[PATCH 18/24] pack-bitmap: implement test helpers for pseudo-merge

[Taylor Blau <me@ttaylorr.com>]

Implement three new sub-commands for the "bitmap" test-helper:

  - t/helper test-tool bitmap dump-pseudo-merges
  - t/helper test-tool bitmap dump-pseudo-merge-commits <n>
  - t/helper test-tool bitmap dump-pseudo-merge-objects <n>

These three helpers dump the list of pseudo merges, the "parents" of the
nth pseudo-merges, and the set of objects reachable from those parents,
respectively.

These helpers will be useful in subsequent patches when we add test
coverage for pseudo-merge bitmaps.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 pack-bitmap.c          | 126 +++++++++++++++++++++++++++++++++++++++++
 pack-bitmap.h          |   3 +
 t/helper/test-bitmap.c |  34 ++++++++---
 3 files changed, 156 insertions(+), 7 deletions(-)

diff --git a/pack-bitmap.c b/pack-bitmap.c
index e0f191b7581..7188dd75eaf 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -2442,6 +2442,132 @@ int test_bitmap_hashes(struct repository *r)
 	return 0;
 }
 
+static void bit_pos_to_object_id(struct bitmap_index *bitmap_git,
+				 uint32_t bit_pos,
+				 struct object_id *oid)
+{
+	uint32_t index_pos;
+
+	if (bitmap_is_midx(bitmap_git))
+		index_pos = pack_pos_to_midx(bitmap_git->midx, bit_pos);
+	else
+		index_pos = pack_pos_to_index(bitmap_git->pack, bit_pos);
+
+	nth_bitmap_object_oid(bitmap_git, oid, index_pos);
+}
+
+int test_bitmap_pseudo_merges(struct repository *r)
+{
+	struct bitmap_index *bitmap_git;
+	uint32_t i;
+
+	bitmap_git = prepare_bitmap_git(r);
+	if (!bitmap_git || !bitmap_git->pseudo_merges.nr)
+		goto cleanup;
+
+	for (i = 0; i < bitmap_git->pseudo_merges.nr; i++) {
+		struct pseudo_merge *merge;
+		struct ewah_bitmap *commits_bitmap, *merge_bitmap;
+
+		merge = use_pseudo_merge(&bitmap_git->pseudo_merges,
+					 &bitmap_git->pseudo_merges.v[i]);
+		commits_bitmap = merge->commits;
+		merge_bitmap = pseudo_merge_bitmap(&bitmap_git->pseudo_merges,
+						   merge);
+
+		printf("at=%"PRIuMAX", commits=%"PRIuMAX", objects=%"PRIuMAX"\n",
+		       (uintmax_t)merge->at,
+		       (uintmax_t)ewah_bitmap_popcount(commits_bitmap),
+		       (uintmax_t)ewah_bitmap_popcount(merge_bitmap));
+	}
+
+cleanup:
+	free_bitmap_index(bitmap_git);
+	return 0;
+}
+
+static void dump_ewah_object_ids(struct bitmap_index *bitmap_git,
+				 struct ewah_bitmap *bitmap)
+
+{
+	struct ewah_iterator it;
+	eword_t word;
+	uint32_t pos = 0;
+
+	ewah_iterator_init(&it, bitmap);
+
+	while (ewah_iterator_next(&word, &it)) {
+		struct object_id oid;
+		uint32_t offset;
+
+		for (offset = 0; offset < BITS_IN_EWORD; offset++) {
+			if (!(word >> offset))
+				break;
+
+			offset += ewah_bit_ctz64(word >> offset);
+
+			bit_pos_to_object_id(bitmap_git, pos + offset, &oid);
+			printf("%s\n", oid_to_hex(&oid));
+		}
+		pos += BITS_IN_EWORD;
+	}
+}
+
+int test_bitmap_pseudo_merge_commits(struct repository *r, uint32_t n)
+{
+	struct bitmap_index *bitmap_git;
+	struct pseudo_merge *merge;
+	int ret = 0;
+
+	bitmap_git = prepare_bitmap_git(r);
+	if (!bitmap_git || !bitmap_git->pseudo_merges.nr)
+		goto cleanup;
+
+	if (n >= bitmap_git->pseudo_merges.nr) {
+		ret = error(_("pseudo-merge index out of range "
+			      "(%"PRIu32" >= %"PRIuMAX")"),
+			    n, (uintmax_t)bitmap_git->pseudo_merges.nr);
+		goto cleanup;
+	}
+
+	merge = use_pseudo_merge(&bitmap_git->pseudo_merges,
+				 &bitmap_git->pseudo_merges.v[n]);
+	dump_ewah_object_ids(bitmap_git, merge->commits);
+
+cleanup:
+	free_bitmap_index(bitmap_git);
+	return ret;
+}
+
+int test_bitmap_pseudo_merge_objects(struct repository *r, uint32_t n)
+{
+	struct bitmap_index *bitmap_git;
+	struct pseudo_merge *merge;
+	int ret = 0;
+
+	bitmap_git = prepare_bitmap_git(r);
+	if (!bitmap_git || !bitmap_git->pseudo_merges.nr)
+		goto cleanup;
+
+	if (n >= bitmap_git->pseudo_merges.nr) {
+		ret = error(_("pseudo-merge index out of range "
+			      "(%"PRIu32" >= %"PRIuMAX")"),
+			    n, (uintmax_t)bitmap_git->pseudo_merges.nr);
+		goto cleanup;
+	}
+
+	merge = use_pseudo_merge(&bitmap_git->pseudo_merges,
+				 &bitmap_git->pseudo_merges.v[n]);
+
+	dump_ewah_object_ids(bitmap_git,
+			     pseudo_merge_bitmap(&bitmap_git->pseudo_merges,
+						 merge));
+
+cleanup:
+	free_bitmap_index(bitmap_git);
+	return ret;
+}
+
 int rebuild_bitmap(const uint32_t *reposition,
 		   struct ewah_bitmap *source,
 		   struct bitmap *dest)
diff --git a/pack-bitmap.h b/pack-bitmap.h
index a5fe4f305ef..25d3b8e604a 100644
--- a/pack-bitmap.h
+++ b/pack-bitmap.h
@@ -73,6 +73,9 @@ void traverse_bitmap_commit_list(struct bitmap_index *,
 void test_bitmap_walk(struct rev_info *revs);
 int test_bitmap_commits(struct repository *r);
 int test_bitmap_hashes(struct repository *r);
+int test_bitmap_pseudo_merges(struct repository *r);
+int test_bitmap_pseudo_merge_commits(struct repository *r, uint32_t n);
+int test_bitmap_pseudo_merge_objects(struct repository *r, uint32_t n);
 
 #define GIT_TEST_PACK_USE_BITMAP_BOUNDARY_TRAVERSAL \
 	"GIT_TEST_PACK_USE_BITMAP_BOUNDARY_TRAVERSAL"
diff --git a/t/helper/test-bitmap.c b/t/helper/test-bitmap.c
index af43ee1cb5e..6af2b42678f 100644
--- a/t/helper/test-bitmap.c
+++ b/t/helper/test-bitmap.c
@@ -13,21 +13,41 @@ static int bitmap_dump_hashes(void)
 	return test_bitmap_hashes(the_repository);
 }
 
+static int bitmap_dump_pseudo_merges(void)
+{
+	return test_bitmap_pseudo_merges(the_repository);
+}
+
+static int bitmap_dump_pseudo_merge_commits(uint32_t n)
+{
+	return test_bitmap_pseudo_merge_commits(the_repository, n);
+}
+
+static int bitmap_dump_pseudo_merge_objects(uint32_t n)
+{
+	return test_bitmap_pseudo_merge_objects(the_repository, n);
+}
+
 int cmd__bitmap(int argc, const char **argv)
 {
 	setup_git_directory();
 
-	if (argc != 2)
-		goto usage;
-
-	if (!strcmp(argv[1], "list-commits"))
+	if (argc == 2 && !strcmp(argv[1], "list-commits"))
 		return bitmap_list_commits();
-	if (!strcmp(argv[1], "dump-hashes"))
+	if (argc == 2 && !strcmp(argv[1], "dump-hashes"))
 		return bitmap_dump_hashes();
+	if (argc == 2 && !strcmp(argv[1], "dump-pseudo-merges"))
+		return bitmap_dump_pseudo_merges();
+	if (argc == 3 && !strcmp(argv[1], "dump-pseudo-merge-commits"))
+		return bitmap_dump_pseudo_merge_commits(atoi(argv[2]));
+	if (argc == 3 && !strcmp(argv[1], "dump-pseudo-merge-objects"))
+		return bitmap_dump_pseudo_merge_objects(atoi(argv[2]));
 
-usage:
 	usage("\ttest-tool bitmap list-commits\n"
-	      "\ttest-tool bitmap dump-hashes");
+	      "\ttest-tool bitmap dump-hashes\n"
+	      "\ttest-tool bitmap dump-pseudo-merges\n"
+	      "\ttest-tool bitmap dump-pseudo-merge-commits <n>\n"
+	      "\ttest-tool bitmap dump-pseudo-merge-objects <n>");
 
 	return -1;
 }
-- 
2.44.0.303.g1dc5e5b124c