ccan/tevent/tevent_immediate.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    common events code for immediate events
   5
   6    Copyright (C) Stefan Metzmacher 2009
   7
   8      ** NOTE! The following LGPL license applies to the tevent
   9      ** library. This does NOT imply that all of Samba is released
  10      ** under the LGPL
  11
  12    This library is free software; you can redistribute it and/or
  13    modify it under the terms of the GNU Lesser General Public
  14    License as published by the Free Software Foundation; either
  15    version 3 of the License, or (at your option) any later version.
  16
  17    This library is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20    Lesser General Public License for more details.
  21
  22    You should have received a copy of the GNU Lesser General Public
  23    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  24 */
  25
  26 #include <ccan/tevent/tevent.h>
  27 #include <ccan/tevent/tevent_internal.h>
  28 #include <ccan/tevent/tevent_util.h>
  29
  30 static void tevent_common_immediate_cancel(struct tevent_immediate *im)
  31 {
  32         if (!im->event_ctx) {
  33                 return;
  34         }
  35
  36         tevent_debug(im->event_ctx, TEVENT_DEBUG_TRACE,
  37                      "Cancel immediate event %p \"%s\"\n",
  38                      im, im->handler_name);
  39
  40         /* let the backend free im->additional_data */
  41         if (im->cancel_fn) {
  42                 im->cancel_fn(im);
  43         }
  44
  45         DLIST_REMOVE(im->event_ctx->immediate_events, im);
  46         im->event_ctx           = NULL;
  47         im->handler             = NULL;
  48         im->private_data        = NULL;
  49         im->handler_name        = NULL;
  50         im->schedule_location   = NULL;
  51         im->cancel_fn           = NULL;
  52         im->additional_data     = NULL;
  53
  54         talloc_set_destructor(im, NULL);
  55 }
  56
  57 /*
  58   destroy an immediate event
  59 */
  60 static int tevent_common_immediate_destructor(struct tevent_immediate *im)
  61 {
  62         tevent_common_immediate_cancel(im);
  63         return 0;
  64 }
  65
  66 /*
  67  * schedule an immediate event on
  68  */
  69 void tevent_common_schedule_immediate(struct tevent_immediate *im,
  70                                       struct tevent_context *ev,
  71                                       tevent_immediate_handler_t handler,
  72                                       void *private_data,
  73                                       const char *handler_name,
  74                                       const char *location)
  75 {
  76         tevent_common_immediate_cancel(im);
  77
  78         if (!handler) {
  79                 return;
  80         }
  81
  82         im->event_ctx           = ev;
  83         im->handler             = handler;
  84         im->private_data        = private_data;
  85         im->handler_name        = handler_name;
  86         im->schedule_location   = location;
  87         im->cancel_fn           = NULL;
  88         im->additional_data     = NULL;
  89
  90         DLIST_ADD_END(ev->immediate_events, im, struct tevent_immediate *);
  91         talloc_set_destructor(im, tevent_common_immediate_destructor);
  92
  93         tevent_debug(ev, TEVENT_DEBUG_TRACE,
  94                      "Schedule immediate event \"%s\": %p\n",
  95                      handler_name, im);
  96 }
  97
  98 /*
  99   trigger the first immediate event and return true
 100   if no event was triggered return false
 101 */
 102 bool tevent_common_loop_immediate(struct tevent_context *ev)
 103 {
 104         struct tevent_immediate *im = ev->immediate_events;
 105         tevent_immediate_handler_t handler;
 106         void *private_data;
 107
 108         if (!im) {
 109                 return false;
 110         }
 111
 112         tevent_debug(ev, TEVENT_DEBUG_TRACE,
 113                      "Run immediate event \"%s\": %p\n",
 114                      im->handler_name, im);
 115
 116         /*
 117          * remember the handler and then clear the event
 118          * the handler might reschedule the event
 119          */
 120         handler = im->handler;
 121         private_data = im->private_data;
 122
 123         DLIST_REMOVE(im->event_ctx->immediate_events, im);
 124         im->event_ctx           = NULL;
 125         im->handler             = NULL;
 126         im->private_data        = NULL;
 127         im->handler_name        = NULL;
 128         im->schedule_location   = NULL;
 129         im->cancel_fn           = NULL;
 130         im->additional_data     = NULL;
 131
 132         talloc_set_destructor(im, NULL);
 133
 134         handler(ev, im, private_data);
 135
 136         return true;
 137 }
 138