[gnome-screensaver/gnome-2-28] Work around x errors by asking dialog to die on cancel

[William Jon McCann <mccann src gnome org>]

commit 98f8a22412cf388217fd5b88915eadd274d68520
Author: Chris Coulson <chriscoulson googlemail com>
Date:   Thu Jan 28 21:29:17 2010 -0500

    Work around x errors by asking dialog to die on cancel
    
    Basically, what is happening is that gnome-screensaver-dialog exits after the
    5th failed attempt at unlocking the screen, but before the shake animation
    finishes. If the timing is slightly unlucky, this results in gnome-screensaver
    accessing X resources that have already been destroyed (I ran it through
    xtrace, and that showed this happening)
    
    My patch fixes this by making gnome-screensaver-dialog request to
    gnome-screensaver that it be terminated after the 5th failed attempt (rather
    than exitting straight away, although there is a fallback timeout too).
    gnome-screensaver then terminates the dialog after it is finished with the
    shake animation, to avoid the race condition that is currently making it crash.

 src/gnome-screensaver-dialog.c |   22 +++++++++++++++++++++-
 src/gs-window-x11.c            |   24 ++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 1 deletions(-)
---
diff --git a/src/gnome-screensaver-dialog.c b/src/gnome-screensaver-dialog.c
index 88d14a0..9d72fcb 100644
--- a/src/gnome-screensaver-dialog.c
+++ b/src/gnome-screensaver-dialog.c
@@ -29,6 +29,7 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
+#include <signal.h>
 
 #include <glib/gi18n.h>
 #include <gdk/gdkx.h>
@@ -326,6 +327,21 @@ response_cb (GSLockPlug *plug,
 }
 
 static gboolean
+response_request_quit (void)
+{
+        printf ("REQUEST QUIT\n");
+        fflush (stdout);
+        return FALSE;
+}
+
+static gboolean
+quit_timeout_cb (gpointer data)
+{
+        gtk_main_quit ();
+        return FALSE;
+}
+
+static gboolean
 auth_check_idle (GSLockPlug *plug)
 {
         gboolean     res;
@@ -347,7 +363,11 @@ auth_check_idle (GSLockPlug *plug)
                 } else {
                         gs_debug ("Authentication failed, quitting (max failures)");
                         again = FALSE;
-                        gtk_main_quit ();
+                        /* Don't quit immediately, but rather request that gnome-screensaver
+                         * terminates us after it has finished the dialog shake. Time out
+                         * after 5 seconds and quit anyway if this doesn't happen though */
+                        g_idle_add ((GSourceFunc)response_request_quit, NULL);
+                        g_timeout_add (5000, (GSourceFunc)quit_timeout_cb, NULL);
                 }
         }
 
diff --git a/src/gs-window-x11.c b/src/gs-window-x11.c
index 2a74e10..ea6c1cd 100644
--- a/src/gs-window-x11.c
+++ b/src/gs-window-x11.c
@@ -91,6 +91,8 @@ struct GSWindowPrivate
         gint       lock_pid;
         gint       lock_watch_id;
         gint       dialog_response;
+        gboolean   dialog_quit_requested;
+        gboolean   dialog_shake_in_progress;
 
         gint       keyboard_pid;
         gint       keyboard_watch_id;
@@ -1383,6 +1385,16 @@ gs_window_dialog_finish (GSWindow *window)
         remove_key_events (window);
 }
 
+static void
+maybe_kill_dialog (GSWindow *window)
+{
+        if (!window->priv->dialog_shake_in_progress
+            && window->priv->dialog_quit_requested
+            && window->priv->lock_pid > 0) {
+                kill (window->priv->lock_pid, SIGTERM);
+        }
+}
+
 /* very rudimentary animation for indicating an auth failure */
 static void
 shake_dialog (GSWindow *window)
@@ -1391,6 +1403,8 @@ shake_dialog (GSWindow *window)
         guint left;
         guint right;
 
+        window->priv->dialog_shake_in_progress = TRUE;
+
         for (i = 0; i < 9; i++) {
                 if (i % 2 == 0) {
                         left = 30;
@@ -1415,6 +1429,9 @@ shake_dialog (GSWindow *window)
 
                 g_usleep (10000);
         }
+
+        window->priv->dialog_shake_in_progress = FALSE;
+        maybe_kill_dialog (window);
 }
 
 static gboolean
@@ -1457,6 +1474,10 @@ lock_command_watch (GIOChannel   *source,
                                         window->priv->dialog_response = DIALOG_RESPONSE_CANCEL;
                                 }
                                 finished = TRUE;
+                        } else if (strstr (line, "REQUEST QUIT") != NULL) {
+                                gs_debug ("Got request for quit");
+                                window->priv->dialog_quit_requested = TRUE;
+                                maybe_kill_dialog (window);
                         }
                         break;
                 case G_IO_STATUS_EOF:
@@ -1570,6 +1591,9 @@ popup_dialog_idle (GSWindow *window)
 
         set_invisible_cursor (GTK_WIDGET (window)->window, FALSE);
 
+        window->priv->dialog_quit_requested = FALSE;
+        window->priv->dialog_shake_in_progress = FALSE;
+
         result = spawn_on_window (window,
                                   command->str,
                                   &window->priv->lock_pid,