Issue 4140 - Remove Firefox-specific element hiding functionality

lib/elemHide.js

Index: lib/elemHide.js
===================================================================
--- a/lib/elemHide.js
+++ b/lib/elemHide.js
@@ -14,23 +14,19 @@
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 /**
  * @fileOverview Element hiding implementation.
  */
 
-Cu.import("resource://gre/modules/Services.jsm");
-
-var {Utils} = require("utils");
-var {IO} = require("io");
-var {Prefs} = require("prefs");
-var {ElemHideException} = require("filterClasses");
-var {FilterNotifier} = require("filterNotifier");
+let {Utils} = require("utils");
+let {ElemHideException} = require("filterClasses");
+let {FilterNotifier} = require("filterNotifier");
 
 /**
  * Lookup table, filters by their associated key
  * @type Object
  */
 var filterByKey = [];
 
 /**
@@ -81,70 +77,34 @@ var knownExceptions = Object.create(null
 
 /**
  * Lookup table, lists of element hiding exceptions by selector
  * @type Object
  */
 var exceptions = Object.create(null);
 
 /**
- * Currently applied stylesheet URL
- * @type nsIURI
- */
-var styleURL = null;
-
-/**
- * Element hiding component
+ * Container for element hiding filters
  * @class
  */
 var ElemHide = exports.ElemHide =
 {
   /**
-   * Indicates whether filters have been added or removed since the last apply() call.
-   * @type Boolean
-   */
-  isDirty: false,
-
-  /**
-   * Indicates whether the element hiding stylesheet is currently applied.
-   * @type Boolean
-   */
-  applied: false,
-
-  /**
-   * Called on module startup.
-   */
-  init: function()
-  {
-    Prefs.addListener(function(name)
-    {
-      if (name == "enabled")
-        ElemHide.apply();
-    });
-    onShutdown.add(() => ElemHide.unapply());
-
-    let styleFile = IO.resolveFilePath(Prefs.data_directory);
-    styleFile.append("elemhide.css");
-    styleURL = Services.io.newFileURI(styleFile).QueryInterface(Ci.nsIFileURL);
-  },
-
-  /**
    * Removes all known filters
    */
   clear: function()
   {
     filterByKey = [];
     keyByFilter = Object.create(null);
     filtersByDomain = Object.create(null);
     filtersBySelector = Object.create(null);
     unconditionalSelectors = null;
     knownExceptions = Object.create(null);
     exceptions = Object.create(null);
-    ElemHide.isDirty = false;
-    ElemHide.unapply();
+    FilterNotifier.emit("elemhideupdate");
   },
 
   _addToFiltersByDomain: function(filter)
   {
     let key = keyByFilter[filter.text];
     let domains = filter.domains || defaultDomains;
     for (let domain in domains)
     {
@@ -217,19 +177,19 @@ var ElemHide = exports.ElemHide =
           }
         }
         else
         {
           // The new filter's selector only applies to some domains
           this._addToFiltersByDomain(filter);
         }
       }
+    }
 
-      ElemHide.isDirty = true;
-    }
+    FilterNotifier.emit("elemhideupdate");
   },
 
   /**
    * Removes an element hiding filter
    * @param {ElemHideFilter} filter
    */
   remove: function(filter)
   {
@@ -247,17 +207,16 @@ var ElemHide = exports.ElemHide =
     else
     {
       if (!(filter.text in keyByFilter))
         return;
 
       let key = keyByFilter[filter.text];
       delete filterByKey[key];
       delete keyByFilter[filter.text];
-      ElemHide.isDirty = true;
 
       if (usingGetSelectorsForDomain)
       {
         let filters = filtersBySelector[filter.selector];
         if (filters)
         {
           if (filters.length > 1)
           {
@@ -277,16 +236,18 @@ var ElemHide = exports.ElemHide =
           {
             let filters = filtersByDomain[domain];
             if (filters)
               delete filters[key];
           }
         }
       }
     }
+
+    FilterNotifier.emit("elemhideupdate");
   },
 
   /**
    * Checks whether an exception rule is registered for a filter on a particular
    * domain.
    */
   getException: function(/**Filter*/ filter, /**String*/ docDomain) /**ElemHideException*/
   {
@@ -297,200 +258,48 @@ var ElemHide = exports.ElemHide =
     for (let i = list.length - 1; i >= 0; i--)
       if (list[i].isActiveOnDomain(docDomain))
         return list[i];
 
     return null;
   },
 
   /**
-   * Will be set to true if apply() is running (reentrance protection).
-   * @type Boolean
+   * Retrieves an element hiding filter by the corresponding protocol key
    */
-  _applying: false,
+  getFilterByKey: function(/**String*/ key) /**Filter*/
+  {
+    return (key in filterByKey ? filterByKey[key] : null);
+  },
 
   /**
-   * Will be set to true if an apply() call arrives while apply() is already
-   * running (delayed execution).
-   * @type Boolean
+   * Returns a list of all selectors as a nested map. On first level, the keys
+   * are all values of `ElemHideBase.selectorDomain` (domains on which these
+   * selectors should apply, ignoring exceptions). The values are maps again,
+   * with the keys being selectors and values the corresponding filter keys.
+   * @returns {Map.<String,Map<String,String>>}
    */
-  _needsApply: false,
-
-  /**
-   * Generates stylesheet URL and applies it globally
-   */
-  apply: function()
+  getSelectors: function()
   {
-    if (this._applying)
-    {
-      this._needsApply = true;
-      return;
-    }
-
-    if (!ElemHide.isDirty || !Prefs.enabled)
-    {
-      // Nothing changed, looks like we merely got enabled/disabled
-      if (Prefs.enabled && !ElemHide.applied)
-      {
-        try
-        {
-          Utils.styleService.loadAndRegisterSheet(styleURL, Ci.nsIStyleSheetService.USER_SHEET);
-          ElemHide.applied = true;
-        }
-        catch (e)
-        {
-          Cu.reportError(e);
-        }
-      }
-      else if (!Prefs.enabled && ElemHide.applied)
-      {
-        ElemHide.unapply();
-      }
-
-      return;
-    }
-
-    IO.writeToFile(styleURL.file, this._generateCSSContent(), function(e)
-    {
-      this._applying = false;
-
-      // _generateCSSContent is throwing NS_ERROR_NOT_AVAILABLE to indicate that
-      // there are no filters. If that exception is passed through XPCOM we will
-      // see a proper exception here, otherwise a number.
-      let noFilters = (e == Cr.NS_ERROR_NOT_AVAILABLE || (e && e.result == Cr.NS_ERROR_NOT_AVAILABLE));
-      if (noFilters)
-      {
-        e = null;
-        IO.removeFile(styleURL.file, function(e) {});
-      }
-      else if (e)
-        Cu.reportError(e);
-
-      if (this._needsApply)
-      {
-        this._needsApply = false;
-        this.apply();
-      }
-      else if (!e)
-      {
-        ElemHide.isDirty = false;
-
-        ElemHide.unapply();
-
-        if (!noFilters)
-        {
-          try
-          {
-            Utils.styleService.loadAndRegisterSheet(styleURL, Ci.nsIStyleSheetService.USER_SHEET);
-            ElemHide.applied = true;
-          }
-          catch (e)
-          {
-            Cu.reportError(e);
-          }
-        }
-
-        FilterNotifier.triggerListeners("elemhideupdate");
-      }
-    }.bind(this));
-
-    this._applying = true;
-  },
-
-  _generateCSSContent: function*()
-  {
-    // Grouping selectors by domains
-    let domains = Object.create(null);
-    let hasFilters = false;
+    let domains = new Map();
     for (let key in filterByKey)
     {
       let filter = filterByKey[key];
       let selector = filter.selector;
       if (!selector)
         continue;
 
       let domain = filter.selectorDomain || "";
 
-      let list;
-      if (domain in domains)
-        list = domains[domain];
-      else
-      {
-        list = Object.create(null);
-        domains[domain] = list;
-      }
-      list[selector] = key;
-      hasFilters = true;
+      if (!domains.has(domain))
+        domains.set(domain, new Map());
+      domains.get(domain).set(selector, key);
     }
 
-    if (!hasFilters)
-      throw Cr.NS_ERROR_NOT_AVAILABLE;
-
-    function escapeChar(match)
-    {
-      return "\\" + match.charCodeAt(0).toString(16) + " ";
-    }
-
-    // Return CSS data
-    let cssTemplate = "-moz-binding: url(about:abp-elemhidehit?%ID%#dummy) !important;";
-    for (let domain in domains)
-    {
-      let rules = [];
-      let list = domains[domain];
-
-      if (domain)
-        yield ('@-moz-document domain("' + domain.split(",").join('"),domain("') + '"){').replace(/[^\x01-\x7F]/g, escapeChar);
-      else
-      {
-        // Only allow unqualified rules on a few protocols to prevent them from blocking chrome
-        yield '@-moz-document url-prefix("http://"),url-prefix("https://"),'
-                  + 'url-prefix("mailbox://"),url-prefix("imap://"),'
-                  + 'url-prefix("news://"),url-prefix("snews://"){';
-      }
-
-      for (let selector in list)
-        yield selector.replace(/[^\x01-\x7F]/g, escapeChar) + "{" + cssTemplate.replace("%ID%", list[selector]) + "}";
-      yield '}';
-    }
-  },
-
-  /**
-   * Unapplies current stylesheet URL
-   */
-  unapply: function()
-  {
-    if (ElemHide.applied)
-    {
-      try
-      {
-        Utils.styleService.unregisterSheet(styleURL, Ci.nsIStyleSheetService.USER_SHEET);
-      }
-      catch (e)
-      {
-        Cu.reportError(e);
-      }
-      ElemHide.applied = false;
-    }
-  },
-
-  /**
-   * Retrieves the currently applied stylesheet URL
-   * @type String
-   */
-  get styleURL()
-  {
-    return ElemHide.applied ? styleURL.spec : null;
-  },
-
-  /**
-   * Retrieves an element hiding filter by the corresponding protocol key
-   */
-  getFilterByKey: function(/**String*/ key) /**Filter*/
-  {
-    return (key in filterByKey ? filterByKey[key] : null);
+    return domains;
   },
 
   /**
    * Returns a list of all selectors active on a particular domain, must not be
    * used in Firefox (when usingGetSelectorsForDomain is false).
    */
   getSelectorsForDomain: function(/**String*/ domain, /**Boolean*/ specificOnly)
   {