src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h

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#ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H
#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H

#include <ares.h>

#include "src/core/lib/iomgr/exec_ctx.h"
#include "src/core/lib/iomgr/pollset_set.h"

typedef struct grpc_ares_ev_driver grpc_ares_ev_driver;

/* Start \a ev_driver. It will keep working until all IO on its ares_channel is
   done, or grpc_ares_ev_driver_destroy() is called. It may notify the callbacks
   bound to its ares_channel when necessary. */
void grpc_ares_ev_driver_start(grpc_exec_ctx *exec_ctx,
                               grpc_ares_ev_driver *ev_driver);

/* Returns the ares_channel owned by \a ev_driver. To bind a c-ares query to
   \a ev_driver, use the ares_channel owned by \a ev_driver as the arg of the
   query. */
ares_channel *grpc_ares_ev_driver_get_channel(grpc_ares_ev_driver *ev_driver);

/* Creates a new grpc_ares_ev_driver. Returns GRPC_ERROR_NONE if \a ev_driver is
   created successfully. */
grpc_error *grpc_ares_ev_driver_create(grpc_ares_ev_driver **ev_driver,
                                       grpc_pollset_set *pollset_set);

/* Destroys \a ev_driver asynchronously. Pending lookups made on \a ev_driver
   will be cancelled and their on_done callbacks will be invoked with a status
   of ARES_ECANCELLED. */
void grpc_ares_ev_driver_destroy(grpc_ares_ev_driver *ev_driver);

#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H */