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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_ENCODER_H_
#define QUICHE_QUIC_CORE_QPACK_QPACK_ENCODER_H_
#include <cstdint>
#include <memory>
#include <string>
#include <vector>
#include "absl/strings/string_view.h"
#include "quic/core/qpack/qpack_blocking_manager.h"
#include "quic/core/qpack/qpack_decoder_stream_receiver.h"
#include "quic/core/qpack/qpack_encoder_stream_sender.h"
#include "quic/core/qpack/qpack_header_table.h"
#include "quic/core/qpack/qpack_instructions.h"
#include "quic/core/quic_error_codes.h"
#include "quic/core/quic_types.h"
#include "quic/platform/api/quic_export.h"
#include "quic/platform/api/quic_exported_stats.h"
#include "spdy/core/spdy_header_block.h"
namespace quic {
namespace test {
class QpackEncoderPeer;
} // namespace test
// QPACK encoder class. Exactly one instance should exist per QUIC connection.
class QUIC_EXPORT_PRIVATE QpackEncoder
: public QpackDecoderStreamReceiver::Delegate {
public:
// Interface for receiving notification that an error has occurred on the
// decoder stream. This MUST be treated as a connection error of type
// HTTP_QPACK_DECODER_STREAM_ERROR.
class QUIC_EXPORT_PRIVATE DecoderStreamErrorDelegate {
public:
virtual ~DecoderStreamErrorDelegate() {}
virtual void OnDecoderStreamError(QuicErrorCode error_code,
absl::string_view error_message) = 0;
};
QpackEncoder(DecoderStreamErrorDelegate* decoder_stream_error_delegate);
~QpackEncoder() override;
// Encode a header list. If |encoder_stream_sent_byte_count| is not null,
// |*encoder_stream_sent_byte_count| will be set to the number of bytes sent
// on the encoder stream to insert dynamic table entries.
std::string EncodeHeaderList(QuicStreamId stream_id,
const spdy::Http2HeaderBlock& header_list,
QuicByteCount* encoder_stream_sent_byte_count);
// Set maximum dynamic table capacity to |maximum_dynamic_table_capacity|,
// measured in bytes. Called when SETTINGS_QPACK_MAX_TABLE_CAPACITY is
// received. Encoder needs to know this value so that it can calculate
// MaxEntries, used as a modulus to encode Required Insert Count.
// Returns true if |maximum_dynamic_table_capacity| is set for the first time
// or if it doesn't change current value. The setting is not changed when
// returning false.
bool SetMaximumDynamicTableCapacity(uint64_t maximum_dynamic_table_capacity);
// Set dynamic table capacity to |dynamic_table_capacity|.
// |dynamic_table_capacity| must not exceed maximum dynamic table capacity.
// Also sends Set Dynamic Table Capacity instruction on encoder stream.
void SetDynamicTableCapacity(uint64_t dynamic_table_capacity);
// Set maximum number of blocked streams.
// Called when SETTINGS_QPACK_BLOCKED_STREAMS is received.
// Returns true if |maximum_blocked_streams| doesn't decrease current value.
// The setting is not changed when returning false.
bool SetMaximumBlockedStreams(uint64_t maximum_blocked_streams);
// QpackDecoderStreamReceiver::Delegate implementation
void OnInsertCountIncrement(uint64_t increment) override;
void OnHeaderAcknowledgement(QuicStreamId stream_id) override;
void OnStreamCancellation(QuicStreamId stream_id) 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) {
encoder_stream_sender_.set_qpack_stream_sender_delegate(delegate);
}
QpackStreamReceiver* decoder_stream_receiver() {
return &decoder_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();
}
uint64_t maximum_blocked_streams() const { return maximum_blocked_streams_; }
uint64_t MaximumDynamicTableCapacity() const {
return header_table_.maximum_dynamic_table_capacity();
}
private:
friend class test::QpackEncoderPeer;
using Representation = QpackInstructionWithValues;
using Representations = std::vector<Representation>;
// Generate indexed header field representation
// and optionally update |*referred_indices|.
static Representation EncodeIndexedHeaderField(
bool is_static,
uint64_t index,
QpackBlockingManager::IndexSet* referred_indices);
// Generate literal header field with name reference representation
// and optionally update |*referred_indices|.
static Representation EncodeLiteralHeaderFieldWithNameReference(
bool is_static,
uint64_t index,
absl::string_view value,
QpackBlockingManager::IndexSet* referred_indices);
// Generate literal header field representation.
static Representation EncodeLiteralHeaderField(absl::string_view name,
absl::string_view value);
// Performs first pass of two-pass encoding: represent each header field in
// |*header_list| as a reference to an existing entry, the name of an existing
// entry with a literal value, or a literal name and value pair. Sends
// necessary instructions on the encoder stream coalesced in a single write.
// Records absolute indices of referred dynamic table entries in
// |*referred_indices|. If |encoder_stream_sent_byte_count| is not null, then
// sets |*encoder_stream_sent_byte_count| to the number of bytes sent on the
// encoder stream to insert dynamic table entries. Returns list of header
// field representations, with all dynamic table entries referred to with
// absolute indices. Returned representation objects may have
// absl::string_views pointing to strings owned by |*header_list|.
Representations FirstPassEncode(
QuicStreamId stream_id,
const spdy::Http2HeaderBlock& header_list,
QpackBlockingManager::IndexSet* referred_indices,
QuicByteCount* encoder_stream_sent_byte_count);
// Performs second pass of two-pass encoding: serializes representations
// generated in first pass, transforming absolute indices of dynamic table
// entries to relative indices.
std::string SecondPassEncode(Representations representations,
uint64_t required_insert_count) const;
DecoderStreamErrorDelegate* const decoder_stream_error_delegate_;
QpackDecoderStreamReceiver decoder_stream_receiver_;
QpackEncoderStreamSender encoder_stream_sender_;
QpackEncoderHeaderTable header_table_;
uint64_t maximum_blocked_streams_;
QpackBlockingManager blocking_manager_;
int header_list_count_;
};
} // namespace quic
#endif // QUICHE_QUIC_CORE_QPACK_QPACK_ENCODER_H_
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