dbus-watch.c

/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-watch.c DBusWatch implementation
 *
 * Copyright (C) 2002, 2003  Red Hat Inc.
 *
 * SPDX-License-Identifier: AFL-2.1 OR GPL-2.0-or-later
 *
 * Licensed under the Academic Free License version 2.1
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */
 
#include <config.h>
#include "dbus-internals.h"
#include "dbus-watch.h"
#include "dbus-list.h"
 
struct DBusWatch
{
  int refcount;                        
  DBusPollable fd;                     
  unsigned int flags;                  
  DBusWatchHandler handler;                    
  void *handler_data;                          
  DBusFreeFunction free_handler_data_function; 
  void *data;                          
  DBusFreeFunction free_data_function; 
  unsigned int enabled : 1;            
  unsigned int oom_last_time : 1;      
};
 
dbus_bool_t
_dbus_watch_get_enabled (DBusWatch *watch)
{
  return watch->enabled;
}
 
dbus_bool_t
_dbus_watch_get_oom_last_time (DBusWatch *watch)
{
  return watch->oom_last_time;
}
 
void
_dbus_watch_set_oom_last_time (DBusWatch   *watch,
                               dbus_bool_t  oom)
{
  watch->oom_last_time = oom;
}
 
DBusWatch*
_dbus_watch_new (DBusPollable      fd,
                 unsigned int      flags,
                 dbus_bool_t       enabled,
                 DBusWatchHandler  handler,
                 void             *data,
                 DBusFreeFunction  free_data_function)
{
  DBusWatch *watch;
 
#define VALID_WATCH_FLAGS (DBUS_WATCH_WRITABLE | DBUS_WATCH_READABLE)
  
  _dbus_assert ((flags & VALID_WATCH_FLAGS) == flags);
  
  watch = dbus_new0 (DBusWatch, 1);
  if (watch == NULL)
    return NULL;
  
  watch->refcount = 1;
  watch->fd = fd;
  watch->flags = flags;
  watch->enabled = enabled;
 
  watch->handler = handler;
  watch->handler_data = data;
  watch->free_handler_data_function = free_data_function;
  
  return watch;
}
 
DBusWatch *
_dbus_watch_ref (DBusWatch *watch)
{
  watch->refcount += 1;
 
  return watch;
}
 
void
_dbus_watch_unref (DBusWatch *watch)
{
  _dbus_assert (watch != NULL);
  _dbus_assert (watch->refcount > 0);
 
  watch->refcount -= 1;
  if (watch->refcount == 0)
    {
      if (_dbus_pollable_is_valid (watch->fd))
        _dbus_warn ("this watch should have been invalidated");
 
      dbus_watch_set_data (watch, NULL, NULL); /* call free_data_function */
 
      if (watch->free_handler_data_function)
        (* watch->free_handler_data_function) (watch->handler_data);
      
      dbus_free (watch);
    }
}
 
void
_dbus_watch_invalidate (DBusWatch *watch)
{
  _dbus_pollable_invalidate (&watch->fd);
  watch->flags = 0;
}
 
void
_dbus_watch_sanitize_condition (DBusWatch    *watch,
                                unsigned int *condition)
{
  if (!(watch->flags & DBUS_WATCH_READABLE))
    *condition &= ~DBUS_WATCH_READABLE;
  if (!(watch->flags & DBUS_WATCH_WRITABLE))
    *condition &= ~DBUS_WATCH_WRITABLE;
}
 
 
struct DBusWatchList
{
  DBusList *watches;           
  DBusAddWatchFunction add_watch_function;    
  DBusRemoveWatchFunction remove_watch_function; 
  DBusWatchToggledFunction watch_toggled_function; 
  void *watch_data;                           
  DBusFreeFunction watch_free_data_function;  
};
 
DBusWatchList*
_dbus_watch_list_new (void)
{
  DBusWatchList *watch_list;
 
  watch_list = dbus_new0 (DBusWatchList, 1);
  if (watch_list == NULL)
    return NULL;
 
  return watch_list;
}
 
void
_dbus_watch_list_free (DBusWatchList *watch_list)
{
  /* free watch_data and removes watches as a side effect */
  _dbus_watch_list_set_functions (watch_list,
                                  NULL, NULL, NULL, NULL, NULL);
 
  _dbus_list_clear_full (&watch_list->watches,
                         (DBusFreeFunction) _dbus_watch_unref);
 
  dbus_free (watch_list);
}
 
#ifdef DBUS_ENABLE_VERBOSE_MODE
static const char*
watch_flags_to_string (int flags)
{
  const char *watch_type;
 
  if ((flags & DBUS_WATCH_READABLE) &&
      (flags & DBUS_WATCH_WRITABLE))
    watch_type = "readwrite";
  else if (flags & DBUS_WATCH_READABLE)
    watch_type = "read";
  else if (flags & DBUS_WATCH_WRITABLE)
    watch_type = "write";
  else
    watch_type = "not read or write";
  return watch_type;
}
#endif /* DBUS_ENABLE_VERBOSE_MODE */
 
dbus_bool_t
_dbus_watch_list_set_functions (DBusWatchList           *watch_list,
                                DBusAddWatchFunction     add_function,
                                DBusRemoveWatchFunction  remove_function,
                                DBusWatchToggledFunction toggled_function,
                                void                    *data,
                                DBusFreeFunction         free_data_function)
{
  /* Add watches with the new watch function, failing on OOM */
  if (add_function != NULL)
    {
      DBusList *link;
      
      link = _dbus_list_get_first_link (&watch_list->watches);
      while (link != NULL)
        {
          DBusList *next = _dbus_list_get_next_link (&watch_list->watches,
                                                     link);
#ifdef DBUS_ENABLE_VERBOSE_MODE
          DBusWatch *watch = link->data;
 
          _dbus_verbose ("Adding a %s watch on fd %" DBUS_POLLABLE_FORMAT " using newly-set add watch function\n",
                         watch_flags_to_string (dbus_watch_get_flags (link->data)),
                         _dbus_pollable_printable (watch->fd));
#endif
          
          if (!(* add_function) (link->data, data))
            {
              /* remove it all again and return FALSE */
              DBusList *link2;
              
              link2 = _dbus_list_get_first_link (&watch_list->watches);
              while (link2 != link)
                {
                  DBusList *next2 = _dbus_list_get_next_link (&watch_list->watches,
                                                              link2);
#ifdef DBUS_ENABLE_VERBOSE_MODE
                  DBusWatch *watch2 = link2->data;
                  
                  _dbus_verbose ("Removing watch on fd %" DBUS_POLLABLE_FORMAT " using newly-set remove function because initial add failed\n",
                                 _dbus_pollable_printable (watch2->fd));
#endif
                  
                  (* remove_function) (link2->data, data);
                  
                  link2 = next2;
                }
 
              return FALSE;
            }
      
          link = next;
        }
    }
  
  /* Remove all current watches from previous watch handlers */
 
  if (watch_list->remove_watch_function != NULL)
    {
      _dbus_verbose ("Removing all pre-existing watches\n");
      
      _dbus_list_foreach (&watch_list->watches,
                          (DBusForeachFunction) watch_list->remove_watch_function,
                          watch_list->watch_data);
    }
 
  if (watch_list->watch_free_data_function != NULL)
    (* watch_list->watch_free_data_function) (watch_list->watch_data);
  
  watch_list->add_watch_function = add_function;
  watch_list->remove_watch_function = remove_function;
  watch_list->watch_toggled_function = toggled_function;
  watch_list->watch_data = data;
  watch_list->watch_free_data_function = free_data_function;
 
  return TRUE;
}
 
dbus_bool_t
_dbus_watch_list_add_watch (DBusWatchList *watch_list,
                            DBusWatch     *watch)
{
  if (!_dbus_list_append (&watch_list->watches, watch))
    return FALSE;
  
  _dbus_watch_ref (watch);
 
  if (watch_list->add_watch_function != NULL)
    {
      _dbus_verbose ("Adding watch on fd %" DBUS_POLLABLE_FORMAT "\n",
                     _dbus_pollable_printable (watch->fd));
      
      if (!(* watch_list->add_watch_function) (watch,
                                               watch_list->watch_data))
        {
          _dbus_list_remove_last (&watch_list->watches, watch);
          _dbus_watch_unref (watch);
          return FALSE;
        }
    }
  
  return TRUE;
}
 
void
_dbus_watch_list_remove_watch  (DBusWatchList *watch_list,
                                DBusWatch     *watch)
{
  if (!_dbus_list_remove (&watch_list->watches, watch))
    _dbus_assert_not_reached ("Nonexistent watch was removed");
  
  if (watch_list->remove_watch_function != NULL)
    {
      _dbus_verbose ("Removing watch on fd %" DBUS_POLLABLE_FORMAT "\n",
                     _dbus_pollable_printable (watch->fd));
      
      (* watch_list->remove_watch_function) (watch,
                                             watch_list->watch_data);
    }
  
  _dbus_watch_unref (watch);
}
 
void
_dbus_watch_list_toggle_watch (DBusWatchList           *watch_list,
                               DBusWatch               *watch,
                               dbus_bool_t              enabled)
{
  enabled = !!enabled;
  
  if (enabled == watch->enabled)
    return;
 
  watch->enabled = enabled;
  
  if (watch_list->watch_toggled_function != NULL)
    {
      _dbus_verbose ("Toggling watch %p on fd %" DBUS_POLLABLE_FORMAT " to %d\n",
                     watch,
                     _dbus_pollable_printable (watch->fd),
                     watch->enabled);
      
      (* watch_list->watch_toggled_function) (watch,
                                              watch_list->watch_data);
    }
}
 
void
_dbus_watch_list_toggle_all_watches (DBusWatchList           *watch_list,
                                     dbus_bool_t              enabled)
{
  DBusList *link;
 
  for (link = _dbus_list_get_first_link (&watch_list->watches);
       link != NULL;
       link = _dbus_list_get_next_link (&watch_list->watches, link))
    {
      _dbus_watch_list_toggle_watch (watch_list, link->data, enabled);
    }
}
 
void
_dbus_watch_set_handler (DBusWatch        *watch,
                         DBusWatchHandler  handler,
                         void             *data,
                         DBusFreeFunction  free_data_function)
{
  if (watch->free_handler_data_function)
    (* watch->free_handler_data_function) (watch->handler_data);
 
  watch->handler = handler;
  watch->handler_data = data;
  watch->free_handler_data_function = free_data_function;
}
 
int
dbus_watch_get_fd (DBusWatch *watch)
{
  _dbus_return_val_if_fail (watch != NULL, -1);
 
  return dbus_watch_get_unix_fd(watch);
}
 
int
dbus_watch_get_unix_fd (DBusWatch *watch)
{
  _dbus_return_val_if_fail (watch != NULL, -1);
 
  /* FIXME remove #ifdef and do this on a lower level
   * (watch should have set_socket and set_unix_fd and track
   * which it has, and the transport should provide the
   * appropriate watch type)
   */
#ifdef DBUS_UNIX
  return watch->fd;
#else
  return dbus_watch_get_socket( watch );
#endif
}
 
int
dbus_watch_get_socket (DBusWatch *watch)
{
  _dbus_return_val_if_fail (watch != NULL, -1);
 
#ifdef DBUS_UNIX
  return watch->fd;
#else
  return _dbus_socket_get_int (watch->fd);
#endif
}
 
DBusSocket
_dbus_watch_get_socket (DBusWatch *watch)
{
  DBusSocket s;
 
  _dbus_assert (watch != NULL);
 
#ifdef DBUS_UNIX
  s.fd = watch->fd;
#else
  s = watch->fd;
#endif
 
  return s;
}
 
DBusPollable
_dbus_watch_get_pollable (DBusWatch *watch)
{
  _dbus_assert (watch != NULL);
 
  return watch->fd;
}
 
unsigned int
dbus_watch_get_flags (DBusWatch *watch)
{
  _dbus_return_val_if_fail (watch != NULL, 0);
  _dbus_assert ((watch->flags & VALID_WATCH_FLAGS) == watch->flags);
 
  return watch->flags;
}
 
void*
dbus_watch_get_data (DBusWatch *watch)
{
  _dbus_return_val_if_fail (watch != NULL, NULL);
 
  return watch->data;
}
 
void
dbus_watch_set_data (DBusWatch        *watch,
                     void             *data,
                     DBusFreeFunction  free_data_function)
{
  _dbus_return_if_fail (watch != NULL);
 
  _dbus_verbose ("Setting watch fd %" DBUS_POLLABLE_FORMAT " data to data = %p function = %p from data = %p function = %p\n",
                 _dbus_pollable_printable (watch->fd),
                 data, free_data_function, watch->data, watch->free_data_function);
  
  if (watch->free_data_function != NULL)
    (* watch->free_data_function) (watch->data);
  
  watch->data = data;
  watch->free_data_function = free_data_function;
}
 
dbus_bool_t
dbus_watch_get_enabled (DBusWatch *watch)
{
  _dbus_return_val_if_fail (watch != NULL, FALSE);
 
  return watch->enabled;
}
 
 
dbus_bool_t
dbus_watch_handle (DBusWatch    *watch,
                   unsigned int  flags)
{
  _dbus_return_val_if_fail (watch != NULL, FALSE);
 
#ifndef DBUS_DISABLE_CHECKS
  if (!_dbus_pollable_is_valid (watch->fd) || watch->flags == 0)
    {
      _dbus_warn_check_failed ("Watch is invalid, it should have been removed");
      return TRUE;
    }
#endif
    
  _dbus_return_val_if_fail (_dbus_pollable_is_valid (watch->fd) /* fails if watch was removed */, TRUE);
  
  _dbus_watch_sanitize_condition (watch, &flags);
 
  if (flags == 0)
    {
      _dbus_verbose ("After sanitization, watch flags on fd %" DBUS_POLLABLE_FORMAT " were 0\n",
                     _dbus_pollable_printable (watch->fd));
      return TRUE;
    }
  else
    return (* watch->handler) (watch, flags,
                               watch->handler_data);
}