JUCE/modules/juce_javascript/javascript/juce_JavascriptEngine.cpp

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

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

   JUCE is an open source framework subject to commercial or open source
   licensing.

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   JUCE framework with any other source code, object code, content or any other
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   Or:

   You may also use this code under the terms of the AGPLv3:
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   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.

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

namespace juce
{

//==============================================================================
class JavascriptEngine::Impl
{
public:
    using ValuePtr = detail::qjs::QuickJSContext::ValuePtr;

    //==============================================================================
    explicit Impl (const RelativeTime* maximumExecutionTimeIn)
        : engine (std::make_unique<detail::QuickJSWrapper> (maximumExecutionTimeIn))
    {
        detail::DynamicObjectWrapper::createClass (engine->getQuickJSRuntime());
    }

    void registerNativeObject (const Identifier& name,
                               DynamicObject::Ptr dynamicObject,
                               std::optional<detail::qjs::JSValue> parent = std::nullopt)
    {
        auto wrapper  = std::make_unique<detail::DynamicObjectWrapper> (*engine, dynamicObject);
        auto* ctx     = engine->getQuickJSContext();
        auto jsObject = JS_NewObjectClass (ctx, (int) detail::DynamicObjectWrapper::getClassId());
        detail::qjs::JS_SetOpaque (jsObject, (void*) wrapper.get());

        std::vector<detail::qjs::JSCFunctionListEntry> propertyFunctionList;

        for (const auto& [identifier, prop] : wrapper->getProperties())
        {
            auto* jsIdentifier = identifier.toString().toRawUTF8();

            if (prop.isMethod())
            {
                detail::qjs::JS_SetPropertyStr (ctx,
                                                jsObject,
                                                jsIdentifier,
                                                JS_NewCFunctionMagic (ctx,
                                                                      detail::DynamicObjectWrapper::callDispatcher,
                                                                      jsIdentifier,
                                                                      0,
                                                                      detail::qjs::JS_CFUNC_generic_magic,
                                                                      wrapper->getOrdinal (identifier)));
            }
            else if (prop.isObject())
            {
                if (auto* embeddedObject = prop.getDynamicObject())
                    registerNativeObject (identifier, embeddedObject, jsObject);
            }
            else
            {
                const auto entry = detail::makeFunctionListEntry (jsIdentifier,
                                                                  detail::DynamicObjectWrapper::getDispatcher,
                                                                  detail::DynamicObjectWrapper::setDispatcher,
                                                                  wrapper->getOrdinal (identifier));
                propertyFunctionList.push_back (entry);
            }
        }

        if (! propertyFunctionList.empty())
        {
            detail::qjs::JS_SetPropertyFunctionList (ctx,
                                             jsObject,
                                             propertyFunctionList.data(),
                                             (int) propertyFunctionList.size());
        }

        const auto jsObjectName = name.toString().toRawUTF8();

        if (parent.has_value())
        {
            detail::qjs::JS_SetPropertyStr (ctx, *parent, jsObjectName, jsObject);
        }
        else
        {
            ValuePtr globalObject { detail::qjs::JS_GetGlobalObject (ctx), ctx };
            detail::qjs::JS_SetPropertyStr (ctx, globalObject.get(), jsObjectName, jsObject);
        }

        wrapper.release();
    }

    var evaluate (const String& code, Result* errorMessage)
    {
        engine->resetTimeout();

        if (errorMessage != nullptr)
            *errorMessage = Result::ok();

        const auto result = detail::quickJSToJuce ({ JS_Eval (engine->getQuickJSContext(),
                                                              code.toRawUTF8(),
                                                              code.getNumBytesAsUTF8(),
                                                              "",
                                                              JS_EVAL_TYPE_GLOBAL),
                                                     engine->getQuickJSContext() });

        if (auto* v = std::get_if<var> (&result))
            return *v;

        if (auto* e = std::get_if<String> (&result))
            if (errorMessage != nullptr)
                *errorMessage = Result::fail (*e);

        return var::undefined();
    }

    Result execute (const String& code)
    {
        auto result = Result::ok();
        evaluate (code, &result);
        return result;
    }

    var callFunction (const Identifier& function,
                      const var::NativeFunctionArgs& args,
                      Result* errorMessage)
    {
        engine->resetTimeout();

        auto* ctx = engine->getQuickJSContext();
        const auto functionStr = function.toString();

        const auto fn = detail::qjs::JS_NewAtomLen (ctx, functionStr.toRawUTF8(), functionStr.getNumBytesAsUTF8());

        detail::JSFunctionArguments argList { ctx, args };

        detail::qjs::QuickJSContext::ValuePtr global { JS_GetGlobalObject (ctx), ctx };
        detail::qjs::QuickJSContext::ValuePtr returnVal { JS_Invoke (ctx, global.get(), fn, argList.getSize(), argList.getArguments()), ctx };

        JS_FreeAtom (ctx, fn);

        if (errorMessage != nullptr)
            *errorMessage = Result::ok();

        const auto result = detail::quickJSToJuce (returnVal);

        if (auto* v = std::get_if<var> (&result))
            return *v;

        if (auto* e = std::get_if<String> (&result))
            if (errorMessage != nullptr)
                *errorMessage = Result::fail (*e);

        return var::undefined();
    }

    void stop() noexcept
    {
        engine->stop();
    }

    JSObject getRootObject() const
    {
        return JSObject { engine.get() };
    }

private:
    std::unique_ptr<detail::QuickJSWrapper> engine;
};

//==============================================================================
JavascriptEngine::JavascriptEngine()
    : maximumExecutionTime (15.0),
      impl (std::make_unique<Impl> (&maximumExecutionTime))
{
}

JavascriptEngine::~JavascriptEngine() = default;

void JavascriptEngine::registerNativeObject (const Identifier& name, DynamicObject* object)
{
    impl->registerNativeObject (name, object);
}

Result JavascriptEngine::execute (const String& javascriptCode)
{
    return impl->execute (javascriptCode);
}

var JavascriptEngine::evaluate (const String& javascriptCode, Result* errorMessage)
{
    return impl->evaluate (javascriptCode, errorMessage);
}

var JavascriptEngine::callFunction (const Identifier& function,
                                    const var::NativeFunctionArgs& args,
                                    Result* errorMessage)
{
    return impl->callFunction (function, args, errorMessage);
}

void JavascriptEngine::stop() noexcept
{
    impl->stop();
}

JSObject JavascriptEngine::getRootObject() const
{
    return impl->getRootObject();
}

NamedValueSet JavascriptEngine::getRootObjectProperties() const
{
    return getRootObject().getProperties();
}

} // namespace juce