/* Copyright (c) 2012 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.
*/
/**
* This file defines the <code>PPB_Messaging</code> interface implemented
* by the browser for sending messages to DOM elements associated with a
* specific module instance.
*/
[generate_thunk]
label Chrome {
M14 = 1.0
};
/**
* The <code>PPB_Messaging</code> interface is implemented by the browser
* and is related to sending messages to JavaScript message event listeners on
* the DOM element associated with specific module instance.
*/
interface PPB_Messaging {
/**
* PostMessage() asynchronously invokes any listeners for message events on
* the DOM element for the given module instance. A call to PostMessage()
* will not block while the message is processed.
*
* @param[in] instance A <code>PP_Instance</code> identifying one instance
* of a module.
* @param[in] message A <code>PP_Var</code> containing the data to be sent to
* JavaScript.
* <code>message</code> can be any <code>PP_Var</code> type except
* <code>PP_VARTYPE_OBJECT</code>. Array/Dictionary types are supported from
* Chrome M29 onward. All var types are copied when passing them to
* JavaScript.
*
* When passing array or dictionary <code>PP_Var</code>s, the entire reference
* graph will be converted and transferred. If the reference graph has cycles,
* the message will not be sent and an error will be logged to the console.
*
* Listeners for message events in JavaScript code will receive an object
* conforming to the HTML 5 <code>MessageEvent</code> interface.
* Specifically, the value of message will be contained as a property called
* data in the received <code>MessageEvent</code>.
*
* This messaging system is similar to the system used for listening for
* messages from Web Workers. Refer to
* <code>http://www.whatwg.org/specs/web-workers/current-work/</code> for
* further information.
*
* <strong>Example:</strong>
*
* @code
*
* <body>
* <object id="plugin"
* type="application/x-ppapi-postMessage-example"/>
* <script type="text/javascript">
* var plugin = document.getElementById('plugin');
* plugin.addEventListener("message",
* function(message) { alert(message.data); },
* false);
* </script>
* </body>
*
* @endcode
*
* The module instance then invokes PostMessage() as follows:
*
* @code
*
* char hello_world[] = "Hello world!";
* PP_Var hello_var = ppb_var_interface->VarFromUtf8(instance,
* hello_world,
* sizeof(hello_world));
* ppb_messaging_interface->PostMessage(instance, hello_var); // Copies var.
* ppb_var_interface->Release(hello_var);
*
* @endcode
*
* The browser will pop-up an alert saying "Hello world!"
*/
void PostMessage([in] PP_Instance instance, [in] PP_Var message);
};