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[x11-texture-pixmap] Fixes a reported lockup due to an undesireable X server grab

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A lockup was reported by fargoilas on #clutter and removing the server grab in
clutter_x11_texture_pixmap_sync_window fixed the problem.

We were doing an x server grab to guarantee that if the XGetWindowAttributes
request reported that our redirected window was viewable then we would also
be able to get a valid pixmap name.  (the composite protocol says it's an
error to request a name for a window if it's not viewable) Without the grab
there would be a race condition.

Instead we now handle error conditions gracefully.
This commit is contained in:
Robert Bragg 2009-04-17 19:05:21 +01:00
parent ffefbe4661
commit 1d2ac51ea3
1 changed files with 28 additions and 20 deletions
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48
clutter/x11/clutter-x11-texture-pixmap.c
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@ -1196,32 +1196,40 @@ clutter_x11_texture_pixmap_sync_window (ClutterX11TexturePixmap *texture)
{
XWindowAttributes attr;
Display *dpy = clutter_x11_get_default_display ();
gboolean mapped, notify_x, notify_y, notify_override_redirect;
gboolean mapped = FALSE;
gboolean notify_x = FALSE;
gboolean notify_y = FALSE;
gboolean notify_override_redirect = FALSE;
Status status;
/*
* Make sure the window is mapped when getting the pixmap -- it's what
* compiz does.
/* NB: It's only valid to name a pixmap if the window is viewable.
*
* We don't explicitly check this though since there would be a race
* between checking and naming unless we use a server grab which is
* undesireable.
*
* Instead we gracefully handle any error with naming the pixmap.
*/
clutter_x11_trap_x_errors ();
XGrabServer (dpy);
XGetWindowAttributes (dpy, priv->window, &attr);
mapped = attr.map_state == IsViewable;
if (mapped)
pixmap = XCompositeNameWindowPixmap (dpy, priv->window);
else
pixmap = None;
pixmap = XCompositeNameWindowPixmap (dpy, priv->window);
XUngrabServer (dpy);
clutter_x11_untrap_x_errors ();
status = XGetWindowAttributes (dpy, priv->window, &attr);
if (status != 0)
{
notify_x = attr.x != priv->window_x;
notify_y = attr.y != priv->window_y;
notify_override_redirect = attr.override_redirect != priv->override_redirect;
priv->window_x = attr.x;
priv->window_y = attr.y;
priv->override_redirect = attr.override_redirect;
}
notify_x = attr.x != priv->window_x;
notify_y = attr.y != priv->window_y;
notify_override_redirect = attr.override_redirect != priv->override_redirect;
priv->window_x = attr.x;
priv->window_y = attr.y;
priv->override_redirect = attr.override_redirect;
/* We rely on XGetWindowAttributes() implicitly syncing with the server
* so if there was an error naming the pixmap that will have been
* caught by now. */
if (clutter_x11_untrap_x_errors ())
pixmap = None;
g_object_ref (texture); /* guard against unparent */
if (pixmap)