Issue #3352255: Resolve deprecation of strpos and stripos.

Closes #3352255

src/Plugin/views/query/ViewsJsonQuery.php

@@ -269,7 +269,7 @@ class ViewsJsonQuery extends QueryPluginBase {
           $r = $r[$key];
         }
       }
-      elseif (stripos($path, '=') !== FALSE) {
+      elseif (stripos((!empty($path) ? $path : ''), '=') !== FALSE) {
         $search_data = explode('=', $path);
         $array_key = $search_data[0];
         $array_value = $search_data[1];
@@ -306,13 +306,13 @@ class ViewsJsonQuery extends QueryPluginBase {
         return $l != $r;
       },
       'contains' => function ($l, $r) {
-        return stripos($l, $r) !== FALSE;
+        return stripos((!empty($l) ? $l : ''), $r) !== FALSE;
       },
       'starts' => function ($l, $r) {
-        return strpos($l, $r) === 0;
+        return strpos((!empty($l) ? $l : ''), $r) === 0;
       },
       'not_starts' => function ($l, $r) {
-        return strpos($l, $r) !== 0;
+        return strpos((!empty($l) ? $l : ''), $r) !== 0;
       },
       'ends' => function ($l, $r) {
         $len = strlen($r);
@@ -323,7 +323,7 @@ class ViewsJsonQuery extends QueryPluginBase {
         return $len > 0 ? substr($l, -$len) !== $r : TRUE;
       },
       'not' => function ($l, $r) {
-        return stripos($l, $r) === FALSE;
+        return stripos((!empty($l) ? $l : ''), $r) === FALSE;
       },
       'shorterthan' => function ($l, $r) {
         return strlen($l) < $r;