Land recent SPDY changes (through 67282679)

net/spdy/hpack_entry.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_SPDY_HPACK_ENTRY_H_
 #define NET_SPDY_HPACK_ENTRY_H_
 
 #include <cstddef>
 #include <set>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/macros.h"
 #include "base/strings/string_piece.h"
 #include "net/base/net_export.h"
 
 // All section references below are to
 // http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-07
 
 namespace net {
 
 // A structure for an entry in the header table (3.1.2) and the
 // 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 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|).
   //
-  // 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.
+  // The combination of |is_static| and |insertion_index| allows an
+  // HpackEntryTable to determine the index of an HpackEntry 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);
+             size_t insertion_index);
 
   // 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.
+  // instance InsertionIndex() always returns 0 and IsLookup() returns true.
   HpackEntry(base::StringPiece name, base::StringPiece value);
 
-  // Creates an entry with empty name a value. Only defined so that
+  // Creates an entry with empty name and value. Only defined so that
   // entries can be stored in STL containers.
   HpackEntry();
 
   ~HpackEntry();
 
   const std::string& name() const { return name_; }
   const std::string& value() const { return value_; }
 
   // Returns whether this entry is a member of the static (as opposed to
   // dynamic) table.
-  bool IsStatic() const { return is_static_; }
+  bool IsStatic() const { return type_ == STATIC; }
+
+  // Returns whether this entry is a lookup-only entry.
+  bool IsLookup() const { return type_ == LOOKUP; }
 
   // 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 the entry's current index in the header table.
-  size_t Index() const;
+  // Used to compute the entry's index in the header table.
+  size_t InsertionIndex() const { return insertion_index_; }
 
   // 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;
 
  private:
+  enum EntryType {
+    LOOKUP,
+    DYNAMIC,
+    STATIC,
+  };
+
   // TODO(jgraettinger): Reduce copies, possibly via SpdyPinnableBufferPiece.
   std::string name_;
   std::string value_;
 
-  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_;
+  uint8 state_;
+  EntryType type_;
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_HPACK_ENTRY_H_