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NetworkManager/shared/nm-std-aux/nm-std-aux.h
Thomas Haller 6feab75447 shared: add nm_steal_pointer()/nm_clear_free() to "nm-std-aux.h" 
There is the team of nm_auto*, nm_clear_pointer() and nm_steal_pointer().
These goes nicely together so that an autovariable owns a resource,
to free it (clear) and to transfer ownership (steal).

We have these also in glib, but we certainly also need it if we don't
have glib because that very much goes together with nm_auto*. Add it.
2020-07-07 22:32:35 +02:00

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// SPDX-License-Identifier: LGPL-2.1+
#ifndef __NM_STD_AUX_H__
#define __NM_STD_AUX_H__
#include <assert.h>
#include <string.h>
#include <stdbool.h>
/*****************************************************************************/
#define _nm_packed __attribute__ ((__packed__))
#define _nm_unused __attribute__ ((__unused__))
#define _nm_used __attribute__ ((__used__))
#define _nm_pure __attribute__ ((__pure__))
#define _nm_const __attribute__ ((__const__))
#define _nm_printf(a,b) __attribute__ ((__format__ (__printf__, a, b)))
#define _nm_align(s) __attribute__ ((__aligned__ (s)))
#define _nm_section(s) __attribute__ ((__section__ (s)))
#define _nm_alignof(type) __alignof (type)
#define _nm_alignas(type) _nm_align (_nm_alignof (type))
#define nm_auto(fcn) __attribute__ ((__cleanup__(fcn)))
/* This is required to make LTO working.
*
* See https://gitlab.freedesktop.org/NetworkManager/NetworkManager/merge_requests/76#note_112694
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=48200#c28
*/
#ifndef __clang__
#define _nm_externally_visible __attribute__ ((__externally_visible__))
#else
#define _nm_externally_visible
#endif
#if __GNUC__ >= 7
#define _nm_fallthrough __attribute__ ((__fallthrough__))
#else
#define _nm_fallthrough
#endif
/*****************************************************************************/
#ifdef thread_local
#define _nm_thread_local thread_local
/*
* Don't break on glibc < 2.16 that doesn't define __STDC_NO_THREADS__
* see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53769
*/
#elif __STDC_VERSION__ >= 201112L && !(defined(__STDC_NO_THREADS__) || (defined(__GNU_LIBRARY__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 16))
#define _nm_thread_local _Thread_local
#else
#define _nm_thread_local __thread
#endif
/*****************************************************************************/
#define NM_PASTE_ARGS(identifier1,identifier2) identifier1 ## identifier2
#define NM_PASTE(identifier1,identifier2) NM_PASTE_ARGS (identifier1, identifier2)
/* Taken from systemd's UNIQ_T and UNIQ macros. */
#define NM_UNIQ_T(x, uniq) NM_PASTE(__unique_prefix_, NM_PASTE(x, uniq))
#define NM_UNIQ __COUNTER__
/*****************************************************************************/
#define _NM_BOOLEAN_EXPR_IMPL(v, expr) \
({ \
int NM_UNIQ_T(V, v); \
\
if (expr) \
NM_UNIQ_T(V, v) = 1; \
else \
NM_UNIQ_T(V, v) = 0; \
NM_UNIQ_T(V, v); \
})
#define NM_BOOLEAN_EXPR(expr) _NM_BOOLEAN_EXPR_IMPL (NM_UNIQ, expr)
#if defined(__GNUC__) && (__GNUC__ > 2) && defined(__OPTIMIZE__)
#define NM_LIKELY(expr) (__builtin_expect (NM_BOOLEAN_EXPR (expr), 1))
#define NM_UNLIKELY(expr) (__builtin_expect (NM_BOOLEAN_EXPR (expr), 0))
#else
#define NM_LIKELY(expr) NM_BOOLEAN_EXPR (expr)
#define NM_UNLIKELY(expr) NM_BOOLEAN_EXPR (expr)
#endif
/*****************************************************************************/
/* glib/C provides the following kind of assertions:
* - assert() -- disable with NDEBUG
* - g_return_if_fail() -- disable with G_DISABLE_CHECKS
* - g_assert() -- disable with G_DISABLE_ASSERT
* but they are all enabled by default and usually even production builds have
* these kind of assertions enabled. It also means, that disabling assertions
* is an untested configuration, and might have bugs.
*
* Add our own assertion macro nm_assert(), which is disabled by default and must
* be explicitly enabled. They are useful for more expensive checks or checks that
* depend less on runtime conditions (that is, are generally expected to be true). */
#ifndef NM_MORE_ASSERTS
#define NM_MORE_ASSERTS 0
#endif
#ifndef _nm_assert_call
#define _nm_assert_call(cond) assert(cond)
#define _nm_assert_call_not_reached() assert(0)
#endif
#if NM_MORE_ASSERTS
#define nm_assert(cond) do { _nm_assert_call (cond); } while (0)
#define nm_assert_se(cond) do { if (NM_LIKELY (cond)) { ; } else { _nm_assert_call (0 && (cond)); } } while (0)
#define nm_assert_not_reached() do { _nm_assert_call_not_reached (); } while (0)
#else
#define nm_assert(cond) do { if (0) { if (cond) { } } } while (0)
#define nm_assert_se(cond) do { if (NM_LIKELY (cond)) { ; } } while (0)
#define nm_assert_not_reached() do { ; } while (0)
#endif
#define NM_STATIC_ASSERT(cond) static_assert(cond, "")
#define NM_STATIC_ASSERT_EXPR(cond) ({ NM_STATIC_ASSERT (cond); 1; })
/*****************************************************************************/
#define NM_N_ELEMENTS(arr) (sizeof (arr) / sizeof ((arr)[0]))
/*****************************************************************************/
/* glib's MIN()/MAX() macros don't have function-like behavior, in that they evaluate
* the argument possibly twice.
*
* Taken from systemd's MIN()/MAX() macros. */
#define NM_MIN(a, b) __NM_MIN(NM_UNIQ, a, NM_UNIQ, b)
#define __NM_MIN(aq, a, bq, b) \
({ \
typeof (a) NM_UNIQ_T(A, aq) = (a); \
typeof (b) NM_UNIQ_T(B, bq) = (b); \
((NM_UNIQ_T(A, aq) < NM_UNIQ_T(B, bq)) ? NM_UNIQ_T(A, aq) : NM_UNIQ_T(B, bq)); \
})
#define NM_MAX(a, b) __NM_MAX(NM_UNIQ, a, NM_UNIQ, b)
#define __NM_MAX(aq, a, bq, b) \
({ \
typeof (a) NM_UNIQ_T(A, aq) = (a); \
typeof (b) NM_UNIQ_T(B, bq) = (b); \
((NM_UNIQ_T(A, aq) > NM_UNIQ_T(B, bq)) ? NM_UNIQ_T(A, aq) : NM_UNIQ_T(B, bq)); \
})
#define NM_CLAMP(x, low, high) __NM_CLAMP(NM_UNIQ, x, NM_UNIQ, low, NM_UNIQ, high)
#define __NM_CLAMP(xq, x, lowq, low, highq, high) \
({ \
typeof(x)NM_UNIQ_T(X,xq) = (x); \
typeof(low) NM_UNIQ_T(LOW,lowq) = (low); \
typeof(high) NM_UNIQ_T(HIGH,highq) = (high); \
\
( (NM_UNIQ_T(X,xq) > NM_UNIQ_T(HIGH,highq)) \
? NM_UNIQ_T(HIGH,highq) \
: (NM_UNIQ_T(X,xq) < NM_UNIQ_T(LOW,lowq)) \
? NM_UNIQ_T(LOW,lowq) \
: NM_UNIQ_T(X,xq)); \
})
#define NM_MAX_WITH_CMP(cmp, a, b) \
({ \
typeof (a) _a = (a); \
typeof (b) _b = (b); \
\
( ((cmp (_a, _b)) >= 0) \
? _a \
: _b); \
})
/* evaluates to (void) if _A or _B are not constant or of different types */
#define NM_CONST_MAX(_A, _B) \
(__builtin_choose_expr (( __builtin_constant_p (_A) \
&& __builtin_constant_p (_B) \
&& __builtin_types_compatible_p (typeof (_A), typeof (_B))), \
((_A) > (_B)) ? (_A) : (_B), \
((void) 0)))
/*****************************************************************************/
#define NM_SWAP(a, b) \
do { \
typeof (a) _tmp; \
\
_tmp = (a); \
(a) = (b); \
(b) = _tmp; \
} while (0)
/*****************************************************************************/
/* macro to return strlen() of a compile time string. */
#define NM_STRLEN(str) ( sizeof (""str"") - 1u )
/* returns the length of a NULL terminated array of pointers,
* like g_strv_length() does. The difference is:
* - it operates on arrays of pointers (of any kind, requiring no cast).
* - it accepts NULL to return zero. */
#define NM_PTRARRAY_LEN(array) \
({ \
typeof (*(array)) *const _array = (array); \
size_t _n = 0; \
\
if (_array) { \
_nm_unused const void * _type_check_is_pointer = _array[0]; \
\
while (_array[_n]) \
_n++; \
} \
_n; \
})
/*****************************************************************************/
static inline int
nm_strcmp0 (const char *s1, const char *s2)
{
int c;
/* like g_strcmp0(), but this is inlinable.
*
* Also, it is guaranteed to return either -1, 0, or 1. */
if (s1 == s2)
return 0;
if (!s1)
return -1;
if (!s2)
return 1;
c = strcmp (s1, s2);
if (c < 0)
return -1;
if (c > 0)
return 1;
return 0;
}
static inline int
nm_streq (const char *s1, const char *s2)
{
return strcmp (s1, s2) == 0;
}
static inline int
nm_streq0 (const char *s1, const char *s2)
{
return (s1 == s2)
|| (s1 && s2 && strcmp (s1, s2) == 0);
}
#define NM_STR_HAS_PREFIX(str, prefix) \
({ \
const char *const _str_has_prefix = (str); \
\
nm_assert (strlen (prefix) == NM_STRLEN (prefix)); \
\
_str_has_prefix \
&& (strncmp (_str_has_prefix, ""prefix"", NM_STRLEN (prefix)) == 0); \
})
#define NM_STR_HAS_SUFFIX(str, suffix) \
({ \
const char *const _str_has_suffix = (str); \
size_t _l; \
\
nm_assert (strlen (suffix) == NM_STRLEN (suffix)); \
\
( _str_has_suffix \
&& ((_l = strlen (_str_has_suffix)) >= NM_STRLEN (suffix)) \
&& (memcmp (&_str_has_suffix[_l - NM_STRLEN (suffix)], \
""suffix"", \
NM_STRLEN (suffix)) == 0)); \
})
/* whether @str starts with the string literal @prefix and is followed by
* some other text. It is like NM_STR_HAS_PREFIX() && !nm_streq() together. */
#define NM_STR_HAS_PREFIX_WITH_MORE(str, prefix) \
({ \
const char *const _str_has_prefix_with_more = (str); \
\
NM_STR_HAS_PREFIX (_str_has_prefix_with_more, ""prefix"") \
&& _str_has_prefix_with_more[NM_STRLEN (prefix)] != '\0'; \
})
/*****************************************************************************/
#define _NM_IN_SET_EVAL_1( op, _x, y) (_x == (y))
#define _NM_IN_SET_EVAL_2( op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_1 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_3( op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_2 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_4( op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_3 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_5( op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_4 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_6( op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_5 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_7( op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_6 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_8( op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_7 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_9( op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_8 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_10(op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_9 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_11(op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_10 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_12(op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_11 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_13(op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_12 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_14(op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_13 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_15(op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_14 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_16(op, _x, y, ...) (_x == (y)) op _NM_IN_SET_EVAL_15 (op, _x, __VA_ARGS__)
#define _NM_IN_SET_EVAL_N2(op, _x, n, ...) (_NM_IN_SET_EVAL_##n(op, _x, __VA_ARGS__))
#define _NM_IN_SET_EVAL_N(op, type, x, n, ...) \
({ \
type _x = (x); \
\
/* trigger a -Wenum-compare warning */ \
nm_assert (true || _x == (x)); \
\
!!_NM_IN_SET_EVAL_N2(op, _x, n, __VA_ARGS__); \
})
#define _NM_IN_SET(op, type, x, ...) _NM_IN_SET_EVAL_N(op, type, x, NM_NARG (__VA_ARGS__), __VA_ARGS__)
/* Beware that this does short-circuit evaluation (use "||" instead of "|")
* which has a possibly unexpected non-function-like behavior.
* Use NM_IN_SET_SE if you need all arguments to be evaluated. */
#define NM_IN_SET(x, ...) _NM_IN_SET(||, typeof (x), x, __VA_ARGS__)
/* "SE" stands for "side-effect". Contrary to NM_IN_SET(), this does not do
* short-circuit evaluation, which can make a difference if the arguments have
* side-effects. */
#define NM_IN_SET_SE(x, ...) _NM_IN_SET(|, typeof (x), x, __VA_ARGS__)
/* the *_TYPED forms allow to explicitly select the type of "x". This is useful
* if "x" doesn't support typeof (bitfields) or you want to gracefully convert
* a type using automatic type conversion rules (but not forcing the conversion
* with a cast). */
#define NM_IN_SET_TYPED(type, x, ...) _NM_IN_SET(||, type, x, __VA_ARGS__)
#define NM_IN_SET_SE_TYPED(type, x, ...) _NM_IN_SET(|, type, x, __VA_ARGS__)
/*****************************************************************************/
static inline int
_NM_IN_STRSET_streq (const char *x, const char *s)
{
return s && strcmp (x, s) == 0;
}
#define _NM_IN_STRSET_EVAL_1( op, _x, y) _NM_IN_STRSET_streq (_x, y)
#define _NM_IN_STRSET_EVAL_2( op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_1 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_3( op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_2 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_4( op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_3 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_5( op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_4 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_6( op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_5 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_7( op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_6 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_8( op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_7 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_9( op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_8 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_10(op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_9 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_11(op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_10 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_12(op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_11 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_13(op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_12 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_14(op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_13 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_15(op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_14 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_16(op, _x, y, ...) _NM_IN_STRSET_streq (_x, y) op _NM_IN_STRSET_EVAL_15 (op, _x, __VA_ARGS__)
#define _NM_IN_STRSET_EVAL_N2(op, _x, n, ...) (_NM_IN_STRSET_EVAL_##n(op, _x, __VA_ARGS__))
#define _NM_IN_STRSET_EVAL_N(op, x, n, ...) \
({ \
const char *_x = (x); \
( ((_x == NULL) && _NM_IN_SET_EVAL_N2 (op, ((const char *) NULL), n, __VA_ARGS__)) \
|| ((_x != NULL) && _NM_IN_STRSET_EVAL_N2 (op, _x, n, __VA_ARGS__)) \
); \
})
/* Beware that this does short-circuit evaluation (use "||" instead of "|")
* which has a possibly unexpected non-function-like behavior.
* Use NM_IN_STRSET_SE if you need all arguments to be evaluated. */
#define NM_IN_STRSET(x, ...) _NM_IN_STRSET_EVAL_N(||, x, NM_NARG (__VA_ARGS__), __VA_ARGS__)
/* "SE" stands for "side-effect". Contrary to NM_IN_STRSET(), this does not do
* short-circuit evaluation, which can make a difference if the arguments have
* side-effects. */
#define NM_IN_STRSET_SE(x, ...) _NM_IN_STRSET_EVAL_N(|, x, NM_NARG (__VA_ARGS__), __VA_ARGS__)
/*****************************************************************************/
#define NM_STRCHAR_ALL(str, ch_iter, predicate) \
({ \
int _val = true; \
const char *_str = (str); \
\
if (_str) { \
for (;;) { \
const char ch_iter = _str[0]; \
\
if (ch_iter != '\0') { \
if (predicate) {\
_str++; \
continue; \
} \
_val = false; \
} \
break; \
} \
} \
_val; \
})
#define NM_STRCHAR_ANY(str, ch_iter, predicate) \
({ \
int _val = false; \
const char *_str = (str); \
\
if (_str) { \
for (;;) { \
const char ch_iter = _str[0]; \
\
if (ch_iter != '\0') { \
if (predicate) { \
; \
} else { \
_str++; \
continue; \
} \
_val = true; \
} \
break; \
} \
} \
_val; \
})
/*****************************************************************************/
/* Note: @value is only evaluated when *out_val is present.
* Thus,
* NM_SET_OUT (out_str, g_strdup ("hallo"));
* does the right thing.
*/
#define NM_SET_OUT(out_val, value) \
({ \
typeof(*(out_val)) *_out_val = (out_val); \
\
if (_out_val) { \
*_out_val = (value); \
} \
\
(!!_out_val); \
})
/*****************************************************************************/
#define NM_AUTO_DEFINE_FCN_VOID(CastType, name, func) \
static inline void name (void *v) \
{ \
func (*((CastType *) v)); \
}
#define NM_AUTO_DEFINE_FCN_VOID0(CastType, name, func) \
static inline void name (void *v) \
{ \
if (*((CastType *) v)) \
func (*((CastType *) v)); \
}
#define NM_AUTO_DEFINE_FCN(Type, name, func) \
static inline void name (Type *v) \
{ \
func (*v); \
}
#define NM_AUTO_DEFINE_FCN0(Type, name, func) \
static inline void name (Type *v) \
{ \
if (*v) \
func (*v); \
}
/*****************************************************************************/
/**
* nm_auto_free:
*
* Call free() on a variable location when it goes out of scope.
* This is for pointers that are allocated with malloc() instead of
* g_malloc().
*
* In practice, since glib 2.45, g_malloc()/g_free() always wraps malloc()/free().
* See bgo#751592. In that case, it would be safe to free pointers allocated with
* malloc() with gs_free or g_free().
*
* However, let's never mix them. To free malloc'ed memory, always use
* free() or nm_auto_free.
*/
NM_AUTO_DEFINE_FCN_VOID0 (void *, _nm_auto_free_impl, free)
#define nm_auto_free nm_auto(_nm_auto_free_impl)
/*****************************************************************************/
#define nm_clear_pointer(pp, destroy) \
({ \
typeof (*(pp)) *_pp = (pp); \
typeof (*_pp) _p; \
int _changed = false; \
\
if ( _pp \
&& (_p = *_pp)) { \
_nm_unused const void *_p_check_is_pointer = _p; \
\
*_pp = NULL; \
\
/* g_clear_pointer() assigns @destroy first to a local variable, so that
* you can call "g_clear_pointer (pp, (GDestroyNotify) destroy);" without
* gcc emitting a warning. We don't do that, hence, you cannot cast
* "destroy" first.
*
* On the upside: you are not supposed to cast fcn, because the pointer
* types are preserved. If you really need a cast, you should cast @pp.
* But that is hardly ever necessary. */ \
(destroy) (_p); \
\
_changed = true; \
} \
_changed; \
})
#define nm_clear_free(pp) nm_clear_pointer (pp, free)
/*****************************************************************************/
static inline void *
_nm_steal_pointer (void *pp)
{
void **ptr = (void **) pp;
void *ref;
ref = *ptr;
*ptr = NULL;
return ref;
}
#define nm_steal_pointer(pp) \
((typeof (*(pp))) _nm_steal_pointer (pp))
#endif /* __NM_STD_AUX_H__ */
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