Use the display ID to configure fullscreen monitors

When starting virt-viewer in fullscreen mode, we generally try to
arrange guest displays exactly the same as client monitors. So if a
client machine has two monitors, we'll try to enable display 0 and 1 on
the guest (in that order). However, when using the configuration file to
map fullscreen displays to different monitors, the guest displays may
not be sequential, or there may be displays missing. For example,
consider the following configuration:

monitor-mapping=1:2;2:1

In virt_viewer_session_spice_fullscreen_auto_conf(), we were building an
array of GdkRectangles for the initial monitors that we want to enable
on the guest. We then configured the guest displays using the index of
the array for the as the id of the guest display. But when displays
are sparse or are out-of-sequence, the array index will not match the
>ntended display ID. This created problems where displays were arranged
incorrectly. By changing the simple array into a GHashTable, we can keep
the display ID together with the GdkRectangle until we need to use it,
and things will be configured correctly.

This regression was introduced by c586dc8c.

Fixes: rhbz#1267184

src/virt-viewer-session-spice.c

@@ -85,7 +85,7 @@ static void virt_viewer_session_spice_channel_destroy(SpiceSession *s,
 static void virt_viewer_session_spice_smartcard_insert(VirtViewerSession *session);
 static void virt_viewer_session_spice_smartcard_remove(VirtViewerSession *session);
 static gboolean virt_viewer_session_spice_fullscreen_auto_conf(VirtViewerSessionSpice *self);
-static void virt_viewer_session_spice_apply_monitor_geometry(VirtViewerSession *self, GdkRectangle *monitors, guint nmonitors);
+static void virt_viewer_session_spice_apply_monitor_geometry(VirtViewerSession *self, GHashTable *monitors);
 
 static void virt_viewer_session_spice_clear_displays(VirtViewerSessionSpice *self)
 {
@@ -966,9 +966,10 @@ virt_viewer_session_spice_fullscreen_auto_conf(VirtViewerSessionSpice *self)
     GdkScreen *screen = gdk_screen_get_default();
     SpiceMainChannel* cmain = virt_viewer_session_spice_get_main_channel(self);
     VirtViewerApp *app = NULL;
-    GdkRectangle *displays;
+    GHashTable *displays;
+    GHashTableIter iter;
+    gpointer key, value;
     gboolean agent_connected;
-    gint i;
     GList *initial_displays, *l;
     guint ndisplays;
 
@@ -1003,29 +1004,32 @@ virt_viewer_session_spice_fullscreen_auto_conf(VirtViewerSessionSpice *self)
     initial_displays = virt_viewer_app_get_initial_displays(app);
     ndisplays = g_list_length(initial_displays);
     g_debug("Performing full screen auto-conf, %u host monitors", ndisplays);
-    displays = g_new0(GdkRectangle, ndisplays);
+    displays = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, g_free);
 
-    for (i = 0, l = initial_displays; l != NULL; l = l->next, i++) {
-        GdkRectangle* rect = &displays[i];
+    for (l = initial_displays; l != NULL; l = l->next) {
+        GdkRectangle* rect = g_new0(GdkRectangle, 1);;
         gint j = virt_viewer_app_get_initial_monitor_for_display(app, GPOINTER_TO_INT(l->data));
         if (j == -1)
             continue;
 
         gdk_screen_get_monitor_geometry(screen, j, rect);
+        g_hash_table_insert(displays, l->data, rect);
+    }
+
+    virt_viewer_shift_monitors_to_origin(displays);
+
+    g_hash_table_iter_init(&iter, displays);
+    while (g_hash_table_iter_next(&iter, &key, &value)) {
+        GdkRectangle *rect = value;
+        gint j = GPOINTER_TO_INT(key);
+
+        spice_main_set_display(cmain, j, rect->x, rect->y, rect->width, rect->height);
+        spice_main_set_display_enabled(cmain, j, TRUE);
+        g_debug("Set SPICE display %d to (%d,%d)-(%dx%d)",
+                  j, rect->x, rect->y, rect->width, rect->height);
     }
     g_list_free(initial_displays);
-
-    virt_viewer_shift_monitors_to_origin(displays, ndisplays);
-
-    for (i = 0; i < ndisplays; i++) {
-        GdkRectangle *rect = &displays[i];
-
-        spice_main_set_display(cmain, i, rect->x, rect->y, rect->width, rect->height);
-        spice_main_set_display_enabled(cmain, i, TRUE);
-        g_debug("Set SPICE display %d to (%d,%d)-(%dx%d)",
-                  i, rect->x, rect->y, rect->width, rect->height);
-    }
-    g_free(displays);
+    g_hash_table_unref(displays);
 
     spice_main_send_monitor_config(cmain);
     self->priv->did_auto_conf = TRUE;
@@ -1109,13 +1113,16 @@ virt_viewer_session_spice_smartcard_remove(VirtViewerSession *session G_GNUC_UNU
 }
 
 static void
-virt_viewer_session_spice_apply_monitor_geometry(VirtViewerSession *session, GdkRectangle *monitors, guint nmonitors)
+virt_viewer_session_spice_apply_monitor_geometry(VirtViewerSession *session, GHashTable *monitors)
 {
-    guint i;
+    GHashTableIter iter;
+    gpointer key = NULL, value = NULL;
     VirtViewerSessionSpice *self = VIRT_VIEWER_SESSION_SPICE(session);
 
-    for (i = 0; i < nmonitors; i++) {
-        GdkRectangle* rect = &monitors[i];
+    g_hash_table_iter_init(&iter, monitors);
+    while (g_hash_table_iter_next(&iter, &key, &value)) {
+        gint i = GPOINTER_TO_INT(key);
+        GdkRectangle* rect = value;
 
         spice_main_set_display(self->priv->main_channel, i, rect->x,
                                rect->y, rect->width, rect->height);

src/virt-viewer-session.c

@@ -404,49 +404,35 @@ virt_viewer_session_on_monitor_geometry_changed(VirtViewerSession* self,
 {
     VirtViewerSessionClass *klass;
     gboolean all_fullscreen = TRUE;
-    guint nmonitors = 0;
-    GdkRectangle *monitors = NULL;
+    /* GHashTable<gint, GdkRectangle*> */
+    GHashTable *monitors = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, g_free);
     GList *l;
 
     klass = VIRT_VIEWER_SESSION_GET_CLASS(self);
     if (!klass->apply_monitor_geometry)
         return;
 
-    /* find highest monitor ID so we can create the sparse array */
     for (l = self->priv->displays; l; l = l->next) {
         VirtViewerDisplay *d = VIRT_VIEWER_DISPLAY(l->data);
         guint nth = 0;
-        g_object_get(d, "nth-display", &nth, NULL);
-
-        nmonitors = MAX(nth + 1, nmonitors);
-    }
-
-    if (nmonitors == 0)
-        return;
-
-    monitors = g_new0(GdkRectangle, nmonitors);
-    for (l = self->priv->displays; l; l = l->next) {
-        VirtViewerDisplay *d = VIRT_VIEWER_DISPLAY(l->data);
-        guint nth = 0;
-        GdkRectangle *rect = NULL;
+        GdkRectangle *rect = g_new0(GdkRectangle, 1);
 
         g_object_get(d, "nth-display", &nth, NULL);
-        g_return_if_fail(nth < nmonitors);
-        rect = &monitors[nth];
         virt_viewer_display_get_preferred_monitor_geometry(d, rect);
 
         if (virt_viewer_display_get_enabled(d) &&
             !virt_viewer_display_get_fullscreen(d))
             all_fullscreen = FALSE;
+        g_hash_table_insert(monitors, GINT_TO_POINTER(nth), rect);
     }
 
     if (!all_fullscreen)
-        virt_viewer_align_monitors_linear(monitors, nmonitors);
+        virt_viewer_align_monitors_linear(monitors);
 
-    virt_viewer_shift_monitors_to_origin(monitors, nmonitors);
+    virt_viewer_shift_monitors_to_origin(monitors);
 
-    klass->apply_monitor_geometry(self, monitors, nmonitors);
-    g_free(monitors);
+    klass->apply_monitor_geometry(self, monitors);
+    g_hash_table_unref(monitors);
 }
 
 void virt_viewer_session_add_display(VirtViewerSession *session,

src/virt-viewer-session.h

@@ -94,7 +94,8 @@ struct _VirtViewerSessionClass {
     void (*session_cut_text)(VirtViewerSession *session, const gchar *str);
     void (*session_bell)(VirtViewerSession *session);
     void (*session_cancelled)(VirtViewerSession *session);
-    void (*apply_monitor_geometry)(VirtViewerSession *session, GdkRectangle* monitors, guint nmonitors);
+    /* monitors = GHashTable<int, GdkRectangle*> */
+    void (*apply_monitor_geometry)(VirtViewerSession *session, GHashTable* monitors);
     gboolean (*can_share_folder)(VirtViewerSession *session);
     gboolean (*can_retry_auth)(VirtViewerSession *session);
 };

src/virt-viewer-util.c

@@ -536,11 +536,11 @@ static int
 displays_cmp(const void *p1, const void *p2, gpointer user_data)
 {
     guint diff;
-    GdkRectangle *displays = user_data;
+    GHashTable *displays = user_data;
     guint i = *(guint*)p1;
     guint j = *(guint*)p2;
-    GdkRectangle *m1 = &displays[i];
-    GdkRectangle *m2 = &displays[j];
+    GdkRectangle *m1 = g_hash_table_lookup(displays, GINT_TO_POINTER(i));
+    GdkRectangle *m2 = g_hash_table_lookup(displays, GINT_TO_POINTER(j));
     diff = m1->x - m2->x;
     if (diff == 0)
         diff = m1->y - m2->y;
@@ -550,28 +550,44 @@ displays_cmp(const void *p1, const void *p2, gpointer user_data)
     return diff;
 }
 
+static void find_max_id(gpointer key,
+                        gpointer value G_GNUC_UNUSED,
+                        gpointer user_data)
+{
+    guint *max_id = user_data;
+    guint id = GPOINTER_TO_INT(key);
+    *max_id = MAX(*max_id, id);
+}
+
 void
-virt_viewer_align_monitors_linear(GdkRectangle *displays, guint ndisplays)
+virt_viewer_align_monitors_linear(GHashTable *displays)
 {
     gint i, x = 0;
     guint *sorted_displays;
+    guint max_id = 0;
+    GHashTableIter iter;
+    gpointer key, value;
 
     g_return_if_fail(displays != NULL);
 
-    if (ndisplays == 0)
+    if (g_hash_table_size(displays) == 0)
         return;
 
-    sorted_displays = g_new0(guint, ndisplays);
-    for (i = 0; i < ndisplays; i++)
-        sorted_displays[i] = i;
-    g_qsort_with_data(sorted_displays, ndisplays, sizeof(guint), displays_cmp, displays);
+    g_hash_table_foreach(displays, find_max_id, &max_id);
+    sorted_displays = g_new0(guint, max_id);
+
+    g_hash_table_iter_init(&iter, displays);
+    while (g_hash_table_iter_next(&iter, &key, &value))
+        sorted_displays[GPOINTER_TO_INT(key)] = GPOINTER_TO_INT(key);
+
+    g_qsort_with_data(sorted_displays, max_id, sizeof(guint), displays_cmp, displays);
 
     /* adjust monitor positions so that there's no gaps or overlap between
      * monitors */
-    for (i = 0; i < ndisplays; i++) {
+    for (i = 0; i < max_id; i++) {
         guint nth = sorted_displays[i];
-        g_assert(nth < ndisplays);
-        GdkRectangle *rect = &displays[nth];
+        g_assert(nth < max_id);
+        GdkRectangle *rect = g_hash_table_lookup(displays, GINT_TO_POINTER(nth));
         rect->x = x;
         rect->y = 0;
         x += rect->width;
@@ -591,16 +607,19 @@ virt_viewer_align_monitors_linear(GdkRectangle *displays, guint ndisplays)
  * screen of that size.
  */
 void
-virt_viewer_shift_monitors_to_origin(GdkRectangle *displays, guint ndisplays)
+virt_viewer_shift_monitors_to_origin(GHashTable *displays)
 {
     gint xmin = G_MAXINT;
     gint ymin = G_MAXINT;
-    gint i;
+    GHashTableIter iter;
+    gpointer key, value;
 
-    g_return_if_fail(ndisplays > 0);
+    if (g_hash_table_size(displays) == 0)
+        return;
 
-    for (i = 0; i < ndisplays; i++) {
-        GdkRectangle *display = &displays[i];
+    g_hash_table_iter_init(&iter, displays);
+    while (g_hash_table_iter_next(&iter, &key, &value)) {
+        GdkRectangle *display = value;
         if (display->width > 0 && display->height > 0) {
             xmin = MIN(xmin, display->x);
             ymin = MIN(ymin, display->y);
@@ -610,8 +629,9 @@ virt_viewer_shift_monitors_to_origin(GdkRectangle *displays, guint ndisplays)
 
     if (xmin > 0 || ymin > 0) {
         g_debug("%s: Shifting all monitors by (%i, %i)", G_STRFUNC, xmin, ymin);
-        for (i = 0; i < ndisplays; i++) {
-            GdkRectangle *display = &displays[i];
+        g_hash_table_iter_init(&iter, displays);
+        while (g_hash_table_iter_next(&iter, &key, &value)) {
+            GdkRectangle *display = value;
             if (display->width > 0 && display->height > 0) {
                 display->x -= xmin;
                 display->y -= ymin;

src/virt-viewer-util.h

@@ -57,8 +57,8 @@ gchar* spice_hotkey_to_gtk_accelerator(const gchar *key);
 gint virt_viewer_compare_buildid(const gchar *s1, const gchar *s2);
 
 /* monitor alignment */
-void virt_viewer_align_monitors_linear(GdkRectangle *displays, guint ndisplays);
-void virt_viewer_shift_monitors_to_origin(GdkRectangle *displays, guint ndisplays);
+void virt_viewer_align_monitors_linear(GHashTable *displays);
+void virt_viewer_shift_monitors_to_origin(GHashTable *displays);
 
 #endif