pack-bitmap: remember pseudo-merge parents

write_pseudo_merges() currently builds an array of temporary bitmaps for
the parent set of each pseudo-merge, then serializes those bitmaps later
while writing the extension.

Move those parent bitmaps onto the corresponding bitmapped_commit
entries instead. This keeps the on-disk output unchanged, but gives the
parent bitmap the same lifetime and access pattern that later changes
will use when pseudo-merge object bitmaps are built before the write
step.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index 66282ea14b51237edbc2cbe86f695687d2602d91..8200aed610135b394bd3287be5edfdf3bd4c443e 100644 (file)
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -32,6 +32,7 @@ struct bitmapped_commit {
        struct commit *commit;
        struct ewah_bitmap *bitmap;
        struct ewah_bitmap *write_as;
+       struct ewah_bitmap *pseudo_merge_parents;
        int flags;
        int xor_offset;
        uint32_t commit_pos;
@@ -102,6 +103,7 @@ void bitmap_writer_free(struct bitmap_writer *writer)
                if (bc->write_as != bc->bitmap)
                        ewah_free(bc->write_as);
                ewah_free(bc->bitmap);
+               ewah_free(bc->pseudo_merge_parents);
        }
        free(writer->selected);
 }
@@ -210,6 +212,7 @@ void bitmap_writer_push_commit(struct bitmap_writer *writer,
        writer->selected[writer->selected_nr].write_as = NULL;
        writer->selected[writer->selected_nr].flags = 0;
        writer->selected[writer->selected_nr].pseudo_merge = pseudo_merge;
+       writer->selected[writer->selected_nr].pseudo_merge_parents = NULL;
 
        writer->selected_nr++;
 }
@@ -1004,42 +1007,47 @@ static void write_pseudo_merges(struct bitmap_writer *writer,
                                struct hashfile *f)
 {
        struct oid_array commits = OID_ARRAY_INIT;
-       struct bitmap **commits_bitmap = NULL;
        off_t *pseudo_merge_ofs = NULL;
        off_t start, table_start, next_ext;
 
        uint32_t base = bitmap_writer_nr_selected_commits(writer);
        size_t i, j = 0;
 
-       CALLOC_ARRAY(commits_bitmap, writer->pseudo_merges_nr);
        CALLOC_ARRAY(pseudo_merge_ofs, writer->pseudo_merges_nr);
 
        for (i = 0; i < writer->pseudo_merges_nr; i++) {
                struct bitmapped_commit *merge = &writer->selected[base + i];
                struct commit_list *p;
+               struct bitmap *parents = bitmap_new();
 
                if (!merge->pseudo_merge)
                        BUG("found non-pseudo merge commit at %"PRIuMAX, (uintmax_t)i);
 
-               commits_bitmap[i] = bitmap_new();
-
                for (p = merge->commit->parents; p; p = p->next)
-                       bitmap_set(commits_bitmap[i],
+                       bitmap_set(parents,
                                   find_object_pos(writer, &p->item->object.oid,
                                                   NULL));
+
+               merge->pseudo_merge_parents = bitmap_to_ewah(parents);
+               bitmap_free(parents);
        }
 
        start = hashfile_total(f);
 
        for (i = 0; i < writer->pseudo_merges_nr; i++) {
-               struct ewah_bitmap *commits_ewah = bitmap_to_ewah(commits_bitmap[i]);
+               struct bitmapped_commit *merge = &writer->selected[base + i];
+
+               if (!merge->pseudo_merge)
+                       BUG("found non-pseudo merge commit at %"PRIuMAX, (uintmax_t)i);
+
+               if (!merge->pseudo_merge_parents)
+                       BUG("missing pseudo-merge parents bitmap for commit %s",
+                           oid_to_hex(&merge->commit->object.oid));
 
                pseudo_merge_ofs[i] = hashfile_total(f);
 
-               dump_bitmap(f, commits_ewah);
+               dump_bitmap(f, merge->pseudo_merge_parents);
                dump_bitmap(f, writer->selected[base+i].write_as);
-
-               ewah_free(commits_ewah);
        }
 
        next_ext = st_add(hashfile_total(f),
@@ -1122,12 +1130,8 @@ static void write_pseudo_merges(struct bitmap_writer *writer,
        hashwrite_be64(f, table_start - start);
        hashwrite_be64(f, hashfile_total(f) - start + sizeof(uint64_t));
 
-       for (i = 0; i < writer->pseudo_merges_nr; i++)
-               bitmap_free(commits_bitmap[i]);
-
        oid_array_clear(&commits);
        free(pseudo_merge_ofs);
-       free(commits_bitmap);
 }
 
 static int table_cmp(const void *_va, const void *_vb, void *_data)