// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
/// @file hello_tutorial.cc
/// This example demonstrates loading, running and scripting a very simple NaCl
/// module. To load the NaCl module, the browser first looks for the
/// CreateModule() factory method (at the end of this file). It calls
/// CreateModule() once to load the module code. After the code is loaded,
/// CreateModule() is not called again.
///
/// Once the code is loaded, the browser calls the CreateInstance()
/// method on the object returned by CreateModule(). It calls CreateInstance()
/// each time it encounters an <embed> tag that references your NaCl module.
///
/// The browser can talk to your NaCl module via the postMessage() Javascript
/// function. When you call postMessage() on your NaCl module from the browser,
/// this becomes a call to the HandleMessage() method of your pp::Instance
/// subclass. You can send messages back to the browser by calling the
/// PostMessage() method on your pp::Instance. Note that these two methods
/// (postMessage() in Javascript and PostMessage() in C++) are asynchronous.
/// This means they return immediately - there is no waiting for the message
/// to be handled. This has implications in your program design, particularly
/// when mutating property values that are exposed to both the browser and the
/// NaCl module.
#include "ppapi/cpp/instance.h"
#include "ppapi/cpp/module.h"
#include "ppapi/cpp/var.h"
/// The Instance class. One of these exists for each instance of your NaCl
/// module on the web page. The browser will ask the Module object to create
/// a new Instance for each occurrence of the <embed> tag that has these
/// attributes:
/// src="hello_tutorial.nmf"
/// type="application/x-pnacl"
/// To communicate with the browser, you must override HandleMessage() to
/// receive messages from the browser, and use PostMessage() to send messages
/// back to the browser. Note that this interface is asynchronous.
class HelloTutorialInstance : public pp::Instance {
public:
/// The constructor creates the plugin-side instance.
/// @param[in] instance the handle to the browser-side plugin instance.
explicit HelloTutorialInstance(PP_Instance instance) : pp::Instance(instance)
{}
virtual ~HelloTutorialInstance() {}
/// Handler for messages coming in from the browser via postMessage(). The
/// @a var_message can contain be any pp:Var type; for example int, string
/// Array or Dictinary. Please see the pp:Var documentation for more details.
/// @param[in] var_message The message posted by the browser.
virtual void HandleMessage(const pp::Var& var_message) {
// TODO(sdk_user): 1. Make this function handle the incoming message.
}
};
/// The Module class. The browser calls the CreateInstance() method to create
/// an instance of your NaCl module on the web page. The browser creates a new
/// instance for each <embed> tag with type="application/x-pnacl".
class HelloTutorialModule : public pp::Module {
public:
HelloTutorialModule() : pp::Module() {}
virtual ~HelloTutorialModule() {}
/// Create and return a HelloTutorialInstance object.
/// @param[in] instance The browser-side instance.
/// @return the plugin-side instance.
virtual pp::Instance* CreateInstance(PP_Instance instance) {
return new HelloTutorialInstance(instance);
}
};
namespace pp {
/// Factory function called by the browser when the module is first loaded.
/// The browser keeps a singleton of this module. It calls the
/// CreateInstance() method on the object you return to make instances. There
/// is one instance per <embed> tag on the page. This is the main binding
/// point for your NaCl module with the browser.
Module* CreateModule() {
return new HelloTutorialModule();
}
} // namespace pp
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