////  JSAPIExample.cpp//  plugins/JSAPIExample/src////  Copyright (c) 2019-2020 humbletim (humbletim@gmail.com)//  Copyright (c) 2019 Kalila L. (kasenvr@gmail.com)////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html //  Example of prototyping new JS APIs by leveraging the existing plugin system. #include <QCoreApplication>#include <QtCore/QByteArray>#include <QtCore/QDir>#include <QtCore/QFileInfo>#include <QtCore/QJsonObject>#include <QtCore/QLoggingCategory>#include <QtCore/QThread>#include <QtCore/QTimer>#include <QtScript/QScriptEngine>#include <QtScript/QScriptable> #include <SettingHelpers.h>  // for ::settingsFilename()#include <SharedUtil.h>      // for usecTimestampNow()#include <shared/ScriptInitializerMixin.h> // NOTE: replace this with your own namespace when starting a new plugin (to avoid .so/.dll symbol clashes)namespace REPLACE_ME_WITH_UNIQUE_NAME { static constexpr auto JSAPI_SEMANTIC_VERSION = "0.0.1";static constexpr auto JSAPI_EXPORT_NAME = "JSAPIExample"; QLoggingCategory logger{ "jsapiexample" }; inline QVariant raiseScriptingError(QScriptContext* context, const QString& message, const QVariant& returnValue = QVariant()) {    if (context) {        // when a QScriptContext is available throw an actual JS Exception (which can be caught using try/catch on JS side)        context->throwError(message);    } else {        // otherwise just log the error        qCWarning(logger) << "error:" << message;    }    return returnValue;} QObject* createScopedSettings(const QString& scope, QObject* parent, QString& error); class JSAPIExample : public QObject, public QScriptable {    Q_OBJECT    Q_PLUGIN_METADATA(IID "JSAPIExample" FILE "plugin.json")    Q_PROPERTY(QString version MEMBER _version CONSTANT)public:    JSAPIExample() {        setObjectName(JSAPI_EXPORT_NAME);        auto scriptInit = DependencyManager::get<ScriptInitializers>();        if (!scriptInit) {            qCWarning(logger) << "COULD NOT INITIALIZE (ScriptInitializers unavailable)" << qApp << this;            return;        }        qCWarning(logger) << "registering w/ScriptInitializerMixin..." << scriptInit.data();        scriptInit->registerScriptInitializer([this](QScriptEngine* engine) {            auto value = engine->newQObject(this, QScriptEngine::QtOwnership, QScriptEngine::ExcludeDeleteLater);            engine->globalObject().setProperty(objectName(), value);            // qCDebug(logger) << "setGlobalInstance" << objectName() << engine->property("fileName");        });        // qCInfo(logger) << "plugin loaded" << qApp << toString() << QThread::currentThread();    }     // NOTES: everything within the "public slots:" section below will be available from JS via overall plugin QObject    //    also, to demonstrate future-proofing JS API code, QVariant's are used throughout most of these examples --    //    which still makes them very Qt-specific, but avoids depending directly on deprecated QtScript/QScriptValue APIs.    //    (as such this plugin class and its methods remain forward-compatible with other engines like QML's QJSEngine) public slots:    // returns a pretty-printed representation for logging eg: print(JSAPIExample)    inline QString toString() const { return QString("[%1 version=%2]").arg(objectName()).arg(_version); }     /**jsdoc     * Returns current microseconds (usecs) since Epoch. note: 1000usecs == 1ms     * @example <caption>Measure current setTimeout accuracy.</caption>     * var expected = 1000;     * var start = JSAPIExample.now();     * Script.setTimeout(function () {     *     var elapsed = (JSAPIExample.now() - start)/1000;     *     print("expected (ms):", expected, "actual (ms):", elapsed);     * }, expected);     */    QVariant now() const { return usecTimestampNow(); }     /**jsdoc     * Example of returning a JS Object key-value map     * @example <caption>"zip" a list of keys and corresponding values to form key-value map</caption>     * print(JSON.stringify(JSAPIExample.zip(["a","b"], [1,2])); // { "a": 1, "b": 2 }     */    QVariant zip(const QStringList& keys, const QVariantList& values) const {        QVariantMap out;        for (int i = 0; i < keys.size(); i++) {            out[keys[i]] = i < values.size() ? values[i] : QVariant();        }        return out;    }    /**jsdoc     * Example of returning a JS Array result     * @example <caption>emulate Object.values(keyValues)</caption>     * print(JSON.stringify(JSAPIExample.values({ "a": 1, "b": 2 }))); // [1,2]     */    QVariant values(const QVariantMap& keyValues) const { return keyValues.values(); }     /**jsdoc     * Another example of returning JS Array data     * @example <caption>generate an integer sequence (inclusive of [from, to])</caption>     * print(JSON.stringify(JSAPIExample.seq(1,5)));// [1,2,3,4,5]     */    QVariant seq(int from, int to) const {        QVariantList out;        for (int i = from; i <= to; i++) {            out.append(i);        }        return out;    }     /**jsdoc     * Example of returning arbitrary binary data from C++ (resulting in a JS ArrayBuffer)     * see also: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer#Examples     * @example <caption>return compressed/decompressed versions of the input data</caption>     * var data = "testing 1 2 3";     * var z = JSAPIExample.qCompressString(data); // z will be an ArrayBuffer     * var u = JSAPIExample.qUncompressString(z); // u will be a String value     * print(JSON.stringify({ input: data, compressed: z.byteLength, output: u, uncompressed: u.length }));     */    QVariant qCompressString(const QString& data, int compress_level = -1) const {        return qCompress(data.toUtf8(), compress_level);    }    QString qUncompressString(const QByteArray& data) const { return QString::fromUtf8(qUncompress(data)); }     /**      * Example of exposing a custom "managed" C++ QObject to JS      * The lifecycle of the created QObject* instance becomes managed by the invoking QScriptEngine --      * it will be automatically cleaned up once no longer reachable from any JS variables/closures.      * @example <caption>access persistent settings stored in separate .json files</caption>      * var settings = JSAPIExample.getScopedSettings("example");      * print("example settings stored in:", settings.fileName());      * print("(before) example::timestamp", settings.value("timestamp"));      * settings.setValue("timestamp", Date.now());      * print("(after) example::timestamp", settings.value("timestamp"));      * print("all example::* keys", settings.allKeys());      * settings = null; // optional best pratice; allows the object to be reclaimed ASAP by the JS garbage collector      */    QScriptValue getScopedSettings(const QString& scope) {        auto engine = QScriptable::engine();        if (!engine) return QScriptValue::NullValue;        QString error;        auto cppValue = createScopedSettings(scope, engine, error);        if (!cppValue) {          raiseScriptingError(context(), "error creating scoped settings instance: " + error);          return QScriptValue::NullValue;        }        return engine->newQObject(cppValue, QScriptEngine::ScriptOwnership, QScriptEngine::ExcludeDeleteLater);    } private:    const QString _version{ JSAPI_SEMANTIC_VERSION };}; // Example of how to create a QObject class that can have multiple instances created from the JS side// JSSettingsHelper emulates a subset of QSetting APIs://   fileName() -- full path to the scoped settings .json file//   allKeys() -- all previously stored keys available in the scoped settings file//   value(key, defaultValue) -- retrieve a stored value//   setValue(key, newValue) -- set/update a stored valueclass JSSettingsHelper : public QObject {    Q_OBJECT    QString _scope;    QString _fileName;    QSharedPointer<QSettings> _settings; public:    operator bool() const { return (bool)_settings; }    JSSettingsHelper(const QString& scope, QObject* parent = nullptr) :        QObject(parent), _scope(scope), _fileName(getLocalSettingsPath(scope)),        _settings(_fileName.isEmpty() ? nullptr : new QSettings(_fileName, JSON_FORMAT)) {}    ~JSSettingsHelper() { qCDebug(logger) << "~JSSettingsHelper" << _scope << _fileName << this; }public slots:    QString fileName() const { return _settings ? _settings->fileName() : ""; }    QString toString() const { return QString("[JSSettingsHelper scope=%1 valid=%2]").arg(_scope).arg((bool)_settings); }    QVariant value(const QString& key, const QVariant& defaultValue = QVariant()) {        return _settings ? _settings->value(key, defaultValue) : defaultValue;    }    bool setValue(const QString& key, const QVariant& value) {        if (_settings) {            _settings->setValue(key, value);            return true;        }        return false;    }    QStringList allKeys() const { return _settings ? _settings->allKeys() : QStringList{}; } protected:    QString getLocalSettingsPath(const QString& scope) const {        // generate a prefixed filename (relative to the main application's Interface.json file)        const QString fileName = QString("jsapi_%1.json").arg(scope);        return QFileInfo(::settingsFilename()).dir().filePath(fileName);    }}; QObject* createScopedSettings(const QString& scope, QObject* parent, QString& error) {    const QRegExp VALID_SETTINGS_SCOPE{ "[-_A-Za-z0-9]{1,64}" };    if (!VALID_SETTINGS_SCOPE.exactMatch(scope)) {        error = QString("invalid scope (expected alphanumeric <= 64 chars not '%1')").arg(scope);        return nullptr;    }    return new JSSettingsHelper(scope, parent);} }  // namespace REPLACE_ME_WITH_UNIQUE_NAME #include "JSAPIExample.moc"