service_command.h File Reference

Header file for the Command service. More...

#include "mysql/com_data.h"
#include "mysql/service_srv_session.h"
#include "decimal.h"
#include "mysql_time.h"
#include <stdint.h>
#include "field_types.h"
#include "mysql/strings/m_ctype.h"

Go to the source code of this file.

Classes
struct	st_send_field
struct	st_command_service_cbs
struct	command_service_st

Typedefs
typedef int(*	start_result_metadata_t) (void *ctx, uint num_cols, uint flags, const CHARSET_INFO *resultcs)
	Indicates beginning of metadata for the result set. More...
typedef int(*	field_metadata_t) (void *ctx, struct st_send_field *field, const CHARSET_INFO *charset)
	Field metadata is provided via this callback. More...
typedef int(*	end_result_metadata_t) (void *ctx, uint server_status, uint warn_count)
	Indicates end of metadata for the result set. More...
typedef int(*	start_row_t) (void *ctx)
	Indicates the beginning of a new row in the result set/metadata. More...
typedef int(*	end_row_t) (void *ctx)
	Indicates the end of the current row in the result set/metadata. More...
typedef void(*	abort_row_t) (void *ctx)
	An error occurred during execution. More...
typedef ulong(*	get_client_capabilities_t) (void *ctx)
	Return client's capabilities (see mysql_com.h, CLIENT_*) More...
typedef int(*	get_null_t) (void *ctx)
	Receive NULL value from server. More...
typedef int(*	get_integer_t) (void *ctx, longlong value)
	Receive TINY/SHORT/LONG value from server. More...
typedef int(*	get_longlong_t) (void *ctx, longlong value, uint is_unsigned)
	Get LONGLONG value from server. More...
typedef int(*	get_decimal_t) (void *ctx, const decimal_t *value)
	Receive DECIMAL value from server. More...
typedef int(*	get_double_t) (void *ctx, double value, uint32_t decimals)
	Receive FLOAT/DOUBLE from server. More...
typedef int(*	get_date_t) (void *ctx, const MYSQL_TIME *value)
	Get DATE value from server. More...
typedef int(*	get_time_t) (void *ctx, const MYSQL_TIME *value, uint decimals)
	Receive TIME value from server. More...
typedef int(*	get_datetime_t) (void *ctx, const MYSQL_TIME *value, uint decimals)
	Receive DATETIME value from server. More...
typedef int(*	get_string_t) (void *ctx, const char *value, size_t length, const CHARSET_INFO *valuecs)
	Get STRING value from server. More...
typedef void(*	handle_ok_t) (void *ctx, uint server_status, uint statement_warn_count, ulonglong affected_rows, ulonglong last_insert_id, const char *message)
	Command ended with success. More...
typedef void(*	handle_error_t) (void *ctx, uint sql_errno, const char *err_msg, const char *sqlstate)
	Command ended with ERROR. More...
typedef void(*	shutdown_t) (void *ctx, int server_shutdown)
	Callback for shutdown notification from the server. More...
typedef bool(*	connection_alive_t) (void *ctx)
	If the user of the srv_service is bound to a connection, this callback makes it possible to check if the connection is still alive. More...

Enumerations
enum	cs_text_or_binary { CS_TEXT_REPRESENTATION = 1 , CS_BINARY_REPRESENTATION = 2 }

Functions
int	command_service_run_command (MYSQL_SESSION session, enum enum_server_command command, const union COM_DATA *data, const CHARSET_INFO *client_cs, const struct st_command_service_cbs *callbacks, enum cs_text_or_binary text_or_binary, void *service_callbacks_ctx)
	Executes a server command in a session. More...

Variables
struct command_service_st *	command_service

Detailed Description

Header file for the Command service.

This service is to provide means of executing different commands, like COM_QUERY, COM_STMT_PREPARE, in the server.

Typedef Documentation

abort_row_t

typedef void(* abort_row_t) (void *ctx)

An error occurred during execution.

This callback indicates that an error occurred during command execution and the partial row should be dropped. Server will raise error and return.

Parameters

ctx	Plugin's context

connection_alive_t

typedef bool(* connection_alive_t) (void *ctx)

If the user of the srv_service is bound to a connection, this callback makes it possible to check if the connection is still alive.

It should always return true unless the client closed the connection.

Returns

true if the connection is still alive false otherwise

end_result_metadata_t

typedef int(* end_result_metadata_t) (void *ctx, uint server_status, uint warn_count)

Indicates end of metadata for the result set.

Parameters

ctx	Plugin's context
server_status	Status of server (see mysql_com.h, SERVER_STATUS_*)
warn_count	Number of warnings generated during execution to the moment when the metadata is sent.

Returns

1 an error occurred, server will abort the command 0 ok

end_row_t

typedef int(* end_row_t) (void *ctx)

Indicates the end of the current row in the result set/metadata.

Parameters

ctx	Plugin's context

Returns

1 an error occurred, server will abort the command 0 ok

field_metadata_t

typedef int(* field_metadata_t) (void *ctx, struct st_send_field *field, const CHARSET_INFO *charset)

Field metadata is provided via this callback.

Parameters

ctx	Plugin's context
field	Field's metadata (see field.h)
charset	Field's charset

Returns

1 an error occurred, server will abort the command 0 ok

get_client_capabilities_t

typedef ulong(* get_client_capabilities_t) (void *ctx)

Return client's capabilities (see mysql_com.h, CLIENT_*)

Parameters

ctx	Plugin's context

Returns

Bitmap of client's capabilities

get_date_t

typedef int(* get_date_t) (void *ctx, const MYSQL_TIME *value)

Get DATE value from server.

Parameters

ctx	Plugin's context
value	Value received

Returns

1 an error occurred during storing, server will abort the command 0 ok

get_datetime_t

typedef int(* get_datetime_t) (void *ctx, const MYSQL_TIME *value, uint decimals)

Receive DATETIME value from server.

Parameters

ctx	Plugin's context
value	Value received
decimals	Number of decimals

Returns

1 an error occurred during storing, server will abort the command 0 ok

get_decimal_t

typedef int(* get_decimal_t) (void *ctx, const decimal_t *value)

Receive DECIMAL value from server.

Parameters

ctx	Plugin's context
value	Value received

Returns

1 an error occurred, server will abort the command 0 ok

get_double_t

typedef int(* get_double_t) (void *ctx, double value, uint32_t decimals)

Receive FLOAT/DOUBLE from server.

Parameters

ctx	Plugin's context
value	Value received
decimals	Number of decimals

Note

In order to know which type exactly was received, the plugin must track the metadata that was sent just prior to the result set.

Returns

1 an error occurred, server will abort the command 0 ok

get_integer_t

typedef int(* get_integer_t) (void *ctx, longlong value)

Receive TINY/SHORT/LONG value from server.

Parameters

ctx	Plugin's context
value	Value received

Note

In order to know which type exactly was received, the plugin must track the metadata that was sent just prior to the result set.

Returns

1 an error occurred, server will abort the command 0 ok

get_longlong_t

typedef int(* get_longlong_t) (void *ctx, longlong value, uint is_unsigned)

Get LONGLONG value from server.

Parameters

ctx	Plugin's context
value	Value received
is_unsigned	TRUE <=> value is unsigned

Returns

1 an error occurred, server will abort the command 0 ok

get_null_t

typedef int(* get_null_t) (void *ctx)

Receive NULL value from server.

Parameters

ctx	Plugin's context

Returns

1 an error occurred, server will abort the command 0 ok

get_string_t

typedef int(* get_string_t) (void *ctx, const char *value, size_t length, const CHARSET_INFO *valuecs)

Get STRING value from server.

Parameters

ctx	Plugin's context
value	Data
length	Data length
valuecs	Data charset

Note

In case of CS_BINARY_REPRESENTATION, get_string() receives as a parameter the charset of the string, as it is stored on disk.

In case of CS_TEXT_REPRESENTATION, the string value might be already a stringified value or non-string data, which is in character_set_results.

See also

start_result_metadata()

Returns

1 an error occurred, server will abort the command 0 ok

get_time_t

typedef int(* get_time_t) (void *ctx, const MYSQL_TIME *value, uint decimals)

Receive TIME value from server.

Parameters

ctx	Plugin's context
value	Value received
decimals	Number of decimals

Returns

1 an error occurred during storing, server will abort the command 0 ok

handle_error_t

typedef void(* handle_error_t) (void *ctx, uint sql_errno, const char *err_msg, const char *sqlstate)

Command ended with ERROR.

Parameters

ctx	Plugin's context
sql_errno	Error code
err_msg	Error message
sqlstate	SQL state corresponding to the error code

handle_ok_t

typedef void(* handle_ok_t) (void *ctx, uint server_status, uint statement_warn_count, ulonglong affected_rows, ulonglong last_insert_id, const char *message)

Command ended with success.

Parameters

ctx	Plugin's context
server_status	Status of server (see mysql_com.h, SERVER_STATUS_*)
statement_warn_count	Number of warnings thrown during execution
affected_rows	Number of rows affected by the command
last_insert_id	Last insert id being assigned during execution
message	A message from server

shutdown_t

typedef void(* shutdown_t) (void *ctx, int server_shutdown)

Callback for shutdown notification from the server.

Parameters

ctx	Plugin's context
server_shutdown	Whether this is a normal connection shutdown (0) or server shutdown (1).

start_result_metadata_t

typedef int(* start_result_metadata_t) (void *ctx, uint num_cols, uint flags, const CHARSET_INFO *resultcs)

Indicates beginning of metadata for the result set.

Parameters

ctx	Plugin's context
num_cols	Number of fields being sent
flags	Flags to alter the metadata sending
resultcs	Charset of the result set

Note

resultcs is the charset in which the data should be encoded before sent to the client. This is the value of the session variable character_set_results. The implementor most probably will need to save this value in the context and use it as "to" charset in get_string().

In case of CS_BINARY_REPRESENTATION, get_string() receives as a parameter the charset of the string, as it is stored on disk.

In case of CS_TEXT_REPRESENTATION, the string value might be already a stringified value or non-string data, which is in character_set_results.

Returns

1 an error occurred, server will abort the command 0 ok

start_row_t

typedef int(* start_row_t) (void *ctx)

Indicates the beginning of a new row in the result set/metadata.

Parameters

ctx	Plugin's context

Returns

1 an error occurred, server will abort the command 0 ok

Enumeration Type Documentation

cs_text_or_binary

enum cs_text_or_binary

Enumerator
CS_TEXT_REPRESENTATION
CS_BINARY_REPRESENTATION

Function Documentation

command_service_run_command()

int command_service_run_command	(	MYSQL_SESSION	session,
		enum enum_server_command	command,
		const union COM_DATA *	data,
		const CHARSET_INFO *	client_cs,
		const struct st_command_service_cbs *	callbacks,
		enum cs_text_or_binary	text_or_binary,
		void *	service_callbacks_ctx
	)

Executes a server command in a session.

There are two cases. Execution in a physical thread :

1. initialized by the srv_session service
2. NOT initialized by the srv_session service

In case of 1, if there is currently attached session, and it is different from the passed one, the former will be automatically detached. The session to be used for the execution will then be attached. After the command is executed, the attached session will not be detached. It will be detached by a next call to run_command() with another session as parameter. In other words, for all sessions used in a physical thread, there will be at most one in attached state.

In case of 2, the current state (current_thd) will be preserved. Then the given session will move to attached state and the command will be executed. After the execution the state of the session will be changed to detached and the preserved state (current_thd) will be restored.

The client charset is used for commands like COM_QUERY and COM_STMT_PREPARE to know how to threat the char* fields. This charset will be used until the next call of run_command when it may be changed again.

Parameters

session	The session
command	The command to be executed.
data	The data needed for the command to be executed
client_cs	The charset for the string data input(COM_QUERY for example)
callbacks	Callbacks to be used by the server to encode data and to communicate with the client (plugin) side.
text_or_binary	Select which representation the server will use for the data passed to the callbacks. For more information

See also

cs_text_or_binary enum

Parameters

service_callbacks_ctx

Context passed to the command service callbacks

Returns

0 success 1 failure

Variable Documentation

command_service

struct command_service_st * command_service