Issue 5028 - Use browser namespace

polyfill.js

Index: polyfill.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/polyfill.js
@@ -0,0 +1,89 @@
+/*
+ * 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";
+
+// Set up a "browser" namespace with a promisified version of the extension
+// APIs on Chrome and Edge.
+if (typeof browser == "undefined" || typeof chrome == "undefined" ||
+    typeof chrome != "undefined" && !("extension" in chrome))
+{
+  const callbackApi = new Set([
+    "create"

[Manish Jethani, 2017/10/11 03:26:44]

Right now only covers tabs.create

+  ]);
+
+  if (typeof browser == "undefined")
+    window.browser = chrome;
+
+  window.browser = new Proxy(browser, {
+    get(target, property)
+    {
+      let value = target[property];
+
+      // If this is a non-null object and the name does not begin with "on"
+      // (e.g. "onUpdated"), wrap it into a proxy.
+      if (typeof value == "object" && value != null &&
+          !/^on[A-Z]/.test(property))
+      {
+        return new Proxy(value, this);
+      }
+
+      // If this is one of the known API functions that take an optional
+      // callback as the last argument, wrap it into a special proxy with a
+      // promise-based interface.
+      if (typeof value == "function" && callbackApi.has(property))
+      {
+        return new Proxy(value, {
+          apply(target, thisArg, argumentsList)
+          {
+            // If the caller has already supplied a callback, just call and
+            // return.
+            if (typeof argumentsList[argumentsList.length - 1] == "function")
+              return target.apply(thisArg, argumentsList);
+
+            // Wrap the API call into a promise.
+            return new Promise((resolve, reject) =>
+            {
+              target.apply(thisArg, [
+                ...argumentsList,
+                result =>
+                {
+                  let error = browser.runtime.lastError;
+                  if (error)
+                    reject(error);
+                  else
+                    resolve(result);
+                }
+              ]);
+            });
+          }
+        });
+      }
+
+      return value;
+    }
+  });
+}
+
+// Workaround since HTMLCollection, NodeList, StyleSheetList, and CSSRuleList
+// didn't have iterator support before Chrome 51.
+// https://bugs.chromium.org/p/chromium/issues/detail?id=401699
+for (let object of [HTMLCollection, NodeList, StyleSheetList, CSSRuleList])
+{
+  if (!(Symbol.iterator in object.prototype))
+    object.prototype[Symbol.iterator] = Array.prototype[Symbol.iterator];
+}