terom@12: #ifndef EVPQ_H
terom@12: #define EVPQ_H
terom@12: 
terom@12: /*
terom@12:  * Convenience functions for using libpq (the PostgreSQL client library) with libevent.
terom@12:  */
terom@12: 
terom@12: #include <event2/event.h>
terom@12: #include <postgresql/libpq-fe.h>
terom@12: 
terom@12: /*
terom@12:  * Our PGconn context wrapper.
terom@12:  */
terom@12: struct evpq_conn;
terom@12: 
terom@12: /*
terom@12:  * Callback functions used
terom@12:  */
terom@12: struct evpq_callback_info {
terom@12:     /*
terom@12:      * This evpq_conn has connected succesfully \o/
terom@12:      */
terom@12:     void (*fn_connected)(struct evpq_conn *conn, void *arg);
terom@12: 
terom@12:     /*
terom@12:      * Got a result.
terom@12:      */
terom@12:     void (*fn_result)(struct evpq_conn *conn, PGresult *result, void *arg);
terom@12: 
terom@12:     /*
terom@12:      * No more results for the query
terom@12:      */
terom@12:     void (*fn_done)(struct evpq_conn *conn, void *arg);
terom@12:     
terom@12:     /*
terom@12:      * Something caused this evpq_conn to fail :(
terom@12:      *
terom@12:      * XXX: add a `what` arg?
terom@12:      */
terom@12:     void (*fn_failure)(struct evpq_conn *conn, void *arg);
terom@12: 
terom@12:     /*
terom@12:      * Arg to pass through to all callbacks.
terom@12:      */
terom@12:     void *cb_arg;
terom@12: };
terom@12: 
terom@12: /*
terom@12:  * evpq_conn states
terom@12:  */
terom@12: enum evpq_state {
terom@12:     EVPQ_INIT,
terom@12: 
terom@12:     EVPQ_CONNECT,
terom@12:     EVPQ_CONNECTED,
terom@12: 
terom@12:     EVPQ_QUERY,
terom@12: 
terom@12:     EVPQ_FAILURE,
terom@12: };
terom@12: 
terom@12: /*
terom@12:  * Create a new evpq connection.
terom@12:  *
terom@12:  * This corresponds directly to PQconnectStart, and handles all the libevent setup/polling needed.
terom@12:  *
terom@12:  * The connection will initially be in the EVPQ_CONNECT state, and will then either callback via fn_connected
terom@12:  * (EVPQ_CONNECTED) or fn_failure (EVPQ_FAILURE).
terom@12:  *
terom@12:  * cb_info contains the callback functions (and the user argument) to use.
terom@12:  */
terom@12: struct evpq_conn *evpq_connect (struct event_base *ev_base, const char *conninfo, const struct evpq_callback_info cb_info);
terom@12: 
terom@12: /*
terom@12:  * Execute a query.
terom@12:  *
terom@12:  * This corresponds directly to PQsendQuery. This evpq must be in the EVPQ_CONNECTED state, so you must wait after
terom@12:  * calling evpq_connect, and you may not run two queries at the same time.
terom@12:  *
terom@12:  * The query will result in a series of fn_result (EVPQ_RESULT) calls (if multiple queries in the query string),
terom@12:  * followed by a fn_done (EVPQ_CONNECTED).
terom@12:  */
terom@12: int evpq_query (struct evpq_conn *conn, const char *command);
terom@12: 
terom@12: /*
terom@12:  * Get the actual PGconn.
terom@12:  *
terom@12:  * This can safely be used to access all of the normal PQ functions.
terom@12:  */
terom@12: const PGconn *evpq_pgconn (struct evpq_conn *conn);
terom@12: 
terom@12: // convenience wrappers
terom@12: #define evpq_error_message(conn) PQerrorMessage(evpq_pgconn(conn))
terom@12: 
terom@12: 
terom@12: #endif /* EVPQ_H */