FreeChainXenon/binutils-gdb
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Make inferior::detaching a bool, and introduce scoped_restore::release()

Browse source 
I left making inferior::detaching a bool to a separate patch, because
doing that makes a make_cleanup_restore_integer call in
infrun.c:prepare_for_detach no longer compile (passing a 'bool *' when
an 'int *' is expected).  Since we want to get rid of cleanups anyway,
I looked at converting that to a scoped_restore.  However,
prepare_for_detach wants to discard the cleanup on success, and
scoped_restore doesn't have an equivalent for that.  So I added one --
I called it "release()" because it seems like a natural fit in the way
standard components call similarly-spirited methods, and, it's also
what the proposal for a generic scope guard calls it too, AFAICS:

  http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4189.pdf

I've added some scoped_guard unit tests, while at it.

gdb/ChangeLog:
2017-04-19  Pedro Alves  <palves@redhat.com>

	* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
	unittests/scoped_restore-selftests.c.
	(SUBDIR_UNITTESTS_OBS): Add scoped_restore-selftests.o.
	* common/scoped_restore.h (scoped_restore_base): Make "class".
	(scoped_restore_base::release): New public method.
	(scoped_restore_base::scoped_restore_base): New protected ctor.
	(scoped_restore_base::m_saved_var): New protected field.
	(scoped_restore_tmpl::scoped_restore_tmpl(T*)): Initialize the
	scoped_restore_base base class instead of m_saved_var directly.
	(scoped_restore_tmpl::scoped_restore_tmpl(T*, T2)): Likewise.
	(scoped_restore_tmpl::scoped_restore_tmpl(const
	scoped_restore_tmpl<T>&)): Likewise.
	(scoped_restore_tmpl::~scoped_restore_tmpl): Use the saved_var
	method.
	(scoped_restore_tmpl::saved_var): New method.
	(scoped_restore_tmpl::m_saved_var): Delete.
	* inferior.h (inferior::detaching): Now a bool.
	* infrun.c (prepare_for_detach): Use a scoped_restore instead of a
	cleanup.
	* unittests/scoped_restore-selftests.c: New file.
This commit is contained in:
Pedro Alves 2017-04-19 13:12:23 +01:00
parent 26fcd539dd
commit 9bcb1f1630
6 changed files with 167 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

36
gdb/common/scoped_restore.h
View file

@ -21,8 +21,23 @@
#define SCOPED_RESTORE_H
/* Base class for scoped_restore_tmpl. */
struct scoped_restore_base
class scoped_restore_base
{
public:
/* This informs the (scoped_restore_tmpl<T>) dtor that you no longer
want the original value restored. */
void release () const
{ m_saved_var = NULL; }
protected:
scoped_restore_base (void *saved_var)
: m_saved_var (saved_var)
{}
/* The type-erased saved variable. This is here so that clients can
call release() on a "scoped_restore" local, which is a typedef to
a scoped_restore_base. See below. */
mutable void *m_saved_var;
};
/* A convenience typedef. Users of make_scoped_restore declare the
@ -40,7 +55,7 @@ class scoped_restore_tmpl : public scoped_restore_base
of *VAR. *VAR will be restored when this scoped_restore object
is destroyed. */
scoped_restore_tmpl (T *var)
: m_saved_var (var),
: scoped_restore_base (var),
m_saved_value (*var)
{
}
@ -52,14 +67,14 @@ class scoped_restore_tmpl : public scoped_restore_base
E.g.: T='base'; T2='derived'. */
template <typename T2>
scoped_restore_tmpl (T *var, T2 value)
: m_saved_var (var),
: scoped_restore_base (var),
m_saved_value (*var)
{
*var = value;
}
scoped_restore_tmpl (const scoped_restore_tmpl<T> &other)
: m_saved_var (other.m_saved_var),
: scoped_restore_base {other.m_saved_var},
m_saved_value (other.m_saved_value)
{
other.m_saved_var = NULL;
@ -67,18 +82,19 @@ class scoped_restore_tmpl : public scoped_restore_base
~scoped_restore_tmpl ()
{
if (m_saved_var != NULL)
*m_saved_var = m_saved_value;
if (saved_var () != NULL)
*saved_var () = m_saved_value;
}
private:
private:
/* Return a pointer to the saved variable with its type
restored. */
T *saved_var ()
{ return static_cast<T *> (m_saved_var); }
/* 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;
};