config: create core.multiPackIndex setting

The core.multiPackIndex config setting controls the multi-pack-
index (MIDX) feature. If false, the setting will disable all reads
from the multi-pack-index file.

Read this config setting in the new prepare_multi_pack_index_one()
which is called during prepare_packed_git(). This check is run once
per repository.

Add comparison commands in t5319-multi-pack-index.sh to check
typical Git behavior remains the same as the config setting is turned
on and off. This currently includes 'git rev-list' and 'git log'
commands to trigger several object database reads. Currently, these
would only catch an error in the prepare_multi_pack_index_one(), but
with later commits will catch errors in object lookups, abbreviations,
and approximate object counts.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Derrick Stolee 2018-07-12 15:39:33 -04:00 коммит произвёл Junio C Hamano
Родитель 662148c435
Коммит c4d25228eb
6 изменённых файлов: 85 добавлений и 14 удалений

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@ -908,6 +908,11 @@ core.commitGraph::
Enable git commit graph feature. Allows reading from the
commit-graph file.
core.multiPackIndex::
Use the multi-pack-index file to track multiple packfiles using a
single index. See link:technical/multi-pack-index.html[the
multi-pack-index design document].
core.sparseCheckout::
Enable "sparse checkout" feature. See section "Sparse checkout" in
linkgit:git-read-tree[1] for more information.

25
midx.c
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@ -1,4 +1,5 @@
#include "cache.h"
#include "config.h"
#include "csum-file.h"
#include "dir.h"
#include "lockfile.h"
@ -177,6 +178,30 @@ cleanup_fail:
return NULL;
}
int prepare_multi_pack_index_one(struct repository *r, const char *object_dir)
{
struct multi_pack_index *m = r->objects->multi_pack_index;
struct multi_pack_index *m_search;
int config_value;
if (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
!config_value)
return 0;
for (m_search = m; m_search; m_search = m_search->next)
if (!strcmp(object_dir, m_search->object_dir))
return 1;
r->objects->multi_pack_index = load_multi_pack_index(object_dir);
if (r->objects->multi_pack_index) {
r->objects->multi_pack_index->next = m;
return 1;
}
return 0;
}
static size_t write_midx_header(struct hashfile *f,
unsigned char num_chunks,
uint32_t num_packs)

5
midx.h
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@ -1,7 +1,11 @@
#ifndef __MIDX_H__
#define __MIDX_H__
#include "repository.h"
struct multi_pack_index {
struct multi_pack_index *next;
int fd;
const unsigned char *data;
@ -25,6 +29,7 @@ struct multi_pack_index {
};
struct multi_pack_index *load_multi_pack_index(const char *object_dir);
int prepare_multi_pack_index_one(struct repository *r, const char *object_dir);
int write_midx_file(const char *object_dir);

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@ -105,6 +105,13 @@ struct raw_object_store {
*/
struct oidmap *replace_map;
/*
* private data
*
* should only be accessed directly by packfile.c and midx.c
*/
struct multi_pack_index *multi_pack_index;
/*
* private data
*

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@ -15,6 +15,7 @@
#include "tree-walk.h"
#include "tree.h"
#include "object-store.h"
#include "midx.h"
char *odb_pack_name(struct strbuf *buf,
const unsigned char *sha1,
@ -935,10 +936,13 @@ static void prepare_packed_git(struct repository *r)
if (r->objects->packed_git_initialized)
return;
prepare_multi_pack_index_one(r, r->objects->objectdir);
prepare_packed_git_one(r, r->objects->objectdir, 1);
prepare_alt_odb(r);
for (alt = r->objects->alt_odb_list; alt; alt = alt->next)
for (alt = r->objects->alt_odb_list; alt; alt = alt->next) {
prepare_multi_pack_index_one(r, alt->path);
prepare_packed_git_one(r, alt->path, 0);
}
rearrange_packed_git(r);
prepare_packed_git_mru(r);
r->objects->packed_git_initialized = 1;

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@ -3,6 +3,8 @@
test_description='multi-pack-indexes'
. ./test-lib.sh
objdir=.git/objects
midx_read_expect () {
NUM_PACKS=$1
NUM_OBJECTS=$2
@ -76,18 +78,35 @@ test_expect_success 'create objects' '
'
test_expect_success 'write midx with one v1 pack' '
pack=$(git pack-objects --index-version=1 pack/test <obj-list) &&
test_when_finished rm pack/test-$pack.pack pack/test-$pack.idx pack/multi-pack-index &&
git multi-pack-index --object-dir=. write &&
midx_read_expect 1 18 4 .
pack=$(git pack-objects --index-version=1 $objdir/pack/test <obj-list) &&
test_when_finished rm $objdir/pack/test-$pack.pack \
$objdir/pack/test-$pack.idx $objdir/pack/multi-pack-index &&
git multi-pack-index --object-dir=$objdir write &&
midx_read_expect 1 18 4 $objdir
'
midx_git_two_modes () {
git -c core.multiPackIndex=false $1 >expect &&
git -c core.multiPackIndex=true $1 >actual &&
test_cmp expect actual
}
compare_results_with_midx () {
MSG=$1
test_expect_success "check normal git operations: $MSG" '
midx_git_two_modes "rev-list --objects --all" &&
midx_git_two_modes "log --raw"
'
}
test_expect_success 'write midx with one v2 pack' '
git pack-objects --index-version=2,0x40 pack/test <obj-list &&
git multi-pack-index --object-dir=. write &&
midx_read_expect 1 18 4 .
git pack-objects --index-version=2,0x40 $objdir/pack/test <obj-list &&
git multi-pack-index --object-dir=$objdir write &&
midx_read_expect 1 18 4 $objdir
'
compare_results_with_midx "one v2 pack"
test_expect_success 'add more objects' '
for i in $(test_seq 6 10)
do
@ -97,25 +116,31 @@ test_expect_success 'add more objects' '
'
test_expect_success 'write midx with two packs' '
git pack-objects --index-version=1 pack/test-2 <obj-list &&
git multi-pack-index --object-dir=. write &&
midx_read_expect 2 34 4 .
git pack-objects --index-version=1 $objdir/pack/test-2 <obj-list &&
git multi-pack-index --object-dir=$objdir write &&
midx_read_expect 2 34 4 $objdir
'
compare_results_with_midx "two packs"
test_expect_success 'add more packs' '
for j in $(test_seq 11 20)
do
generate_objects $j &&
commit_and_list_objects &&
git pack-objects --index-version=2 pack/test-pack <obj-list
git pack-objects --index-version=2 $objdir/pack/test-pack <obj-list
done
'
compare_results_with_midx "mixed mode (two packs + extra)"
test_expect_success 'write midx with twelve packs' '
git multi-pack-index --object-dir=. write &&
midx_read_expect 12 74 4 .
git multi-pack-index --object-dir=$objdir write &&
midx_read_expect 12 74 4 $objdir
'
compare_results_with_midx "twelve packs"
# usage: corrupt_data <file> <pos> [<data>]
corrupt_data () {
file=$1