1 /* -*- mode: C; c-file-style: "gnu" -*- */
2 /* dbus-pending-call.c Object representing a call in progress.
4 * Copyright (C) 2002, 2003 Red Hat Inc.
6 * Licensed under the Academic Free License version 2.1
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include "dbus-internals.h"
25 #include "dbus-connection-internal.h"
26 #include "dbus-pending-call-internal.h"
27 #include "dbus-pending-call.h"
28 #include "dbus-list.h"
29 #include "dbus-threads.h"
30 #include "dbus-test.h"
33 * @defgroup DBusPendingCallInternals DBusPendingCall implementation details
34 * @ingroup DBusInternals
35 * @brief DBusPendingCall private implementation details.
37 * The guts of DBusPendingCall and its methods.
43 * @brief Internals of DBusPendingCall
45 * Opaque object representing a reply message that we're waiting for.
47 struct DBusPendingCall
49 DBusAtomic refcount; /**< reference count */
51 DBusDataSlotList slot_list; /**< Data stored by allocated integer ID */
53 DBusPendingCallNotifyFunction function; /**< Notifier when reply arrives. */
55 DBusConnection *connection; /**< Connections we're associated with */
56 DBusMessage *reply; /**< Reply (after we've received it) */
57 DBusTimeout *timeout; /**< Timeout */
59 DBusList *timeout_link; /**< Preallocated timeout response */
61 dbus_uint32_t reply_serial; /**< Expected serial of reply */
63 unsigned int completed : 1; /**< TRUE if completed */
64 unsigned int timeout_added : 1; /**< Have added the timeout */
67 static dbus_int32_t notify_user_data_slot = -1;
70 * Creates a new pending reply object.
72 * @param connection connection where reply will arrive
73 * @param timeout_milliseconds length of timeout, -1 for default
74 * @param timeout_handler timeout handler, takes pending call as data
75 * @returns a new #DBusPendingCall or #NULL if no memory.
78 _dbus_pending_call_new (DBusConnection *connection,
79 int timeout_milliseconds,
80 DBusTimeoutHandler timeout_handler)
82 DBusPendingCall *pending;
85 _dbus_assert (timeout_milliseconds >= 0 || timeout_milliseconds == -1);
87 if (timeout_milliseconds == -1)
88 timeout_milliseconds = _DBUS_DEFAULT_TIMEOUT_VALUE;
90 /* it would probably seem logical to pass in _DBUS_INT_MAX for
91 * infinite timeout, but then math in
92 * _dbus_connection_block_for_reply would get all overflow-prone, so
95 if (timeout_milliseconds > _DBUS_ONE_HOUR_IN_MILLISECONDS * 6)
96 timeout_milliseconds = _DBUS_ONE_HOUR_IN_MILLISECONDS * 6;
98 if (!dbus_pending_call_allocate_data_slot (¬ify_user_data_slot))
101 pending = dbus_new0 (DBusPendingCall, 1);
105 dbus_pending_call_free_data_slot (¬ify_user_data_slot);
109 timeout = _dbus_timeout_new (timeout_milliseconds,
115 dbus_pending_call_free_data_slot (¬ify_user_data_slot);
120 pending->refcount.value = 1;
121 pending->connection = connection;
122 pending->timeout = timeout;
124 _dbus_data_slot_list_init (&pending->slot_list);
130 * Sets the reply of a pending call with the given message,
131 * or if the message is #NULL, by timing out the pending call.
133 * @param pending the pending call
134 * @param message the message to complete the call with, or #NULL
135 * to time out the call
138 _dbus_pending_call_set_reply (DBusPendingCall *pending,
139 DBusMessage *message)
143 message = pending->timeout_link->data;
144 _dbus_list_clear (&pending->timeout_link);
147 dbus_message_ref (message);
149 _dbus_verbose (" handing message %p (%s) to pending call serial %u\n",
151 dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_METHOD_RETURN ?
153 dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_ERROR ?
154 "error" : "other type",
155 pending->reply_serial);
157 _dbus_assert (pending->reply == NULL);
158 _dbus_assert (pending->reply_serial == dbus_message_get_reply_serial (message));
159 pending->reply = message;
163 * Calls notifier function for the pending call
164 * and sets the call to completed.
166 * @param pending the pending call
170 _dbus_pending_call_complete (DBusPendingCall *pending)
172 _dbus_assert (!pending->completed);
174 pending->completed = TRUE;
176 if (pending->function)
179 user_data = dbus_pending_call_get_data (pending,
180 notify_user_data_slot);
182 (* pending->function) (pending, user_data);
187 _dbus_pending_call_queue_timeout_error (DBusPendingCall *pending,
188 DBusConnection *connection)
190 if (pending->timeout_link)
192 _dbus_connection_queue_synthesized_message_link (connection,
193 pending->timeout_link);
194 pending->timeout_link = NULL;
199 * Checks to see if a timeout has been added
201 * @param pending the pending_call
202 * @returns #TRUE if there is a timeout or #FALSE if not
205 _dbus_pending_call_is_timeout_added (DBusPendingCall *pending)
207 _dbus_assert (pending != NULL);
209 return pending->timeout_added;
214 * Sets wether the timeout has been added
216 * @param pending the pending_call
217 * @param is_added whether or not a timeout is added
220 _dbus_pending_call_set_timeout_added (DBusPendingCall *pending,
221 dbus_bool_t is_added)
223 _dbus_assert (pending != NULL);
225 pending->timeout_added = is_added;
230 * Retrives the timeout
232 * @param pending the pending_call
233 * @returns a timeout object
236 _dbus_pending_call_get_timeout (DBusPendingCall *pending)
238 _dbus_assert (pending != NULL);
240 return pending->timeout;
244 * Gets the reply's serial number
246 * @param pending the pending_call
247 * @returns a serial number for the reply or 0
250 _dbus_pending_call_get_reply_serial (DBusPendingCall *pending)
252 _dbus_assert (pending != NULL);
254 return pending->reply_serial;
258 * Sets the reply's serial number
260 * @param pending the pending_call
261 * @param serial the serial number
264 _dbus_pending_call_set_reply_serial (DBusPendingCall *pending,
265 dbus_uint32_t serial)
267 _dbus_assert (pending != NULL);
268 _dbus_assert (pending->reply_serial == 0);
270 pending->reply_serial = serial;
274 * Gets the connection associated with this pending call
276 * @param pending the pending_call
277 * @returns the connection associated with the pending call
280 _dbus_pending_call_get_connection (DBusPendingCall *pending)
282 _dbus_assert (pending != NULL);
284 return pending->connection;
288 * Sets the connection associated with the pending call
290 * @param pending the pending_call
291 * @param connection the connection which is associated with the pending call
294 _dbus_pending_call_set_connection (DBusPendingCall *pending,
295 DBusConnection *connection)
297 _dbus_assert (pending != NULL);
299 pending->connection = connection;
303 * NULLs out the connection
305 * @param pending the pending_call
308 _dbus_pending_call_clear_connection (DBusPendingCall *pending)
310 _dbus_assert (pending != NULL);
312 pending->connection = NULL;
316 * Sets the reply message associated with the pending call to a timeout error
318 * @param pending the pending_call
319 * @param message the message we are sending the error reply to
320 * @param serial serial number for the reply
321 * @return #FALSE on OOM
324 _dbus_pending_call_set_timeout_error (DBusPendingCall *pending,
325 DBusMessage *message,
326 dbus_uint32_t serial)
328 DBusList *reply_link;
331 reply = dbus_message_new_error (message, DBUS_ERROR_NO_REPLY,
332 "No reply within specified time");
336 reply_link = _dbus_list_alloc_link (reply);
337 if (reply_link == NULL)
339 dbus_message_unref (reply);
343 pending->timeout_link = reply_link;
345 _dbus_pending_call_set_reply_serial (pending, serial);
353 * @defgroup DBusPendingCall DBusPendingCall
355 * @brief Pending reply to a method call message
357 * A DBusPendingCall is an object representing an
358 * expected reply. A #DBusPendingCall can be created
359 * when you send a message that should have a reply.
365 * @typedef DBusPendingCall
367 * Opaque data type representing a message pending.
371 * Increments the reference count on a pending call.
373 * @param pending the pending call object
374 * @returns the pending call object
377 dbus_pending_call_ref (DBusPendingCall *pending)
379 _dbus_return_val_if_fail (pending != NULL, NULL);
381 _dbus_atomic_inc (&pending->refcount);
387 * Decrements the reference count on a pending call,
388 * freeing it if the count reaches 0.
390 * @param pending the pending call object
393 dbus_pending_call_unref (DBusPendingCall *pending)
395 dbus_bool_t last_unref;
397 _dbus_return_if_fail (pending != NULL);
399 last_unref = (_dbus_atomic_dec (&pending->refcount) == 1);
403 /* If we get here, we should be already detached
404 * from the connection, or never attached.
406 _dbus_assert (pending->connection == NULL);
407 _dbus_assert (!pending->timeout_added);
409 /* this assumes we aren't holding connection lock... */
410 _dbus_data_slot_list_free (&pending->slot_list);
412 if (pending->timeout != NULL)
413 _dbus_timeout_unref (pending->timeout);
415 if (pending->timeout_link)
417 dbus_message_unref ((DBusMessage *)pending->timeout_link->data);
418 _dbus_list_free_link (pending->timeout_link);
419 pending->timeout_link = NULL;
424 dbus_message_unref (pending->reply);
425 pending->reply = NULL;
430 dbus_pending_call_free_data_slot (¬ify_user_data_slot);
435 * Sets a notification function to be called when the reply is
436 * received or the pending call times out.
438 * @param pending the pending call
439 * @param function notifier function
440 * @param user_data data to pass to notifier function
441 * @param free_user_data function to free the user data
442 * @returns #FALSE if not enough memory
445 dbus_pending_call_set_notify (DBusPendingCall *pending,
446 DBusPendingCallNotifyFunction function,
448 DBusFreeFunction free_user_data)
450 _dbus_return_val_if_fail (pending != NULL, FALSE);
452 /* could invoke application code! */
453 if (!dbus_pending_call_set_data (pending, notify_user_data_slot,
454 user_data, free_user_data))
457 pending->function = function;
463 * Cancels the pending call, such that any reply or error received
464 * will just be ignored. Drops the dbus library's internal reference
465 * to the #DBusPendingCall so will free the call if nobody else is
466 * holding a reference. However you usually get a reference
467 * from dbus_connection_send() so probably your app owns a ref also.
469 * @param pending the pending call
472 dbus_pending_call_cancel (DBusPendingCall *pending)
474 if (pending->connection)
475 _dbus_connection_remove_pending_call (pending->connection,
480 * Checks whether the pending call has received a reply
483 * @todo not thread safe? I guess it has to lock though it sucks
485 * @param pending the pending call
486 * @returns #TRUE if a reply has been received */
488 dbus_pending_call_get_completed (DBusPendingCall *pending)
490 return pending->completed;
494 * Gets the reply, or returns #NULL if none has been received
495 * yet. Ownership of the reply message passes to the caller. This
496 * function can only be called once per pending call, since the reply
497 * message is tranferred to the caller.
499 * @param pending the pending call
500 * @returns the reply message or #NULL.
503 dbus_pending_call_steal_reply (DBusPendingCall *pending)
505 DBusMessage *message;
507 _dbus_return_val_if_fail (pending->completed, NULL);
508 _dbus_return_val_if_fail (pending->reply != NULL, NULL);
510 message = pending->reply;
511 pending->reply = NULL;
517 * Block until the pending call is completed. The blocking is as with
518 * dbus_connection_send_with_reply_and_block(); it does not enter the
519 * main loop or process other messages, it simply waits for the reply
522 * If the pending call is already completed, this function returns
525 * @todo when you start blocking, the timeout is reset, but it should
526 * really only use time remaining since the pending call was created.
528 * @param pending the pending call
531 dbus_pending_call_block (DBusPendingCall *pending)
533 _dbus_connection_block_pending_call (pending);
536 static DBusDataSlotAllocator slot_allocator;
537 _DBUS_DEFINE_GLOBAL_LOCK (pending_call_slots);
540 * Allocates an integer ID to be used for storing application-specific
541 * data on any DBusPendingCall. The allocated ID may then be used
542 * with dbus_pending_call_set_data() and dbus_pending_call_get_data().
543 * The passed-in slot must be initialized to -1, and is filled in
544 * with the slot ID. If the passed-in slot is not -1, it's assumed
545 * to be already allocated, and its refcount is incremented.
547 * The allocated slot is global, i.e. all DBusPendingCall objects will
548 * have a slot with the given integer ID reserved.
550 * @param slot_p address of a global variable storing the slot
551 * @returns #FALSE on failure (no memory)
554 dbus_pending_call_allocate_data_slot (dbus_int32_t *slot_p)
556 return _dbus_data_slot_allocator_alloc (&slot_allocator,
557 _DBUS_LOCK_NAME (pending_call_slots),
562 * Deallocates a global ID for #DBusPendingCall data slots.
563 * dbus_pending_call_get_data() and dbus_pending_call_set_data() may
564 * no longer be used with this slot. Existing data stored on existing
565 * DBusPendingCall objects will be freed when the #DBusPendingCall is
566 * finalized, but may not be retrieved (and may only be replaced if
567 * someone else reallocates the slot). When the refcount on the
568 * passed-in slot reaches 0, it is set to -1.
570 * @param slot_p address storing the slot to deallocate
573 dbus_pending_call_free_data_slot (dbus_int32_t *slot_p)
575 _dbus_return_if_fail (*slot_p >= 0);
577 _dbus_data_slot_allocator_free (&slot_allocator, slot_p);
581 * Stores a pointer on a #DBusPendingCall, along
582 * with an optional function to be used for freeing
583 * the data when the data is set again, or when
584 * the pending call is finalized. The slot number
585 * must have been allocated with dbus_pending_call_allocate_data_slot().
587 * @param pending the pending_call
588 * @param slot the slot number
589 * @param data the data to store
590 * @param free_data_func finalizer function for the data
591 * @returns #TRUE if there was enough memory to store the data
594 dbus_pending_call_set_data (DBusPendingCall *pending,
597 DBusFreeFunction free_data_func)
599 DBusFreeFunction old_free_func;
603 _dbus_return_val_if_fail (pending != NULL, FALSE);
604 _dbus_return_val_if_fail (slot >= 0, FALSE);
606 retval = _dbus_data_slot_list_set (&slot_allocator,
608 slot, data, free_data_func,
609 &old_free_func, &old_data);
614 (* old_free_func) (old_data);
621 * Retrieves data previously set with dbus_pending_call_set_data().
622 * The slot must still be allocated (must not have been freed).
624 * @param pending the pending_call
625 * @param slot the slot to get data from
626 * @returns the data, or #NULL if not found
629 dbus_pending_call_get_data (DBusPendingCall *pending,
634 _dbus_return_val_if_fail (pending != NULL, NULL);
636 res = _dbus_data_slot_list_get (&slot_allocator,
645 #ifdef DBUS_BUILD_TESTS
648 * @ingroup DBusPendingCallInternals
649 * Unit test for DBusPendingCall.
651 * @returns #TRUE on success.
654 _dbus_pending_call_test (const char *test_data_dir)
659 #endif /* DBUS_BUILD_TESTS */