1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 #include "dbus-internals.h"
26 #include "dbus-connection-internal.h"
27 #include "dbus-message-internal.h"
28 #include "dbus-pending-call-internal.h"
29 #include "dbus-pending-call.h"
30 #include "dbus-list.h"
31 #include "dbus-threads.h"
32 #include "dbus-test.h"
35 * @defgroup DBusPendingCallInternals DBusPendingCall implementation details
36 * @ingroup DBusInternals
37 * @brief DBusPendingCall private implementation details.
39 * The guts of DBusPendingCall and its methods.
45 * @brief Internals of DBusPendingCall
47 * Opaque object representing a reply message that we're waiting for.
51 * shorter and more visible way to write _dbus_connection_lock()
53 #define CONNECTION_LOCK(connection) _dbus_connection_lock(connection)
55 * shorter and more visible way to write _dbus_connection_unlock()
57 #define CONNECTION_UNLOCK(connection) _dbus_connection_unlock(connection)
60 * Implementation details of #DBusPendingCall - all fields are private.
62 struct DBusPendingCall
64 DBusAtomic refcount; /**< reference count */
66 DBusDataSlotList slot_list; /**< Data stored by allocated integer ID */
68 DBusPendingCallNotifyFunction function; /**< Notifier when reply arrives. */
70 DBusConnection *connection; /**< Connections we're associated with */
71 DBusMessage *reply; /**< Reply (after we've received it) */
72 DBusTimeout *timeout; /**< Timeout */
74 DBusList *timeout_link; /**< Preallocated timeout response */
76 dbus_uint32_t reply_serial; /**< Expected serial of reply */
78 unsigned int completed : 1; /**< TRUE if completed */
79 unsigned int timeout_added : 1; /**< Have added the timeout */
82 static dbus_int32_t notify_user_data_slot = -1;
85 * Creates a new pending reply object.
87 * @param connection connection where reply will arrive
88 * @param timeout_milliseconds length of timeout, -1 (or
89 * #DBUS_TIMEOUT_USE_DEFAULT) for default,
90 * #DBUS_TIMEOUT_INFINITE for no timeout
91 * @param timeout_handler timeout handler, takes pending call as data
92 * @returns a new #DBusPendingCall or #NULL if no memory.
95 _dbus_pending_call_new_unlocked (DBusConnection *connection,
96 int timeout_milliseconds,
97 DBusTimeoutHandler timeout_handler)
99 DBusPendingCall *pending;
100 DBusTimeout *timeout;
102 _dbus_assert (timeout_milliseconds >= 0 || timeout_milliseconds == -1);
104 if (timeout_milliseconds == -1)
105 timeout_milliseconds = _DBUS_DEFAULT_TIMEOUT_VALUE;
107 if (!dbus_pending_call_allocate_data_slot (¬ify_user_data_slot))
110 pending = dbus_new0 (DBusPendingCall, 1);
114 dbus_pending_call_free_data_slot (¬ify_user_data_slot);
118 if (timeout_milliseconds != DBUS_TIMEOUT_INFINITE)
120 timeout = _dbus_timeout_new (timeout_milliseconds,
126 dbus_pending_call_free_data_slot (¬ify_user_data_slot);
131 pending->timeout = timeout;
135 pending->timeout = NULL;
138 _dbus_atomic_inc (&pending->refcount);
139 pending->connection = connection;
140 _dbus_connection_ref_unlocked (pending->connection);
142 _dbus_data_slot_list_init (&pending->slot_list);
148 * Sets the reply of a pending call with the given message,
149 * or if the message is #NULL, by timing out the pending call.
151 * @param pending the pending call
152 * @param message the message to complete the call with, or #NULL
153 * to time out the call
156 _dbus_pending_call_set_reply_unlocked (DBusPendingCall *pending,
157 DBusMessage *message)
161 message = pending->timeout_link->data;
162 _dbus_list_clear (&pending->timeout_link);
165 dbus_message_ref (message);
167 _dbus_verbose (" handing message %p (%s) to pending call serial %u\n",
169 dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_METHOD_RETURN ?
171 dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_ERROR ?
172 "error" : "other type",
173 pending->reply_serial);
175 _dbus_assert (pending->reply == NULL);
176 _dbus_assert (pending->reply_serial == dbus_message_get_reply_serial (message));
177 pending->reply = message;
181 * Calls notifier function for the pending call
182 * and sets the call to completed.
184 * @param pending the pending call
188 _dbus_pending_call_complete (DBusPendingCall *pending)
190 _dbus_assert (!pending->completed);
192 pending->completed = TRUE;
194 if (pending->function)
197 user_data = dbus_pending_call_get_data (pending,
198 notify_user_data_slot);
200 (* pending->function) (pending, user_data);
205 * If the pending call hasn't been timed out, add its timeout
206 * error reply to the connection's incoming message queue.
208 * @param pending the pending call
209 * @param connection the connection the call was sent to
212 _dbus_pending_call_queue_timeout_error_unlocked (DBusPendingCall *pending,
213 DBusConnection *connection)
215 _dbus_assert (connection == pending->connection);
217 if (pending->timeout_link)
219 _dbus_connection_queue_synthesized_message_link (connection,
220 pending->timeout_link);
221 pending->timeout_link = NULL;
226 * Checks to see if a timeout has been added
228 * @param pending the pending_call
229 * @returns #TRUE if there is a timeout or #FALSE if not
232 _dbus_pending_call_is_timeout_added_unlocked (DBusPendingCall *pending)
234 _dbus_assert (pending != NULL);
236 return pending->timeout_added;
241 * Sets wether the timeout has been added
243 * @param pending the pending_call
244 * @param is_added whether or not a timeout is added
247 _dbus_pending_call_set_timeout_added_unlocked (DBusPendingCall *pending,
248 dbus_bool_t is_added)
250 _dbus_assert (pending != NULL);
252 pending->timeout_added = is_added;
257 * Retrives the timeout
259 * @param pending the pending_call
260 * @returns a timeout object or NULL if call has no timeout
263 _dbus_pending_call_get_timeout_unlocked (DBusPendingCall *pending)
265 _dbus_assert (pending != NULL);
267 return pending->timeout;
271 * Gets the reply's serial number
273 * @param pending the pending_call
274 * @returns a serial number for the reply or 0
277 _dbus_pending_call_get_reply_serial_unlocked (DBusPendingCall *pending)
279 _dbus_assert (pending != NULL);
281 return pending->reply_serial;
285 * Sets the reply's serial number
287 * @param pending the pending_call
288 * @param serial the serial number
291 _dbus_pending_call_set_reply_serial_unlocked (DBusPendingCall *pending,
292 dbus_uint32_t serial)
294 _dbus_assert (pending != NULL);
295 _dbus_assert (pending->reply_serial == 0);
297 pending->reply_serial = serial;
301 * Gets the connection associated with this pending call.
303 * @param pending the pending_call
304 * @returns the connection associated with the pending call
307 _dbus_pending_call_get_connection_and_lock (DBusPendingCall *pending)
309 _dbus_assert (pending != NULL);
311 CONNECTION_LOCK (pending->connection);
312 return pending->connection;
316 * Gets the connection associated with this pending call.
318 * @param pending the pending_call
319 * @returns the connection associated with the pending call
322 _dbus_pending_call_get_connection_unlocked (DBusPendingCall *pending)
324 _dbus_assert (pending != NULL);
326 return pending->connection;
330 * Sets the reply message associated with the pending call to a timeout error
332 * @param pending the pending_call
333 * @param message the message we are sending the error reply to
334 * @param serial serial number for the reply
335 * @return #FALSE on OOM
338 _dbus_pending_call_set_timeout_error_unlocked (DBusPendingCall *pending,
339 DBusMessage *message,
340 dbus_uint32_t serial)
342 DBusList *reply_link;
345 reply = dbus_message_new_error (message, DBUS_ERROR_NO_REPLY,
346 "Did not receive a reply. Possible causes include: "
347 "the remote application did not send a reply, "
348 "the message bus security policy blocked the reply, "
349 "the reply timeout expired, or "
350 "the network connection was broken.");
354 reply_link = _dbus_list_alloc_link (reply);
355 if (reply_link == NULL)
357 /* it's OK to unref this, nothing that could have attached a callback
358 * has ever seen it */
359 dbus_message_unref (reply);
363 pending->timeout_link = reply_link;
365 _dbus_pending_call_set_reply_serial_unlocked (pending, serial);
371 * Increments the reference count on a pending call,
372 * while the lock on its connection is already held.
374 * @param pending the pending call object
375 * @returns the pending call object
378 _dbus_pending_call_ref_unlocked (DBusPendingCall *pending)
380 _dbus_atomic_inc (&pending->refcount);
387 _dbus_pending_call_last_unref (DBusPendingCall *pending)
389 DBusConnection *connection;
391 /* If we get here, we should be already detached
392 * from the connection, or never attached.
394 _dbus_assert (!pending->timeout_added);
396 connection = pending->connection;
398 /* this assumes we aren't holding connection lock... */
399 _dbus_data_slot_list_free (&pending->slot_list);
401 if (pending->timeout != NULL)
402 _dbus_timeout_unref (pending->timeout);
404 if (pending->timeout_link)
406 dbus_message_unref ((DBusMessage *)pending->timeout_link->data);
407 _dbus_list_free_link (pending->timeout_link);
408 pending->timeout_link = NULL;
413 dbus_message_unref (pending->reply);
414 pending->reply = NULL;
419 dbus_pending_call_free_data_slot (¬ify_user_data_slot);
421 /* connection lock should not be held. */
422 /* Free the connection last to avoid a weird state while
423 * calling out to application code where the pending exists
424 * but not the connection.
426 dbus_connection_unref (connection);
430 * Decrements the reference count on a pending call,
431 * freeing it if the count reaches 0. Assumes
432 * connection lock is already held.
434 * @param pending the pending call object
437 _dbus_pending_call_unref_and_unlock (DBusPendingCall *pending)
439 dbus_int32_t old_refcount;
441 old_refcount = _dbus_atomic_dec (&pending->refcount);
442 _dbus_assert (old_refcount > 0);
444 CONNECTION_UNLOCK (pending->connection);
446 if (old_refcount == 1)
447 _dbus_pending_call_last_unref (pending);
451 * Checks whether the pending call has received a reply
452 * yet, or not. Assumes connection lock is held.
454 * @param pending the pending call
455 * @returns #TRUE if a reply has been received
458 _dbus_pending_call_get_completed_unlocked (DBusPendingCall *pending)
460 return pending->completed;
463 static DBusDataSlotAllocator slot_allocator;
464 _DBUS_DEFINE_GLOBAL_LOCK (pending_call_slots);
467 * Stores a pointer on a #DBusPendingCall, along
468 * with an optional function to be used for freeing
469 * the data when the data is set again, or when
470 * the pending call is finalized. The slot number
471 * must have been allocated with dbus_pending_call_allocate_data_slot().
473 * @param pending the pending_call
474 * @param slot the slot number
475 * @param data the data to store
476 * @param free_data_func finalizer function for the data
477 * @returns #TRUE if there was enough memory to store the data
480 _dbus_pending_call_set_data_unlocked (DBusPendingCall *pending,
483 DBusFreeFunction free_data_func)
485 DBusFreeFunction old_free_func;
489 retval = _dbus_data_slot_list_set (&slot_allocator,
491 slot, data, free_data_func,
492 &old_free_func, &old_data);
494 /* Drop locks to call out to app code */
495 CONNECTION_UNLOCK (pending->connection);
500 (* old_free_func) (old_data);
503 CONNECTION_LOCK (pending->connection);
511 * @defgroup DBusPendingCall DBusPendingCall
513 * @brief Pending reply to a method call message
515 * A DBusPendingCall is an object representing an
516 * expected reply. A #DBusPendingCall can be created
517 * when you send a message that should have a reply.
523 * @def DBUS_TIMEOUT_INFINITE
525 * An integer constant representing an infinite timeout. This has the
526 * numeric value 0x7fffffff (the largest 32-bit signed integer).
528 * For source compatibility with D-Bus versions earlier than 1.4.12, use
529 * 0x7fffffff, or INT32_MAX (assuming your platform has it).
533 * @def DBUS_TIMEOUT_USE_DEFAULT
535 * An integer constant representing a request to use the default timeout.
536 * This has numeric value -1.
538 * For source compatibility with D-Bus versions earlier than 1.4.12, use a
543 * @typedef DBusPendingCall
545 * Opaque data type representing a message pending.
549 * Increments the reference count on a pending call.
551 * @param pending the pending call object
552 * @returns the pending call object
555 dbus_pending_call_ref (DBusPendingCall *pending)
557 _dbus_return_val_if_fail (pending != NULL, NULL);
559 _dbus_atomic_inc (&pending->refcount);
565 * Decrements the reference count on a pending call,
566 * freeing it if the count reaches 0.
568 * @param pending the pending call object
571 dbus_pending_call_unref (DBusPendingCall *pending)
573 dbus_bool_t last_unref;
575 _dbus_return_if_fail (pending != NULL);
577 last_unref = (_dbus_atomic_dec (&pending->refcount) == 1);
580 _dbus_pending_call_last_unref(pending);
584 * Sets a notification function to be called when the reply is
585 * received or the pending call times out.
587 * @param pending the pending call
588 * @param function notifier function
589 * @param user_data data to pass to notifier function
590 * @param free_user_data function to free the user data
591 * @returns #FALSE if not enough memory
594 dbus_pending_call_set_notify (DBusPendingCall *pending,
595 DBusPendingCallNotifyFunction function,
597 DBusFreeFunction free_user_data)
599 _dbus_return_val_if_fail (pending != NULL, FALSE);
601 CONNECTION_LOCK (pending->connection);
603 /* could invoke application code! */
604 if (!_dbus_pending_call_set_data_unlocked (pending, notify_user_data_slot,
605 user_data, free_user_data))
608 pending->function = function;
610 CONNECTION_UNLOCK (pending->connection);
616 * Cancels the pending call, such that any reply or error received
617 * will just be ignored. Drops the dbus library's internal reference
618 * to the #DBusPendingCall so will free the call if nobody else is
619 * holding a reference. However you usually get a reference from
620 * dbus_connection_send_with_reply() so probably your app owns a ref
623 * Note that canceling a pending call will <em>not</em> simulate a
624 * timed-out call; if a call times out, then a timeout error reply is
625 * received. If you cancel the call, no reply is received unless the
626 * the reply was already received before you canceled.
628 * @param pending the pending call
631 dbus_pending_call_cancel (DBusPendingCall *pending)
633 _dbus_return_if_fail (pending != NULL);
635 _dbus_connection_remove_pending_call (pending->connection,
640 * Checks whether the pending call has received a reply
643 * @param pending the pending call
644 * @returns #TRUE if a reply has been received
647 dbus_pending_call_get_completed (DBusPendingCall *pending)
649 dbus_bool_t completed;
651 _dbus_return_val_if_fail (pending != NULL, FALSE);
653 CONNECTION_LOCK (pending->connection);
654 completed = pending->completed;
655 CONNECTION_UNLOCK (pending->connection);
661 * Gets the reply, or returns #NULL if none has been received
662 * yet. Ownership of the reply message passes to the caller. This
663 * function can only be called once per pending call, since the reply
664 * message is tranferred to the caller.
666 * @param pending the pending call
667 * @returns the reply message or #NULL.
670 dbus_pending_call_steal_reply (DBusPendingCall *pending)
672 DBusMessage *message;
674 _dbus_return_val_if_fail (pending != NULL, NULL);
675 _dbus_return_val_if_fail (pending->completed, NULL);
676 _dbus_return_val_if_fail (pending->reply != NULL, NULL);
678 CONNECTION_LOCK (pending->connection);
680 message = pending->reply;
681 pending->reply = NULL;
683 CONNECTION_UNLOCK (pending->connection);
685 _dbus_message_trace_ref (message, -1, -1, "dbus_pending_call_steal_reply");
690 * Block until the pending call is completed. The blocking is as with
691 * dbus_connection_send_with_reply_and_block(); it does not enter the
692 * main loop or process other messages, it simply waits for the reply
695 * If the pending call is already completed, this function returns
698 * @todo when you start blocking, the timeout is reset, but it should
699 * really only use time remaining since the pending call was created.
700 * This requires storing timestamps instead of intervals in the timeout
702 * @param pending the pending call
705 dbus_pending_call_block (DBusPendingCall *pending)
707 _dbus_return_if_fail (pending != NULL);
709 _dbus_connection_block_pending_call (pending);
713 * Allocates an integer ID to be used for storing application-specific
714 * data on any DBusPendingCall. The allocated ID may then be used
715 * with dbus_pending_call_set_data() and dbus_pending_call_get_data().
716 * The passed-in slot must be initialized to -1, and is filled in
717 * with the slot ID. If the passed-in slot is not -1, it's assumed
718 * to be already allocated, and its refcount is incremented.
720 * The allocated slot is global, i.e. all DBusPendingCall objects will
721 * have a slot with the given integer ID reserved.
723 * @param slot_p address of a global variable storing the slot
724 * @returns #FALSE on failure (no memory)
727 dbus_pending_call_allocate_data_slot (dbus_int32_t *slot_p)
729 _dbus_return_val_if_fail (slot_p != NULL, FALSE);
731 return _dbus_data_slot_allocator_alloc (&slot_allocator,
732 &_DBUS_LOCK_NAME (pending_call_slots),
737 * Deallocates a global ID for #DBusPendingCall data slots.
738 * dbus_pending_call_get_data() and dbus_pending_call_set_data() may
739 * no longer be used with this slot. Existing data stored on existing
740 * DBusPendingCall objects will be freed when the #DBusPendingCall is
741 * finalized, but may not be retrieved (and may only be replaced if
742 * someone else reallocates the slot). When the refcount on the
743 * passed-in slot reaches 0, it is set to -1.
745 * @param slot_p address storing the slot to deallocate
748 dbus_pending_call_free_data_slot (dbus_int32_t *slot_p)
750 _dbus_return_if_fail (slot_p != NULL);
751 _dbus_return_if_fail (*slot_p >= 0);
753 _dbus_data_slot_allocator_free (&slot_allocator, slot_p);
757 * Stores a pointer on a #DBusPendingCall, along
758 * with an optional function to be used for freeing
759 * the data when the data is set again, or when
760 * the pending call is finalized. The slot number
761 * must have been allocated with dbus_pending_call_allocate_data_slot().
763 * @param pending the pending_call
764 * @param slot the slot number
765 * @param data the data to store
766 * @param free_data_func finalizer function for the data
767 * @returns #TRUE if there was enough memory to store the data
770 dbus_pending_call_set_data (DBusPendingCall *pending,
773 DBusFreeFunction free_data_func)
777 _dbus_return_val_if_fail (pending != NULL, FALSE);
778 _dbus_return_val_if_fail (slot >= 0, FALSE);
781 CONNECTION_LOCK (pending->connection);
782 retval = _dbus_pending_call_set_data_unlocked (pending, slot, data, free_data_func);
783 CONNECTION_UNLOCK (pending->connection);
788 * Retrieves data previously set with dbus_pending_call_set_data().
789 * The slot must still be allocated (must not have been freed).
791 * @param pending the pending_call
792 * @param slot the slot to get data from
793 * @returns the data, or #NULL if not found
796 dbus_pending_call_get_data (DBusPendingCall *pending,
801 _dbus_return_val_if_fail (pending != NULL, NULL);
803 CONNECTION_LOCK (pending->connection);
804 res = _dbus_data_slot_list_get (&slot_allocator,
807 CONNECTION_UNLOCK (pending->connection);