net/quic/quic_write_blocked_list.h

   1 // Copyright 2014 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_QUIC_QUIC_WRITE_BLOCKED_LIST_H_
   6 #define NET_QUIC_QUIC_WRITE_BLOCKED_LIST_H_
   7
   8 #include "net/base/net_export.h"
   9 #include "net/quic/quic_protocol.h"
  10 #include "net/spdy/write_blocked_list.h"
  11
  12 namespace net {
  13
  14 // Keeps tracks of the QUIC streams that have data to write, sorted by
  15 // priority.  QUIC stream priority order is:
  16 // Crypto stream > Headers stream > Data streams by requested priority.
  17 class NET_EXPORT_PRIVATE QuicWriteBlockedList {
  18  private:
  19   typedef WriteBlockedList<QuicStreamId> QuicWriteBlockedListBase;
  20
  21  public:
  22   static const QuicPriority kHighestPriority;
  23   static const QuicPriority kLowestPriority;
  24
  25   QuicWriteBlockedList();
  26   ~QuicWriteBlockedList();
  27
  28   bool HasWriteBlockedStreams() const {
  29     return crypto_stream_blocked_ ||
  30         headers_stream_blocked_ ||
  31         base_write_blocked_list_.HasWriteBlockedStreams();
  32   }
  33
  34   size_t NumBlockedStreams() const {
  35     size_t num_blocked = base_write_blocked_list_.NumBlockedStreams();
  36     if (crypto_stream_blocked_) {
  37       ++num_blocked;
  38     }
  39     if (headers_stream_blocked_) {
  40       ++num_blocked;
  41     }
  42
  43     return num_blocked;
  44   }
  45
  46   QuicStreamId PopFront() {
  47     if (crypto_stream_blocked_) {
  48       crypto_stream_blocked_ = false;
  49       return kCryptoStreamId;
  50     } else if (headers_stream_blocked_) {
  51       headers_stream_blocked_ = false;
  52       return kHeadersStreamId;
  53     } else {
  54       SpdyPriority priority =
  55           base_write_blocked_list_.GetHighestPriorityWriteBlockedList();
  56       return base_write_blocked_list_.PopFront(priority);
  57     }
  58   }
  59
  60   void PushBack(QuicStreamId stream_id, QuicPriority priority) {
  61     if (stream_id == kCryptoStreamId) {
  62       DCHECK_EQ(kHighestPriority, priority);
  63       // TODO(avd) Add DCHECK(!crypto_stream_blocked_)
  64       crypto_stream_blocked_ = true;
  65     } else if (stream_id == kHeadersStreamId) {
  66       DCHECK_EQ(kHighestPriority, priority);
  67       // TODO(avd) Add DCHECK(!headers_stream_blocked_);
  68       headers_stream_blocked_ = true;
  69     } else {
  70       base_write_blocked_list_.PushBack(
  71           stream_id, static_cast<SpdyPriority>(priority));
  72     }
  73   }
  74
  75  private:
  76   QuicWriteBlockedListBase base_write_blocked_list_;
  77   bool crypto_stream_blocked_;
  78   bool headers_stream_blocked_;
  79
  80   DISALLOW_COPY_AND_ASSIGN(QuicWriteBlockedList);
  81 };
  82
  83 }  // namespace net
  84
  85
  86 #endif  // NET_QUIC_QUIC_WRITE_BLOCKED_LIST_H_