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author | Martin Nagy <mnagy@redhat.com> | 2009-10-06 01:34:55 +0200 |
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committer | Simo Sorce <ssorce@redhat.com> | 2009-11-06 18:06:05 -0500 |
commit | c391633a8cc03f0fc3be0b7c424b28acf94bc878 (patch) | |
tree | e06df7285138bdf7134c4750dfe7b3d3c547312d /server/util | |
parent | 5f91071ac89de679e9f36e788d7bef757ea0e4bb (diff) | |
download | sssd-c391633a8cc03f0fc3be0b7c424b28acf94bc878.tar.gz sssd-c391633a8cc03f0fc3be0b7c424b28acf94bc878.tar.bz2 sssd-c391633a8cc03f0fc3be0b7c424b28acf94bc878.zip |
Add simple reference counting wrappers for talloc
Diffstat (limited to 'server/util')
-rw-r--r-- | server/util/refcount.c | 88 | ||||
-rw-r--r-- | server/util/refcount.h | 39 |
2 files changed, 127 insertions, 0 deletions
diff --git a/server/util/refcount.c b/server/util/refcount.c new file mode 100644 index 00000000..735170d1 --- /dev/null +++ b/server/util/refcount.c @@ -0,0 +1,88 @@ +/* + SSSD + + Simple reference counting wrappers for talloc. + + Authors: + Martin Nagy <mnagy@redhat.com> + + Copyright (C) Red Hat, Inc 2009 + + 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 3 of the License, or + (at your option) any later version. + + 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. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include <talloc.h> + +#include "refcount.h" +#include "util/util.h" + +struct wrapper { + int *refcount; + void *ptr; +}; + +static int +refcount_destructor(struct wrapper *wrapper) +{ + (*wrapper->refcount)--; + if (*wrapper->refcount == 0) { + talloc_free(wrapper->ptr); + }; + + return 0; +} + +void * +_rc_alloc(const void *context, size_t size, size_t refcount_offset, + const char *type_name) +{ + struct wrapper *wrapper; + + wrapper = talloc(context, struct wrapper); + if (wrapper == NULL) { + return NULL; + } + + wrapper->ptr = talloc_named_const(NULL, size, type_name); + if (wrapper->ptr == NULL) { + talloc_free(wrapper); + return NULL; + }; + + wrapper->refcount = (int *)((char *)wrapper->ptr + refcount_offset); + *wrapper->refcount = 1; + + talloc_set_destructor(wrapper, refcount_destructor); + + return wrapper->ptr; +} + +void * +_rc_reference(const void *context, size_t refcount_offset, void *source) +{ + struct wrapper *wrapper; + + wrapper = talloc(context, struct wrapper); + if (wrapper == NULL) { + return NULL; + } + + wrapper->ptr = source; + wrapper->refcount = (int *)((char *)wrapper->ptr + refcount_offset); + (*wrapper->refcount)++; + + talloc_set_destructor(wrapper, refcount_destructor); + + return wrapper->ptr; +} diff --git a/server/util/refcount.h b/server/util/refcount.h new file mode 100644 index 00000000..cc99a173 --- /dev/null +++ b/server/util/refcount.h @@ -0,0 +1,39 @@ +#ifndef __REFCOUNT_H__ +#define __REFCOUNT_H__ + +#include <stddef.h> + +#define REFCOUNT_MEMBER_NAME DO_NOT_TOUCH_THIS_MEMBER_refcount + +/* + * Include this member in your structure in order to be able to use it with + * the refcount_* functions. + */ +#define REFCOUNT_COMMON int REFCOUNT_MEMBER_NAME + +/* + * Allocate a new structure that uses reference counting. The resulting pointer + * returned. You must not free the returned pointer manually. It will be freed + * when 'ctx' is freed with talloc_free() and no other references are left. + */ +#define rc_alloc(ctx, type) \ + (type *)_rc_alloc(ctx, sizeof(type), offsetof(type, REFCOUNT_MEMBER_NAME), \ + #type) + +/* + * Increment the reference count of 'src' and return it back if we are + * successful. The reference count will be decremented after 'ctx' has been + * released by talloc_free(). The function will return NULL in case of failure. + */ +#define rc_reference(ctx, type, src) \ + (type *)_rc_reference(ctx, offsetof(type, REFCOUNT_MEMBER_NAME), src) + +/* + * These functions should not be used directly. Use the above macros instead. + */ +void *_rc_alloc(const void *context, size_t size, size_t refcount_offset, + const char *type_name); +void *_rc_reference(const void *context, size_t refcount_offset, void *source); + + +#endif /* !__REFCOUNT_H__ */ |