Re: [Libguestfs] [PATCH libnbd v2 02/10] lib: Add macros to check if a callback is "null" or not, and set it to null.

We have defined the concept of a "null callback" meaning one where the .callback field = NULL. The first two new macros just test this property, and the third one sets a callback to null. This change is neutral refactoring. --- generator/generator | 4 ++-- generator/states-reply-simple.c | 2 +- generator/states-reply-structured.c | 11 ++++++----- generator/states-reply.c | 2 +- generator/states.c | 2 +- lib/debug.c | 2 +- lib/internal.h | 9 +++++++-- 7 files changed, 19 insertions(+), 13 deletions(-) diff --git a/generator/generator b/generator/generator index ca97910..98c99e0 100755 --- a/generator/generator +++ b/generator/generator @@ -3576,7 +3576,7 @@ let generate_lib_api_c () = let value = match errcode with | Some value -> value | None -> assert false in - pr " if (%s_callback.callback == NULL) {\n" cbname; + pr " if (CALLBACK_IS_NULL (%s_callback)) {\n" cbname;

+++ b/lib/internal.h @@ -273,6 +273,11 @@ struct command { uint32_t error; /* Local errno value */ }; +/* Test if a callback is "null" or not, and set it to null. */ +#define CALLBACK_IS_NULL(cb) ((cb).callback == NULL) +#define CALLBACK_IS_NOT_NULL(cb) (! CALLBACK_IS_NULL ((cb)))

+#define SET_CALLBACK_TO_NULL(cb) ((cb).callback = NULL) + /* Call a callback. */ #define CALL_CALLBACK(cb, ...) \ (cb).callback ((cb).user_data, ##__VA_ARGS__) @@ -286,9 +291,9 @@ struct command { #define FREE_CALLBACK(cb) \ do { \ nbd_completion_callback *_cb = (nbd_completion_callback *)&(cb); \ - if (_cb->callback != NULL && _cb->free != NULL) \ + if (CALLBACK_IS_NOT_NULL (cb) && _cb->free != NULL) \ _cb->free (_cb->user_data); \ - _cb->callback = NULL; \ + SET_CALLBACK_TO_NULL (cb); \ } while (0) /* aio.c */