binutils-gdb/gdb/common/scoped_restore.h
Tom Tromey b7b633e9b1 Use RAII to save and restore scalars
This patch replaces many (but not all) uses of
make_cleanup_restore_integer with a simple RAII-based template class.
It also removes the similar restore_execution_direction cleanup in
favor of this new class.  Subsequent patches will replace other
similar cleanups with this class.

The class is typically instantiated using make_scoped_restore.  This
allows for template argument deduction.

2016-10-21  Tom Tromey  <tom@tromey.com>

	* common/scoped_restore.h: New file.
	* utils.h: Include scoped_restore.h.
	* top.c (execute_command_to_string): Use scoped_restore.
	* python/python.c (python_interactive_command): Use
	scoped_restore.
	(python_command, execute_gdb_command): Likewise.
	* printcmd.c (do_one_display): Use scoped_restore.
	* mi/mi-main.c (exec_continue): Use scoped_restore.
	* mi/mi-cmd-var.c (mi_cmd_var_assign): Use scoped_restore.
	* linux-fork.c (checkpoint_command): Use scoped_restore.
	* infrun.c (restore_execution_direction): Remove.
	(fetch_inferior_event): Use scoped_restore.
	* compile/compile.c (compile_file_command): Use
	scoped_restore.
	(compile_code_command, compile_print_command): Likewise.
	* cli/cli-script.c (execute_user_command): Use
	scoped_restore.
	(while_command, if_command, script_from_file): Likewise.
	* arm-tdep.c (arm_insert_single_step_breakpoint): Use
	scoped_restore.
2016-10-21 14:17:31 -06:00

100 lines
2.8 KiB
C++

/* scoped_restore, a simple class for saving and restoring a value
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of GDB.
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; either version 3 of the License, or
(at your option) any later version.
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, see <http://www.gnu.org/licenses/>. */
#ifndef SCOPED_RESTORE_H
#define SCOPED_RESTORE_H
/* Base class for scoped_restore_tmpl. */
struct scoped_restore_base
{
};
/* A convenience typedef. Users of make_scoped_restore declare the
local RAII object as having this type. */
typedef const scoped_restore_base &scoped_restore;
/* An RAII-based object that saves a variable's value, and then
restores it again when this object is destroyed. */
template<typename T>
class scoped_restore_tmpl : public scoped_restore_base
{
public:
/* Create a new scoped_restore object that saves the current value
of *VAR. *VAR will be restored when this scoped_restore object
is destroyed. */
scoped_restore_tmpl (T *var)
: m_saved_var (var),
m_saved_value (*var)
{
}
/* Create a new scoped_restore object that saves the current value
of *VAR, and sets *VAR to VALUE. *VAR will be restored when this
scoped_restore object is destroyed. */
scoped_restore_tmpl (T *var, T value)
: m_saved_var (var),
m_saved_value (*var)
{
*var = value;
}
scoped_restore_tmpl (const scoped_restore_tmpl<T> &other)
: m_saved_var (other.m_saved_var),
m_saved_value (other.m_saved_value)
{
other.m_saved_var = NULL;
}
~scoped_restore_tmpl ()
{
if (m_saved_var != NULL)
*m_saved_var = m_saved_value;
}
private:
/* No need for this. It is intentionally not defined anywhere. */
scoped_restore_tmpl &operator= (const scoped_restore_tmpl &);
/* The saved variable. */
mutable T *m_saved_var;
/* The saved value. */
const T m_saved_value;
};
/* Make a scoped_restore. This is useful because it lets template
argument deduction work. */
template<typename T>
scoped_restore_tmpl<T> make_scoped_restore (T *var)
{
return scoped_restore_tmpl<T> (var);
}
/* Make a scoped_restore. This is useful because it lets template
argument deduction work. */
template<typename T>
scoped_restore_tmpl<T> make_scoped_restore (T *var, T value)
{
return scoped_restore_tmpl<T> (var, value);
}
#endif /* SCOPED_RESTORE_H */