Handle DROP VIEW cleanup and robust SQL parser spans (#21)

* Handle DROP VIEW cleanup and parser span fixes

* Fix parse_select SQL length handling

Author: nicosuave

include/yardstick_ffi.h

@@ -315,6 +315,7 @@ struct YardstickMeasureAggResult {
 
 bool yardstick_has_as_measure(const char* sql);
 bool yardstick_has_aggregate(const char* sql);
+bool yardstick_drop_measure_view_from_sql(const char* sql);
 bool yardstick_has_curly_brace(const char* sql);
 bool yardstick_has_at_syntax(const char* sql);
 

src/yardstick_extension.cpp

@@ -42,6 +42,7 @@ extern "C" {
 extern "C" {
     bool yardstick_has_as_measure(const char *sql);
     bool yardstick_has_aggregate(const char *sql);
+    bool yardstick_drop_measure_view_from_sql(const char *sql);
     YardstickCreateViewResult yardstick_process_create_view(const char *sql);
     YardstickAggregateResult yardstick_expand_aggregate(const char *sql);
     void yardstick_free(char *ptr);
@@ -338,6 +339,10 @@ ParserExtensionParseResult yardstick_parse(ParserExtensionInfo *,
         sql_to_check = semantic_stripped;
     }
 
+    if (yardstick_drop_measure_view_from_sql(sql_to_check.c_str())) {
+        return ParserExtensionParseResult();
+    }
+
     // Check for AGGREGATE() function
     if (yardstick_has_aggregate(sql_to_check.c_str())) {
         YardstickAggregateResult result = yardstick_expand_aggregate(sql_to_check.c_str());