Issue 2401 - Integrate CSS property rule handling in Firefox

lib/child/cssProperties.js

Index: lib/child/cssProperties.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/lib/child/cssProperties.js
@@ -0,0 +1,101 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-2016 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/>.
+ */
+
+"use strict";
+
+(function()
+{
+  let {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
+
+  let {port} = require("messaging");
+  let {getFrames} = require("child/utils");
+
+  let senderWindow = null;
+
+  let scope = {
+    ext: {
+      backgroundPage: {
+        sendMessage: function(data, callback)
+        {
+          data = {payload: data, frames: getFrames(senderWindow)};
+          if (typeof callback == "function")
+            port.emitWithResponse("cssPropertiesRequest", data).then(callback);
+          else
+            port.emit("cssPropertiesRequest", data);
+        }
+      }
+    }
+  };
+
+  function loadScript(script)

[Thomas Greiner, 2016/03/30 18:02:05]

Detail: This function seems redundant since it's only used once and contains
only a single line which is not less descriptive as the function name.

[Wladimir Palant, 2016/03/30 18:42:17]

The idea was originally that this would be a generic content script loading
module but that didn't really work out. Removed.

+  {
+    Services.scriptloader.loadSubScript(script, scope);
+  }
+
+  function addUserCSS(window, cssCode)
+  {
+    let uri = Services.io.newURI("data:text/css," + encodeURIComponent(cssCode),
+        null, null);
+    let utils = window.QueryInterface(Ci.nsIInterfaceRequestor)
+                      .getInterface(Ci.nsIDOMWindowUtils);
+    utils.loadSheet(uri, Ci.nsIDOMWindowUtils.USER_SHEET);
+  }
+
+  function initCSSPropertyFilters()
+  {
+    loadScript("chrome://adblockplus/content/cssProperties.js");
+
+    let onContentWindow = (subject, topic, data) =>
+    {
+      if (!(subject instanceof Ci.nsIDOMWindow))
+        return;
+
+      let onReady = event =>
+      {
+        subject.removeEventListener("DOMContentLoaded", onReady);
+        let handler = new scope.CSSPropertyFilters(subject, selectors =>
+        {
+          if (selectors.length == 0)
+            return;
+
+          addUserCSS(subject, selectors.map(
+            selector => selector + "{display: none !important;}"
+          ).join("\n"));
+        });
+
+        // HACK: The content script just calls ext.backgroundPage.sendMessage
+        // without indicating which window this is about. We'll store the window
+        // here because we know that messaging happens synchronously.

[Wladimir Palant, 2016/03/18 15:25:24]

This is rather ugly. While we made CSSPropertyFilters take window as parameter,
it will still call ext.backgroundPage.sendMessage and expect that the recipient
will automatically know which window this is about. Maybe we should have another
parameter to CSSPropertyFilters constructor called sendMessage? Chrome will
simply pass in ext.backgroundPage.sendMessage there, Firefox will instead pass
some function which is bound to the window in question.

[Thomas Greiner, 2016/03/30 18:02:05]

Can't think of a better alternative than passing a "sendMessage" parameter
either so I'd be fine with that.

[Wladimir Palant, 2016/03/30 18:42:17]

Yes, we'll need to fix this later.

+        senderWindow = subject;
+        handler.load(() => handler.apply());
+        senderWindow = null;
+      };
+
+      subject.addEventListener("DOMContentLoaded", onReady);
+    };
+
+    Services.obs.addObserver(onContentWindow, "content-document-global-created",
+        false);
+    onShutdown.add(() =>
+    {
+      Services.obs.removeObserver(onContentWindow,
+          "content-document-global-created");
+    });
+  }
+
+  initCSSPropertyFilters();
+})();