On Mon, Jan 09, 2023 at 10:09:32AM -0500, Derrick Stolee wrote:
> I did think that requiring callers to create their own object_info
> structs (which takes at least four lines) would be too much, but
> the number of new callers is so low that I think this is a fine place
> to stop.
Yeah, that was my feeling. I do wonder if there's a way to make it
easier for callers of oid_object_info_extended(), but I couldn't come up
with anything that's nice enough to merit the complexity.
For example, here's an attempt to let the caller use designated
initializers to set up the query struct:
diff --git a/object-file.c b/object-file.c
index 80b08fc389..60ca75d755 100644
--- a/object-file.c
+++ b/object-file.c
@@ -1700,13 +1700,12 @@ void *repo_read_object_file(struct repository *r,
enum object_type *type,
unsigned long *size)
{
- struct object_info oi = OBJECT_INFO_INIT;
unsigned flags = OBJECT_INFO_DIE_IF_CORRUPT | OBJECT_INFO_LOOKUP_REPLACE;
void *data;
+ struct object_info oi = OBJECT_INFO(.typep = type,
+ .sizep = size,
+ .contentp = &data);
- oi.typep = type;
- oi.sizep = size;
- oi.contentp = &data;
if (oid_object_info_extended(r, oid, &oi, flags))
return NULL;
diff --git a/object-store.h b/object-store.h
index 1a713d89d7..e894cee61b 100644
--- a/object-store.h
+++ b/object-store.h
@@ -418,7 +418,8 @@ struct object_info {
* Initializer for a "struct object_info" that wants no items. You may
* also memset() the memory to all-zeroes.
*/
-#define OBJECT_INFO_INIT { 0 }
+#define OBJECT_INFO(...) { 0, __VA_ARGS__ }
+#define OBJECT_INFO_INIT OBJECT_INFO()
/* Invoke lookup_replace_object() on the given hash */
#define OBJECT_INFO_LOOKUP_REPLACE 1
But:
- it actually triggers a gcc warning, since OBJECT_INFO(.typep = foo)
sets typep twice (once for the default "0", and once by name). In
this case the "0" is superfluous, since that's the default, and we
could just do:
#define OBJECT_INFO(...) { __VA_ARGS__ }
#define OBJECT_INFO_INIT OBJECT_INFO(0)
but I was hoping to find a general technique for object
initializers.
- it's not really that much shorter than the existing code. The real
benefit of "data = read_object(oid, type, size)" is the implicit
number and names of the parameters. And the way to get that is to
provide an extra function.
So I think we are better off with the code that is longer but totally
obvious, unless we really want to add a function wrapper for common
queries as syntactic sugar.
-Peff
