From 354bb40e75d94466e91fe6960523612c9d17ccfb Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Thu, 2 Nov 2017 23:11:29 +0300
Subject: Add implementation

---
 mysql/sql/sql_cmd.h | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 mysql/sql/sql_cmd.h

(limited to 'mysql/sql/sql_cmd.h')

diff --git a/mysql/sql/sql_cmd.h b/mysql/sql/sql_cmd.h
new file mode 100644
index 0000000..8656f83
--- /dev/null
+++ b/mysql/sql/sql_cmd.h
@@ -0,0 +1,96 @@
+/* Copyright (c) 2009, 2015, Oracle and/or its affiliates. All rights reserved.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+/**
+  @file Representation of an SQL command.
+*/
+
+#ifndef SQL_CMD_INCLUDED
+#define SQL_CMD_INCLUDED
+
+#include "my_sqlcommand.h"
+#include "sql_alloc.h"
+class THD;
+
+/**
+  @class Sql_cmd - Representation of an SQL command.
+
+  This class is an interface between the parser and the runtime.
+  The parser builds the appropriate derived classes of Sql_cmd
+  to represent a SQL statement in the parsed tree.
+  The execute() method in the derived classes of Sql_cmd contain the runtime
+  implementation.
+  Note that this interface is used for SQL statements recently implemented,
+  the code for older statements tend to load the LEX structure with more
+  attributes instead.
+  Implement new statements by sub-classing Sql_cmd, as this improves
+  code modularity (see the 'big switch' in dispatch_command()), and decreases
+  the total size of the LEX structure (therefore saving memory in stored
+  programs).
+  The recommended name of a derived class of Sql_cmd is Sql_cmd_<derived>.
+
+  Notice that the Sql_cmd class should not be confused with the Statement class.
+  Statement is a class that is used to manage an SQL command or a set 
+  of SQL commands. When the SQL statement text is analyzed, the parser will
+  create one or more Sql_cmd objects to represent the actual SQL commands.
+*/
+class Sql_cmd : public Sql_alloc
+{
+private:
+  Sql_cmd(const Sql_cmd &);         // No copy constructor wanted
+  void operator=(Sql_cmd &);        // No assignment operator wanted
+
+public:
+  /**
+    @brief Return the command code for this statement
+  */
+  virtual enum_sql_command sql_command_code() const = 0;
+
+  /**
+    Execute this SQL statement.
+    @param thd the current thread.
+    @retval false on success.
+    @retval true on error
+  */
+  virtual bool execute(THD *thd) = 0;
+
+  /**
+    Command-specific reinitialization before execution of prepared statement
+
+    @see reinit_stmt_before_use()
+
+    @note Currently this function is overloaded for INSERT/REPLACE stmts only.
+
+    @param thd  Current THD.
+  */
+  virtual void cleanup(THD *thd) {}
+
+protected:
+  Sql_cmd()
+  {}
+
+  virtual ~Sql_cmd()
+  {
+    /*
+      Sql_cmd objects are allocated in thd->mem_root.
+      In MySQL, the C++ destructor is never called, the underlying MEM_ROOT is
+      simply destroyed instead.
+      Do not rely on the destructor for any cleanup.
+    */
+    DBUG_ASSERT(FALSE);
+  }
+};
+
+#endif // SQL_CMD_INCLUDED
-- 
cgit v1.1