typesafe_cb: simplify, preserve namespace.

Get rid of many variants, which were just confusing for most people.
Keep typesafe_cb(), typesafe_cb_preargs() and typesafe_cb_postarts(),
and rework cast_if_type() into typesafe_cb_cast() so we stay in our
namespace.

I should have done this as soon as I discovered the limitation that
the types have to be defined if I want const-taking callbacks.

ccan/antithread/antithread.h

@@ -16,7 +16,7 @@ const void *at_pool_ctx(struct at_pool *atp);
 /* Creating an antithread via fork().  Returned athread is child of pool. */
 #define at_run(pool, fn, arg)						\
 	_at_run(pool,							\
-		typesafe_cb_preargs(void *, (fn), (arg), struct at_pool *), \
+		typesafe_cb_preargs(void *, void *, (fn), (arg), struct at_pool *), \
 		(arg))
 
 /* Fork and execvp, with added arguments for child to grab.

ccan/asearch/asearch.h

@@ -23,10 +23,11 @@
 #if HAVE_TYPEOF
 #define asearch(key, base, num, cmp)					\
 	((__typeof__(*(base))*)(bsearch((key), (base), (num), sizeof(*(base)), \
-		cast_if_type(int (*)(const void *, const void *),	\
-			     (cmp), &*(cmp),				\
-			     int (*)(const __typeof__(*(key)) *,	\
-				     const __typeof__(*(base)) *)))))
+		typesafe_cb_cast(int (*)(const void *, const void *),	\
+				 int (*)(const __typeof__(*(key)) *,	\
+					 const __typeof__(*(base)) *),	\
+				 (cmp)))))
+
 #else
 #define asearch(key, base, num, cmp)				\
 	(bsearch((key), (base), (num), sizeof(*(base)),		\

ccan/asort/asort.h

@@ -19,11 +19,12 @@
  */
 #define asort(base, num, cmp, ctx)					\
 _asort((base), (num), sizeof(*(base)),					\
-       cast_if_type(int (*)(const void *, const void *, void *),	\
-		    (cmp), &*(cmp),					\
-		    int (*)(const __typeof__(*(base)) *,		\
-			    const __typeof__(*(base)) *,		\
-			    __typeof__(ctx))), (ctx))
+       typesafe_cb_cast(int (*)(const void *, const void *, void *),	\
+			int (*)(const __typeof__(*(base)) *,		\
+				const __typeof__(*(base)) *,		\
+				__typeof__(ctx)),			\
+			(cmp)),						\
+       (ctx))
 
 #if HAVE_QSORT_R_PRIVATE_LAST
 #define _asort(b, n, s, cmp, ctx) qsort_r(b, n, s, cmp, ctx)

ccan/opt/opt.h

@@ -315,22 +315,22 @@ struct opt_table {
 /* Resolves to the four parameters for non-arg callbacks. */
 #define OPT_CB_NOARG(cb, arg)				\
 	OPT_NOARG,					\
-	cast_if_any(char *(*)(void *), (cb), 0?(cb):(cb),\
-		    char *(*)(typeof(*(arg))*),		\
-		    char *(*)(const typeof(*(arg))*),	\
-		    char *(*)(const void *)),		\
+	typesafe_cb_cast3(char *(*)(void *),	\
+			  char *(*)(typeof(*(arg))*),	\
+			  char *(*)(const typeof(*(arg))*),	\
+			  char *(*)(const void *), (cb)),	\
 	NULL, NULL
 
 /* Resolves to the four parameters for arg callbacks. */
 #define OPT_CB_ARG(cb, show, arg)					\
 	OPT_HASARG, NULL,						\
-	cast_if_any(char *(*)(const char *,void *), (cb), 0?(cb):(cb),	\
-		    char *(*)(const char *, typeof(*(arg))*),		\
-		    char *(*)(const char *, const typeof(*(arg))*),	\
-		    char *(*)(const char *, const void *)),		\
-	cast_if_type(void (*)(char buf[], const void *), (show),	\
-		     0?(show):(show),					\
-		     void (*)(char buf[], const typeof(*(arg))*))
+	typesafe_cb_cast3(char *(*)(const char *,void *),	\
+			  char *(*)(const char *, typeof(*(arg))*),	\
+			  char *(*)(const char *, const typeof(*(arg))*), \
+			  char *(*)(const char *, const void *),	\
+			  (cb)),					\
+	typesafe_cb_cast(void (*)(char buf[], const void *),		\
+			 void (*)(char buf[], const typeof(*(arg))*), (show))
 
 /* Non-typesafe register function. */
 void _opt_register(const char *names, enum opt_type type,

ccan/sparse_bsearch/_info

@@ -15,7 +15,7 @@
  * Example:
  *	#include <ccan/sparse_bsearch/sparse_bsearch.h>
  *
- *	static bool val_valid(unsigned int *val)
+ *	static bool val_valid(const unsigned int *val)
  *	{
  *		return *val != 0;
  *	}

ccan/sparse_bsearch/sparse_bsearch.h

@@ -14,9 +14,10 @@
  * @validfn: whether this element is valid.
  *
  * Binary search of a sorted array, which may have some invalid entries.
+ * Note that cmpfn and validfn take const pointers.
  *
  * Example:
- *	static bool val_valid(unsigned int *val)
+ *	static bool val_valid(const unsigned int *val)
  *	{
  *		return *val != 0;
  *	}
@@ -40,8 +41,13 @@
 #define sparse_bsearch(key, base, nmemb, cmpfn, validfn)		\
 	_sparse_bsearch((key)+check_types_match((key), &(base)[0]),	\
 			(base), (nmemb), sizeof((base)[0]),		\
-			typesafe_cb_cmp(int, (cmpfn), (base)),		\
-			typesafe_cb_const(bool, (validfn), (base)))
+			typesafe_cb_cast(int (*)(const void *, const void *), \
+					 int (*)(const __typeof__(*(base)) *, \
+						 const __typeof__(*(base)) *), \
+					 (cmpfn)),			\
+			typesafe_cb_cast(bool (*)(const void *),	\
+					 bool (*)(const __typeof__(*(base)) *), \
+					 (validfn)))
 
 void *_sparse_bsearch(const void *key, const void *base,
 		      size_t nmemb, size_t size,

ccan/talloc/talloc.h

@@ -210,7 +210,7 @@ int talloc_free(const void *ptr);
  *	talloc, talloc_free
  */
 #define talloc_set_destructor(ptr, function)				      \
-	_talloc_set_destructor((ptr), typesafe_cb_def(int, (function), (ptr)))
+	_talloc_set_destructor((ptr), typesafe_cb(int, void *, (function), (ptr)))
 
 /**
  * talloc_zero - allocate zeroed dynamic memory for a type

ccan/tdb2/tdb2.h

@@ -311,7 +311,7 @@ enum TDB_ERROR tdb_transaction_prepare_commit(struct tdb_context *tdb);
  * a negative enum TDB_ERROR value.
  */
 #define tdb_traverse(tdb, fn, p)					\
-	tdb_traverse_(tdb, typesafe_cb_preargs(int, (fn), (p),		\
+	tdb_traverse_(tdb, typesafe_cb_preargs(int, void *, (fn), (p),	\
 					       struct tdb_context *,	\
 					       TDB_DATA, TDB_DATA), (p))
 
@@ -334,7 +334,8 @@ int64_t tdb_traverse_(struct tdb_context *tdb,
  */
 #define tdb_parse_record(tdb, key, parse, p)				\
 	tdb_parse_record_((tdb), (key),					\
-			  typesafe_cb_preargs(enum TDB_ERROR, (parse), (p), \
+			  typesafe_cb_preargs(enum TDB_ERROR, void *,	\
+					      (parse), (p),		\
 					      TDB_DATA, TDB_DATA), (p))
 
 enum TDB_ERROR tdb_parse_record_(struct tdb_context *tdb,
@@ -472,7 +473,7 @@ enum TDB_ERROR tdb_wipe_all(struct tdb_context *tdb);
  * Returns TDB_SUCCESS or an error.
  */
 #define tdb_check(tdb, check, private_data)				\
-	tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR,		\
+	tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR, void *,	\
 					      (check), (private_data),	\
 					      struct tdb_data,		\
 					      struct tdb_data),		\

ccan/typesafe_cb/_info

@@ -5,7 +5,7 @@
 /**
  * typesafe_cb - macros for safe callbacks.
  *
- * The basis of the typesafe_cb header is cast_if_type(): a
+ * The basis of the typesafe_cb header is typesafe_cb_cast(): a
  * conditional cast macro.   If an expression exactly matches a given
  * type, it is cast to the target type, otherwise it is left alone.
  *
@@ -35,15 +35,16 @@
  * the exactly correct function type to match the argument, or a
  * function which takes a void *.
  *
- * This is where typesafe_cb() comes in: it uses cast_if_type() to
+ * This is where typesafe_cb() comes in: it uses typesafe_cb_cast() to
  * cast the callback function if it matches the argument type:
  *
  *	void _register_callback(void (*cb)(void *arg), void *arg);
  *	#define register_callback(cb, arg)				\
- *		_register_callback(typesafe_cb(void, (cb), (arg)), (arg))
+ *		_register_callback(typesafe_cb(void, void *, (cb), (arg)), \
+ *				   (arg))
  *
  * On compilers which don't support the extensions required
- * cast_if_type() and friend become an unconditional cast, so your
+ * typesafe_cb_cast() and friend become an unconditional cast, so your
  * code will compile but you won't get type checking.
  *
  * Example:
@@ -72,7 +73,8 @@
  *	}
  *	#define register_callback(value, cb, arg)			\
  *		_register_callback(value,				\
- *				   typesafe_cb_preargs(int, (cb), (arg), int),\
+ *				   typesafe_cb_preargs(int, void *,	\
+ *						       (cb), (arg), int),\
  *				   (arg))
  *	
  *	static struct callback *find_callback(int value)

ccan/typesafe_cb/test/compile_fail-cast_if_type-promotable.c

@@ -6,14 +6,14 @@ static void _set_some_value(void *val)
 }
 
 #define set_some_value(expr)						\
-	_set_some_value(cast_if_type(void *, (expr), (expr), long))
+	_set_some_value(typesafe_cb_cast(void *, long, (expr)))
 
 int main(int argc, char *argv[])
 {
 #ifdef FAIL
 	bool x = 0;
 #if !HAVE_TYPEOF||!HAVE_BUILTIN_CHOOSE_EXPR||!HAVE_BUILTIN_TYPES_COMPATIBLE_P
-#error "Unfortunately we don't fail if cast_if_type is a noop."
+#error "Unfortunately we don't fail if typesafe_cb_cast is a noop."
 #endif
 #else
 	long x = 0;

ccan/typesafe_cb/test/compile_fail-typesafe_cb.c

@@ -6,7 +6,7 @@ static void _register_callback(void (*cb)(void *arg), void *arg)
 }
 
 #define register_callback(cb, arg)				\
-	_register_callback(typesafe_cb(void, (cb), (arg)), (arg))
+	_register_callback(typesafe_cb(void, void *, (cb), (arg)), (arg))
 
 static void my_callback(char *p)
 {
@@ -18,7 +18,7 @@ int main(int argc, char *argv[])
 #ifdef FAIL
 	int *p;
 #if !HAVE_TYPEOF||!HAVE_BUILTIN_CHOOSE_EXPR||!HAVE_BUILTIN_TYPES_COMPATIBLE_P
-#error "Unfortunately we don't fail if cast_if_type is a noop."
+#error "Unfortunately we don't fail if typesafe_cb_cast is a noop."
 #endif
 #else
 	char *p;

ccan/typesafe_cb/test/compile_fail-cast_if_any.c → ccan/typesafe_cb/test/compile_fail-typesafe_cb_cast-multi.c

@@ -29,14 +29,15 @@ int main(int argc, char *argv[])
 {
 #ifdef FAIL
 	struct other
-#if !HAVE_TYPEOF||!HAVE_BUILTIN_CHOOSE_EXPR||!HAVE_BUILTIN_TYPES_COMPATIBLE_P
-#error "Unfortunately we don't fail if cast_if_type is a noop."
+#if !HAVE_TYPEOF || !HAVE_CAST_TO_UNION
+#error "Unfortunately we don't fail if typesafe_cb_cast is a noop."
 #endif
 #else
 	struct foo
 #endif
 		*arg = NULL;
-	take_any(cast_if_any(struct any *, arg, arg,
-			     struct foo *, struct bar *, struct baz *));
+	take_any(typesafe_cb_cast3(struct any *,
+				   struct foo *, struct bar *, struct baz *,
+				   arg));
 	return 0;
 }

ccan/typesafe_cb/test/compile_fail-cast_if_type.c → ccan/typesafe_cb/test/compile_fail-typesafe_cb_cast.c

@@ -7,15 +7,15 @@ void _set_some_value(void *val)
 }
 
 #define set_some_value(expr)						\
-	_set_some_value(cast_if_type(void *, (expr), (expr), unsigned long))
+	_set_some_value(typesafe_cb_cast(void *, unsigned long, (expr)))
 
 int main(int argc, char *argv[])
 {
 #ifdef FAIL
 	int x = 0;
 	set_some_value(x);
-#if !HAVE_TYPEOF||!HAVE_BUILTIN_CHOOSE_EXPR||!HAVE_BUILTIN_TYPES_COMPATIBLE_P
-#error "Unfortunately we don't fail if cast_if_type is a noop."
+#if !HAVE_TYPEOF||!HAVE_CAST_TO_UNION
+#error "Unfortunately we don't fail if typesafe_cb_cast is a noop."
 #endif
 #else
 	void *p = 0;

ccan/typesafe_cb/test/compile_fail-typesafe_cb_exact.c

-#include <ccan/typesafe_cb/typesafe_cb.h>
-#include <stdlib.h>
-
-static void _register_callback(void (*cb)(void *arg), const void *arg)
-{
-}
-
-#define register_callback(cb, arg)				\
-	_register_callback(typesafe_cb_exact(void, (cb), (arg)), (arg))
-
-static void my_callback(const char *p)
-{
-}
-
-int main(int argc, char *argv[])
-{
-#ifdef FAIL
-	char *p;
-#if !HAVE_TYPEOF||!HAVE_BUILTIN_CHOOSE_EXPR||!HAVE_BUILTIN_TYPES_COMPATIBLE_P
-#error "Unfortunately we don't fail if cast_if_type is a noop."
-#endif
-#else
-	const char *p;
-#endif
-	p = NULL;
-
-	/* This should work always. */
-	register_callback(my_callback, (const char *)"hello world");
-
-	/* This will fail with FAIL defined */
-	register_callback(my_callback, p);
-	return 0;
-}

ccan/typesafe_cb/test/compile_fail-typesafe_cb_postargs.c

@@ -5,7 +5,7 @@ static void _register_callback(void (*cb)(void *arg, int x), void *arg)
 {
 }
 #define register_callback(cb, arg)				\
-	_register_callback(typesafe_cb_postargs(void, (cb), (arg), int), (arg))
+	_register_callback(typesafe_cb_postargs(void, void *, (cb), (arg), int), (arg))
 
 static void my_callback(char *p, int x)
 {
@@ -16,7 +16,7 @@ int main(int argc, char *argv[])
 #ifdef FAIL
 	int *p;
 #if !HAVE_TYPEOF||!HAVE_BUILTIN_CHOOSE_EXPR||!HAVE_BUILTIN_TYPES_COMPATIBLE_P
-#error "Unfortunately we don't fail if cast_if_type is a noop."
+#error "Unfortunately we don't fail if typesafe_cb_cast is a noop."
 #endif
 #else
 	char *p;

ccan/typesafe_cb/test/compile_fail-typesafe_cb_preargs.c

@@ -6,7 +6,7 @@ static void _register_callback(void (*cb)(int x, void *arg), void *arg)
 }
 
 #define register_callback(cb, arg)				\
-	_register_callback(typesafe_cb_preargs(void, (cb), (arg), int), (arg))
+	_register_callback(typesafe_cb_preargs(void, void *, (cb), (arg), int), (arg))
 
 static void my_callback(int x, char *p)
 {
@@ -17,7 +17,7 @@ int main(int argc, char *argv[])
 #ifdef FAIL
 	int *p;
 #if !HAVE_TYPEOF||!HAVE_BUILTIN_CHOOSE_EXPR||!HAVE_BUILTIN_TYPES_COMPATIBLE_P
-#error "Unfortunately we don't fail if cast_if_type is a noop."
+#error "Unfortunately we don't fail if typesafe_cb_cast is a noop."
 #endif
 #else
 	char *p;

ccan/typesafe_cb/test/compile_ok-typesafe_cb-NULL.c

 #include <ccan/typesafe_cb/typesafe_cb.h>
 #include <stdlib.h>
 
-/* NULL args for callback function should be OK for _exact and _def. */
+/* NULL args for callback function should be OK for normal and _def. */
 
 static void _register_callback(void (*cb)(const void *arg), const void *arg)
 {
 }
 
-#define register_callback_def(cb, arg)				\
-	_register_callback(typesafe_cb_def(void, (cb), (arg)), (arg))
-
-#define register_callback_exact(cb, arg)				\
-	_register_callback(typesafe_cb_exact(void, (cb), (arg)), (arg))
+#define register_callback(cb, arg)				\
+	_register_callback(typesafe_cb(void, const void *, (cb), (arg)), (arg))
 
 int main(int argc, char *argv[])
 {
-	register_callback_def(NULL, "hello world");
-	register_callback_exact(NULL, "hello world");
+	register_callback(NULL, "hello world");
 	return 0;
 }

ccan/typesafe_cb/test/compile_ok-typesafe_cb-const.c

-#include <ccan/typesafe_cb/typesafe_cb.h>
-#include <stdlib.h>
-
-/* const args in callbacks should be OK. */
-
-static void _register_callback(void (*cb)(void *arg), void *arg)
-{
-}
-
-#define register_callback(cb, arg)				\
-	_register_callback(typesafe_cb(void, (cb), (arg)), (arg))
-
-#define register_callback_def(cb, arg)				\
-	_register_callback(typesafe_cb_def(void, (cb), (arg)), (arg))
-
-static void _register_callback_pre(void (*cb)(int x, void *arg), void *arg)
-{
-}
-
-#define register_callback_pre(cb, arg)					\
-	_register_callback_pre(typesafe_cb_preargs(void, (cb), (arg), int), (arg))
-
-static void _register_callback_post(void (*cb)(void *arg, int x), void *arg)
-{
-}
-
-#define register_callback_post(cb, arg)					\
-	_register_callback_post(typesafe_cb_postargs(void, (cb), (arg), int), (arg))
-
-static void my_callback(const char *p)
-{
-}
-
-static void my_callback_pre(int x, /*const*/ char *p)
-{
-}
-
-static void my_callback_post(/*const*/ char *p, int x)
-{
-}
-
-int main(int argc, char *argv[])
-{
-	char p[] = "hello world";
-	register_callback(my_callback, p);
-	register_callback_def(my_callback, p);
-	register_callback_pre(my_callback_pre, p);
-	register_callback_post(my_callback_post, p);
-	return 0;
-}

ccan/typesafe_cb/test/compile_ok-typesafe_cb-undefined.c

@@ -8,25 +8,25 @@ static void _register_callback(void (*cb)(void *arg), void *arg)
 }
 
 #define register_callback(cb, arg)				\
-	_register_callback(typesafe_cb(void, (cb), (arg)), (arg))
+	_register_callback(typesafe_cb(void, void *, (cb), (arg)), (arg))
 
 static void _register_callback_pre(void (*cb)(int x, void *arg), void *arg)
 {
 }
 
 #define register_callback_pre(cb, arg)					\
-	_register_callback_pre(typesafe_cb_preargs(void, (cb), (arg), int), (arg))
+	_register_callback_pre(typesafe_cb_preargs(void, void *, (cb), (arg), int), (arg))
 
 static void _register_callback_post(void (*cb)(void *arg, int x), void *arg)
 {
 }
 
 #define register_callback_post(cb, arg)					\
-	_register_callback_post(typesafe_cb_postargs(void, (cb), (arg), int), (arg))
+	_register_callback_post(typesafe_cb_postargs(void, void *, (cb), (arg), int), (arg))
 
 struct undefined;
 
-static void my_callback(const struct undefined *undef)
+static void my_callback(struct undefined *undef)
 {
 }
 

ccan/typesafe_cb/test/compile_ok-typesafe_cb-vars.c

@@ -8,25 +8,25 @@ static void _register_callback(void (*cb)(void *arg), void *arg)
 }
 
 #define register_callback(cb, arg)				\
-	_register_callback(typesafe_cb(void, (cb), (arg)), (arg))
+	_register_callback(typesafe_cb(void, void *, (cb), (arg)), (arg))
 
 static void _register_callback_pre(void (*cb)(int x, void *arg), void *arg)
 {
 }
 
 #define register_callback_pre(cb, arg)					\
-	_register_callback_pre(typesafe_cb_preargs(void, (cb), (arg), int), (arg))
+	_register_callback_pre(typesafe_cb_preargs(void, void *, (cb), (arg), int), (arg))
 
 static void _register_callback_post(void (*cb)(void *arg, int x), void *arg)
 {
 }
 
 #define register_callback_post(cb, arg)					\
-	_register_callback_post(typesafe_cb_postargs(void, (cb), (arg), int), (arg))
+	_register_callback_post(typesafe_cb_postargs(void, void *, (cb), (arg), int), (arg))
 
 struct undefined;
 
-static void my_callback(const struct undefined *undef)
+static void my_callback(struct undefined *undef)
 {
 }
 
@@ -41,7 +41,7 @@ static void my_callback_post(struct undefined *undef, int x)
 int main(int argc, char *argv[])
 {
 	struct undefined *handle = NULL;
-	void (*cb)(const struct undefined *undef) = my_callback;
+	void (*cb)(struct undefined *undef) = my_callback;
 	void (*pre)(int x, struct undefined *undef) = my_callback_pre;
 	void (*post)(struct undefined *undef, int x) = my_callback_post;
 

ccan/typesafe_cb/test/compile_ok-typesafe_cb-volatile.c

-#include <ccan/typesafe_cb/typesafe_cb.h>
-#include <stdlib.h>
-
-/* volatile args in callbacks should be OK. */
-
-static void _register_callback(void (*cb)(void *arg), void *arg)
-{
-}
-
-#define register_callback(cb, arg)				\
-	_register_callback(typesafe_cb(void, (cb), (arg)), (arg))
-
-static void _register_callback_pre(void (*cb)(int x, void *arg), void *arg)
-{
-}
-
-#define register_callback_pre(cb, arg)					\
-	_register_callback_pre(typesafe_cb_preargs(void, (cb), (arg), int), (arg))
-
-static void _register_callback_post(void (*cb)(void *arg, int x), void *arg)
-{
-}
-
-#define register_callback_post(cb, arg)					\
-	_register_callback_post(typesafe_cb_postargs(void, (cb), (arg), int), (arg))
-
-static void my_callback(volatile char *p)
-{
-}
-
-/* FIXME: Can't handle volatile for these */
-static void my_callback_pre(int x, /* volatile */ char *p)
-{
-}
-
-static void my_callback_post(/* volatile */ char *p, int x)
-{
-}
-
-int main(int argc, char *argv[])
-{
-	char p[] = "hello world";
-	register_callback(my_callback, p);
-	register_callback_pre(my_callback_pre, p);
-	register_callback_post(my_callback_post, p);
-	return 0;
-}

ccan/typesafe_cb/test/compile_ok-cast_if_any.c → ccan/typesafe_cb/test/compile_ok-typesafe_cb_cast.c

@@ -23,19 +23,19 @@ static void take_any(struct any *any)
 
 int main(int argc, char *argv[])
 {
-#if HAVE_TYPEOF
 	/* Otherwise we get unused warnings for these. */
 	struct foo *foo = NULL;
 	struct bar *bar = NULL;
 	struct baz *baz = NULL;
-#endif
-	struct other *arg = NULL;
 
-	take_any(cast_if_any(struct any *, arg, foo,
-			     struct foo *, struct bar *, struct baz *));
-	take_any(cast_if_any(struct any *, arg, bar,
-			     struct foo *, struct bar *, struct baz *));
-	take_any(cast_if_any(struct any *, arg, baz,
-			     struct foo *, struct bar *, struct baz *));
+	take_any(typesafe_cb_cast3(struct any *,
+				   struct foo *, struct bar *, struct baz *,
+				   foo));
+	take_any(typesafe_cb_cast3(struct any *, 
+				   struct foo *, struct bar *, struct baz *,
+				   bar));
+	take_any(typesafe_cb_cast3(struct any *, 
+				   struct foo *, struct bar *, struct baz *,
+				   baz));
 	return 0;
 }

ccan/typesafe_cb/test/compile_ok-typesafe_cb_def-const.c

-#include <ccan/typesafe_cb/typesafe_cb.h>
-#include <stdlib.h>
-
-/* const args in callbacks should be OK. */
-
-static void _register_callback(void (*cb)(void *arg), void *arg)
-{
-}
-
-#define register_callback(cb, arg)				\
-	_register_callback(typesafe_cb(void, (cb), (arg)), (arg))
-
-static void _register_callback_pre(void (*cb)(int x, void *arg), void *arg)
-{
-}
-
-#define register_callback_pre(cb, arg)					\
-	_register_callback_pre(typesafe_cb_preargs(void, (cb), (arg), int), (arg))
-
-static void _register_callback_post(void (*cb)(void *arg, int x), void *arg)
-{
-}
-
-#define register_callback_post(cb, arg)					\
-	_register_callback_post(typesafe_cb_postargs(void, (cb), (arg), int), (arg))
-
-static void my_callback(const char *p)
-{
-}
-
-static void my_callback_pre(int x, /*const*/ char *p)
-{
-}
-
-static void my_callback_post(/*const*/ char *p, int x)
-{
-}
-
-int main(int argc, char *argv[])
-{
-	char p[] = "hello world";
-	register_callback(my_callback, p);
-	register_callback_pre(my_callback_pre, p);
-	register_callback_post(my_callback_post, p);
-	return 0;
-}

ccan/typesafe_cb/test/run.c

@@ -12,7 +12,7 @@ static void _set_some_value(void *val)
 }
 
 #define set_some_value(expr)						\
-	_set_some_value(cast_if_type(void *, (expr), (expr), unsigned long))
+	_set_some_value(typesafe_cb_cast(void *, unsigned long, (expr)))
 
 static void _callback_onearg(void (*fn)(void *arg), void *arg)
 {
@@ -30,30 +30,19 @@ static void _callback_postargs(void (*fn)(void *arg, int a, int b), void *arg)
 }
 
 #define callback_onearg(cb, arg)					\
-	_callback_onearg(typesafe_cb(void, (cb), (arg)), (arg))
+	_callback_onearg(typesafe_cb(void, void *, (cb), (arg)), (arg))
 
 #define callback_preargs(cb, arg)					\
-	_callback_preargs(typesafe_cb_preargs(void, (cb), (arg), int, int), (arg))
+	_callback_preargs(typesafe_cb_preargs(void, void *, (cb), (arg), int, int), (arg))
 
 #define callback_postargs(cb, arg)					\
-	_callback_postargs(typesafe_cb_postargs(void, (cb), (arg), int, int), (arg))
+	_callback_postargs(typesafe_cb_postargs(void, void *, (cb), (arg), int, int), (arg))
 
 static void my_callback_onearg(char *p)
 {
 	ok1(strcmp(p, "hello world") == 0);
 }
 
-static void my_callback_onearg_const(const char *p)
-{
-	ok1(strcmp(p, "hello world") == 0);
-}
-
-static void my_callback_onearg_volatile(volatile char *p)
-{
-	/* Double cast avoids warning on gcc's -Wcast-qual */
-	ok1(strcmp((char *)(intptr_t)p, "hello world") == 0);
-}
-
 static void my_callback_preargs(int a, int b, char *p)
 {
 	ok1(a == 1);
@@ -61,22 +50,6 @@ static void my_callback_preargs(int a, int b, char *p)
 	ok1(strcmp(p, "hello world") == 0);
 }
 
-#if 0 /* FIXME */
-static void my_callback_preargs_const(int a, int b, const char *p)
-{
-	ok1(a == 1);
-	ok1(b == 2);
-	ok1(strcmp(p, "hello world") == 0);
-}
-
-static void my_callback_preargs_volatile(int a, int b, volatile char *p)
-{
-	ok1(a == 1);
-	ok1(b == 2);
-	ok1(strcmp((char *)p, "hello world") == 0);
-}
-#endif
-
 static void my_callback_postargs(char *p, int a, int b)
 {
 	ok1(a == 1);
@@ -84,23 +57,7 @@ static void my_callback_postargs(char *p, int a, int b)
 	ok1(strcmp(p, "hello world") == 0);
 }
 
-#if 0 /* FIXME */
-static void my_callback_postargs_const(const char *p, int a, int b)
-{
-	ok1(a == 1);
-	ok1(b == 2);
-	ok1(strcmp(p, "hello world") == 0);
-}
-
-static void my_callback_postargs_volatile(volatile char *p, int a, int b)
-{
-	ok1(a == 1);
-	ok1(b == 2);
-	ok1(strcmp((char *)p, "hello world") == 0);
-}
-#endif
-
-/* This is simply a compile test; we promised cast_if_type can be in a
+/* This is simply a compile test; we promised typesafe_cb_cast can be in a
  * static initializer. */
 struct callback_onearg
 {
@@ -109,7 +66,7 @@ struct callback_onearg
 };
 
 struct callback_onearg cb_onearg
-= { typesafe_cb(void, my_callback_onearg, (char *)(intptr_t)"hello world"),
+= { typesafe_cb(void, void *, my_callback_onearg, (char *)(intptr_t)"hello world"),
     "hello world" };
 
 struct callback_preargs
@@ -119,7 +76,7 @@ struct callback_preargs
 };
 
 struct callback_preargs cb_preargs
-= { typesafe_cb_preargs(void, my_callback_preargs,
+= { typesafe_cb_preargs(void, void *, my_callback_preargs,
 			(char *)(intptr_t)"hi", int, int), "hi" };
 
 struct callback_postargs
@@ -129,7 +86,7 @@ struct callback_postargs
 };
 
 struct callback_postargs cb_postargs
-= { typesafe_cb_postargs(void, my_callback_postargs, 
+= { typesafe_cb_postargs(void, void *, my_callback_postargs, 
 			 (char *)(intptr_t)"hi", int, int), "hi" };
 
 int main(int argc, char *argv[])
@@ -138,25 +95,15 @@ int main(int argc, char *argv[])
 	unsigned long l = (unsigned long)p;
 	char str[] = "hello world";
 
-	plan_tests(2 + 3 + 3 + 3);
+	plan_tests(2 + 1 + 3 + 3);
 	set_some_value(p);
 	set_some_value(l);
 
 	callback_onearg(my_callback_onearg, str);
-	callback_onearg(my_callback_onearg_const, str);
-	callback_onearg(my_callback_onearg_volatile, str);
 
 	callback_preargs(my_callback_preargs, str);
-#if 0 /* FIXME */
-	callback_preargs(my_callback_preargs_const, str);
-	callback_preargs(my_callback_preargs_volatile, str);
-#endif
 
 	callback_postargs(my_callback_postargs, str);
-#if 0 /* FIXME */
-	callback_postargs(my_callback_postargs_const, str);
-	callback_postargs(my_callback_postargs_volatile, str);
-#endif
 
 	return exit_status();
 }

ccan/typesafe_cb/typesafe_cb.h

-#ifndef CCAN_CAST_IF_TYPE_H
-#define CCAN_CAST_IF_TYPE_H
+#ifndef CCAN_TYPESAFE_CB_H
+#define CCAN_TYPESAFE_CB_H
 #include "config.h"
 
 #if HAVE_TYPEOF && HAVE_BUILTIN_CHOOSE_EXPR && HAVE_BUILTIN_TYPES_COMPATIBLE_P
 /**
- * cast_if_type - only cast an expression if test matches a given type
+ * typesafe_cb_cast - only cast an expression if it matches a given type
  * @desttype: the type to cast to
- * @expr: the expression to cast
- * @test: the expression to test
  * @oktype: the type we allow
+ * @expr: the expression to cast
  *
  * This macro is used to create functions which allow multiple types.
  * The result of this macro is used somewhere that a @desttype type is
- * expected: if @test is exactly of type @oktype, then @expr will be
+ * expected: if @expr is exactly of type @oktype, then it will be
  * cast to @desttype type, otherwise left alone.
  *
  * This macro can be used in static initializers.
  *
  * This is merely useful for warnings: if the compiler does not
- * support the primitives required for cast_if_type(), it becomes an
- * unconditional cast, and the @test and @oktype argument is not used.  In
- * particular, this means that @oktype can be a type which uses
- * the "typeof": it will not be evaluated if typeof is not supported.
+ * support the primitives required for typesafe_cb_cast(), it becomes an
+ * unconditional cast, and the @oktype argument is not used.  In
+ * particular, this means that @oktype can be a type which uses the
+ * "typeof": it will not be evaluated if typeof is not supported.
  *
  * Example:
  *	// We can take either an unsigned long or a void *.
  *	void _set_some_value(void *val);
  *	#define set_some_value(e)			\
- *		_set_some_value(cast_if_type(void *, (e), (e), unsigned long))
+ *		_set_some_value(typesafe_cb_cast(void *, (e), unsigned long))
  */
-#define cast_if_type(desttype, expr, test, oktype)			\
-	__builtin_choose_expr(__builtin_types_compatible_p(typeof(test), oktype), \
-			(desttype)(expr), (expr))
+#define typesafe_cb_cast(desttype, oktype, expr)			\
+	__builtin_choose_expr(						\
+		__builtin_types_compatible_p(__typeof__(0?(expr):(expr)), \
+					     oktype),			\
+		(desttype)(expr), (expr))
 #else
-#define cast_if_type(desttype, expr, test, oktype) ((desttype)(expr))
+#define typesafe_cb_cast(desttype, oktype, expr) ((desttype)(expr))
 #endif
 
 /**
- * cast_if_any - only cast an expression if it is one of the three given types
+ * typesafe_cb_cast3 - only cast an expression if it matches given types
  * @desttype: the type to cast to
- * @expr: the expression to cast
- * @test: the expression to test
  * @ok1: the first type we allow
  * @ok2: the second type we allow
  * @ok3: the third type we allow
+ * @expr: the expression to cast
  *
- * This is a convenient wrapper for multiple cast_if_type() calls.  You can
- * chain them inside each other (ie. use cast_if_any() for expr) if you need
- * more than 3 arguments.
+ * This is a convenient wrapper for multiple typesafe_cb_cast() calls.
+ * You can chain them inside each other (ie. use typesafe_cb_cast()
+ * for expr) if you need more than 3 arguments.
  *
  * Example:
  *	// We can take either a long, unsigned long, void * or a const void *.
  *	void _set_some_value(void *val);
  *	#define set_some_value(expr)					\
- *		_set_some_value(cast_if_any(void *, (expr), (expr),	\
- *					    long, unsigned long, const void *))
+ *		_set_some_value(typesafe_cb_cast3(void *,,		\
+ *					    long, unsigned long, const void *,\
+ *					    (expr)))
  */
-#define cast_if_any(desttype, expr, test, ok1, ok2, ok3)		\
-	cast_if_type(desttype,						\
-		     cast_if_type(desttype,				\
-				  cast_if_type(desttype, (expr), (test), ok1), \
-				  (test),				\
-				  ok2),					\
-		     (test),						\
-		     ok3)
+#define typesafe_cb_cast3(desttype, ok1, ok2, ok3, expr)		\
+	typesafe_cb_cast(desttype, ok1,					\
+			 typesafe_cb_cast(desttype, ok2,		\
+					  typesafe_cb_cast(desttype, ok3, \
+							   (expr))))
 
 /**
  * typesafe_cb - cast a callback function if it matches the arg
  * @rtype: the return type of the callback function
+ * @atype: the (pointer) type which the callback function expects.
  * @fn: the callback function to cast
  * @arg: the (pointer) argument to hand to the callback function.
  *
  * If a callback function takes a single argument, this macro does
- * appropriate casts to a function which takes a single void * argument if the
- * callback provided matches the @arg (or a const or volatile version).
- *
- * It is assumed that @arg is of pointer type: usually @arg is passed
- * or assigned to a void * elsewhere anyway.
- *
- * This will not work with a NULL @fn argument: see typesafe_cb_def or
- * typesafe_cb_exact.
- *
- * Example:
- *	void _register_callback(void (*fn)(void *arg), void *arg);
- *	#define register_callback(fn, arg) \
- *		_register_callback(typesafe_cb(void, (fn), (arg)), (arg))
- */
-#define typesafe_cb(rtype, fn, arg)			\
-	cast_if_type(rtype (*)(void *), (fn), (fn)(arg), rtype)
-
-/**
- * typesafe_cb_def - cast a callback fn if it matches arg (of defined type)
- * @rtype: the return type of the callback function
- * @fn: the callback function to cast
- * @arg: the (pointer) argument to hand to the callback function.
- *
- * This is typesafe_cb(), except the type must be defined (eg. if it's
- * struct foo *, the definition of struct foo must be visible).  For many
- * applications, this is reasonable.
- *
- * This variant can accept @fn equal to NULL.
- *
- * Example:
- *	void _register_callback(void (*fn)(void *arg), void *arg);
- *	#define register_callback(fn, arg) \
- *		_register_callback(typesafe_cb_def(void, (fn), (arg)), (arg))
- */
-#define typesafe_cb_def(rtype, fn, arg)				\
-	cast_if_any(rtype (*)(void *), (fn), 0?(fn):(fn),	\
-		    rtype (*)(typeof(*arg)*),			\
-		    rtype (*)(const typeof(*arg)*),		\
-		    rtype (*)(volatile typeof(*arg)*))
-
-/**
- * typesafe_cb_exact - cast a callback fn if it exactly matches arg
- * @rtype: the return type of the callback function
- * @fn: the callback function to cast
- * @arg: the (pointer) argument to hand to the callback function.
- *
- * This is typesafe_cb(), except the @fn can be NULL, or must exactly match
- * the @arg type (no const or volatile).
- *
- * Example:
- *	void _register_callback(void (*fn)(void *arg), void *arg);
- *	#define register_callback(fn, arg) \
- *		_register_callback(typesafe_cb_exact(void, (fn), (arg)), (arg))
- */
-#define typesafe_cb_exact(rtype, fn, arg)				\
-	cast_if_type(rtype (*)(void *), (fn), 0?(fn):(fn),		\
-		     rtype (*)(typeof(arg)))
-
-/**
- * typesafe_cb_const - cast a const callback function if it matches the arg
- * @rtype: the return type of the callback function
- * @fn: the callback function to cast
- * @arg: the (pointer) argument to hand to the callback function.
- *
- * If a callback function takes a single argument, this macro does appropriate
- * casts to a function which takes a single const void * argument if the
+ * appropriate casts to a function which takes a single atype argument if the
  * callback provided matches the @arg.
  *
  * It is assumed that @arg is of pointer type: usually @arg is passed
  * or assigned to a void * elsewhere anyway.
  *
  * Example:
- *	void _register_callback(void (*fn)(const void *arg), const void *arg);
+ *	void _register_callback(void (*fn)(void *arg), void *arg);
  *	#define register_callback(fn, arg) \
- *		_register_callback(typesafe_cb_const(void, (fn), (arg)), (arg))
+ *		_register_callback(typesafe_cb(void, (fn), void*, (arg)), (arg))
  */
-#define typesafe_cb_const(rtype, fn, arg)			\
-	cast_if_type(rtype (*)(const void *), (fn), (fn)(arg), rtype)
+#define typesafe_cb(rtype, atype, fn, arg)			\
+	typesafe_cb_cast(rtype (*)(atype),			\
+			 rtype (*)(__typeof__(arg)),		\
+			 (fn))
 
 /**
  * typesafe_cb_preargs - cast a callback function if it matches the arg
  * @rtype: the return type of the callback function
+ * @atype: the (pointer) type which the callback function expects.
  * @fn: the callback function to cast
  * @arg: the (pointer) argument to hand to the callback function.
  *
@@ -162,17 +99,20 @@
  *
  * Example:
  *	void _register_callback(void (*fn)(int, void *arg), void *arg);
- *	#define register_callback(fn, arg) \
- *		_register_callback(typesafe_cb_preargs(void, (fn), (arg), int),\
+ *	#define register_callback(fn, arg)				   \
+ *		_register_callback(typesafe_cb_preargs(void, (fn), void *, \
+ *				   (arg), int),				   \
  *				   (arg))
  */
-#define typesafe_cb_preargs(rtype, fn, arg, ...)			\
-	cast_if_type(rtype (*)(__VA_ARGS__, void *), (fn), 0?(fn):(fn),	\
-		     rtype (*)(__VA_ARGS__, typeof(arg)))
+#define typesafe_cb_preargs(rtype, atype, fn, arg, ...)			\
+	typesafe_cb_cast(rtype (*)(__VA_ARGS__, atype),			\
+			 rtype (*)(__VA_ARGS__, __typeof__(arg)),	\
+			 (fn))
 
 /**
  * typesafe_cb_postargs - cast a callback function if it matches the arg
  * @rtype: the return type of the callback function
+ * @atype: the (pointer) type which the callback function expects.
  * @fn: the callback function to cast
  * @arg: the (pointer) argument to hand to the callback function.
  *
@@ -182,37 +122,12 @@
  * Example:
  *	void _register_callback(void (*fn)(void *arg, int), void *arg);
  *	#define register_callback(fn, arg) \
- *		_register_callback(typesafe_cb_postargs(void, (fn), (arg), int),\
+ *		_register_callback(typesafe_cb_postargs(void, (fn), void *, \
+ *				   (arg), int),				    \
  *				   (arg))
  */
-#define typesafe_cb_postargs(rtype, fn, arg, ...)			\
-	cast_if_type(rtype (*)(void *, __VA_ARGS__), (fn), 0?(fn):(fn),	\
-		     rtype (*)(typeof(arg), __VA_ARGS__))
-
-/**
- * typesafe_cb_cmp - cast a compare function if it matches the arg
- * @rtype: the return type of the callback function
- * @fn: the callback function to cast
- * @arg: the (pointer) argument(s) to hand to the compare function.
- *
- * If a callback function takes two matching-type arguments, this macro does
- * appropriate casts to a function which takes two const void * arguments if
- * the callback provided takes two a const pointers to @arg.
- *
- * It is assumed that @arg is of pointer type: usually @arg is passed
- * or assigned to a void * elsewhere anyway.  Note also that the type
- * arg points to must be defined.
- *
- * Example:
- *	void _my_qsort(void *base, size_t nmemb, size_t size,
- *		       int (*cmp)(const void *, const void *));
- *	#define my_qsort(base, nmemb, cmpfn) \
- *		_my_qsort((base), (nmemb), sizeof(*(base)), \
- *			  typesafe_cb_cmp(int, (cmpfn), (base)), (arg))
- */
-#define typesafe_cb_cmp(rtype, cmpfn, arg)				\
-	cast_if_type(rtype (*)(const void *, const void *),		\
-		     (cmpfn), 0?(cmpfn):(cmpfn),			\
-		     rtype (*)(const typeof(*arg)*, const typeof(*arg)*))
-		     
+#define typesafe_cb_postargs(rtype, atype, fn, arg, ...)		\
+	typesafe_cb_cast(rtype (*)(atype, __VA_ARGS__),			\
+			 rtype (*)(__typeof__(arg), __VA_ARGS__),	\
+			 (fn))
 #endif /* CCAN_CAST_IF_TYPE_H */