[PATCH 07/32] loose: add a mapping between SHA-1 and SHA-256 for loose objects
- From
Eric W. Biederman <ebiederm@xmission.com>
- Date
- Sep 8, 2023, 23:10 UTC
- Message-ID
- <20230908231049.2035003-7-ebiederm@xmission.com>
- In-Reply-To
- <87sf7ol0z3.fsf@email.froward.int.ebiederm.org>
From: "brian m. carlson" <sandals@crustytoothpaste.net>
As part of the transition plan, we'd like to add a file in the .git directory that maps loose objects between SHA-1 and SHA-256. Let's implement the specification in the transition plan and store this data on a per-repository basis in struct repository.
**** - split repo_object_map between repo_loose_object_map_oid and repo_oid_to_algop. - Verified the loose_map is set in repo_loose_object_map_oid
-- EWB
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> --- Makefile | 1 + loose.c | 243 ++++++++++++++++++++++++++++++++++++++++++ loose.h | 20 ++++ object-file-convert.c | 14 ++- object-store-ll.h | 3 + object.c | 2 + repository.c | 6 ++ 7 files changed, 288 insertions(+), 1 deletion(-) create mode 100644 loose.c create mode 100644 loose.h
diff --git a/Makefile b/Makefile index f7e824f25cda..3c18664def9a 100644 --- a/Makefile +++ b/Makefile @@ -1053,6 +1053,7 @@ LIB_OBJS += list-objects-filter.o LIB_OBJS += list-objects.o LIB_OBJS += lockfile.o LIB_OBJS += log-tree.o +LIB_OBJS += loose.o LIB_OBJS += ls-refs.o LIB_OBJS += mailinfo.o LIB_OBJS += mailmap.o diff --git a/loose.c b/loose.c new file mode 100644 index 000000000000..8ddb7112a541 --- /dev/null +++ b/loose.c @@ -0,0 +1,243 @@ +#include "git-compat-util.h" +#include "hash.h" +#include "path.h" +#include "object-store.h" +#include "hex.h" +#include "wrapper.h" +#include "gettext.h" +#include "loose.h" +#include "lockfile.h" + +static const char *loose_object_header = "# loose-object-idx\n"; + +static inline int should_use_loose_object_map(struct repository *repo) +{ + return repo->compat_hash_algo && repo->gitdir; +} + +void loose_object_map_init(struct loose_object_map **map) +{ + struct loose_object_map *m; + m = xmalloc(sizeof(**map)); + m->to_compat = kh_init_oid_map(); + m->to_storage = kh_init_oid_map(); + *map = m; +} + +static int insert_oid_pair(kh_oid_map_t *map, const struct object_id *key, const struct object_id *value) +{ + khiter_t pos; + int ret; + struct object_id *stored; + + pos = kh_put_oid_map(map, *key, &ret); + + /* This item already exists in the map. */ + if (ret == 0) + return 0; + + stored = xmalloc(sizeof(*stored)); + oidcpy(stored, value); + kh_value(map, pos) = stored; + return 1; +} + +static int load_one_loose_object_map(struct repository *repo, struct object_directory *dir) +{ + struct strbuf buf = STRBUF_INIT, path = STRBUF_INIT; + FILE *fp; + + if (!dir->loose_map) + loose_object_map_init(&dir->loose_map); + + insert_oid_pair(dir->loose_map->to_compat, repo->hash_algo->empty_tree, repo->compat_hash_algo->empty_tree); + insert_oid_pair(dir->loose_map->to_storage, repo->compat_hash_algo->empty_tree, repo->hash_algo->empty_tree); + + insert_oid_pair(dir->loose_map->to_compat, repo->hash_algo->empty_blob, repo->compat_hash_algo->empty_blob); + insert_oid_pair(dir->loose_map->to_storage, repo->compat_hash_algo->empty_blob, repo->hash_algo->empty_blob); + + insert_oid_pair(dir->loose_map->to_compat, repo->hash_algo->null_oid, repo->compat_hash_algo->null_oid); + insert_oid_pair(dir->loose_map->to_storage, repo->compat_hash_algo->null_oid, repo->hash_algo->null_oid); + + strbuf_git_common_path(&path, repo, "objects/loose-object-idx"); + fp = fopen(path.buf, "rb"); + if (!fp) + return 0; + + errno = 0; + if (strbuf_getwholeline(&buf, fp, '\n') || strcmp(buf.buf, loose_object_header)) + goto err; + while (!strbuf_getline_lf(&buf, fp)) { + const char *p; + struct object_id oid, compat_oid; + if (parse_oid_hex_algop(buf.buf, &oid, &p, repo->hash_algo) || + *p++ != ' ' || + parse_oid_hex_algop(p, &compat_oid, &p, repo->compat_hash_algo) || + p != buf.buf + buf.len) + goto err; + insert_oid_pair(dir->loose_map->to_compat, &oid, &compat_oid); + insert_oid_pair(dir->loose_map->to_storage, &compat_oid, &oid); + } + + strbuf_release(&buf); + strbuf_release(&path); + return errno ? -1 : 0; +err: + strbuf_release(&buf); + strbuf_release(&path); + return -1; +} + +int repo_read_loose_object_map(struct repository *repo) +{ + struct object_directory *dir; + + if (!should_use_loose_object_map(repo)) + return 0; + + prepare_alt_odb(repo); + + for (dir = repo->objects->odb; dir; dir = dir->next) { + if (load_one_loose_object_map(repo, dir) < 0) { + return -1; + } + } + return 0; +} + +int repo_write_loose_object_map(struct repository *repo) +{ + kh_oid_map_t *map = repo->objects->odb->loose_map->to_compat; + struct lock_file lock; + int fd; + khiter_t iter; + struct strbuf buf = STRBUF_INIT, path = STRBUF_INIT; + + if (!should_use_loose_object_map(repo)) + return 0; + + strbuf_git_common_path(&path, repo, "objects/loose-object-idx"); + fd = hold_lock_file_for_update_timeout(&lock, path.buf, LOCK_DIE_ON_ERROR, -1); + iter = kh_begin(map); + if (write_in_full(fd, loose_object_header, strlen(loose_object_header)) < 0) + goto errout; + + for (; iter != kh_end(map); iter++) { + if (kh_exist(map, iter)) { + if (oideq(&kh_key(map, iter), the_hash_algo->empty_tree) || + oideq(&kh_key(map, iter), the_hash_algo->empty_blob)) + continue; + strbuf_addf(&buf, "%s %s\n", oid_to_hex(&kh_key(map, iter)), oid_to_hex(kh_value(map, iter))); + if (write_in_full(fd, buf.buf, buf.len) < 0) + goto errout; + strbuf_reset(&buf); + } + } + strbuf_release(&buf); + if (commit_lock_file(&lock) < 0) { + error_errno(_("could not write loose object index %s"), path.buf); + strbuf_release(&path); + return -1; + } + strbuf_release(&path); + return 0; +errout: + rollback_lock_file(&lock); + strbuf_release(&buf); + error_errno(_("failed to write loose object index %s\n"), path.buf); + strbuf_release(&path); + return -1; +} + +static int write_one_object(struct repository *repo, const struct object_id *oid, + const struct object_id *compat_oid) +{ + struct lock_file lock; + int fd; + struct stat st; + struct strbuf buf = STRBUF_INIT, path = STRBUF_INIT; + + strbuf_git_common_path(&path, repo, "objects/loose-object-idx"); + hold_lock_file_for_update_timeout(&lock, path.buf, LOCK_DIE_ON_ERROR, -1); + + fd = open(path.buf, O_WRONLY | O_CREAT | O_APPEND, 0666); + if (fd < 0) + goto errout; + if (fstat(fd, &st) < 0) + goto errout; + if (!st.st_size && write_in_full(fd, loose_object_header, strlen(loose_object_header)) < 0) + goto errout; + + strbuf_addf(&buf, "%s %s\n", oid_to_hex(oid), oid_to_hex(compat_oid)); + if (write_in_full(fd, buf.buf, buf.len) < 0) + goto errout; + if (close(fd)) + goto errout; + adjust_shared_perm(path.buf); + rollback_lock_file(&lock); + strbuf_release(&buf); + strbuf_release(&path); + return 0; +errout: + error_errno(_("failed to write loose object index %s\n"), path.buf); + close(fd); + rollback_lock_file(&lock); + strbuf_release(&buf); + strbuf_release(&path); + return -1; +} + +int repo_add_loose_object_map(struct repository *repo, const struct object_id *oid, + const struct object_id *compat_oid) +{ + int inserted = 0; + + if (!should_use_loose_object_map(repo)) + return 0; + + inserted |= insert_oid_pair(repo->objects->odb->loose_map->to_compat, oid, compat_oid); + inserted |= insert_oid_pair(repo->objects->odb->loose_map->to_storage, compat_oid, oid); + if (inserted) + return write_one_object(repo, oid, compat_oid); + return 0; +} + +int repo_loose_object_map_oid(struct repository *repo, struct object_id *dest, + const struct git_hash_algo *to, + const struct object_id *src) +{ + struct object_directory *dir; + kh_oid_map_t *map; + khiter_t pos; + + for (dir = repo->objects->odb; dir; dir = dir->next) { + struct loose_object_map *loose_map = dir->loose_map; + if (!loose_map) + continue; + map = (to == repo->compat_hash_algo) ? + loose_map->to_compat : + loose_map->to_storage; + pos = kh_get_oid_map(map, *src); + if (pos < kh_end(map)) { + oidcpy(dest, kh_value(map, pos)); + return 0; + } + } + return -1; +} + +void loose_object_map_clear(struct loose_object_map **map) +{ + struct loose_object_map *m = *map; + struct object_id *oid; + + if (!m) + return; + + kh_foreach_value(m->to_compat, oid, free(oid)); + kh_foreach_value(m->to_storage, oid, free(oid)); + kh_destroy_oid_map(m->to_compat); + kh_destroy_oid_map(m->to_storage); + free(m); + *map = NULL; +} diff --git a/loose.h b/loose.h new file mode 100644 index 000000000000..061c6937aead --- /dev/null +++ b/loose.h @@ -0,0 +1,20 @@ +#ifndef LOOSE_H +#define LOOSE_H + +#include "khash.h" + +struct loose_object_map { + kh_oid_map_t *to_compat; + kh_oid_map_t *to_storage; +}; + +void loose_object_map_init(struct loose_object_map **map); +void loose_object_map_clear(struct loose_object_map **map); +int repo_loose_object_map_oid(struct repository *repo, struct object_id *dest, + const struct git_hash_algo *dest_algo, const struct object_id *src); +int repo_add_loose_object_map(struct repository *repo, const struct object_id *oid, + const struct object_id *compat_oid); +int repo_read_loose_object_map(struct repository *repo); +int repo_write_loose_object_map(struct repository *repo); + +#endif diff --git a/object-file-convert.c b/object-file-convert.c index 9f4d5b354f5f..e7c62434016d 100644 --- a/object-file-convert.c +++ b/object-file-convert.c @@ -4,6 +4,7 @@ #include "repository.h" #include "hash-ll.h" #include "object.h" +#include "loose.h" #include "object-file-convert.h" int repo_oid_to_algop(struct repository *repo, const struct object_id *src, @@ -21,7 +22,18 @@ int repo_oid_to_algop(struct repository *repo, const struct object_id *src, oidcpy(dest, src); return 0; } - return -1; + if (repo_loose_object_map_oid(repo, dest, to, src)) { + /* + * We may have loaded the object map at repo initialization but + * another process (perhaps upstream of a pipe from us) may have + * written a new object into the map. If the object is missing, + * let's reload the map to see if the object has appeared. + */ + repo_read_loose_object_map(repo); + if (repo_loose_object_map_oid(repo, dest, to, src)) + return -1; + } + return 0; } int convert_object_file(struct strbuf *outbuf, diff --git a/object-store-ll.h b/object-store-ll.h index 26a3895c821c..bc76d6bec80d 100644 --- a/object-store-ll.h +++ b/object-store-ll.h @@ -26,6 +26,9 @@ struct object_directory { uint32_t loose_objects_subdir_seen[8]; /* 256 bits */ struct oidtree *loose_objects_cache; + /* Map between object IDs for loose objects. */ + struct loose_object_map *loose_map; + /* * This is a temporary object store created by the tmp_objdir * facility. Disable ref updates since the objects in the store diff --git a/object.c b/object.c index 2c61e4c86217..186a0a47c0fb 100644 --- a/object.c +++ b/object.c @@ -13,6 +13,7 @@ #include "alloc.h" #include "packfile.h" #include "commit-graph.h" +#include "loose.h" unsigned int get_max_object_index(void) { @@ -540,6 +541,7 @@ void free_object_directory(struct object_directory *odb) { free(odb->path); odb_clear_loose_cache(odb); + loose_object_map_clear(&odb->loose_map); free(odb); } diff --git a/repository.c b/repository.c index de620d82bfc6..4ab44d3b0344 100644 --- a/repository.c +++ b/repository.c @@ -14,6 +14,7 @@ #include "read-cache-ll.h" #include "remote.h" #include "setup.h" +#include "loose.h" #include "submodule-config.h" #include "sparse-index.h" #include "trace2.h" @@ -112,6 +113,8 @@ void repo_enable_compat_map(struct repository *repo, int enable_compat) GIT_HASH_SHA1]; repo->compat_hash_algo = enable_compat ? other_algo : NULL; + if (enable_compat) + repo_read_loose_object_map(repo); } /* @@ -204,6 +207,9 @@ int repo_init(struct repository *repo, if (worktree) repo_set_worktree(repo, worktree); + if (repo->compat_hash_algo) + repo_read_loose_object_map(repo); + clear_repository_format(&format); return 0;
-- 2.41.0