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 */
83 _dbus_pending_call_trace_ref (DBusPendingCall *pending_call,
88 #ifdef DBUS_ENABLE_VERBOSE_MODE
89 static int enabled = -1;
91 _dbus_trace_ref ("DBusPendingCall", pending_call, old_refcount,
92 new_refcount, why, "DBUS_PENDING_CALL_TRACE", &enabled);
96 static dbus_int32_t notify_user_data_slot = -1;
99 * Creates a new pending reply object.
101 * @param connection connection where reply will arrive
102 * @param timeout_milliseconds length of timeout, -1 (or
103 * #DBUS_TIMEOUT_USE_DEFAULT) for default,
104 * #DBUS_TIMEOUT_INFINITE for no timeout
105 * @param timeout_handler timeout handler, takes pending call as data
106 * @returns a new #DBusPendingCall or #NULL if no memory.
109 _dbus_pending_call_new_unlocked (DBusConnection *connection,
110 int timeout_milliseconds,
111 DBusTimeoutHandler timeout_handler)
113 DBusPendingCall *pending;
114 DBusTimeout *timeout;
116 _dbus_assert (timeout_milliseconds >= 0 || timeout_milliseconds == -1);
118 if (timeout_milliseconds == -1)
119 timeout_milliseconds = _DBUS_DEFAULT_TIMEOUT_VALUE;
121 if (!dbus_pending_call_allocate_data_slot (¬ify_user_data_slot))
124 pending = dbus_new0 (DBusPendingCall, 1);
128 dbus_pending_call_free_data_slot (¬ify_user_data_slot);
132 if (timeout_milliseconds != DBUS_TIMEOUT_INFINITE)
134 timeout = _dbus_timeout_new (timeout_milliseconds,
140 dbus_pending_call_free_data_slot (¬ify_user_data_slot);
145 pending->timeout = timeout;
149 pending->timeout = NULL;
152 _dbus_atomic_inc (&pending->refcount);
153 pending->connection = connection;
154 _dbus_connection_ref_unlocked (pending->connection);
156 _dbus_data_slot_list_init (&pending->slot_list);
158 _dbus_pending_call_trace_ref (pending, 0, 1, "new_unlocked");
164 * Sets the reply of a pending call with the given message,
165 * or if the message is #NULL, by timing out the pending call.
167 * @param pending the pending call
168 * @param message the message to complete the call with, or #NULL
169 * to time out the call
172 _dbus_pending_call_set_reply_unlocked (DBusPendingCall *pending,
173 DBusMessage *message)
177 message = pending->timeout_link->data;
178 _dbus_list_clear (&pending->timeout_link);
181 dbus_message_ref (message);
183 _dbus_verbose (" handing message %p (%s) to pending call serial %u\n",
185 dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_METHOD_RETURN ?
187 dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_ERROR ?
188 "error" : "other type",
189 pending->reply_serial);
191 _dbus_assert (pending->reply == NULL);
192 _dbus_assert (pending->reply_serial == dbus_message_get_reply_serial (message));
193 pending->reply = message;
197 * Calls notifier function for the pending call
198 * and sets the call to completed.
200 * @param pending the pending call
204 _dbus_pending_call_complete (DBusPendingCall *pending)
206 _dbus_assert (!pending->completed);
208 pending->completed = TRUE;
210 if (pending->function)
213 user_data = dbus_pending_call_get_data (pending,
214 notify_user_data_slot);
216 (* pending->function) (pending, user_data);
221 * If the pending call hasn't been timed out, add its timeout
222 * error reply to the connection's incoming message queue.
224 * @param pending the pending call
225 * @param connection the connection the call was sent to
228 _dbus_pending_call_queue_timeout_error_unlocked (DBusPendingCall *pending,
229 DBusConnection *connection)
231 _dbus_assert (connection == pending->connection);
233 if (pending->timeout_link)
235 _dbus_connection_queue_synthesized_message_link (connection,
236 pending->timeout_link);
237 pending->timeout_link = NULL;
242 * Checks to see if a timeout has been added
244 * @param pending the pending_call
245 * @returns #TRUE if there is a timeout or #FALSE if not
248 _dbus_pending_call_is_timeout_added_unlocked (DBusPendingCall *pending)
250 _dbus_assert (pending != NULL);
252 return pending->timeout_added;
257 * Sets wether the timeout has been added
259 * @param pending the pending_call
260 * @param is_added whether or not a timeout is added
263 _dbus_pending_call_set_timeout_added_unlocked (DBusPendingCall *pending,
264 dbus_bool_t is_added)
266 _dbus_assert (pending != NULL);
268 pending->timeout_added = is_added;
273 * Retrives the timeout
275 * @param pending the pending_call
276 * @returns a timeout object or NULL if call has no timeout
279 _dbus_pending_call_get_timeout_unlocked (DBusPendingCall *pending)
281 _dbus_assert (pending != NULL);
283 return pending->timeout;
287 * Gets the reply's serial number
289 * @param pending the pending_call
290 * @returns a serial number for the reply or 0
293 _dbus_pending_call_get_reply_serial_unlocked (DBusPendingCall *pending)
295 _dbus_assert (pending != NULL);
297 return pending->reply_serial;
301 * Sets the reply's serial number
303 * @param pending the pending_call
304 * @param serial the serial number
307 _dbus_pending_call_set_reply_serial_unlocked (DBusPendingCall *pending,
308 dbus_uint32_t serial)
310 _dbus_assert (pending != NULL);
311 _dbus_assert (pending->reply_serial == 0);
313 pending->reply_serial = serial;
317 * Gets the connection associated with this pending call.
319 * @param pending the pending_call
320 * @returns the connection associated with the pending call
323 _dbus_pending_call_get_connection_and_lock (DBusPendingCall *pending)
325 _dbus_assert (pending != NULL);
327 CONNECTION_LOCK (pending->connection);
328 return pending->connection;
332 * Gets the connection associated with this pending call.
334 * @param pending the pending_call
335 * @returns the connection associated with the pending call
338 _dbus_pending_call_get_connection_unlocked (DBusPendingCall *pending)
340 _dbus_assert (pending != NULL);
342 return pending->connection;
346 * Sets the reply message associated with the pending call to a timeout error
348 * @param pending the pending_call
349 * @param message the message we are sending the error reply to
350 * @param serial serial number for the reply
351 * @return #FALSE on OOM
354 _dbus_pending_call_set_timeout_error_unlocked (DBusPendingCall *pending,
355 DBusMessage *message,
356 dbus_uint32_t serial)
358 DBusList *reply_link;
361 reply = dbus_message_new_error (message, DBUS_ERROR_NO_REPLY,
362 "Did not receive a reply. Possible causes include: "
363 "the remote application did not send a reply, "
364 "the message bus security policy blocked the reply, "
365 "the reply timeout expired, or "
366 "the network connection was broken.");
370 reply_link = _dbus_list_alloc_link (reply);
371 if (reply_link == NULL)
373 /* it's OK to unref this, nothing that could have attached a callback
374 * has ever seen it */
375 dbus_message_unref (reply);
379 pending->timeout_link = reply_link;
381 _dbus_pending_call_set_reply_serial_unlocked (pending, serial);
387 * Increments the reference count on a pending call,
388 * while the lock on its connection is already held.
390 * @param pending the pending call object
391 * @returns the pending call object
394 _dbus_pending_call_ref_unlocked (DBusPendingCall *pending)
396 dbus_int32_t old_refcount;
398 old_refcount = _dbus_atomic_inc (&pending->refcount);
399 _dbus_pending_call_trace_ref (pending, old_refcount, old_refcount + 1,
407 _dbus_pending_call_last_unref (DBusPendingCall *pending)
409 DBusConnection *connection;
411 /* If we get here, we should be already detached
412 * from the connection, or never attached.
414 _dbus_assert (!pending->timeout_added);
416 connection = pending->connection;
418 /* this assumes we aren't holding connection lock... */
419 _dbus_data_slot_list_free (&pending->slot_list);
421 if (pending->timeout != NULL)
422 _dbus_timeout_unref (pending->timeout);
424 if (pending->timeout_link)
426 dbus_message_unref ((DBusMessage *)pending->timeout_link->data);
427 _dbus_list_free_link (pending->timeout_link);
428 pending->timeout_link = NULL;
433 dbus_message_unref (pending->reply);
434 pending->reply = NULL;
439 dbus_pending_call_free_data_slot (¬ify_user_data_slot);
441 /* connection lock should not be held. */
442 /* Free the connection last to avoid a weird state while
443 * calling out to application code where the pending exists
444 * but not the connection.
446 dbus_connection_unref (connection);
450 * Decrements the reference count on a pending call,
451 * freeing it if the count reaches 0. Assumes
452 * connection lock is already held.
454 * @param pending the pending call object
457 _dbus_pending_call_unref_and_unlock (DBusPendingCall *pending)
459 dbus_int32_t old_refcount;
461 old_refcount = _dbus_atomic_dec (&pending->refcount);
462 _dbus_assert (old_refcount > 0);
463 _dbus_pending_call_trace_ref (pending, old_refcount,
464 old_refcount - 1, "unref_and_unlock");
466 CONNECTION_UNLOCK (pending->connection);
468 if (old_refcount == 1)
469 _dbus_pending_call_last_unref (pending);
473 * Checks whether the pending call has received a reply
474 * yet, or not. Assumes connection lock is held.
476 * @param pending the pending call
477 * @returns #TRUE if a reply has been received
480 _dbus_pending_call_get_completed_unlocked (DBusPendingCall *pending)
482 return pending->completed;
485 static DBusDataSlotAllocator slot_allocator =
486 _DBUS_DATA_SLOT_ALLOCATOR_INIT (_DBUS_LOCK_NAME (pending_call_slots));
489 * Stores a pointer on a #DBusPendingCall, along
490 * with an optional function to be used for freeing
491 * the data when the data is set again, or when
492 * the pending call is finalized. The slot number
493 * must have been allocated with dbus_pending_call_allocate_data_slot().
495 * @param pending the pending_call
496 * @param slot the slot number
497 * @param data the data to store
498 * @param free_data_func finalizer function for the data
499 * @returns #TRUE if there was enough memory to store the data
502 _dbus_pending_call_set_data_unlocked (DBusPendingCall *pending,
505 DBusFreeFunction free_data_func)
507 DBusFreeFunction old_free_func;
511 retval = _dbus_data_slot_list_set (&slot_allocator,
513 slot, data, free_data_func,
514 &old_free_func, &old_data);
516 /* Drop locks to call out to app code */
517 CONNECTION_UNLOCK (pending->connection);
522 (* old_free_func) (old_data);
525 CONNECTION_LOCK (pending->connection);
533 * @defgroup DBusPendingCall DBusPendingCall
535 * @brief Pending reply to a method call message
537 * A DBusPendingCall is an object representing an
538 * expected reply. A #DBusPendingCall can be created
539 * when you send a message that should have a reply.
545 * @def DBUS_TIMEOUT_INFINITE
547 * An integer constant representing an infinite timeout. This has the
548 * numeric value 0x7fffffff (the largest 32-bit signed integer).
550 * For source compatibility with D-Bus versions earlier than 1.4.12, use
551 * 0x7fffffff, or INT32_MAX (assuming your platform has it).
555 * @def DBUS_TIMEOUT_USE_DEFAULT
557 * An integer constant representing a request to use the default timeout.
558 * This has numeric value -1.
560 * For source compatibility with D-Bus versions earlier than 1.4.12, use a
565 * @typedef DBusPendingCall
567 * Opaque data type representing a message pending.
571 * Increments the reference count on a pending call.
573 * @param pending the pending call object
574 * @returns the pending call object
577 dbus_pending_call_ref (DBusPendingCall *pending)
579 dbus_int32_t old_refcount;
581 _dbus_return_val_if_fail (pending != NULL, NULL);
583 old_refcount = _dbus_atomic_inc (&pending->refcount);
584 _dbus_pending_call_trace_ref (pending, old_refcount, old_refcount + 1,
591 * Decrements the reference count on a pending call,
592 * freeing it if the count reaches 0.
594 * @param pending the pending call object
597 dbus_pending_call_unref (DBusPendingCall *pending)
599 dbus_int32_t old_refcount;
601 _dbus_return_if_fail (pending != NULL);
603 old_refcount = _dbus_atomic_dec (&pending->refcount);
604 _dbus_pending_call_trace_ref (pending, old_refcount, old_refcount - 1,
607 if (old_refcount == 1)
608 _dbus_pending_call_last_unref(pending);
612 * Sets a notification function to be called when the reply is
613 * received or the pending call times out.
615 * @param pending the pending call
616 * @param function notifier function
617 * @param user_data data to pass to notifier function
618 * @param free_user_data function to free the user data
619 * @returns #FALSE if not enough memory
622 dbus_pending_call_set_notify (DBusPendingCall *pending,
623 DBusPendingCallNotifyFunction function,
625 DBusFreeFunction free_user_data)
627 dbus_bool_t ret = FALSE;
629 _dbus_return_val_if_fail (pending != NULL, FALSE);
631 CONNECTION_LOCK (pending->connection);
633 /* could invoke application code! */
634 if (!_dbus_pending_call_set_data_unlocked (pending, notify_user_data_slot,
635 user_data, free_user_data))
638 pending->function = function;
642 CONNECTION_UNLOCK (pending->connection);
648 * Cancels the pending call, such that any reply or error received
649 * will just be ignored. Drops the dbus library's internal reference
650 * to the #DBusPendingCall so will free the call if nobody else is
651 * holding a reference. However you usually get a reference from
652 * dbus_connection_send_with_reply() so probably your app owns a ref
655 * Note that canceling a pending call will <em>not</em> simulate a
656 * timed-out call; if a call times out, then a timeout error reply is
657 * received. If you cancel the call, no reply is received unless the
658 * the reply was already received before you canceled.
660 * @param pending the pending call
663 dbus_pending_call_cancel (DBusPendingCall *pending)
665 _dbus_return_if_fail (pending != NULL);
667 _dbus_connection_remove_pending_call (pending->connection,
672 * Checks whether the pending call has received a reply
675 * @param pending the pending call
676 * @returns #TRUE if a reply has been received
679 dbus_pending_call_get_completed (DBusPendingCall *pending)
681 dbus_bool_t completed;
683 _dbus_return_val_if_fail (pending != NULL, FALSE);
685 CONNECTION_LOCK (pending->connection);
686 completed = pending->completed;
687 CONNECTION_UNLOCK (pending->connection);
693 * Gets the reply, or returns #NULL if none has been received
694 * yet. Ownership of the reply message passes to the caller. This
695 * function can only be called once per pending call, since the reply
696 * message is tranferred to the caller.
698 * @param pending the pending call
699 * @returns the reply message or #NULL.
702 dbus_pending_call_steal_reply (DBusPendingCall *pending)
704 DBusMessage *message;
706 _dbus_return_val_if_fail (pending != NULL, NULL);
707 _dbus_return_val_if_fail (pending->completed, NULL);
708 _dbus_return_val_if_fail (pending->reply != NULL, NULL);
710 CONNECTION_LOCK (pending->connection);
712 message = pending->reply;
713 pending->reply = NULL;
715 CONNECTION_UNLOCK (pending->connection);
717 _dbus_message_trace_ref (message, -1, -1, "dbus_pending_call_steal_reply");
722 * Block until the pending call is completed. The blocking is as with
723 * dbus_connection_send_with_reply_and_block(); it does not enter the
724 * main loop or process other messages, it simply waits for the reply
727 * If the pending call is already completed, this function returns
730 * @todo when you start blocking, the timeout is reset, but it should
731 * really only use time remaining since the pending call was created.
732 * This requires storing timestamps instead of intervals in the timeout
734 * @param pending the pending call
737 dbus_pending_call_block (DBusPendingCall *pending)
739 _dbus_return_if_fail (pending != NULL);
741 _dbus_connection_block_pending_call (pending);
745 * Allocates an integer ID to be used for storing application-specific
746 * data on any DBusPendingCall. The allocated ID may then be used
747 * with dbus_pending_call_set_data() and dbus_pending_call_get_data().
748 * The passed-in slot must be initialized to -1, and is filled in
749 * with the slot ID. If the passed-in slot is not -1, it's assumed
750 * to be already allocated, and its refcount is incremented.
752 * The allocated slot is global, i.e. all DBusPendingCall objects will
753 * have a slot with the given integer ID reserved.
755 * @param slot_p address of a global variable storing the slot
756 * @returns #FALSE on failure (no memory)
759 dbus_pending_call_allocate_data_slot (dbus_int32_t *slot_p)
761 _dbus_return_val_if_fail (slot_p != NULL, FALSE);
763 return _dbus_data_slot_allocator_alloc (&slot_allocator,
768 * Deallocates a global ID for #DBusPendingCall data slots.
769 * dbus_pending_call_get_data() and dbus_pending_call_set_data() may
770 * no longer be used with this slot. Existing data stored on existing
771 * DBusPendingCall objects will be freed when the #DBusPendingCall is
772 * finalized, but may not be retrieved (and may only be replaced if
773 * someone else reallocates the slot). When the refcount on the
774 * passed-in slot reaches 0, it is set to -1.
776 * @param slot_p address storing the slot to deallocate
779 dbus_pending_call_free_data_slot (dbus_int32_t *slot_p)
781 _dbus_return_if_fail (slot_p != NULL);
782 _dbus_return_if_fail (*slot_p >= 0);
784 _dbus_data_slot_allocator_free (&slot_allocator, slot_p);
788 * Stores a pointer on a #DBusPendingCall, along
789 * with an optional function to be used for freeing
790 * the data when the data is set again, or when
791 * the pending call is finalized. The slot number
792 * must have been allocated with dbus_pending_call_allocate_data_slot().
794 * @param pending the pending_call
795 * @param slot the slot number
796 * @param data the data to store
797 * @param free_data_func finalizer function for the data
798 * @returns #TRUE if there was enough memory to store the data
801 dbus_pending_call_set_data (DBusPendingCall *pending,
804 DBusFreeFunction free_data_func)
808 _dbus_return_val_if_fail (pending != NULL, FALSE);
809 _dbus_return_val_if_fail (slot >= 0, FALSE);
812 CONNECTION_LOCK (pending->connection);
813 retval = _dbus_pending_call_set_data_unlocked (pending, slot, data, free_data_func);
814 CONNECTION_UNLOCK (pending->connection);
819 * Retrieves data previously set with dbus_pending_call_set_data().
820 * The slot must still be allocated (must not have been freed).
822 * @param pending the pending_call
823 * @param slot the slot to get data from
824 * @returns the data, or #NULL if not found
827 dbus_pending_call_get_data (DBusPendingCall *pending,
832 _dbus_return_val_if_fail (pending != NULL, NULL);
834 CONNECTION_LOCK (pending->connection);
835 res = _dbus_data_slot_list_get (&slot_allocator,
838 CONNECTION_UNLOCK (pending->connection);