virsh: Add event name completion to 'secret-event' command

The patch code originally authored by Michal Privoznik, Please refer to
https://www.redhat.com/archives/libvir-list/2018-May/msg01022.html

Signed-off-by: Lin Ma <lma@suse.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

tools/virsh-completer.c

@@ -26,6 +26,7 @@
 #include "virsh.h"
 #include "virsh-pool.h"
 #include "virsh-util.h"
+#include "virsh-secret.h"
 #include "internal.h"
 #include "virutil.h"
 #include "viralloc.h"
@@ -649,3 +650,29 @@ virshAllocpagesPagesizeCompleter(vshControl *ctl,
     VIR_FREE(ret);
     goto cleanup;
 }
+
+
+char **
+virshSecretEventNameCompleter(vshControl *ctl ATTRIBUTE_UNUSED,
+                              const vshCmd *cmd ATTRIBUTE_UNUSED,
+                              unsigned int flags)
+{
+    size_t i;
+    char **ret = NULL;
+
+    virCheckFlags(0, NULL);
+
+    if (VIR_ALLOC_N(ret, VIR_SECRET_EVENT_ID_LAST) < 0)
+        goto error;
+
+    for (i = 0; i < VIR_SECRET_EVENT_ID_LAST; i++) {
+        if (VIR_STRDUP(ret[i], virshSecretEventCallbacks[i].name) < 0)
+            goto error;
+    }
+
+    return ret;
+
+ error:
+    virStringListFree(ret);
+    return NULL;
+}

tools/virsh-completer.h

@@ -78,4 +78,8 @@ char ** virshAllocpagesPagesizeCompleter(vshControl *ctl,
                                     const vshCmd *cmd,
                                     unsigned int flags);
 
+char ** virshSecretEventNameCompleter(vshControl *ctl,
+                                      const vshCmd *cmd,
+                                      unsigned int flags);
+
 #endif

tools/virsh-secret.c

@@ -671,6 +671,7 @@ static const vshCmdOptDef opts_secret_event[] = {
     },
     {.name = "event",
      .type = VSH_OT_STRING,
+     .completer = virshSecretEventNameCompleter,
      .help = N_("which event type to wait for")
     },
     {.name = "loop",