@matheusbsbs / matheus-bagliano / commits / caca3c9f07

midx.c: respect 'pack.writeBitmapHashcache' when writing bitmaps

In the previous commit, the bitmap writing code learned to propagate values from an existing hash-cache extension into the bitmap that it is writing. Now that that functionality exists, let's expose it by teaching the 'git multi-pack-index' builtin to respect the `pack.writeBitmapHashCache` option so that the hash-cache may be written at all. Two minor points worth noting here: - The 'git multi-pack-index write' sub-command didn't previously read any configuration (instead this is handled in the base command). A separate handler is added here to respect this write-specific config option. - I briefly considered adding a 'bitmap_flags' field to the static options struct, but decided against it since it would require plumbing through a new parameter to the write_midx_file() function. Instead, a new MIDX-specific flag is added, which is translated to the corresponding bitmap one. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Taylor Blau committed Sep 14, 2021 at 18:06 UTC caca3c9f07f90645e32c284c88c379109abf59be

4 files changed +31 -1

Documentation/config/pack.txt

@@ -159,6 +159,10 @@ pack.writeBitmapHashCache::

159 between an older, bitmapped pack and objects that have been

160 pushed since the last gc). The downside is that it consumes 4

161 bytes per object of disk space. Defaults to true.

162 ++

163 +When writing a multi-pack reachability bitmap, no new namehashes are

164 +computed; instead, any namehashes stored in an existing bitmap are

165 +permuted into their appropriate location when writing a new bitmap.

166

167 pack.writeReverseIndex::

168 When true, git will write a corresponding .rev file (see:

builtin/multi-pack-index.c

+21

@@ -61,6 +61,23 @@ static struct option *add_common_options(struct option *prev)

61 return parse_options_concat(common_opts, prev);

62 }

64 +static int git_multi_pack_index_write_config(const char *var, const char *value,

65 + void *cb)

66 +{

67 + if (!strcmp(var, "pack.writebitmaphashcache")) {

68 + if (git_config_bool(var, value))

69 + opts.flags |= MIDX_WRITE_BITMAP_HASH_CACHE;

70 + else

71 + opts.flags &= ~MIDX_WRITE_BITMAP_HASH_CACHE;

72 + }

73 +

74 + /*

75 + * We should never make a fall-back call to 'git_default_config', since

76 + * this was already called in 'cmd_multi_pack_index()'.

77 + */

78 + return 0;

79 +}

80 +

81 static int cmd_multi_pack_index_write(int argc, const char **argv)

82 {

83 struct option *options;

@@ -73,6 +90,10 @@ static int cmd_multi_pack_index_write(int argc, const char **argv)

90 OPT_END(),

91 };

93 + opts.flags |= MIDX_WRITE_BITMAP_HASH_CACHE;

94 +

95 + git_config(git_multi_pack_index_write_config, NULL);

96 +

97 options = add_common_options(builtin_multi_pack_index_write_options);

99 trace2_cmd_mode(argv[0]);

midx.c

+5 -1

@@ -1008,9 +1008,13 @@ static int write_midx_bitmap(char *midx_name, unsigned char *midx_hash,

1008 struct pack_idx_entry **index;

1009 struct commit **commits = NULL;

1010 uint32_t i, commits_nr;

1011 + uint16_t options = 0;

1012 char *bitmap_name = xstrfmt("%s-%s.bitmap", midx_name, hash_to_hex(midx_hash));

1013 int ret;

1014

1015 + if (flags & MIDX_WRITE_BITMAP_HASH_CACHE)

1016 + options |= BITMAP_OPT_HASH_CACHE;

1017 +

1018 prepare_midx_packing_data(&pdata, ctx);

1019

1020 commits = find_commits_for_midx_bitmap(&commits_nr, ctx);

@@ -1049,7 +1053,7 @@ static int write_midx_bitmap(char *midx_name, unsigned char *midx_hash,

1053 goto cleanup;

1054

1055 bitmap_writer_set_checksum(midx_hash);

1052 - bitmap_writer_finish(index, pdata.nr_objects, bitmap_name, 0);

1056 + bitmap_writer_finish(index, pdata.nr_objects, bitmap_name, options);

1057

1058 cleanup:

1059 free(index);

midx.h

@@ -44,6 +44,7 @@ struct multi_pack_index {

44 #define MIDX_PROGRESS (1 << 0)

45 #define MIDX_WRITE_REV_INDEX (1 << 1)

46 #define MIDX_WRITE_BITMAP (1 << 2)

47 +#define MIDX_WRITE_BITMAP_HASH_CACHE (1 << 3)

49 const unsigned char *get_midx_checksum(struct multi_pack_index *m);

50 char *get_midx_filename(const char *object_dir);