Pepper UDP socket: buffer received packets in the plugin process to improve performance.

ppapi/proxy/resource_reply_thread_registrar.h

 // Copyright 2013 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_PROXY_RESOURCE_REPLY_THREAD_REGISTRAR_H_
 #define PPAPI_PROXY_RESOURCE_REPLY_THREAD_REGISTRAR_H_
 
 #include <map>
+#include <set>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/proxy/ppapi_proxy_export.h"
 
 
 namespace base {
 class MessageLoopProxy;
 }
 
+namespace IPC {
+class Message;
+}
+
 namespace ppapi {
 
 class TrackedCallback;
 
 namespace proxy {
 
+class ResourceMessageReplyParams;
+
 // ResourceReplyThreadRegistrar records the handling thread for
 // PpapiPluginMsg_ResourceReply messages.
 // This class is thread safe.
 class PPAPI_PROXY_EXPORT ResourceReplyThreadRegistrar
     : public base::RefCountedThreadSafe<ResourceReplyThreadRegistrar> {
  public:
   explicit ResourceReplyThreadRegistrar(
-      scoped_refptr<base::MessageLoopProxy> default_thread);
+      scoped_refptr<base::MessageLoopProxy> main_thread);
 
   // This method can only be called while holding the Pepper proxy lock; the
   // other methods can be called with/without the Pepper proxy lock.
   void Register(PP_Resource resource,
                 int32_t sequence_number,
                 scoped_refptr<TrackedCallback> reply_thread_hint);
 
+  // This results in Resource::OnReplyReceived() for the specified resource and
+  // message type to be called on the IO thread directly, while holding the
+  // Pepper proxy lock.
+  void HandleOnIOThread(PP_Resource resource, uint32 nested_msg_type);
+
   void Unregister(PP_Resource resource);
 
-  scoped_refptr<base::MessageLoopProxy> GetTargetThreadAndUnregister(
-      PP_Resource resource,
-      int32_t sequence_number);
+  // This method returns NULL if the target thread is the IO thread (because
+  // that is the thread on which this method is supposed to be called).
+  scoped_refptr<base::MessageLoopProxy> GetTargetThread(
+      const ResourceMessageReplyParams& reply_params,
+      const IPC::Message& nested_msg);
 
  private:
   friend class base::RefCountedThreadSafe<ResourceReplyThreadRegistrar>;
 
   typedef std::map<int32_t, scoped_refptr<base::MessageLoopProxy> >
-      SequenceNumberMap;
-  typedef std::map<PP_Resource, SequenceNumberMap> ResourceMap;
+      SequenceThreadMap;
+
+  struct ResourceInfo {
+    SequenceThreadMap thread_map;
+    std::set<uint32> io_thread_message_types;

[dmichael (off chromium), 2014/09/12 19:49:07]

I think it's likely that messages intended for the IO thread will always be
per-message-id, and not dependent on an individual PP_Resource. So it seems like
you could have this set separate, and check it before looking in the
ResourceMap. Might be simpler.

[yzshen1, 2014/09/15 20:59:39]

I agree. I have a question related to this in udp_socket_resource_base.cc. I
will make the change after the question is answered. Thanks!

+  };
+
+  typedef std::map<PP_Resource, ResourceInfo> ResourceMap;
 
   ~ResourceReplyThreadRegistrar();
 
   // The lock that protects the data members below.
   // Please note that we should never try to acquire the Pepper proxy lock while
   // holding |lock_|, otherwise we will cause deadlock.
   base::Lock lock_;
   ResourceMap map_;
-  scoped_refptr<base::MessageLoopProxy> default_thread_;
+  scoped_refptr<base::MessageLoopProxy> main_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceReplyThreadRegistrar);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif   // PPAPI_PROXY_RESOURCE_REPLY_THREAD_REGISTRAR_H_