| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Routines used to normalize arguments to messaging functions. |
| |
| function alignSendMessageArguments(args, hasOptionsArgument) { |
| // Align missing (optional) function arguments with the arguments that |
| // schema validation is expecting, e.g. |
| // extension.sendRequest(req) -> extension.sendRequest(null, req) |
| // extension.sendRequest(req, cb) -> extension.sendRequest(null, req, cb) |
| if (!args || !args.length) |
| return null; |
| var lastArg = args.length - 1; |
| |
| // responseCallback (last argument) is optional. |
| var responseCallback = null; |
| if (typeof args[lastArg] == 'function') |
| responseCallback = args[lastArg--]; |
| |
| var options = null; |
| if (hasOptionsArgument && lastArg >= 1) { |
| // options (third argument) is optional. It can also be ambiguous which |
| // argument it should match. If there are more than two arguments remaining, |
| // options is definitely present: |
| if (lastArg > 1) { |
| options = args[lastArg--]; |
| } else { |
| // Exactly two arguments remaining. If the first argument is a string, |
| // it should bind to targetId, and the second argument should bind to |
| // request, which is required. In other words, when two arguments remain, |
| // only bind options when the first argument cannot bind to targetId. |
| if (!(args[0] === null || typeof args[0] == 'string')) |
| options = args[lastArg--]; |
| } |
| } |
| |
| // request (second argument) is required. |
| var request = args[lastArg--]; |
| |
| // targetId (first argument, extensionId in the manifest) is optional. |
| var targetId = null; |
| if (lastArg >= 0) |
| targetId = args[lastArg--]; |
| |
| if (lastArg != -1) |
| return null; |
| if (hasOptionsArgument) |
| return [targetId, request, options, responseCallback]; |
| return [targetId, request, responseCallback]; |
| } |
| |
| exports.$set('alignSendMessageArguments', alignSendMessageArguments); |