[refcnt] Check reference validity on each use of ref_get() and ref_put()

Check that the reference count is valid (i.e. non-negative) on each
call to ref_get() and ref_put(), using an assert() at the point of
use.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2010-11-05 22:24:46 +00:00
parent fc69ab94d9
commit 6e41f2cf18
2 changed files with 52 additions and 12 deletions

View File

@@ -9,6 +9,9 @@
FILE_LICENCE ( GPL2_OR_LATER );
#include <stddef.h>
#include <assert.h>
/**
* A reference counter
*
@@ -26,7 +29,7 @@ struct refcnt {
* When this count is decremented below zero, the free()
* method will be called.
*/
int refcnt;
int count;
/** Free containing object
*
* This method is called when the reference count is
@@ -75,8 +78,37 @@ ref_init ( struct refcnt *refcnt,
.free = free_fn, \
}
extern struct refcnt * ref_get ( struct refcnt *refcnt );
extern void ref_put ( struct refcnt *refcnt );
extern void ref_increment ( struct refcnt *refcnt );
extern void ref_decrement ( struct refcnt *refcnt );
/**
* Get additional reference to object
*
* @v refcnt Reference counter, or NULL
* @ret refcnt Reference counter
*
* If @c refcnt is NULL, no action is taken.
*/
#define ref_get( refcnt ) ( { \
if ( refcnt ) \
assert ( (refcnt)->count >= 0 ); \
ref_increment ( refcnt ); \
(refcnt); } )
/**
* Drop reference to object
*
* @v refcnt Reference counter, or NULL
* @ret refcnt Reference counter
*
* If @c refcnt is NULL, no action is taken.
*/
#define ref_put( refcnt ) do { \
if ( refcnt ) \
assert ( (refcnt)->count >= 0 ); \
ref_decrement ( refcnt ); \
} while ( 0 )
extern void ref_no_free ( struct refcnt *refcnt );
#endif /* _IPXE_REFCNT_H */