# [QUESTION] how to quickly find an oid in the git repository 3 messages from 2021-05-30 to 2021-05-31. Participants: ZheNing Hu, Jeff King. Thread: https://gitlist.dev/t/55802 ## ZheNing Hu, 2021-05-30 06:53 Subject: [QUESTION] how to quickly find an oid in the git repository Message-ID: URL: https://gitlist.dev/e/CAOLTT8SS8Wypho7eCCGH7LtOLwM6tWCzp8mGGEVASBC80MwJ5A%40mail.gmail.com ``` When I tried to make cat-file --batch use ref-filter logic, I encountered this problem: get_oid_with_context() does not really let me know if an oid is in the git repository. E.g. get_oid_with_context(the_repository, "0000000000000000000000000000000000000000",...) will return FOUND. (I really want it to tell me MISSING_OBJECT or something else) On the other hand, oid_object_info_extended() will parse an object in depth, using it will seriously affect performance. So I want to know if there is a function that can quickly find the oid? I searched in `object-name.c`, `object-file.c`, and there seems to be no clue... -- ZheNing Hu ``` ## Jeff King, 2021-05-30 20:54 Subject: Re: [QUESTION] how to quickly find an oid in the git repository Message-ID: URL: https://gitlist.dev/e/YLP7kuFNfVZK%2BxCK%40coredump.intra.peff.net In-Reply-To: ``` On Sun, May 30, 2021 at 02:53:24PM +0800, ZheNing Hu wrote: > When I tried to make cat-file --batch use ref-filter logic, > I encountered this problem: > > get_oid_with_context() does not really let me know > if an oid is in the git repository. E.g. > > get_oid_with_context(the_repository, > "0000000000000000000000000000000000000000",...) > > will return FOUND. (I really want it to tell me MISSING_OBJECT > or something else) Right, it's purely a name->oid lookup. > On the other hand, oid_object_info_extended() will parse an object > in depth, using it will seriously affect performance. So I want to know > if there is a function that can quickly find the oid? I searched in > `object-name.c`, `object-file.c`, and there seems to be no clue... You should be able to use oid_object_info_extended() here. It will try to do as little work as possible to fulfill the items requested in the object_info struct. So a blank one (or even passing NULL) will return an error if the object doesn't exist, but not otherwise. There's also has_object_file(), which is essentially a wrapper for this. -Peff ``` ## ZheNing Hu, 2021-05-31 11:30 Subject: Re: [QUESTION] how to quickly find an oid in the git repository Message-ID: URL: https://gitlist.dev/e/CAOLTT8Rsy-XRys6fv3EbUJSUbHFCG4%3Dw9uR7Bz8N8u8PWHgPhw%40mail.gmail.com In-Reply-To: ``` Jeff King 于2021年5月31日周一 上午4:54写道： > > On the other hand, oid_object_info_extended() will parse an object > > in depth, using it will seriously affect performance. So I want to know > > if there is a function that can quickly find the oid? I searched in > > `object-name.c`, `object-file.c`, and there seems to be no clue... > > You should be able to use oid_object_info_extended() here. It will try > to do as little work as possible to fulfill the items requested in the > object_info struct. So a blank one (or even passing NULL) will return an > error if the object doesn't exist, but not otherwise. > > There's also has_object_file(), which is essentially a wrapper for this. > This is exactly what I want. It seems that the real performance problem is not because of the use of oid_object_info_extended(), but the possible copy of the object data in it. > -Peff Thanks! -- ZheNing Hu ```