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// Copyright 2015 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_PROXY_RESOURCE_MESSAGE_FILTER_H_
#define PPAPI_PROXY_RESOURCE_MESSAGE_FILTER_H_
#include "base/memory/ref_counted.h"
#include "ppapi/proxy/ppapi_proxy_export.h"
namespace IPC {
class Message;
}
namespace ppapi {
namespace proxy {
class ResourceMessageReplyParams;
// A ResourceMessageFilter lives on the IO thread and handles messages for a
// particular resource type. This is necessary in some cases where we want to
// reduce latency by doing some work on the IO thread rather than having to
// PostTask to the main Pepper thread.
//
// Note: In some cases we can rely on a reply being associated with a
// particular TrackedCallback, in which case we can dispatch directly to the
// TrackedCallback's thread. See ReplyThreadRegistrar. That should be the first
// choice for avoiding an unecessary jump to the main-thread.
//
// ResourceMessageFilter is for cases where there is not a one-to-one
// relationship between a reply message and a TrackedCallback. For example, for
// UDP Socket resources, the browser pushes data to the plugin even when the
// plugin does not have a pending callback. We can't use the
// ReplyThreadRegistrar, because data may arrive when there's not yet a
// TrackedCallback to tell us what thread to use. So instead, we define a
// UDPSocketFilter which accepts and queues UDP data on the IO thread.
class PPAPI_PROXY_EXPORT ResourceMessageFilter
: public base::RefCountedThreadSafe<ResourceMessageFilter> {
public:
virtual bool OnResourceReplyReceived(
const ResourceMessageReplyParams& reply_params,
const IPC::Message& nested_msg) = 0;
protected:
friend class base::RefCountedThreadSafe<ResourceMessageFilter>;
virtual ~ResourceMessageFilter() {}
};
} // namespace proxy
} // namespace ppapi
#endif // PPAPI_PROXY_RESOURCE_MESSAGE_FILTER_H_
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