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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef PPAPI_HOST_RESOURCE_MESSAGE_HANDLER_H_
#define PPAPI_HOST_RESOURCE_MESSAGE_HANDLER_H_
#include "ppapi/c/pp_stdint.h"
#include "ppapi/host/ppapi_host_export.h"
namespace IPC {
class Message;
}
namespace ppapi {
namespace host {
struct HostMessageContext;
struct ReplyMessageContext;
// This is the base class of classes that can handle resource messages. It
// mainly exists at present to share code for checking replies to resource
// messages are valid.
class PPAPI_HOST_EXPORT ResourceMessageHandler {
public:
ResourceMessageHandler();
ResourceMessageHandler(const ResourceMessageHandler&) = delete;
ResourceMessageHandler& operator=(const ResourceMessageHandler&) = delete;
virtual ~ResourceMessageHandler();
// Called when this handler should handle a particular message. This should
// call into the the message handler implemented by subclasses (i.e.
// |OnResourceMessageReceived|) and perform any additional work necessary to
// handle the message (e.g. checking resource replies are valid). True is
// returned if the message is handled and false otherwise.
virtual bool HandleMessage(const IPC::Message& msg,
HostMessageContext* context) = 0;
// Send a resource reply message.
virtual void SendReply(const ReplyMessageContext& context,
const IPC::Message& msg) = 0;
protected:
// Runs the message handler and checks that a reply was sent if necessary.
void RunMessageHandlerAndReply(const IPC::Message& msg,
HostMessageContext* context);
// Handles messages associated with a given resource object. If the flags
// indicate that a response is required, the return value of this function
// will be sent as a resource message "response" along with the message
// specified in the reply of the context.
//
// You can do a response asynchronously by returning PP_OK_COMPLETIONPENDING.
// This will cause the reply to be skipped, and the class implementing this
// function will take responsibility for issuing the callback. The callback
// can be issued inside OnResourceMessageReceived before it returns, or at
// a future time.
//
// If you don't have a particular reply message, you can just ignore
// the reply in the message context. However, if you have a reply more than
// just the int32_t result code, set the reply to be the message of your
// choosing.
//
// The default implementation just returns PP_ERROR_NOTSUPPORTED.
virtual int32_t OnResourceMessageReceived(const IPC::Message& msg,
HostMessageContext* context);
};
} // namespace host
} // namespace ppapi
#endif // PPAPI_HOST_RESOURCE_MESSAGE_HANDLER_H_
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