[virt-tools-list] [PATCH virt-viewer 4/4] Fullscreen auto-conf: wait for server to be configured

[Jonathon Jongsma]

When doing fullscreen auto-conf, we send down a new configuration to the
server before the display chanels are connected. Due to race conditions
in the server, we sometimes get an initial monitors-config message with
the guest's old display state. If the guest happened to have more
displays enabled than we need for auto-conf, those extra displays
windows will remain open, and the auto-conf will not succeed.  To avoid
this, we delay creating any windows and displays until the guest
responds with a monitor config equal to the one we sent down for
auto-conf. This allows the server some time to "settle", and prevents us
from opening more windows on the client than we want. If for some reason
the guest cannot be configured properly within a certain time frame, the
client will go ahead and open displays to match the current state of the
server.

Resolves: rhbz#1200750
---
 src/virt-viewer-session-spice.c | 121 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 118 insertions(+), 3 deletions(-)

diff --git a/src/virt-viewer-session-spice.c b/src/virt-viewer-session-spice.c
index 4620bba..054448d 100644
--- a/src/virt-viewer-session-spice.c
+++ b/src/virt-viewer-session-spice.c
@@ -66,6 +66,7 @@ struct _VirtViewerSessionSpicePrivate {
     AutoConfState auto_conf_state;
     GList *display_channels;
     GArray *fullscreen_config;
+    guint auto_conf_timer;
 };
 
 #define VIRT_VIEWER_SESSION_SPICE_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE((o), VIRT_VIEWER_TYPE_SESSION_SPICE, VirtViewerSessionSpicePrivate))
@@ -704,9 +705,8 @@ destroy_display(gpointer data)
 }
 
 static void
-virt_viewer_session_spice_display_monitors(SpiceChannel *channel,
-                                           GParamSpec *pspec G_GNUC_UNUSED,
-                                           VirtViewerSessionSpice *self)
+virt_viewer_session_spice_process_monitors_for_display_channel(VirtViewerSessionSpice *self,
+                                                               SpiceChannel *channel)
 {
     GArray *monitors = NULL;
     GPtrArray *displays = NULL;
@@ -759,6 +759,105 @@ virt_viewer_session_spice_display_monitors(SpiceChannel *channel,
 
 }
 
+static gboolean
+virt_viewer_session_spice_displays_match_initial_config(VirtViewerSessionSpice *self)
+{
+    cairo_region_t *region1, *region2;
+    GList *l;
+    int i;
+    GArray *rects = g_array_new(FALSE, TRUE, sizeof(GdkRectangle));
+    VirtViewerApp *app = virt_viewer_session_get_app(VIRT_VIEWER_SESSION(self));
+    GList *initial_displays = virt_viewer_app_get_initial_displays(app);
+    gboolean match = FALSE;
+
+    if (!virt_viewer_app_get_fullscreen(app))
+        goto cleanup;
+
+    for (l = self->priv->display_channels; l != NULL; l = l->next) {
+        GArray *monitors = NULL;
+        g_object_get(l->data,
+                     "monitors", &monitors,
+                     NULL);
+
+        if (!monitors)
+            continue;
+
+        for (i = 0; i < monitors->len; i++) {
+            SpiceDisplayMonitorConfig *monitor = &g_array_index(monitors, SpiceDisplayMonitorConfig, i);
+
+            if (monitor->width == 0 || monitor->height == 0)
+                continue;
+
+            GdkRectangle rect = {
+                .x = monitor->x,
+                .y = monitor->y,
+                .width = monitor->width,
+                .height = monitor->height
+            };
+            g_array_append_val(rects, rect);
+        }
+    }
+
+    if (rects->len != g_list_length(initial_displays))
+        goto cleanup;
+
+    region1 = cairo_region_create_rectangles((cairo_rectangle_int_t*)rects->data,
+                                             rects->len);
+    region2 = cairo_region_create_rectangles((cairo_rectangle_int_t*)self->priv->fullscreen_config->data,
+                                             self->priv->fullscreen_config->len);
+
+    match = cairo_region_equal(region1, region2);
+
+    cairo_region_destroy(region1);
+    cairo_region_destroy(region2);
+
+cleanup:
+    g_list_free(initial_displays);
+    g_array_unref(rects);
+
+    return match;
+}
+
+static void
+virt_viewer_session_spice_auto_conf_complete(VirtViewerSessionSpice *self)
+{
+        GList *l;
+
+        if (self->priv->auto_conf_timer) {
+            g_source_remove(self->priv->auto_conf_timer);
+            self->priv->auto_conf_timer = 0;
+        }
+
+        self->priv->auto_conf_state = AUTO_CONF_STATE_COMPLETE;
+
+        /* now process all pending display channels, creating displays, etc */
+        for (l = self->priv->display_channels; l != NULL; l = l->next)
+            virt_viewer_session_spice_process_monitors_for_display_channel(self, l->data);
+}
+
+static void
+virt_viewer_session_spice_display_monitors(SpiceChannel *channel,
+                                           GParamSpec *pspec G_GNUC_UNUSED,
+                                           VirtViewerSessionSpice *self)
+{
+    if (self->priv->auto_conf_state == AUTO_CONF_STATE_SENT) {
+
+        /* At startup, the server can sometimes send up old monitor
+         * configurations even if we've sent the initial auto conf. This will
+         * generally be followed by another monitor update with the correct
+         * configuration. So if we've sent our auto-conf configuration, check
+         * whether this is the correct config and process all pending updates.
+         * If not, wait for the next update. */
+        if (virt_viewer_session_spice_displays_match_initial_config(self))
+            virt_viewer_session_spice_auto_conf_complete(self);
+
+        g_debug("Displays don't match initial config. Waiting for next monitor config update");
+        return;
+    }
+
+    virt_viewer_session_spice_process_monitors_for_display_channel(self, channel);
+}
+
 static void
 virt_viewer_session_spice_channel_new(SpiceSession *s,
                                       SpiceChannel *channel,
@@ -832,6 +931,16 @@ property_notify_do_auto_conf(GObject *gobject G_GNUC_UNUSED,
 }
 
 static gboolean
+timeout_complete_auto_conf(gpointer data)
+{
+    VirtViewerSessionSpice *self = VIRT_VIEWER_SESSION_SPICE(data);
+    g_debug("Guest wasn't configured in time, completing auto-conf");
+    virt_viewer_session_spice_auto_conf_complete(self);
+
+    return FALSE;
+}
+
+static gboolean
 virt_viewer_session_spice_fullscreen_auto_conf(VirtViewerSessionSpice *self)
 {
     GdkScreen *screen = gdk_screen_get_default();
@@ -901,6 +1010,12 @@ virt_viewer_session_spice_fullscreen_auto_conf(VirtViewerSessionSpice *self)
     spice_main_send_monitor_config(cmain);
     self->priv->auto_conf_state = AUTO_CONF_STATE_SENT;
 
+    /* Wait for the guest to respond with the exact configuration we just sent
+     * down. If the configuration doesn't happen before the timeout, just show
+     * the current displays */
+    self->priv->auto_conf_timer =
+        g_timeout_add_seconds(2, timeout_complete_auto_conf, self);
+
     self->priv->fullscreen_config = config;
     return TRUE;
 }
-- 
2.1.0