net/spdy/spdy_buffer.h

   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_BUFFER_H_
   6 #define NET_SPDY_SPDY_BUFFER_H_
   7
   8 #include <cstddef>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback_forward.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "base/memory/scoped_ptr.h"
  15 #include "net/base/net_export.h"
  16
  17 namespace net {
  18
  19 class IOBuffer;
  20 class SpdyFrame;
  21
  22 // SpdyBuffer is a class to hold data read from or to be written to a
  23 // SPDY connection. It is similar to a DrainableIOBuffer but is not
  24 // ref-counted and will include a way to get notified when Consume()
  25 // is called.
  26 //
  27 // NOTE(akalin): This explicitly does not inherit from IOBuffer to
  28 // avoid the needless ref-counting and to avoid working around the
  29 // fact that IOBuffer member functions are not virtual.
  30 class NET_EXPORT_PRIVATE SpdyBuffer {
  31  public:
  32   // The source of a call to a ConsumeCallback.
  33   enum ConsumeSource {
  34     // Called via a call to Consume().
  35     CONSUME,
  36     // Called via the SpdyBuffer being destroyed.
  37     DISCARD
  38   };
  39
  40   // A Callback that gets called when bytes are consumed with the
  41   // (non-zero) number of bytes consumed and the source of the
  42   // consume. May be called any number of times with CONSUME as the
  43   // source followed by at most one call with DISCARD as the
  44   // source. The sum of the number of bytes consumed equals the total
  45   // size of the buffer.
  46   typedef base::Callback<void(size_t, ConsumeSource)> ConsumeCallback;
  47
  48   // Construct with the data in the given frame. Assumes that data is
  49   // owned by |frame| or outlives it.
  50   explicit SpdyBuffer(scoped_ptr<SpdyFrame> frame);
  51
  52   // Construct with a copy of the given raw data. |data| must be
  53   // non-NULL and |size| must be non-zero.
  54   SpdyBuffer(const char* data, size_t size);
  55
  56   // If there are bytes remaining in the buffer, triggers a call to
  57   // any consume callbacks with a DISCARD source.
  58   ~SpdyBuffer();
  59
  60   // Returns the remaining (unconsumed) data.
  61   const char* GetRemainingData() const;
  62
  63   // Returns the number of remaining (unconsumed) bytes.
  64   size_t GetRemainingSize() const;
  65
  66   // Add a callback to be called when bytes are consumed. The
  67   // ConsumeCallback should not do anything complicated; ideally it
  68   // should only update a counter. In particular, it must *not* cause
  69   // the SpdyBuffer itself to be destroyed.
  70   void AddConsumeCallback(const ConsumeCallback& consume_callback);
  71
  72   // Consume the given number of bytes, which must be positive but not
  73   // greater than GetRemainingSize().
  74   void Consume(size_t consume_size);
  75
  76   // Returns an IOBuffer pointing to the data starting at
  77   // GetRemainingData(). Use with care; the returned IOBuffer is not
  78   // updated when Consume() is called. However, it may still be used
  79   // past the lifetime of this object.
  80   //
  81   // This is used with Socket::Write(), which takes an IOBuffer* that
  82   // may be written to even after the socket itself is destroyed. (See
  83   // http://crbug.com/249725 .)
  84   IOBuffer* GetIOBufferForRemainingData();
  85
  86  private:
  87   void ConsumeHelper(size_t consume_size, ConsumeSource consume_source);
  88
  89   // Ref-count the passed-in SpdyFrame to support the semantics of
  90   // |GetIOBufferForRemainingData()|.
  91   typedef base::RefCountedData<scoped_ptr<SpdyFrame> > SharedFrame;
  92
  93   class SharedFrameIOBuffer;
  94
  95   const scoped_refptr<SharedFrame> shared_frame_;
  96   std::vector<ConsumeCallback> consume_callbacks_;
  97   size_t offset_;
  98
  99   DISALLOW_COPY_AND_ASSIGN(SpdyBuffer);
 100 };
 101
 102 }  // namespace net
 103
 104 #endif  // NET_SPDY_SPDY_BUFFER_H_