engine_activate.c

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/*
** Copyright (C) 2005 by Kevin L. Mitchell <klmitch@mit.edu>
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program 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 General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
**
** @(#)$Id: engine_activate.c,v 1.4 2005/12/18 00:15:10 klmitch Exp $
*/
#include "engines_int.h"

RCSTAG("@(#)$Id: engine_activate.c,v 1.4 2005/12/18 00:15:10 klmitch Exp $");

#define eng_link(ctx, engine, comp)                                           \
do {                                                                          \
  ev_ctx_t *_ctx = (ctx);                                                     \
  ev_engine_t *_eng = (engine);                                               \
  if (!_ctx->ec_ ## comp.el_last) { /* no items in list yet... */             \
    /* initialize the context list pointers... */                             \
    _ctx->ec_ ## comp.el_first = _ctx->ec_ ## comp.el_last = _eng;            \
    /* now initialize the engine list pointers...the cast is ugly, but        \
     * keeps us from having to specify the structure prefix, too              \
     */                                                                       \
    ((_ev_englink_t *)&_eng->eng_ ## comp)->el_next = 0;                      \
    ((_ev_englink_t *)&_eng->eng_ ## comp)->el_prev = 0;                      \
  } else { /* ok, link engine at end of list */                               \
    ev_engine_t *_last = _ctx->ec_ ## comp.el_last; /* save some typing */    \
    ((_ev_englink_t *)&_last->eng_ ## comp)->el_next = _eng; /* add to list */\
    ((_ev_englink_t *)&_eng->eng_ ## comp)->el_prev = _last; /* link engine */\
    ((_ev_englink_t *)&_eng->eng_ ## comp)->el_next = 0;                      \
    _ctx->ec_ ## comp.el_last = _eng; /* update last pointer */               \
  }                                                                           \
} while (0)

ev_err_t
engine_activate(ev_ctx_t *ctx, ev_engine_t *engine, ev_flags_t comps)
{
  ev_init(); /* make sure library is initialized... */

  /* mask components specifier... */
  comps &= EV_ENGINE_COMPMASK;

  if (!ec_verify(ctx) || !eng_verify(engine) ||
      !(engine->eng_runfl & EV_ENGINE_REGISTERED) ||
      (engine->eng_runfl & EV_ENGINE_RUNNING) || !comps)
    ev_return(EINVAL); /* sanity-check arguments */

  if (comps & EV_ENGINE_SOCKET) /* perform the links... */
    eng_link(ctx, engine, socket);
  if (comps & EV_ENGINE_SIGNAL)
    eng_link(ctx, engine, signal);
  if (comps & EV_ENGINE_TIMER)
    eng_link(ctx, engine, timer);

  /* Now set the run flags */
  eng_runfl_set(engine, comps | EV_ENGINE_RUNNING);

  ev_return(0); /* all done! */
}

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