From 4d80560c546179654c32499132a6bdaf3c45b16f Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Thu, 12 Jul 2018 15:39:23 -0400 Subject: [PATCH] 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 Signed-off-by: Junio C Hamano --- Makefile | 1 + midx.c | 79 +++++++++++++++++++++++++++++++++++++ midx.h | 18 +++++++++ object-store.h | 2 + t/helper/test-read-midx.c | 31 +++++++++++++++ t/helper/test-tool.c | 1 + t/helper/test-tool.h | 1 + t/t5319-multi-pack-index.sh | 11 +++++- 8 files changed, 143 insertions(+), 1 deletion(-) create mode 100644 t/helper/test-read-midx.c diff --git a/Makefile b/Makefile index f5636c711d..0b801d1b16 100644 --- a/Makefile +++ b/Makefile @@ -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 diff --git a/midx.c b/midx.c index f85f2d334d..c1ff5acf85 100644 --- a/midx.c +++ b/midx.c @@ -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) diff --git a/midx.h b/midx.h index dbdbe9f873..0e05051bca 100644 --- a/midx.h +++ b/midx.h @@ -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 diff --git a/object-store.h b/object-store.h index d683112fd7..13a766aea8 100644 --- a/object-store.h +++ b/object-store.h @@ -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. diff --git a/t/helper/test-read-midx.c b/t/helper/test-read-midx.c new file mode 100644 index 0000000000..988a487169 --- /dev/null +++ b/t/helper/test-read-midx.c @@ -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 "); + + return read_midx_file(argv[1]); +} diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c index 805a45de9c..1c3ab36e6c 100644 --- a/t/helper/test-tool.c +++ b/t/helper/test-tool.c @@ -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 }, diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h index 7116ddfb94..6af8c08a66 100644 --- a/t/helper/test-tool.h +++ b/t/helper/test-tool.h @@ -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); diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh index 50e80f8f2c..506bd8abb8 100755 --- a/t/t5319-multi-pack-index.sh +++ b/t/t5319-multi-pack-index.sh @@ -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