JUCE/examples/Utilities/JavaScriptDemo.h

/*
  ==============================================================================

   This file is part of the JUCE examples.
   Copyright (c) 2020 - Raw Material Software Limited

   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.

   THE SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES,
   WHETHER EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR
   PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

/*******************************************************************************
 The block below describes the properties of this PIP. A PIP is a short snippet
 of code that can be read by the Projucer and used to generate a JUCE project.

 BEGIN_JUCE_PIP_METADATA

 name:             JavaScriptDemo
 version:          1.0.0
 vendor:           JUCE
 website:          http://juce.com
 description:      Showcases JavaScript features.

 dependencies:     juce_core, juce_data_structures, juce_events, juce_graphics,
                   juce_gui_basics, juce_gui_extra
 exporters:        xcode_mac, vs2019, linux_make, androidstudio, xcode_iphone

 moduleFlags:      JUCE_STRICT_REFCOUNTEDPOINTER=1

 type:             Component
 mainClass:        JavaScriptDemo

 useLocalCopy:     1

 END_JUCE_PIP_METADATA

*******************************************************************************/

#pragma once

#include "../Assets/DemoUtilities.h"

//==============================================================================
class JavaScriptDemo    : public Component,
                          private CodeDocument::Listener,
                          private Timer
{
public:
    JavaScriptDemo()
    {
        setOpaque (true);

        editor.reset (new CodeEditorComponent (codeDocument, nullptr));
        addAndMakeVisible (editor.get());
        editor->setFont ({ Font::getDefaultMonospacedFontName(), 14.0f, Font::plain });
        editor->setTabSize (4, true);

        outputDisplay.setMultiLine (true);
        outputDisplay.setReadOnly (true);
        outputDisplay.setCaretVisible (false);
        outputDisplay.setFont ({ Font::getDefaultMonospacedFontName(), 14.0f, Font::plain });
        addAndMakeVisible (outputDisplay);

        codeDocument.addListener (this);

        editor->loadContent (
            "/*\n"
            "    Javascript! In this simple demo, the native\n"
            "    code provides an object called \'Demo\' which\n"
            "    has a method \'print\' that writes to the\n"
            "    console below...\n"
            "*/\n"
            "\n"
            "Demo.print (\"Hello World in JUCE + Javascript!\");\n"
            "Demo.print (\"\");\n"
            "\n"
            "function factorial (n)\n"
            "{\n"
            "    var total = 1;\n"
            "    while (n > 0)\n"
            "        total = total * n--;\n"
            "    return total;\n"
            "}\n"
            "\n"
            "for (var i = 1; i < 10; ++i)\n"
            "    Demo.print (\"Factorial of \" + i \n"
            "                   + \" = \" + factorial (i));\n");

        setSize (600, 750);
    }

    void runScript()
    {
        outputDisplay.clear();

        JavascriptEngine engine;
        engine.maximumExecutionTime = RelativeTime::seconds (5);
        engine.registerNativeObject ("Demo", new DemoClass (*this));

        auto startTime = Time::getMillisecondCounterHiRes();

        auto result = engine.execute (codeDocument.getAllContent());

        auto elapsedMs = Time::getMillisecondCounterHiRes() - startTime;

        if (result.failed())
            outputDisplay.setText (result.getErrorMessage());
        else
            outputDisplay.insertTextAtCaret ("\n(Execution time: " + String (elapsedMs, 2) + " milliseconds)");
    }

    void consoleOutput (const String& message)
    {
        outputDisplay.moveCaretToEnd();
        outputDisplay.insertTextAtCaret (message + newLine);
    }

    //==============================================================================
    // This class is used by the script, and provides methods that the JS can call.
    struct DemoClass  : public DynamicObject
    {
        DemoClass (JavaScriptDemo& demo) : owner (demo)
        {
            setMethod ("print", print);
        }

        static Identifier getClassName()    { return "Demo"; }

        static var print (const var::NativeFunctionArgs& args)
        {
            if (args.numArguments > 0)
                if (auto* thisObject = dynamic_cast<DemoClass*> (args.thisObject.getObject()))
                    thisObject->owner.consoleOutput (args.arguments[0].toString());

            return var::undefined();
        }

        JavaScriptDemo& owner;

        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (DemoClass)
    };


    void paint (Graphics& g) override
    {
        g.fillAll (getUIColourIfAvailable (LookAndFeel_V4::ColourScheme::UIColour::windowBackground));
    }

private:
    CodeDocument codeDocument;
    std::unique_ptr<CodeEditorComponent> editor;
    TextEditor outputDisplay;

    void codeDocumentTextInserted (const String&, int) override    { startTimer (300); }
    void codeDocumentTextDeleted (int, int) override               { startTimer (300); }

    void timerCallback() override
    {
        stopTimer();
        runScript();
    }

    void resized() override
    {
        auto r = getLocalBounds().reduced (8);

        editor->setBounds       (r.removeFromTop (proportionOfHeight (0.6f)));
        outputDisplay.setBounds (r.withTrimmedTop (8));
    }

    void lookAndFeelChanged() override
    {
        outputDisplay.applyFontToAllText (outputDisplay.getFont());
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (JavaScriptDemo)
};