#include <cstddef>
#include <deque>
-#include <vector>
+#include <set>
#include "base/basictypes.h"
#include "base/macros.h"
#include "net/base/net_export.h"
#include "net/spdy/hpack_entry.h"
-namespace net {
-
// All section references below are to
// http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-06
+namespace net {
+
+namespace test {
+class HpackHeaderTablePeer;
+} // namespace test
+
// A data structure for both the header table (described in 3.1.2) and
-// the reference set (3.1.3). This structure also keeps track of how
-// many times a header has been 'touched', which is useful for both
-// encoding and decoding.
+// the reference set (3.1.3).
class NET_EXPORT_PRIVATE HpackHeaderTable {
public:
+ friend class test::HpackHeaderTablePeer;
+
+ // HpackHeaderTable takes advantage of the deque property that references
+ // remain valid, so long as insertions & deletions are at the head & tail.
+ // If this changes (eg we start to drop entries from the middle of the table),
+ // this needs to be a std::list, in which case |index_| can be trivially
+ // extended to map to list iterators.
+ typedef std::deque<HpackEntry> EntryTable;
+
HpackHeaderTable();
~HpackHeaderTable();
- uint32 size() const { return size_; }
- uint32 max_size() const { return max_size_; }
+ // Last-aknowledged value of SETTINGS_HEADER_TABLE_SIZE.
+ size_t settings_size_bound() { return settings_size_bound_; }
+
+ // Current and maximum estimated byte size of the table, as described in
+ // 3.3.1. Notably, this is /not/ the number of entries in the table.
+ size_t size() const { return size_; }
+ size_t max_size() const { return max_size_; }
+
+ const HpackEntry::OrderedSet& reference_set() {
+ return reference_set_;
+ }
- // Returns the total number of entries.
- uint32 GetEntryCount() const;
+ // Returns the entry matching the index, or NULL.
+ HpackEntry* GetByIndex(size_t index);
- // The given index must be >= 1 and <= GetEntryCount().
- const HpackEntry& GetEntry(uint32 index) const;
+ // Returns the lowest-value entry having |name|, or NULL.
+ HpackEntry* GetByName(base::StringPiece name);
- // The given index must be >= 1 and <= GetEntryCount().
- HpackEntry* GetMutableEntry(uint32 index);
+ // Returns the lowest-index matching entry, or NULL.
+ HpackEntry* GetByNameAndValue(base::StringPiece name,
+ base::StringPiece value);
// Sets the maximum size of the header table, evicting entries if
// necessary as described in 3.3.2.
- void SetMaxSize(uint32 max_size);
-
- // The given entry must not be one from the header table, since it
- // may get evicted. Tries to add the given entry to the header
- // table, evicting entries if necessary as described in 3.3.3. index
- // will be filled in with the index of the added entry, or 0 if the
- // entry could not be added. removed_referenced_indices will be
- // filled in with the indices of any removed entries that were in
- // the reference set.
- void TryAddEntry(const HpackEntry& entry,
- uint32* index,
- std::vector<uint32>* removed_referenced_indices);
+ void SetMaxSize(size_t max_size);
+
+ // Sets the SETTINGS_HEADER_TABLE_SIZE bound of the table. Will call
+ // SetMaxSize() as needed to preserve max_size() <= settings_size_bound().
+ void SetSettingsHeaderTableSize(size_t settings_size);
+
+ // Determine the set of entries which would be evicted by the insertion
+ // of |name| & |value| into the table, as per section 3.3.3. No eviction
+ // actually occurs. The set is returned via range [begin_out, end_out).
+ void EvictionSet(base::StringPiece name, base::StringPiece value,
+ EntryTable::iterator* begin_out,
+ EntryTable::iterator* end_out);
+
+ // Adds an entry for the representation, evicting entries as needed. |name|
+ // and |value| must not be owned by an entry which could be evicted. The
+ // added HpackEntry is returned, or NULL is returned if all entries were
+ // evicted and the empty table is of insufficent size for the representation.
+ HpackEntry* TryAddEntry(base::StringPiece name, base::StringPiece value);
+
+ // Toggles the presence of a dynamic entry in the reference set. Returns
+ // true if the entry was added, or false if removed. It is an error to
+ // Toggle(entry) if |entry->state()| != 0.
+ bool Toggle(HpackEntry* entry);
+
+ // Removes all entries from the reference set. Sets the state of each removed
+ // entry to zero.
+ void ClearReferenceSet();
+
+ void DebugLogTableState() const;
private:
- std::deque<HpackEntry> entries_;
- uint32 size_;
- uint32 max_size_;
+ // Returns number of evictions required to enter |name| & |value|.
+ size_t EvictionCountForEntry(base::StringPiece name,
+ base::StringPiece value) const;
+
+ // Returns number of evictions required to reclaim |reclaim_size| table size.
+ size_t EvictionCountToReclaim(size_t reclaim_size) const;
+
+ // Evicts |count| oldest entries from the table.
+ void Evict(size_t count);
+
+ EntryTable dynamic_entries_;
+ EntryTable static_entries_;
+
+ // Full table index, over |dynamic_entries_| and |static_entries_|.
+ HpackEntry::OrderedSet index_;
+ // The reference set is strictly a subset of |dynamic_entries_|.
+ HpackEntry::OrderedSet reference_set_;
+
+ // Last acknowledged value for SETTINGS_HEADER_TABLE_SIZE.
+ size_t settings_size_bound_;
+
+ // Estimated current and maximum byte size of the table.
+ // |max_size_| <= |settings_header_table_size_|
+ size_t size_;
+ size_t max_size_;
+
+ // Total number of table insertions which have occurred. Referenced by
+ // dynamic HpackEntry instances for determination of table index.
+ size_t total_insertions_;
+
+ // Current number of dynamic entries. Referenced by static HpackEntry
+ // instances for determination of table index.
+ size_t dynamic_entries_count_;
DISALLOW_COPY_AND_ASSIGN(HpackHeaderTable);
};
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