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 committedSep 14, 2021 at 18:06 UTCcaca3c9f07f90645e32c284c88c379109abf59be
4 files changed+31-1
Documentation/config/pack.txt
+4
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:
builtin/multi-pack-index.c
+21
index 73c0113b48..578ffea6e8 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;+ }++ /*+ * We should never make a fall-back call 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]);