[SPDY] Refactor SpdySession's write queue

net/spdy/spdy_io_buffer.h

 // Copyright (c) 2012 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 NET_SPDY_SPDY_IO_BUFFER_H_
 #define NET_SPDY_SPDY_IO_BUFFER_H_
 
 #include "base/memory/ref_counted.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_export.h"
-#include "net/base/request_priority.h"
 
 namespace net {
 
 class SpdyStream;
 
-// A class for managing SPDY IO buffers.  These buffers need to be prioritized
-// so that the SpdySession sends them in the right order.  Further, they need
-// to track the SpdyStream which they are associated with so that incremental
-// completion of the IO can notify the appropriate stream of completion.
+// A class for managing SPDY write buffers.  These write buffers need
+// to track the SpdyStream which they are associated with so that the
+// session can activate the stream lazily and also notify the stream
+// on completion of the write.
 class NET_EXPORT_PRIVATE SpdyIOBuffer {
  public:
+  SpdyIOBuffer();
+
   // Constructor
   // |buffer| is the actual data buffer.
   // |size| is the size of the data buffer.
-  // |priority| is the priority of this buffer.
-  // |stream| is a pointer to the stream which is managing this buffer.
-  SpdyIOBuffer(IOBuffer* buffer, int size, RequestPriority priority,
-               SpdyStream* stream);
+  // |stream| is a pointer to the stream which is managing this buffer
+  // (can be NULL if the write is for the session itself).
+  SpdyIOBuffer(IOBuffer* buffer, int size, SpdyStream* stream);
+
   // Declare this instead of using the default so that we avoid needing to
   // include spdy_stream.h.
   SpdyIOBuffer(const SpdyIOBuffer& rhs);
-  SpdyIOBuffer();
+
   ~SpdyIOBuffer();
+
   // Declare this instead of using the default so that we avoid needing to
   // include spdy_stream.h.
   SpdyIOBuffer& operator=(const SpdyIOBuffer& rhs);
 
+  void Swap(SpdyIOBuffer* other);
+
+  void Release();
+
   // Accessors.
   DrainableIOBuffer* buffer() const { return buffer_; }
-  size_t size() const { return buffer_->size(); }
-  void release();
-  RequestPriority priority() const { return priority_; }
   const scoped_refptr<SpdyStream>& stream() const { return stream_; }
 
-  // Comparison operator to support sorting.
-  bool operator<(const SpdyIOBuffer& other) const {
-    if (priority_ != other.priority_)
-      return priority_ < other.priority_;
-    return position_ > other.position_;
-  }
-
  private:
   scoped_refptr<DrainableIOBuffer> buffer_;
-  RequestPriority priority_;
-  uint64 position_;
   scoped_refptr<SpdyStream> stream_;
-  static uint64 order_;  // Maintains a FIFO order for equal priorities.
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SPDY_IO_BUFFER_H_