[PATCH 0/4] hash: introduce generic wrappers to update hash contexts

[Patrick Steinhardt <ps@pks.im>]

Hi,

this patch series introduces a couple of generic wrappers to update hash
contexts. Instead of updating contexts via function pointers provided by
the hash algorithm, we now remember the hash algorithm in the context
itself. As a result, subsequent calls that update the hash don't need to
remember which algorithm they used:

    ```
    struct git_hash_ctx ctx;
    struct object_id oid;

    git_hash_sha1_init(&ctx);
    git_hash_update(&ctx, data);
    git_hash_final_oid(&oid, &ctx);
    ```

This was discussed in [1] and [2].

The series is built on top of master at 3b0d05c4a7 (The fifth batch,
2025-01-29) with tb/unsafe-hashtcleanup at 04292c3796 (hash.h: drop
unsafe_ function variants, 2025-01-23) merged into it.

Thanks!

Patrick

[1]: <Z3fhK1ACzJfVehM2@pks.im>
[2]: <Z4jyZCAwqOjZ-u2U@pks.im>

---
Patrick Steinhardt (4):
      hash: convert hashing context to a structure
      hash: stop typedeffing the hash context
      hash: provide generic wrappers to update hash contexts
      global: adapt callers to use generic hash context helpers

 builtin/fast-import.c      |  16 +++---
 builtin/index-pack.c       |  19 ++++---
 builtin/patch-id.c         |  14 ++---
 builtin/receive-pack.c     |  18 +++----
 builtin/unpack-objects.c   |  13 +++--
 bulk-checkin.c             |  10 ++--
 csum-file.c                |  16 +++---
 csum-file.h                |   4 +-
 diff.c                     |  34 ++++++------
 diff.h                     |   2 +-
 hash.h                     |  43 +++++++++++----
 http-push.c                |   6 +--
 http.c                     |   6 +--
 http.h                     |   2 +-
 object-file.c              | 130 +++++++++++++++++++++++----------------------
 pack-check.c               |   6 +--
 pack-write.c               |  16 +++---
 read-cache.c               |  26 ++++-----
 rerere.c                   |  18 +++----
 t/helper/test-hash-speed.c |   8 +--
 t/helper/test-hash.c       |   6 +--
 t/unit-tests/u-hash.c      |   6 +--
 trace2/tr2_sid.c           |   6 +--
 23 files changed, 224 insertions(+), 201 deletions(-)


---
base-commit: 16b8e620c866ddbff7e33cc47b9772541285da7f
change-id: 20250131-b4-pks-hash-context-direct-aa7acfda3abc