Issue 6538, 6781 - Implement support for snippet filters

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.

[Manish Jethani, 2018/04/26 13:19:17]

This is almost exactly like lib/elemHideEmulation.js

+ */
+
+const {ElemHide} = require("./elemHide");
+const {Filter} = require("./filterClasses");
+
+let filters = new Set();
+
+/**
+ * Container for snippet filters
+ * @class
+ */
+let Snippets = {
+  /**
+   * Removes all known filters
+   */
+  clear()
+  {
+    filters.clear();
+  },
+
+  /**
+   * Add a new snippet filter
+   * @param {SnippetFilter} filter
+   */
+  add(filter)
+  {
+    filters.add(filter.text);
+  },
+
+  /**
+   * Removes a snippet filter
+   * @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[]}
+   */
+  getScriptsForDomain(domain)
+  {
+    let result = [];
+    for (let text of filters)
+    {
+      let filter = Filter.fromText(text);
+      if (filter.isActiveOnDomain(domain) &&
+          !ElemHide.getException(filter, domain))

[Manish Jethani, 2018/04/26 13:19:16]

Note: We're using ElemHide exceptions here. I feel a little odd about this,
since SnippetFilter doesn't extend ElemHideBase. It's probably OK though. At
some point ElemHideException can be changed to CodeInjectionException.

+      {
+        result.push(filter);
+      }
+    }
+    return result;
+  }
+};
+
+exports.Snippets = Snippets;