MySQL 8.3.0
Source Code Documentation
gcs_internal_message.h
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1/* Copyright (c) 2016, 2023, Oracle and/or its affiliates.
2
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4 it under the terms of the GNU General Public License, version 2.0,
5 as published by the Free Software Foundation.
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12 separately licensed software that they have included with MySQL.
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15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License, version 2.0, for more details.
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20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
22
23#ifndef GCS_MSG_H
24#define GCS_MSG_H
25
26#include <cassert>
27#include <cstdlib>
28#include <memory>
29#include <sstream>
30#include <unordered_set>
31#include <vector>
34
36
38
39/**
40 Deleter for objects managed by a std::unique_ptr that were allocated using
41 the malloc family of functions instead of the new operator.
42 */
44 void operator()(unsigned char *buffer) const { std::free(buffer); }
45};
46
47/**
48 This class is an abstraction for the packet concept. It is used to manipulate
49 the contents of a buffer that is to be sent to the network in an optimal way.
50
51 The on-the-wire layout looks like this:
52
53 +--------------+-----------------+----------------+-----------+
54 | fixed header | dynamic headers | stage metadata | payload |
55 +--------------+-----------------+----------------+-----------+
56 */
58 public:
59 using buffer_ptr = std::unique_ptr<unsigned char, Gcs_packet_buffer_deleter>;
60
61 private:
62 /**
63 Fixed header which is common regardless whether the packet has been
64 changed by a stage or not.
65 */
67
68 /**
69 List of dynamic headers created by the stages by which the packet has
70 passed through and changed it.
71 */
72 std::vector<Gcs_dynamic_header> m_dynamic_headers;
73
74 /**
75 List of stage metadata created by the stages by which the packet has passed
76 through.
77 This list always has the same length as m_dynamic_headers, and the
78 following holds:
79
80 For every i, m_stage_metadata[i] and m_dynamic_headers[i] correspond to
81 the same stage.
82 */
83 std::vector<std::unique_ptr<Gcs_stage_metadata>> m_stage_metadata;
84
85 /**
86 Index of the next stage to apply/revert in both m_dynamic_headers and
87 m_stage_metadata.
88 */
89 std::size_t m_next_stage_index{0};
90
91 /**
92 The buffer containing all serialized data for this packet.
93 */
95
96 /**
97 The capacity of the serialization buffer.
98 */
99 unsigned long long m_serialized_packet_size{0};
100
101 /**
102 The offset in m_serialized_packet where the application payload starts.
103 */
105
106 /**
107 The size of the serialized application payload in m_serialized_packet.
108 */
109 unsigned long long m_serialized_payload_size{0};
110
111 /**
112 The size of the serialized m_stage_metadata in m_serialized_packet.
113 */
114 unsigned long long m_serialized_stage_metadata_size{0};
115
116 /**
117 The XCom synode in which this packet was delivered.
118 */
120
121 /**
122 The XCom synode in which this packet was delivered.
123 */
125
126 public:
127 /**
128 This factory method is to be used when sending a packet.
129
130 @param cargo The message type
131 @param current_version The pipeline version
132 @param dynamic_headers The dynamic headers of the stages the packet will go
133 through
134 @param stage_metadata The stage metadata of the stages the packet will go
135 through
136 @param payload_size The payload size
137 @retval {true, Gcs_packet} If packet is created successfully
138 @retval {false, _} If memory could not be allocated
139 */
140 static std::pair<bool, Gcs_packet> make_outgoing_packet(
141 Cargo_type const &cargo, Gcs_protocol_version const &current_version,
142 std::vector<Gcs_dynamic_header> &&dynamic_headers,
143 std::vector<std::unique_ptr<Gcs_stage_metadata>> &&stage_metadata,
144 unsigned long long const &payload_size);
145
146 /**
147 This factory method is to be used when modifying a packet. This builds a
148 packet with all the same headers, metadata, and state of @c original_packet.
149
150 It is used, for example, by:
151 - The compression stage of the pipeline, to derive the compressed packet from
152 the original, uncompressed packet.
153 - The fragmentation stage of the pipeline, to derive the fragments from the
154 original packet.
155
156 @param original_packet The packet to "clone"
157 @param new_payload_size The payload size of this packet
158 @retval {true, Gcs_packet} If packet is created successfully
159 @retval {false, _} If memory could not be allocated
160 */
161 static std::pair<bool, Gcs_packet> make_from_existing_packet(
162 Gcs_packet const &original_packet,
163 unsigned long long const &new_payload_size);
164
165 /**
166 This factory method is to be used when receiving a packet from the network.
167
168 @param buffer Buffer with a serialized packet
169 @param buffer_size Size of the buffer
170 @param delivery_synode The XCom synode where the packet was decided on
171 @param origin_synode The XCom synode that identifies the origin of the packet
172 @param pipeline The message pipeline
173 @returns A packet initialized from the buffer
174 */
176 unsigned long long buffer_size,
177 synode_no const &delivery_synode,
178 synode_no const &origin_synode,
179 Gcs_message_pipeline const &pipeline);
180
181 Gcs_packet() noexcept;
182
183 /**
184 These constructors are to be used when move semantics may be needed.
185 */
186 Gcs_packet(Gcs_packet &&packet) noexcept;
187 Gcs_packet &operator=(Gcs_packet &&packet) noexcept;
188
189 Gcs_packet(const Gcs_packet &packet) = delete;
190 Gcs_packet &operator=(const Gcs_packet &packet) = delete;
191
192 /**
193 Retrieve this packet's header.
194 @returns The packet's header
195 */
197
198 /**
199 Retrieve this packet's dynamic headers.
200 @returns The packet's dynamic headers
201 */
203
204 /**
205 Retrieve this packet's stage metadata.
206 @returns The packet's stage metadata
207 */
209 const;
210
211 std::size_t const &get_next_stage_index() const;
212
215
217
219
220 unsigned char *get_payload_pointer();
221
222 void set_payload_length(unsigned long long const &new_length);
223
224 /**
225 Return the value of the maximum supported version.
226 */
228
229 /**
230 Return the value of the version in use.
231 */
233
234 /**
235 Return the cargo type.
236 */
238
239 /**
240 Return the total length.
241 */
242 unsigned long long get_total_length() const;
243
244 /**
245 Return the payload length.
246 */
247 unsigned long long const &get_payload_length() const;
248
249 /**
250 Encode the packet content into its serialization buffer, and release
251 ownership of the serialization buffer.
252
253 This method must only be called on a valid packet, i.e. a packet for which
254 @c allocate_serialization_buffer was called and returned true.
255
256 @retval {buffer, buffer_size} The buffer with the serialized packet, and
257 its size
258 */
259 std::pair<buffer_ptr, unsigned long long> serialize();
260
261 /**
262 Create a string representation of the packet to be logged.
263
264 @param output Reference to the output stream where the string will be
265 created.
266 */
267 void dump(std::ostringstream &output) const;
268
270
271 Gcs_xcom_synode const &get_origin_synode() const;
272
273 private:
274 /**
275 Constructor called by @c make_to_send.
276
277 @param cargo The message type
278 @param current_version The pipeline version
279 @param dynamic_headers The dynamic headers of the stages the packet will go
280 through
281 @param stage_metadata The stage metadata of the stages the packet will go
282 through
283 @param payload_size The payload size
284 */
285 explicit Gcs_packet(
286 Cargo_type const &cargo, Gcs_protocol_version const &current_version,
287 std::vector<Gcs_dynamic_header> &&dynamic_headers,
288 std::vector<std::unique_ptr<Gcs_stage_metadata>> &&stage_metadata,
289 unsigned long long const &payload_size);
290
291 /**
292 Constructor called by @c make_from_existing_packet.
293
294 @param original_packet The packet to "clone"
295 @param new_payload_size The payload size of this packet
296 */
297 explicit Gcs_packet(Gcs_packet const &original_packet,
298 unsigned long long const &new_payload_size);
299
300 /**
301 Constructor called by @c make_from_serialized_buffer.
302
303 @param delivery_synode The XCom synode where the packet was decided on
304 @param origin_synode The XCom synode that identifieis the origin of this
305 packet
306 */
307 explicit Gcs_packet(synode_no const &delivery_synode,
308 synode_no const &origin_synode);
309
310 /**
311 Allocates the underlying buffer where the packet will be serialized to using
312 @c serialize.
313
314 @returns true if the required buffer could not be allocated, false otherwise
315 */
317
318 /**
319 Decode the packet content from the given buffer containing a serialized
320 packet.
321
322 @param buffer Buffer containing a serialized packet
323 @param buffer_size Size of the buffer
324 @param pipeline The message pipeline
325 */
326 void deserialize(buffer_ptr &&buffer, unsigned long long buffer_size,
327 Gcs_message_pipeline const &pipeline);
328};
329
330#endif // GCS_MSG_H
This is a default header created per stage and contains information to decode it.
Definition: gcs_internal_message_headers.h:426
This header is internal to the MySQL GCS library and contains metadata information about the message ...
Definition: gcs_internal_message_headers.h:178
This is the pipeline that an outgoing or incoming message has to go through when being sent to or rec...
Definition: gcs_message_stages.h:364
This class is an abstraction for the packet concept.
Definition: gcs_internal_message.h:57
static std::pair< bool, Gcs_packet > make_from_existing_packet(Gcs_packet const &original_packet, unsigned long long const &new_payload_size)
This factory method is to be used when modifying a packet.
Definition: gcs_internal_message.cc:98
void set_payload_length(unsigned long long const &new_length)
Definition: gcs_internal_message.cc:247
Gcs_internal_message_header m_fixed_header
Fixed header which is common regardless whether the packet has been changed by a stage or not.
Definition: gcs_internal_message.h:66
buffer_ptr m_serialized_packet
The buffer containing all serialized data for this packet.
Definition: gcs_internal_message.h:94
std::vector< Gcs_dynamic_header > m_dynamic_headers
List of dynamic headers created by the stages by which the packet has passed through and changed it.
Definition: gcs_internal_message.h:72
Gcs_protocol_version get_used_version() const
Return the value of the version in use.
Definition: gcs_internal_message.cc:257
std::size_t m_serialized_payload_offset
The offset in m_serialized_packet where the application payload starts.
Definition: gcs_internal_message.h:104
std::vector< Gcs_dynamic_header > const & get_dynamic_headers() const
Retrieve this packet's dynamic headers.
Definition: gcs_internal_message.cc:217
void prepare_for_next_outgoing_stage()
Definition: gcs_internal_message.cc:231
static std::pair< bool, Gcs_packet > make_outgoing_packet(Cargo_type const &cargo, Gcs_protocol_version const &current_version, std::vector< Gcs_dynamic_header > &&dynamic_headers, std::vector< std::unique_ptr< Gcs_stage_metadata > > &&stage_metadata, unsigned long long const &payload_size)
This factory method is to be used when sending a packet.
Definition: gcs_internal_message.cc:42
void dump(std::ostringstream &output) const
Create a string representation of the packet to be logged.
Definition: gcs_internal_message.cc:374
std::size_t m_next_stage_index
Index of the next stage to apply/revert in both m_dynamic_headers and m_stage_metadata.
Definition: gcs_internal_message.h:89
Gcs_xcom_synode m_delivery_synode
The XCom synode in which this packet was delivered.
Definition: gcs_internal_message.h:119
unsigned long long const & get_payload_length() const
Return the payload length.
Definition: gcs_internal_message.cc:269
Gcs_xcom_synode const & get_origin_synode() const
Definition: gcs_internal_message.cc:390
Gcs_xcom_synode const & get_delivery_synode() const
Definition: gcs_internal_message.cc:386
Gcs_packet() noexcept
Definition: gcs_internal_message.cc:29
static Gcs_packet make_incoming_packet(buffer_ptr &&buffer, unsigned long long buffer_size, synode_no const &delivery_synode, synode_no const &origin_synode, Gcs_message_pipeline const &pipeline)
This factory method is to be used when receiving a packet from the network.
Definition: gcs_internal_message.cc:142
Gcs_xcom_synode m_origin_synode
The XCom synode in which this packet was delivered.
Definition: gcs_internal_message.h:124
Gcs_stage_metadata & get_current_stage_header()
Definition: gcs_internal_message.cc:239
std::vector< std::unique_ptr< Gcs_stage_metadata > > const & get_stage_metadata() const
Retrieve this packet's stage metadata.
Definition: gcs_internal_message.cc:223
void deserialize(buffer_ptr &&buffer, unsigned long long buffer_size, Gcs_message_pipeline const &pipeline)
Decode the packet content from the given buffer containing a serialized packet.
Definition: gcs_internal_message.cc:323
unsigned long long m_serialized_payload_size
The size of the serialized application payload in m_serialized_packet.
Definition: gcs_internal_message.h:109
std::vector< std::unique_ptr< Gcs_stage_metadata > > m_stage_metadata
List of stage metadata created by the stages by which the packet has passed through.
Definition: gcs_internal_message.h:83
unsigned long long m_serialized_stage_metadata_size
The size of the serialized m_stage_metadata in m_serialized_packet.
Definition: gcs_internal_message.h:114
std::unique_ptr< unsigned char, Gcs_packet_buffer_deleter > buffer_ptr
Definition: gcs_internal_message.h:59
void prepare_for_next_incoming_stage()
Definition: gcs_internal_message.cc:233
Gcs_internal_message_header const & get_fixed_header() const
Retrieve this packet's header.
Definition: gcs_internal_message.cc:213
unsigned long long get_total_length() const
Return the total length.
Definition: gcs_internal_message.cc:265
Cargo_type get_cargo_type() const
Return the cargo type.
Definition: gcs_internal_message.cc:261
unsigned long long m_serialized_packet_size
The capacity of the serialization buffer.
Definition: gcs_internal_message.h:99
bool allocate_serialization_buffer()
Allocates the underlying buffer where the packet will be serialized to using serialize.
Definition: gcs_internal_message.cc:273
unsigned char * get_payload_pointer()
Definition: gcs_internal_message.cc:243
Gcs_protocol_version get_maximum_version() const
Return the value of the maximum supported version.
Definition: gcs_internal_message.cc:253
std::pair< buffer_ptr, unsigned long long > serialize()
Encode the packet content into its serialization buffer, and release ownership of the serialization b...
Definition: gcs_internal_message.cc:292
Gcs_dynamic_header & get_current_dynamic_header()
Definition: gcs_internal_message.cc:235
std::size_t const & get_next_stage_index() const
Definition: gcs_internal_message.cc:227
Abstract class that defines specific metadata associated to a stage if it decides to extend it.
Definition: gcs_internal_message_headers.h:561
Defines a message identifier so that joining members can fetch the associated packet from a remote no...
Definition: gcs_xcom_synode.h:38
Cargo_type
The different cargo type codes.
Definition: gcs_internal_message_headers.h:114
Gcs_protocol_version
The GCS protocol versions.
Definition: gcs_types.h:127
#define free(A)
Definition: lexyy.cc:915
mutable_buffer buffer(void *p, size_t n) noexcept
Definition: buffer.h:417
size_t buffer_size(const ConstBufferSequence &buffers) noexcept
Definition: buffer.h:312
Definition: varlen_sort.h:174
std::basic_ostringstream< char, std::char_traits< char >, ut::allocator< char > > ostringstream
Specialization of basic_ostringstream which uses ut::allocator.
Definition: ut0new.h:2869
std::vector< T, ut::allocator< T > > vector
Specialization of vector which uses allocator.
Definition: ut0new.h:2873
std::conditional_t< !std::is_array< T >::value, std::unique_ptr< T, detail::Deleter< T > >, std::conditional_t< detail::is_unbounded_array_v< T >, std::unique_ptr< T, detail::Array_deleter< std::remove_extent_t< T > > >, void > > unique_ptr
The following is a common type that is returned by all the ut::make_unique (non-aligned) specializati...
Definition: ut0new.h:2437
Deleter for objects managed by a std::unique_ptr that were allocated using the malloc family of funct...
Definition: gcs_internal_message.h:43
void operator()(unsigned char *buffer) const
Definition: gcs_internal_message.h:44