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// 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 QUICHE_SPDY_CORE_HPACK_HPACK_ENTRY_H_
#define QUICHE_SPDY_CORE_HPACK_HPACK_ENTRY_H_
#include <cstddef>
#include <cstdint>
#include <string>
#include "absl/strings/string_view.h"
#include "common/platform/api/quiche_export.h"
// All section references below are to
// http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-08
namespace spdy {
// A structure for an entry in the static table (3.3.1)
// and the header table (3.3.2).
class QUICHE_EXPORT_PRIVATE HpackEntry {
public:
// The constant amount added to name().size() and value().size() to
// get the size of an HpackEntry as defined in 5.1.
static const size_t kSizeOverhead;
// 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).
//
// The combination of |is_static| and |insertion_index| allows an
// HpackEntryTable to determine the index of an HpackEntry in O(1) time.
// Copies |name| and |value|.
HpackEntry(absl::string_view name,
absl::string_view value,
bool is_static,
size_t insertion_index);
// Create a 'lookup' entry (only) suitable for querying a HpackEntrySet. The
// instance InsertionIndex() always returns 0 and IsLookup() returns true.
// The memory backing |name| and |value| must outlive this object.
HpackEntry(absl::string_view name, absl::string_view value);
HpackEntry(const HpackEntry& other);
HpackEntry& operator=(const HpackEntry& other);
// Creates an entry with empty name and value. Only defined so that
// entries can be stored in STL containers.
HpackEntry();
~HpackEntry();
absl::string_view name() const { return name_ref_; }
absl::string_view value() const { return value_ref_; }
// Returns whether this entry is a member of the static (as opposed to
// dynamic) table.
bool IsStatic() const { return type_ == STATIC; }
// Returns whether this entry is a lookup-only entry.
bool IsLookup() const { return type_ == LOOKUP; }
// 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 5.1.
static size_t Size(absl::string_view name, absl::string_view value);
size_t Size() const;
std::string GetDebugString() const;
int64_t time_added() const { return time_added_; }
void set_time_added(int64_t now) { time_added_ = now; }
// Returns the estimate of dynamically allocated memory in bytes.
size_t EstimateMemoryUsage() const;
private:
enum EntryType {
LOOKUP,
DYNAMIC,
STATIC,
};
// These members are not used for LOOKUP entries.
std::string name_;
std::string value_;
// These members are always valid. For DYNAMIC and STATIC entries, they
// always point to |name_| and |value_|.
absl::string_view name_ref_;
absl::string_view value_ref_;
// The entry's index in the total set of entries ever inserted into the header
// table.
size_t insertion_index_;
EntryType type_;
// For HpackHeaderTable::DebugVisitorInterface
int64_t time_added_;
};
} // namespace spdy
#endif // QUICHE_SPDY_CORE_HPACK_HPACK_ENTRY_H_