| // Copyright (c) 2018 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_QUIC_CORE_QPACK_QPACK_DECODER_H_ |
| #define QUICHE_QUIC_CORE_QPACK_QPACK_DECODER_H_ |
| |
| #include <cstdint> |
| #include <memory> |
| #include <set> |
| |
| #include "absl/strings/string_view.h" |
| #include "quiche/quic/core/qpack/qpack_decoder_stream_sender.h" |
| #include "quiche/quic/core/qpack/qpack_encoder_stream_receiver.h" |
| #include "quiche/quic/core/qpack/qpack_header_table.h" |
| #include "quiche/quic/core/qpack/qpack_progressive_decoder.h" |
| #include "quiche/quic/core/quic_error_codes.h" |
| #include "quiche/quic/core/quic_types.h" |
| #include "quiche/quic/platform/api/quic_export.h" |
| |
| namespace quic { |
| |
| // QPACK decoder class. Exactly one instance should exist per QUIC connection. |
| // This class vends a new QpackProgressiveDecoder instance for each new header |
| // list to be encoded. |
| // QpackProgressiveDecoder detects and signals errors with header blocks, which |
| // are stream errors. |
| // The only input of QpackDecoder is the encoder stream. Any error QpackDecoder |
| // signals is an encoder stream error, which is fatal to the connection. |
| class QUIC_EXPORT_PRIVATE QpackDecoder |
| : public QpackEncoderStreamReceiver::Delegate, |
| public QpackProgressiveDecoder::BlockedStreamLimitEnforcer, |
| public QpackProgressiveDecoder::DecodingCompletedVisitor { |
| public: |
| // Interface for receiving notification that an error has occurred on the |
| // encoder stream. This MUST be treated as a connection error of type |
| // HTTP_QPACK_ENCODER_STREAM_ERROR. |
| class QUIC_EXPORT_PRIVATE EncoderStreamErrorDelegate { |
| public: |
| virtual ~EncoderStreamErrorDelegate() {} |
| |
| virtual void OnEncoderStreamError(QuicErrorCode error_code, |
| absl::string_view error_message) = 0; |
| }; |
| |
| QpackDecoder(uint64_t maximum_dynamic_table_capacity, |
| uint64_t maximum_blocked_streams, |
| EncoderStreamErrorDelegate* encoder_stream_error_delegate); |
| ~QpackDecoder() override; |
| |
| // Signal to the peer's encoder that a stream is reset. This lets the peer's |
| // encoder know that no more header blocks will be processed on this stream, |
| // therefore references to dynamic table entries shall not prevent their |
| // eviction. |
| // This method should be called regardless of whether a header block is being |
| // decoded on that stream, because a header block might be in flight from the |
| // peer. |
| // This method should be called every time a request or push stream is reset |
| // for any reason: for example, client cancels request, or a decoding error |
| // occurs and HeadersHandlerInterface::OnDecodingErrorDetected() is called. |
| // This method should also be called if the stream is reset by the peer, |
| // because the peer's encoder can only evict entries referenced by header |
| // blocks once it receives acknowledgement from this endpoint that the stream |
| // is reset. |
| // However, this method should not be called if the stream is closed normally |
| // using the FIN bit. |
| void OnStreamReset(QuicStreamId stream_id); |
| |
| // QpackProgressiveDecoder::BlockedStreamLimitEnforcer implementation. |
| bool OnStreamBlocked(QuicStreamId stream_id) override; |
| void OnStreamUnblocked(QuicStreamId stream_id) override; |
| |
| // QpackProgressiveDecoder::DecodingCompletedVisitor implementation. |
| void OnDecodingCompleted(QuicStreamId stream_id, |
| uint64_t required_insert_count) override; |
| |
| // Factory method to create a QpackProgressiveDecoder for decoding a header |
| // block. |handler| must remain valid until the returned |
| // QpackProgressiveDecoder instance is destroyed or the decoder calls |
| // |handler->OnHeaderBlockEnd()|. |
| std::unique_ptr<QpackProgressiveDecoder> CreateProgressiveDecoder( |
| QuicStreamId stream_id, |
| QpackProgressiveDecoder::HeadersHandlerInterface* handler); |
| |
| // QpackEncoderStreamReceiver::Delegate implementation |
| void OnInsertWithNameReference(bool is_static, uint64_t name_index, |
| absl::string_view value) override; |
| void OnInsertWithoutNameReference(absl::string_view name, |
| absl::string_view value) override; |
| void OnDuplicate(uint64_t index) override; |
| void OnSetDynamicTableCapacity(uint64_t capacity) override; |
| void OnErrorDetected(QuicErrorCode error_code, |
| absl::string_view error_message) override; |
| |
| // delegate must be set if dynamic table capacity is not zero. |
| void set_qpack_stream_sender_delegate(QpackStreamSenderDelegate* delegate) { |
| decoder_stream_sender_.set_qpack_stream_sender_delegate(delegate); |
| } |
| |
| QpackStreamReceiver* encoder_stream_receiver() { |
| return &encoder_stream_receiver_; |
| } |
| |
| // True if any dynamic table entries have been referenced from a header block. |
| bool dynamic_table_entry_referenced() const { |
| return header_table_.dynamic_table_entry_referenced(); |
| } |
| |
| private: |
| EncoderStreamErrorDelegate* const encoder_stream_error_delegate_; |
| QpackEncoderStreamReceiver encoder_stream_receiver_; |
| QpackDecoderStreamSender decoder_stream_sender_; |
| QpackDecoderHeaderTable header_table_; |
| std::set<QuicStreamId> blocked_streams_; |
| const uint64_t maximum_blocked_streams_; |
| |
| // Known Received Count is the number of insertions the encoder has received |
| // acknowledgement for (through Header Acknowledgement and Insert Count |
| // Increment instructions). The encoder must keep track of it in order to be |
| // able to send Insert Count Increment instructions. See |
| // https://quicwg.org/base-drafts/draft-ietf-quic-qpack.html#known-received-count. |
| uint64_t known_received_count_; |
| }; |
| |
| // QpackDecoder::EncoderStreamErrorDelegate implementation that does nothing. |
| class QUIC_EXPORT_PRIVATE NoopEncoderStreamErrorDelegate |
| : public QpackDecoder::EncoderStreamErrorDelegate { |
| public: |
| ~NoopEncoderStreamErrorDelegate() override = default; |
| |
| void OnEncoderStreamError(QuicErrorCode /*error_code*/, |
| absl::string_view /*error_message*/) override {} |
| }; |
| |
| } // namespace quic |
| |
| #endif // QUICHE_QUIC_CORE_QPACK_QPACK_DECODER_H_ |