Issue 491 - Validate custom filters

lib/filterValidation.js

Index: lib/filterValidation.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/lib/filterValidation.js
@@ -0,0 +1,84 @@
+/*
+ * This file is part of Adblock Plus <http://adblockplus.org/>,
+ * Copyright (C) 2006-2014 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/>.
+ */
+
+let {Filter, InvalidFilter, ElemHideBase} = require("filterClasses");
+
+function parseFilter(text, ignore_headers)
+{
+  text = Filter.normalize(text);
+  if (!text)
+    return null;
+
+  if (text[0] == "[")
+  {
+    if (ignore_headers)
+      return null;
+
+    throw ext.i18n.getMessage("unexpected_filter_list_header");
+  }
+
+  let filter = Filter.fromText(text);
+
+  if (filter instanceof InvalidFilter)
+    throw filter.reason;
+
+  if (filter instanceof ElemHideBase)
+  {
+    let style = document.createElement("style");
+    document.documentElement.appendChild(style);
+    let sheet = style.sheet;
+    document.documentElement.removeChild(style);
+
+    try
+    {
+      document.querySelector(filter.selector);
+      sheet.insertRule(filter.selector + "{}", 0);
+    }
+    catch (error)
+    {
+      throw ext.i18n.getMessage("invalid_css_selector", "'" + filter.selector + "'");
+    }
+  }
+
+  return filter;
+}
+exports.parseFilter = parseFilter;
+
+function parseFilters(text, ignore_headers)
+{
+  let lines = text.split("\n");
+  let filters = [];
+
+  for (let i = 0; i < lines.length; i++)
+  {
+    let filter;
+    try
+    {
+      filter = parseFilter(lines[i], ignore_headers);
+    }
+    catch (error)
+    {
+      throw ext.i18n.getMessage("line", (i + 1).toString()) + ": " + error;
+    }
+
+    if (filter)
+      filters.push(filter);
+  }
+
+  return filters;
+}
+exports.parseFilters = parseFilters;