Since IdIndex is immutable, we don't need fast insertion provided by BTreeMap.
Let's simply use Vec for some speed up. More importantly, this allows us to
store multiple (ChangeId, CommitId) pairs for the same change id, and will
unblock the use of IdIndex in revset::resolve_symbol().
Some benchmark numbers (against my "linux" repo) follow.
Command:
hyperfine --warmup 3 "jj log -r master \
-T 'commit_id.short_prefix_and_brackets()' \
--no-commit-working-copy --no-graph"
Original:
Time (mean ± σ): 1.892 s ± 0.031 s [User: 1.800 s, System: 0.092 s]
Range (min … max): 1.833 s … 1.935 s 10 runs
This commit:
Time (mean ± σ): 867.5 ms ± 2.7 ms [User: 809.9 ms, System: 57.7 ms]
Range (min … max): 862.3 ms … 871.0 ms 10 runs
I think this is a remainder of 68ad712e12 "Templater: Combine Change and
Commit id templates." It doesn't make sense that description.short() prints
the first 12 characters.
With my "jj" work repo, this saves ~4ms to show the log with default revset.
Command:
JJ_CONFIG=/dev/null hyperfine --warmup 3 --runs 100 \
"jj log -T 'commit_id.short_prefix_and_brackets() \
change_id.short_prefix_and_brackets()' \
--no-commit-working-copy"
Baseline (a7541e1ba4):
Time (mean ± σ): 54.1 ms ± 16.4 ms [User: 46.4 ms, System: 7.8 ms]
Range (min … max): 36.5 ms … 78.1 ms 100 runs
This commit:
Time (mean ± σ): 49.5 ms ± 16.4 ms [User: 42.4 ms, System: 7.2 ms]
Range (min … max): 31.4 ms … 70.9 ms 100 runs
This iterator will be used to merge neighbor commit ids across segments.
resolve_prefix() is simplified to non-short-circuiting loop. I think that's
fine because visiting parents is cheap, and the costly operation here is
segment_resolve_prefix().
entry_by_pos() could also be migrated to iterator, but I leave the unsafe
bits there.
ReadonlyIndex implementation leverages the existing binary search
function. MutableIndex one is basically the same as repo::IdIndex.
Shortest prefix length could be calculated for each segment, but I think
returning neighbors is better for testing.
This is ugly, but we need a special case because root_change_id and
root_commit_id aren't equal but share the same prefix bytes. In practice,
no one would care for the shortest root id prefix, but we'll need to deal
with a similar problem when migrating prefix id resolution to repo layer.
This helps us to migrate commit_id index to ReadonlyIndex. For large
repositories, this also reduces initialization cost, but that's not the main
intent of this change.
https://github.com/martinvonz/jj/pull/1041#issuecomment-1399225876
common_hex_len() and iter_half_bytes() are added to backend.rs since more
call sites will be added to index.rs, and I feel index.rs isn't a good place
to host this kind of utility functions.
I made it a free function. Alternatively, the root id could be instantiated
by and obtained through backend, but I don't think we'll need such level of
abstraction.
I'm going to add a workaround for shortest prefix calculation of the root ids,
where this function will be used.
The flake currently has some odd behavior, such as copying .jj and
target/, and treating the jj src as an input to the dev shell. This
avoids making life rough for direnv users while those are outstanding.
Make op resolution a closed operation, powered by a callback provided by the
caller which runs under an internal lock scope. This allows for greatly
simplifying the internal lifetime structuring.
If commit_id[..prefix_len] < prefix, commit_id < prefix is obviously true.
If commit_id[..prefix_len] == prefix, commit_id < prefix returns false. So
slicing isn't needed.
This makes commit_id_byte_prefix_to_pos() basically the same as
segment_commit_id_to_pos(), and these two functions can be merged.
matches() is called from resolve_change_id() loop right now, so it's better to
not allocate String there. Regarding new IdIndex integration, I'll probably make
IdIndex store raw byte ids instead of hexes, and use HexPrefix to look up
range and test prefixes. I think this is basically the same as prefix lookup
in MutableIndex, but I have no idea if we can factor out a common interface.
I made HexPrefix store (Vec<u8>, bool) instead of (Vec<u8>, Option<u8>) so
both min/partial prefixes can be borrowed as slice.
I think the intent of '- 1' here is the separator length, which was
originally ':'. Alternatively, we can ensure that prefix + remainder is
always 12 chars.
It's unlikely we'll need to discriminate commit/change id types while
templating, so let's unify them. Since ObjectId trait isn't object safe,
I decided to simply store bytes instead of Box<dyn ObjectId>.
It seems that at least examples are not included in the default set of
targets, and we clearly want to check that the examples compile, as
that's an important reason we have them. We don't have any tests for
the examples yet, but let's add the flag now so we don't forget it
later.
This gets used by `nix develop`, or automatically by `direnv` if you have it
installed.
The binary versions are pinned to the versions recommended by `contributing.md`.
```
>> cargo --version
cargo 1.60.0 (d1fd9fe 2022-03-01)
>> rustc --version
rustc 1.60.0 (7737e0b5c 2022-04-04)
>> cargo fmt --version
rustfmt 1.5.1-nightly (3984bc5 2023-01-17)
>> cargo clippy --version
clippy 0.1.60 (7737e0b 2022-04-04)
```
Our internal build at Google needs a custom global flag, which lets
the user pass flags into C++ code we use for our custom backends. This
provides a way of achieving that.
