Issue 4948 - add possibility to not send data depending on connection properties

include/AdblockPlus/FilterEngine.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
- * Copyright (C) 2006-2016 Eyeo GmbH
+ * 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_FILTER_ENGINE_H
 #define ADBLOCK_PLUS_FILTER_ENGINE_H
 
 #include <functional>
 #include <map>
 #include <string>
 #include <vector>
 #include <AdblockPlus/JsEngine.h>
 #include <AdblockPlus/JsValue.h>
 #include <AdblockPlus/Notification.h>
 
 namespace AdblockPlus
 {
   class FilterEngine;
+  typedef std::shared_ptr<FilterEngine> FilterEnginePtr;
 
   /**
    * Wrapper for an Adblock Plus filter object.
    * There are no accessors for most
    * [filter properties](https://adblockplus.org/jsdoc/adblockpluscore/Filter.html),
    * use `GetProperty()` to retrieve them by name.
    */
   class Filter : public JsValue,
                  public std::enable_shared_from_this<Filter>
   {
   public:
     /**
      * Filter types, see https://adblockplus.org/en/filters.
      */
     enum Type {TYPE_BLOCKING, TYPE_EXCEPTION,
                TYPE_ELEMHIDE, TYPE_ELEMHIDE_EXCEPTION,
                TYPE_COMMENT, TYPE_INVALID};
 
     /**
      * Retrieves the type of this filter.
      * @return Type of this filter.
      */
-    Type GetType();
+    Type GetType() const;
 
     /**
      * Checks whether this filter has been added to the list of custom filters.
      * @return `true` if this filter has been added.
      */
-    bool IsListed();
+    bool IsListed() const;
 
     /**
      * Adds this filter to the list of custom filters.
      */
     void AddToList();
 
     /**
      * Removes this filter from the list of custom filters.
      */
     void RemoveFromList();
@@ skipping 16 matching lines @@
    * use `GetProperty()` to retrieve them by name.
    */
   class Subscription : public JsValue,
                        public std::enable_shared_from_this<Subscription>
   {
   public:
     /**
      * Checks if this subscription has been added to the list of subscriptions.
      * @return `true` if this subscription has been added.
      */
-    bool IsListed();
+    bool IsListed() const;
 
     /**
      * Adds this subscription to the list of subscriptions.
      */
     void AddToList();
 
     /**
      * Removes this subscription from the list of subscriptions.
      */
     void RemoveFromList();
 
     /**
      * Updates this subscription, i.e.\ retrieves the current filters from the
      * subscription URL.
      */
     void UpdateFilters();
 
     /**
      * Checks if the subscription is currently being updated.
      * @return `true` if the subscription is currently being updated.
      */
-    bool IsUpdating();
+    bool IsUpdating() const;
 
     bool operator==(const Subscription& subscription) const;
 
     /**
      * Creates a wrapper for an existing JavaScript subscription object.
      * Normally you shouldn't call this directly, but use
      * FilterEngine::GetSubscription() instead.
      * @param value JavaScript subscription object.
      */
     Subscription(JsValue&& value);
@@ skipping 76 matching lines @@
      */
     typedef std::map<std::string, AdblockPlus::JsValuePtr> Prefs;
 
     /**
      * Callback type invoked when a new notification should be shown.
      * The parameter is the Notification object to be shown.
      */
     typedef std::function<void(const NotificationPtr&)> ShowNotificationCallback;
 
     /**
-     * Constructor.
+     * Callback function returning false when current connection is not
+     * allowedConnectionType, e.g. because it is a metered connection.
+     */
+    typedef std::function<bool(const std::string* allowedConnectionType)> IsConnectionAllowedCallback;
+
+    /**
+     * FilterEngine creation parameters.
+     */
+    struct CreationParameters
+    {
+      /**
+       * `AdblockPlus::FilterEngine::Prefs` name - value list of preconfigured
+       * prefs.
+       */
+      Prefs preconfiguredPrefs;
+      /**
+       * `AdblockPlus::FilterEngine::IsConnectionAllowedCallback` a callback
+       * checking whether the request from Adblock Plus should be blocked on
+       * the current connection.
+       */
+      IsConnectionAllowedCallback isConnectionAllowedCallback;
+    };
+
+    /**
+    * Callback type invoked when FilterEngine is created.
+    */
+    typedef std::function<void(const FilterEnginePtr&)> OnCreatedCallback;
+
+    /**
+     * Asynchronously constructs FilterEngine.
      * @param jsEngine `JsEngine` instance used to run JavaScript code
      *        internally.
-     * @param preconfiguredPrefs `AdblockPlus::FilterEngine::Prefs`
-     *        name-value list of preconfigured prefs.
+     * @param onCreated A callback which is called when FilterEngine is ready
+     *        for use.
+     * @param parameters optional creation parameters.
      */
-    explicit FilterEngine(JsEnginePtr jsEngine, 
-        const Prefs& preconfiguredPrefs = Prefs()
-      );
+    static void CreateAsync(const JsEnginePtr& jsEngine,
+      const OnCreatedCallback& onCreated,
+      const CreationParameters& parameters = CreationParameters());
+
+    /**
+     * Synchronous interface to construct FilterEngine. For details see
+     * asynchronous version CreateAsync.
+     */
+    static FilterEnginePtr Create(const JsEnginePtr& jsEngine,
+      const CreationParameters& params = CreationParameters());
 
     /**
      * Retrieves the `JsEngine` instance associated with this `FilterEngine`
      * instance.
      */
     JsEnginePtr GetJsEngine() const { return jsEngine; }
 
     /**
      * Checks if this is the first run of the application.
      * @return `true` if the application is running for the first time.
      */
     bool IsFirstRun() const;
 
     /**
      * Retrieves a filter object from its text representation.
      * @param text Text representation of the filter,
      *        see https://adblockplus.org/en/filters.
      * @return New `Filter` instance.
      */
-    FilterPtr GetFilter(const std::string& text);
+    FilterPtr GetFilter(const std::string& text) const;
 
     /**
      * Retrieves a subscription object for the supplied URL.
      * @param url Subscription URL.
      * @return New `Subscription` instance.
      */
-    SubscriptionPtr GetSubscription(const std::string& url);
+    SubscriptionPtr GetSubscription(const std::string& url) const;
 
     /**
      * Retrieves the list of custom filters.
      * @return List of custom filters.
      */
     std::vector<FilterPtr> GetListedFilters() const;
 
     /**
      * Retrieves all subscriptions.
      * @return List of subscriptions.
@@ skipping 104 matching lines @@
      * @param pref Preference name.
      * @param value New value of the preference.
      */
     void SetPref(const std::string& pref, JsValuePtr value);
 
     /**
      * Extracts the host from a URL.
      * @param url URL to extract the host from.
      * @return Extracted host.
      */
-    std::string GetHostFromURL(const std::string& url);
+    std::string GetHostFromURL(const std::string& url) const;
 
     /**
      * Sets the callback invoked when an application update becomes available.
      * @param callback Callback to invoke.
      */
     void SetUpdateAvailableCallback(UpdateAvailableCallback callback);
 
     /**
      * Removes the callback invoked when an application update becomes
      * available.
      */
     void RemoveUpdateAvailableCallback();
 
     /**
      * Forces an immediate update check.
      * `FilterEngine` will automatically check for updates in regular intervals,
      * so applications should only call this when the user triggers an update
      * check manually.
      * @param callback Optional callback to invoke when the update check is
      *        finished. The string parameter will be empty when the update check
      *        succeeded, or contain an error message if it failed.
      *        Note that the callback will be invoked whether updates are
      *        available or not - to react to updates being available, use
      *        `FilterEngine::SetUpdateAvailableCallback()`.
      */
-    void ForceUpdateCheck(UpdateCheckDoneCallback callback);
+    void ForceUpdateCheck(const UpdateCheckDoneCallback& callback = UpdateCheckDoneCallback());
 
     /**
      * Sets the callback invoked when the filters change.
      * @param callback Callback to invoke.
      */
     void SetFilterChangeCallback(FilterChangeCallback callback);
 
     /**
      * Removes the callback invoked when the filters change.
      */
     void RemoveFilterChangeCallback();
 
     /**
+     * Stores the value indicating what connection types are allowed, it is
+     * passed to CreateParameters::isConnectionAllowed callback.
+     * @param value Stored value. nullptr means removing of any previously
+     *        stored value.
+     */
+    void SetAllowedConnectionType(const std::string* value);
+
+    /**
+      * Retrieves previously stored allowed connection type.
+      * @return Preference value, or `nullptr` if it doesn't exist.
+      */
+    std::unique_ptr<std::string> GetAllowedConnectionType() const;
+
+    /**
      * Compares two version strings in
      * [Mozilla toolkit version format](https://developer.mozilla.org/en/docs/Toolkit_version_format).
      * @param v1 First version string.
      * @param v2 Second version string.
      * @return
      *         - `0` if `v1` and `v2` are identical.
      *         - A negative number if `v1` is less than `v2`.
      *         - A positive number if `v1` is greater than `v2`.
      */
-    int CompareVersions(const std::string& v1, const std::string& v2);
+    int CompareVersions(const std::string& v1, const std::string& v2) const;
 
     /**
      * Retrieves the `ContentType` for the supplied string.
      * @param contentType Content type string.
      * @return The `ContentType` for the string.
      * @throw `std::invalid_argument`, if an invalid `contentType` was supplied.
      */
     static ContentType StringToContentType(const std::string& contentType);
 
     /**
      * Retrieves the string representation of the supplied `ContentType`.
      * @param contentType `ContentType` value.
      * @return The string representation of `contentType`.
      * @throw `std::invalid_argument`, if an invalid `contentType` was supplied.
      */
     static std::string ContentTypeToString(ContentType contentType);
 
   private:
     JsEnginePtr jsEngine;
-    bool initialized;
     bool firstRun;
     int updateCheckId;
     static const std::map<ContentType, std::string> contentTypes;
 
-    void InitDone(JsValueList& params);
+    explicit FilterEngine(const JsEnginePtr& jsEngine);
+
     FilterPtr CheckFilterMatch(const std::string& url,
                                ContentTypeMask contentTypeMask,
                                const std::string& documentUrl) const;
     void UpdateAvailable(UpdateAvailableCallback callback, JsValueList& params);
     void UpdateCheckDone(const std::string& eventName,
                          UpdateCheckDoneCallback callback, JsValueList& params);
     void FilterChanged(FilterChangeCallback callback, JsValueList& params);
     void ShowNotification(const ShowNotificationCallback& callback,
       const JsValueList& params);
     FilterPtr GetWhitelistingFilter(const std::string& url,
       ContentTypeMask contentTypeMask, const std::string& documentUrl) const;
     FilterPtr GetWhitelistingFilter(const std::string& url,
       ContentTypeMask contentTypeMask,
       const std::vector<std::string>& documentUrls) const;
   };
 }
 
 #endif