compile_commands.json

src/commandline/commandlineparser.cpp

@@ -5,6 +5,7 @@
 #include <QtCore/QJsonDocument>
 #include <QtCore/QJsonArray>
 #include <QtCore/QJsonObject>
+#include <QtQml/QQmlContext>
 
 #include <utility>
 
@@ -72,6 +73,33 @@ void CommandLineParser::setEngine(QQmlEngine* engine)
     }
 }
 
+void CommandLineParser::loadDummyData(QQmlEngine *engine)
+{
+    const QFileInfo file = ProvidesSomething::self()->filePath().toLocalFile();
+    const QString pathToQml = file.canonicalPath();
+
+    const QDir dir(pathToQml + "/dummydata/", "*.qml");
+    QStringList list = dir.entryList();
+    for (int i = 0; i < list.size(); ++i) {
+        QString qml = list.at(i);
+        QQmlComponent comp(engine, dir.filePath(qml));
+        QObject *dummyData = comp.create();
+
+        if(comp.isError()) {
+            const QList<QQmlError> errors = comp.errors();
+            for (const QQmlError &error : errors)
+                fprintf(stderr, "%s\n", qPrintable(error.toString()));
+        }
+
+        if (dummyData) {
+            fprintf(stderr, "Loaded dummy data: %s\n", qPrintable(dir.filePath(qml)));
+            qml.truncate(qml.length()-4);
+            engine->rootContext()->setContextProperty(qml, dummyData);
+            dummyData->setParent(engine);
+        }
+    }
+}
+
 void CommandLineParser::printHelp()
 {
     for (auto& optionStruct : std::as_const(_optionsStruct)) {

src/commandline/commandlineparser.h

@@ -46,6 +46,8 @@ class CommandLineParser : public QCommandLineParser {
      */
     void setApplication(QCoreApplication* application);
 
+    void loadDummyData(QQmlEngine *engine);
+
 private:
     struct OptionStruct {
         QCommandLineOption option;

src/main.cpp

@@ -33,6 +33,7 @@ int main(int argc, char *argv[])
             ProvidesSomething::self()->setFilePath(QUrl::fromUserInput(dir.absolutePath()));
         }
     }
+    commandLineParser.loadDummyData(&appEngine);
 
     return app.exec();
 }