Issue 524 - Stop using @-moz-document

lib/child/elemHide.js

Index: lib/child/elemHide.js
===================================================================
--- a/lib/child/elemHide.js
+++ b/lib/child/elemHide.js
@@ -11,17 +11,17 @@
  * 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/>.
  */
 
 /**
- * @fileOverview Hit counts for element hiding.
+ * @fileOverview Serves CSS for element hiding and processes hits.
  */
 
 try
 {
   // Hack: SDK loader masks our Components object with a getter.
   let proto = Object.getPrototypeOf(this);
   let property = Object.getOwnPropertyDescriptor(proto, "Components");
   if (property && property.get)
@@ -36,22 +36,16 @@ let {XPCOMUtils} = Cu.import("resource:/
 let {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
 
 let {shouldAllowAsync} = require("child/contentPolicy");
 let {getFrames, isPrivate} = require("child/utils");
 let {RequestNotifier} = require("child/requestNotifier");
 let {port} = require("messaging");
 let {Utils} = require("utils");
 
-// The allowXBL binding below won't have any effect on the element. For elements
-// that should be hidden however we don't return any binding at all, this makes
-// Gecko stop constructing the node - it cannot be shown.
-const allowXBL = "<bindings xmlns='http://www.mozilla.org/xbl'><binding id='dummy' bindToUntrustedContent='true'/></bindings>";
-const hideXBL = "<bindings xmlns='http://www.mozilla.org/xbl'/>";
-
 const notImplemented = () => Cr.NS_ERROR_NOT_IMPLEMENTED;
 
 /**
  * about: URL module used to count hits.
  * @class
  */
 let AboutHandler =
 {
@@ -91,24 +85,28 @@ let AboutHandler =
 
   getURIFlags: function(uri)
   {
     return Ci.nsIAboutModule.HIDE_FROM_ABOUTABOUT;
   },
 
   newChannel: function(uri, loadInfo)
   {
-    let match = /\?(?:hit(\d+)|css)$/.exec(uri.path);
-    if (!match)
-      throw Cr.NS_ERROR_FAILURE;
+    let match = /\?hit(\d+)$/.exec(uri.path);
+    if (match)
+      return new HitRegistrationChannel(uri, loadInfo, match[1]);
 
-    if (match[1])
-      return new HitRegistrationChannel(uri, loadInfo, match[1]);
-    else
-      return new StyleDataChannel(uri, loadInfo);
+    match = /\?css(?:=(.*?))?$/.exec(uri.path);
+    if (match)
+    {
+      return new StyleDataChannel(uri, loadInfo,
+            match[1] ? decodeURIComponent(match[1]) : null);
+    }
+
+    throw Cr.NS_ERROR_FAILURE;
   },
 
   QueryInterface: XPCOMUtils.generateQI([Ci.nsIFactory, Ci.nsIAboutModule])
 };
 AboutHandler.init();
 
 /**
  * Base class for channel implementations, subclasses usually only need to
@@ -207,68 +205,52 @@ BaseChannel.prototype = {
   cancel: notImplemented,
   suspend: notImplemented,
   resume: notImplemented,
 
   QueryInterface: XPCOMUtils.generateQI([Ci.nsIChannel, Ci.nsIRequest])
 };
 
 /**
- * Channel returning CSS data for the global stylesheet.
+ * Channel returning CSS data for the global as well as site-specific stylesheet.
  * @constructor
  */
-function StyleDataChannel(uri, loadInfo)
+function StyleDataChannel(uri, loadInfo, domain)
 {
   BaseChannel.call(this, uri, loadInfo);
+  this._domain = domain;
 }
 StyleDataChannel.prototype = {
   __proto__: BaseChannel.prototype,
   contentType: "text/css",
+  _domain: null,
 
   _getResponse: function()
   {
     function escapeChar(match)
     {
       return "\\" + match.charCodeAt(0).toString(16) + " ";
     }
 
     // Would be great to avoid sync messaging here but nsIStyleSheetService
     // insists on opening channels synchronously.
-    let domains = port.emitSync("getSelectors");
+    let [selectors, keys] = (this._domain ?
+        port.emitSync("getSelectorsForDomain", this._domain) :
+        port.emitSync("getUnconditionalSelectors"));
 
     let cssPrefix = "{-moz-binding: url(about:abp-elemhide?hit";
     let cssSuffix = "#dummy) !important;}\n";
     let result = [];
 
-    for (let [domain, selectors] of domains)
+    for (let i = 0; i < selectors.length; i++)
     {
-      if (domain)
-      {
-        result.push('@-moz-document domain("',
-            domain.replace(/[^\x01-\x7F]/g, escapeChar)
-                  .split(",").join('"),domain("'),
-            '"){\n');
-      }
-      else
-      {
-        // Only allow unqualified rules on a few protocols to prevent them
-        // from blocking chrome content
-        result.push('@-moz-document url-prefix("http://"),',
-            'url-prefix("https://"),url-prefix("mailbox://"),',
-            'url-prefix("imap://"),url-prefix("news://"),',
-            'url-prefix("snews://"){\n');
-      }
-
-      for (let [selector, key] of selectors)
-      {
-        result.push(selector.replace(/[^\x01-\x7F]/g, escapeChar),
-            cssPrefix, key, cssSuffix);
-      }
-
-      result.push("}\n");
+      let selector = selectors[i];
+      let key = keys[i];
+      result.push(selector.replace(/[^\x01-\x7F]/g, escapeChar),
+          cssPrefix, key, cssSuffix);
     }
 
     return result.join("");
   }
 };
 
 /**
  * Channel returning data for element hiding hits.
@@ -281,24 +263,27 @@ function HitRegistrationChannel(uri, loa
 }
 HitRegistrationChannel.prototype = {
   __proto__: BaseChannel.prototype,
   key: null,
   contentType: "text/xml",
 
   _getResponse: function()
   {
-    return new Promise((resolve, reject) =>
+    let window = Utils.getRequestWindow(this);
+    port.emitWithResponse("registerElemHideHit", {
+      key: this.key,
+      frames: getFrames(window),
+      isPrivate: isPrivate(window)
+    }).then(hit =>
     {
-      let window = Utils.getRequestWindow(this);
-      shouldAllowAsync(window, window.document, "ELEMHIDE", this.key, allow =>
-      {
-        resolve(allow ? allowXBL : hideXBL);
-      });
+      if (hit)
+        RequestNotifier.addNodeData(window.document, window.top, hit);

[kzar, 2016/10/06 13:02:32]

(Doesn't storing all the details returned by registerElemHideHit for each hidden
element add quite a bit of overhead? On the other hand I guess it's kind of
useful to know when element hiding filters have matched.)

[Wladimir Palant, 2016/10/06 13:08:48]

That's how the list of blockable items works - it needs to show everything that
affected the display of the current page. Not having element hiding in there
would leave out an important piece of the data.

The other feature using this data is the issue reporter - it also needs to know
which filters matched on the current page.

     });
+    return "<bindings xmlns='http://www.mozilla.org/xbl'/>";
   }
 };
 
 let observer = {
   QueryInterface: XPCOMUtils.generateQI([
     Ci.nsIObserver, Ci.nsISupportsWeakReference
   ]),
 
@@ -370,16 +355,34 @@ let observer = {
         catch (e)
         {
           // Ignore NS_ERROR_ILLEGAL_VALUE - it will be thrown if we try to add
           // the stylesheet multiple times to the same document (the observer
           // will be notified twice for some documents).
           if (e.result != Cr.NS_ERROR_ILLEGAL_VALUE)
             throw e;
         }
+
+        let host = subject.location.hostname;
+        if (host)
+        {
+          try
+          {
+            utils.loadSheetUsingURIString(this.styleURL.spec + "=" +
+                encodeURIComponent(host), Ci.nsIStyleSheetService.USER_SHEET);
+          }
+          catch (e)
+          {
+            // Ignore NS_ERROR_ILLEGAL_VALUE - it will be thrown if we try to add
+            // the stylesheet multiple times to the same document (the observer
+            // will be notified twice for some documents).
+            if (e.result != Cr.NS_ERROR_ILLEGAL_VALUE)
+              throw e;
+          }
+        }
       }
       else if (filter)
       {
         RequestNotifier.addNodeData(window.document, window.top, {
           contentType, docDomain, thirdParty, location, filter, filterType
         });
       }
     });