Commit 49976947 authored by Ondřej Surý's avatar Ondřej Surý

Restore DbC checks in isc_refcount API

The isc_refcount API that provides reference counting lost DbC checks for
overflows and underflows in the isc_refcount_{increment,decrement} functions.

The commit restores the overflow check in the isc_refcount_increment and
underflows check in the isc_refcount_decrement by checking for the previous
value to not be on the boundary.
parent a910b0a8
......@@ -52,15 +52,15 @@ typedef atomic_uint_fast32_t isc_refcount_t;
* atomic_load_explicit() by casting to uint_fast32_t.
*/
#define isc_refcount_current(target) \
(uint_fast32_t)atomic_load_explicit(target, memory_order_acquire)
#define isc_refcount_current(target) \
(uint_fast32_t)atomic_load_acquire(target)
/** \def isc_refcount_destroy(ref)
* \brief a destructor that makes sure that all references were cleared.
* \param[in] ref pointer to reference counter.
* \returns nothing.
*/
#define isc_refcount_destroy(target) \
#define isc_refcount_destroy(target) \
ISC_REQUIRE(isc_refcount_current(target) == 0)
/** \def isc_refcount_increment0(ref)
......@@ -68,23 +68,41 @@ typedef atomic_uint_fast32_t isc_refcount_t;
* \param[in] ref pointer to reference counter.
* \returns previous value of reference counter.
*/
#define isc_refcount_increment0(target) \
isc_refcount_increment(target)
#define isc_refcount_increment0(target) \
({ \
/* cppcheck-suppress shadowVariable */ \
uint_fast32_t __v; \
__v = atomic_fetch_add_relaxed(target, 1); \
INSIST(__v < UINT32_MAX); \
__v; \
})
/** \def isc_refcount_increment(ref)
* \brief increases reference counter by 1.
* \param[in] ref pointer to reference counter.
* \returns previous value of reference counter.
*/
#define isc_refcount_increment(target) \
atomic_fetch_add_explicit(target, 1, memory_order_relaxed)
#define isc_refcount_increment(target) \
({ \
/* cppcheck-suppress shadowVariable */ \
uint_fast32_t __v; \
__v = atomic_fetch_add_relaxed(target, 1); \
INSIST(__v > 0 && __v < UINT32_MAX); \
__v; \
})
/** \def isc_refcount_decrement(ref)
* \brief decreases reference counter by 1.
* \param[in] ref pointer to reference counter.
* \returns previous value of reference counter.
*/
#define isc_refcount_decrement(target) \
atomic_fetch_sub_explicit(target, 1, memory_order_release)
#define isc_refcount_decrement(target) \
({ \
/* cppcheck-suppress shadowVariable */ \
uint_fast32_t __v; \
__v = atomic_fetch_sub_release(target, 1); \
INSIST(__v > 0); \
__v; \
})
ISC_LANG_ENDDECLS
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