Add an explicitcancel option

filter.cc

@@ -322,6 +322,8 @@ void Filter::parseOption(const char *input, int len) {
     *pFilterOption = static_cast<FilterOption>(*pFilterOption | FOWebsocket);
   } else if (!strncmp(pStart, "important", len)) {
     *pFilterOption = static_cast<FilterOption>(*pFilterOption | FOImportant);
+  } else if (!strncmp(pStart, "explicitcancel", len)) {
+    *pFilterOption = static_cast<FilterOption>(*pFilterOption | FOExplicitCancel);
   } else {
     *pFilterOption = static_cast<FilterOption>(*pFilterOption | FOUnknown);
     std::string option(pStart, len);
@@ -445,12 +447,12 @@ bool Filter::matchesOptions(const char *input, FilterOption context,
   // blocking a the HTTP level, don't block here because we don't have enough
   // information
   if (context != FONoFilterOption) {
-    if ((filterOption & ~FOThirdParty) != FONoFilterOption
+    if ((filterOption & ~BehavioralFilterOnly) != FONoFilterOption
         && !(filterOption & FOResourcesOnly & context)) {
       return false;
     }
 
-    if ((antiFilterOption & ~FOThirdParty) != FONoFilterOption
+    if ((antiFilterOption & ~BehavioralFilterOnly) != FONoFilterOption
         && (antiFilterOption & FOResourcesOnly & context)) {
       return false;
     }

filter.h

@@ -5,7 +5,6 @@
 
 #ifndef FILTER_H_
 #define FILTER_H_
-
 #include <stdint.h>
 #include <string.h>
 #include "./base.h"
@@ -72,14 +71,18 @@ enum FilterOption {
   FOWebsocket = 0200000000,
   // important means to ignore all exception filters (those prefixed with @@).
   FOImportant = 0400000000,
+  // Cancel the request instead of using a 200 OK response
+  FOExplicitCancel = 01000000000,
 
   FOUnknown = 04000000000,
   FOResourcesOnly = FOScript|FOImage|FOStylesheet|FOObject|FOXmlHttpRequest|
     FOObjectSubrequest|FOSubdocument|FODocument|FOOther|FOXBL|FOFont|FOMedia|
     FOWebRTC|FOWebsocket|FOPing,
   FOUnsupportedSoSkipCheck = FOPopup|FOCSP|FOElemHide|FOGenericHide|
     FOGenericBlock|FOEmpty|FOUnknown,
-  FOUnsupportedButIgnore = FORedirect|FOImportant
+  // Non matching related filters, alters behavior
+  BehavioralFilterOnly = FORedirect|FOImportant|FOExplicitCancel|
+    FOThirdParty|FONotThirdParty
 };
 
 class Filter {