Issue 3671 - Split out contentBlockerList API

lib/contentBlockerList.js

Index: lib/contentBlockerList.js
diff --git a/lib/contentBlockerList.js b/lib/contentBlockerList.js
new file mode 100644
index 0000000000000000000000000000000000000000..3ecca5f0b8f9f44abb803f9691f56a9ac8e8d56f
--- /dev/null
+++ b/lib/contentBlockerList.js
@@ -0,0 +1,394 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-2016 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/>.
+ */
+
+/** @module contentBlockerList */
+
+"use strict";
+
+let filterClasses = require("filterClasses");
+let getBaseDomain = require("urlHelpers").getBaseDomain;
+let punycode = require("punycode");
+
+const selectorLimit = 5000;
+const typeMap = filterClasses.RegExpFilter.typeMap;
+
+function parseDomains(domains, included, excluded)
+{
+  for (let domain in domains)
+  {
+    if (domain != "")
+    {
+      let enabled = domains[domain];
+      domain = punycode.toASCII(domain.toLowerCase());
+
+      if (!enabled)
+        excluded.push(domain);
+      else if (!domains[""])
+        included.push(domain);
+    }
+  }
+}
+
+function escapeRegExp(s)
+{
+  return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+}
+
+function matchDomain(domain)
+{
+  return "^https?://([^/:]*\\.)?" + escapeRegExp(domain) + "[/:]";
+}
+
+function convertElemHideFilter(filter, elemhideSelectorExceptions)
+{
+  let included = [];
+  let excluded = [];
+  let rules = [];
+
+  parseDomains(filter.domains, included, excluded);
+
+  if (excluded.length == 0 && !(filter.selector in elemhideSelectorExceptions))
+    return {matchDomains: included.map(matchDomain), selector: filter.selector};
+}
+
+function toRegExp(text)
+{
+  let result = [];
+  let lastIndex = text.length - 1;
+
+  for (let i = 0; i < text.length; i++)
+  {
+    let c = text[i];
+
+    switch (c)
+    {
+      case "*":
+        if (result.length > 0 && i < lastIndex && text[i + 1] != "*")
+          result.push(".*");
+        break;
+      case "^":
+        if (i < lastIndex)
+          result.push(".");
+        break;
+      case "|":
+        if (i == 0)
+        {
+          result.push("^");
+          break;
+        }
+        if (i == lastIndex)
+        {
+          result.push("$");
+          break;
+        }
+        if (i == 1 && text[0] == "|")
+        {
+          result.push("https?://");
+          break;
+        }
+      case ".": case "+": case "?": case "$":
+      case "{": case "}": case "(": case ")":
+      case "[": case "]": case "\\":
+        result.push("\\");

[Sebastian Noack, 2016/02/22 17:35:28]

Nit: Perhaps we should change the code here to:

  result.push("\\", c);
  break;

The missing drop-through here might be a little sneaky and hard to spot when
reading the code. Plus that way we have one function call less, when escaping
charterers. But I wouldn't insist. 

[Sebastian Noack, 2016/02/22 17:37:31]

s/missing drop-through/missing break/

[kzar, 2016/02/22 18:09:29]

Done.

+      default:
+        result.push(c);
+    }
+  }
+
+  return result.join("");
+}
+
+function getRegExpSource(filter)
+{
+  let source = toRegExp(filter.regexpSource.replace(
+    // Safari expects punycode, filter lists use unicode
+    /^(\|\||\|?https?:\/\/)([\w\-.*\u0080-\uFFFF]+)/i,
+    function (match, prefix, domain)
+    {
+      return prefix + punycode.toASCII(domain);
+    }
+  ));
+
+  // Limit rules to to HTTP(S) URLs
+  if (!/^(\^|http)/i.test(source))
+    source = "^https?://.*" + source;
+
+  return source;
+}
+
+function getResourceTypes(filter)
+{
+  let types = [];
+
+  if (filter.contentType & typeMap.IMAGE)
+    types.push("image");
+  if (filter.contentType & typeMap.STYLESHEET)
+    types.push("style-sheet");
+  if (filter.contentType & typeMap.SCRIPT)
+    types.push("script");
+  if (filter.contentType & typeMap.FONT)
+    types.push("font");
+  if (filter.contentType & (typeMap.MEDIA | typeMap.OBJECT))
+    types.push("media");
+  if (filter.contentType & typeMap.POPUP)
+    types.push("popup");
+  if (filter.contentType & (typeMap.XMLHTTPREQUEST |
+                            typeMap.OBJECT_SUBREQUEST |
+                            typeMap.PING | typeMap.OTHER))

[Sebastian Noack, 2016/02/22 17:35:28]

Nit: I think it reads slightly better, and looks more consistent, if all types
are aligned. But I wouldn't insist.

[kzar, 2016/02/22 18:09:29]

Done.

+    types.push("raw");
+  if (filter.contentType & typeMap.SUBDOCUMENT)
+    types.push("document");
+
+  return types;
+}
+
+function addDomainPrefix(domains)
+{
+  let result = [];
+
+  for (let domain of domains)
+  {
+    result.push(domain);
+
+    if (getBaseDomain(domain) == domain)
+      result.push("www." + domain);
+  }
+
+  return result;
+}
+
+function convertFilter(filter, action, withResourceTypes)
+{
+  let trigger = {"url-filter": getRegExpSource(filter)};
+  let included = [];
+  let excluded = [];
+
+  parseDomains(filter.domains, included, excluded);
+
+  if (withResourceTypes)
+    trigger["resource-type"] = getResourceTypes(filter);
+  if (filter.thirdParty != null)
+    trigger["load-type"] = [filter.thirdParty ? "third-party" : "first-party"];
+
+  if (included.length > 0)
+    trigger["if-domain"] = addDomainPrefix(included);
+  else if (excluded.length > 0)
+    trigger["unless-domain"] = addDomainPrefix(excluded);
+
+  return {trigger: trigger, action: {type: action}};
+}
+
+function hasNonASCI(obj)
+{
+  if (typeof obj == "string")
+  {
+    if (/[^\x00-\x7F]/.test(obj))
+      return true;
+  }
+
+  if (typeof obj == "object")
+  {
+    if (obj instanceof Array)
+      for (let item of obj)
+        if (hasNonASCI(item))
+          return true;
+
+    let names = Object.getOwnPropertyNames(obj);
+    for (let name of names)
+      if (hasNonASCI(obj[name]))
+        return true;
+  }
+
+  return false;
+}
+
+function convertIDSelectorsToAttributeSelectors(selector)
+{
+  // First we figure out where all the IDs are
+  let sep = "";
+  let start = null;
+  let positions = [];
+  for (let i = 0; i < selector.length; i++)
+  {
+    let chr = selector[i];
+
+    if (chr == "\\")        // ignore escaped characters
+      i++;
+    else if (chr == sep)    // don't match IDs within quoted text
+      sep = "";             // e.g. [attr="#Hello"]
+    else if (sep == "")
+    {
+      if (chr == '"' || chr == "'")
+        sep = chr;
+      else if (start == null)  // look for the start of an ID
+      {
+        if (chr == "#")
+          start = i;
+      }
+      else if (chr != "-" && chr != "_" &&
+               (chr < "0" ||
+                chr > "9" && chr < "A" ||
+                chr > "Z" && chr < "a" ||
+                chr > "z" && chr < "\x80")) // look for the end of the ID
+      {
+        positions.push({start: start, end: i});
+        start = null;
+      }
+    }
+  }
+  if (start != null)
+    positions.push({start: start, end: selector.length});
+
+  // Now replace them all with the [id="someID"] form
+  let newSelector = [];
+  let i = 0;
+  for (let pos of positions)
+  {
+    newSelector.push(selector.substring(i, pos.start));
+    newSelector.push('[id=', selector.substring(pos.start + 1, pos.end), ']');
+    i = pos.end;
+  }
+  newSelector.push(selector.substring(i));
+
+  return newSelector.join("");
+}
+
+let ContentBlockerList =
+/**
+ * Create a new Adblock Plus filter to content blocker list converter
+ *
+ * @constructor
+ */
+exports.ContentBlockerList = function ()
+{
+  this.requestFilters = [];
+  this.requestExceptions = [];
+  this.elemhideFilters = [];
+  this.elemhideExceptions =  [];
+  this.elemhideSelectorExceptions = new Map();
+};
+
+ContentBlockerList.prototype = {};

[Sebastian Noack, 2016/02/22 17:35:28]

There is no need to set the prototype to an empty object. Each function
automatically gets a prototype object setup.

[kzar, 2016/02/22 18:09:29]

Done.

+
+/**
+ * Add Adblock Plus filter to be converted
+ *
+ * @param {Filter} filter Filter to convert
+ */
+ContentBlockerList.prototype.addFilter = function(filter)
+{
+  if (filter.sitekeys)
+    return;
+  if (filter instanceof filterClasses.RegExpFilter && !filter.regexpSource)
+    return;
+
+  if (filter instanceof filterClasses.BlockingFilter)
+    this.requestFilters.push(filter);
+
+  if (filter instanceof filterClasses.WhitelistFilter)
+  {
+    if (filter.contentType & (typeMap.IMAGE
+                              | typeMap.STYLESHEET
+                              | typeMap.SCRIPT
+                              | typeMap.FONT
+                              | typeMap.MEDIA
+                              | typeMap.POPUP
+                              | typeMap.OBJECT
+                              | typeMap.OBJECT_SUBREQUEST
+                              | typeMap.XMLHTTPREQUEST
+                              | typeMap.PING
+                              | typeMap.SUBDOCUMENT
+                              | typeMap.OTHER))
+      this.requestExceptions.push(filter);
+
+      if (filter.contentType & typeMap.ELEMHIDE)
+        this.elemhideExceptions.push(filter);
+  }
+
+  if (filter instanceof filterClasses.ElemHideFilter)
+    this.elemhideFilters.push(filter);
+
+  if (filter instanceof filterClasses.ElemHideException)
+  {
+    let domains = this.elemhideSelectorExceptions[filter.selector];
+    if (!domains)
+      domains = this.elemhideSelectorExceptions[filter.selector] = [];
+
+    parseDomains(filter.domains, domains, []);
+  }
+};
+
+/**
+ * Generate content blocker list for all filters that were added
+ *
+ * @returns   {Filter}   filter    Filter to convert
+ */
+ContentBlockerList.prototype.generateRules = function(filter)
+{
+  let rules = [];
+
+  function addRule(rule)
+  {
+    if (!hasNonASCI(rule))
+      rules.push(rule);
+  }
+
+  let groupedElemhideFilters = new Map();
+  for (let filter of this.elemhideFilters)
+  {
+    let result = convertElemHideFilter(filter, this.elemhideSelectorExceptions);
+    if (!result)
+      continue;
+
+    if (result.matchDomains.length == 0)
+      result.matchDomains = ["^https?://"];
+
+    for (let matchDomain of result.matchDomains)
+    {
+      let group = groupedElemhideFilters.get(matchDomain) || [];
+      group.push(result.selector);
+      groupedElemhideFilters.set(matchDomain, group);
+    }
+  }
+
+  groupedElemhideFilters.forEach((selectors, matchDomain) =>
+  {
+    while (selectors.length)
+    {
+      let selector = selectors.splice(0, selectorLimit).join(", ");
+
+      // As of Safari 9.0 element IDs are matched as lowercase. We work around
+      // this by converting to the attribute format [id="elementID"]
+      selector = convertIDSelectorsToAttributeSelectors(selector);
+
+      addRule({
+        trigger: {"url-filter": matchDomain},
+        action: {type: "css-display-none",
+                 selector: selector}
+      });
+    }
+  });
+
+  for (let filter of this.elemhideExceptions)
+    addRule(convertFilter(filter, "ignore-previous-rules", false));
+  for (let filter of this.requestFilters)
+    addRule(convertFilter(filter, "block", true));
+  for (let filter of this.requestExceptions)
+    addRule(convertFilter(filter, "ignore-previous-rules", true));
+
+  return rules;
+};