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authorJeff King <peff@peff.net>2014-07-13 02:42:03 -0400
committerJunio C Hamano <gitster@pobox.com>2014-07-13 18:59:05 -0700
commit8ff226a9d5ee065fe52752e6032f63cb6e4beccb (patch)
tree7076defdcbf14d7abf9d1ce8fc4e37663e0b8f8a /object.c
parent5af01caa08700e389d49a81be15c7413abd4aa69 (diff)
downloadgit-8ff226a9d5ee065fe52752e6032f63cb6e4beccb.tar.gz
add object_as_type helper for casting objects
When we call lookup_commit, lookup_tree, etc, the logic goes something like: 1. Look for an existing object struct. If we don't have one, allocate and return a new one. 2. Double check that any object we have is the expected type (and complain and return NULL otherwise). 3. Convert an object with type OBJ_NONE (from a prior call to lookup_unknown_object) to the expected type. We can encapsulate steps 2 and 3 in a helper function which checks whether we have the expected object type, converts OBJ_NONE as appropriate, and returns the object. Not only does this shorten the code, but it also provides one central location for converting OBJ_NONE objects into objects of other types. Future patches will use that to enforce type-specific invariants. Since this is a refactoring, we would want it to behave exactly as the current code. It takes a little reasoning to see that this is the case: - for lookup_{commit,tree,etc} functions, we are just pulling steps 2 and 3 into a function that does the same thing. - for the call in peel_object, we currently only do step 3 (but we want to consolidate it with the others, as mentioned above). However, step 2 is a noop here, as the surrounding conditional makes sure we have OBJ_NONE (which we want to keep to avoid an extraneous call to sha1_object_info). - for the call in lookup_commit_reference_gently, we are currently doing step 2 but not step 3. However, step 3 is a noop here. The object we got will have just come from deref_tag, which must have figured out the type for each object in order to know when to stop peeling. Therefore the type will never be OBJ_NONE. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'object.c')
-rw-r--r--object.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/object.c b/object.c
index 472aa8d5be..b2319f6246 100644
--- a/object.c
+++ b/object.c
@@ -158,6 +158,23 @@ void *create_object(const unsigned char *sha1, void *o)
return obj;
}
+void *object_as_type(struct object *obj, enum object_type type, int quiet)
+{
+ if (obj->type == type)
+ return obj;
+ else if (obj->type == OBJ_NONE) {
+ obj->type = type;
+ return obj;
+ }
+ else {
+ if (!quiet)
+ error("object %s is a %s, not a %s",
+ sha1_to_hex(obj->sha1),
+ typename(obj->type), typename(type));
+ return NULL;
+ }
+}
+
struct object *lookup_unknown_object(const unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);