/* 
   Unix SMB/CIFS implementation.

   generalised event loop handling

   Internal structs

   Copyright (C) Stefan Metzmacher 2005-2009

     ** NOTE! The following LGPL license applies to the tevent
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/

struct tevent_req {
	/**
	 * @brief What to do on completion
	 *
	 * This is used for the user of an async request, fn is called when
	 * the request completes, either successfully or with an error.
	 */
	struct {
		/**
		 * @brief Completion function
		 * Completion function, to be filled by the API user
		 */
		tevent_req_fn fn;
		/**
		 * @brief Private data for the completion function
		 */
		void *private_data;
	} async;

	/**
	 * @brief Private state pointer for the actual implementation
	 *
	 * The implementation doing the work for the async request needs to
	 * keep around current data like for example a fd event. The user of
	 * an async request should not touch this.
	 */
	void *data;

	/**
	 * @brief A function to overwrite the default print function
	 *
	 * The implementation doing the work may want to implement a
	 * custom function to print the text representation of the async
	 * request.
	 */
	tevent_req_print_fn private_print;

	/**
	 * @brief Internal state of the request
	 *
	 * Callers should only access this via functions and never directly.
	 */
	struct {
		/**
		 * @brief The talloc type of the data pointer
		 *
		 * This is filled by the tevent_req_create() macro.
		 *
		 * This for debugging only.
		 */
		const char *private_type;

		/**
		 * @brief The location where the request was created
		 *
		 * This uses the __location__ macro via the tevent_req_create()
		 * macro.
		 *
		 * This for debugging only.
		 */
		const char *create_location;

		/**
		 * @brief The location where the request was finished
		 *
		 * This uses the __location__ macro via the tevent_req_done(),
		 * tevent_req_error() or tevent_req_nomem() macro.
		 *
		 * This for debugging only.
		 */
		const char *finish_location;

		/**
		 * @brief The external state - will be queried by the caller
		 *
		 * While the async request is being processed, state will remain in
		 * TEVENT_REQ_IN_PROGRESS. A request is finished if
		 * req->state>=TEVENT_REQ_DONE.
		 */
		enum tevent_req_state state;

		/**
		 * @brief status code when finished
		 *
		 * This status can be queried in the async completion function. It
		 * will be set to 0 when everything went fine.
		 */
		uint64_t error;

		/**
		 * @brief the immediate event used by tevent_req_post
		 *
		 */
		struct tevent_immediate *trigger;

		/**
		 * @brief the timer event if tevent_req_set_timeout was used
		 *
		 */
		struct tevent_timer *timer;
	} internal;
};

struct tevent_ops {
	/* conntext init */
	int (*context_init)(struct tevent_context *ev);

	/* fd_event functions */
	struct tevent_fd *(*add_fd)(struct tevent_context *ev,
				    TALLOC_CTX *mem_ctx,
				    int fd, uint16_t flags,
				    tevent_fd_handler_t handler,
				    void *private_data,
				    const char *handler_name,
				    const char *location);
	void (*set_fd_close_fn)(struct tevent_fd *fde,
				tevent_fd_close_fn_t close_fn);
	uint16_t (*get_fd_flags)(struct tevent_fd *fde);
	void (*set_fd_flags)(struct tevent_fd *fde, uint16_t flags);

	/* timed_event functions */
	struct tevent_timer *(*add_timer)(struct tevent_context *ev,
					  TALLOC_CTX *mem_ctx,
					  struct timeval next_event,
					  tevent_timer_handler_t handler,
					  void *private_data,
					  const char *handler_name,
					  const char *location);

	/* immediate event functions */
	void (*schedule_immediate)(struct tevent_immediate *im,
				   struct tevent_context *ev,
				   tevent_immediate_handler_t handler,
				   void *private_data,
				   const char *handler_name,
				   const char *location);

	/* signal functions */
	struct tevent_signal *(*add_signal)(struct tevent_context *ev,
					    TALLOC_CTX *mem_ctx,
					    int signum, int sa_flags,
					    tevent_signal_handler_t handler,
					    void *private_data,
					    const char *handler_name,
					    const char *location);

	/* loop functions */
	int (*loop_once)(struct tevent_context *ev, const char *location);
	int (*loop_wait)(struct tevent_context *ev, const char *location);
};

struct tevent_fd {
	struct tevent_fd *prev, *next;
	struct tevent_context *event_ctx;
	int fd;
	uint16_t flags; /* see TEVENT_FD_* flags */
	tevent_fd_handler_t handler;
	tevent_fd_close_fn_t close_fn;
	/* this is private for the specific handler */
	void *private_data;
	/* this is for debugging only! */
	const char *handler_name;
	const char *location;
	/* this is private for the events_ops implementation */
	uint16_t additional_flags;
	void *additional_data;
};

struct tevent_timer {
	struct tevent_timer *prev, *next;
	struct tevent_context *event_ctx;
	struct timeval next_event;
	tevent_timer_handler_t handler;
	/* this is private for the specific handler */
	void *private_data;
	/* this is for debugging only! */
	const char *handler_name;
	const char *location;
	/* this is private for the events_ops implementation */
	void *additional_data;
};

struct tevent_immediate {
	struct tevent_immediate *prev, *next;
	struct tevent_context *event_ctx;
	tevent_immediate_handler_t handler;
	/* this is private for the specific handler */
	void *private_data;
	/* this is for debugging only! */
	const char *handler_name;
	const char *create_location;
	const char *schedule_location;
	/* this is private for the events_ops implementation */
	void (*cancel_fn)(struct tevent_immediate *im);
	void *additional_data;
};

struct tevent_signal {
	struct tevent_signal *prev, *next;
	struct tevent_context *event_ctx;
	int signum;
	int sa_flags;
	tevent_signal_handler_t handler;
	/* this is private for the specific handler */
	void *private_data;
	/* this is for debugging only! */
	const char *handler_name;
	const char *location;
	/* this is private for the events_ops implementation */
	void *additional_data;
};

struct tevent_debug_ops {
	void (*debug)(void *context, enum tevent_debug_level level,
		      const char *fmt, va_list ap) PRINTF_ATTRIBUTE(3,0);
	void *context;
};

void tevent_debug(struct tevent_context *ev, enum tevent_debug_level level,
		  const char *fmt, ...) PRINTF_ATTRIBUTE(3,4);

struct tevent_context {
	/* the specific events implementation */
	const struct tevent_ops *ops;

	/* list of fd events - used by common code */
	struct tevent_fd *fd_events;

	/* list of timed events - used by common code */
	struct tevent_timer *timer_events;

	/* list of immediate events - used by common code */
	struct tevent_immediate *immediate_events;

	/* list of signal events - used by common code */
	struct tevent_signal *signal_events;

	/* this is private for the events_ops implementation */
	void *additional_data;

	/* pipe hack used with signal handlers */
	struct tevent_fd *pipe_fde;

	/* debugging operations */
	struct tevent_debug_ops debug_ops;

	/* info about the nesting status */
	struct {
		bool allowed;
		uint32_t level;
		tevent_nesting_hook hook_fn;
		void *hook_private;
	} nesting;
};


bool tevent_register_backend(const char *name, const struct tevent_ops *ops);

int tevent_common_context_destructor(struct tevent_context *ev);
int tevent_common_loop_wait(struct tevent_context *ev,
			    const char *location);

int tevent_common_fd_destructor(struct tevent_fd *fde);
struct tevent_fd *tevent_common_add_fd(struct tevent_context *ev,
				       TALLOC_CTX *mem_ctx,
				       int fd,
				       uint16_t flags,
				       tevent_fd_handler_t handler,
				       void *private_data,
				       const char *handler_name,
				       const char *location);
void tevent_common_fd_set_close_fn(struct tevent_fd *fde,
				   tevent_fd_close_fn_t close_fn);
uint16_t tevent_common_fd_get_flags(struct tevent_fd *fde);
void tevent_common_fd_set_flags(struct tevent_fd *fde, uint16_t flags);

struct tevent_timer *tevent_common_add_timer(struct tevent_context *ev,
					     TALLOC_CTX *mem_ctx,
					     struct timeval next_event,
					     tevent_timer_handler_t handler,
					     void *private_data,
					     const char *handler_name,
					     const char *location);
struct timeval tevent_common_loop_timer_delay(struct tevent_context *);

void tevent_common_schedule_immediate(struct tevent_immediate *im,
				      struct tevent_context *ev,
				      tevent_immediate_handler_t handler,
				      void *private_data,
				      const char *handler_name,
				      const char *location);
bool tevent_common_loop_immediate(struct tevent_context *ev);

struct tevent_signal *tevent_common_add_signal(struct tevent_context *ev,
					       TALLOC_CTX *mem_ctx,
					       int signum,
					       int sa_flags,
					       tevent_signal_handler_t handler,
					       void *private_data,
					       const char *handler_name,
					       const char *location);
int tevent_common_check_signal(struct tevent_context *ev);

bool tevent_standard_init(void);
bool tevent_select_init(void);
#ifdef HAVE_EPOLL
bool tevent_epoll_init(void);
#endif