Commentary: I included the pack directory of the MIDX file as a FLEX_ARRAY
at the end of the midxed_git struct, similar to how the pack name appears
at the end of the packed_git struct. A colleague mentioned this pattern is
confusing and possibly dangerous so I should consider changing it. If there
is no strong reason for this, then I will modify the struct before the v1
patch to use a char*.
-- >8 --
Add a "--read" subcommand to the midx builtin to report summary information
on the head MIDX file or a MIDX file specified by the supplied "--midx-id"
parameter.
This subcommand is used by t5318-midx.sh to verify the indexed objects are
as expected.
Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
---
Documentation/git-midx.txt | 23 +++++++-
builtin/midx.c | 59 ++++++++++++++++++++
midx.c | 132 +++++++++++++++++++++++++++++++++++++++++++++
midx.h | 58 ++++++++++++++++++++
t/t5318-midx.sh | 79 +++++++++++++++++++--------
5 files changed, 328 insertions(+), 23 deletions(-)
diff --git a/Documentation/git-midx.txt b/Documentation/git-midx.txt
index 01f79cbba5..3eeed1d969 100644
--- a/Documentation/git-midx.txt
+++ b/Documentation/git-midx.txt
@@ -9,7 +9,7 @@ git-midx - Write and verify multi-pack-indexes (MIDX files).
SYNOPSIS
--------
[verse]
-'git midx' --write <options> [--pack-dir <pack_dir>]
+'git midx' [--write|--read] <options> [--pack-dir <pack_dir>]
DESCRIPTION
-----------
@@ -22,9 +22,18 @@ OPTIONS
Use given directory for the location of packfiles, pack-indexes,
and MIDX files.
+--read::
+ If specified, read a midx file specified by the midx-head file
+ and output basic details about the midx file. (Cannot be combined
+ with --write.)
+
+--midx-id <oid>::
+ If specified with --read, use the given oid to read midx-[oid].midx
+ instead of using midx-head.
--write::
If specified, write a new midx file to the pack directory using
the packfiles present. Outputs the hash of the result midx file.
+ (Cannot be combined with --read.)
--update-head::
If specified with --write, update the midx-head file to point to
@@ -58,6 +67,18 @@ $ git midx --write --update-head
$ git midx --write --pack-dir ../../alt/pack/
---------------------------------------------------------
+* Read the current midx-head.
++
+-----------------------------------------------
+$ git midx --read
+-----------------------------------------------
+
+* Read a specific MIDX file in the local .git folder.
++
+--------------------------------------------------------------------
+$ git midx --read --midx-id 3e50d982a2257168c7fd0ff12ffe5cf6af38c74e
+--------------------------------------------------------------------
+
CONFIGURATION
-------------
diff --git a/builtin/midx.c b/builtin/midx.c
index 84ce6588a2..ee9234583d 100644
--- a/builtin/midx.c
+++ b/builtin/midx.c
@@ -16,12 +16,60 @@ static char const * const builtin_midx_usage[] = {
static struct opts_midx {
const char *pack_dir;
+ int read;
+ const char *midx_id;
int write;
int update_head;
int has_existing;
struct object_id old_midx_oid;
} opts;
+static int midx_read(void)
+{
+ struct object_id midx_oid;
+ struct midxed_git *midx;
+ uint32_t i;
+
+ if (opts.midx_id && strlen(opts.midx_id) == GIT_MAX_HEXSZ)
+ get_oid_hex(opts.midx_id, &midx_oid);
+ else if (!get_midx_head_oid(opts.pack_dir, &midx_oid))
+ die("No midx-head exists.");
+
+ midx = get_midxed_git(opts.pack_dir, &midx_oid);
+
+ printf("header: %08x %x %d %d %d %d %d\n",
+ ntohl(midx->hdr->midx_signature),
+ ntohl(midx->hdr->midx_version),
+ midx->hdr->hash_version,
+ midx->hdr->hash_len,
+ midx->hdr->num_base_midx,
+ midx->hdr->num_chunks,
+ ntohl(midx->hdr->num_packs));
+ printf("num_objects: %d\n", midx->num_objects);
+ printf("chunks:");
+
+ if (midx->chunk_pack_lookup)
+ printf(" pack_lookup");
+ if (midx->chunk_pack_names)
+ printf(" pack_names");
+ if (midx->chunk_oid_fanout)
+ printf(" oid_fanout");
+ if (midx->chunk_oid_lookup)
+ printf(" oid_lookup");
+ if (midx->chunk_object_offsets)
+ printf(" object_offsets");
+ if (midx->chunk_large_offsets)
+ printf(" large_offsets");
+ printf("\n");
+
+ printf("pack_names:\n");
+ for (i = 0; i < midx->num_packs; i++)
+ printf("%s\n", midx->pack_names[i]);
+
+ printf("pack_dir: %s\n", midx->pack_dir);
+ return 0;
+}
+
static int build_midx_from_packs(
const char *pack_dir,
const char **pack_names, uint32_t nr_packs,
@@ -187,6 +235,12 @@ int cmd_midx(int argc, const char **argv, const char
*prefix)
{ OPTION_STRING, 'p', "pack-dir", &opts.pack_dir,
N_("dir"),
N_("The pack directory containing set of packfile and
pack-index pairs.") },
+ OPT_BOOL('r', "read", &opts.read,
+ N_("read midx file")),
+ { OPTION_STRING, 'M', "midx-id", &opts.midx_id,
+ N_("oid"),
+ N_("An OID for a specific midx file in the pack-dir."),
+ PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
OPT_BOOL('w', "write", &opts.write,
N_("write midx file")),
OPT_BOOL('u', "update-head", &opts.update_head,
@@ -205,6 +259,9 @@ int cmd_midx(int argc, const char **argv, const char
*prefix)
builtin_midx_options,
builtin_midx_usage, 0);
+ if (opts.write + opts.read > 1)
+ usage_with_options(builtin_midx_usage, builtin_midx_options);
+
if (!opts.pack_dir) {
struct strbuf path = STRBUF_INIT;
strbuf_addstr(&path, get_object_directory());
@@ -214,6 +271,8 @@ int cmd_midx(int argc, const char **argv, const char
*prefix)
opts.has_existing = !!get_midx_head_oid(opts.pack_dir,
&opts.old_midx_oid);
+ if (opts.read)
+ return midx_read();
if (opts.write)
return midx_write();
diff --git a/midx.c b/midx.c
index f4178c1b81..c631be451f 100644
--- a/midx.c
+++ b/midx.c
@@ -65,6 +65,138 @@ struct object_id *get_midx_head_oid(const char *pack_dir,
return oid;
}
+static struct midxed_git *alloc_midxed_git(int extra)
+{
+ struct midxed_git *m = xmalloc(st_add(sizeof(*m), extra));
+ memset(m, 0, sizeof(*m));
+ m->midx_fd = -1;
+
+ return m;
+}
+
+static struct midxed_git *load_midxed_git_one(const char *midx_file, const
char *pack_dir)
+{
+ void *midx_map;
+ const unsigned char *data;
+ struct pack_midx_header *hdr;
+ size_t midx_size, packs_len;
+ struct stat st;
+ uint32_t i;
+ struct midxed_git *midx;
+ int fd = git_open(midx_file);
+
+ if (fd < 0)
+ return 0;
+ if (fstat(fd, &st)) {
+ close(fd);
+ return 0;
+ }
+ midx_size = xsize_t(st.st_size);
+
+ if (midx_size < 16 + 8 * 5 + 4 * 256 + GIT_MAX_RAWSZ) {
+ close(fd);
+ die("midx file %s is too small", midx_file);
+ }
+ midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
+ data = (const unsigned char *)midx_map;
+
+ hdr = midx_map;
+ if (ntohl(hdr->midx_signature) != MIDX_SIGNATURE) {
+ munmap(midx_map, midx_size);
+ close(fd);
+ die("MIDX signature %X does not match signature %X",
+ ntohl(hdr->midx_signature), MIDX_SIGNATURE);
+ }
+
+ if (ntohl(hdr->midx_version) != MIDX_VERSION) {
+ munmap(midx_map, midx_size);
+ die("MIDX version %X does not match version %X",
+ ntohl(hdr->midx_version), MIDX_VERSION);
+ }
+
+ midx = alloc_midxed_git(strlen(pack_dir) + 1);
+
+ midx->hdr = hdr;
+ midx->midx_fd = fd;
+ midx->data = midx_map;
+ midx->data_len = midx_size;
+
+ for (i = 0; i <= hdr->num_chunks; i++) {
+ uint32_t chunk_id = ntohl(*(uint32_t*)(data + sizeof(*hdr) + 12
* i));
+ uint64_t chunk_offset1 = ntohl(*(uint32_t*)(data + sizeof(*hdr)
+ 12 * i + 4));
+ uint32_t chunk_offset2 = ntohl(*(uint32_t*)(data + sizeof(*hdr)
+ 12 * i + 8));
+ uint64_t chunk_offset = (chunk_offset1 << 32) | chunk_offset2;
+
+ if (sizeof(data) == 4 && chunk_offset >> 32) {
+ munmap(midx_map, midx_size);
+ close(fd);
+ die(_("unable to memory-map in 32-bit address space"));
+ }
+
+ switch (chunk_id) {
+ case MIDX_CHUNKID_PACKLOOKUP:
+ midx->chunk_pack_lookup = data + chunk_offset;
+ break;
+
+ case MIDX_CHUNKID_PACKNAMES:
+ midx->chunk_pack_names = data + chunk_offset;
+ break;
+
+ case MIDX_CHUNKID_OIDFANOUT:
+ midx->chunk_oid_fanout = data + chunk_offset;
+ break;
+
+ case MIDX_CHUNKID_OIDLOOKUP:
+ midx->chunk_oid_lookup = data + chunk_offset;
+ break;
+
+ case MIDX_CHUNKID_OBJECTOFFSETS:
+ midx->chunk_object_offsets = data +
chunk_offset;
+ break;
+
+ case MIDX_CHUNKID_LARGEOFFSETS:
+ midx->chunk_large_offsets = data + chunk_offset;
+ break;
+
+ case 0:
+ break;
+
+ default:
+ munmap(midx_map, midx_size);
+ close(fd);
+ die("unrecognized MIDX chunk id: %08x",
chunk_id);
+ }
+ }
+
+ midx->num_objects = ntohl(*((uint32_t*)(midx->chunk_oid_fanout + 255 *
4)));
+ midx->num_packs = ntohl(midx->hdr->num_packs);
+
+ packs_len = st_mult(sizeof(struct packed_git*), midx->num_packs);
+
+ if (packs_len) {
+ ALLOC_ARRAY(midx->packs, midx->num_packs);
+ ALLOC_ARRAY(midx->pack_names, midx->num_packs);
+ memset(midx->packs, 0, packs_len);
+
+ for (i = 0; i < midx->num_packs; i++) {
+ uint32_t name_offset =
ntohl(*(uint32_t*)(midx->chunk_pack_lookup + 4 * i));
+ midx->pack_names[i] = (const
char*)(midx->chunk_pack_names + name_offset);
+ }
+ }
+
+ strcpy(midx->pack_dir, pack_dir);
+ return midx;
+}
+
+struct midxed_git *get_midxed_git(const char *pack_dir, struct object_id *oid)
+{
+ struct midxed_git *m;
+ char *fname = get_midx_filename_oid(pack_dir, oid);
+ m = load_midxed_git_one(fname, pack_dir);
+ free(fname);
+ return m;
+}
+
struct pack_midx_details_internal {
uint32_t pack_int_id;
uint32_t internal_offset;
diff --git a/midx.h b/midx.h
index 9d9ab85261..92b74e49db 100644
--- a/midx.h
+++ b/midx.h
@@ -27,6 +27,64 @@ struct pack_midx_header {
uint32_t num_packs;
};
+struct midxed_git {
+ struct midxed_git *next;
+
+ int midx_fd;
+
+ /* the mmap'd data for the midx file */
+ const unsigned char *data;
+ size_t data_len;
+
+ /* points into the mmap'd data */
+ struct pack_midx_header *hdr;
+
+ /* can construct filename from obj_dir + "/packs/midx-" + oid + ".midx"
*/
+ struct object_id oid;
+
+ /* derived from the fanout chunk */
+ uint32_t num_objects;
+
+ /* converted number of packs */
+ uint32_t num_packs;
+
+ /* hdr->num_packs * 4 bytes */
+ const unsigned char *chunk_pack_lookup;
+ const unsigned char *chunk_pack_names;
+
+ /* 256 * 4 bytes */
+ const unsigned char *chunk_oid_fanout;
+
+ /* num_objects * hdr->hash_len bytes */
+ const unsigned char *chunk_oid_lookup;
+
+ /* num_objects * 8 bytes */
+ const unsigned char *chunk_object_offsets;
+
+ /*
+ * 8 bytes per large offset.
+ * (Optional: may be null.)
+ */
+ const unsigned char *chunk_large_offsets;
+
+ /*
+ * Points into mmap'd data storing the pack filenames.
+ */
+ const char **pack_names;
+
+ /*
+ * Store an array of pack-pointers. If NULL, then the
+ * pack has not been loaded yet. The array indices
+ * correspond to the pack_int_ids from the midx storage.
+ */
+ struct packed_git **packs;
+
+ /* something like ".git/objects/pack" */
+ char pack_dir[FLEX_ARRAY]; /* more */
+};
+
+extern struct midxed_git *get_midxed_git(const char *pack_dir, struct
object_id *oid);
+
/*
* Write a single MIDX file storing the given entries for the
* given list of packfiles. If midx_name is null, then a temp
diff --git a/t/t5318-midx.sh b/t/t5318-midx.sh
index b66efcdce9..2e52389442 100755
--- a/t/t5318-midx.sh
+++ b/t/t5318-midx.sh
@@ -26,11 +26,27 @@ test_expect_success 'create objects' \
git commit -m "test data 1" &&
git branch commit1 HEAD'
+_midx_read_expect() {
+ cat >expect <<- EOF
+ header: 4d494458 1 1 20 0 5 $1
+ num_objects: $2
+ chunks: pack_lookup pack_names oid_fanout oid_lookup object_offsets
+ pack_names:
+ $(ls $3 | grep pack | grep -v idx | sort)
+ pack_dir: $3
+ EOF
+}
+
test_expect_success 'write-midx from index version 1' \
'pack1=$(git rev-list --all --objects | git pack-objects --index-version=1
${packdir}/test-1) &&
midx1=$(git midx --write) &&
test_path_is_file ${packdir}/midx-${midx1}.midx &&
- test_path_is_missing ${packdir}/midx-head'
+ test_path_is_missing ${packdir}/midx-head &&
+ _midx_read_expect \
+ "1" "102" \
+ "${packdir}" &&
+ git midx --read --midx-id=${midx1} >output &&
+ cmp output expect'
test_expect_success 'write-midx from index version 2' \
'rm "${packdir}/test-1-${pack1}.pack" &&
@@ -38,12 +54,17 @@ test_expect_success 'write-midx from index version 2' \
midx2=$(git midx --write --update-head) &&
test_path_is_file ${packdir}/midx-${midx2}.midx &&
test_path_is_file ${packdir}/midx-head &&
- test $(cat ${packdir}/midx-head) = "$midx2"'
+ test $(cat ${packdir}/midx-head) = "$midx2" &&
+ _midx_read_expect \
+ "1" "102" \
+ "${packdir}" &&
+ git midx --read> output &&
+ cmp output expect'
test_expect_success 'Create more objects' \
'for i in $(test_seq 100)
do
- echo $i >file-2-$i
+ echo extra-$i >file-2-$i
done &&
git add file-* &&
test_tick &&
@@ -55,28 +76,32 @@ test_expect_success 'write-midx with two packs' \
midx3=$(git midx --write --update-head) &&
test_path_is_file ${packdir}/midx-${midx3}.midx &&
test_path_is_file ${packdir}/midx-head &&
- test $(cat ${packdir}/midx-head) = "$midx3"'
+ test $(cat ${packdir}/midx-head) = "$midx3" &&
+ _midx_read_expect \
+ "2" "204" \
+ "${packdir}" &&
+ git midx --read >output &&
+ cmp output expect'
test_expect_success 'Add more packs' \
- 'for j in $(test_seq 10)
+ 'for i in $(test_seq 10)
do
- jjj=$(printf '%03i' $j)
- test-genrandom "bar" 200 > wide_delta_$jjj &&
- test-genrandom "baz $jjj" 50 >> wide_delta_$jjj &&
- test-genrandom "foo"$j 100 > deep_delta_$jjj &&
- test-genrandom "foo"$(expr $j + 1) 100 >> deep_delta_$jjj &&
- test-genrandom "foo"$(expr $j + 2) 100 >> deep_delta_$jjj &&
- echo $jjj >file_$jjj &&
- test-genrandom "$jjj" 8192 >>file_$jjj &&
- git update-index --add file_$jjj deep_delta_$jjj wide_delta_$jjj &&
+ iii=$(printf '%03i' $i)
+ test-genrandom "bar" 200 > wide_delta_$iii &&
+ test-genrandom "baz $iii" 50 >> wide_delta_$iii &&
+ test-genrandom "foo"$i 100 > deep_delta_$iii &&
+ test-genrandom "foo"$(expr $i + 1) 100 >> deep_delta_$iii &&
+ test-genrandom "foo"$(expr $i + 2) 100 >> deep_delta_$iii &&
+ echo $iii >file_$iii &&
+ test-genrandom "$iii" 8192 >>file_$iii &&
+ git update-index --add file_$iii deep_delta_$iii wide_delta_$iii &&
{ echo 101 && test-genrandom 100 8192; } >file_101 &&
git update-index --add file_101 &&
- commit=$(git commit-tree $EMPTY_TREE -p HEAD</dev/null) && {
- echo $EMPTY_TREE &&
- git ls-tree $EMPTY_TREE | sed -e "s/.* \\([0-9a-f]*\\) .*/\\1/"
+ tree=$(git write-tree) &&
+ commit=$(git commit-tree $tree -p HEAD</dev/null) && {
+ echo $tree &&
+ git ls-tree $tree | sed -e "s/.* \\([0-9a-f]*\\) .*/\\1/"
} >obj-list &&
- echo commit_packs_$j = $commit &&
- git branch commit_packs_$j $commit &&
git update-ref HEAD $commit &&
git pack-objects --index-version=2 ${packdir}/test-pack <obj-list
done'
@@ -85,7 +110,12 @@ test_expect_success 'write-midx with twelve packs' \
'midx4=$(git midx --write --update-head) &&
test_path_is_file ${packdir}/midx-${midx4}.midx &&
test_path_is_file ${packdir}/midx-head &&
- test $(cat ${packdir}/midx-head) = "$midx4"'
+ test $(cat ${packdir}/midx-head) = "$midx4" &&
+ _midx_read_expect \
+ "12" "245" \
+ "${packdir}" &&
+ git midx --read >output &&
+ cmp output expect'
test_expect_success 'write-midx with no new packs' \
'midx5=$(git midx --write --update-head) &&
@@ -100,12 +130,17 @@ test_expect_success 'create bare repo' \
cd bare &&
git config core.midx true &&
git config pack.threads 1 &&
- baredir=objects/pack'
+ baredir=./objects/pack'
test_expect_success 'write-midx in bare repo' \
'midxbare=$(git midx --write --update-head) &&
test_path_is_file ${baredir}/midx-${midxbare}.midx &&
test_path_is_file ${baredir}/midx-head &&
- test $(cat ${baredir}/midx-head) = "$midxbare"'
+ test $(cat ${baredir}/midx-head) = "$midxbare" &&
+ _midx_read_expect \
+ "12" "245" \
+ "${baredir}" &&
+ git midx --read >output &&
+ cmp output expect'
test_done
--
2.15.0
