Issue 6999 - Generate style sheets in background page

lib/contentFiltering.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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/>.
  */
 
 /** @module contentFiltering */
 
 "use strict";
 
 const {RegExpFilter} = require("../adblockpluscore/lib/filterClasses");
-const {ElemHide, createStyleSheet} = require("../adblockpluscore/lib/elemHide");
+const {ElemHide, createStyleSheet,
+       rulesFromStyleSheet} = require("../adblockpluscore/lib/elemHide");
 const {ElemHideEmulation} = require("../adblockpluscore/lib/elemHideEmulation");
 const {filterNotifier} = require("../adblockpluscore/lib/filterNotifier");
 const {Snippets, compileScript} = require("../adblockpluscore/lib/snippets");
 const {checkWhitelisted} = require("./whitelisting");
 const {extractHostFromFrame} = require("./url");
 const {port} = require("./messaging");
 const {HitLogger, logRequest} = require("./hitLogger");
 const info = require("info");
 
 // Chromium's support for tabs.removeCSS is still a work in progress and the
 // API is likely to be different from Firefox's; for now we just don't use it
 // at all, even if it's available.
 // See https://crbug.com/608854
 const styleSheetRemovalSupported = info.platform == "gecko";
 
-const selectorGroupSize = 1024;
-
 let userStyleSheetsSupported = true;
 
 let snippetsLibrarySource = "";
 let executableCode = new Map();
 
 function addStyleSheet(tabId, frameId, styleSheet)
 {
-  let details = {
-    code: styleSheet,
-    frameId,
-    matchAboutBlank: true,
-    runAt: "document_start"
-  };
-
-  if (userStyleSheetsSupported)
-    details.cssOrigin = "user";
-
   try
   {
+    let promise = browser.tabs.insertCSS(tabId, {
+      code: styleSheet,
+      cssOrigin: "user",
+      frameId,
+      matchAboutBlank: true,
+      runAt: "document_start"
+    });
+
     // See error handling notes in the catch block.
-    browser.tabs.insertCSS(tabId, details).catch(() => {});
+    promise.catch(() => {});
   }
   catch (error)
   {
     // If the error is about the "cssOrigin" option, this is an older version
     // of Chromium (65 and below) or Firefox (52 and below) that does not
     // support user style sheets.
-    if (userStyleSheetsSupported && /\bcssOrigin\b/.test(error.message))
-    {
+    if (/\bcssOrigin\b/.test(error.message))
       userStyleSheetsSupported = false;
-
-      return addStyleSheet(tabId, frameId, styleSheet);
-    }
 
     // For other errors, we simply return false to indicate failure.
     //
     // One common error that occurs frequently is when a frame is not found
     // (e.g. "Error: No frame with id 574 in tab 266"), which can happen when
     // the code in the parent document has removed the frame before the
     // background page has had a chance to respond to the content script's
     // "content.applyFilters" message. We simply ignore such errors, because
     // otherwise they show up in the log too often and make debugging
     // difficult.
@@ skipping 14 matching lines @@
     return;
 
   browser.tabs.removeCSS(tabId, {
     code: styleSheet,
     cssOrigin: "user",
     frameId,
     matchAboutBlank: true
   });
 }
 
-function updateFrameStyles(tabId, frameId, selectors, groupName, appendOnly)
-{
-  let styleSheet = "";
-  if (selectors.length > 0)
-    styleSheet = createStyleSheet(selectors);
-
+function updateFrameStyles(tabId, frameId, styleSheet, groupName = "standard",
+                           appendOnly = false)
+{
   let frame = ext.getFrame(tabId, frameId);
   if (!frame)
     return false;
 
   if (!frame.injectedStyleSheets)
     frame.injectedStyleSheets = new Map();
 
   let oldStyleSheet = frame.injectedStyleSheets.get(groupName);
 
   if (appendOnly && oldStyleSheet)
@@ skipping 71 matching lines @@
   {
     // See the comment in the catch block associated with the call to
     // tabs.insertCSS for why we catch any error here and simply
     // return a rejected promise.
     return Promise.reject(error);
   }
 }
 
 port.on("content.applyFilters", (message, sender) =>
 {
-  let selectors = [];
+  let styleSheet = {code: "", selectors: []};
   let emulatedPatterns = [];
   let trace = HitLogger.hasListener(sender.page.id);
+  let inline = !userStyleSheetsSupported;
 
   let {elemhide, snippets} = message.filterTypes ||
                              {elemhide: true, snippets: true};
 
   if (!checkWhitelisted(sender.page, sender.frame, null,
                         RegExpFilter.typeMap.DOCUMENT))
   {
     let docDomain = extractHostFromFrame(sender.frame);
 
     if (snippets)
@@ skipping 13 matching lines @@
           }, filter);
         });
       }
     }
 
     if (elemhide && !checkWhitelisted(sender.page, sender.frame, null,
                                       RegExpFilter.typeMap.ELEMHIDE))
     {
       let specificOnly = checkWhitelisted(sender.page, sender.frame, null,
                                           RegExpFilter.typeMap.GENERICHIDE);
-      selectors = ElemHide.getSelectorsForDomain(docDomain, specificOnly);
+      styleSheet = ElemHide.generateStyleSheetForDomain(docDomain, specificOnly,
+                                                        trace);
 
       for (let filter of ElemHideEmulation.getRulesForDomain(docDomain))
         emulatedPatterns.push({selector: filter.selector, text: filter.text});
     }
   }
 
-  updateFrameStyles(sender.page.id, sender.frame.id, selectors, "standard");
-
-  let response = {trace, emulatedPatterns};
+  if (!inline && !updateFrameStyles(sender.page.id, sender.frame.id,
+                                    styleSheet.code))
+  {
+    inline = true;
+  }
+
+  let response = {trace, inline, emulatedPatterns};
+
+  if (inline)
+    response.rules = [...rulesFromStyleSheet(styleSheet.code)];
+
   if (trace)
-    response.selectors = selectors;
+    response.selectors = styleSheet.selectors;
 
   return response;
 });
 
-port.on("elemhide.injectSelectors", (message, sender) =>
-{
-  updateFrameStyles(sender.page.id, sender.frame.id, message.selectors,
-                    message.groupName, message.appendOnly);
+port.on("content.injectSelectors", (message, sender) =>
+{
+  let styleSheet = createStyleSheet(message.selectors);
+  if (!userStyleSheetsSupported ||
+      !updateFrameStyles(sender.page.id, sender.frame.id, styleSheet,
+                         message.groupName, message.appendOnly))
+  {
+    return [...rulesFromStyleSheet(styleSheet)];
+  }
 });
 
 fetch(browser.extension.getURL("/snippets.js"), {cache: "no-cache"})
 .then(response => response.ok ? response.text() : "")
 .then(text =>
 {
   snippetsLibrarySource = text;
 });