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Streamline query classifier API interface

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- Only types of fixed size used in API interface
- The actual function return value specifies whether the parsing
  process succeeded, while "logical" return values are returned
  as out arguments.

The wrapper function currently ignores the function return value.
This commit is contained in:
Johan Wikman
2017-01-16 14:11:19 +02:00
parent 8d2f4707a4
commit 7fee90a399
6 changed files with 595 additions and 250 deletions
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215
include/maxscale/query_classifier.h
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@ -127,6 +127,16 @@ typedef struct qc_function_info
uint32_t usage; /** Bitfield denoting where the column appears. */
} QC_FUNCTION_INFO;
/**
* Each API function returns @c QC_RESULT_OK if the actual parsing process
* succeeded, and some error code otherwise.
*/
typedef enum qc_result
{
QC_RESULT_OK,
QC_RESULT_ERROR
} qc_result_t;
/**
* QUERY_CLASSIFIER defines the object a query classifier plugin must
* implement and return.
@ -136,29 +146,202 @@ typedef struct qc_function_info
*/
typedef struct query_classifier
{
bool (*qc_setup)(const char* args);
/**
* Called once to setup the query classifier
*
* @param args The value of `query_classifier_args` in the configuration file.
*
* @return QC_RESULT_OK, if the query classifier could be setup, otherwise
* some specific error code.
*/
int32_t (*qc_setup)(const char* args);
int (*qc_process_init)(void);
/**
* Called once at process startup, after @c qc_setup has successfully
* been called.
*
* @return QC_RESULT_OK, if the process initialization succeeded.
*/
int32_t (*qc_process_init)(void);
/**
* Called once at process shutdown.
*/
void (*qc_process_end)(void);
int (*qc_thread_init)(void);
/**
* Called once per each thread, except for the thread for which @c qc_process_init
* was called.
*
* @return QC_RESULT_OK, if the thread initialization succeeded.
*/
int32_t (*qc_thread_init)(void);
/**
* Called once when a thread finishes, except for the thread for which @c qc_process_init
* was called.
*/
void (*qc_thread_end)(void);
qc_parse_result_t (*qc_parse)(GWBUF* stmt);
/**
* Called to explicitly parse a statement.
*
* @param stmt The statement to be parsed.
* @param result On return, the parse result, if @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_parse)(GWBUF* stmt, int32_t* result);
uint32_t (*qc_get_type)(GWBUF* stmt);
qc_query_op_t (*qc_get_operation)(GWBUF* stmt);
/**
* Reports the type of the statement.
*
* @param stmt A statement.
* @param type On return, the type mask (combination of @c qc_query_type_t),
* if @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_type)(GWBUF* stmt, uint32_t* type);
char* (*qc_get_created_table_name)(GWBUF* stmt);
bool (*qc_is_drop_table_query)(GWBUF* stmt);
char** (*qc_get_table_names)(GWBUF* stmt, int* tblsize, bool fullnames);
char* (*qc_get_canonical)(GWBUF* stmt);
bool (*qc_query_has_clause)(GWBUF* stmt);
char** (*qc_get_database_names)(GWBUF* stmt, int* size);
char* (*qc_get_prepare_name)(GWBUF* stmt);
qc_query_op_t (*qc_get_prepare_operation)(GWBUF* stmt);
void (*qc_get_field_info)(GWBUF* stmt, const QC_FIELD_INFO** infos, size_t* n_infos);
void (*qc_get_function_info)(GWBUF* stmt, const QC_FUNCTION_INFO** infos, size_t* n_infos);
/**
* Reports the operation of the statement.
*
* @param stmt A statement.
* @param type On return, the operation (one of @c qc_query_op_t), if
* @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_operation)(GWBUF* stmt, int32_t* op);
/**
* Reports the name of a created table.
*
* @param stmt A statement.
* @param name On return, the name of the created table, if
* @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_created_table_name)(GWBUF* stmt, char** name);
/**
* Reports whether a statement is a "DROP TABLE ..." statement.
*
* @param stmt A statement
* @param is_drop_table On return, non-zero if the statement is a DROP TABLE
* statement, if @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_is_drop_table_query)(GWBUF* stmt, int32_t* is_drop_table);
/**
* Returns all table names.
*
* @param stmt A statement.
* @param fullnames If non-zero, the full (i.e. qualified) names are returned.
* @param names On return, the names of the statement, if @c QC_RESULT_OK
* is returned.
* @param n_names On return, how many names were returned, if @c QC_RESULT_OK
* is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_table_names)(GWBUF* stmt, int32_t full_names, char*** names, int32_t *n_names);
/**
* The canonical version of a statement.
*
* @param stmt A statement.
* @param canonical On return, the canonical version of the statement, if @c QC_RESULT_OK
* is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_canonical)(GWBUF* stmt, char** canonical);
/**
* Reports whether the statement has a where clause.
*
* @param stmt A statement.
* @param has_clause On return, non-zero if the statement has a where clause, if
* @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_query_has_clause)(GWBUF* stmt, int32_t* has_clause);
/**
* Reports the database names.
*
* @param stmt A statement.
* @param names On return, the database names, if
* @c QC_RESULT_OK is returned.
* @param size On return, the number of names in @names, if
* @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_database_names)(GWBUF* stmt, char*** names, int32_t* size);
/**
* Reports the prepare name.
*
* @param stmt A statement.
* @param name On return, the name of a prepare statement, if
* @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_prepare_name)(GWBUF* stmt, char** name);
/**
* Reports the prepare operation.
*
* @param stmt A statement.
* @param name On return, the operation (one of @c qc_query_op_t) of a prepare
* statement, if @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_prepare_operation)(GWBUF* stmt, int32_t* op);
/**
* Reports field information.
*
* @param stmt A statement.
* @param infos On return, array of field infos, if @c QC_RESULT_OK is returned.
* @param n_infos On return, the size of @c infos, if @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_field_info)(GWBUF* stmt, const QC_FIELD_INFO** infos, uint32_t* n_infos);
/**
* The canonical version of a statement.
*
* @param stmt A statement.
* @param infos On return, array of function infos, if @c QC_RESULT_OK is returned.
* @param n_infos On return, the size of @c infos, if @c QC_RESULT_OK is returned.
*
* @return QC_RESULT_OK, if the parsing was not aborted due to resource
* exhaustion or equivalent.
*/
int32_t (*qc_get_function_info)(GWBUF* stmt, const QC_FUNCTION_INFO** infos, uint32_t* n_infos);
} QUERY_CLASSIFIER;
/**