Project import generated by Copybara.
PiperOrigin-RevId: 237361882
Change-Id: I109a68f44db867b20f8c6a7732b0ce657133e52a
diff --git a/quic/core/qpack/qpack_progressive_decoder.h b/quic/core/qpack/qpack_progressive_decoder.h
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+// 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_PROGRESSIVE_DECODER_H_
+#define QUICHE_QUIC_CORE_QPACK_QPACK_PROGRESSIVE_DECODER_H_
+
+#include <cstdint>
+#include <memory>
+
+#include "net/third_party/quiche/src/quic/core/qpack/qpack_decoder_stream_sender.h"
+#include "net/third_party/quiche/src/quic/core/qpack/qpack_encoder_stream_receiver.h"
+#include "net/third_party/quiche/src/quic/core/qpack/qpack_instruction_decoder.h"
+#include "net/third_party/quiche/src/quic/core/quic_types.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_export.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_string.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_string_piece.h"
+
+namespace quic {
+
+class QpackHeaderTable;
+
+// Class to decode a single header block.
+class QUIC_EXPORT_PRIVATE QpackProgressiveDecoder
+ : public QpackInstructionDecoder::Delegate {
+ public:
+ // Interface for receiving decoded header block from the decoder.
+ class QUIC_EXPORT_PRIVATE HeadersHandlerInterface {
+ public:
+ virtual ~HeadersHandlerInterface() {}
+
+ // Called when a new header name-value pair is decoded. Multiple values for
+ // a given name will be emitted as multiple calls to OnHeader.
+ virtual void OnHeaderDecoded(QuicStringPiece name,
+ QuicStringPiece value) = 0;
+
+ // Called when the header block is completely decoded.
+ // Indicates the total number of bytes in this block.
+ // The decoder will not access the handler after this call.
+ // Note that this method might not be called synchronously when the header
+ // block is received on the wire, in case decoding is blocked on receiving
+ // entries on the encoder stream. TODO(bnc): Implement blocked decoding.
+ virtual void OnDecodingCompleted() = 0;
+
+ // Called when a decoding error has occurred. No other methods will be
+ // called afterwards.
+ virtual void OnDecodingErrorDetected(QuicStringPiece error_message) = 0;
+ };
+
+ QpackProgressiveDecoder() = delete;
+ QpackProgressiveDecoder(QuicStreamId stream_id,
+ QpackHeaderTable* header_table,
+ QpackDecoderStreamSender* decoder_stream_sender,
+ HeadersHandlerInterface* handler);
+ QpackProgressiveDecoder(const QpackProgressiveDecoder&) = delete;
+ QpackProgressiveDecoder& operator=(const QpackProgressiveDecoder&) = delete;
+ ~QpackProgressiveDecoder() override = default;
+
+ // Calculate Required Insert Count from Encoded Required Insert Count,
+ // MaxEntries, and total number of dynamic table insertions according to
+ // https://quicwg.org/base-drafts/draft-ietf-quic-qpack.html#ric.
+ // Returns true on success, false on invalid input or overflow/underflow.
+ static bool DecodeRequiredInsertCount(uint64_t encoded_required_insert_count,
+ uint64_t max_entries,
+ uint64_t total_number_of_inserts,
+ uint64_t* required_insert_count);
+
+ // Provide a data fragment to decode.
+ void Decode(QuicStringPiece data);
+
+ // Signal that the entire header block has been received and passed in
+ // through Decode(). No methods must be called afterwards.
+ void EndHeaderBlock();
+
+ // QpackInstructionDecoder::Delegate implementation.
+ bool OnInstructionDecoded(const QpackInstruction* instruction) override;
+ void OnError(QuicStringPiece error_message) override;
+
+ private:
+ bool DoIndexedHeaderFieldInstruction();
+ bool DoIndexedHeaderFieldPostBaseInstruction();
+ bool DoLiteralHeaderFieldNameReferenceInstruction();
+ bool DoLiteralHeaderFieldPostBaseInstruction();
+ bool DoLiteralHeaderFieldInstruction();
+ bool DoPrefixInstruction();
+
+ // Calculates Base from |required_insert_count_|, which must be set before
+ // calling this method, and sign bit and Delta Base in the Header Data Prefix,
+ // which are passed in as arguments. Returns true on success, false on
+ // failure due to overflow/underflow.
+ bool DeltaBaseToBase(bool sign, uint64_t delta_base, uint64_t* base);
+
+ // The request stream can use relative index (but different from the kind of
+ // relative index used on the encoder stream), and post-base index.
+ // These methods convert relative index and post-base index to absolute index
+ // (one based). They return true on success, or false if conversion fails due
+ // to overflow/underflow. On success, |*absolute_index| is guaranteed to be
+ // strictly less than std::numeric_limits<uint64_t>::max().
+ bool RequestStreamRelativeIndexToAbsoluteIndex(
+ uint64_t relative_index,
+ uint64_t* absolute_index) const;
+ bool PostBaseIndexToAbsoluteIndex(uint64_t post_base_index,
+ uint64_t* absolute_index) const;
+
+ const QuicStreamId stream_id_;
+
+ // |prefix_decoder_| only decodes a handful of bytes then it can be
+ // destroyed to conserve memory. |instruction_decoder_|, on the other hand,
+ // is used until the entire header block is decoded.
+ std::unique_ptr<QpackInstructionDecoder> prefix_decoder_;
+ QpackInstructionDecoder instruction_decoder_;
+
+ const QpackHeaderTable* const header_table_;
+ QpackDecoderStreamSender* const decoder_stream_sender_;
+ HeadersHandlerInterface* const handler_;
+
+ // Required Insert Count and Base are decoded from the Header Data Prefix.
+ uint64_t required_insert_count_;
+ uint64_t base_;
+
+ // Required Insert Count is one larger than the largest absolute index of all
+ // referenced dynamic table entries, or zero if no dynamic table entries are
+ // referenced. |required_insert_count_so_far_| starts out as zero and keeps
+ // track of the Required Insert Count based on entries decoded so far.
+ // After decoding is completed, it is compared to |required_insert_count_|.
+ uint64_t required_insert_count_so_far_;
+
+ // False until prefix is fully read and decoded.
+ bool prefix_decoded_;
+
+ // True until EndHeaderBlock() is called.
+ bool decoding_;
+
+ // True if a decoding error has been detected.
+ bool error_detected_;
+};
+
+} // namespace quic
+
+#endif // QUICHE_QUIC_CORE_QPACK_QPACK_PROGRESSIVE_DECODER_H_
