qmp hmp: Factor out common "using spice" test

Into qemu_using_spice().  For want of a better place, put it next the
existing monitor command handler dummies in qemu-spice.h.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>

include/ui/qemu-spice.h

@@ -88,4 +88,14 @@ static inline int qemu_spice_display_add_client(int csock, int skipauth,
 
 #endif /* CONFIG_SPICE */
 
+static inline bool qemu_using_spice(Error **errp)
+{
+    if (!using_spice) {
+        /* correct one? spice isn't a device ,,, */
+        error_set(errp, QERR_DEVICE_NOT_ACTIVE, "spice");
+        return false;
+    }
+    return true;
+}
+
 #endif /* QEMU_SPICE_H */

monitor.c

@@ -1095,11 +1095,12 @@ static int client_migrate_info(Monitor *mon, const QDict *qdict,
     const char *subject  = qdict_get_try_str(qdict, "cert-subject");
     int port             = qdict_get_try_int(qdict, "port", -1);
     int tls_port         = qdict_get_try_int(qdict, "tls-port", -1);
+    Error *err;
     int ret;
 
     if (strcmp(protocol, "spice") == 0) {
-        if (!using_spice) {
-            qerror_report(QERR_DEVICE_NOT_ACTIVE, "spice");
+        if (!qemu_using_spice(&err)) {
+            qerror_report_err(err);
             return -1;
         }
 

qmp.c

@@ -287,9 +287,7 @@ void qmp_set_password(const char *protocol, const char *password,
     }
 
     if (strcmp(protocol, "spice") == 0) {
-        if (!using_spice) {
-            /* correct one? spice isn't a device ,,, */
-            error_set(errp, QERR_DEVICE_NOT_ACTIVE, "spice");
+        if (!qemu_using_spice(errp)) {
             return;
         }
         rc = qemu_spice_set_passwd(password, fail_if_connected,
@@ -335,9 +333,7 @@ void qmp_expire_password(const char *protocol, const char *whenstr,
     }
 
     if (strcmp(protocol, "spice") == 0) {
-        if (!using_spice) {
-            /* correct one? spice isn't a device ,,, */
-            error_set(errp, QERR_DEVICE_NOT_ACTIVE, "spice");
+        if (!qemu_using_spice(errp)) {
             return;
         }
         rc = qemu_spice_set_pw_expire(when);
@@ -575,8 +571,7 @@ void qmp_add_client(const char *protocol, const char *fdname,
     }
 
     if (strcmp(protocol, "spice") == 0) {
-        if (!using_spice) {
-            error_set(errp, QERR_DEVICE_NOT_ACTIVE, "spice");
+        if (!qemu_using_spice(errp)) {
             close(fd);
             return;
         }