kc3-lang/libevent/bufferevent-internal.h

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  Date : 2009-10-16T13:19:57
  

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• bufferevent-internal.h

• /*
   * Copyright (c) 2008-2009 Niels Provos and Nick Mathewson
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  #ifndef _BUFFEREVENT_INTERNAL_H_
  #define _BUFFEREVENT_INTERNAL_H_
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #include "event-config.h"
  #include "evutil.h"
  #include "defer-internal.h"
  #include "evthread-internal.h"
  #include "event2/thread.h"
  
  /** Parts of the bufferevent structure that are shared among all bufferevent
   * types, but not exposed in bufferevent_struct.h. */
  struct bufferevent_private {
  	/** The underlying bufferevent structure. */
  	struct bufferevent bev;
  
  	/** Evbuffer callback to enforce watermarks on input. */
  	struct evbuffer_cb_entry *read_watermarks_cb;
  
  	/** If set, read is suspended until evbuffer some. */
  	unsigned read_suspended : 1;
  	/** If set, we should free the lock when we free the bufferevent. */
  	unsigned own_lock : 1;
  
  	/** Flag: set if we have deferred callbacks and a read callback is
  	 * pending. */
  	unsigned readcb_pending : 1;
  	/** Flag: set if we have deferred callbacks and a write callback is
  	 * pending. */
  	unsigned writecb_pending : 1;
  	/** Flag: set if we are currently busy connecting. */
  	unsigned connecting : 1;
  	/** Set to the events pending if we have deferred callbacks and
  	 * an events callback is pending. */
  	short eventcb_pending;
  	/** Set to the current socket errno if we have deferred callbacks and
  	 * an events callback is pending. */
  	int errno_pending;
  	/** Used to implement deferred callbacks */
  	struct deferred_cb deferred;
  
  	/** The options this bufferevent was constructed with */
  	enum bufferevent_options options;
  
  	/** Current reference count for this bufferevent. */
  	int refcnt;
  
  	/** Lock for this bufferevent.  Shared by the inbuf and the outbuf.
  	 * If NULL, locking is disabled. */
  	void *lock;
  };
  
  /** Possible operations for a control callback. */
  enum bufferevent_ctrl_op {
  	BEV_CTRL_SET_FD,
  	BEV_CTRL_GET_FD,
  	BEV_CTRL_GET_UNDERLYING,
  };
  
  /** Possible data types for a control callback */
  union bufferevent_ctrl_data {
  	void *ptr;
  	evutil_socket_t fd;
  };
  
  /**
     Implementation table for a bufferevent: holds function pointers and other
     information to make the various bufferevent types work.
  */
  struct bufferevent_ops {
  	/** The name of the bufferevent's type. */
  	const char *type;
  	/** At what offset into the implementation type will we find a
  	    bufferevent structure?
  
  	    Example: if the type is implemented as
  	    struct bufferevent_x {
  	       int extra_data;
  	       struct bufferevent bev;
  	    }
  	    then mem_offset should be offsetof(struct bufferevent_x, bev)
  	*/
  	off_t mem_offset;
  
  	/** Enables one or more of EV_READ|EV_WRITE on a bufferevent.  Does
  	    not need to adjust the 'enabled' field.  Returns 0 on success, -1
  	    on failure.
  	 */
  	int (*enable)(struct bufferevent *, short);
  
  	/** Disables one or more of EV_READ|EV_WRITE on a bufferevent.  Does
  	    not need to adjust the 'enabled' field.  Returns 0 on success, -1
  	    on failure.
  	 */
  	int (*disable)(struct bufferevent *, short);
  
  	/** Free any storage and deallocate any extra data or structures used
  	    in this implementation.
  	 */
  	void (*destruct)(struct bufferevent *);
  
  	/** Called when the timeouts on the bufferevent have changed.*/
  	void (*adj_timeouts)(struct bufferevent *);
  
          /** Called to flush data. */
          int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode);
  
  	/** Called to access miscellaneous fields. */
  	int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *);
  };
  
  extern const struct bufferevent_ops bufferevent_ops_socket;
  extern const struct bufferevent_ops bufferevent_ops_filter;
  extern const struct bufferevent_ops bufferevent_ops_pair;
  
  /** Initialize the shared parts of a bufferevent. */
  int bufferevent_init_common(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options);
  
  /** For internal use: temporarily stop all reads on bufev, because its
   * read buffer is too full. */
  void bufferevent_wm_suspend_read(struct bufferevent *bufev);
  /** For internal use: temporarily stop all reads on bufev, because its
   * read buffer is too full. */
  void bufferevent_wm_unsuspend_read(struct bufferevent *bufev);
  
  /** Internal: Set up locking on a bufferevent.  If lock is set, use it.
   * Otherwise, use a new lock. */
  int bufferevent_enable_locking(struct bufferevent *bufev, void *lock);
  /** Internal: Increment the reference count on bufev. */
  void bufferevent_incref(struct bufferevent *bufev);
  /** Internal: Lock bufev and increase its reference count.
   * unlocking it otherwise. */
  void _bufferevent_incref_and_lock(struct bufferevent *bufev);
  /** Internal: Drop the reference count on bufev, freeing as necessary, and
   * unlocking it otherwise. */
  void _bufferevent_decref_and_unlock(struct bufferevent *bufev);
  
  /** Internal: If callbacks are deferred and we have a read callback, schedule
   * a readcb.  Otherwise just run the readcb. */
  void _bufferevent_run_readcb(struct bufferevent *bufev);
  /** Internal: If callbacks are deferred and we have a write callback, schedule
   * a writecb.  Otherwise just run the writecb. */
  void _bufferevent_run_writecb(struct bufferevent *bufev);
  /** Internal: If callbacks are deferred and we have an eventcb, schedule
   * it to run with events "what".  Otherwise just run the eventcb. */
  void _bufferevent_run_eventcb(struct bufferevent *bufev, short what);
  
  /** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in
   * which case add ev with no timeout. */
  int _bufferevent_add_event(struct event *ev, const struct timeval *tv);
  
  /* =========
   * These next functions implement timeouts for bufferevents that aren't doing
   * anything else with ev_read and ev_write, to handle timeouts.
   * ========= */
  /** Internal use: Set up the ev_read and ev_write callbacks so that
   * the other "generic_timeout" functions will work on it.  Call this from
   * the constructor function. */
  void _bufferevent_init_generic_timeout_cbs(struct bufferevent *bev);
  /** Internal use: Delete the ev_read and ev_write callbacks if they're pending.
   * Call this from the destructor function. */
  void _bufferevent_del_generic_timeout_cbs(struct bufferevent *bev);
  /** Internal use: Add or delete the generic timeout events as appropriate.
   * (If an event is enabled and a timeout is set, we add the event.  Otherwise
   * we delete it.)  Call this from anything that changes the timeout values,
   * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */
  void _bufferevent_generic_adj_timeouts(struct bufferevent *bev);
  
  /** Internal use: We have just successfully read data into an inbuf, so
   * reset the read timeout (if any). */
  #define BEV_RESET_GENERIC_READ_TIMEOUT(bev)				\
  	do {								\
  		if (evutil_timerisset(&(bev)->timeout_read))		\
  			event_add(&(bev)->ev_read, &(bev)->timeout_read); \
  	} while (0)
  /** Internal use: We have just successfully written data from an inbuf, so
   * reset the read timeout (if any). */
  #define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev)				\
  	do {								\
  		if (evutil_timerisset(&(bev)->timeout_write))		\
  			event_add(&(bev)->ev_write, &(bev)->timeout_write); \
  	} while (0)
  
  /** Internal: Given a bufferevent, return its corresponding
   * bufferevent_private. */
  #define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev)
  
  /** Internal: Grab the lock (if any) on a bufferevent */
  #define BEV_LOCK(b) do {						\
  		struct bufferevent_private *locking =  BEV_UPCAST(b);	\
  		if (locking->lock)					\
  			EVLOCK_LOCK(locking->lock, EVTHREAD_WRITE);	\
  	} while(0)
  
  /** Internal: Release the lock (if any) on a bufferevent */
  #define BEV_UNLOCK(b) do {						\
  		struct bufferevent_private *locking =  BEV_UPCAST(b);	\
  		if (locking->lock)					\
  			EVLOCK_UNLOCK(locking->lock, EVTHREAD_WRITE);	\
  	} while(0)
  
  #ifdef __cplusplus
  }
  #endif
  
  
  #endif /* _BUFFEREVENT_INTERNAL_H_ */
  

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