fix(shell): coverity scan problem fixed

src/kit/shell/src/tire.c

@@ -325,30 +325,26 @@ void matchPrefixFromTree(STire* tire, char* prefix, SMatch* match) {
 }
 
 SMatch* matchPrefix(STire* tire, char* prefix, SMatch* match) {
-    if(match == NULL) {
-        match = (SMatch* )tmalloc(sizeof(SMatch));
-        memset(match, 0, sizeof(SMatch));
+  SMatch* rMatch = match; // define return match
+  if (rMatch == NULL) {
+    rMatch = (SMatch*)taosMemoryMalloc(sizeof(SMatch));
+    memset(rMatch, 0, sizeof(SMatch));
   }
 
   switch (tire->type) {
     case TIRE_TREE:
-        matchPrefixFromTree(tire, prefix, match);
+      matchPrefixFromTree(tire, prefix, rMatch);
+      break;
     case TIRE_LIST:
-        matchPrefixFromList(tire, prefix, match);
+      matchPrefixFromList(tire, prefix, rMatch);
+      break;
     default:
       break;
   }
 
-    // return if need
-    if (match->count == 0) {
-        freeMatch(match);
-        match = NULL;
-    }    
-
-    return match;  
+  return rMatch;
 }
 
-
 // get all items from tires tree
 void enumFromList(STire* tire, SMatch* match) {
     StrName * item = tire->head;
@@ -395,8 +391,10 @@ SMatch* enumAll(STire* tire) {
     switch (tire->type) {
       case TIRE_TREE: 
         enumFromTree(tire, match);
+        break;
       case TIRE_LIST:
         enumFromList(tire, match);
+        break;
       default:
         break;
     }