| // 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_ENCODER_H_ |
| #define QUICHE_SPDY_CORE_HPACK_HPACK_ENCODER_H_ |
| |
| #include <stddef.h> |
| |
| #include <functional> |
| #include <map> |
| #include <memory> |
| #include <string> |
| #include <utility> |
| #include <vector> |
| |
| #include "absl/strings/string_view.h" |
| #include "common/platform/api/quiche_export.h" |
| #include "spdy/core/hpack/hpack_header_table.h" |
| #include "spdy/core/hpack/hpack_output_stream.h" |
| #include "spdy/core/spdy_protocol.h" |
| |
| // An HpackEncoder encodes header sets as outlined in |
| // http://tools.ietf.org/html/rfc7541. |
| |
| namespace spdy { |
| |
| namespace test { |
| class HpackEncoderPeer; |
| } // namespace test |
| |
| class QUICHE_EXPORT_PRIVATE HpackEncoder { |
| public: |
| using Representation = std::pair<absl::string_view, absl::string_view>; |
| using Representations = std::vector<Representation>; |
| |
| // Callers may provide a HeaderListener to be informed of header name-value |
| // pairs processed by this encoder. |
| using HeaderListener = |
| std::function<void(absl::string_view, absl::string_view)>; |
| |
| // An indexing policy should return true if the provided header name-value |
| // pair should be inserted into the HPACK dynamic table. |
| using IndexingPolicy = |
| std::function<bool(absl::string_view, absl::string_view)>; |
| |
| HpackEncoder(); |
| HpackEncoder(const HpackEncoder&) = delete; |
| HpackEncoder& operator=(const HpackEncoder&) = delete; |
| ~HpackEncoder(); |
| |
| // Encodes and returns the given header set as a string. |
| std::string EncodeHeaderBlock(const SpdyHeaderBlock& header_set); |
| |
| class QUICHE_EXPORT_PRIVATE ProgressiveEncoder { |
| public: |
| virtual ~ProgressiveEncoder() {} |
| |
| // Returns true iff more remains to encode. |
| virtual bool HasNext() const = 0; |
| |
| // Encodes and returns up to max_encoded_bytes of the current header block. |
| virtual std::string Next(size_t max_encoded_bytes) = 0; |
| }; |
| |
| // Returns a ProgressiveEncoder which must be outlived by both the given |
| // SpdyHeaderBlock and this object. |
| std::unique_ptr<ProgressiveEncoder> EncodeHeaderSet( |
| const SpdyHeaderBlock& header_set); |
| // Returns a ProgressiveEncoder which must be outlived by this HpackEncoder. |
| // The encoder will not attempt to split any \0-delimited values in |
| // |representations|. If such splitting is desired, it must be performed by |
| // the caller when constructing the list of representations. |
| std::unique_ptr<ProgressiveEncoder> EncodeRepresentations( |
| const Representations& representations); |
| |
| // Called upon a change to SETTINGS_HEADER_TABLE_SIZE. Specifically, this |
| // is to be called after receiving (and sending an acknowledgement for) a |
| // SETTINGS_HEADER_TABLE_SIZE update from the remote decoding endpoint. |
| void ApplyHeaderTableSizeSetting(size_t size_setting); |
| |
| // TODO(birenroy): Rename this GetDynamicTableCapacity(). |
| size_t CurrentHeaderTableSizeSetting() const { |
| return header_table_.settings_size_bound(); |
| } |
| |
| // This HpackEncoder will use |policy| to determine whether to insert header |
| // name-value pairs into the dynamic table. |
| void SetIndexingPolicy(IndexingPolicy policy) { should_index_ = policy; } |
| |
| // |listener| will be invoked for each header name-value pair processed by |
| // this encoder. |
| void SetHeaderListener(HeaderListener listener) { listener_ = listener; } |
| |
| void DisableCompression() { enable_compression_ = false; } |
| |
| // Returns the current dynamic table size, including the 32 bytes per entry |
| // overhead mentioned in RFC 7541 section 4.1. |
| size_t GetDynamicTableSize() const { return header_table_.size(); } |
| |
| private: |
| friend class test::HpackEncoderPeer; |
| |
| class RepresentationIterator; |
| class Encoderator; |
| |
| // Encodes a sequence of header name-value pairs as a single header block. |
| std::string EncodeRepresentations(RepresentationIterator* iter); |
| |
| // Emits a static/dynamic indexed representation (Section 7.1). |
| void EmitIndex(size_t index); |
| |
| // Emits a literal representation (Section 7.2). |
| void EmitIndexedLiteral(const Representation& representation); |
| void EmitNonIndexedLiteral(const Representation& representation, |
| bool enable_compression); |
| void EmitLiteral(const Representation& representation); |
| |
| // Emits a Huffman or identity string (whichever is smaller). |
| void EmitString(absl::string_view str); |
| |
| // Emits the current dynamic table size if the table size was recently |
| // updated and we have not yet emitted it (Section 6.3). |
| void MaybeEmitTableSize(); |
| |
| // Crumbles a cookie header into ";" delimited crumbs. |
| static void CookieToCrumbs(const Representation& cookie, |
| Representations* crumbs_out); |
| |
| // Crumbles other header field values at \0 delimiters. |
| static void DecomposeRepresentation(const Representation& header_field, |
| Representations* out); |
| |
| HpackHeaderTable header_table_; |
| HpackOutputStream output_stream_; |
| |
| size_t min_table_size_setting_received_; |
| HeaderListener listener_; |
| IndexingPolicy should_index_; |
| bool enable_compression_; |
| bool should_emit_table_size_; |
| }; |
| |
| } // namespace spdy |
| |
| #endif // QUICHE_SPDY_CORE_HPACK_HPACK_ENCODER_H_ |