presencestate.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2011-2012, Digium, Inc.
 *
 * David Vossel <dvossel@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Presence state management
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 381594 $")

#include "asterisk/_private.h"
#include "asterisk/utils.h"
#include "asterisk/lock.h"
#include "asterisk/linkedlists.h"
#include "asterisk/presencestate.h"
#include "asterisk/pbx.h"
#include "asterisk/app.h"
#include "asterisk/event.h"

/*! \brief Device state strings for printing */
static const struct {
   const char *string;
   enum ast_presence_state state;

} state2string[] = {
   { "not_set", AST_PRESENCE_NOT_SET},
   { "unavailable", AST_PRESENCE_UNAVAILABLE },
   { "available", AST_PRESENCE_AVAILABLE},
   { "away", AST_PRESENCE_AWAY},
   { "xa", AST_PRESENCE_XA},
   { "chat", AST_PRESENCE_CHAT},
   { "dnd", AST_PRESENCE_DND},
};

/*! \brief Flag for the queue */
static ast_cond_t change_pending;

struct state_change {
   AST_LIST_ENTRY(state_change) list;
   char provider[1];
};

/*! \brief  A presence state provider */
struct presence_state_provider {
   char label[40];
   ast_presence_state_prov_cb_type callback;
   AST_RWLIST_ENTRY(presence_state_provider) list;
};

/*! \brief A list of providers */
static AST_RWLIST_HEAD_STATIC(presence_state_providers, presence_state_provider);

/*! \brief The state change queue. State changes are queued
   for processing by a separate thread */
static AST_LIST_HEAD_STATIC(state_changes, state_change);

/*! \brief The presence state change notification thread */
static pthread_t change_thread = AST_PTHREADT_NULL;

const char *ast_presence_state2str(enum ast_presence_state state)
{
   int i;
   for (i = 0; i < ARRAY_LEN(state2string); i++) {
      if (state == state2string[i].state) {
         return state2string[i].string;
      }
   }
   return "";
}

enum ast_presence_state ast_presence_state_val(const char *val)
{
   int i;
   for (i = 0; i < ARRAY_LEN(state2string); i++) {
      if (!strcasecmp(val, state2string[i].string)) {
         return state2string[i].state;
      }
   }
   return AST_PRESENCE_INVALID;
}

static enum ast_presence_state presence_state_cached(const char *presence_provider, char **subtype, char **message)
{
   enum ast_presence_state res = AST_PRESENCE_INVALID;
   struct ast_event *event;
   const char *_subtype;
   const char *_message;

   event = ast_event_get_cached(AST_EVENT_PRESENCE_STATE,
      AST_EVENT_IE_PRESENCE_PROVIDER, AST_EVENT_IE_PLTYPE_STR, presence_provider,
      AST_EVENT_IE_END);

   if (!event) {
      return res;
   }

   res = ast_event_get_ie_uint(event, AST_EVENT_IE_PRESENCE_STATE);
   _subtype = ast_event_get_ie_str(event, AST_EVENT_IE_PRESENCE_SUBTYPE);
   _message = ast_event_get_ie_str(event, AST_EVENT_IE_PRESENCE_MESSAGE);

   *subtype = !ast_strlen_zero(_subtype) ? ast_strdup(_subtype) : NULL;
   *message = !ast_strlen_zero(_message) ? ast_strdup(_message) : NULL;
   ast_event_destroy(event);

   return res;
}

static enum ast_presence_state ast_presence_state_helper(const char *presence_provider, char **subtype, char **message, int check_cache)
{
   struct presence_state_provider *provider;
   char *address;
   char *label = ast_strdupa(presence_provider);
   int res = AST_PRESENCE_INVALID;

   if (check_cache) {
      res = presence_state_cached(presence_provider, subtype, message);
      if (res != AST_PRESENCE_INVALID) {
         return res;
      }
   }

   if ((address = strchr(label, ':'))) {
      *address = '\0';
      address++;
   } else {
      ast_log(LOG_WARNING, "No label found for presence state provider: %s\n", presence_provider);
      return res;
   }

   AST_RWLIST_RDLOCK(&presence_state_providers);
   AST_RWLIST_TRAVERSE(&presence_state_providers, provider, list) {
      ast_debug(5, "Checking provider %s with %s\n", provider->label, label);

      if (!strcasecmp(provider->label, label)) {
         res = provider->callback(address, subtype, message);
         break;
      }
   }
   AST_RWLIST_UNLOCK(&presence_state_providers);

   if (!provider) {
      ast_log(LOG_WARNING, "No provider found for label %s\n", label);
   }

   return res;
}

enum ast_presence_state ast_presence_state(const char *presence_provider, char **subtype, char **message)
{
   return ast_presence_state_helper(presence_provider, subtype, message, 1);
}

enum ast_presence_state ast_presence_state_nocache(const char *presence_provider, char **subtype, char **message)
{
   return ast_presence_state_helper(presence_provider, subtype, message, 0);
}

int ast_presence_state_prov_add(const char *label, ast_presence_state_prov_cb_type callback)
{
   struct presence_state_provider *provider;

   if (!callback || !(provider = ast_calloc(1, sizeof(*provider)))) {
      return -1;
   }

   provider->callback = callback;
   ast_copy_string(provider->label, label, sizeof(provider->label));

   AST_RWLIST_WRLOCK(&presence_state_providers);
   AST_RWLIST_INSERT_HEAD(&presence_state_providers, provider, list);
   AST_RWLIST_UNLOCK(&presence_state_providers);

   return 0;
}
int ast_presence_state_prov_del(const char *label)
{
   struct presence_state_provider *provider;
   int res = -1;

   AST_RWLIST_WRLOCK(&presence_state_providers);
   AST_RWLIST_TRAVERSE_SAFE_BEGIN(&presence_state_providers, provider, list) {
      if (!strcasecmp(provider->label, label)) {
         AST_RWLIST_REMOVE_CURRENT(list);
         ast_free(provider);
         res = 0;
         break;
      }
   }
   AST_RWLIST_TRAVERSE_SAFE_END;
   AST_RWLIST_UNLOCK(&presence_state_providers);

   return res;
}

static void presence_state_event(const char *provider,
      enum ast_presence_state state,
      const char *subtype,
      const char *message)
{
   struct ast_event *event;

   if (!(event = ast_event_new(AST_EVENT_PRESENCE_STATE,
         AST_EVENT_IE_PRESENCE_PROVIDER, AST_EVENT_IE_PLTYPE_STR, provider,
         AST_EVENT_IE_PRESENCE_STATE, AST_EVENT_IE_PLTYPE_UINT, state,
         AST_EVENT_IE_PRESENCE_SUBTYPE, AST_EVENT_IE_PLTYPE_STR, S_OR(subtype, ""),
         AST_EVENT_IE_PRESENCE_MESSAGE, AST_EVENT_IE_PLTYPE_STR, S_OR(message, ""),
         AST_EVENT_IE_END))) {
      return;
   }

   ast_event_queue_and_cache(event);
}

static void do_presence_state_change(const char *provider)
{
   char *subtype = NULL;
   char *message = NULL;
   enum ast_presence_state state;

   state = ast_presence_state_helper(provider, &subtype, &message, 0);

   if (state < 0) {
      return;
   }

   presence_state_event(provider, state, subtype, message);
   ast_free(subtype);
   ast_free(message);
}

int ast_presence_state_changed_literal(enum ast_presence_state state,
      const char *subtype,
      const char *message,
      const char *presence_provider)
{
   struct state_change *change;

   if (state != AST_PRESENCE_NOT_SET) {
      presence_state_event(presence_provider, state, subtype, message);
   } else if ((change_thread == AST_PTHREADT_NULL) ||
      !(change = ast_calloc(1, sizeof(*change) + strlen(presence_provider)))) {
      do_presence_state_change(presence_provider);
   } else {
      strcpy(change->provider, presence_provider);
      AST_LIST_LOCK(&state_changes);
      AST_LIST_INSERT_TAIL(&state_changes, change, list);
      ast_cond_signal(&change_pending);
      AST_LIST_UNLOCK(&state_changes);
   }

   return 0;
}

int ast_presence_state_changed(enum ast_presence_state state,
      const char *subtype,
      const char *message,
      const char *fmt, ...)
{
   char buf[AST_MAX_EXTENSION];
   va_list ap;

   va_start(ap, fmt);
   vsnprintf(buf, sizeof(buf), fmt, ap);
   va_end(ap);

   return ast_presence_state_changed_literal(state, subtype, message, buf);
}

/*! \brief Go through the presence state change queue and update changes in the presence state thread */
static void *do_presence_changes(void *data)
{
   struct state_change *next, *current;

   for (;;) {
      /* This basically pops off any state change entries, resets the list back to NULL, unlocks, and processes each state change */
      AST_LIST_LOCK(&state_changes);
      if (AST_LIST_EMPTY(&state_changes))
         ast_cond_wait(&change_pending, &state_changes.lock);
      next = AST_LIST_FIRST(&state_changes);
      AST_LIST_HEAD_INIT_NOLOCK(&state_changes);
      AST_LIST_UNLOCK(&state_changes);

      /* Process each state change */
      while ((current = next)) {
         next = AST_LIST_NEXT(current, list);
         do_presence_state_change(current->provider);
         ast_free(current);
      }
   }

   return NULL;
}

int ast_presence_state_engine_init(void)
{
   ast_cond_init(&change_pending, NULL);
   if (ast_pthread_create_background(&change_thread, NULL, do_presence_changes, NULL) < 0) {
      ast_log(LOG_ERROR, "Unable to start presence state change thread.\n");
      return -1;
   }

   return 0;
}