Issue 5183 - Provide async interface for FileSystem

include/AdblockPlus/JsEngine.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
@@ skipping 38 matching lines @@
    * Shared smart pointer to a `JsEngine` instance.
    */
   typedef std::shared_ptr<JsEngine> JsEnginePtr;
 
   /**
    * A factory to construct DefaultTimer.
    */
   TimerPtr CreateDefaultTimer();
 
   /**
+   * A factory to construct DefaultFileSystem.
+   */
+  FileSystemPtr CreateDefaultFileSystem();
+
+  /**
    * A factory to construct DefaultWebRequest.
    */
   WebRequestPtr CreateDefaultWebRequest();
 
   /**
    * Scope based isolate manager. Creates a new isolate instance on
    * constructing and disposes it on destructing.
    */
   class ScopedV8Isolate
   {
@@ skipping 15 matching lines @@
    * JavaScript engine used by `FilterEngine`, wraps v8.
    */
   class JsEngine : public std::enable_shared_from_this<JsEngine>
   {
     friend class JsValue;
     friend class JsContext;
 
     struct JsWeakValuesList
     {
       ~JsWeakValuesList();
       std::vector<v8::Global<v8::Value>> values;

[sergei, 2017/07/03 09:25:54]

Wow, it seems to be rebased on new v8. That's very cool, I would only like to
ask to submit a new patch set after landing of
https://codereview.adblockplus.org/29451722/.

[hub, 2017/07/04 19:58:27]

Yes I did rebase on top of your patch. I was expecting it to land already. I
will definitely wait for it and rebase on master at that point.

     };
     typedef std::list<JsWeakValuesList> JsWeakValuesLists;
   public:
     /**
      * Event callback function.
      */
     typedef std::function<void(JsValueList&& params)> EventCallback;
 
     /**
      * Maps events to callback functions.
      */
     typedef std::map<std::string, EventCallback> EventMap;
 
     /**
      * An opaque structure representing ID of stored JsValueList.
      * 
      */
     class JsWeakValuesID
     {
       friend class JsEngine;
       JsWeakValuesLists::const_iterator iterator;
     };
 
     /**
      * Creates a new JavaScript engine instance.
      * @param appInfo Information about the app.
      * @param timer Implementation of timer.
+     * @param fileSystem Implementation of filesystem.
      * @param webRequest Implementation of web request.
      * @param isolate v8::Isolate wrapper. This parameter should be considered
      *        as a temporary hack for tests, it will go away. Issue #3593.
      * @return New `JsEngine` instance.
      */
     static JsEnginePtr New(const AppInfo& appInfo = AppInfo(),
       TimerPtr timer = CreateDefaultTimer(),
+      FileSystemPtr fileSystem = CreateDefaultFileSystem(),
       WebRequestPtr webRequest = CreateDefaultWebRequest());
 
     /**
      * Registers the callback function for an event.
      * @param eventName Event name. Note that this can be any string - it's a
      *        general purpose event handling mechanism.
      * @param callback Event callback function.
      */
     void SetEventCallback(const std::string& eventName, const EventCallback& callback);
 
@@ skipping 111 matching lines @@
 
     /**
      * Converts v8 arguments to `JsValue` objects.
      * @param arguments `v8::FunctionCallbackInfo` object containing the arguments to
      *        convert.
      * @return List of arguments converted to `const JsValue` objects.
      */
     JsValueList ConvertArguments(const v8::FunctionCallbackInfo<v8::Value>& arguments);
 
     /**
-     * @see `SetFileSystem()`.
+     * @return The asynchronous IFileSystem implementation.
      */
-    FileSystemPtr GetFileSystem() const;
+    FileSystemPtr GetAsyncFileSystem() const;

[sergei, 2017/07/03 09:25:54]

From
https://codereview.adblockplus.org/29449592/diff/29454687/include/AdblockPlus...
On 2017/06/16 21:52:54, hub wrote:
Could you please say in the comment to the getter that it's a private
functionality?

[hub, 2017/07/04 19:58:26]

Acknowledged.

 
     /**
-     * Sets the `FileSystem` implementation used for all file I/O.
-     * Setting this is optional, the engine will use a `DefaultFileSystem`
-     * instance by default, which might be sufficient.
+     * Sets the synchronous `FileSystem` implementation used for all
+     * file I/O. Setting this is optional, the engine will use a
+     * `DefaultFileSystemSync` instance by default, which might be

[sergei, 2017/07/03 09:25:54]

I think the comment should be a bit adjusted. By default the engine will use the
implementation created by `CreateDefaultFileSystem()`. The latter internally is
indeed currently based on `DefaultFileSystemSync` but I think it's a detail of
internal implementation.

[hub, 2017/07/04 19:58:26]

Acknowledged.

+     * sufficient.
      * @param The `FileSystem` instance to use.
      */
-    void SetFileSystem(const FileSystemPtr& val);
+    void SetFileSystem(const FileSystemSyncPtr& val);
 
     /**
      * Sets the `WebRequest` implementation used for XMLHttpRequests.
      * Setting this is optional, the engine will use a `DefaultWebRequest`
      * instance by default, which might be sufficient.
      * @param The `WebRequest` instance to use.
      */
     void SetWebRequest(const WebRequestSharedPtr& val);
 
     /**
@@ skipping 26 matching lines @@
     }
 
     /**
      * Notifies JS engine about critically low memory what should cause a
      * garbage collection.
      */
     void NotifyLowMemory();
   private:
     void CallTimerTask(const JsWeakValuesID& timerParamsID);
 
-    explicit JsEngine(TimerPtr timer, WebRequestPtr webRequest);
+    explicit JsEngine(TimerPtr timer, FileSystemPtr fileSystem, WebRequestPtr webRequest);
 
     JsValue GetGlobalObject();
 
     /// Isolate must be disposed only after disposing of all objects which are
     /// using it.
     ScopedV8Isolate isolate;
 
     FileSystemPtr fileSystem;
+    FileSystemSyncPtr fileSystemLegacy;
     LogSystemPtr logSystem;
     std::unique_ptr<v8::Global<v8::Context>> context;
     EventMap eventCallbacks;
     std::mutex eventCallbacksMutex;
     JsWeakValuesLists jsWeakValuesLists;
     std::mutex jsWeakValuesListsMutex;
     TimerPtr timer;
     WebRequestPtr webRequest;
     WebRequestSharedPtr webRequestLegacy;
   };
 }
 
 #endif