lib/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 "replace.h"
  27 #include "tevent.h"
  28 #include "tevent_internal.h"
  29 #include "tevent_util.h"
  30
  31 static void tevent_common_immediate_cancel(struct tevent_immediate *im)
  32 {
  33         if (!im->event_ctx) {
  34                 return;
  35         }
  36
  37         tevent_debug(im->event_ctx, TEVENT_DEBUG_TRACE,
  38                      "Cancel immediate event %p \"%s\"\n",
  39                      im, im->handler_name);
  40
  41         /* let the backend free im->additional_data */
  42         if (im->cancel_fn) {
  43                 im->cancel_fn(im);
  44         }
  45
  46         DLIST_REMOVE(im->event_ctx->immediate_events, im);
  47         im->event_ctx           = NULL;
  48         im->handler             = NULL;
  49         im->private_data        = NULL;
  50         im->handler_name        = NULL;
  51         im->schedule_location   = NULL;
  52         im->cancel_fn           = NULL;
  53         im->additional_data     = NULL;
  54
  55         talloc_set_destructor(im, NULL);
  56 }
  57
  58 /*
  59   destroy an immediate event
  60 */
  61 static int tevent_common_immediate_destructor(struct tevent_immediate *im)
  62 {
  63         tevent_common_immediate_cancel(im);
  64         return 0;
  65 }
  66
  67 /*
  68  * schedule an immediate event on
  69  */
  70 void tevent_common_schedule_immediate(struct tevent_immediate *im,
  71                                       struct tevent_context *ev,
  72                                       tevent_immediate_handler_t handler,
  73                                       void *private_data,
  74                                       const char *handler_name,
  75                                       const char *location)
  76 {
  77         tevent_common_immediate_cancel(im);
  78
  79         if (!handler) {
  80                 return;
  81         }
  82
  83         im->event_ctx           = ev;
  84         im->handler             = handler;
  85         im->private_data        = private_data;
  86         im->handler_name        = handler_name;
  87         im->schedule_location   = location;
  88         im->cancel_fn           = NULL;
  89         im->additional_data     = NULL;
  90
  91         DLIST_ADD_END(ev->immediate_events, im);
  92         talloc_set_destructor(im, tevent_common_immediate_destructor);
  93
  94         tevent_debug(ev, TEVENT_DEBUG_TRACE,
  95                      "Schedule immediate event \"%s\": %p\n",
  96                      handler_name, im);
  97 }
  98
  99 /*
 100   trigger the first immediate event and return true
 101   if no event was triggered return false
 102 */
 103 bool tevent_common_loop_immediate(struct tevent_context *ev)
 104 {
 105         struct tevent_immediate *im = ev->immediate_events;
 106         tevent_immediate_handler_t handler;
 107         void *private_data;
 108
 109         if (!im) {
 110                 return false;
 111         }
 112
 113         tevent_debug(ev, TEVENT_DEBUG_TRACE,
 114                      "Run immediate event \"%s\": %p\n",
 115                      im->handler_name, im);
 116
 117         /*
 118          * remember the handler and then clear the event
 119          * the handler might reschedule the event
 120          */
 121         handler = im->handler;
 122         private_data = im->private_data;
 123
 124         DLIST_REMOVE(im->event_ctx->immediate_events, im);
 125         im->event_ctx           = NULL;
 126         im->handler             = NULL;
 127         im->private_data        = NULL;
 128         im->handler_name        = NULL;
 129         im->schedule_location   = NULL;
 130         im->cancel_fn           = NULL;
 131         im->additional_data     = NULL;
 132
 133         talloc_set_destructor(im, NULL);
 134
 135         handler(ev, im, private_data);
 136
 137         return true;
 138 }
 139