/* $NetBSD: ntp_assert.h,v 1.6 2020/05/25 20:47:19 christos Exp $ */

/* $NetBSD: ntp_assert.h,v 1.6 2020/05/25 20:47:19 christos Exp $ */

/*
* ntp_assert.h - design by contract stuff
*
* example:
*
* int foo(char *a) {
* int result;
* int value;
*
* REQUIRE(a != NULL);
* ...
* bar(&value);
* INSIST(value > 2);
* ...
*
* ENSURE(result != 12);
* return result;
* }
*
* open question: when would we use INVARIANT()?
*
* For cases where the overhead for non-debug builds is deemed too high,
* use DEBUG_REQUIRE(), DEBUG_INSIST(), DEBUG_ENSURE(), and/or
* DEBUG_INVARIANT().
*/

#ifndef NTP_ASSERT_H
#define NTP_ASSERT_H

# ifdef CALYSTO
/* see: http://www.domagoj-babic.com/index.php/ResearchProjects/Calysto */

extern void calysto_assume(unsigned char cnd); /* assume this always holds */
extern void calysto_assert(unsigned char cnd); /* check whether this holds */
#define ALWAYS_REQUIRE(x) calysto_assert(x)
#define ALWAYS_INSIST(x) calysto_assume(x) /* DLH calysto_assert()? */
#define ALWAYS_INVARIANT(x) calysto_assume(x)
#define ALWAYS_ENSURE(x) calysto_assert(x)

/* # elif defined(__COVERITY__) */
/*
* DH: try letting coverity scan our actual assertion macros, now that
* isc_assertioncallback_t is marked __attribute__ __noreturn__.
*/

/*
* Coverity has special knowledge that assert(x) terminates the process
* if x is not true. Rather than teach it about our assertion macros,
* just use the one it knows about for Coverity Prevent scans. This
* means our assertion code (and ISC's) escapes Coverity analysis, but
* that seems to be a reasonable trade-off.
*/

/*
#define ALWAYS_REQUIRE(x) assert(x)
#define ALWAYS_INSIST(x) assert(x)
#define ALWAYS_INVARIANT(x) assert(x)
#define ALWAYS_ENSURE(x) assert(x)
*/

#elif defined(__FLEXELINT__)

#include <assert.h>

#define ALWAYS_REQUIRE(x) assert(x)
#define ALWAYS_INSIST(x) assert(x)
#define ALWAYS_INVARIANT(x) assert(x)
#define ALWAYS_ENSURE(x) assert(x)

# else /* neither Calysto, Coverity or FlexeLint */

#include "isc/assertions.h"

#define ALWAYS_REQUIRE(x) ISC_REQUIRE(x)
#define ALWAYS_INSIST(x) ISC_INSIST(x)
#define ALWAYS_INVARIANT(x) ISC_INVARIANT(x)
#define ALWAYS_ENSURE(x) ISC_ENSURE(x)

# endif /* neither Coverity nor Calysto */

#define REQUIRE(x) ALWAYS_REQUIRE(x)
#define INSIST(x) ALWAYS_INSIST(x)
#define INVARIANT(x) ALWAYS_INVARIANT(x)
#define ENSURE(x) ALWAYS_ENSURE(x)

/*
* We initially used NTP_REQUIRE() instead of REQUIRE() etc, but that
* is unneccesarily verbose, as libisc use of REQUIRE() etc shows.
*/

# ifdef DEBUG
#define DEBUG_REQUIRE(x) REQUIRE(x)
#define DEBUG_INSIST(x) INSIST(x)
#define DEBUG_INVARIANT(x) INVARIANT(x)
#define DEBUG_ENSURE(x) ENSURE(x)
# else
#define DEBUG_REQUIRE(x) do {} while (FALSE)
#define DEBUG_INSIST(x) do {} while (FALSE)
#define DEBUG_INVARIANT(x) do {} while (FALSE)
#define DEBUG_ENSURE(x) do {} while (FALSE)
# endif

#endif /* NTP_ASSERT_H */