As we build the multi-pack-index feature by adding chunks at a time,
we want to test that the data is being written correctly.
Create struct midxed_git to store an in-memory representation of a
multi-pack-index and a memory-map of the binary file. Initialize this
struct in load_midxed_git(object_dir).
Create the 'git midx read' subcommand to output basic information about
the multi-pack-index file. This will be expanded as more information is
written to the file.
Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
---
Documentation/git-midx.txt | 11 +++++++
builtin/midx.c | 23 +++++++++++++-
midx.c | 65 ++++++++++++++++++++++++++++++++++++++
midx.h | 9 ++++++
object-store.h | 19 +++++++++++
t/t5319-midx.sh | 12 ++++++-
6 files changed, 137 insertions(+), 2 deletions(-)
diff --git a/Documentation/git-midx.txt b/Documentation/git-midx.txt
index dcaeb1a91b..919283fdd8 100644
--- a/Documentation/git-midx.txt
+++ b/Documentation/git-midx.txt
@@ -23,6 +23,11 @@ OPTIONS
<dir>/packs/multi-pack-index for the current MIDX file, and
<dir>/packs for the pack-files to index.
+read::
+ When given as the verb, read the current MIDX file and output
+ basic information about its contents. Used for debugging
+ purposes only.
+
write::
When given as the verb, write a new MIDX file to
<dir>/packs/multi-pack-index.
@@ -43,6 +48,12 @@ $ git midx write
$ git midx --object-dir <alt> write
-------------------------------------------
+* Read the MIDX file in the .git/objects folder.
++
+-------------------------------------------
+$ git midx read
+-------------------------------------------
+
GIT
---
diff --git a/builtin/midx.c b/builtin/midx.c
index dc0a5acd3f..c7002f664a 100644
--- a/builtin/midx.c
+++ b/builtin/midx.c
@@ -6,7 +6,7 @@
#include "midx.h"
static char const * const builtin_midx_usage[] ={
- N_("git midx [--object-dir <dir>] [write]"),
+ N_("git midx [--object-dir <dir>] [read|write]"),
NULL
};
@@ -14,6 +14,25 @@ static struct opts_midx {
const char *object_dir;
} opts;
+static int read_midx_file(const char *object_dir)
+{
+ struct midxed_git *m = load_midxed_git(object_dir);
+
+ if (!m)
+ return 0;
+
+ printf("header: %08x %d %d %d %d\n",
+ m->signature,
+ m->version,
+ m->hash_version,
+ m->num_chunks,
+ m->num_packs);
+
+ printf("object_dir: %s\n", m->object_dir);
+
+ return 0;
+}
+
int cmd_midx(int argc, const char **argv, const char *prefix)
{
static struct option builtin_midx_options[] = {
@@ -38,6 +57,8 @@ int cmd_midx(int argc, const char **argv, const char *prefix)
if (argc == 0)
return 0;
+ if (!strcmp(argv[0], "read"))
+ return read_midx_file(opts.object_dir);
if (!strcmp(argv[0], "write"))
return write_midx_file(opts.object_dir);
diff --git a/midx.c b/midx.c
index 3e55422a21..fa18770f1d 100644
--- a/midx.c
+++ b/midx.c
@@ -3,12 +3,15 @@
#include "dir.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_HASH_VERSION 1 /* SHA-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)
{
@@ -18,6 +21,68 @@ static char *get_midx_filename(const char *object_dir)
return strbuf_detach(&midx_name, NULL);
}
+struct midxed_git *load_midxed_git(const char *object_dir)
+{
+ struct midxed_git *m;
+ int fd;
+ struct stat st;
+ size_t midx_size;
+ void *midx_map;
+ const char *midx_name = get_midx_filename(object_dir);
+
+ fd = git_open(midx_name);
+ if (fd < 0)
+ return NULL;
+ if (fstat(fd, &st)) {
+ close(fd);
+ return NULL;
+ }
+ midx_size = xsize_t(st.st_size);
+
+ if (midx_size < MIDX_MIN_SIZE) {
+ close(fd);
+ die("multi-pack-index file %s is too small", midx_name);
+ }
+
+ midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
+
+ m = xcalloc(1, sizeof(*m) + strlen(object_dir) + 1);
+ strcpy(m->object_dir, object_dir);
+ m->data = midx_map;
+
+ m->signature = get_be32(m->data);
+ if (m->signature != MIDX_SIGNATURE) {
+ error("multi-pack-index signature %X does not match signature
%X",
+ m->signature, MIDX_SIGNATURE);
+ goto cleanup_fail;
+ }
+
+ m->version = *(m->data + 4);
+ if (m->version != MIDX_VERSION) {
+ error("multi-pack-index version %d not recognized",
+ m->version);
+ goto cleanup_fail;
+ }
+
+ m->hash_version = *(m->data + 5);
+ if (m->hash_version != MIDX_HASH_VERSION) {
+ error("hash version %d not recognized", m->hash_version);
+ goto cleanup_fail;
+ }
+ m->hash_len = MIDX_HASH_LEN;
+
+ m->num_chunks = *(m->data + 6);
+ m->num_packs = get_be32(m->data + 8);
+
+ return m;
+
+cleanup_fail:
+ FREE_AND_NULL(m);
+ munmap(midx_map, midx_size);
+ close(fd);
+ exit(1);
+}
+
static size_t write_midx_header(struct hashfile *f,
unsigned char num_chunks,
uint32_t num_packs)
diff --git a/midx.h b/midx.h
index 3a63673952..a1d18ed991 100644
--- a/midx.h
+++ b/midx.h
@@ -1,4 +1,13 @@
+#ifndef MIDX_H
+#define MIDX_H
+
+#include "git-compat-util.h"
#include "cache.h"
+#include "object-store.h"
#include "packfile.h"
+struct midxed_git *load_midxed_git(const char *object_dir);
+
int write_midx_file(const char *object_dir);
+
+#endif
diff --git a/object-store.h b/object-store.h
index d683112fd7..77cb82621a 100644
--- a/object-store.h
+++ b/object-store.h
@@ -84,6 +84,25 @@ struct packed_git {
char pack_name[FLEX_ARRAY]; /* more */
};
+struct midxed_git {
+ struct midxed_git *next;
+
+ int fd;
+
+ const unsigned char *data;
+ size_t data_len;
+
+ uint32_t signature;
+ unsigned char version;
+ unsigned char hash_version;
+ unsigned char hash_len;
+ unsigned char num_chunks;
+ uint32_t num_packs;
+ uint32_t num_objects;
+
+ char object_dir[FLEX_ARRAY];
+};
+
struct raw_object_store {
/*
* Path to the repository's object store.
diff --git a/t/t5319-midx.sh b/t/t5319-midx.sh
index 80f9389837..e78514d8e9 100755
--- a/t/t5319-midx.sh
+++ b/t/t5319-midx.sh
@@ -3,9 +3,19 @@
test_description='multi-pack-indexes'
. ./test-lib.sh
+midx_read_expect() {
+ cat >expect <<- EOF
+ header: 4d494458 1 1 0 0
+ object_dir: .
+ EOF
+ git midx read --object-dir=. >actual &&
+ test_cmp expect actual
+}
+
test_expect_success 'write midx with no packs' '
git midx --object-dir=. write &&
- test_path_is_file pack/multi-pack-index
+ test_path_is_file pack/multi-pack-index &&
+ midx_read_expect
'
test_done
--
2.18.0.rc1
