pack-bitmap.c: read pseudo-merge extension
Now that the scaffolding for reading the pseudo-merge extension has been laid, teach the pack-bitmap machinery to read the pseudo-merge extension when present. Note that pseudo-merges themselves are not yet used during traversal, this step will be taken by a future commit. In the meantime, read the table and initialize the pseudo_merge_map structure introduced by a previous commit. When the pseudo-merge extension is present, `load_bitmap_header()` performs basic sanity checks to make sure that the table is well-formed. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Taylor Blau committed
May 23, 2024 at 17:26 UTC
7c0fae88442824cfb4a3160d61a00c54287d56a7
1 file changed
+39
pack-bitmap.c
+39
@@ -20,6 +20,7 @@
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#include "list-objects-filter-options.h"
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#include "midx.h"
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#include "config.h"
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+#include "pseudo-merge.h"
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/*
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* An entry on the bitmap index, representing the bitmap for a given
@@ -86,6 +87,9 @@ struct bitmap_index {
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*/
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unsigned char *table_lookup;
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+ /* This contains the pseudo-merge cache within 'map' (if found). */
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+ struct pseudo_merge_map pseudo_merges;
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+
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/*
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* Extended index.
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*
@@ -205,6 +209,41 @@ static int load_bitmap_header(struct bitmap_index *index)
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index->table_lookup = (void *)(index_end - table_size);
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index_end -= table_size;
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}
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+
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+ if (flags & BITMAP_OPT_PSEUDO_MERGES) {
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+ unsigned char *pseudo_merge_ofs;
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+ size_t table_size;
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+ uint32_t i;
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+
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+ if (sizeof(table_size) > index_end - index->map - header_size)
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+ return error(_("corrupted bitmap index file (too short to fit pseudo-merge table header)"));
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+
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+ table_size = get_be64(index_end - 8);
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+ if (table_size > index_end - index->map - header_size)
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+ return error(_("corrupted bitmap index file (too short to fit pseudo-merge table)"));
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+
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+ if (git_env_bool("GIT_TEST_USE_PSEUDO_MERGES", 1)) {
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+ const unsigned char *ext = (index_end - table_size);
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+
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+ index->pseudo_merges.map = index->map;
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+ index->pseudo_merges.map_size = index->map_size;
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+ index->pseudo_merges.commits = ext + get_be64(index_end - 16);
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+ index->pseudo_merges.commits_nr = get_be32(index_end - 20);
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+ index->pseudo_merges.nr = get_be32(index_end - 24);
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+
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+ CALLOC_ARRAY(index->pseudo_merges.v,
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+ index->pseudo_merges.nr);
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+
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+ pseudo_merge_ofs = index_end - 24 -
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+ (index->pseudo_merges.nr * sizeof(uint64_t));
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+ for (i = 0; i < index->pseudo_merges.nr; i++) {
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+ index->pseudo_merges.v[i].at = get_be64(pseudo_merge_ofs);
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+ pseudo_merge_ofs += sizeof(uint64_t);
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+ }
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+ }
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+
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+ index_end -= table_size;
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+ }
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}
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index->entry_count = ntohl(header->entry_count);