/* -*- mode: C; c-file-style: "gnu" -*- */
/* dbus-mainloop.c Main loop utility
*
* Copyright (C) 2003, 2004 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-mainloop.h"
#ifndef DOXYGEN_SHOULD_SKIP_THIS
#include <dbus/dbus-list.h>
#include <dbus/dbus-sysdeps.h>
#define MAINLOOP_SPEW 0
#if MAINLOOP_SPEW
#ifdef DBUS_ENABLE_VERBOSE_MODE
static const char*
watch_flags_to_string (int flags)
{
const char *watch_type;
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";
return watch_type;
}
#endif /* DBUS_ENABLE_VERBOSE_MODE */
#endif /* MAINLOOP_SPEW */
struct DBusLoop
{
int refcount;
DBusList *callbacks;
int callback_list_serial;
int watch_count;
int timeout_count;
int depth; /**< number of recursive runs */
DBusList *need_dispatch;
};
typedef enum
{
CALLBACK_WATCH,
CALLBACK_TIMEOUT
} CallbackType;
typedef struct
{
int refcount;
CallbackType type;
void *data;
DBusFreeFunction free_data_func;
} Callback;
typedef struct
{
Callback callback;
DBusWatchFunction function;
DBusWatch *watch;
/* last watch handle failed due to OOM */
unsigned int last_iteration_oom : 1;
} WatchCallback;
typedef struct
{
Callback callback;
DBusTimeout *timeout;
DBusTimeoutFunction function;
unsigned long last_tv_sec;
unsigned long last_tv_usec;
} TimeoutCallback;
#define WATCH_CALLBACK(callback) ((WatchCallback*)callback)
#define TIMEOUT_CALLBACK(callback) ((TimeoutCallback*)callback)
static WatchCallback*
watch_callback_new (DBusWatch *watch,
DBusWatchFunction function,
void *data,
DBusFreeFunction free_data_func)
{
WatchCallback *cb;
cb = dbus_new (WatchCallback, 1);
if (cb == NULL)
return NULL;
cb->watch = watch;
cb->function = function;
cb->last_iteration_oom = FALSE;
cb->callback.refcount = 1;
cb->callback.type = CALLBACK_WATCH;
cb->callback.data = data;
cb->callback.free_data_func = free_data_func;
return cb;
}
static TimeoutCallback*
timeout_callback_new (DBusTimeout *timeout,
DBusTimeoutFunction function,
void *data,
DBusFreeFunction free_data_func)
{
TimeoutCallback *cb;
cb = dbus_new (TimeoutCallback, 1);
if (cb == NULL)
return NULL;
cb->timeout = timeout;
cb->function = function;
_dbus_get_current_time (&cb->last_tv_sec,
&cb->last_tv_usec);
cb->callback.refcount = 1;
cb->callback.type = CALLBACK_TIMEOUT;
cb->callback.data = data;
cb->callback.free_data_func = free_data_func;
return cb;
}
static Callback *
callback_ref (Callback *cb)
{
_dbus_assert (cb->refcount > 0);
cb->refcount += 1;
return cb;
}
static void
callback_unref (Callback *cb)
{
_dbus_assert (cb->refcount > 0);
cb->refcount -= 1;
if (cb->refcount == 0)
{
if (cb->free_data_func)
(* cb->free_data_func) (cb->data);
dbus_free (cb);
}
}
static dbus_bool_t
add_callback (DBusLoop *loop,
Callback *cb)
{
if (!_dbus_list_append (&loop->callbacks, cb))
return FALSE;
loop->callback_list_serial += 1;
switch (cb->type)
{
case CALLBACK_WATCH:
loop->watch_count += 1;
break;
case CALLBACK_TIMEOUT:
loop->timeout_count += 1;
break;
}
return TRUE;
}
static void
remove_callback (DBusLoop *loop,
DBusList *link)
{
Callback *cb = link->data;
switch (cb->type)
{
case CALLBACK_WATCH:
loop->watch_count -= 1;
break;
case CALLBACK_TIMEOUT:
loop->timeout_count -= 1;
break;
}
callback_unref (cb);
_dbus_list_remove_link (&loop->callbacks, link);
loop->callback_list_serial += 1;
}
DBusLoop*
_dbus_loop_new (void)
{
DBusLoop *loop;
loop = dbus_new0 (DBusLoop, 1);
if (loop == NULL)
return NULL;
loop->refcount = 1;
return loop;
}
DBusLoop *
_dbus_loop_ref (DBusLoop *loop)
{
_dbus_assert (loop != NULL);
_dbus_assert (loop->refcount > 0);
loop->refcount += 1;
return loop;
}
void
_dbus_loop_unref (DBusLoop *loop)
{
_dbus_assert (loop != NULL);
_dbus_assert (loop->refcount > 0);
loop->refcount -= 1;
if (loop->refcount == 0)
{
while (loop->need_dispatch)
{
DBusConnection *connection = _dbus_list_pop_first (&loop->need_dispatch);
dbus_connection_unref (connection);
}
dbus_free (loop);
}
}
dbus_bool_t
_dbus_loop_add_watch (DBusLoop *loop,
DBusWatch *watch,
DBusWatchFunction function,
void *data,
DBusFreeFunction free_data_func)
{
WatchCallback *wcb;
wcb = watch_callback_new (watch, function, data, free_data_func);
if (wcb == NULL)
return FALSE;
if (!add_callback (loop, (Callback*) wcb))
{
wcb->callback.free_data_func = NULL; /* don't want to have this side effect */
callback_unref ((Callback*) wcb);
return FALSE;
}
return TRUE;
}
void
_dbus_loop_remove_watch (DBusLoop *loop,
DBusWatch *watch,
DBusWatchFunction function,
void *data)
{
DBusList *link;
link = _dbus_list_get_first_link (&loop->callbacks);
while (link != NULL)
{
DBusList *next = _dbus_list_get_next_link (&loop->callbacks, link);
Callback *this = link->data;
if (this->type == CALLBACK_WATCH &&
WATCH_CALLBACK (this)->watch == watch &&
this->data == data &&
WATCH_CALLBACK (this)->function == function)
{
remove_callback (loop, link);
return;
}
link = next;
}
_dbus_warn ("could not find watch %p function %p data %p to remove\n",
watch, (void *)function, data);
}
dbus_bool_t
_dbus_loop_add_timeout (DBusLoop *loop,
DBusTimeout *timeout,
DBusTimeoutFunction function,
void *data,
DBusFreeFunction free_data_func)
{
TimeoutCallback *tcb;
tcb = timeout_callback_new (timeout, function, data, free_data_func);
if (tcb == NULL)
return FALSE;
if (!add_callback (loop, (Callback*) tcb))
{
tcb->callback.free_data_func = NULL; /* don't want to have this side effect */
callback_unref ((Callback*) tcb);
return FALSE;
}
return TRUE;
}
void
_dbus_loop_remove_timeout (DBusLoop *loop,
DBusTimeout *timeout,
DBusTimeoutFunction function,
void *data)
{
DBusList *link;
link = _dbus_list_get_first_link (&loop->callbacks);
while (link != NULL)
{
DBusList *next = _dbus_list_get_next_link (&loop->callbacks, link);
Callback *this = link->data;
if (this->type == CALLBACK_TIMEOUT &&
TIMEOUT_CALLBACK (this)->timeout == timeout &&
this->data == data &&
TIMEOUT_CALLBACK (this)->function == function)
{
remove_callback (loop, link);
return;
}
link = next;
}
_dbus_warn ("could not find timeout %p function %p data %p to remove\n",
timeout, (void *)function, data);
}
/* Convolutions from GLib, there really must be a better way
* to do this.
*/
static dbus_bool_t
check_timeout (unsigned long tv_sec,
unsigned long tv_usec,
TimeoutCallback *tcb,
int *timeout)
{
long sec_remaining;
long msec_remaining;
unsigned long expiration_tv_sec;
unsigned long expiration_tv_usec;
long interval_seconds;
long interval_milliseconds;
int interval;
/* I'm pretty sure this function could suck (a lot) less */
interval = dbus_timeout_get_interval (tcb->timeout);
interval_seconds = interval / 1000L;
interval_milliseconds = interval % 1000L;
expiration_tv_sec = tcb->last_tv_sec + interval_seconds;
expiration_tv_usec = tcb->last_tv_usec + interval_milliseconds * 1000;
if (expiration_tv_usec >= 1000000)
{
expiration_tv_usec -= 1000000;
expiration_tv_sec += 1;
}
sec_remaining = expiration_tv_sec - tv_sec;
/* need to force this to be signed, as it is intended to sometimes
* produce a negative result
*/
msec_remaining = ((long) expiration_tv_usec - (long) tv_usec) / 1000L;
#if MAINLOOP_SPEW
_dbus_verbose ("Interval is %ld seconds %ld msecs\n",
interval_seconds,
interval_milliseconds);
_dbus_verbose ("Now is %lu seconds %lu usecs\n",
tv_sec, tv_usec);
_dbus_verbose ("Last is %lu seconds %lu usecs\n",
tcb->last_tv_sec, tcb->last_tv_usec);
_dbus_verbose ("Exp is %lu seconds %lu usecs\n",
expiration_tv_sec, expiration_tv_usec);
_dbus_verbose ("Pre-correction, sec_remaining %ld msec_remaining %ld\n",
sec_remaining, msec_remaining);
#endif
/* We do the following in a rather convoluted fashion to deal with
* the fact that we don't have an integral type big enough to hold
* the difference of two timevals in milliseconds.
*/
if (sec_remaining < 0 || (sec_remaining == 0 && msec_remaining < 0))
{
*timeout = 0;
}
else
{
if (msec_remaining < 0)
{
msec_remaining += 1000;
sec_remaining -= 1;
}
if (sec_remaining > (_DBUS_INT_MAX / 1000) ||
msec_remaining > _DBUS_INT_MAX)
*timeout = _DBUS_INT_MAX;
else
*timeout = sec_remaining * 1000 + msec_remaining;
}
if (*timeout > interval)
{
/* This indicates that the system clock probably moved backward */
_dbus_verbose ("System clock set backward! Resetting timeout.\n");
tcb->last_tv_sec = tv_sec;
tcb->last_tv_usec = tv_usec;
*timeout = interval;
}
#if MAINLOOP_SPEW
_dbus_verbose (" timeout expires in %d milliseconds\n", *timeout);
#endif
return *timeout == 0;
}
dbus_bool_t
_dbus_loop_dispatch (DBusLoop *loop)
{
#if MAINLOOP_SPEW
_dbus_verbose (" %d connections to dispatch\n", _dbus_list_get_length (&loop->need_dispatch));
#endif
if (loop->need_dispatch == NULL)
return FALSE;
next:
while (loop->need_dispatch != NULL)
{
DBusConnection *connection = _dbus_list_pop_first (&loop->need_dispatch);
while (TRUE)
{
DBusDispatchStatus status;
status = dbus_connection_dispatch (connection);
if (status == DBUS_DISPATCH_COMPLETE)
{
dbus_connection_unref (connection);
goto next;
}
else
{
if (status == DBUS_DISPATCH_NEED_MEMORY)
_dbus_wait_for_memory ();
}
}
}
return TRUE;
}
dbus_bool_t
_dbus_loop_queue_dispatch (DBusLoop *loop,
DBusConnection *connection)
{
if (_dbus_list_append (&loop->need_dispatch, connection))
{
dbus_connection_ref (connection);
return TRUE;
}
else
return FALSE;
}
/* Returns TRUE if we invoked any timeouts or have ready file
* descriptors, which is just used in test code as a debug hack
*/
dbus_bool_t
_dbus_loop_iterate (DBusLoop *loop,
dbus_bool_t block)
{
#define N_STACK_DESCRIPTORS 64
dbus_bool_t retval;
DBusPollFD *fds;
DBusPollFD stack_fds[N_STACK_DESCRIPTORS];
int n_fds;
WatchCallback **watches_for_fds;
WatchCallback *stack_watches_for_fds[N_STACK_DESCRIPTORS];
int i;
DBusList *link;
int n_ready;
int initial_serial;
long timeout;
dbus_bool_t oom_watch_pending;
int orig_depth;
retval = FALSE;
fds = NULL;
watches_for_fds = NULL;
n_fds = 0;
oom_watch_pending = FALSE;
orig_depth = loop->depth;
#if MAINLOOP_SPEW
_dbus_verbose ("Iteration block=%d depth=%d timeout_count=%d watch_count=%d\n",
block, loop->depth, loop->timeout_count, loop->watch_count);
#endif
if (loop->callbacks == NULL)
goto next_iteration;
if (loop->watch_count > N_STACK_DESCRIPTORS)
{
fds = dbus_new0 (DBusPollFD, loop->watch_count);
while (fds == NULL)
{
_dbus_wait_for_memory ();
fds = dbus_new0 (DBusPollFD, loop->watch_count);
}
watches_for_fds = dbus_new (WatchCallback*, loop->watch_count);
while (watches_for_fds == NULL)
{
_dbus_wait_for_memory ();
watches_for_fds = dbus_new (WatchCallback*, loop->watch_count);
}
}
else
{
fds = stack_fds;
watches_for_fds = stack_watches_for_fds;
}
/* fill our array of fds and watches */
n_fds = 0;
link = _dbus_list_get_first_link (&loop->callbacks);
while (link != NULL)
{
DBusList *next = _dbus_list_get_next_link (&loop->callbacks, link);
Callback *cb = link->data;
if (cb->type == CALLBACK_WATCH)
{
unsigned int flags;
WatchCallback *wcb = WATCH_CALLBACK (cb);
if (wcb->last_iteration_oom)
{
/* we skip this one this time, but reenable it next time,
* and have a timeout on this iteration
*/
wcb->last_iteration_oom = FALSE;
oom_watch_pending = TRUE;
retval = TRUE; /* return TRUE here to keep the loop going,
* since we don't know the watch is inactive
*/
#if MAINLOOP_SPEW
_dbus_verbose (" skipping watch on fd %d as it was out of memory last time\n",
dbus_watch_get_fd (wcb->watch));
#endif
}
else if (dbus_watch_get_enabled (wcb->watch))
{
watches_for_fds[n_fds] = wcb;
callback_ref (cb);
flags = dbus_watch_get_flags (wcb->watch);
fds[n_fds].fd = dbus_watch_get_fd (wcb->watch);
fds[n_fds].revents = 0;
fds[n_fds].events = 0;
if (flags & DBUS_WATCH_READABLE)
fds[n_fds].events |= _DBUS_POLLIN;
if (flags & DBUS_WATCH_WRITABLE)
fds[n_fds].events |= _DBUS_POLLOUT;
#if MAINLOOP_SPEW
_dbus_verbose (" polling watch on fd %d %s\n",
fds[n_fds].fd, watch_flags_to_string (flags));
#endif
n_fds += 1;
}
else
{
#if MAINLOOP_SPEW
_dbus_verbose (" skipping disabled watch on fd %d %s\n",
dbus_watch_get_fd (wcb->watch),
watch_flags_to_string (dbus_watch_get_flags (wcb->watch)));
#endif
}
}
link = next;
}
timeout = -1;
if (loop->timeout_count > 0)
{
unsigned long tv_sec;
unsigned long tv_usec;
_dbus_get_current_time (&tv_sec, &tv_usec);
link = _dbus_list_get_first_link (&loop->callbacks);
while (link != NULL)
{
DBusList *next = _dbus_list_get_next_link (&loop->callbacks, link);
Callback *cb = link->data;
if (cb->type == CALLBACK_TIMEOUT &&
dbus_timeout_get_enabled (TIMEOUT_CALLBACK (cb)->timeout))
{
TimeoutCallback *tcb = TIMEOUT_CALLBACK (cb);
int msecs_remaining;
check_timeout (tv_sec, tv_usec, tcb, &msecs_remaining);
if (timeout < 0)
timeout = msecs_remaining;
else
timeout = MIN (msecs_remaining, timeout);
#if MAINLOOP_SPEW
_dbus_verbose (" timeout added, %d remaining, aggregate timeout %ld\n",
msecs_remaining, timeout);
#endif
_dbus_assert (timeout >= 0);
if (timeout == 0)
break; /* it's not going to get shorter... */
}
#if MAINLOOP_SPEW
else if (cb->type == CALLBACK_TIMEOUT)
{
_dbus_verbose (" skipping disabled timeout\n");
}
#endif
link = next;
}
}
/* Never block if we have stuff to dispatch */
if (!block || loop->need_dispatch != NULL)
{
timeout = 0;
#if MAINLOOP_SPEW
_dbus_verbose (" timeout is 0 as we aren't blocking\n");
#endif
}
/* if a watch is OOM, don't wait longer than the OOM
* wait to re-enable it
*/
if (oom_watch_pending)
timeout = MIN (timeout, _dbus_get_oom_wait ());
#if MAINLOOP_SPEW
_dbus_verbose (" polling on %d descriptors timeout %ld\n", n_fds, timeout);
#endif
n_ready = _dbus_poll (fds, n_fds, timeout);
initial_serial = loop->callback_list_serial;
if (loop->timeout_count > 0)
{
unsigned long tv_sec;
unsigned long tv_usec;
_dbus_get_current_time (&tv_sec, &tv_usec);
/* It'd be nice to avoid this O(n) thingy here */
link = _dbus_list_get_first_link (&loop->callbacks);
while (link != NULL)
{
DBusList *next = _dbus_list_get_next_link (&loop->callbacks, link);
Callback *cb = link->data;
if (initial_serial != loop->callback_list_serial)
goto next_iteration;
if (loop->depth != orig_depth)
goto next_iteration;
if (cb->type == CALLBACK_TIMEOUT &&
dbus_timeout_get_enabled (TIMEOUT_CALLBACK (cb)->timeout))
{
TimeoutCallback *tcb = TIMEOUT_CALLBACK (cb);
int msecs_remaining;
if (check_timeout (tv_sec, tv_usec,
tcb, &msecs_remaining))
{
/* Save last callback time and fire this timeout */
tcb->last_tv_sec = tv_sec;
tcb->last_tv_usec = tv_usec;
#if MAINLOOP_SPEW
_dbus_verbose (" invoking timeout\n");
#endif
(* tcb->function) (tcb->timeout,
cb->data);
retval = TRUE;
}
else
{
#if MAINLOOP_SPEW
_dbus_verbose (" timeout has not expired\n");
#endif
}
}
#if MAINLOOP_SPEW
else if (cb->type == CALLBACK_TIMEOUT)
{
_dbus_verbose (" skipping invocation of disabled timeout\n");
}
#endif
link = next;
}
}
if (n_ready > 0)
{
i = 0;
while (i < n_fds)
{
/* FIXME I think this "restart if we change the watches"
* approach could result in starving watches
* toward the end of the list.
*/
if (initial_serial != loop->callback_list_serial)
goto next_iteration;
if (loop->depth != orig_depth)
goto next_iteration;
if (fds[i].revents != 0)
{
WatchCallback *wcb;
unsigned int condition;
wcb = watches_for_fds[i];
condition = 0;
if (fds[i].revents & _DBUS_POLLIN)
condition |= DBUS_WATCH_READABLE;
if (fds[i].revents & _DBUS_POLLOUT)
condition |= DBUS_WATCH_WRITABLE;
if (fds[i].revents & _DBUS_POLLHUP)
condition |= DBUS_WATCH_HANGUP;
if (fds[i].revents & _DBUS_POLLERR)
condition |= DBUS_WATCH_ERROR;
/* condition may still be 0 if we got some
* weird POLLFOO thing like POLLWRBAND
*/
if (condition != 0 &&
dbus_watch_get_enabled (wcb->watch))
{
if (!(* wcb->function) (wcb->watch,
condition,
((Callback*)wcb)->data))
wcb->last_iteration_oom = TRUE;
#if MAINLOOP_SPEW
_dbus_verbose (" Invoked watch, oom = %d\n",
wcb->last_iteration_oom);
#endif
retval = TRUE;
}
}
++i;
}
}
next_iteration:
#if MAINLOOP_SPEW
_dbus_verbose (" moving to next iteration\n");
#endif
if (fds && fds != stack_fds)
dbus_free (fds);
if (watches_for_fds)
{
i = 0;
while (i < n_fds)
{
callback_unref (&watches_for_fds[i]->callback);
++i;
}
if (watches_for_fds != stack_watches_for_fds)
dbus_free (watches_for_fds);
}
if (_dbus_loop_dispatch (loop))
retval = TRUE;
#if MAINLOOP_SPEW
_dbus_verbose ("Returning %d\n", retval);
#endif
return retval;
}
void
_dbus_loop_run (DBusLoop *loop)
{
int our_exit_depth;
_dbus_assert (loop->depth >= 0);
_dbus_loop_ref (loop);
our_exit_depth = loop->depth;
loop->depth += 1;
_dbus_verbose ("Running main loop, depth %d -> %d\n",
loop->depth - 1, loop->depth);
while (loop->depth != our_exit_depth)
_dbus_loop_iterate (loop, TRUE);
_dbus_loop_unref (loop);
}
void
_dbus_loop_quit (DBusLoop *loop)
{
_dbus_assert (loop->depth > 0);
loop->depth -= 1;
_dbus_verbose ("Quit main loop, depth %d -> %d\n",
loop->depth + 1, loop->depth);
}
int
_dbus_get_oom_wait (void)
{
#ifdef DBUS_BUILD_TESTS
/* make tests go fast */
return 0;
#else
return 500;
#endif
}
void
_dbus_wait_for_memory (void)
{
_dbus_verbose ("Waiting for more memory\n");
_dbus_sleep_milliseconds (_dbus_get_oom_wait ());
}
#endif /* !DOXYGEN_SHOULD_SKIP_THIS */