Qt Reference Documentation

# main.cpp Example File

script/qscript/main.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
     **     the names of its contributors may be used to endorse or promote
     **     products derived from this software without specific prior written
     **     permission.
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include <qscriptengine.h>

     #include <QtCore/QFile>
     #include <QtCore/QTextStream>
     #include <QtCore/QStringList>
     #include <QtGui/QApplication>

     #include <stdlib.h>

     #include "bytearrayclass.h"

     static bool wantsToQuit;

     static QScriptValue qtscript_quit(QScriptContext *ctx, QScriptEngine *eng)
     {
         Q_UNUSED(ctx);
         wantsToQuit = true;
         return eng->undefinedValue();
     }

     static void interactive(QScriptEngine *eng)
     {
         QScriptValue global = eng->globalObject();
         QScriptValue quitFunction = eng->newFunction(qtscript_quit);
         if (!global.property(QLatin1String("exit")).isValid())
             global.setProperty(QLatin1String("exit"), quitFunction);
         if (!global.property(QLatin1String("quit")).isValid())
             global.setProperty(QLatin1String("quit"), quitFunction);
         wantsToQuit = false;

         QTextStream qin(stdin, QFile::ReadOnly);

         const char *qscript_prompt = "qs> ";
         const char *dot_prompt = ".... ";
         const char *prompt = qscript_prompt;

         QString code;

         forever {
             QString line;

             printf("%s", prompt);
             fflush(stdout);

             line = qin.readLine();
             if (line.isNull())
                 break;

             code += line;
             code += QLatin1Char('\n');

             if (line.trimmed().isEmpty()) {
                 continue;

             } else if (! eng->canEvaluate(code)) {
                 prompt = dot_prompt;

             } else {
                 QScriptValue result = eng->evaluate(code, QLatin1String("typein"));

                 code.clear();
                 prompt = qscript_prompt;

                 if (! result.isUndefined())
                     fprintf(stderr, "%s\n", qPrintable(result.toString()));

                 if (wantsToQuit)
                     break;
             }
         }
     }

     static QScriptValue importExtension(QScriptContext *context, QScriptEngine *engine)
     {
         return engine->importExtension(context->argument(0).toString());
     }

     static QScriptValue loadScripts(QScriptContext *context, QScriptEngine *engine)
     {
         for (int i = 0; i < context->argumentCount(); ++i) {
             QString fileName = context->argument(0).toString();
             QFile file(fileName);
             if (!file.open(QIODevice::ReadOnly))
                 return context->throwError(QString::fromLatin1("could not open %0 for reading").arg(fileName));
             QTextStream ts(&file);
             QString contents = ts.readAll();
             file.close();
             QScriptContext *pc = context->parentContext();
             context->setActivationObject(pc->activationObject());
             context->setThisObject(pc->thisObject());
             QScriptValue ret = engine->evaluate(contents);
             if (engine->hasUncaughtException())
                 return ret;
         }
         return engine->undefinedValue();
     }

     int main(int argc, char *argv[])
     {
         QApplication *app;
         if (argc >= 2 && !qstrcmp(argv[1], "-tty")) {
             ++argv;
            --argc;
             app = new QApplication(argc, argv, QApplication::Tty);
         } else {
             app = new QApplication(argc, argv);
         }

         QScriptEngine *eng = new QScriptEngine();

         QScriptValue globalObject = eng->globalObject();

         globalObject.setProperty("load", eng->newFunction(loadScripts, /*length=*/1));

         {
             if (!globalObject.property("qt").isObject())
                 globalObject.setProperty("qt", eng->newObject());
             QScriptValue qscript = eng->newObject();
             qscript.setProperty("importExtension", eng->newFunction(importExtension));
             globalObject.property("qt").setProperty("script", qscript);
         }

         ByteArrayClass *byteArrayClass = new ByteArrayClass(eng);
         globalObject.setProperty("ByteArray", byteArrayClass->constructor());

         if (! *++argv) {
             interactive(eng);
             return EXIT_SUCCESS;
         }

         while (const char *arg = *argv++) {
             QString fn = QString::fromLocal8Bit(arg);

             if (fn == QLatin1String("-i")) {
                 interactive(eng);
                 break;
             }

             QString contents;
             int lineNumber = 1;

             if (fn == QLatin1String("-")) {
                 QTextStream stream(stdin, QFile::ReadOnly);
                 contents = stream.readAll();
             }

             else {
                 QFile file(fn);

                 if (file.open(QFile::ReadOnly)) {
                     QTextStream stream(&file);
                     contents = stream.readAll();
                     file.close();

                     // strip off #!/usr/bin/env qscript line
                     if (contents.startsWith("#!")) {
                         contents.remove(0, contents.indexOf("\n"));
                         ++lineNumber;
                     }
                 }
             }

             if (contents.isEmpty())
                 continue;

             QScriptValue r = eng->evaluate(contents, fn, lineNumber);
             if (eng->hasUncaughtException()) {
                 QStringList backtrace = eng->uncaughtExceptionBacktrace();
                 fprintf (stderr, "    %s\n%s\n\n", qPrintable(r.toString()),
                          qPrintable(backtrace.join("\n")));
                 return EXIT_FAILURE;
             }
         }

         delete eng;
         delete app;

         return EXIT_SUCCESS;
     }