| // 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. |
| |
| #ifndef PPAPI_CPP_MESSAGE_HANDLER_H_ |
| #define PPAPI_CPP_MESSAGE_HANDLER_H_ |
| |
| namespace pp { |
| |
| /// <code>MessageHandler</code> is an abstract base class that the plugin may |
| /// implement if it wants to receive messages from JavaScript on a background |
| /// thread when JavaScript invokes postMessage() or |
| /// postMessageAndAwaitResponse(). See pp::Instance::RegisterMessageHandler() |
| /// for usage. |
| class MessageHandler { |
| public: |
| virtual ~MessageHandler() {} |
| |
| /// Invoked as a result of JavaScript invoking postMessage() on the plugin's |
| /// DOM element. |
| /// |
| /// @param[in] instance An <code>InstanceHandle</code> identifying one |
| /// instance of a module. |
| /// @param[in] message_data A copy of the parameter that JavaScript provided |
| /// to postMessage(). |
| virtual void HandleMessage(pp::InstanceHandle instance, |
| const Var& message_data) = 0; |
| |
| /// Invoked as a result of JavaScript invoking postMessageAndAwaitResponse() |
| /// on the plugin's DOM element. |
| /// |
| /// NOTE: JavaScript execution is blocked during the duration of this call. |
| /// Hence, the plugin should respond as quickly as possible. For this reason, |
| /// blocking completion callbacks are disallowed while handling a blocking |
| /// message. |
| /// |
| /// @param[in] instance An <code>InstanceHandle</code> identifying one |
| /// instance of a module. |
| /// @param[in] message_data A copy of the parameter that JavaScript provided |
| /// to postMessage(). |
| /// @return Returns a pp::Var that is then copied to a JavaScript object |
| /// which is returned as the result of JavaScript's call of |
| /// postMessageAndAwaitResponse(). |
| virtual pp::Var HandleBlockingMessage(pp::InstanceHandle instance, |
| const Var& message_data) = 0; |
| |
| /// Invoked when this MessageHandler is no longer needed. After this, no more |
| /// calls will be made to this object. |
| /// |
| /// @param[in] instance An <code>InstanceHandle</code> identifying one |
| /// instance of a module. |
| virtual void WasUnregistered(pp::InstanceHandle instance) = 0; |
| }; |
| |
| } // namespace pp |
| |
| #endif // PPAPI_CPP_MESSAGE_HANDLER_H_ |