Issue 6538, 6781 - Implement script parsing for snippets

lib/snippets.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/>.
  */
 
 "use strict";
 
 /**
  * @fileOverview Snippets implementation.
  */
 
-const {ElemHide} = require("./elemHide");
 const {Filter} = require("./filterClasses");
+
+const singleCharacterEscapes = new Map([
+  ["n", "\n"], ["r", "\r"], ["t", "\t"]
+]);
 
 let filters = new Set();
 
 /**
  * Container for snippet filters
  * @class
  */
 let Snippets = {
   /**
    * Removes all known filters
@@ skipping 17 matching lines @@
    * @param {SnippetFilter} filter
    */
   remove(filter)
   {
     filters.delete(filter.text);
   },
 
   /**
    * Returns a list of all scripts active on a particular domain
    * @param {string} domain
-   * @return {SnippetFilter[]}
+   * @return {string[]}
    */
   getScriptsForDomain(domain)
   {
     let result = [];
     for (let text of filters)
     {
       let filter = Filter.fromText(text);
-      if (filter.isActiveOnDomain(domain) &&
-          !ElemHide.getException(filter, domain))
-      {
-        result.push(filter);
-      }
+      if (filter.isActiveOnDomain(domain))
+        result.push(filter.script);
     }
     return result;
   }
 };
 
 exports.Snippets = Snippets;
 
 /**
  * Parses a script and returns a list of all its commands and their arguments
  * @param {string} script
  * @return {Array.<string[]>}
  */
 function parseScript(script)
 {
   let tree = [];
 
   let escape = false;
-  let literal = false;
+  let withinQuotes = false;
+
+  let unicodeEscape = null;
 
   let call = [];
   let argument = "";
 
-  for (let character of [...script.trim(), ";"])
+  for (let character of script.trim() + ";")
   {
-    if (escape)
+    if (unicodeEscape != null)
+    {
+      unicodeEscape += character;
+
+      if (unicodeEscape.length == 4)
+      {
+        let codePoint = parseInt(unicodeEscape, 16);
+        if (!isNaN(codePoint))
+          argument += String.fromCodePoint(codePoint);
+
+        unicodeEscape = null;
+      }
+    }
+    else if (escape)
     {
       escape = false;
 
-      argument += character;
+      if (character == "u")
+        unicodeEscape = "";
+      else
+        argument += singleCharacterEscapes.get(character) || character;
     }
     else if (character == "\\")
     {
       escape = true;
     }
     else if (character == "'")
     {
-      literal = !literal;
+      withinQuotes = !withinQuotes;
     }
-    else if (literal || character != ";" && !/\s/u.test(character))
+    else if (withinQuotes || character != ";" && !/\s/u.test(character))
     {
       argument += character;
     }
     else
     {
       if (argument)
       {
         call.push(argument);
         argument = "";
       }
 
       if (character == ";" && call.length > 0)
       {
         tree.push(call);
         call = [];
       }
     }
   }
 
   return tree;
 }
 
 exports.parseScript = parseScript;