ui/spice-app: don't use qemu_chr_open_spice_port directly

Save the parent object's open function pointer in the (new)
VCChardevClass struct instead before overwriting it, so we
can look it up when needed.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20201014121120.13482-3-kraxel@redhat.com

ui/spice-app.c

@@ -44,11 +44,15 @@ static char *sock_path;
 struct VCChardev {
     SpiceChardev parent;
 };
-typedef struct VCChardev VCChardev;
+
+struct VCChardevClass {
+    ChardevClass parent;
+    void (*parent_open)(Chardev *chr, ChardevBackend *backend,
+                        bool *be_opened, Error **errp);
+};
 
 #define TYPE_CHARDEV_VC "chardev-vc"
-DECLARE_INSTANCE_CHECKER(VCChardev, VC_CHARDEV,
-                         TYPE_CHARDEV_VC)
+OBJECT_DECLARE_TYPE(VCChardev, VCChardevClass, CHARDEV_VC)
 
 static ChardevBackend *
 chr_spice_backend_new(void)
@@ -66,6 +70,7 @@ static void vc_chr_open(Chardev *chr,
                         bool *be_opened,
                         Error **errp)
 {
+    VCChardevClass *vc = CHARDEV_VC_GET_CLASS(chr);
     ChardevBackend *be;
     const char *fqdn = NULL;
 
@@ -80,7 +85,7 @@ static void vc_chr_open(Chardev *chr,
     be = chr_spice_backend_new();
     be->u.spiceport.data->fqdn = fqdn ?
         g_strdup(fqdn) : g_strdup_printf("org.qemu.console.%s", chr->label);
-    qemu_chr_open_spice_port(chr, be, be_opened, errp);
+    vc->parent_open(chr, be, be_opened, errp);
     qapi_free_ChardevBackend(be);
 }
 
@@ -91,8 +96,11 @@ static void vc_chr_set_echo(Chardev *chr, bool echo)
 
 static void char_vc_class_init(ObjectClass *oc, void *data)
 {
+    VCChardevClass *vc = CHARDEV_VC_CLASS(oc);
     ChardevClass *cc = CHARDEV_CLASS(oc);
 
+    vc->parent_open = cc->open;
+
     cc->parse = qemu_chr_parse_vc;
     cc->open = vc_chr_open;
     cc->chr_set_echo = vc_chr_set_echo;
@@ -103,6 +111,7 @@ static const TypeInfo char_vc_type_info = {
     .parent = TYPE_CHARDEV_SPICEPORT,
     .instance_size = sizeof(VCChardev),
     .class_init = char_vc_class_init,
+    .class_size = sizeof(VCChardevClass),
 };
 
 static void spice_app_atexit(void)