rgw/s3select: limit operator bug fix

fix for json parser processing more chunks than specified in the limit

Signed-off-by: Albin Antony <albinantony20@gmail.com>

example/s3select_example.cpp

@@ -434,11 +434,15 @@ int process_json_query(const char* input_query,const char* fname)
     } 
     if(m_s3_json_object.is_sql_limit_reached())
     {
-      std::cout << "json processing reached limit " << std::endl;
       break;
     }
     read_sz = input_file_stream.read(buff.data(),BUFFER_SIZE).gcount();  
   }
+  if(m_s3_json_object.is_sql_limit_reached())
+  {
+    std::cout << "json processing reached limit " << std::endl;
+    return 0;
+  }
   try{
     	result.clear();
   	m_s3_json_object.run_s3select_on_stream(result, 0, 0, object_sz, json.output_json_format);

include/s3select.h

@@ -3193,6 +3193,7 @@ class json_object : public base_s3object
       if(is_sql_limit_reached()) 
       {
 	      status = JSON_PROCESSING_LIMIT_REACHED;//returning number since sql_execution_on_row_cb is a callback; the caller can not access the object
+        m_sql_processing_status = s3selectEngine::base_s3object::Status::LIMIT_REACHED;
       }
 
       m_sa->clear_data(); 
@@ -3201,6 +3202,10 @@ class json_object : public base_s3object
 	std::string end_of_row;
 	end_of_row = "#=== " + std::to_string(m_row_count++) + " ===#\n";
 	m_s3select_result->append(end_of_row);
+
+  if(m_is_limit_on && m_row_count == m_limit) {
+    m_sql_processing_status = s3selectEngine::base_s3object::Status::LIMIT_REACHED;
+  }
       }
       return status;
   }