Issue 5899 - Use CSS attribute selectors for collapsing media elements

lib/cssInjection.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 cssInjection */
 
 "use strict";
 
-const {RegExpFilter} = require("filterClasses");
-const {ElemHide} = require("elemHide");
-const {ElemHideEmulation} = require("elemHideEmulation");
-const {checkWhitelisted} = require("whitelisting");
-const {extractHostFromFrame} = require("url");
-const {port} = require("messaging");
-const devtools = require("devtools");
-const info = require("info");
+const {RegExpFilter} = require("../adblockpluscore/lib/filterClasses");
+const {ElemHide} = require("../adblockpluscore/lib/elemHide");
+const {ElemHideEmulation} = require("../adblockpluscore/lib/elemHideEmulation");
+const {checkWhitelisted} = require("./whitelisting");
+const {extractHostFromFrame} = require("./url");
+const {port} = require("./messaging");
+const devtools = require("./devtools");
+const info = require("../buildtools/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;
@@ skipping 23 matching lines @@
 
 function createStyleSheet(selectors)
 {
   return Array.from(createRules(selectors)).join("\n");
 }
 
 function addStyleSheet(tabId, frameId, styleSheet)
 {
   try
   {
-    browser.tabs.insertCSS(tabId, {
+    let promise = browser.tabs.insertCSS(tabId, {
       code: styleSheet,
       cssOrigin: "user",
       frameId,
       matchAboutBlank: true,
       runAt: "document_start"
     });
+
+    // See error handling notes in the catch block.
+    promise.catch(() => {});
   }
   catch (error)
   {
-    userStyleSheetsSupported = false;
-  }
-
-  return userStyleSheetsSupported;
+    // 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 (/\bcssOrigin\b/.test(error.message))
+      userStyleSheetsSupported = false;
+
+    // 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
+    // "elemhide.getSelectors" message. We simply ignore such errors, because
+    // otherwise they show up in the log too often and make debugging
+    // difficult.
+    //
+    // Also note that the missing frame error is thrown synchronously on
+    // Firefox, while on Chromium it is an asychronous promise rejection. In
+    // the latter case, we cannot indicate failure to the caller, but we still
+    // explicitly ignore the error.
+    return false;
+  }
+
+  return true;
 }
 
 function removeStyleSheet(tabId, frameId, styleSheet)
 {
   if (!styleSheetRemovalSupported)
     return;
 
   browser.tabs.removeCSS(tabId, {
     code: styleSheet,
     cssOrigin: "user",
     frameId,
     matchAboutBlank: true
   });
 }
 
 function updateFrameStyles(tabId, frameId, selectors, groupName, appendOnly)
 {
   let styleSheet = "";

[Manish Jethani, 2018/02/27 16:00:22]

I changed this to an empty string because it doesn't make a difference to the
rest of the code but string concatenation works as expected.

[kzar, 2018/02/27 17:25:22]

Acknowledged.

   if (selectors.length > 0)
     styleSheet = createStyleSheet(selectors);
 
   let frame = ext.getFrame(tabId, frameId);
   if (!frame)
     return false;
 
   if (!frame.injectedStyleSheets)
     frame.injectedStyleSheets = new Map();
 
@@ skipping 19 matching lines @@
     removeStyleSheet(tabId, frameId, oldStyleSheet);
 
   frame.injectedStyleSheets.set(groupName, styleSheet);
   return true;
 }
 
 port.on("elemhide.getSelectors", (message, sender) =>
 {
   let selectors = [];
   let emulatedPatterns = [];
-  let trace = devtools && devtools.hasPanel(sender.page);
+  let trace = devtools.hasPanel(sender.page.id);
   let inline = !userStyleSheetsSupported;
 
-  if (!checkWhitelisted(sender.page, sender.frame,
+  if (!checkWhitelisted(sender.page, sender.frame, null,
                         RegExpFilter.typeMap.DOCUMENT |
                         RegExpFilter.typeMap.ELEMHIDE))
   {
     let hostname = extractHostFromFrame(sender.frame);
-    let specificOnly = checkWhitelisted(sender.page, sender.frame,
+    let specificOnly = checkWhitelisted(sender.page, sender.frame, null,
                                         RegExpFilter.typeMap.GENERICHIDE);
 
     selectors = ElemHide.getSelectorsForDomain(
       hostname,
       specificOnly ? ElemHide.SPECIFIC_ONLY : ElemHide.ALL_MATCHING
     );
 
     for (let filter of ElemHideEmulation.getRulesForDomain(hostname))
       emulatedPatterns.push({selector: filter.selector, text: filter.text});
   }
@@ skipping 16 matching lines @@
     response.inlineEmulated = true;
 
   return response;
 });
 
 port.on("elemhide.injectSelectors", (message, sender) =>
 {
   updateFrameStyles(sender.page.id, sender.frame.id, message.selectors,
                     message.groupName, message.appendOnly);
 });