A proposal for an initial postMessage interface. This will allow JavaScript ...

ppapi/examples/scripting/post_message.cc

+// Copyright (c) 2011 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.
+
+#include <algorithm>
+
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/var.h"
+
+// This is a simple C++ Pepper plugin that demonstrates HandleMessage and
+// PostMessage.
+
+// This object represents one time the page says <embed>.
+class MyInstance : public pp::Instance {
+ public:
+  explicit MyInstance(PP_Instance instance) : pp::Instance(instance) {}
+  virtual ~MyInstance() {}
+  virtual void HandleMessage(const pp::Var& message_data);
+};
+
+// HandleMessage gets invoked when postMessage is called on the DOM element
+// associated with this plugin instance.
+// In this case, if we are given a string, we'll post a message back to
+// JavaScript indicating whether or not that string is a palindrome.
+void MyInstance::HandleMessage(const pp::Var& message_data) {
+  if (message_data.is_string()) {
+    std::string string_copy(message_data.AsString());
+    std::reverse(string_copy.begin(), string_copy.end());
+    bool is_palindrome(message_data.AsString() == string_copy);
+
+    PostMessage(pp::Var(is_palindrome));
+  }
+}
+
+// This object is the global object representing this plugin library as long
+// as it is loaded.
+class MyModule : public pp::Module {
+ public:
+  MyModule() : pp::Module() {}
+  virtual ~MyModule() {}
+
+  // Override CreateInstance to create your customized Instance object.
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new MyInstance(instance);
+  }
+};
+
+namespace pp {
+
+// Factory function for your specialization of the Module object.
+Module* CreateModule() {
+  return new MyModule();
+}
+
+}  // namespace pp
+