/* -*- mode: C; c-file-style: "gnu" -*- */

/* dbus-watch.c DBusWatch implementation

 *

 * Copyright (C) 2002, 2003  Red Hat Inc.

 * Portion Copyright © 2008 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 */

#include "dbus-internals.h"

#include "dbus-watch.h"

#include "dbus-list.h"

#ifdef __SYMBIAN32__

#include "config.h"

#endif //__SYMBIAN32__

/**

 * @defgroup DBusWatchInternals DBusWatch implementation details

 * @ingroup  DBusInternals

 * @brief implementation details for DBusWatch

 * 

 * @{

 */

/**

 * Implementation of DBusWatch

 */

struct DBusWatch

{

  int refcount;                        /**< Reference count */

  int fd;                              /**< File descriptor. */

  unsigned int flags;                  /**< Conditions to watch. */

  DBusWatchHandler handler;                    /**< Watch handler. */

  void *handler_data;                          /**< Watch handler data. */

  DBusFreeFunction free_handler_data_function; /**< Free the watch handler data. */

  void *data;                          /**< Application data. */

  DBusFreeFunction free_data_function; /**< Free the application data. */

  unsigned int enabled : 1;            /**< Whether it's enabled. */

};

/**

 * Creates a new DBusWatch. Used to add a file descriptor to be polled

 * by a main loop.

 * 

 * @param fd the file descriptor to be watched.

 * @param flags the conditions to watch for on the descriptor.

 * @param enabled the initial enabled state

 * @param handler the handler function

 * @param data data for handler function

 * @param free_data_function function to free the data

 * @returns the new DBusWatch object.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

DBusWatch*

_dbus_watch_new (int               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;

}

/**

 * Increments the reference count of a DBusWatch object.

 *

 * @param watch the watch object.

 * @returns the watch object.

 */

DBusWatch *

_dbus_watch_ref (DBusWatch *watch)

{

  watch->refcount += 1;

  return watch;

}

/**

 * Decrements the reference count of a DBusWatch object

 * and finalizes the object if the count reaches zero.

 *

 * @param watch the watch object.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

_dbus_watch_unref (DBusWatch *watch)

{

  _dbus_assert (watch != NULL);

  _dbus_assert (watch->refcount > 0);

  watch->refcount -= 1;

  if (watch->refcount == 0)

    {

      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);

    }

}

/**

 * Clears the file descriptor from a now-invalid watch object so that

 * no one tries to use it.  This is because a watch may stay alive due

 * to reference counts after the file descriptor is closed.

 * Invalidation makes it easier to catch bugs. It also

 * keeps people from doing dorky things like assuming file descriptors

 * are unique (never recycled).

 *

 * @param watch the watch object.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

_dbus_watch_invalidate (DBusWatch *watch)

{

  watch->fd = -1;

  watch->flags = 0;

}

/**

 * Sanitizes the given condition so that it only contains

 * flags that the DBusWatch requested. e.g. if the

 * watch is a DBUS_WATCH_READABLE watch then

 * DBUS_WATCH_WRITABLE will be stripped from the condition.

 *

 * @param watch the watch object.

 * @param condition address of the condition to sanitize.

 */

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;

}

/**

 * @typedef DBusWatchList

 *

 * Opaque data type representing a list of watches

 * and a set of DBusAddWatchFunction/DBusRemoveWatchFunction.

 * Automatically handles removing/re-adding watches

 * when the DBusAddWatchFunction is updated or changed.

 * Holds a reference count to each watch.

 *

 * Used in the implementation of both DBusServer and

 * DBusClient.

 *

 */

/**

 * DBusWatchList implementation details. All fields

 * are private.

 *

 */

struct DBusWatchList

{

  DBusList *watches;           /**< Watch objects. */

  DBusAddWatchFunction add_watch_function;    /**< Callback for adding a watch. */

  DBusRemoveWatchFunction remove_watch_function; /**< Callback for removing a watch. */

  DBusWatchToggledFunction watch_toggled_function; /**< Callback on toggling enablement */

  void *watch_data;                           /**< Data for watch callbacks */

  DBusFreeFunction watch_free_data_function;  /**< Free function for watch callback data */

};

/**

 * Creates a new watch list. Returns #NULL if insufficient

 * memory exists.

 *

 * @returns the new watch list, or #NULL on failure.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

DBusWatchList*

_dbus_watch_list_new (void)

{

  DBusWatchList *watch_list;

  watch_list = dbus_new0 (DBusWatchList, 1);

  if (watch_list == NULL)

    return NULL;

  return watch_list;

}

/**

 * Frees a DBusWatchList.

 *

 * @param watch_list the watch list.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

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_foreach (&watch_list->watches,

                      (DBusForeachFunction) _dbus_watch_unref,

                      NULL);

  _dbus_list_clear (&watch_list->watches);

  dbus_free (watch_list);

}

/**

 * Sets the watch functions. This function is the "backend"

 * for dbus_connection_set_watch_functions() and

 * dbus_server_set_watch_functions().

 *

 * @param watch_list the watch list.

 * @param add_function the add watch function.

 * @param remove_function the remove watch function.

 * @param toggled_function function on toggling enabled flag, or #NULL

 * @param data the data for those functions.

 * @param free_data_function the function to free the data.

 * @returns #FALSE if not enough memory

 *

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

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

          {

            const char *watch_type;

            int flags;

            flags = dbus_watch_get_flags (link->data);

            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";

            _dbus_verbose ("Adding a %s watch on fd %d using newly-set add watch function\n",

                           watch_type,

                           dbus_watch_get_fd (link->data));

          }

#endif /* DBUS_ENABLE_VERBOSE_MODE */

          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 *next = _dbus_list_get_next_link (&watch_list->watches,

                                                             link2);

                  _dbus_verbose ("Removing watch on fd %d using newly-set remove function because initial add failed\n",

                                 dbus_watch_get_fd (link2->data));

                  (* remove_function) (link2->data, data);

                  link2 = next;

                }

              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;

}

/**

 * Adds a new watch to the watch list, invoking the

 * application DBusAddWatchFunction if appropriate.

 *

 * @param watch_list the watch list.

 * @param watch the watch to add.

 * @returns #TRUE on success, #FALSE if no memory.

 */

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 %d\n",

                     dbus_watch_get_fd (watch));

      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;

}

/**

 * Removes a watch from the watch list, invoking the

 * application's DBusRemoveWatchFunction if appropriate.

 *

 * @param watch_list the watch list.

 * @param watch the watch to remove.

 */

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 %d\n",

                     dbus_watch_get_fd (watch));

      (* watch_list->remove_watch_function) (watch,

                                             watch_list->watch_data);

    }

  _dbus_watch_unref (watch);

}

/**

 * Sets a watch to the given enabled state, invoking the

 * application's DBusWatchToggledFunction if appropriate.

 *

 * @param watch_list the watch list.

 * @param watch the watch to toggle.

 * @param enabled #TRUE to enable

 */

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 %d to %d\n",

                     watch, dbus_watch_get_fd (watch), watch->enabled);

      (* watch_list->watch_toggled_function) (watch,

                                              watch_list->watch_data);

    }

}

/**

 * Sets the handler for the watch.

 *

 * @todo this function only exists because of the weird

 * way connection watches are done, see the note

 * in docs for _dbus_connection_handle_watch().

 *

 * @param watch the watch

 * @param handler the new handler

 * @param data the data

 * @param free_data_function free data with this

 */

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;

}

/** @} */

/**

 * @defgroup DBusWatch DBusWatch

 * @ingroup  DBus

 * @brief Object representing a file descriptor to be watched.

 *

 * Types and functions related to DBusWatch. A watch represents

 * a file descriptor that the main loop needs to monitor,

 * as in Qt's QSocketNotifier or GLib's g_io_add_watch().

 *

 * Use dbus_connection_set_watch_functions() or dbus_server_set_watch_functions()

 * to be notified when libdbus needs to add or remove watches.

 * 

 * @{

 */

/**

 * @typedef DBusWatch

 *

 * Opaque object representing a file descriptor

 * to be watched for changes in readability,

 * writability, or hangup.

 */

/**

 * Gets the file descriptor that should be watched.

 *

 * On Windows, this will be a socket. On UNIX right now it will be a

 * socket but in principle it could be something else.

 * 

 * @param watch the DBusWatch object.

 * @returns the file descriptor to watch.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif 

int

dbus_watch_get_fd (DBusWatch *watch)