polardbxengine/plugin/x/protocol/encoders/encoding_xprotocol.h

354 lines
11 KiB
C++

/*
* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2.0,
* as published by the Free Software Foundation.
*
* This program is also distributed with certain software (including
* but not limited to OpenSSL) that is licensed under separate terms,
* as designated in a particular file or component or in included license
* documentation. The authors of MySQL hereby grant you an additional
* permission to link the program and your derivative works with the
* separately licensed software that they have included with MySQL.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License, version 2.0, for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef PLUGIN_X_PROTOCOL_ENCODERS_ENCODING_XPROTOCOL_H_
#define PLUGIN_X_PROTOCOL_ENCODERS_ENCODING_XPROTOCOL_H_
#include <google/protobuf/wire_format_lite.h>
#include <cassert>
#include <cstdint>
#include <string>
#include "my_dbug.h"
#include "plugin/x/protocol/encoders/encoding_protobuf.h"
namespace protocol {
namespace tags {
enum Raw_payload_ids {
COMPRESSION_SINGLE = 19,
COMPRESSION_MULTIPLE = 20,
COMPRESSION_GROUP = 21,
};
} // namespace tags
enum class Compression_type { k_single, k_multiple, k_group };
class Compression_buffer_interface {
public:
virtual ~Compression_buffer_interface() = default;
virtual void reset_counters() = 0;
virtual bool process(Encoding_buffer *output_buffer,
const Encoding_buffer *input_buffer) = 0;
virtual void get_processed_data(uint32_t *out_uncompressed,
uint32_t *out_compressed) = 0;
};
/**
This class is wraps protobuf payload with X Protocol header
This class generates X Protocol headers for protobuf messages
and for compressed messages.
Additionally it supplies sub-field protobuf functionality,
because similar mechanism was used for generation for protobuf
fields and X headers.
*/
class XProtocol_encoder : public Protobuf_encoder {
private:
constexpr static uint32_t k_xmessage_header_length = 5;
enum class Header_configuration { k_full, k_size_only, k_none };
Header_configuration m_header_configuration = Header_configuration::k_full;
uint32_t m_header_size = header_size(m_header_configuration);
void set_header_config(const Header_configuration config) {
m_header_configuration = config;
m_header_size = header_size(m_header_configuration);
}
static uint32_t header_size(const Header_configuration config) {
switch (config) {
case Header_configuration::k_full:
return 5;
case Header_configuration::k_none:
return 0;
case Header_configuration::k_size_only:
return 4;
default:
assert(false && "Not allowed value");
return 0;
}
}
public:
explicit XProtocol_encoder(Encoding_buffer *buffer)
: Protobuf_encoder(buffer) {
ensure_buffer_size<1>();
}
struct Position {
Page *m_page;
uint8_t *m_position;
uint8_t *get_position() const { return m_position; }
uint32_t bytes_until_page(Page *current_page) const {
uint32_t size = m_page->m_current_data - m_position;
if (current_page == m_page) {
return size;
}
Page *i = m_page->m_next_page;
for (;;) {
assert(nullptr != i);
size += i->get_used_bytes();
if (i == current_page) {
assert(nullptr == i->m_next_page);
break;
}
i = i->m_next_page;
}
return size;
}
};
template <uint32_t delimiter_length>
struct Field_delimiter : Position {};
struct Compression_position : Position {
Encoding_buffer *m_compressed_buffer;
Compression_type m_compression_type;
uint32_t m_compressed_data_size;
uint32_t m_uncompressed_data_size;
uint8_t m_msg_id;
};
template <uint32_t id>
void empty_xmessage() {
ensure_buffer_size<k_xmessage_header_length>();
if (Header_configuration::k_full == m_header_configuration) {
DBUG_LOG("debug", "empty_msg_full_header");
primitives::base::Fixint_length<4>::encode<1>(m_page->m_current_data);
primitives::base::Fixint_length<1>::encode<id>(m_page->m_current_data);
} else if (Header_configuration::k_size_only == m_header_configuration) {
DBUG_LOG("debug", "empty_msg_size_only");
primitives::base::Fixint_length<4>::encode<0>(m_page->m_current_data);
}
}
Compression_position begin_compression(const uint8_t msg_id,
const Compression_type type,
Encoding_buffer *to_compress) {
Compression_position result;
switch (type) {
case Compression_type::k_single:
begin_xmessage<tags::Raw_payload_ids::COMPRESSION_SINGLE, 100>(&result);
set_header_config(Header_configuration::k_none);
m_buffer->m_current->m_current_data += 5;
break;
case Compression_type::k_multiple:
begin_xmessage<tags::Raw_payload_ids::COMPRESSION_MULTIPLE, 100>(
&result);
set_header_config(Header_configuration::k_size_only);
m_buffer->m_current->m_current_data += 5;
break;
case Compression_type::k_group:
begin_xmessage<tags::Raw_payload_ids::COMPRESSION_GROUP, 100>(&result);
set_header_config(Header_configuration::k_full);
m_buffer->m_current->m_current_data += 4;
break;
}
DBUG_ASSERT(to_compress->m_current == to_compress->m_front);
DBUG_ASSERT(to_compress->m_current->m_begin_data ==
to_compress->m_current->m_current_data);
result.m_compressed_buffer = m_buffer;
result.m_compression_type = type;
result.m_msg_id = msg_id;
// Reset buffer, and initialize the 'handy' data hold inside
// 'Encoder_primitives'
buffer_set(to_compress);
return result;
}
bool end_compression(const Compression_position &position,
Compression_buffer_interface *compress) {
Position before_compression{m_buffer->m_front,
m_buffer->m_front->m_begin_data};
const auto before_compression_size =
before_compression.bytes_until_page(m_page);
if (!compress->process(position.m_compressed_buffer, m_buffer))
return false;
auto ptr = position.m_position;
const auto message_size =
position.bytes_until_page(position.m_compressed_buffer->m_current);
switch (position.m_compression_type) {
case Compression_type::k_single:
primitives::base::Fixint_length<4>::encode_value(ptr, message_size - 4);
primitives::base::Fixint_length<1>::encode_value(
ptr, tags::Raw_payload_ids::COMPRESSION_SINGLE);
primitives::base::Fixint_length<1>::encode_value(ptr,
position.m_msg_id);
primitives::base::Fixint_length<4>::encode_value(
ptr, before_compression_size);
break;
case Compression_type::k_multiple:
primitives::base::Fixint_length<4>::encode_value(ptr, message_size - 4);
primitives::base::Fixint_length<1>::encode_value(
ptr, tags::Raw_payload_ids::COMPRESSION_MULTIPLE);
primitives::base::Fixint_length<1>::encode_value(ptr,
position.m_msg_id);
primitives::base::Fixint_length<4>::encode_value(
ptr, before_compression_size);
break;
case Compression_type::k_group:
primitives::base::Fixint_length<4>::encode_value(ptr, message_size - 4);
primitives::base::Fixint_length<1>::encode_value(
ptr, tags::Raw_payload_ids::COMPRESSION_GROUP);
primitives::base::Fixint_length<4>::encode_value(
ptr, before_compression_size);
break;
}
// Lets discard data inside new/compression buffer
// in case when 'compress' call didn't do that.
m_buffer->reset();
// and now we restore original buffer
buffer_set(position.m_compressed_buffer);
set_header_config(Header_configuration::k_full);
return true;
}
template <uint32_t id, uint32_t needed_buffer_size>
Position begin_xmessage() {
Position result;
begin_xmessage<id, needed_buffer_size>(&result);
return result;
}
template <uint32_t needed_buffer_size>
Position begin_xmessage(const uint32_t id) {
Position result;
ensure_buffer_size<needed_buffer_size + k_xmessage_header_length>();
auto xmsg_start = m_page->m_current_data;
if (Header_configuration::k_full == m_header_configuration) {
auto xmsg_type = xmsg_start + 4;
primitives::base::Fixint_length<1>::encode_value(xmsg_type, id);
}
result.m_page = m_page;
result.m_position = xmsg_start;
m_page->m_current_data += m_header_size;
return result;
}
template <uint32_t id, uint32_t needed_buffer_size>
void begin_xmessage(Position *position) {
ensure_buffer_size<needed_buffer_size + k_xmessage_header_length>();
auto xmsg_start = m_page->m_current_data;
if (Header_configuration::k_full == m_header_configuration) {
auto xmsg_type = xmsg_start + 4;
primitives::base::Fixint_length<1>::encode<id>(xmsg_type);
}
position->m_page = m_page;
position->m_position = xmsg_start;
m_page->m_current_data += m_header_size;
}
void end_xmessage(const Position &position) {
auto ptr = position.get_position();
if (Header_configuration::k_none != m_header_configuration) {
primitives::base::Fixint_length<4>::encode_value(
ptr, position.bytes_until_page(m_page) - 4);
}
}
void abort_xmessage(const Position &position) {
auto page = position.m_page->m_next_page;
m_buffer->remove_page_list(page);
m_page = position.m_page;
m_page->m_current_data = position.m_position;
}
void abort_compression(const Compression_position &position) {
// Lets discard data inside new/compression buffer
// in case when 'compress' call didn't do that.
m_buffer->reset();
// and now we restore original buffer
buffer_set(position.m_compressed_buffer);
set_header_config(Header_configuration::k_full);
abort_xmessage(position);
}
template <uint32_t id, uint32_t delimiter_length = 1>
Field_delimiter<delimiter_length> begin_delimited_field() {
Field_delimiter<delimiter_length> result;
begin_delimited_field<id>(&result);
return result;
}
template <uint32_t id, uint32_t delimiter_length = 1>
void begin_delimited_field(Field_delimiter<delimiter_length> *position) {
encode_field_delimited_header<id>();
position->m_position = m_page->m_current_data;
position->m_page = m_page;
m_page->m_current_data += delimiter_length;
}
template <uint32_t delimiter_length>
void end_delimited_field(const Field_delimiter<delimiter_length> &position) {
auto ptr = position.get_position();
primitives::base::Varint_length<delimiter_length>::encode(
ptr, position.bytes_until_page(m_page) - delimiter_length);
}
};
} // namespace protocol
#endif // PLUGIN_X_PROTOCOL_ENCODERS_ENCODING_XPROTOCOL_H_