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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef NET_SPDY_SPDY_WRITE_QUEUE_H_
      6 #define NET_SPDY_SPDY_WRITE_QUEUE_H_
      7 
      8 #include <deque>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "base/memory/weak_ptr.h"
     13 #include "net/base/net_export.h"
     14 #include "net/base/request_priority.h"
     15 #include "net/spdy/spdy_protocol.h"
     16 
     17 namespace net {
     18 
     19 class SpdyBuffer;
     20 class SpdyBufferProducer;
     21 class SpdyStream;
     22 
     23 // A queue of SpdyBufferProducers to produce frames to write. Ordered
     24 // by priority, and then FIFO.
     25 class NET_EXPORT_PRIVATE SpdyWriteQueue {
     26  public:
     27   SpdyWriteQueue();
     28   ~SpdyWriteQueue();
     29 
     30   // Returns whether there is anything in the write queue,
     31   // i.e. whether the next call to Dequeue will return true.
     32   bool IsEmpty() const;
     33 
     34   // Enqueues the given frame producer of the given type at the given
     35   // priority associated with the given stream, which may be NULL if
     36   // the frame producer is not associated with a stream. If |stream|
     37   // is non-NULL, its priority must be equal to |priority|, and it
     38   // must remain non-NULL until the write is dequeued or removed.
     39   void Enqueue(RequestPriority priority,
     40                SpdyFrameType frame_type,
     41                scoped_ptr<SpdyBufferProducer> frame_producer,
     42                const base::WeakPtr<SpdyStream>& stream);
     43 
     44   // Dequeues the frame producer with the highest priority that was
     45   // enqueued the earliest and its associated stream. Returns true and
     46   // fills in |frame_type|, |frame_producer|, and |stream| if
     47   // successful -- otherwise, just returns false.
     48   bool Dequeue(SpdyFrameType* frame_type,
     49                scoped_ptr<SpdyBufferProducer>* frame_producer,
     50                base::WeakPtr<SpdyStream>* stream);
     51 
     52   // Removes all pending writes for the given stream, which must be
     53   // non-NULL.
     54   void RemovePendingWritesForStream(const base::WeakPtr<SpdyStream>& stream);
     55 
     56   // Removes all pending writes for streams after |last_good_stream_id|
     57   // and streams with no stream id.
     58   void RemovePendingWritesForStreamsAfter(SpdyStreamId last_good_stream_id);
     59 
     60   // Removes all pending writes.
     61   void Clear();
     62 
     63  private:
     64   // A struct holding a frame producer and its associated stream.
     65   struct PendingWrite {
     66     SpdyFrameType frame_type;
     67     // This has to be a raw pointer since we store this in an STL
     68     // container.
     69     SpdyBufferProducer* frame_producer;
     70     base::WeakPtr<SpdyStream> stream;
     71     // Whether |stream| was non-NULL when enqueued.
     72     bool has_stream;
     73 
     74     PendingWrite();
     75     PendingWrite(SpdyFrameType frame_type,
     76                  SpdyBufferProducer* frame_producer,
     77                  const base::WeakPtr<SpdyStream>& stream);
     78     ~PendingWrite();
     79   };
     80 
     81   bool removing_writes_;
     82 
     83   // The actual write queue, binned by priority.
     84   std::deque<PendingWrite> queue_[NUM_PRIORITIES];
     85 
     86   DISALLOW_COPY_AND_ASSIGN(SpdyWriteQueue);
     87 };
     88 
     89 }  // namespace net
     90 
     91 #endif  // NET_SPDY_SPDY_WRITE_QUEUE_H_
     92