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1 // Copyright 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_WRITE_BLOCKED_LIST_H_ | |
6 #define NET_SPDY_WRITE_BLOCKED_LIST_H_ | |
7 | |
8 #include <algorithm> | |
9 #include <deque> | |
10 | |
11 #include "base/logging.h" | |
12 #include "net/spdy/spdy_protocol.h" | |
13 | |
14 namespace { | |
15 class WriteBlockedListPeer; | |
16 } | |
17 | |
18 namespace net { | |
19 | |
20 const int kHighestPriority = 0; | |
21 const int kLowestPriority = 7; | |
22 | |
23 template <typename IdType> | |
24 class WriteBlockedList { | |
25 public: | |
26 // 0(1) size lookup. 0(1) insert at front or back. | |
27 typedef std::deque<IdType> BlockedList; | |
28 typedef typename BlockedList::iterator iterator; | |
29 | |
30 static SpdyPriority ClampPriority(SpdyPriority priority) { | |
31 if (priority < kHighestPriority) { | |
32 LOG(DFATAL) << "Invalid priority: " << static_cast<int>(priority); | |
33 return kHighestPriority; | |
34 } | |
35 if (priority > kLowestPriority) { | |
36 LOG(DFATAL) << "Invalid priority: " << static_cast<int>(priority); | |
37 return kLowestPriority; | |
38 } | |
39 return priority; | |
40 } | |
41 | |
42 // Returns the priority of the highest priority list with sessions on it. | |
43 SpdyPriority GetHighestPriorityWriteBlockedList() const { | |
44 for (SpdyPriority i = 0; i <= kLowestPriority; ++i) { | |
45 if (write_blocked_lists_[i].size() > 0) | |
46 return i; | |
47 } | |
48 LOG(DFATAL) << "No blocked streams"; | |
49 return kHighestPriority; | |
50 } | |
51 | |
52 IdType PopFront(SpdyPriority priority) { | |
53 priority = ClampPriority(priority); | |
54 DCHECK(!write_blocked_lists_[priority].empty()); | |
55 IdType stream_id = write_blocked_lists_[priority].front(); | |
56 write_blocked_lists_[priority].pop_front(); | |
57 return stream_id; | |
58 } | |
59 | |
60 bool HasWriteBlockedStreamsGreaterThanPriority(SpdyPriority priority) const { | |
61 priority = ClampPriority(priority); | |
62 for (SpdyPriority i = kHighestPriority; i < priority; ++i) { | |
63 if (!write_blocked_lists_[i].empty()) { | |
64 return true; | |
65 } | |
66 } | |
67 return false; | |
68 } | |
69 | |
70 bool HasWriteBlockedStreams() const { | |
71 for (SpdyPriority i = kHighestPriority; i <= kLowestPriority; ++i) { | |
72 if (!write_blocked_lists_[i].empty()) { | |
73 return true; | |
74 } | |
75 } | |
76 return false; | |
77 } | |
78 | |
79 void PushBack(IdType stream_id, SpdyPriority priority) { | |
80 write_blocked_lists_[ClampPriority(priority)].push_back(stream_id); | |
81 } | |
82 | |
83 bool RemoveStreamFromWriteBlockedList(IdType stream_id, | |
84 SpdyPriority priority) { | |
85 // We shouldn't really add a stream_id to a list multiple times, | |
86 // but under some conditions it does happen. Doing a check in PushBack | |
87 // would be too costly, so instead we check here to eliminate duplicates. | |
88 bool found = false; | |
89 iterator it = std::find(write_blocked_lists_[priority].begin(), | |
90 write_blocked_lists_[priority].end(), | |
91 stream_id); | |
92 while (it != write_blocked_lists_[priority].end()) { | |
93 found = true; | |
94 iterator next_it = write_blocked_lists_[priority].erase(it); | |
95 it = std::find(next_it, write_blocked_lists_[priority].end(), stream_id); | |
96 } | |
97 return found; | |
98 } | |
99 | |
100 void UpdateStreamPriorityInWriteBlockedList(IdType stream_id, | |
101 SpdyPriority old_priority, | |
102 SpdyPriority new_priority) { | |
103 if (old_priority == new_priority) { | |
104 return; | |
105 } | |
106 bool found = RemoveStreamFromWriteBlockedList(stream_id, old_priority); | |
107 if (found) { | |
108 PushBack(stream_id, new_priority); | |
109 } | |
110 } | |
111 | |
112 size_t NumBlockedStreams() const { | |
113 size_t num_blocked_streams = 0; | |
114 for (SpdyPriority i = kHighestPriority; i <= kLowestPriority; ++i) { | |
115 num_blocked_streams += write_blocked_lists_[i].size(); | |
116 } | |
117 return num_blocked_streams; | |
118 } | |
119 | |
120 private: | |
121 friend WriteBlockedListPeer; | |
122 BlockedList write_blocked_lists_[kLowestPriority + 1]; | |
123 }; | |
124 | |
125 } // namespace net | |
126 | |
127 #endif // NET_SPDY_WRITE_BLOCKED_LIST_H_ | |
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