--- /dev/null
+/* -*- mode: C; c-file-style: "gnu" -*- */
+/* dbus-mainloop.c Main loop utility
+ *
+ * Copyright (C) 2003 Red Hat, Inc.
+ *
+ * Licensed under the Academic Free License version 1.2
+ *
+ * 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"
+
+#include <dbus/dbus-list.h>
+#include <dbus/dbus-sysdeps.h>
+
+struct DBusLoop
+{
+ int refcount;
+ DBusList *callbacks;
+ int callback_list_serial;
+ int watch_count;
+ int timeout_count;
+ int depth; /**< number of recursive runs */
+};
+
+typedef enum
+{
+ CALLBACK_WATCH,
+ CALLBACK_TIMEOUT
+} CallbackType;
+
+typedef struct
+{
+ 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.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.type = CALLBACK_TIMEOUT;
+ cb->callback.data = data;
+ cb->callback.free_data_func = free_data_func;
+
+ return cb;
+}
+
+static void
+callback_free (Callback *cb)
+{
+ 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_free (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;
+}
+
+void
+_dbus_loop_ref (DBusLoop *loop)
+{
+ _dbus_assert (loop != NULL);
+ _dbus_assert (loop->refcount > 0);
+
+ loop->refcount += 1;
+}
+
+void
+_dbus_loop_unref (DBusLoop *loop)
+{
+ _dbus_assert (loop != NULL);
+ _dbus_assert (loop->refcount > 0);
+
+ loop->refcount -= 1;
+ if (loop->refcount == 0)
+ {
+
+ 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_free ((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, 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_free ((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, 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;
+ long msec;
+ unsigned long expiration_tv_sec;
+ unsigned long expiration_tv_usec;
+ long interval_seconds;
+ long interval_milliseconds;
+ int interval;
+
+ interval = dbus_timeout_get_interval (tcb->timeout);
+
+ interval_seconds = interval / 1000;
+ interval_milliseconds = interval - interval_seconds * 1000;
+
+ 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 = expiration_tv_sec - tv_sec;
+ msec = (expiration_tv_usec - tv_usec) / 1000;
+
+#if 0
+ printf ("Interval is %ld seconds %ld msecs\n",
+ interval_seconds,
+ interval_milliseconds);
+ printf ("Now is %lu seconds %lu usecs\n",
+ tv_sec, tv_usec);
+ printf ("Exp is %lu seconds %lu usecs\n",
+ expiration_tv_sec, expiration_tv_usec);
+ printf ("Pre-correction, remaining sec %ld msec %ld\n", sec, msec);
+#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 millseconds.
+ */
+ if (sec < 0 || (sec == 0 && msec < 0))
+ msec = 0;
+ else
+ {
+ if (msec < 0)
+ {
+ msec += 1000;
+ sec -= 1;
+ }
+
+ if (sec > interval_seconds ||
+ (sec == interval_seconds && msec > interval_milliseconds))
+ {
+ /* The system time has been set backwards, reset the timeout */
+ tcb->last_tv_sec = tv_sec;
+ tcb->last_tv_usec = tv_usec;
+
+ msec = MIN (_DBUS_INT_MAX, interval);
+
+ _dbus_verbose ("System clock went backward\n");
+ }
+ else
+ {
+ msec = MIN (_DBUS_INT_MAX, (unsigned int)msec + 1000 * (unsigned int)sec);
+ }
+ }
+
+ *timeout = msec;
+
+#if 0
+ printf ("Timeout expires in %d milliseconds\n", *timeout);
+#endif
+
+ return msec == 0;
+}
+
+/* Returns TRUE if we have any timeouts or 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)
+{
+ dbus_bool_t retval;
+ DBusPollFD *fds;
+ int n_fds;
+ WatchCallback **watches_for_fds;
+ 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;
+ oom_watch_pending = FALSE;
+ orig_depth = loop->depth;
+
+#if 0
+ _dbus_verbose (" iterate %d timeouts %d watches\n",
+ loop->timeout_count, loop->watch_count);
+#endif
+
+ if (loop->callbacks == NULL)
+ {
+ _dbus_loop_quit (loop);
+ goto next_iteration;
+ }
+
+ /* count enabled 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)
+ {
+ WatchCallback *wcb = WATCH_CALLBACK (cb);
+
+ if (!wcb->last_iteration_oom &&
+ dbus_watch_get_enabled (wcb->watch))
+ ++n_fds;
+ }
+
+ link = next;
+ }
+
+ /* fill our array of fds and watches */
+ if (n_fds > 0)
+ {
+ fds = dbus_new0 (DBusPollFD, n_fds);
+ while (fds == NULL)
+ {
+ _dbus_wait_for_memory ();
+ fds = dbus_new0 (DBusPollFD, n_fds);
+ }
+
+ watches_for_fds = dbus_new (WatchCallback*, n_fds);
+ while (watches_for_fds == NULL)
+ {
+ _dbus_wait_for_memory ();
+ watches_for_fds = dbus_new (WatchCallback*, n_fds);
+ }
+
+ i = 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;
+ }
+ else if (dbus_watch_get_enabled (wcb->watch))
+ {
+ watches_for_fds[i] = wcb;
+
+ flags = dbus_watch_get_flags (wcb->watch);
+
+ fds[i].fd = dbus_watch_get_fd (wcb->watch);
+ if (flags & DBUS_WATCH_READABLE)
+ fds[i].events |= _DBUS_POLLIN;
+ if (flags & DBUS_WATCH_WRITABLE)
+ fds[i].events |= _DBUS_POLLOUT;
+
+ ++i;
+ }
+ }
+
+ link = next;
+ }
+
+ _dbus_assert (i == n_fds);
+ }
+
+ timeout = -1;
+ if (loop->timeout_count > 0)
+ {
+ unsigned long tv_sec;
+ unsigned long tv_usec;
+
+ retval = TRUE;
+
+ _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);
+
+ _dbus_assert (timeout >= 0);
+
+ if (timeout == 0)
+ break; /* it's not going to get shorter... */
+ }
+
+ link = next;
+ }
+ }
+
+ if (!block)
+ {
+ timeout = 0;
+#if 0
+ printf ("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 ());
+
+ 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 0
+ printf (" invoking timeout\n");
+#endif
+
+ (* tcb->function) (tcb->timeout,
+ cb->data);
+ }
+ }
+
+ 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;
+
+ retval = TRUE;
+ }
+ }
+
+ ++i;
+ }
+ }
+
+ next_iteration:
+ dbus_free (fds);
+ dbus_free (watches_for_fds);
+
+ return retval;
+}
+
+void
+_dbus_loop_run (DBusLoop *loop)
+{
+ int our_exit_depth;
+
+ _dbus_loop_ref (loop);
+
+ our_exit_depth = loop->depth;
+ loop->depth += 1;
+
+ 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;
+}
+
+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_sleep_milliseconds (_dbus_get_oom_wait ());
+}
projects / thirdparty / dbus.git / commitdiff
