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multi-pack-index: load into memory

Create a new multi_pack_index struct for loading multi-pack-indexes into
memory. Create a test-tool builtin for reading basic information about
that multi-pack-index to verify the correct data is written.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
maint
Derrick Stolee 7 years ago committed by Junio C Hamano
parent
commit
4d80560c54
  1. 1
      Makefile
  2. 79
      midx.c
  3. 18
      midx.h
  4. 2
      object-store.h
  5. 31
      t/helper/test-read-midx.c
  6. 1
      t/helper/test-tool.c
  7. 1
      t/helper/test-tool.h
  8. 11
      t/t5319-multi-pack-index.sh

1
Makefile

@ -717,6 +717,7 @@ TEST_BUILTINS_OBJS += test-online-cpus.o @@ -717,6 +717,7 @@ TEST_BUILTINS_OBJS += test-online-cpus.o
TEST_BUILTINS_OBJS += test-path-utils.o
TEST_BUILTINS_OBJS += test-prio-queue.o
TEST_BUILTINS_OBJS += test-read-cache.o
TEST_BUILTINS_OBJS += test-read-midx.o
TEST_BUILTINS_OBJS += test-ref-store.o
TEST_BUILTINS_OBJS += test-regex.o
TEST_BUILTINS_OBJS += test-revision-walking.o

79
midx.c

@ -1,18 +1,97 @@ @@ -1,18 +1,97 @@
#include "cache.h"
#include "csum-file.h"
#include "lockfile.h"
#include "object-store.h"
#include "midx.h"

#define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
#define MIDX_VERSION 1
#define MIDX_BYTE_FILE_VERSION 4
#define MIDX_BYTE_HASH_VERSION 5
#define MIDX_BYTE_NUM_CHUNKS 6
#define MIDX_BYTE_NUM_PACKS 8
#define MIDX_HASH_VERSION 1
#define MIDX_HEADER_SIZE 12
#define MIDX_HASH_LEN 20
#define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN)

static char *get_midx_filename(const char *object_dir)
{
return xstrfmt("%s/pack/multi-pack-index", object_dir);
}

struct multi_pack_index *load_multi_pack_index(const char *object_dir)
{
struct multi_pack_index *m = NULL;
int fd;
struct stat st;
size_t midx_size;
void *midx_map = NULL;
uint32_t hash_version;
char *midx_name = get_midx_filename(object_dir);

fd = git_open(midx_name);

if (fd < 0)
goto cleanup_fail;
if (fstat(fd, &st)) {
error_errno(_("failed to read %s"), midx_name);
goto cleanup_fail;
}

midx_size = xsize_t(st.st_size);

if (midx_size < MIDX_MIN_SIZE) {
error(_("multi-pack-index file %s is too small"), midx_name);
goto cleanup_fail;
}

FREE_AND_NULL(midx_name);

midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);

FLEX_ALLOC_MEM(m, object_dir, object_dir, strlen(object_dir));
m->fd = fd;
m->data = midx_map;
m->data_len = midx_size;

m->signature = get_be32(m->data);
if (m->signature != MIDX_SIGNATURE) {
error(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
m->signature, MIDX_SIGNATURE);
goto cleanup_fail;
}

m->version = m->data[MIDX_BYTE_FILE_VERSION];
if (m->version != MIDX_VERSION) {
error(_("multi-pack-index version %d not recognized"),
m->version);
goto cleanup_fail;
}

hash_version = m->data[MIDX_BYTE_HASH_VERSION];
if (hash_version != MIDX_HASH_VERSION) {
error(_("hash version %u does not match"), hash_version);
goto cleanup_fail;
}
m->hash_len = MIDX_HASH_LEN;

m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];

m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);

return m;

cleanup_fail:
free(m);
free(midx_name);
if (midx_map)
munmap(midx_map, midx_size);
if (0 <= fd)
close(fd);
return NULL;
}

static size_t write_midx_header(struct hashfile *f,
unsigned char num_chunks,
uint32_t num_packs)

18
midx.h

@ -1,6 +1,24 @@ @@ -1,6 +1,24 @@
#ifndef __MIDX_H__
#define __MIDX_H__

struct multi_pack_index {
int fd;

const unsigned char *data;
size_t data_len;

uint32_t signature;
unsigned char version;
unsigned char hash_len;
unsigned char num_chunks;
uint32_t num_packs;
uint32_t num_objects;

char object_dir[FLEX_ARRAY];
};

struct multi_pack_index *load_multi_pack_index(const char *object_dir);

int write_midx_file(const char *object_dir);

#endif

2
object-store.h

@ -84,6 +84,8 @@ struct packed_git { @@ -84,6 +84,8 @@ struct packed_git {
char pack_name[FLEX_ARRAY]; /* more */
};

struct multi_pack_index;

struct raw_object_store {
/*
* Path to the repository's object store.

31
t/helper/test-read-midx.c

@ -0,0 +1,31 @@ @@ -0,0 +1,31 @@
#include "test-tool.h"
#include "cache.h"
#include "midx.h"
#include "repository.h"
#include "object-store.h"

static int read_midx_file(const char *object_dir)
{
struct multi_pack_index *m = load_multi_pack_index(object_dir);

if (!m)
return 1;

printf("header: %08x %d %d %d\n",
m->signature,
m->version,
m->num_chunks,
m->num_packs);

printf("object-dir: %s\n", m->object_dir);

return 0;
}

int cmd__read_midx(int argc, const char **argv)
{
if (argc != 2)
usage("read-midx <object-dir>");

return read_midx_file(argv[1]);
}

1
t/helper/test-tool.c

@ -27,6 +27,7 @@ static struct test_cmd cmds[] = { @@ -27,6 +27,7 @@ static struct test_cmd cmds[] = {
{ "path-utils", cmd__path_utils },
{ "prio-queue", cmd__prio_queue },
{ "read-cache", cmd__read_cache },
{ "read-midx", cmd__read_midx },
{ "ref-store", cmd__ref_store },
{ "regex", cmd__regex },
{ "revision-walking", cmd__revision_walking },

1
t/helper/test-tool.h

@ -21,6 +21,7 @@ int cmd__online_cpus(int argc, const char **argv); @@ -21,6 +21,7 @@ int cmd__online_cpus(int argc, const char **argv);
int cmd__path_utils(int argc, const char **argv);
int cmd__prio_queue(int argc, const char **argv);
int cmd__read_cache(int argc, const char **argv);
int cmd__read_midx(int argc, const char **argv);
int cmd__ref_store(int argc, const char **argv);
int cmd__regex(int argc, const char **argv);
int cmd__revision_walking(int argc, const char **argv);

11
t/t5319-multi-pack-index.sh

@ -3,10 +3,19 @@ @@ -3,10 +3,19 @@
test_description='multi-pack-indexes'
. ./test-lib.sh

midx_read_expect () {
cat >expect <<-EOF
header: 4d494458 1 0 0
object-dir: .
EOF
test-tool read-midx . >actual &&
test_cmp expect actual
}

test_expect_success 'write midx with no packs' '
test_when_finished rm -f pack/multi-pack-index &&
git multi-pack-index --object-dir=. write &&
test_path_is_file pack/multi-pack-index
midx_read_expect
'

test_done

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