merge-ort: avoid repeating fill_tree_descriptor() on the same tree
Three-way merges, by their nature, are going to often have two or more trees match at a given subdirectory. We can avoid calling fill_tree_descriptor() on the same tree by checking when these trees match. Noting when various oids match will also be useful in other calculations and optimizations as well. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Elijah Newren committed
Dec 13, 2020 at 08:04 UTC
885f0063e9962068d381ca5256ca49070bb2480c
1 file changed
+22
-4
merge-ort.c
+22
-4
@@ -223,6 +223,15 @@ static int collect_merge_info_callback(int n,
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unsigned mbase_null = !(mask & 1);
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unsigned side1_null = !(mask & 2);
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unsigned side2_null = !(mask & 4);
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+ unsigned side1_matches_mbase = (!side1_null && !mbase_null &&
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+ names[0].mode == names[1].mode &&
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+ oideq(&names[0].oid, &names[1].oid));
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+ unsigned side2_matches_mbase = (!side2_null && !mbase_null &&
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+ names[0].mode == names[2].mode &&
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+ oideq(&names[0].oid, &names[2].oid));
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+ unsigned sides_match = (!side1_null && !side2_null &&
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+ names[1].mode == names[2].mode &&
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+ oideq(&names[1].oid, &names[2].oid));
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/* n = 3 is a fundamental assumption. */
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if (n != 3)
@@ -275,10 +284,19 @@ static int collect_merge_info_callback(int n,
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newinfo.pathlen = st_add3(newinfo.pathlen, p->pathlen, 1);
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for (i = MERGE_BASE; i <= MERGE_SIDE2; i++) {
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- const struct object_id *oid = NULL;
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- if (dirmask & 1)
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- oid = &names[i].oid;
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- buf[i] = fill_tree_descriptor(opt->repo, t + i, oid);
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+ if (i == 1 && side1_matches_mbase)
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+ t[1] = t[0];
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+ else if (i == 2 && side2_matches_mbase)
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+ t[2] = t[0];
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+ else if (i == 2 && sides_match)
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+ t[2] = t[1];
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+ else {
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+ const struct object_id *oid = NULL;
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+ if (dirmask & 1)
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+ oid = &names[i].oid;
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+ buf[i] = fill_tree_descriptor(opt->repo,
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+ t + i, oid);
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+ }
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dirmask >>= 1;
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}
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