Issue 5184 - Support Firefox-specific webRequest types

lib/requestBlocker.js

Index: lib/requestBlocker.js
===================================================================
--- a/lib/requestBlocker.js
+++ b/lib/requestBlocker.js
@@ -24,19 +24,37 @@
 const {defaultMatcher} = require("matcher");
 const {FilterNotifier} = require("filterNotifier");
 const {Prefs} = require("prefs");
 const {checkWhitelisted, getKey} = require("whitelisting");
 const {stringifyURL, extractHostFromFrame, isThirdParty} = require("url");
 const {port} = require("messaging");
 const devtools = require("devtools");
 
-// Chrome can't distinguish between OBJECT_SUBREQUEST and OBJECT requests.
+// Chrome and Firefox (WebExtensions) can't distinguish between
+// OBJECT_SUBREQUEST and OBJECT requests.
 RegExpFilter.typeMap.OBJECT_SUBREQUEST = RegExpFilter.typeMap.OBJECT;
 
+// 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];
+
+  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)
@@ -58,23 +76,25 @@
   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, RegExpFilter.typeMap[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) =>
 {