WIP: Have one global element hide stylesheet and inject the other ones per site

lib/elemHide.js

Index: lib/elemHide.js
===================================================================
--- a/lib/elemHide.js
+++ b/lib/elemHide.js
@@ -136,16 +136,48 @@ let ElemHide = exports.ElemHide =
       return;
 
     if (!Prefs.enabled)
       return;
 
     if (Policy.shouldNeverBlockWindow(subject))
       return;
 
+    let domain = null;
+    let filters = null;
+     try
+     {
+      domain = subject.document.documentURIObject.host;
+      if (domain)
+        filters = ElemHide.getFiltersWithKeyForDomain(domain, true);
+    } catch (e) {}
+
+    if (filters)
+    {
+      let list = Object.create(null);
+      for (let {key, filter} of filters)
+        list[key] = filter;
+
+      let css = "";
+      for (let line in this._generateCSSContent(list, false))
+        css += line + "\n";
+
+      let uri = Services.io.newURI("data:text/css;base64," + btoa(css), null, null);
+      try
+      {
+        let utils = subject.QueryInterface(Ci.nsIInterfaceRequestor)
+                           .getInterface(Ci.nsIDOMWindowUtils);
+        utils.loadSheet(uri, Ci.nsIStyleSheetService.USER_SHEET);
+      }
+      catch (e)
+      {
+        Cu.reportError(e);
+      }
+    }
+
     if (styleSheet)
     {
       try
       {
         let utils = subject.QueryInterface(Ci.nsIInterfaceRequestor)
                            .getInterface(Ci.nsIDOMWindowUtils);
         utils.addSheet(styleSheet, Ci.nsIStyleSheetService.USER_SHEET);
       }
@@ -296,17 +328,17 @@ let ElemHide = exports.ElemHide =
         ElemHide.unapply();
         TimeLine.log("ElemHide.unapply() finished");
       }
 
       TimeLine.leave("ElemHide.apply() done (no file changes)");
       return;
     }
 
-    IO.writeToFile(styleURL.file, this._generateCSSContent(), function(e)
+    IO.writeToFile(styleURL.file, this._generateCSSContent(filterByKey, useNew), function(e)
     {
       TimeLine.enter("ElemHide.apply() write callback");
       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));
@@ -340,39 +372,43 @@ let ElemHide = exports.ElemHide =
               styleSheet = Utils.styleService.preloadSheet(styleURL, Ci.nsIStyleSheetService.USER_SHEET);
             ElemHide.applied = true;
           }
           catch (e)
           {
             Cu.reportError(e);
           }
           TimeLine.log("Applying stylesheet finished");
+          Cu.reportError("applying finished");
         }
 
         FilterNotifier.triggerListeners("elemhideupdate");
       }
       TimeLine.leave("ElemHide.apply() write callback done");
     }.bind(this), "ElemHideWrite");
 
     this._applying = true;
 
     TimeLine.leave("ElemHide.apply() done", "ElemHideWrite");
   },
 
-  _generateCSSContent: function()
+  _generateCSSContent: function(filters, onlyGlobal)
   {
     // Grouping selectors by domains
     TimeLine.log("start grouping selectors");
     let domains = Object.create(null);
     let hasFilters = false;
-    for (let key in filterByKey)
+    for (let key in filters)
     {
-      let filter = filterByKey[key];
+      let filter = filters[key];
       let domain = filter.selectorDomain || "";
 
+      if (onlyGlobal && domain)
+        continue;
+
       let list;
       if (domain in domains)
         list = domains[domain];
       else
       {
         list = Object.create(null);
         domains[domain] = list;
       }
@@ -458,10 +494,27 @@ let ElemHide = exports.ElemHide =
 
       if (specificOnly && (!domains || domains[""]))
         continue;
 
       if (filter.isActiveOnDomain(domain) && !this.getException(filter, domain))
         result.push(filter.selector);
     }
     return result;
+  },
+
+  getFiltersWithKeyForDomain: function(/**String*/ domain)
+  {
+    let result = [];
+    for (let key in filterByKey)
+    {
+      let filter = filterByKey[key];
+
+      if (!filter.domains)
+        continue
+
+      if (filter.isActiveOnDomain(domain) && !this.getException(filter, domain))
+        result.push({key, filter});
+    }
+    return result;
   }
+
 };