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/* reference counting macros
*
* Copyright (C) 2019 Andrew Cagney
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <https://www.gnu.org/licenses/gpl2.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
*/
#ifndef REFCNT_H
#define REFCNT_H
#include <stdbool.h>
#include "lswcdefs.h" /* for MUST_USE_RESULT */
#include "where.h"
struct logger;
struct refcnt_base {
const char *what;
};
typedef struct refcnt {
volatile unsigned count;
const struct refcnt_base *base;
} refcnt_t;
/*
* Allocate the structure (plus extra) initializing the refcnt.
*
* On return the object has a reference count of one and all other
* fields are zero.
*
* Note: any over-allocated memory is _NOT_ aligned.
*/
void refcnt_init(const void *pointer, struct refcnt *refcnt,
const struct refcnt_base *base, where_t where);
#define refcnt_overalloc(THING, EXTRA, WHERE) \
({ \
static const struct refcnt_base b_ = { \
.what = #THING, \
}; \
THING *t_ = overalloc_thing(THING, EXTRA); \
refcnt_init(t_, &t_->refcnt, &b_, WHERE); \
t_; \
})
#define refcnt_alloc(THING, WHERE) \
refcnt_overalloc(THING, /*extra*/0, WHERE)
/* look at refcnt atomically */
unsigned refcnt_peek_where(const void *pointer,
const refcnt_t *refcnt,
const struct logger *owner,
where_t where);
#define refcnt_peek(OBJ, OWNER) \
({ \
typeof(OBJ) o_ = OBJ; /* evaluate once */ \
(o_ == NULL ? 0 : /* a NULL pointer has no references */ \
refcnt_peek_where(o_, &o_->refcnt, OWNER, HERE)); \
})
/*
* Add a reference.
*/
void refcnt_addref_where(const char *what, const void *pointer,
refcnt_t *refcnt,
const struct logger *logger,
const struct logger *new_owner,
where_t where);
/* old */
#define addref_where(OBJ, WHERE) \
({ \
typeof(OBJ) o_ = OBJ; /* evaluate once */ \
if (o_ != NULL) { \
refcnt_addref_where(#OBJ, o_, \
&o_->refcnt, \
NULL, NULL, WHERE); \
} \
o_; /* result */ \
})
/* new */
#define laddref_where(OBJ, OWNER, WHERE) \
({ \
typeof(OBJ) o_ = OBJ; /* evaluate once */ \
if (o_ != NULL) { \
refcnt_addref_where(#OBJ, o_, \
&o_->refcnt, \
o_->logger, \
OWNER, WHERE); \
} \
o_; /* result */ \
})
/*
* Delete a reference.
*
* Returns a non-NULL pointer to the object when it is the last
* reference and needs to be pfree()ed.
*/
void *refcnt_delref_where(const char *what, void *pointer,
struct refcnt *refcnt,
const struct logger *logger,
const struct logger *owner,
where_t where) MUST_USE_RESULT;
#define delref_where(OBJP, LOGGER, WHERE) \
({ \
typeof(OBJP) op_ = OBJP; \
typeof(*OBJP) o_ = *op_; \
*op_ = NULL; /* always kill pointer; and early */ \
if (o_ != NULL) { \
o_ = refcnt_delref_where(#OBJP, o_, \
&o_->refcnt, \
LOGGER, NULL, WHERE); \
} \
o_; /* NULL or last OBJ */ \
})
#define ldelref_where(OBJP, OWNER, WHERE) \
({ \
typeof(OBJP) op_ = OBJP; \
typeof(*OBJP) o_ = *op_; \
*op_ = NULL; /* always kill pointer; and early */ \
if (o_ != NULL) { \
o_ = refcnt_delref_where(#OBJP, o_, \
&o_->refcnt, \
o_->logger, \
OWNER, WHERE); \
} \
o_; /* NULL or last OBJ */ \
})
/*
* For code wanting to use refcnt checks but with normal allocs.
*/
void ldbg_alloc(const struct logger *logger, const char *what, const void *pointer, where_t where);
void ldbg_free(const struct logger *logger, const char *what, const void *pointer, where_t where);
void ldbg_addref_where(const struct logger *logger, const char *what, const void *pointer, where_t where);
void ldbg_delref_where(const struct logger *logger, const char *what, const void *pointer, where_t where);
void dbg_alloc(const char *what, const void *pointer, where_t where);
void dbg_free(const char *what, const void *pointer, where_t where);
#endif
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