Issue 5184 - Support Firefox-specific webRequest types

lib/requestBlocker.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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
@@ skipping 15 matching lines @@
 const {Prefs} = require("prefs");
 const {checkWhitelisted, getKey} = require("whitelisting");
 const {stringifyURL, extractHostFromFrame, isThirdParty} = require("url");
 const {port} = require("messaging");
 const devtools = require("devtools");
 
 // Chrome and Firefox (WebExtensions) can't distinguish between
 // OBJECT_SUBREQUEST and OBJECT requests.
 RegExpFilter.typeMap.OBJECT_SUBREQUEST = RegExpFilter.typeMap.OBJECT;
 
-let resourceTypeMapping = new Map([
-  ["beacon", "PING"],
-  ["imageset", "IMAGE"],
-  ["sub_frame", "SUBDOCUMENT"]
-]);

[Sebastian Noack, 2017/05/19 11:30:46]

How about using a mapping like below?

  let resourceTypes = new Map();
  for (let type in RegExpFilter.typeMap)
    resourceTypes.set(type.toLowerCase(), type);
  resourceTypes.set("beacon", "PING");
  resourceTypes.set("imageset", "IMAGE");
  resourceTypes.set("sub_frame", "SUBDOCUMENT");

Then in the onBeforeRequest handler:

  let mappedType = resourceTypes.get(type) || "OTHER";

  ...

  let filter = defaultMatcher.matchesAny(
    ...,
    RegExpFilter.typeMap[mappedType],
    ...
  );

  setTimeout(onBeforeRequestAsync, 0, ..., mappedType, ...);

This way we have two lookups again though, but:

* It seems to be overall less code.
* We don't have any duplicated logic (otherwise the code generating the
typeMasks mapping and the mapping for the devtools panel use redundant logic).
* We don't rely on chrome.webRequest.ResourceType. (Microsoft Edge actually
doesn't have ResourceType. It also seems to be generally more robust.)

What do you think?

[Manish Jethani, 2017/05/19 16:54:42]

Yes, that's two lookups now instead of one for the normal case, but it does
simplify the logic a bit. I've made the change.

+// Map of content types reported by the browser to the respecitve content types
+// used by Adblock Plus. Other content types are simply mapped to OTHER.
+let resourceTypes = new Map(function*()
+{
+  for (let type in RegExpFilter.typeMap)
+    yield [type.toLowerCase(), type];
 
-let typeMasks = new Map(
-  Object.keys(chrome.webRequest.ResourceType)
-  .map(typeKey => chrome.webRequest.ResourceType[typeKey])
-  .map(type => [type, RegExpFilter.typeMap[resourceTypeMapping.get(type)] ||
-                      RegExpFilter.typeMap[type.toUpperCase()] ||
-                      RegExpFilter.typeMap.OTHER])
-);
+  yield ["sub_frame", "SUBDOCUMENT"];
+
+  // Treat navigator.sendBeacon() the same as <a ping>, it's essentially the
+  // same concept - merely generalized.
+  yield ["beacon", "PING"];
+
+  // Treat <img srcset> and <picture> the same as other images.
+  yield ["imageset", "IMAGE"];
+}());
 
 function onBeforeRequestAsync(page, url, type, docDomain,
                               thirdParty, sitekey,
                               specificOnly, filter)
 {
   if (filter)
     FilterNotifier.emit("filter.hitCount", filter, 0, 0, page);
 
   if (devtools)
   {
-    let mappedType = resourceTypeMapping.get(type) || type.toUpperCase();
-    if (!RegExpFilter.typeMap[mappedType])
-      mappedType = "OTHER";
-
     devtools.logRequest(
-      page, url,
-      mappedType, docDomain,
+      page, url, type, docDomain,
       thirdParty, sitekey,
       specificOnly, filter
     );
   }
 }
 
 ext.webRequest.onBeforeRequest.addListener((url, type, page, frame) =>
 {
   if (checkWhitelisted(page, frame))
     return true;
 
   let urlString = stringifyURL(url);
   let docDomain = extractHostFromFrame(frame);
   let thirdParty = isThirdParty(url, docDomain);
   let sitekey = getKey(page, frame);
 
   let specificOnly = !!checkWhitelisted(
     page, frame, RegExpFilter.typeMap.GENERICBLOCK
   );
 
+  let mappedType = resourceTypes.get(type) || "OTHER";
+
   let filter = defaultMatcher.matchesAny(
-    urlString, typeMasks.get(type),
+    urlString, RegExpFilter.typeMap[mappedType],
     docDomain, thirdParty, sitekey, specificOnly
   );
 
   setTimeout(onBeforeRequestAsync, 0, page, urlString,
-                                      type, docDomain,
+                                      mappedType, docDomain,
                                       thirdParty, sitekey,
                                       specificOnly, filter);
 
   return !(filter instanceof BlockingFilter);
 });
 
 port.on("filters.collapse", (message, sender) =>
 {
   if (checkWhitelisted(sender.page, sender.frame))
     return false;
@@ skipping 79 matching lines @@
   if (msg.requestType in chrome.webRequest.ResourceType)
     return false;
 
   return ext.webRequest.onBeforeRequest._dispatch(
      new URL(msg.url),
      msg.requestType,
      sender.page,
      sender.frame
   ).includes(false);
 });