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 <set>
   9
  10 #include "net/base/net_export.h"
  11 #include "net/quic/quic_protocol.h"
  12 #include "net/spdy/write_blocked_list.h"
  13
  14 namespace net {
  15
  16 // Keeps tracks of the QUIC streams that have data to write, sorted by
  17 // priority.  QUIC stream priority order is:
  18 // Crypto stream > Headers stream > Data streams by requested priority.
  19 class NET_EXPORT_PRIVATE QuicWriteBlockedList {
  20  private:
  21   typedef WriteBlockedList<QuicStreamId> QuicWriteBlockedListBase;
  22
  23  public:
  24   static const QuicPriority kHighestPriority;
  25   static const QuicPriority kLowestPriority;
  26
  27   QuicWriteBlockedList();
  28   ~QuicWriteBlockedList();
  29
  30   bool HasWriteBlockedDataStreams() const {
  31     return base_write_blocked_list_.HasWriteBlockedStreams();
  32   }
  33
  34   bool HasWriteBlockedCryptoOrHeadersStream() const {
  35     return crypto_stream_blocked_ || headers_stream_blocked_;
  36   }
  37
  38   size_t NumBlockedStreams() const {
  39     size_t num_blocked = base_write_blocked_list_.NumBlockedStreams();
  40     if (crypto_stream_blocked_) {
  41       ++num_blocked;
  42     }
  43     if (headers_stream_blocked_) {
  44       ++num_blocked;
  45     }
  46
  47     return num_blocked;
  48   }
  49
  50   QuicStreamId PopFront() {
  51     if (crypto_stream_blocked_) {
  52       crypto_stream_blocked_ = false;
  53       return kCryptoStreamId;
  54     }
  55
  56     if (headers_stream_blocked_) {
  57       headers_stream_blocked_ = false;
  58       return kHeadersStreamId;
  59     }
  60
  61     SpdyPriority priority =
  62         base_write_blocked_list_.GetHighestPriorityWriteBlockedList();
  63     QuicStreamId id = base_write_blocked_list_.PopFront(priority);
  64     blocked_streams_.erase(id);
  65     return id;
  66   }
  67
  68   void PushBack(QuicStreamId stream_id, QuicPriority priority) {
  69     if (stream_id == kCryptoStreamId) {
  70       DCHECK_EQ(kHighestPriority, priority);
  71       // TODO(avd) Add DCHECK(!crypto_stream_blocked_)
  72       crypto_stream_blocked_ = true;
  73       return;
  74     }
  75
  76     if (stream_id == kHeadersStreamId) {
  77       DCHECK_EQ(kHighestPriority, priority);
  78       // TODO(avd) Add DCHECK(!headers_stream_blocked_);
  79       headers_stream_blocked_ = true;
  80       return;
  81     }
  82
  83     if (blocked_streams_.find(stream_id) != blocked_streams_.end()) {
  84       DVLOG(1) << "Stream " << stream_id << " already in write blocked list.";
  85       return;
  86     }
  87
  88     base_write_blocked_list_.PushBack(
  89         stream_id, static_cast<SpdyPriority>(priority));
  90     blocked_streams_.insert(stream_id);
  91     return;
  92   }
  93
  94   bool crypto_stream_blocked() const { return crypto_stream_blocked_; }
  95   bool headers_stream_blocked() const { return headers_stream_blocked_; }
  96
  97  private:
  98   QuicWriteBlockedListBase base_write_blocked_list_;
  99   bool crypto_stream_blocked_;
 100   bool headers_stream_blocked_;
 101
 102   // Keep track of write blocked streams in a set for faster membership checking
 103   // than iterating over the base_write_blocked_list_. The contents of this set
 104   // should mirror the contents of base_write_blocked_list_.
 105   std::set<QuicStreamId> blocked_streams_;
 106
 107   DISALLOW_COPY_AND_ASSIGN(QuicWriteBlockedList);
 108 };
 109
 110 }  // namespace net
 111
 112
 113 #endif  // NET_QUIC_QUIC_WRITE_BLOCKED_LIST_H_