/* -*- mode: C; c-file-style: "gnu" -*- */
/* dbus-pending-call.c Object representing a call in progress.
*
* Copyright (C) 2002, 2003 Red Hat Inc.
*
* 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-connection-internal.h"
#include "dbus-pending-call-internal.h"
#include "dbus-pending-call.h"
#include "dbus-list.h"
#include "dbus-threads.h"
#include "dbus-test.h"
/**
* @defgroup DBusPendingCallInternals DBusPendingCall implementation details
* @ingroup DBusInternals
* @brief DBusPendingCall private implementation details.
*
* The guts of DBusPendingCall and its methods.
*
* @{
*/
/**
* @brief Internals of DBusPendingCall
*
* Opaque object representing a reply message that we're waiting for.
*/
/**
* shorter and more visible way to write _dbus_connection_lock()
*/
#define CONNECTION_LOCK(connection) _dbus_connection_lock(connection)
/**
* shorter and more visible way to write _dbus_connection_unlock()
*/
#define CONNECTION_UNLOCK(connection) _dbus_connection_unlock(connection)
/**
* Implementation details of #DBusPendingCall - all fields are private.
*/
struct DBusPendingCall
{
DBusAtomic refcount; /**< reference count */
DBusDataSlotList slot_list; /**< Data stored by allocated integer ID */
DBusPendingCallNotifyFunction function; /**< Notifier when reply arrives. */
DBusConnection *connection; /**< Connections we're associated with */
DBusMessage *reply; /**< Reply (after we've received it) */
DBusTimeout *timeout; /**< Timeout */
DBusList *timeout_link; /**< Preallocated timeout response */
dbus_uint32_t reply_serial; /**< Expected serial of reply */
unsigned int completed : 1; /**< TRUE if completed */
unsigned int timeout_added : 1; /**< Have added the timeout */
};
static dbus_int32_t notify_user_data_slot = -1;
/**
* Creates a new pending reply object.
*
* @param connection connection where reply will arrive
* @param timeout_milliseconds length of timeout, -1 for default
* @param timeout_handler timeout handler, takes pending call as data
* @returns a new #DBusPendingCall or #NULL if no memory.
*/
DBusPendingCall*
_dbus_pending_call_new_unlocked (DBusConnection *connection,
int timeout_milliseconds,
DBusTimeoutHandler timeout_handler)
{
DBusPendingCall *pending;
DBusTimeout *timeout;
_dbus_assert (timeout_milliseconds >= 0 || timeout_milliseconds == -1);
if (timeout_milliseconds == -1)
timeout_milliseconds = _DBUS_DEFAULT_TIMEOUT_VALUE;
/* it would probably seem logical to pass in _DBUS_INT_MAX for
* infinite timeout, but then math in
* _dbus_connection_block_for_reply would get all overflow-prone, so
* smack that down.
*/
if (timeout_milliseconds > _DBUS_ONE_HOUR_IN_MILLISECONDS * 6)
timeout_milliseconds = _DBUS_ONE_HOUR_IN_MILLISECONDS * 6;
if (!dbus_pending_call_allocate_data_slot (¬ify_user_data_slot))
return NULL;
pending = dbus_new0 (DBusPendingCall, 1);
if (pending == NULL)
{
dbus_pending_call_free_data_slot (¬ify_user_data_slot);
return NULL;
}
timeout = _dbus_timeout_new (timeout_milliseconds,
timeout_handler,
pending, NULL);
if (timeout == NULL)
{
dbus_pending_call_free_data_slot (¬ify_user_data_slot);
dbus_free (pending);
return NULL;
}
pending->refcount.value = 1;
pending->connection = connection;
_dbus_connection_ref_unlocked (pending->connection);
pending->timeout = timeout;
_dbus_data_slot_list_init (&pending->slot_list);
return pending;
}
/**
* Sets the reply of a pending call with the given message,
* or if the message is #NULL, by timing out the pending call.
*
* @param pending the pending call
* @param message the message to complete the call with, or #NULL
* to time out the call
*/
void
_dbus_pending_call_set_reply_unlocked (DBusPendingCall *pending,
DBusMessage *message)
{
if (message == NULL)
{
message = pending->timeout_link->data;
_dbus_list_clear (&pending->timeout_link);
}
else
dbus_message_ref (message);
_dbus_verbose (" handing message %p (%s) to pending call serial %u\n",
message,
dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_METHOD_RETURN ?
"method return" :
dbus_message_get_type (message) == DBUS_MESSAGE_TYPE_ERROR ?
"error" : "other type",
pending->reply_serial);
_dbus_assert (pending->reply == NULL);
_dbus_assert (pending->reply_serial == dbus_message_get_reply_serial (message));
pending->reply = message;
}
/**
* Calls notifier function for the pending call
* and sets the call to completed.
*
* @param pending the pending call
*
*/
void
_dbus_pending_call_complete (DBusPendingCall *pending)
{
_dbus_assert (!pending->completed);
pending->completed = TRUE;
if (pending->function)
{
void *user_data;
user_data = dbus_pending_call_get_data (pending,
notify_user_data_slot);
(* pending->function) (pending, user_data);
}
}
/**
* If the pending call hasn't been timed out, add its timeout
* error reply to the connection's incoming message queue.
*
* @param pending the pending call
* @param connection the connection the call was sent to
*/
void
_dbus_pending_call_queue_timeout_error_unlocked (DBusPendingCall *pending,
DBusConnection *connection)
{
_dbus_assert (connection == pending->connection);
if (pending->timeout_link)
{
_dbus_connection_queue_synthesized_message_link (connection,
pending->timeout_link);
pending->timeout_link = NULL;
}
}
/**
* Checks to see if a timeout has been added
*
* @param pending the pending_call
* @returns #TRUE if there is a timeout or #FALSE if not
*/
dbus_bool_t
_dbus_pending_call_is_timeout_added_unlocked (DBusPendingCall *pending)
{
_dbus_assert (pending != NULL);
return pending->timeout_added;
}
/**
* Sets wether the timeout has been added
*
* @param pending the pending_call
* @param is_added whether or not a timeout is added
*/
void
_dbus_pending_call_set_timeout_added_unlocked (DBusPendingCall *pending,
dbus_bool_t is_added)
{
_dbus_assert (pending != NULL);
pending->timeout_added = is_added;
}
/**
* Retrives the timeout
*
* @param pending the pending_call
* @returns a timeout object
*/
DBusTimeout *
_dbus_pending_call_get_timeout_unlocked (DBusPendingCall *pending)
{
_dbus_assert (pending != NULL);
return pending->timeout;
}
/**
* Gets the reply's serial number
*
* @param pending the pending_call
* @returns a serial number for the reply or 0
*/
dbus_uint32_t
_dbus_pending_call_get_reply_serial_unlocked (DBusPendingCall *pending)
{
_dbus_assert (pending != NULL);
return pending->reply_serial;
}
/**
* Sets the reply's serial number
*
* @param pending the pending_call
* @param serial the serial number
*/
void
_dbus_pending_call_set_reply_serial_unlocked (DBusPendingCall *pending,
dbus_uint32_t serial)
{
_dbus_assert (pending != NULL);
_dbus_assert (pending->reply_serial == 0);
pending->reply_serial = serial;
}
/**
* Gets the connection associated with this pending call.
*
* @param pending the pending_call
* @returns the connection associated with the pending call
*/
DBusConnection *
_dbus_pending_call_get_connection_and_lock (DBusPendingCall *pending)
{
_dbus_assert (pending != NULL);
CONNECTION_LOCK (pending->connection);
return pending->connection;
}
/**
* Gets the connection associated with this pending call.
*
* @param pending the pending_call
* @returns the connection associated with the pending call
*/
DBusConnection *
_dbus_pending_call_get_connection_unlocked (DBusPendingCall *pending)
{
_dbus_assert (pending != NULL);
return pending->connection;
}
/**
* Sets the reply message associated with the pending call to a timeout error
*
* @param pending the pending_call
* @param message the message we are sending the error reply to
* @param serial serial number for the reply
* @return #FALSE on OOM
*/
dbus_bool_t
_dbus_pending_call_set_timeout_error_unlocked (DBusPendingCall *pending,
DBusMessage *message,
dbus_uint32_t serial)
{
DBusList *reply_link;
DBusMessage *reply;
reply = dbus_message_new_error (message, DBUS_ERROR_NO_REPLY,
"Did not receive a reply. Possible causes include: "
"the remote application did not send a reply, "
"the message bus security policy blocked the reply, "
"the reply timeout expired, or "
"the network connection was broken.");
if (reply == NULL)
return FALSE;
reply_link = _dbus_list_alloc_link (reply);
if (reply_link == NULL)
{
dbus_message_unref (reply);
return FALSE;
}
pending->timeout_link = reply_link;
_dbus_pending_call_set_reply_serial_unlocked (pending, serial);
return TRUE;
}
/**
* Increments the reference count on a pending call,
* while the lock on its connection is already held.
*
* @param pending the pending call object
* @returns the pending call object
*/
DBusPendingCall *
_dbus_pending_call_ref_unlocked (DBusPendingCall *pending)
{
pending->refcount.value += 1;
return pending;
}
static void
_dbus_pending_call_last_unref (DBusPendingCall *pending)
{
DBusConnection *connection;
/* If we get here, we should be already detached
* from the connection, or never attached.
*/
_dbus_assert (!pending->timeout_added);
connection = pending->connection;
/* this assumes we aren't holding connection lock... */
_dbus_data_slot_list_free (&pending->slot_list);
if (pending->timeout != NULL)
_dbus_timeout_unref (pending->timeout);
if (pending->timeout_link)
{
dbus_message_unref ((DBusMessage *)pending->timeout_link->data);
_dbus_list_free_link (pending->timeout_link);
pending->timeout_link = NULL;
}
if (pending->reply)
{
dbus_message_unref (pending->reply);
pending->reply = NULL;
}
dbus_free (pending);
dbus_pending_call_free_data_slot (¬ify_user_data_slot);
/* connection lock should not be held. */
/* Free the connection last to avoid a weird state while
* calling out to application code where the pending exists
* but not the connection.
*/
dbus_connection_unref (connection);
}
/**
* Decrements the reference count on a pending call,
* freeing it if the count reaches 0. Assumes
* connection lock is already held.
*
* @param pending the pending call object
*/
void
_dbus_pending_call_unref_and_unlock (DBusPendingCall *pending)
{
dbus_bool_t last_unref;
_dbus_assert (pending->refcount.value > 0);
pending->refcount.value -= 1;
last_unref = pending->refcount.value == 0;
CONNECTION_UNLOCK (pending->connection);
if (last_unref)
_dbus_pending_call_last_unref (pending);
}
/**
* Checks whether the pending call has received a reply
* yet, or not. Assumes connection lock is held.
*
* @param pending the pending call
* @returns #TRUE if a reply has been received
*/
dbus_bool_t
_dbus_pending_call_get_completed_unlocked (DBusPendingCall *pending)
{
return pending->completed;
}
static DBusDataSlotAllocator slot_allocator;
_DBUS_DEFINE_GLOBAL_LOCK (pending_call_slots);
/**
* Stores a pointer on a #DBusPendingCall, along
* with an optional function to be used for freeing
* the data when the data is set again, or when
* the pending call is finalized. The slot number
* must have been allocated with dbus_pending_call_allocate_data_slot().
*
* @param pending the pending_call
* @param slot the slot number
* @param data the data to store
* @param free_data_func finalizer function for the data
* @returns #TRUE if there was enough memory to store the data
*/
dbus_bool_t
_dbus_pending_call_set_data_unlocked (DBusPendingCall *pending,
dbus_int32_t slot,
void *data,
DBusFreeFunction free_data_func)
{
DBusFreeFunction old_free_func;
void *old_data;
dbus_bool_t retval;
retval = _dbus_data_slot_list_set (&slot_allocator,
&pending->slot_list,
slot, data, free_data_func,
&old_free_func, &old_data);
/* Drop locks to call out to app code */
CONNECTION_UNLOCK (pending->connection);
if (retval)
{
if (old_free_func)
(* old_free_func) (old_data);
}
CONNECTION_LOCK (pending->connection);
return retval;
}
/** @} */
/**
* @defgroup DBusPendingCall DBusPendingCall
* @ingroup DBus
* @brief Pending reply to a method call message
*
* A DBusPendingCall is an object representing an
* expected reply. A #DBusPendingCall can be created
* when you send a message that should have a reply.
*
* @{
*/
/**
* @typedef DBusPendingCall
*
* Opaque data type representing a message pending.
*/
/**
* Increments the reference count on a pending call.
*
* @param pending the pending call object
* @returns the pending call object
*/
DBusPendingCall *
dbus_pending_call_ref (DBusPendingCall *pending)
{
_dbus_return_val_if_fail (pending != NULL, NULL);
/* The connection lock is better than the global
* lock in the atomic increment fallback
*/
#ifdef DBUS_HAVE_ATOMIC_INT
_dbus_atomic_inc (&pending->refcount);
#else
CONNECTION_LOCK (pending->connection);
_dbus_assert (pending->refcount.value > 0);
pending->refcount.value += 1;
CONNECTION_UNLOCK (pending->connection);
#endif
return pending;
}
/**
* Decrements the reference count on a pending call,
* freeing it if the count reaches 0.
*
* @param pending the pending call object
*/
void
dbus_pending_call_unref (DBusPendingCall *pending)
{
dbus_bool_t last_unref;
_dbus_return_if_fail (pending != NULL);
/* More efficient to use the connection lock instead of atomic
* int fallback if we lack atomic int decrement
*/
#ifdef DBUS_HAVE_ATOMIC_INT
last_unref = (_dbus_atomic_dec (&pending->refcount) == 1);
#else
CONNECTION_LOCK (pending->connection);
_dbus_assert (pending->refcount.value > 0);
pending->refcount.value -= 1;
last_unref = pending->refcount.value == 0;
CONNECTION_UNLOCK (pending->connection);
#endif
if (last_unref)
_dbus_pending_call_last_unref(pending);
}
/**
* Sets a notification function to be called when the reply is
* received or the pending call times out.
*
* @param pending the pending call
* @param function notifier function
* @param user_data data to pass to notifier function
* @param free_user_data function to free the user data
* @returns #FALSE if not enough memory
*/
dbus_bool_t
dbus_pending_call_set_notify (DBusPendingCall *pending,
DBusPendingCallNotifyFunction function,
void *user_data,
DBusFreeFunction free_user_data)
{
_dbus_return_val_if_fail (pending != NULL, FALSE);
CONNECTION_LOCK (pending->connection);
/* could invoke application code! */
if (!_dbus_pending_call_set_data_unlocked (pending, notify_user_data_slot,
user_data, free_user_data))
return FALSE;
pending->function = function;
CONNECTION_UNLOCK (pending->connection);
return TRUE;
}
/**
* Cancels the pending call, such that any reply or error received
* will just be ignored. Drops the dbus library's internal reference
* to the #DBusPendingCall so will free the call if nobody else is
* holding a reference. However you usually get a reference from
* dbus_connection_send_with_reply() so probably your app owns a ref
* also.
*
* Note that canceling a pending call will <em>not</em> simulate a
* timed-out call; if a call times out, then a timeout error reply is
* received. If you cancel the call, no reply is received unless the
* the reply was already received before you canceled.
*
* @param pending the pending call
*/
void
dbus_pending_call_cancel (DBusPendingCall *pending)
{
_dbus_return_if_fail (pending != NULL);
_dbus_connection_remove_pending_call (pending->connection,
pending);
}
/**
* Checks whether the pending call has received a reply
* yet, or not.
*
* @param pending the pending call
* @returns #TRUE if a reply has been received
*/
dbus_bool_t
dbus_pending_call_get_completed (DBusPendingCall *pending)
{
dbus_bool_t completed;
_dbus_return_val_if_fail (pending != NULL, FALSE);
CONNECTION_LOCK (pending->connection);
completed = pending->completed;
CONNECTION_UNLOCK (pending->connection);
return completed;
}
/**
* Gets the reply, or returns #NULL if none has been received
* yet. Ownership of the reply message passes to the caller. This
* function can only be called once per pending call, since the reply
* message is tranferred to the caller.
*
* @param pending the pending call
* @returns the reply message or #NULL.
*/
DBusMessage*
dbus_pending_call_steal_reply (DBusPendingCall *pending)
{
DBusMessage *message;
_dbus_return_val_if_fail (pending != NULL, NULL);
_dbus_return_val_if_fail (pending->completed, NULL);
_dbus_return_val_if_fail (pending->reply != NULL, NULL);
CONNECTION_LOCK (pending->connection);
message = pending->reply;
pending->reply = NULL;
CONNECTION_UNLOCK (pending->connection);
return message;
}
/**
* Block until the pending call is completed. The blocking is as with
* dbus_connection_send_with_reply_and_block(); it does not enter the
* main loop or process other messages, it simply waits for the reply
* in question.
*
* If the pending call is already completed, this function returns
* immediately.
*
* @todo when you start blocking, the timeout is reset, but it should
* really only use time remaining since the pending call was created.
* This requires storing timestamps instead of intervals in the timeout
*
* @param pending the pending call
*/
void
dbus_pending_call_block (DBusPendingCall *pending)
{
_dbus_return_if_fail (pending != NULL);
_dbus_connection_block_pending_call (pending);
}
/**
* Allocates an integer ID to be used for storing application-specific
* data on any DBusPendingCall. The allocated ID may then be used
* with dbus_pending_call_set_data() and dbus_pending_call_get_data().
* The passed-in slot must be initialized to -1, and is filled in
* with the slot ID. If the passed-in slot is not -1, it's assumed
* to be already allocated, and its refcount is incremented.
*
* The allocated slot is global, i.e. all DBusPendingCall objects will
* have a slot with the given integer ID reserved.
*
* @param slot_p address of a global variable storing the slot
* @returns #FALSE on failure (no memory)
*/
dbus_bool_t
dbus_pending_call_allocate_data_slot (dbus_int32_t *slot_p)
{
_dbus_return_val_if_fail (slot_p != NULL, FALSE);
return _dbus_data_slot_allocator_alloc (&slot_allocator,
&_DBUS_LOCK_NAME (pending_call_slots),
slot_p);
}
/**
* Deallocates a global ID for #DBusPendingCall data slots.
* dbus_pending_call_get_data() and dbus_pending_call_set_data() may
* no longer be used with this slot. Existing data stored on existing
* DBusPendingCall objects will be freed when the #DBusPendingCall is
* finalized, but may not be retrieved (and may only be replaced if
* someone else reallocates the slot). When the refcount on the
* passed-in slot reaches 0, it is set to -1.
*
* @param slot_p address storing the slot to deallocate
*/
void
dbus_pending_call_free_data_slot (dbus_int32_t *slot_p)
{
_dbus_return_if_fail (slot_p != NULL);
_dbus_return_if_fail (*slot_p >= 0);
_dbus_data_slot_allocator_free (&slot_allocator, slot_p);
}
/**
* Stores a pointer on a #DBusPendingCall, along
* with an optional function to be used for freeing
* the data when the data is set again, or when
* the pending call is finalized. The slot number
* must have been allocated with dbus_pending_call_allocate_data_slot().
*
* @param pending the pending_call
* @param slot the slot number
* @param data the data to store
* @param free_data_func finalizer function for the data
* @returns #TRUE if there was enough memory to store the data
*/
dbus_bool_t
dbus_pending_call_set_data (DBusPendingCall *pending,
dbus_int32_t slot,
void *data,
DBusFreeFunction free_data_func)
{
dbus_bool_t retval;
_dbus_return_val_if_fail (pending != NULL, FALSE);
_dbus_return_val_if_fail (slot >= 0, FALSE);
CONNECTION_LOCK (pending->connection);
retval = _dbus_pending_call_set_data_unlocked (pending, slot, data, free_data_func);
CONNECTION_UNLOCK (pending->connection);
return retval;
}
/**
* Retrieves data previously set with dbus_pending_call_set_data().
* The slot must still be allocated (must not have been freed).
*
* @param pending the pending_call
* @param slot the slot to get data from
* @returns the data, or #NULL if not found
*/
void*
dbus_pending_call_get_data (DBusPendingCall *pending,
dbus_int32_t slot)
{
void *res;
_dbus_return_val_if_fail (pending != NULL, NULL);
CONNECTION_LOCK (pending->connection);
res = _dbus_data_slot_list_get (&slot_allocator,
&pending->slot_list,
slot);
CONNECTION_UNLOCK (pending->connection);
return res;
}
/** @} */
#ifdef DBUS_BUILD_TESTS
/**
* @ingroup DBusPendingCallInternals
* Unit test for DBusPendingCall.
*
* @returns #TRUE on success.
*/
dbus_bool_t
_dbus_pending_call_test (const char *test_data_dir)
{
return TRUE;
}
#endif /* DBUS_BUILD_TESTS */