Issue 5450 - introduce the Platform class

include/AdblockPlus/Platform.h

+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-2017 eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef ADBLOCK_PLUS_PLATFORM_H
+#define ADBLOCK_PLUS_PLATFORM_H
+
+#include "LogSystem.h"
+#include "ITimer.h"
+#include "IFileSystem.h"
+#include "IWebRequest.h"
+#include "AppInfo.h"
+#include "Scheduler.h"
+#include <mutex>
+
+namespace AdblockPlus
+{
+  /**
+   * A factory to construct DefaultTimer.
+   */
+  TimerPtr CreateDefaultTimer();
+
+  /**
+   * A factory to construct DefaultFileSystem.
+   */
+  FileSystemPtr CreateDefaultFileSystem(const Scheduler& scheduler);
+
+  /**
+   * A factory to construct DefaultWebRequest.
+   */
+  WebRequestPtr CreateDefaultWebRequest(const Scheduler& scheduler);
+
+  /**
+   * A factory to construct LogSystem.
+   */
+  LogSystemPtr CreateDefaultLogSystem();
+
+  class JsEngine;
+
+  /**
+   * AdblockPlus platform is the main component providing access to other
+   * modules.
+   *
+   * It manages the functionality modules, e.g. JsEngine and FilterEngine as
+   * well as allows to correctly work with asynchronous functionality.
+   */
+  class Platform
+  {
+  public:
+    /**
+     * Platform creation parameters.
+     *
+     * @param logSystem Implementation of log system.
+     * @param timer Implementation of timer.
+     * @param webRequest Implementation of web request.
+     * @param fileSystem Implementation of filesystem.
+     */
+    struct CreationParameters
+    {
+      LogSystemPtr logSystem;
+      TimerPtr timer;
+      WebRequestPtr webRequest;
+      FileSystemPtr fileSystem;
+    };
+
+    /**
+     * Platform constructor.
+     *
+     * When a parameter value is nullptr the corresponding default
+     * implementation is chosen.
+     */
+    explicit Platform(CreationParameters&& creationParameters = CreationParameters());
+    ~Platform();
+
+    /**
+     * Ensures that JsEngine is constructed.
+     *
+     * @param appInfo Information about the app, if jsEngine is already present
+     *        then the value is ignored.
+     */
+    void SetUpJsEngine(const AppInfo& appInfo = AppInfo());
+
+    /**
+     * Retrieves the `JsEngine` instance. It calls SetUpJsEngine if JsEngine is
+     * not initialized yet.
+     */
+    std::shared_ptr<JsEngine> GetJsEngine();
+
+    /**
+    * @return The asynchronous ITimer implementation.
+     */
+    ITimer& GetTimer();
+
+    /**
+     * @return The asynchronous IFileSystem implementation.
+     */
+    IFileSystem& GetFileSystem();
+
+    /**
+    * @return The asynchronous IWebRequest implementation.
+    */
+    IWebRequest& GetWebRequest();
+
+    /**
+     * @see `SetLogSystem()`.
+     */
+    LogSystem& GetLogSystem();
+
+  private:
+    LogSystemPtr logSystem;
+    TimerPtr timer;
+    FileSystemPtr fileSystem;
+    WebRequestPtr webRequest;
+    // used for creation and deletion of modules.
+    std::mutex modulesMutex;
+    std::shared_ptr<JsEngine> jsEngine;
+  };
+}
+
+#endif // ADBLOCK_PLUS_PLATFORM_H