git/packfile.c, branch v2.51.2

midx: remove now-unused linked list of multi-pack indices

2025-07-15T19:07:30Z

In the preceding commits we have migrated all users of the linked list of multi-pack indices to instead use those stored in the object database sources. Remove those now-unused pointers. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

packfile: stop using linked MIDX list in `get_all_packs()`

2025-07-15T19:07:30Z

Refactor `get_all_packs()` so that we stop using the linked list of multi-pack indices. Note that there is no need to explicitly prepare alternates, and neither do we have to use `get_multi_pack_index()`, because `prepare_packed_git()` already takes care of populating all data structures for us. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

packfile: stop using linked MIDX list in `find_pack_entry()`

2025-07-15T19:07:29Z

Refactor `find_pack_entry()` so that we stop using the linked list of multi-pack indices. Note that there is no need to explicitly prepare alternates, and neither do we have to use `get_multi_pack_index()`, because `prepare_packed_git()` already takes care of populating all data structures for us. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

packfile: refactor `get_multi_pack_index()` to work on sources

2025-07-15T19:07:29Z

The function `get_multi_pack_index()` loads multi-pack indices via `prepare_packed_git()` and then returns the linked list of multi-pack indices that is stored in `struct object_database`. That list is in the process of being removed though in favor of storing the MIDX as part of the object database source it belongs to. Refactor `get_multi_pack_index()` so that it returns the multi-pack index for a single object source. Callers are now expected to call this function for each source they are interested in. This requires them to iterate through alternates, so we have to prepare alternate object sources before doing so. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

midx: stop using linked list when closing MIDX

2025-07-15T19:07:29Z

When calling `close_midx()` we not only close the multi-pack index for one object source, but instead we iterate through the whole linked list of MIDXs to close all of them. This linked list is about to go away in favor of using the new per-source pointer to its respective MIDX. Refactor the function to iterate through sources instead. Note that after this patch, there's a couple of callsites left that continue to use `close_midx()` without iterating through all sources. These are all cases where we don't care about the MIDX from other sources though, so it's fine to keep them as-is. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

packfile: refactor `prepare_packed_git_one()` to work on sources

2025-07-15T19:07:28Z

In the preceding commit we refactored how we load multi-pack indices to take a corresponding "source" as input. As part of this refactoring we started to store a pointer to the MIDX in `struct odb_source` itself. Refactor loading of packfiles in the same way: instead of passing in the object directory, we now pass in the source from which we want to load packfiles. This allows us to simplify the code because we don't have to search for a corresponding MIDX anymore, but we can instead directly use the MIDX that we have already prepared beforehand. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

midx: start tracking per object database source

2025-07-15T19:07:28Z

Multi-pack indices are tracked via `struct multi_pack_index`. This data structure is stored as a linked list inside `struct object_database`, which is the global database that spans across all of the object sources. This layout causes two problems: - Object databases consist of multiple object sources (e.g. one source per alternate object directory), where each multi-pack index is specific to one of those sources. Regardless of that though, the MIDX is not tracked per source, but tracked globally for the whole object database. This creates a mismatch between the on-disk layout and how things are organized in the object database subsystems and makes some parts, like figuring out whether a source has an MIDX, quite awkward. - Multi-pack indices are an implementation detail of how efficient access for packfiles work. As such, they are neither relevant in the context of loose objects, nor in a potential future where we have pluggable backends. Refactor `prepare_multi_pack_index_one()` so that it works on a specific source, which allows us to easily store a pointer to the multi-pack index inside of it. For now, this pointer exists next to the existing linked list we have in the object database. Users will be adjusted in subsequent patches to instead use the per-source pointers. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

odb: rename `oid_object_info()`

2025-07-01T21:46:37Z

Rename `oid_object_info()` to `odb_read_object_info()` as well as their `_extended()` variant to match other functions related to the object database and our modern coding guidelines. Introduce compatibility wrappers so that any in-flight topics will continue to compile. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

odb: get rid of `the_repository` when handling alternates

2025-07-01T21:46:36Z

The functions to manage alternates all depend on `the_repository`. Refactor them to accept an object database as a parameter and adjust all callers. The functions are renamed accordingly. Note that right now the situation is still somewhat weird because we end up using the object store path provided by the object store's repository anyway. Consequently, we could have instead passed in a pointer to the repository instead of passing in the pointer to the object store. This will be addressed in subsequent commits though, where we will start to use the path owned by the object store itself. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

object-store: rename files to "odb.{c,h}"

2025-07-01T21:46:34Z

In the preceding commits we have renamed the structures contained in "object-store.h" to `struct object_database` and `struct odb_backend`. As such, the code files "object-store.{c,h}" are confusingly named now. Rename them to "odb.{c,h}" accordingly. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano