terom@21: #ifndef EVSQL_H
terom@21: #define EVSQL_H
terom@21: 
terom@21: /*
terom@21:  * An event-based (Postgre)SQL client API using libevent
terom@21:  */
terom@21: 
terom@21: // XXX: libpq
terom@21: #include <postgresql/libpq-fe.h>
terom@21: #include <event2/event.h>
terom@21: 
terom@21: /*
terom@21:  * The generic context handle
terom@21:  */
terom@21: struct evsql;
terom@21: 
terom@21: /*
terom@21:  * A query handle
terom@21:  */
terom@21: struct evsql_query;
terom@21: 
terom@21: /*
terom@23:  * Query parameter info.
terom@23:  *
terom@23:  * Use the EVSQL_PARAM_* macros to define the value of list
terom@23:  */
terom@21: struct evsql_query_params {
terom@23:     // nonzero to get results in binary format
terom@23:     int result_binary;
terom@23:     
terom@23:     // the list of parameters, terminated by { 0, 0 }
terom@23:     struct evsql_query_param {
terom@23:         // the textual or binary value for this parameter
terom@23:         char *value;
terom@23: 
terom@23:         // the explicit length of the parameter if it's binary. Must be non-zero for NULL values.
terom@23:         int length;
terom@23:     } list[];
terom@23: };
terom@23: 
terom@23: // macros for defining evsql_query_params
terom@23: #define EVSQL_PARAM_NULL                    { NULL, 1 }
terom@23: #define EVSQL_PARAM_TEXT(value)             { value, 0 }
terom@23: #define EVSQL_PARAM_BINARY(value, length)   { value, length }
terom@21: 
terom@21: /*
terom@21:  * Result type
terom@21:  */
terom@21: struct evsql_result_info {
terom@21:     struct evsql *evsql;
terom@21:     
terom@21:     int error;
terom@21: 
terom@21:     union {
terom@21:         // XXX: libpq
terom@21:         PGresult *pq;
terom@21: 
terom@21:     } result;
terom@21: };
terom@21: 
terom@21: /*
terom@21:  * Callback for handling query-level errors.
terom@21:  *
terom@21:  * The query has completed, either succesfully or unsuccesfully (look at info.error).
terom@21:  * info.result contains the result à la the evsql's type.
terom@21:  */
terom@21: typedef void (*evsql_query_cb)(struct evsql_result_info info, void *arg);
terom@21: 
terom@21: /*
terom@21:  * Callback for handling connection-level errors.
terom@21:  *
terom@21:  * The SQL context/connection suffered an error. It is not valid anymore, and may not be used.
terom@21:  */
terom@21: typedef void (*evsql_error_cb)(struct evsql *evsql, void *arg);
terom@21: 
terom@21: /*
terom@21:  * Create a new PostgreSQL/libpq(evpq) -based evsql using the given conninfo.
terom@21:  */
terom@21: struct evsql *evsql_new_pq (struct event_base *ev_base, const char *pq_conninfo, evsql_error_cb error_fn, void *cb_arg);
terom@21: 
terom@21: /*
terom@21:  * Queue the given query for execution.
terom@21:  */
terom@21: struct evsql_query *evsql_query (struct evsql *evsql, const char *command, evsql_query_cb query_fn, void *cb_arg);
terom@21: 
terom@21: /*
terom@23:  * Same, but uses the SQL-level support for binding parameters.
terom@23:  */
terom@23: struct evsql_query *evsql_query_params (struct evsql *evsql, const char *command, struct evsql_query_params params, evsql_query_cb query_fn, void *cb_arg);
terom@23: 
terom@23: /*
terom@21:  * Close a connection. Callbacks for waiting queries will not be run.
terom@21:  *
terom@21:  * XXX: not implemented yet.
terom@21:  */
terom@21: void evsql_close (struct evsql *evsql);
terom@21: 
terom@21: #endif /* EVSQL_H */