From cc351812b0109898a5d391ce21326de264d1443f Mon Sep 17 00:00:00 2001
From: Qing Zhang <qing.zhang@block.one>
Date: Mon, 26 Oct 2020 14:00:47 -0700
Subject: [PATCH] add KV Table iterator bool operator

---
 libraries/eosiolib/contracts/eosio/key_value.hpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libraries/eosiolib/contracts/eosio/key_value.hpp b/libraries/eosiolib/contracts/eosio/key_value.hpp
index 375ebbf5d0..17b7debd75 100644
--- a/libraries/eosiolib/contracts/eosio/key_value.hpp
+++ b/libraries/eosiolib/contracts/eosio/key_value.hpp
@@ -444,6 +444,8 @@ namespace internal {
          return eosio::key_type{(char*)buffer, actual_value_size};
       }
 
+      bool valid() const { return itr_stat == status::iterator_ok; }
+
    protected:
       uint32_t itr;
       status itr_stat;
@@ -569,6 +571,10 @@ class table : internal::table_base {
       bool operator>=(const iterator& b) const {
          return base_iterator::compare(b) >= 0;
       }
+
+      explicit operator bool() const {
+         return this->valid();
+      }
    };
 
    class reverse_iterator : public base_iterator {