From 7b79694eadc288592729567c3caa7c70f6662760 Mon Sep 17 00:00:00 2001 From: Andrew Tridgell Date: Sun, 16 Jan 2005 23:21:52 +0000 Subject: r4790: added type checking helper macros in talloc. These take advantage of the type names that talloc already keeps around for pointers, and allows the user to type check void* private pointers. It can also be used to implement polymorphism in C, as I'm sure someone would have pointed out to me sooner or later :-) (This used to be commit c283e1a3efac3a92e29a35856e20eb61ef4c221e) --- source4/lib/talloc/talloc.c | 19 ++++++++++++++ source4/lib/talloc/talloc.h | 14 ++++++---- source4/lib/talloc/talloc_guide.txt | 32 +++++++++++++++++++++++ source4/lib/talloc/testsuite.c | 51 ++++++++++++++++++++++++++++++++++--- 4 files changed, 107 insertions(+), 9 deletions(-) (limited to 'source4/lib/talloc') diff --git a/source4/lib/talloc/talloc.c b/source4/lib/talloc/talloc.c index e05b196592..f6f7e899d1 100644 --- a/source4/lib/talloc/talloc.c +++ b/source4/lib/talloc/talloc.c @@ -424,6 +424,23 @@ const char *talloc_get_name(const void *ptr) return "UNNAMED"; } + +/* + check if a pointer has the given name. If it does, return the pointer, + otherwise return NULL +*/ +void *talloc_check_name(const void *ptr, const char *name) +{ + const char *pname; + if (ptr == NULL) return NULL; + pname = talloc_get_name(ptr); + if (pname == name || strcmp(pname, name) == 0) { + return discard_const_p(void, ptr); + } + return NULL; +} + + /* this is for compatibility with older versions of talloc */ @@ -1029,3 +1046,5 @@ void *talloc_autofree_context(void) } return cleanup_context; } + + diff --git a/source4/lib/talloc/talloc.h b/source4/lib/talloc/talloc.h index 607ca4ca47..0a98881054 100644 --- a/source4/lib/talloc/talloc.h +++ b/source4/lib/talloc/talloc.h @@ -37,7 +37,7 @@ typedef void TALLOC_CTX; #endif /* useful macros for creating type checked pointers */ -#define talloc(ctx, type) (type *)talloc_named_const(ctx, sizeof(type), #type ": " __location__) +#define talloc(ctx, type) (type *)talloc_named_const(ctx, sizeof(type), #type) #define talloc_size(ctx, size) talloc_named_const(ctx, size, __location__) #define talloc_new(ctx) talloc_named_const(ctx, 0, "talloc_new: " __location__) @@ -45,11 +45,11 @@ typedef void TALLOC_CTX; #define talloc_zero(ctx, type) (type *)_talloc_zero(ctx, sizeof(type), #type) #define talloc_zero_size(ctx, size) _talloc_zero(ctx, size, __location__) -#define talloc_zero_array(ctx, type, count) (type *)_talloc_zero_array(ctx, sizeof(type), count, __location__) -#define talloc_array(ctx, type, count) (type *)_talloc_array(ctx, sizeof(type), count, __location__) +#define talloc_zero_array(ctx, type, count) (type *)_talloc_zero_array(ctx, sizeof(type), count, #type) +#define talloc_array(ctx, type, count) (type *)_talloc_array(ctx, sizeof(type), count, #type) #define talloc_array_size(ctx, size, count) _talloc_array(ctx, size, count, __location__) -#define talloc_realloc(ctx, p, type, count) (type *)_talloc_realloc_array(ctx, p, sizeof(type), count, __location__) +#define talloc_realloc(ctx, p, type, count) (type *)_talloc_realloc_array(ctx, p, sizeof(type), count, #type) #define talloc_realloc_size(ctx, ptr, size) _talloc_realloc(ctx, ptr, size, __location__) #define talloc_memdup(t, p, size) _talloc_memdup(t, p, size, __location__) @@ -62,6 +62,9 @@ typedef void TALLOC_CTX; #define data_blob_talloc(ctx, ptr, size) data_blob_talloc_named(ctx, ptr, size, "DATA_BLOB: "__location__) #define data_blob_dup_talloc(ctx, blob) data_blob_talloc_named(ctx, (blob)->data, (blob)->length, "DATA_BLOB: "__location__) +#define talloc_set_type(ptr, type) talloc_set_name_const(ptr, #type) +#define talloc_get_type(ptr, type) (type *)talloc_check_name(ptr, #type) + #if TALLOC_DEPRECATED #define talloc_zero_p(ctx, type) talloc_zero(ctx, type) @@ -76,7 +79,7 @@ typedef void TALLOC_CTX; #endif -/* The following definitions come from lib/talloc.c */ +/* The following definitions come from talloc.c */ void *_talloc(const void *context, size_t size); void talloc_set_destructor(const void *ptr, int (*destructor)(void *)); void talloc_increase_ref_count(const void *ptr); @@ -88,6 +91,7 @@ void *talloc_named(const void *context, size_t size, const char *fmt, ...) PRINTF_ATTRIBUTE(3,4); void *talloc_named_const(const void *context, size_t size, const char *name); const char *talloc_get_name(const void *ptr); +void *talloc_check_name(const void *ptr, const char *name); void talloc_report_depth(const void *ptr, FILE *f, int depth); void *talloc_parent(const void *ptr); void *talloc_init(const char *fmt, ...) PRINTF_ATTRIBUTE(1,2); diff --git a/source4/lib/talloc/talloc_guide.txt b/source4/lib/talloc/talloc_guide.txt index 30b7f64d67..927bd366fd 100644 --- a/source4/lib/talloc/talloc_guide.txt +++ b/source4/lib/talloc/talloc_guide.txt @@ -512,3 +512,35 @@ void *talloc_autofree_context(void); This is a handy utility function that returns a talloc context which will be automatically freed on program exit. This can be used to reduce the noise in memory leak reports. + + +=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- +void *talloc_check_name(const void *ptr, const char *name); + +This function checks if a pointer has the specified name. If it does +then the pointer is returned. It it doesn't then NULL is returned. + + +=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- +(type *)talloc_get_type(const void *ptr, type); + +This macro allows you to do type checking on talloc pointers. It is +particularly useful for void* private pointers. It is equivalent to +this: + + (type *)talloc_check_name(ptr, #type) + + +=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- +talloc_set_type(const void *ptr, type); + +This macro allows you to force the name of a pointer to be a +particular type. This can be used in conjunction with +talloc_get_type() to do type checking on void* pointers. + +It is equivalent to this: + talloc_set_name_const(ptr, #type) + + + + diff --git a/source4/lib/talloc/testsuite.c b/source4/lib/talloc/testsuite.c index bc1c18fdc1..4a1074e045 100644 --- a/source4/lib/talloc/testsuite.c +++ b/source4/lib/talloc/testsuite.c @@ -609,6 +609,48 @@ static BOOL test_realloc_child(void) return True; } + +/* + test type checking +*/ +static BOOL test_type(void) +{ + void *root; + struct el1 { + int count; + }; + struct el2 { + int count; + }; + struct el1 *el1; + + printf("TESTING talloc type checking\n"); + + root = talloc_new(NULL); + + el1 = talloc(root, struct el1); + + el1->count = 1; + + if (talloc_get_type(el1, struct el1) != el1) { + printf("type check failed on el1\n"); + return False; + } + if (talloc_get_type(el1, struct el2) != NULL) { + printf("type check failed on el1 with el2\n"); + return False; + } + talloc_set_type(el1, struct el2); + if (talloc_get_type(el1, struct el2) != el1) { + printf("type set failed on el1 with el2\n"); + return False; + } + + talloc_free(root); + + return True; +} + /* test steal */ @@ -664,13 +706,13 @@ static BOOL test_steal(void) } /* - test ldb alloc fn + test talloc_realloc_fn */ -static BOOL test_ldb(void) +static BOOL test_realloc_fn(void) { void *root, *p1; - printf("TESTING LDB\n"); + printf("TESTING talloc_realloc_fn\n"); root = talloc_new(NULL); @@ -774,7 +816,8 @@ BOOL torture_local_talloc(void) ret &= test_realloc_child(); ret &= test_steal(); ret &= test_unref_reparent(); - ret &= test_ldb(); + ret &= test_realloc_fn(); + ret &= test_type(); if (ret) { ret &= test_speed(); } -- cgit