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| 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_SPDY_HPACK_HPACK_HEADER_TABLE_H_ | |
| 6 #define NET_SPDY_HPACK_HPACK_HEADER_TABLE_H_ | |
| 7 | |
| 8 #include <cstddef> | |
| 9 #include <deque> | |
| 10 #include <memory> | |
| 11 #include <unordered_map> | |
| 12 #include <unordered_set> | |
| 13 | |
| 14 #include "base/macros.h" | |
| 15 #include "net/base/net_export.h" | |
| 16 #include "net/spdy/hpack/hpack_entry.h" | |
| 17 #include "net/spdy/platform/api/spdy_string_piece.h" | |
| 18 | |
| 19 // All section references below are to http://tools.ietf.org/html/rfc7541. | |
| 20 | |
| 21 namespace net { | |
| 22 | |
| 23 namespace test { | |
| 24 class HpackHeaderTablePeer; | |
| 25 } // namespace test | |
| 26 | |
| 27 // A data structure for the static table (2.3.1) and the dynamic table (2.3.2). | |
| 28 class NET_EXPORT_PRIVATE HpackHeaderTable { | |
| 29 public: | |
| 30 friend class test::HpackHeaderTablePeer; | |
| 31 | |
| 32 // Debug visitor my be used to extract debug/internal information | |
| 33 // about the HpackHeaderTable as it operates. | |
| 34 // | |
| 35 // Most HpackHeaderTable implementations do not need to bother with | |
| 36 // this interface at all. | |
| 37 class DebugVisitorInterface { | |
| 38 public: | |
| 39 virtual ~DebugVisitorInterface() {} | |
| 40 | |
| 41 // |OnNewEntry()| and |OnUseEntry()| can be used together to | |
| 42 // gather data about the distribution of time intervals between | |
| 43 // creation and reference of entries in the dynamic table. The | |
| 44 // data is desired to sanity check a proposed extension to HPACK | |
| 45 // for QUIC that would eliminate inter-stream head of line | |
| 46 // blocking (due to standard HPACK). The visitor should return | |
| 47 // the current time from |OnNewEntry()|, which will be passed | |
| 48 // to |OnUseEntry()| each time that particular entry is used to | |
| 49 // emit an indexed representation. | |
| 50 virtual int64_t OnNewEntry(const HpackEntry& entry) = 0; | |
| 51 virtual void OnUseEntry(const HpackEntry& entry) = 0; | |
| 52 }; | |
| 53 | |
| 54 // HpackHeaderTable takes advantage of the deque property that references | |
| 55 // remain valid, so long as insertions & deletions are at the head & tail. | |
| 56 // If this changes (eg we start to drop entries from the middle of the table), | |
| 57 // this needs to be a std::list, in which case |*_index_| can be trivially | |
| 58 // extended to map to list iterators. | |
| 59 typedef std::deque<HpackEntry> EntryTable; | |
| 60 | |
| 61 struct NET_EXPORT_PRIVATE EntryHasher { | |
| 62 size_t operator()(const HpackEntry* entry) const; | |
| 63 }; | |
| 64 struct NET_EXPORT_PRIVATE EntriesEq { | |
| 65 bool operator()(const HpackEntry* lhs, const HpackEntry* rhs) const; | |
| 66 }; | |
| 67 | |
| 68 using UnorderedEntrySet = | |
| 69 std::unordered_set<HpackEntry*, EntryHasher, EntriesEq>; | |
| 70 using NameToEntryMap = std:: | |
| 71 unordered_map<SpdyStringPiece, const HpackEntry*, base::StringPieceHash>; | |
| 72 | |
| 73 HpackHeaderTable(); | |
| 74 | |
| 75 ~HpackHeaderTable(); | |
| 76 | |
| 77 // Last-acknowledged value of SETTINGS_HEADER_TABLE_SIZE. | |
| 78 size_t settings_size_bound() const { return settings_size_bound_; } | |
| 79 | |
| 80 // Current and maximum estimated byte size of the table, as described in | |
| 81 // 4.1. Notably, this is /not/ the number of entries in the table. | |
| 82 size_t size() const { return size_; } | |
| 83 size_t max_size() const { return max_size_; } | |
| 84 | |
| 85 // Returns the entry matching the index, or NULL. | |
| 86 const HpackEntry* GetByIndex(size_t index); | |
| 87 | |
| 88 // Returns the lowest-value entry having |name|, or NULL. | |
| 89 const HpackEntry* GetByName(SpdyStringPiece name); | |
| 90 | |
| 91 // Returns the lowest-index matching entry, or NULL. | |
| 92 const HpackEntry* GetByNameAndValue(SpdyStringPiece name, | |
| 93 SpdyStringPiece value); | |
| 94 | |
| 95 // Returns the index of an entry within this header table. | |
| 96 size_t IndexOf(const HpackEntry* entry) const; | |
| 97 | |
| 98 // Sets the maximum size of the header table, evicting entries if | |
| 99 // necessary as described in 5.2. | |
| 100 void SetMaxSize(size_t max_size); | |
| 101 | |
| 102 // Sets the SETTINGS_HEADER_TABLE_SIZE bound of the table. Will call | |
| 103 // SetMaxSize() as needed to preserve max_size() <= settings_size_bound(). | |
| 104 void SetSettingsHeaderTableSize(size_t settings_size); | |
| 105 | |
| 106 // Determine the set of entries which would be evicted by the insertion | |
| 107 // of |name| & |value| into the table, as per section 4.4. No eviction | |
| 108 // actually occurs. The set is returned via range [begin_out, end_out). | |
| 109 void EvictionSet(SpdyStringPiece name, | |
| 110 SpdyStringPiece value, | |
| 111 EntryTable::iterator* begin_out, | |
| 112 EntryTable::iterator* end_out); | |
| 113 | |
| 114 // Adds an entry for the representation, evicting entries as needed. |name| | |
| 115 // and |value| must not be owned by an entry which could be evicted. The | |
| 116 // added HpackEntry is returned, or NULL is returned if all entries were | |
| 117 // evicted and the empty table is of insufficent size for the representation. | |
| 118 const HpackEntry* TryAddEntry(SpdyStringPiece name, SpdyStringPiece value); | |
| 119 | |
| 120 void DebugLogTableState() const; | |
| 121 | |
| 122 void set_debug_visitor(std::unique_ptr<DebugVisitorInterface> visitor) { | |
| 123 debug_visitor_ = std::move(visitor); | |
| 124 } | |
| 125 | |
| 126 // Returns the estimate of dynamically allocated memory in bytes. | |
| 127 size_t EstimateMemoryUsage() const; | |
| 128 | |
| 129 private: | |
| 130 // Returns number of evictions required to enter |name| & |value|. | |
| 131 size_t EvictionCountForEntry(SpdyStringPiece name, | |
| 132 SpdyStringPiece value) const; | |
| 133 | |
| 134 // Returns number of evictions required to reclaim |reclaim_size| table size. | |
| 135 size_t EvictionCountToReclaim(size_t reclaim_size) const; | |
| 136 | |
| 137 // Evicts |count| oldest entries from the table. | |
| 138 void Evict(size_t count); | |
| 139 | |
| 140 // |static_entries_| and |static_index_| are owned by HpackStaticTable | |
| 141 // singleton. | |
| 142 const EntryTable& static_entries_; | |
| 143 EntryTable dynamic_entries_; | |
| 144 | |
| 145 // Tracks the unique HpackEntry for a given header name and value. | |
| 146 const UnorderedEntrySet& static_index_; | |
| 147 | |
| 148 // Tracks the first static entry for each name in the static table. | |
| 149 const NameToEntryMap& static_name_index_; | |
| 150 | |
| 151 // Tracks the most recently inserted HpackEntry for a given header name and | |
| 152 // value. | |
| 153 UnorderedEntrySet dynamic_index_; | |
| 154 | |
| 155 // Tracks the most recently inserted HpackEntry for a given header name. | |
| 156 NameToEntryMap dynamic_name_index_; | |
| 157 | |
| 158 // Last acknowledged value for SETTINGS_HEADER_TABLE_SIZE. | |
| 159 size_t settings_size_bound_; | |
| 160 | |
| 161 // Estimated current and maximum byte size of the table. | |
| 162 // |max_size_| <= |settings_size_bound_| | |
| 163 size_t size_; | |
| 164 size_t max_size_; | |
| 165 | |
| 166 // Total number of table insertions which have occurred. Referenced by | |
| 167 // IndexOf() for determination of an HpackEntry's table index. | |
| 168 size_t total_insertions_; | |
| 169 | |
| 170 std::unique_ptr<DebugVisitorInterface> debug_visitor_; | |
| 171 | |
| 172 DISALLOW_COPY_AND_ASSIGN(HpackHeaderTable); | |
| 173 }; | |
| 174 | |
| 175 } // namespace net | |
| 176 | |
| 177 #endif // NET_SPDY_HPACK_HPACK_HEADER_TABLE_H_ | |
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Chromium Code Reviews
Issue 2832973003:
Split net/spdy into core and chromium subdirectories. (Closed)
