Issue 6538, 6781 - Implement support for snippet filters

lib/filterClasses.js

Index: lib/filterClasses.js
===================================================================
--- a/lib/filterClasses.js
+++ b/lib/filterClasses.js
@@ -79,20 +79,20 @@
 
 /**
  * Cache for known filters, maps string representation to filter objects.
  * @type {Map.<string,Filter>}
  */
 Filter.knownFilters = new Map();
 
 /**
- * Regular expression that element hiding filters should match
+ * Regular expression that code injection filters should match
  * @type {RegExp}
  */
-Filter.elemhideRegExp = /^([^/*|@"!]*?)#([@?])?#(.+)$/;
+Filter.codeInjectionRegExp = /^([^/*|@"!]*?)#([@?$])?#(.+)$/;
 /**
  * Regular expression that RegExp filters specified as RegExps should match
  * @type {RegExp}
  */
 Filter.regexpRegExp = /^(@@)?\/.*\/(?:\$~?[\w-]+(?:=[^,\s]+)?(?:,~?[\w-]+(?:=[^,\s]+)?)*)?$/;
 /**
  * Regular expression that options on a RegExp filter should match
  * @type {RegExp}
@@ -112,34 +112,35 @@
  * @return {Filter}
  */
 Filter.fromText = function(text)
 {
   let filter = Filter.knownFilters.get(text);
   if (filter)
     return filter;
 
-  let match = (text.includes("#") ? Filter.elemhideRegExp.exec(text) : null);
+  let match = text.includes("#") ? Filter.codeInjectionRegExp.exec(text) : null;
   if (match)
   {
     let propsMatch;
     if (!match[2] &&
         (propsMatch = /\[-abp-properties=(["'])([^"']+)\1\]/.exec(match[3])))
     {
       // This is legacy CSS properties syntax, convert to current syntax
       let prefix = match[3].substr(0, propsMatch.index);
       let expression = propsMatch[2];
       let suffix = match[3].substr(propsMatch.index + propsMatch[0].length);
       return Filter.fromText(`${match[1]}#?#` +
           `${prefix}:-abp-properties(${expression})${suffix}`);
     }
 
-    filter = ElemHideBase.fromText(
-      text, match[1], match[2], match[3]
-    );
+    if (match[2] == "$")
+      filter = new SnippetFilter(text, match[1], match[3]);
+    else
+      filter = ElemHideBase.fromText(text, match[1], match[2], match[3]);
   }
   else if (text[0] == "!")
     filter = new CommentFilter(text);
   else
     filter = RegExpFilter.fromText(text);
 
   Filter.knownFilters.set(filter.text, filter);
   return filter;
@@ -179,22 +180,22 @@
 
   // Remove line breaks, tabs etc
   text = text.replace(/[^\S ]+/g, "");
 
   // Don't remove spaces inside comments
   if (/^ *!/.test(text))
     return text.trim();
 
-  // Special treatment for element hiding filters, right side is allowed to
+  // Special treatment for code injection filters, right side is allowed to
   // contain spaces
-  if (Filter.elemhideRegExp.test(text))
+  if (Filter.codeInjectionRegExp.test(text))
   {
-    let [, domains, separator, selector] = /^(.*?)(#[@?]?#?)(.*)$/.exec(text);
-    return domains.replace(/ +/g, "") + separator + selector.trim();
+    let [, domains, separator, code] = /^(.*?)(#[@?$]?#?)(.*)$/.exec(text);
+    return domains.replace(/ +/g, "") + separator + code.trim();
   }
 
   // For most regexp filters we strip all spaces, but $csp filter options
   // are allowed to contain single (non trailing) spaces.
   let strippedText = text.replace(/ +/g, "");
   if (!strippedText.includes("$") || !/\bcsp=/i.test(strippedText))
     return strippedText;
 
@@ -945,65 +946,84 @@
 }
 exports.WhitelistFilter = WhitelistFilter;
 
 WhitelistFilter.prototype = extend(RegExpFilter, {
   type: "whitelist"
 });
 
 /**
- * Base class for element hiding filters
+ * Base class for code injection filters
  * @param {string} text see Filter()
  * @param {string} [domains] Host names or domains the filter should be
  *                           restricted to
- * @param {string} selector   CSS selector for the HTML elements that should be
- *                            hidden
+ * @param {string} code      Code that should be injected
  * @constructor
  * @augments ActiveFilter
  */
-function ElemHideBase(text, domains, selector)
+function CodeInjectionFilter(text, domains, code)
 {
   ActiveFilter.call(this, text, domains || null);
 
   if (domains)
   {
-    this.selectorDomains = domains.replace(/,~[^,]+/g, "")
-                                  .replace(/^~[^,]+,?/, "").toLowerCase();
+    this.injectionDomains = domains.replace(/,~[^,]+/g, "")
+                                   .replace(/^~[^,]+,?/, "").toLowerCase();
   }
 
-  // Braces are being escaped to prevent CSS rule injection.
-  this.selector = selector.replace("{", "\\7B ").replace("}", "\\7D ");
+  this.code = code;
 }
-exports.ElemHideBase = ElemHideBase;
+exports.CodeInjectionFilter = CodeInjectionFilter;
 
-ElemHideBase.prototype = extend(ActiveFilter, {
+CodeInjectionFilter.prototype = extend(ActiveFilter, {
   /**
    * @see ActiveFilter.domainSeparator
    */
   domainSeparator: ",",
 
   /**
    * @see ActiveFilter.ignoreTrailingDot
    */
   ignoreTrailingDot: false,
 
   /**
    * Host names or domains the filter should be restricted to (can be null for
    * no restriction)
    * @type {string}
    */
-  selectorDomains: null,
+  injectionDomains: null,
+
   /**
-   * CSS selector for the HTML elements that should be hidden
+   * Code that should be injected
    * @type {string}
    */
-  selector: null
+  code: null
 });
 
 /**
+ * Base class for element hiding filters
+ * @param {string} text see Filter()
+ * @param {string} [domains] see CodeInjectionFilter()
+ * @param {string} selector  CSS selector for the HTML elements that should be
+ *                           hidden
+ * @constructor
+ * @augments CodeInjectionFilter
+ */
+function ElemHideBase(text, domains, selector)
+{
+  CodeInjectionFilter.call(this, text, domains, selector);
+
+  // Braces are being escaped to prevent CSS rule injection.
+  this.code = this.code.replace("{", "\\7B ").replace("}", "\\7D ");
+}
+exports.ElemHideBase = ElemHideBase;
+
+ElemHideBase.prototype = extend(CodeInjectionFilter, {});
+
+/**
  * Creates an element hiding filter from a pre-parsed text representation
  *
  * @param {string} text         same as in Filter()
  * @param {string?} domains
  *   domains part of the text representation
  * @param {string?} type
 *    rule type, either empty or @ (exception) or ? (emulation rule)
  * @param {string} selector     raw CSS selector
@@ -1082,8 +1102,26 @@
 {
   ElemHideBase.call(this, text, domains, selector);
 }
 exports.ElemHideEmulationFilter = ElemHideEmulationFilter;
 
 ElemHideEmulationFilter.prototype = extend(ElemHideBase, {
   type: "elemhideemulation"
 });
+
+/**
+ * Class for snippet filters
+ * @param {string} text see Filter()
+ * @param {string} [domains] see CodeInjectionFilter()
+ * @param {string} script    Script that should be executed
+ * @constructor
+ * @augments CodeInjectionFilter
+ */
+function SnippetFilter(text, domains, script)
+{
+  CodeInjectionFilter.call(this, text, domains, script);
+}
+exports.SnippetFilter = SnippetFilter;
+
+SnippetFilter.prototype = extend(CodeInjectionFilter, {
+  type: "snippet"
+});