vsh: Prune string list returned by completer

Instead of having completers prune returned string list based on
user's input we can do that right after the callback is called.
Only strings matching the prefix will be presented to the user
then.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

tools/vsh.c

@@ -2738,6 +2738,40 @@ vshReadlineCommandFindOpt(const vshCmd *partial,
 }
 
 
+static int
+vshCompleterFilter(char ***list,
+                   const char *text)
+{
+    char **newList = NULL;
+    size_t newList_len = 0;
+    size_t list_len;
+    size_t i;
+
+    if (!list || !*list)
+        return -1;
+
+    list_len = virStringListLength((const char **) *list);
+
+    if (VIR_ALLOC_N(newList, list_len + 1) < 0)
+        return -1;
+
+    for (i = 0; i < list_len; i++) {
+        if (!STRPREFIX((*list)[i], text)) {
+            VIR_FREE((*list)[i]);
+            continue;
+        }
+
+        VIR_STEAL_PTR(newList[newList_len], (*list)[i]);
+        newList_len++;
+    }
+
+    ignore_value(VIR_REALLOC_N_QUIET(newList, newList_len + 1));
+    VIR_FREE(*list);
+    *list = newList;
+    return 0;
+}
+
+
 static char *
 vshReadlineParse(const char *text, int state)
 {
@@ -2793,7 +2827,14 @@ vshReadlineParse(const char *text, int state)
                 char **completer_list = opt->completer(autoCompleteOpaque,
                                                        partial,
                                                        opt->completer_flags);
-                if (virStringListMerge(&list, &completer_list) < 0) {
+
+                /* For string list returned by completer we have to do
+                 * filtering based on @text because completer returns all
+                 * possible strings. */
+
+                if (completer_list &&
+                    (vshCompleterFilter(&completer_list, text) < 0 ||
+                     virStringListMerge(&list, &completer_list) < 0)) {
                     virStringListFree(completer_list);
                     goto cleanup;
                 }