On 5/3/21 10:12 PM, Elijah Newren via GitGitGadget wrote:
> From: Elijah Newren <newren@xxxxxxxxx>
...
> Signed-off-by: Elijah Newren <newren@xxxxxxxxx>
> ---
> merge-ort.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 64 insertions(+), 2 deletions(-)
>
> diff --git a/merge-ort.c b/merge-ort.c
> index 5523fc9e86b3..a342cc6344fd 100644
> --- a/merge-ort.c
> +++ b/merge-ort.c
> @@ -140,6 +140,30 @@ struct rename_info {
> int callback_data_nr, callback_data_alloc;
> char *callback_data_traverse_path;
>
> + /*
> + * merge_trees: trees passed to the merge algorithm for the merge
> + *
> + * merge_trees records the trees passed to the merge algorithm. But,
> + * this data also is stored in merge_result->priv. If a sequence of
> + * merges are being done (such as when cherry-picking or rebasing),
> + * the next merge can look at this and re-use information from
> + * previous merges under certain cirumstances.
s/cirumstances/circumstances/
> + *
> + * See also all the cached_* variables.
> + */
> + struct tree *merge_trees[3];
> +
> + /*
> + * cached_pairs_valid_side: which side's cached info can be reused
> + *
> + * See the description for merge_trees. For repeated merges, at most
> + * only one side's cached information can be used. Valid values:
> + * MERGE_SIDE2: cached data from side2 can be reused
> + * MERGE_SIDE1: cached data from side1 can be reused
> + * 0: no cached data can be reused
> + */
> + int cached_pairs_valid_side;
...
> +static void merge_check_renames_reusable(struct merge_options *opt,
> + struct merge_result *result,
> + struct tree *merge_base,
> + struct tree *side1,
> + struct tree *side2)
> +{
> + struct rename_info *renames;
> + struct tree **merge_trees;
> + struct merge_options_internal *opti = result->priv;
> +
> + if (!opti)
> + return;
> +
> + renames = &opti->renames;
> + merge_trees = renames->merge_trees;
> + /* merge_trees[0..2] will only be NULL if opti is */
> + assert(merge_trees[0] && merge_trees[1] && merge_trees[2]);
> +
> + /* Check if we meet a condition for re-using cached_pairs */
> + if ( oideq(&merge_base->object.oid, &merge_trees[2]->object.oid) &&
> + oideq( &side1->object.oid, &result->tree->object.oid))
> + renames->cached_pairs_valid_side = MERGE_SIDE1;
> + else if (oideq(&merge_base->object.oid, &merge_trees[1]->object.oid) &&
> + oideq( &side2->object.oid, &result->tree->object.oid))
I see how you used whitespace to align the different items in these
conditions, but they are nonstandard so it's probably best to drop
the extra spaces.
> + renames->cached_pairs_valid_side = MERGE_SIDE2;
> + else
> + renames->cached_pairs_valid_side = 0; /* neither side valid */
> +}
> +
> /*** Function Grouping: merge_incore_*() and their internal variants ***/
>
> /*
> @@ -3949,7 +4002,16 @@ void merge_incore_nonrecursive(struct merge_options *opt,
>
> trace2_region_enter("merge", "merge_start", opt->repo);
> assert(opt->ancestor != NULL);
> + merge_check_renames_reusable(opt, result, merge_base, side1, side2);
> merge_start(opt, result);
> + /*
> + * Record the trees used in this merge, so if there's a next merge in
> + * a cherry-pick or rebase sequence it might be able to take advantage
> + * of the cached_pairs in that next merge.
> + */
> + opt->priv->renames.merge_trees[0] = merge_base;
> + opt->priv->renames.merge_trees[1] = side1;
> + opt->priv->renames.merge_trees[2] = side2;
> trace2_region_leave("merge", "merge_start", opt->repo);
>
Again, the functionality seems reasonable. We're not quite to the
punchline of the series.
Thanks,
-Stolee
