| // Copyright 2016 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_HTTP2_HPACK_DECODER_HPACK_DECODER_TABLES_H_ |
| #define QUICHE_HTTP2_HPACK_DECODER_HPACK_DECODER_TABLES_H_ |
| |
| // Static and dynamic tables for the HPACK decoder. See: |
| // http://httpwg.org/specs/rfc7541.html#indexing.tables |
| |
| // Note that the Lookup methods return nullptr if the requested index was not |
| // found. This should be treated as a COMPRESSION error according to the HTTP/2 |
| // spec, which is a connection level protocol error (i.e. the connection must |
| // be terminated). See these sections in the two RFCs: |
| // http://httpwg.org/specs/rfc7541.html#indexed.header.representation |
| // http://httpwg.org/specs/rfc7541.html#index.address.space |
| // http://httpwg.org/specs/rfc7540.html#HeaderBlock |
| |
| #include <stddef.h> |
| |
| #include <cstdint> |
| #include <iosfwd> |
| #include <string> |
| #include <utility> |
| #include <vector> |
| |
| #include "quiche/http2/http2_constants.h" |
| #include "quiche/common/platform/api/quiche_export.h" |
| #include "quiche/common/quiche_circular_deque.h" |
| |
| namespace http2 { |
| namespace test { |
| class HpackDecoderTablesPeer; |
| } // namespace test |
| |
| struct QUICHE_EXPORT HpackStringPair { |
| HpackStringPair(std::string name, std::string value); |
| ~HpackStringPair(); |
| |
| // Returns the size of a header entry with this name and value, per the RFC: |
| // http://httpwg.org/specs/rfc7541.html#calculating.table.size |
| size_t size() const { return 32 + name.size() + value.size(); } |
| |
| std::string DebugString() const; |
| |
| const std::string name; |
| const std::string value; |
| }; |
| |
| QUICHE_EXPORT std::ostream& operator<<(std::ostream& os, |
| const HpackStringPair& p); |
| |
| // See http://httpwg.org/specs/rfc7541.html#static.table.definition for the |
| // contents, and http://httpwg.org/specs/rfc7541.html#index.address.space for |
| // info about accessing the static table. |
| class QUICHE_EXPORT HpackDecoderStaticTable { |
| public: |
| explicit HpackDecoderStaticTable(const std::vector<HpackStringPair>* table); |
| // Uses a global table shared by all threads. |
| HpackDecoderStaticTable(); |
| |
| // If index is valid, returns a pointer to the entry, otherwise returns |
| // nullptr. |
| const HpackStringPair* Lookup(size_t index) const; |
| |
| private: |
| friend class test::HpackDecoderTablesPeer; |
| const std::vector<HpackStringPair>* const table_; |
| }; |
| |
| // HpackDecoderDynamicTable implements HPACK compression feature "indexed |
| // headers"; previously sent headers may be referenced later by their index |
| // in the dynamic table. See these sections of the RFC: |
| // http://httpwg.org/specs/rfc7541.html#dynamic.table |
| // http://httpwg.org/specs/rfc7541.html#dynamic.table.management |
| class QUICHE_EXPORT HpackDecoderDynamicTable { |
| public: |
| HpackDecoderDynamicTable(); |
| ~HpackDecoderDynamicTable(); |
| |
| HpackDecoderDynamicTable(const HpackDecoderDynamicTable&) = delete; |
| HpackDecoderDynamicTable& operator=(const HpackDecoderDynamicTable&) = delete; |
| |
| // Sets a new size limit, received from the peer; performs evictions if |
| // necessary to ensure that the current size does not exceed the new limit. |
| // The caller needs to have validated that size_limit does not |
| // exceed the acknowledged value of SETTINGS_HEADER_TABLE_SIZE. |
| void DynamicTableSizeUpdate(size_t size_limit); |
| |
| // Insert entry if possible. |
| // If entry is too large to insert, then dynamic table will be empty. |
| void Insert(std::string name, std::string value); |
| |
| // If index is valid, returns a pointer to the entry, otherwise returns |
| // nullptr. |
| const HpackStringPair* Lookup(size_t index) const; |
| |
| size_t size_limit() const { return size_limit_; } |
| size_t current_size() const { return current_size_; } |
| |
| private: |
| friend class test::HpackDecoderTablesPeer; |
| |
| // Drop older entries to ensure the size is not greater than limit. |
| void EnsureSizeNoMoreThan(size_t limit); |
| |
| // Removes the oldest dynamic table entry. |
| void RemoveLastEntry(); |
| |
| quiche::QuicheCircularDeque<HpackStringPair> table_; |
| |
| // The last received DynamicTableSizeUpdate value, initialized to |
| // SETTINGS_HEADER_TABLE_SIZE. |
| size_t size_limit_ = Http2SettingsInfo::DefaultHeaderTableSize(); |
| |
| size_t current_size_ = 0; |
| |
| // insert_count_ and debug_listener_ are used by a QUIC experiment; remove |
| // when the experiment is done. |
| size_t insert_count_; |
| }; |
| |
| class QUICHE_EXPORT HpackDecoderTables { |
| public: |
| HpackDecoderTables(); |
| ~HpackDecoderTables(); |
| |
| HpackDecoderTables(const HpackDecoderTables&) = delete; |
| HpackDecoderTables& operator=(const HpackDecoderTables&) = delete; |
| |
| // Sets a new size limit, received from the peer; performs evictions if |
| // necessary to ensure that the current size does not exceed the new limit. |
| // The caller needs to have validated that size_limit does not |
| // exceed the acknowledged value of SETTINGS_HEADER_TABLE_SIZE. |
| void DynamicTableSizeUpdate(size_t size_limit) { |
| dynamic_table_.DynamicTableSizeUpdate(size_limit); |
| } |
| |
| // Insert entry if possible. |
| // If entry is too large to insert, then dynamic table will be empty. |
| void Insert(std::string name, std::string value) { |
| dynamic_table_.Insert(std::move(name), std::move(value)); |
| } |
| |
| // If index is valid, returns a pointer to the entry, otherwise returns |
| // nullptr. |
| const HpackStringPair* Lookup(size_t index) const; |
| |
| // The size limit that the peer (the HPACK encoder) has told the decoder it is |
| // currently operating with. Defaults to SETTINGS_HEADER_TABLE_SIZE, 4096. |
| size_t header_table_size_limit() const { return dynamic_table_.size_limit(); } |
| |
| // Sum of the sizes of the dynamic table entries. |
| size_t current_header_table_size() const { |
| return dynamic_table_.current_size(); |
| } |
| |
| private: |
| friend class test::HpackDecoderTablesPeer; |
| HpackDecoderStaticTable static_table_; |
| HpackDecoderDynamicTable dynamic_table_; |
| }; |
| |
| } // namespace http2 |
| |
| #endif // QUICHE_HTTP2_HPACK_DECODER_HPACK_DECODER_TABLES_H_ |