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@xxxxxxxxxxxx>
---
Documentation/config/pack.txt | 4 ++++
builtin/multi-pack-index.c | 21 +++++++++++++++++++++
midx.c | 6 +++++-
midx.h | 1 +
4 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/Documentation/config/pack.txt b/Documentation/config/pack.txt
index 763f7af7c4..ad7f73a1ea 100644
--- a/Documentation/config/pack.txt
+++ b/Documentation/config/pack.txt
@@ -159,6 +159,10 @@ pack.writeBitmapHashCache::
between an older, bitmapped pack and objects that have been
pushed since the last gc). The downside is that it consumes 4
bytes per object of disk space. Defaults to true.
++
+When writing a multi-pack reachability bitmap, no new namehashes are
+computed; instead, any namehashes stored in an existing bitmap are
+permuted into their appropriate location when writing a new bitmap.
pack.writeReverseIndex::
When true, git will write a corresponding .rev file (see:
diff --git a/builtin/multi-pack-index.c b/builtin/multi-pack-index.c
index 73c0113b48..dd1652531b 100644
--- a/builtin/multi-pack-index.c
+++ b/builtin/multi-pack-index.c
@@ -61,6 +61,23 @@ static struct option *add_common_options(struct option *prev)
return parse_options_concat(common_opts, prev);
}
+static int git_multi_pack_index_write_config(const char *var, const char *value,
+ void *cb)
+{
+ if (!strcmp(var, "pack.writebitmaphashcache")) {
+ if (git_config_bool(var, value))
+ opts.flags |= MIDX_WRITE_BITMAP_HASH_CACHE;
+ else
+ opts.flags &= ~MIDX_WRITE_BITMAP_HASH_CACHE;
+ }
+
+ /*
+ * No need to fall-back to 'git_default_config', since this was already
+ * called in 'cmd_multi_pack_index()'.
+ */
+ return 0;
+}
+
static int cmd_multi_pack_index_write(int argc, const char **argv)
{
struct option *options;
@@ -73,6 +90,10 @@ static int cmd_multi_pack_index_write(int argc, const char **argv)
OPT_END(),
};
+ opts.flags |= MIDX_WRITE_BITMAP_HASH_CACHE;
+
+ git_config(git_multi_pack_index_write_config, NULL);
+
options = add_common_options(builtin_multi_pack_index_write_options);
trace2_cmd_mode(argv[0]);
diff --git a/midx.c b/midx.c
index ccdc3e5702..6c35dcd557 100644
--- a/midx.c
+++ b/midx.c
@@ -1008,9 +1008,13 @@ static int write_midx_bitmap(char *midx_name, unsigned char *midx_hash,
struct pack_idx_entry **index;
struct commit **commits = NULL;
uint32_t i, commits_nr;
+ uint16_t options = 0;
char *bitmap_name = xstrfmt("%s-%s.bitmap", midx_name, hash_to_hex(midx_hash));
int ret;
+ if (flags & MIDX_WRITE_BITMAP_HASH_CACHE)
+ options |= BITMAP_OPT_HASH_CACHE;
+
prepare_midx_packing_data(&pdata, ctx);
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,
goto cleanup;
bitmap_writer_set_checksum(midx_hash);
- bitmap_writer_finish(index, pdata.nr_objects, bitmap_name, 0);
+ bitmap_writer_finish(index, pdata.nr_objects, bitmap_name, options);
cleanup:
free(index);
diff --git a/midx.h b/midx.h
index aa3da557bb..541d9ac728 100644
--- a/midx.h
+++ b/midx.h
@@ -44,6 +44,7 @@ struct multi_pack_index {
#define MIDX_PROGRESS (1 << 0)
#define MIDX_WRITE_REV_INDEX (1 << 1)
#define MIDX_WRITE_BITMAP (1 << 2)
+#define MIDX_WRITE_BITMAP_HASH_CACHE (1 << 3)
const unsigned char *get_midx_checksum(struct multi_pack_index *m);
char *get_midx_filename(const char *object_dir);
--
2.33.0.96.g73915697e6
