source: vendor/current/lib/tdb/test/external-agent.h

#ifndef TDB_TEST_EXTERNAL_AGENT_H
#define TDB_TEST_EXTERNAL_AGENT_H

/* For locking tests, we need a different process to try things at
 * various times. */
enum operation {
        OPEN,
        OPEN_WITH_CLEAR_IF_FIRST,
        TRANSACTION_START,
        FETCH,
        STORE,
        TRANSACTION_COMMIT,
        CHECK,
        NEEDS_RECOVERY,
        CLOSE,
        PING,
        UNMAP,
};

/* Do this before doing any tdb stuff.  Return handle, or -1. */
struct agent *prepare_external_agent(void);
void shutdown_agent(struct agent *agent);

enum agent_return {
        SUCCESS,
        WOULD_HAVE_BLOCKED,
        AGENT_DIED,
        FAILED, /* For fetch, or NEEDS_RECOVERY */
        OTHER_FAILURE,
};

/* Ask the external agent to try to do an operation.
 * name == tdb name for OPEN/OPEN_WITH_CLEAR_IF_FIRST,
 * record name for FETCH/STORE (store stores name as data too)
 */
enum agent_return external_agent_operation(struct agent *handle,
                                           enum operation op,
                                           const char *name);

/* Mapping enum -> string. */
const char *agent_return_name(enum agent_return ret);
const char *operation_name(enum operation op);

#endif /* TDB_TEST_EXTERNAL_AGENT_H */