CONC-691: Obtain sql statement from statement handle

Added an option STMT_ATTR_SQL_STATEMENT in API function
mariadb_stmt_attr_get which returns a MARIADB_CONST_STRING
structure which contains SQL statement from last
mysql_stmt_prepare() call.

include/mariadb_stmt.h

@@ -69,7 +69,8 @@ enum enum_stmt_attr_type
   STMT_ATTR_STATE,
   STMT_ATTR_CB_USER_DATA,
   STMT_ATTR_CB_PARAM,
-  STMT_ATTR_CB_RESULT
+  STMT_ATTR_CB_RESULT,
+  STMT_ATTR_SQL_STATEMENT
 };
 
 enum enum_cursor_type
@@ -204,6 +205,7 @@ struct st_mysql_stmt
   ps_result_callback result_callback;
   ps_param_callback param_callback;
   size_t request_length;
+  MARIADB_CONST_STRING sql;
 };
 
 typedef void (*ps_field_fetch_func)(MYSQL_BIND *r_param, const MYSQL_FIELD * field, unsigned char **row);

libmariadb/mariadb_lib.c

@@ -971,7 +971,7 @@ static MARIADB_CONST_STRING null_const_string= {0,0};
 /***************************************************************************
 ** Allocate a string copy on memroot
 ***************************************************************************/
-static MARIADB_CONST_STRING ma_const_string_copy_root(MA_MEM_ROOT *memroot,
+MARIADB_CONST_STRING ma_const_string_copy_root(MA_MEM_ROOT *memroot,
                                                       const char *str,
                                                       size_t length)
 {

libmariadb/mariadb_stmt.c

@@ -80,6 +80,9 @@ typedef struct
 } MADB_STMT_EXTENSION;
 
 static my_bool net_stmt_close(MYSQL_STMT *stmt, my_bool remove);
+extern MARIADB_CONST_STRING ma_const_string_copy_root(MA_MEM_ROOT *memroot,
+                                                      const char *str,
+                                                      size_t length);
 
 static my_bool is_not_null= 0;
 static my_bool is_null= 1;
@@ -1186,6 +1189,9 @@ unsigned long long STDCALL mysql_stmt_affected_rows(MYSQL_STMT *stmt)
 my_bool STDCALL mysql_stmt_attr_get(MYSQL_STMT *stmt, enum enum_stmt_attr_type attr_type, void *value)
 {
   switch (attr_type) {
+    case STMT_ATTR_SQL_STATEMENT:
+      *(MARIADB_CONST_STRING *)value= stmt->sql;
+      break;
     case STMT_ATTR_STATE:
       *(enum mysql_stmt_state *)value= stmt->state;
       break;
@@ -1841,6 +1847,8 @@ int STDCALL mysql_stmt_prepare(MYSQL_STMT *stmt, const char *query, unsigned lon
                                          sizeof(stmt_id), 1, stmt))
       goto fail;
   }
+  stmt->sql= ma_const_string_copy_root(&stmt->mem_root, query, length);
+
   if (mysql->methods->db_command(mysql, COM_STMT_PREPARE, query, length, 1, stmt))
     goto fail;
 
@@ -2398,10 +2406,16 @@ MYSQL_RES * STDCALL mysql_stmt_result_metadata(MYSQL_STMT *stmt)
 
 my_bool STDCALL mysql_stmt_reset(MYSQL_STMT *stmt)
 {
+  my_bool rc= 0;
   if (stmt->stmt_id > 0 &&
       stmt->stmt_id != (unsigned long) -1)
-    return mysql_stmt_internal_reset(stmt, 0);
-  return 0;
+    rc= mysql_stmt_internal_reset(stmt, 0);
+
+  /* clear last sql statement */
+  stmt->sql.str= 0;
+  stmt->sql.length= 0;
+
+  return rc;
 }
 
 const char * STDCALL mysql_stmt_sqlstate(MYSQL_STMT *stmt)

unittest/libmariadb/ps.c

@@ -5224,7 +5224,46 @@ end:
   return error ? FAIL : OK;
 }
 
+static int test_conc691(MYSQL *mysql)
+{
+  MYSQL_STMT *stmt= mysql_stmt_init(mysql);
+  MARIADB_CONST_STRING sql;
+  const char *sql_stmt[]= {"SELECT 'test' FROM DUAL", "This will return an error", "SELECT 1 FROM DUAL"};
+  int rc, i;
+
+  rc= mysql_stmt_attr_get(stmt, STMT_ATTR_SQL_STATEMENT, &sql);
+  check_stmt_rc(rc, stmt);
+
+  FAIL_IF(sql.str, "Expected empty SQL string");
+  FAIL_IF(sql.length, "Expected length=0");
+
+
+  for (i=0; i < 3; i++)
+  {
+    rc= mysql_stmt_prepare(stmt, SL(sql_stmt[i]));
+
+    rc= mysql_stmt_attr_get(stmt, STMT_ATTR_SQL_STATEMENT, &sql);
+    check_stmt_rc(rc, stmt);
+
+    FAIL_IF(strncmp(sql.str, sql_stmt[i], strlen(sql_stmt[i])), "Wrong SQL statement");
+    FAIL_IF(sql.length != strlen(sql_stmt[i]), "Wrong statement length");
+  }
+
+  rc= mysql_stmt_reset(stmt);
+  check_stmt_rc(rc, stmt);
+
+  rc= mysql_stmt_attr_get(stmt, STMT_ATTR_SQL_STATEMENT, &sql);
+  check_stmt_rc(rc, stmt);
+
+  FAIL_IF(sql.str, "Expected empty SQL string");
+  FAIL_IF(sql.length, "Expected length=0");
+
+  mysql_stmt_close(stmt);
+  return OK;
+}
+
 struct my_tests_st my_tests[] = {
+  {"test_conc691", test_conc691, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_conc565", test_conc565, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_conc349", test_conc349, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_prepare_error", test_prepare_error, TEST_CONNECTION_NEW, 0, NULL, NULL},