mutter/cogl/cogl-glib-source.c
Robert Bragg ea3d8eca91 Don't take internal references on the context
We want applications to fully control the lifetime of a CoglContext
without having to worry that internal resources (such as the default
2d,3d and rectangle textures, or any caches we maintain) could result in
circular references that keep the context alive. We also want to avoid
making CoglContext into a special kind of object that isn't ref-counted
or that can't be used with object apis such as
cogl_object_set_user_data. Being able to reliably destroy the context is
important on platforms such as Android where you may be required
bring-up and tear-down a CoglContext numerous times throughout the
applications lifetime. A dissadvantage of this policy is that it is now
possible to leave other object such as framebuffers in an inconsistent
state if the context is unreferenced and destroyed. The documentation
states that all objects that directly or indirectly depend on a context
that has been destroyed will be left in an inconsistent state and must
not be accessed thereafter. Applications (such as Android applications)
that need to cleanly destroy and re-create Cogl resources should make
sure to manually unref these dependant objects before destroying the
context.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 23ce51beba1bb739a224e47614a59327dfbb65af)
2012-09-17 23:06:20 +01:00

193 lines
5.0 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2011 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl-glib-source.h"
#include "cogl-poll.h"
typedef struct _CoglGLibSource
{
GSource source;
CoglContext *context;
GArray *poll_fds;
int64_t expiration_time;
} CoglGLibSource;
static CoglBool
cogl_glib_source_poll_fds_changed (CoglGLibSource *cogl_source,
const CoglPollFD *poll_fds,
int n_poll_fds)
{
int i;
if (cogl_source->poll_fds->len != n_poll_fds)
return TRUE;
for (i = 0; i < n_poll_fds; i++)
if (g_array_index (cogl_source->poll_fds, CoglPollFD, i).fd !=
poll_fds[i].fd)
return TRUE;
return FALSE;
}
static CoglBool
cogl_glib_source_prepare (GSource *source, int *timeout)
{
CoglGLibSource *cogl_source = (CoglGLibSource *) source;
CoglPollFD *poll_fds;
int n_poll_fds;
int64_t cogl_timeout;
int i;
cogl_poll_get_info (cogl_source->context,
&poll_fds,
&n_poll_fds,
&cogl_timeout);
/* We have to be careful not to call g_source_add/remove_poll unless
the FDs have changed because it will cause the main loop to
immediately wake up. If we call it every time the source is
prepared it will effectively never go idle. */
if (cogl_glib_source_poll_fds_changed (cogl_source, poll_fds, n_poll_fds))
{
/* Remove any existing polls before adding the new ones */
for (i = 0; i < cogl_source->poll_fds->len; i++)
{
GPollFD *poll_fd = &g_array_index (cogl_source->poll_fds, GPollFD, i);
g_source_remove_poll (source, poll_fd);
}
g_array_set_size (cogl_source->poll_fds, n_poll_fds);
for (i = 0; i < n_poll_fds; i++)
{
GPollFD *poll_fd = &g_array_index (cogl_source->poll_fds, GPollFD, i);
poll_fd->fd = poll_fds[i].fd;
g_source_add_poll (source, poll_fd);
}
}
/* Update the events */
for (i = 0; i < n_poll_fds; i++)
{
GPollFD *poll_fd = &g_array_index (cogl_source->poll_fds, GPollFD, i);
poll_fd->events = poll_fds[i].events;
poll_fd->revents = 0;
}
if (cogl_timeout == -1)
{
*timeout = -1;
cogl_source->expiration_time = -1;
}
else
{
/* Round up to ensure that we don't try again too early */
*timeout = (cogl_timeout + 999) / 1000;
cogl_source->expiration_time = (g_source_get_time (source) +
cogl_timeout);
}
return *timeout == 0;
}
static CoglBool
cogl_glib_source_check (GSource *source)
{
CoglGLibSource *cogl_source = (CoglGLibSource *) source;
int i;
if (cogl_source->expiration_time >= 0 &&
g_source_get_time (source) >= cogl_source->expiration_time)
return TRUE;
for (i = 0; i < cogl_source->poll_fds->len; i++)
{
GPollFD *poll_fd = &g_array_index (cogl_source->poll_fds, GPollFD, i);
if (poll_fd->revents != 0)
return TRUE;
}
return FALSE;
}
static CoglBool
cogl_glib_source_dispatch (GSource *source,
GSourceFunc callback,
void *user_data)
{
CoglGLibSource *cogl_source = (CoglGLibSource *) source;
CoglPollFD *poll_fds =
(CoglPollFD *) &g_array_index (cogl_source->poll_fds, GPollFD, 0);
cogl_poll_dispatch (cogl_source->context,
poll_fds,
cogl_source->poll_fds->len);
return TRUE;
}
static void
cogl_glib_source_finalize (GSource *source)
{
CoglGLibSource *cogl_source = (CoglGLibSource *) source;
g_array_free (cogl_source->poll_fds, TRUE);
}
static GSourceFuncs
cogl_glib_source_funcs =
{
cogl_glib_source_prepare,
cogl_glib_source_check,
cogl_glib_source_dispatch,
cogl_glib_source_finalize
};
GSource *
cogl_glib_source_new (CoglContext *context,
int priority)
{
GSource *source;
CoglGLibSource *cogl_source;
source = g_source_new (&cogl_glib_source_funcs,
sizeof (CoglGLibSource));
cogl_source = (CoglGLibSource *) source;
cogl_source->context = context;
cogl_source->poll_fds = g_array_new (FALSE, FALSE, sizeof (GPollFD));
if (priority != G_PRIORITY_DEFAULT)
g_source_set_priority (source, priority);
return source;
}