blob: 0c263584f66680ca2aa7af3ae7dbf5d3038596c5 [file] [log] [blame]
// 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 <utility>
#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 {
// The constant amount added to name().size() and value().size() to
// get the size of an HpackEntry as defined in 5.1.
constexpr size_t kHpackEntrySizeOverhead = 32;
// A structure for looking up entries in the static and dynamic tables.
struct QUICHE_EXPORT_PRIVATE HpackLookupEntry {
absl::string_view name;
absl::string_view value;
bool operator==(const HpackLookupEntry& other) const {
return name == other.name && value == other.value;
}
// Abseil hashing framework extension according to absl/hash/hash.h:
template <typename H>
friend H AbslHashValue(H h, const HpackLookupEntry& entry) {
return H::combine(std::move(h), entry.name, entry.value);
}
};
// 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:
HpackEntry(std::string name, std::string value);
// Make HpackEntry non-copyable to make sure it is always moved.
HpackEntry(const HpackEntry&) = delete;
HpackEntry& operator=(const HpackEntry&) = delete;
HpackEntry(HpackEntry&&) = default;
HpackEntry& operator=(HpackEntry&&) = default;
// Getters for std::string members traditionally return const std::string&.
// However, HpackHeaderTable uses string_view as keys in the maps
// static_name_index_ and dynamic_name_index_. If HpackEntry::name() returned
// const std::string&, then
// dynamic_name_index_.insert(std::make_pair(entry.name(), index));
// would silently create a dangling reference: make_pair infers type from the
// return type of entry.name() and silently creates a temporary string copy.
// Insert creates a string_view that points to this copy, which then
// immediately goes out of scope and gets destroyed. While this is quite easy
// to avoid, for example, by explicitly specifying type as a template
// parameter to make_pair, returning string_view here is less error-prone.
absl::string_view name() const { return name_; }
absl::string_view value() const { return value_; }
// 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;
// Returns the estimate of dynamically allocated memory in bytes.
size_t EstimateMemoryUsage() const;
private:
std::string name_;
std::string value_;
};
} // namespace spdy
#endif // QUICHE_SPDY_CORE_HPACK_HPACK_ENTRY_H_