#define NET_SPDY_HPACK_ENTRY_H_
#include <cstddef>
-#include <deque>
+#include <set>
#include <string>
-#include <vector>
#include "base/basictypes.h"
#include "base/macros.h"
#include "base/strings/string_piece.h"
#include "net/base/net_export.h"
-namespace net {
-
// All section references below are to
// http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-06
+namespace net {
+
// A structure for an entry in the header table (3.1.2) and the
-// reference set (3.1.3). This structure also keeps track of how many
-// times the entry has been 'touched', which is useful for both
-// encoding and decoding.
+// reference set (3.1.3).
class NET_EXPORT_PRIVATE HpackEntry {
public:
// The constant amount added to name().size() and value().size() to
// get the size of an HpackEntry as defined in 3.3.1.
- static const uint32 kSizeOverhead;
-
- // The constant returned by touch_count() if an entry hasn't been
- // touched (which is distinct from an entry having a touch count of
- // 0).
+ static const size_t kSizeOverhead;
+
+ // Implements a total ordering of HpackEntry on name(), value(), then Index()
+ // ascending. Note that Index() may change over the lifetime of an HpackEntry,
+ // but the relative Index() order of two entries will not. This comparator is
+ // composed with the 'lookup' HpackEntry constructor to allow for efficient
+ // lower-bounding of matching entries.
+ struct NET_EXPORT_PRIVATE Comparator {
+ bool operator() (const HpackEntry* lhs, const HpackEntry* rhs) const;
+ };
+ typedef std::set<HpackEntry*, Comparator> OrderedSet;
+
+ // Creates an entry. Preconditions:
+ // - |is_static| captures whether this entry is a member of the static
+ // or dynamic header table.
+ // - |insertion_index| is this entry's index in the total set of entries ever
+ // inserted into the header table (including static entries).
+ // - |total_table_insertions_or_current_size| references an externally-
+ // updated count of either the total number of header insertions (if
+ // !|is_static|), or the current size of the header table (if |is_static|).
//
- // TODO(akalin): The distinction between untouched and having a
- // touch count of 0 is confusing. Think of a better way to represent
- // this state.
- static const uint32 kUntouched;
+ // The combination of |is_static|, |insertion_index|, and
+ // |total_table_insertions_or_current_size| allows an HpackEntry to determine
+ // its current table index in O(1) time.
+ HpackEntry(base::StringPiece name,
+ base::StringPiece value,
+ bool is_static,
+ size_t insertion_index,
+ const size_t* total_table_insertions_or_current_size);
+
+ // Create a 'lookup' entry (only) suitable for querying a HpackEntrySet. The
+ // instance Index() always returns 0, and will lower-bound all entries
+ // matching |name| & |value| in an OrderedSet.
+ HpackEntry(base::StringPiece name, base::StringPiece value);
// Creates an entry with empty name a value. Only defined so that
// entries can be stored in STL containers.
HpackEntry();
- // Creates an entry with a copy is made of the given name and value.
- //
- // TODO(akalin): Add option to not make a copy (for static table
- // entries).
- HpackEntry(base::StringPiece name, base::StringPiece value);
+ ~HpackEntry();
- // Copy constructor and assignment operator welcome.
+ const std::string& name() const { return name_; }
+ const std::string& value() const { return value_; }
- // The name() and value() StringPieces have the same lifetime as
- // this entry.
+ // Returns whether this entry is a member of the static (as opposed to
+ // dynamic) table.
+ bool IsStatic() const { return is_static_; }
- base::StringPiece name() const { return base::StringPiece(name_); }
- base::StringPiece value() const { return base::StringPiece(value_); }
+ // Returns and sets the state of the entry, or zero if never set.
+ // The semantics of |state| are specific to the encoder or decoder.
+ uint8 state() const { return state_; }
+ void set_state(uint8 state) { state_ = state; }
- // Returns whether or not this entry is in the reference set.
- bool IsReferenced() const;
+ // Returns the entry's current index in the header table.
+ size_t Index() const;
- // Returns how many touches this entry has, or kUntouched if this
- // entry hasn't been touched at all. The meaning of the touch count
- // is defined by whatever is calling
- // AddTouchCount()/ClearTouchCount() (i.e., the encoder or decoder).
- uint32 TouchCount() const;
-
- // Returns the size of an entry as defined in 3.3.1. The returned
- // value may not necessarily fit in 32 bits.
+ // Returns the size of an entry as defined in 3.3.1.
+ static size_t Size(base::StringPiece name, base::StringPiece value);
size_t Size() const;
std::string GetDebugString() const;
- // Returns whether this entry has the same name, value, referenced
- // state, and touch count as the given one.
- bool Equals(const HpackEntry& other) const;
-
- void SetReferenced(bool referenced);
-
- // Adds the given number of touches to this entry (see
- // TouchCount()). The total number of touches must not exceed 2^31 -
- // 2. It is guaranteed that this entry's touch count will not equal
- // kUntouched after this function is called (even if touch_count ==
- // 0).
- void AddTouches(uint32 additional_touch_count);
-
- // Sets the touch count of this entry to kUntouched.
- void ClearTouches();
-
private:
+ // TODO(jgraettinger): Reduce copies, possibly via SpdyPinnableBufferPiece.
std::string name_;
std::string value_;
- // The high bit stores 'referenced' and the rest stores the touch
- // count.
- uint32 referenced_and_touch_count_;
+ bool is_static_;
+ uint8 state_;
+
+ // The entry's index in the total set of entries ever inserted into the header
+ // table.
+ size_t insertion_index_;
+
+ // If |is_static_|, references the current size of the headers table.
+ // Else, references the total number of header insertions which have occurred.
+ const size_t* total_insertions_or_size_;
};
} // namespace net
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