typesafe_cb: handle pointers to undefined struct types.

[ccan] / ccan / typesafe_cb / typesafe_cb.h

diff --git a/ccan/typesafe_cb/typesafe_cb.h b/ccan/typesafe_cb/typesafe_cb.h
index 98d0d4f058657e33b1406a620cce5ba04ef84251..f5e416de2de26c0e65605c5ed923ce0177cf4c33 100644 (file)
--- a/ccan/typesafe_cb/typesafe_cb.h
+++ b/ccan/typesafe_cb/typesafe_cb.h
@@ -4,9 +4,10 @@
 
 #if HAVE_TYPEOF && HAVE_BUILTIN_CHOOSE_EXPR && HAVE_BUILTIN_TYPES_COMPATIBLE_P
 /**
 
 #if HAVE_TYPEOF && HAVE_BUILTIN_CHOOSE_EXPR && HAVE_BUILTIN_TYPES_COMPATIBLE_P
 /**

- * cast_if_type - only cast an expression if it is of a given type
+ * cast_if_type - only cast an expression if test matches a given type

  * @desttype: the type to cast to
  * @expr: the expression to cast
  * @desttype: the type to cast to
  * @expr: the expression to cast

+ * @test: the expression to test

  * @oktype: the type we allow
  *
  * This macro is used to create functions which allow multiple types.
  * @oktype: the type we allow
  *
  * This macro is used to create functions which allow multiple types.


@@ -19,27 +20,28 @@
  *
  * This is merely useful for warnings: if the compiler does not
  * support the primitives required for cast_if_type(), it becomes an
  *
  * 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 @oktype argument is not used.  In
+ * 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.
  *
  * Example:
  *     // We can take either an unsigned long or a void *.
  *     void _set_some_value(void *val);
  * 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(expr)                    \
- *             _set_some_value(cast_if_type(void *, (expr), unsigned long))
+ *     #define set_some_value(e)                       \
+ *             _set_some_value(cast_if_type(void *, (e), (e), unsigned long))

  */
  */

-#define cast_if_type(desttype, expr, oktype)                           \
-__builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(expr):0), oktype), \
+#define cast_if_type(desttype, expr, test, oktype)                     \
+__builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(test):0), oktype), \

                        (desttype)(expr), (expr))
 #else
                        (desttype)(expr), (expr))
 #else

-#define cast_if_type(desttype, expr, oktype) ((desttype)(expr))
+#define cast_if_type(desttype, expr, test, oktype) ((desttype)(expr))

 #endif
 
 /**
  * cast_if_any - only cast an expression if it is one of the three given types
  * @desttype: the type to cast to
  * @expr: the expression to cast
 #endif
 
 /**
  * cast_if_any - only cast an expression if it is one of the three 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
  * @ok1: the first type we allow
  * @ok2: the second type we allow
  * @ok3: the third type we allow


@@ -52,13 +54,13 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(expr):0), oktype),
  *     // We can take either a long, unsigned long, void * or a const void *.
  *     void _set_some_value(void *val);
  *     #define set_some_value(expr)                                    \
  *     // 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),             \
+ *             _set_some_value(cast_if_any(void *, (expr), (expr),     \

  *                                         long, unsigned long, const void *))
  */
  *                                         long, unsigned long, const void *))
  */

-#define cast_if_any(desttype, expr, ok1, ok2, ok3)                     \
+#define cast_if_any(desttype, expr, test, ok1, ok2, ok3)               \

        cast_if_type(desttype,                                          \
                     cast_if_type(desttype,                             \
        cast_if_type(desttype,                                          \
                     cast_if_type(desttype,                             \

-                                 cast_if_type(desttype, (expr), ok1),  \
+                                 cast_if_type(desttype, (expr), (test), ok1), \

                                  ok2),                                 \
                     ok3)
 
                                  ok2),                                 \
                     ok3)
 


@@ -81,10 +83,7 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(expr):0), oktype),
  *             _register_callback(typesafe_cb(void, (fn), (arg)), (arg))
  */
 #define typesafe_cb(rtype, fn, arg)                    \
  *             _register_callback(typesafe_cb(void, (fn), (arg)), (arg))
  */
 #define typesafe_cb(rtype, fn, arg)                    \

-       cast_if_any(rtype (*)(void *), (fn),            \
-                   rtype (*)(typeof(*arg)*),           \
-                   rtype (*)(const typeof(*arg)*),     \
-                   rtype (*)(volatile typeof(*arg)*))
+       cast_if_type(rtype (*)(void *), (fn), (fn)(arg), rtype)

 
 /**
  * typesafe_cb_const - cast a const callback function if it matches the arg
 
 /**
  * typesafe_cb_const - cast a const callback function if it matches the arg


@@ -105,8 +104,9 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(expr):0), oktype),
  *             _register_callback(typesafe_cb_const(void, (fn), (arg)), (arg))
  */
 #define typesafe_cb_const(rtype, fn, arg)                              \
  *             _register_callback(typesafe_cb_const(void, (fn), (arg)), (arg))
  */
 #define typesafe_cb_const(rtype, fn, arg)                              \

-       cast_if_type(rtype (*)(const void *), (fn),                     \
-                    rtype (*)(const typeof(*arg)*))
+       sizeof((fn)((const void *)0)),                                  \
+               cast_if_type(rtype (*)(const void *),                   \
+                            (fn), (fn)(arg), rtype (*)(typeof(arg)))

 
 /**
  * typesafe_cb_preargs - cast a callback function if it matches the arg
 
 /**
  * typesafe_cb_preargs - cast a callback function if it matches the arg


@@ -124,11 +124,8 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(expr):0), oktype),
  *                                (arg))
  */
 #define typesafe_cb_preargs(rtype, fn, arg, ...)                       \
  *                                (arg))
  */
 #define typesafe_cb_preargs(rtype, fn, arg, ...)                       \

-       cast_if_any(rtype (*)(__VA_ARGS__, void *), (fn),               \
-                   rtype (*)(__VA_ARGS__, typeof(arg)),                \
-                   rtype (*)(__VA_ARGS__, const typeof(*arg) *),       \
-                   rtype (*)(__VA_ARGS__, volatile typeof(*arg) *))
-
+       cast_if_type(rtype (*)(__VA_ARGS__, void *), (fn), (fn),        \
+                    rtype (*)(__VA_ARGS__, typeof(arg)))

 /**
  * typesafe_cb_postargs - cast a callback function if it matches the arg
  * @rtype: the return type of the callback function
 /**
  * typesafe_cb_postargs - cast a callback function if it matches the arg
  * @rtype: the return type of the callback function


@@ -145,11 +142,8 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(expr):0), oktype),
  *                                (arg))
  */
 #define typesafe_cb_postargs(rtype, fn, arg, ...)                      \
  *                                (arg))
  */
 #define typesafe_cb_postargs(rtype, fn, arg, ...)                      \

-       cast_if_any(rtype (*)(void *, __VA_ARGS__), (fn),               \
-                   rtype (*)(typeof(arg), __VA_ARGS__),                \
-                   rtype (*)(const typeof(*arg) *, __VA_ARGS__),       \
-                   rtype (*)(volatile typeof(*arg) *, __VA_ARGS__))
-
+       cast_if_type(rtype (*)(void *, __VA_ARGS__), (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
 /**
  * typesafe_cb_cmp - cast a compare function if it matches the arg
  * @rtype: the return type of the callback function


@@ -161,7 +155,8 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(expr):0), oktype),
  * the callback provided takes two a const pointers to @arg.
  *
  * It is assumed that @arg is of pointer type: usually @arg is passed
  * 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.
+ * 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,
  *
  * Example:
  *     void _my_qsort(void *base, size_t nmemb, size_t size,