diff options
Diffstat (limited to 'packfile.c')
| -rw-r--r-- | packfile.c | 1952 |
1 files changed, 1952 insertions, 0 deletions
diff --git a/packfile.c b/packfile.c new file mode 100644 index 0000000000..7c1a2519fc --- /dev/null +++ b/packfile.c @@ -0,0 +1,1952 @@ +#include "cache.h" +#include "list.h" +#include "pack.h" +#include "dir.h" +#include "mergesort.h" +#include "packfile.h" +#include "delta.h" +#include "list.h" +#include "streaming.h" +#include "sha1-lookup.h" +#include "commit.h" +#include "object.h" +#include "tag.h" +#include "tree-walk.h" +#include "tree.h" + +char *odb_pack_name(struct strbuf *buf, + const unsigned char *sha1, + const char *ext) +{ + strbuf_reset(buf); + strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(), + sha1_to_hex(sha1), ext); + return buf->buf; +} + +char *sha1_pack_name(const unsigned char *sha1) +{ + static struct strbuf buf = STRBUF_INIT; + return odb_pack_name(&buf, sha1, "pack"); +} + +char *sha1_pack_index_name(const unsigned char *sha1) +{ + static struct strbuf buf = STRBUF_INIT; + return odb_pack_name(&buf, sha1, "idx"); +} + +static unsigned int pack_used_ctr; +static unsigned int pack_mmap_calls; +static unsigned int peak_pack_open_windows; +static unsigned int pack_open_windows; +static unsigned int pack_open_fds; +static unsigned int pack_max_fds; +static size_t peak_pack_mapped; +static size_t pack_mapped; +struct packed_git *packed_git; +LIST_HEAD(packed_git_mru); + +#define SZ_FMT PRIuMAX +static inline uintmax_t sz_fmt(size_t s) { return s; } + +void pack_report(void) +{ + fprintf(stderr, + "pack_report: getpagesize() = %10" SZ_FMT "\n" + "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n" + "pack_report: core.packedGitLimit = %10" SZ_FMT "\n", + sz_fmt(getpagesize()), + sz_fmt(packed_git_window_size), + sz_fmt(packed_git_limit)); + fprintf(stderr, + "pack_report: pack_used_ctr = %10u\n" + "pack_report: pack_mmap_calls = %10u\n" + "pack_report: pack_open_windows = %10u / %10u\n" + "pack_report: pack_mapped = " + "%10" SZ_FMT " / %10" SZ_FMT "\n", + pack_used_ctr, + pack_mmap_calls, + pack_open_windows, peak_pack_open_windows, + sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped)); +} + +/* + * Open and mmap the index file at path, perform a couple of + * consistency checks, then record its information to p. Return 0 on + * success. + */ +static int check_packed_git_idx(const char *path, struct packed_git *p) +{ + void *idx_map; + struct pack_idx_header *hdr; + size_t idx_size; + uint32_t version, nr, i, *index; + int fd = git_open(path); + struct stat st; + + if (fd < 0) + return -1; + if (fstat(fd, &st)) { + close(fd); + return -1; + } + idx_size = xsize_t(st.st_size); + if (idx_size < 4 * 256 + 20 + 20) { + close(fd); + return error("index file %s is too small", path); + } + idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0); + close(fd); + + hdr = idx_map; + if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) { + version = ntohl(hdr->idx_version); + if (version < 2 || version > 2) { + munmap(idx_map, idx_size); + return error("index file %s is version %"PRIu32 + " and is not supported by this binary" + " (try upgrading GIT to a newer version)", + path, version); + } + } else + version = 1; + + nr = 0; + index = idx_map; + if (version > 1) + index += 2; /* skip index header */ + for (i = 0; i < 256; i++) { + uint32_t n = ntohl(index[i]); + if (n < nr) { + munmap(idx_map, idx_size); + return error("non-monotonic index %s", path); + } + nr = n; + } + + if (version == 1) { + /* + * Total size: + * - 256 index entries 4 bytes each + * - 24-byte entries * nr (20-byte sha1 + 4-byte offset) + * - 20-byte SHA1 of the packfile + * - 20-byte SHA1 file checksum + */ + if (idx_size != 4*256 + nr * 24 + 20 + 20) { + munmap(idx_map, idx_size); + return error("wrong index v1 file size in %s", path); + } + } else if (version == 2) { + /* + * Minimum size: + * - 8 bytes of header + * - 256 index entries 4 bytes each + * - 20-byte sha1 entry * nr + * - 4-byte crc entry * nr + * - 4-byte offset entry * nr + * - 20-byte SHA1 of the packfile + * - 20-byte SHA1 file checksum + * And after the 4-byte offset table might be a + * variable sized table containing 8-byte entries + * for offsets larger than 2^31. + */ + unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20; + unsigned long max_size = min_size; + if (nr) + max_size += (nr - 1)*8; + if (idx_size < min_size || idx_size > max_size) { + munmap(idx_map, idx_size); + return error("wrong index v2 file size in %s", path); + } + if (idx_size != min_size && + /* + * make sure we can deal with large pack offsets. + * 31-bit signed offset won't be enough, neither + * 32-bit unsigned one will be. + */ + (sizeof(off_t) <= 4)) { + munmap(idx_map, idx_size); + return error("pack too large for current definition of off_t in %s", path); + } + } + + p->index_version = version; + p->index_data = idx_map; + p->index_size = idx_size; + p->num_objects = nr; + return 0; +} + +int open_pack_index(struct packed_git *p) +{ + char *idx_name; + size_t len; + int ret; + + if (p->index_data) + return 0; + + if (!strip_suffix(p->pack_name, ".pack", &len)) + die("BUG: pack_name does not end in .pack"); + idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name); + ret = check_packed_git_idx(idx_name, p); + free(idx_name); + return ret; +} + +static struct packed_git *alloc_packed_git(int extra) +{ + struct packed_git *p = xmalloc(st_add(sizeof(*p), extra)); + memset(p, 0, sizeof(*p)); + p->pack_fd = -1; + return p; +} + +struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path) +{ + const char *path = sha1_pack_name(sha1); + size_t alloc = st_add(strlen(path), 1); + struct packed_git *p = alloc_packed_git(alloc); + + memcpy(p->pack_name, path, alloc); /* includes NUL */ + hashcpy(p->sha1, sha1); + if (check_packed_git_idx(idx_path, p)) { + free(p); + return NULL; + } + + return p; +} + +static void scan_windows(struct packed_git *p, + struct packed_git **lru_p, + struct pack_window **lru_w, + struct pack_window **lru_l) +{ + struct pack_window *w, *w_l; + + for (w_l = NULL, w = p->windows; w; w = w->next) { + if (!w->inuse_cnt) { + if (!*lru_w || w->last_used < (*lru_w)->last_used) { + *lru_p = p; + *lru_w = w; + *lru_l = w_l; + } + } + w_l = w; + } +} + +static int unuse_one_window(struct packed_git *current) +{ + struct packed_git *p, *lru_p = NULL; + struct pack_window *lru_w = NULL, *lru_l = NULL; + + if (current) + scan_windows(current, &lru_p, &lru_w, &lru_l); + for (p = packed_git; p; p = p->next) + scan_windows(p, &lru_p, &lru_w, &lru_l); + if (lru_p) { + munmap(lru_w->base, lru_w->len); + pack_mapped -= lru_w->len; + if (lru_l) + lru_l->next = lru_w->next; + else + lru_p->windows = lru_w->next; + free(lru_w); + pack_open_windows--; + return 1; + } + return 0; +} + +void release_pack_memory(size_t need) +{ + size_t cur = pack_mapped; + while (need >= (cur - pack_mapped) && unuse_one_window(NULL)) + ; /* nothing */ +} + +void close_pack_windows(struct packed_git *p) +{ + while (p->windows) { + struct pack_window *w = p->windows; + + if (w->inuse_cnt) + die("pack '%s' still has open windows to it", + p->pack_name); + munmap(w->base, w->len); + pack_mapped -= w->len; + pack_open_windows--; + p->windows = w->next; + free(w); + } +} + +static int close_pack_fd(struct packed_git *p) +{ + if (p->pack_fd < 0) + return 0; + + close(p->pack_fd); + pack_open_fds--; + p->pack_fd = -1; + + return 1; +} + +void close_pack_index(struct packed_git *p) +{ + if (p->index_data) { + munmap((void *)p->index_data, p->index_size); + p->index_data = NULL; + } +} + +static void close_pack(struct packed_git *p) +{ + close_pack_windows(p); + close_pack_fd(p); + close_pack_index(p); +} + +void close_all_packs(void) +{ + struct packed_git *p; + + for (p = packed_git; p; p = p->next) + if (p->do_not_close) + die("BUG: want to close pack marked 'do-not-close'"); + else + close_pack(p); +} + +/* + * The LRU pack is the one with the oldest MRU window, preferring packs + * with no used windows, or the oldest mtime if it has no windows allocated. + */ +static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse) +{ + struct pack_window *w, *this_mru_w; + int has_windows_inuse = 0; + + /* + * Reject this pack if it has windows and the previously selected + * one does not. If this pack does not have windows, reject + * it if the pack file is newer than the previously selected one. + */ + if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime)) + return; + + for (w = this_mru_w = p->windows; w; w = w->next) { + /* + * Reject this pack if any of its windows are in use, + * but the previously selected pack did not have any + * inuse windows. Otherwise, record that this pack + * has windows in use. + */ + if (w->inuse_cnt) { + if (*accept_windows_inuse) + has_windows_inuse = 1; + else + return; + } + + if (w->last_used > this_mru_w->last_used) + this_mru_w = w; + + /* + * Reject this pack if it has windows that have been + * used more recently than the previously selected pack. + * If the previously selected pack had windows inuse and + * we have not encountered a window in this pack that is + * inuse, skip this check since we prefer a pack with no + * inuse windows to one that has inuse windows. + */ + if (*mru_w && *accept_windows_inuse == has_windows_inuse && + this_mru_w->last_used > (*mru_w)->last_used) + return; + } + + /* + * Select this pack. + */ + *mru_w = this_mru_w; + *lru_p = p; + *accept_windows_inuse = has_windows_inuse; +} + +static int close_one_pack(void) +{ + struct packed_git *p, *lru_p = NULL; + struct pack_window *mru_w = NULL; + int accept_windows_inuse = 1; + + for (p = packed_git; p; p = p->next) { + if (p->pack_fd == -1) + continue; + find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse); + } + + if (lru_p) + return close_pack_fd(lru_p); + + return 0; +} + +static unsigned int get_max_fd_limit(void) +{ +#ifdef RLIMIT_NOFILE + { + struct rlimit lim; + + if (!getrlimit(RLIMIT_NOFILE, &lim)) + return lim.rlim_cur; + } +#endif + +#ifdef _SC_OPEN_MAX + { + long open_max = sysconf(_SC_OPEN_MAX); + if (0 < open_max) + return open_max; + /* + * Otherwise, we got -1 for one of the two + * reasons: + * + * (1) sysconf() did not understand _SC_OPEN_MAX + * and signaled an error with -1; or + * (2) sysconf() said there is no limit. + * + * We _could_ clear errno before calling sysconf() to + * tell these two cases apart and return a huge number + * in the latter case to let the caller cap it to a + * value that is not so selfish, but letting the + * fallback OPEN_MAX codepath take care of these cases + * is a lot simpler. + */ + } +#endif + +#ifdef OPEN_MAX + return OPEN_MAX; +#else + return 1; /* see the caller ;-) */ +#endif +} + +/* + * Do not call this directly as this leaks p->pack_fd on error return; + * call open_packed_git() instead. + */ +static int open_packed_git_1(struct packed_git *p) +{ + struct stat st; + struct pack_header hdr; + unsigned char sha1[20]; + unsigned char *idx_sha1; + long fd_flag; + ssize_t read_result; + + if (!p->index_data && open_pack_index(p)) + return error("packfile %s index unavailable", p->pack_name); + + if (!pack_max_fds) { + unsigned int max_fds = get_max_fd_limit(); + + /* Save 3 for stdin/stdout/stderr, 22 for work */ + if (25 < max_fds) + pack_max_fds = max_fds - 25; + else + pack_max_fds = 1; + } + + while (pack_max_fds <= pack_open_fds && close_one_pack()) + ; /* nothing */ + + p->pack_fd = git_open(p->pack_name); + if (p->pack_fd < 0 || fstat(p->pack_fd, &st)) + return -1; + pack_open_fds++; + + /* If we created the struct before we had the pack we lack size. */ + if (!p->pack_size) { + if (!S_ISREG(st.st_mode)) + return error("packfile %s not a regular file", p->pack_name); + p->pack_size = st.st_size; + } else if (p->pack_size != st.st_size) + return error("packfile %s size changed", p->pack_name); + + /* We leave these file descriptors open with sliding mmap; + * there is no point keeping them open across exec(), though. + */ + fd_flag = fcntl(p->pack_fd, F_GETFD, 0); + if (fd_flag < 0) + return error("cannot determine file descriptor flags"); + fd_flag |= FD_CLOEXEC; + if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1) + return error("cannot set FD_CLOEXEC"); + + /* Verify we recognize this pack file format. */ + read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr)); + if (read_result < 0) + return error_errno("error reading from %s", p->pack_name); + if (read_result != sizeof(hdr)) + return error("file %s is far too short to be a packfile", p->pack_name); + if (hdr.hdr_signature != htonl(PACK_SIGNATURE)) + return error("file %s is not a GIT packfile", p->pack_name); + if (!pack_version_ok(hdr.hdr_version)) + return error("packfile %s is version %"PRIu32" and not" + " supported (try upgrading GIT to a newer version)", + p->pack_name, ntohl(hdr.hdr_version)); + + /* Verify the pack matches its index. */ + if (p->num_objects != ntohl(hdr.hdr_entries)) + return error("packfile %s claims to have %"PRIu32" objects" + " while index indicates %"PRIu32" objects", + p->pack_name, ntohl(hdr.hdr_entries), + p->num_objects); + if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1) + return error("end of packfile %s is unavailable", p->pack_name); + read_result = read_in_full(p->pack_fd, sha1, sizeof(sha1)); + if (read_result < 0) + return error_errno("error reading from %s", p->pack_name); + if (read_result != sizeof(sha1)) + return error("packfile %s signature is unavailable", p->pack_name); + idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40; + if (hashcmp(sha1, idx_sha1)) + return error("packfile %s does not match index", p->pack_name); + return 0; +} + +static int open_packed_git(struct packed_git *p) +{ + if (!open_packed_git_1(p)) + return 0; + close_pack_fd(p); + return -1; +} + +static int in_window(struct pack_window *win, off_t offset) +{ + /* We must promise at least 20 bytes (one hash) after the + * offset is available from this window, otherwise the offset + * is not actually in this window and a different window (which + * has that one hash excess) must be used. This is to support + * the object header and delta base parsing routines below. + */ + off_t win_off = win->offset; + return win_off <= offset + && (offset + 20) <= (win_off + win->len); +} + +unsigned char *use_pack(struct packed_git *p, + struct pack_window **w_cursor, + off_t offset, + unsigned long *left) +{ + struct pack_window *win = *w_cursor; + + /* Since packfiles end in a hash of their content and it's + * pointless to ask for an offset into the middle of that + * hash, and the in_window function above wouldn't match + * don't allow an offset too close to the end of the file. + */ + if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p)) + die("packfile %s cannot be accessed", p->pack_name); + if (offset > (p->pack_size - 20)) + die("offset beyond end of packfile (truncated pack?)"); + if (offset < 0) + die(_("offset before end of packfile (broken .idx?)")); + + if (!win || !in_window(win, offset)) { + if (win) + win->inuse_cnt--; + for (win = p->windows; win; win = win->next) { + if (in_window(win, offset)) + break; + } + if (!win) { + size_t window_align = packed_git_window_size / 2; + off_t len; + + if (p->pack_fd == -1 && open_packed_git(p)) + die("packfile %s cannot be accessed", p->pack_name); + + win = xcalloc(1, sizeof(*win)); + win->offset = (offset / window_align) * window_align; + len = p->pack_size - win->offset; + if (len > packed_git_window_size) + len = packed_git_window_size; + win->len = (size_t)len; + pack_mapped += win->len; + while (packed_git_limit < pack_mapped + && unuse_one_window(p)) + ; /* nothing */ + win->base = xmmap(NULL, win->len, + PROT_READ, MAP_PRIVATE, + p->pack_fd, win->offset); + if (win->base == MAP_FAILED) + die_errno("packfile %s cannot be mapped", + p->pack_name); + if (!win->offset && win->len == p->pack_size + && !p->do_not_close) + close_pack_fd(p); + pack_mmap_calls++; + pack_open_windows++; + if (pack_mapped > peak_pack_mapped) + peak_pack_mapped = pack_mapped; + if (pack_open_windows > peak_pack_open_windows) + peak_pack_open_windows = pack_open_windows; + win->next = p->windows; + p->windows = win; + } + } + if (win != *w_cursor) { + win->last_used = pack_used_ctr++; + win->inuse_cnt++; + *w_cursor = win; + } + offset -= win->offset; + if (left) + *left = win->len - xsize_t(offset); + return win->base + offset; +} + +void unuse_pack(struct pack_window **w_cursor) +{ + struct pack_window *w = *w_cursor; + if (w) { + w->inuse_cnt--; + *w_cursor = NULL; + } +} + +static void try_to_free_pack_memory(size_t size) +{ + release_pack_memory(size); +} + +struct packed_git *add_packed_git(const char *path, size_t path_len, int local) +{ + static int have_set_try_to_free_routine; + struct stat st; + size_t alloc; + struct packed_git *p; + + if (!have_set_try_to_free_routine) { + have_set_try_to_free_routine = 1; + set_try_to_free_routine(try_to_free_pack_memory); + } + + /* + * Make sure a corresponding .pack file exists and that + * the index looks sane. + */ + if (!strip_suffix_mem(path, &path_len, ".idx")) + return NULL; + + /* + * ".promisor" is long enough to hold any suffix we're adding (and + * the use xsnprintf double-checks that) + */ + alloc = st_add3(path_len, strlen(".promisor"), 1); + p = alloc_packed_git(alloc); + memcpy(p->pack_name, path, path_len); + + xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep"); + if (!access(p->pack_name, F_OK)) + p->pack_keep = 1; + + xsnprintf(p->pack_name + path_len, alloc - path_len, ".promisor"); + if (!access(p->pack_name, F_OK)) + p->pack_promisor = 1; + + xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack"); + if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) { + free(p); + return NULL; + } + + /* ok, it looks sane as far as we can check without + * actually mapping the pack file. + */ + p->pack_size = st.st_size; + p->pack_local = local; + p->mtime = st.st_mtime; + if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1)) + hashclr(p->sha1); + return p; +} + +void install_packed_git(struct packed_git *pack) +{ + if (pack->pack_fd != -1) + pack_open_fds++; + + pack->next = packed_git; + packed_git = pack; +} + +void (*report_garbage)(unsigned seen_bits, const char *path); + +static void report_helper(const struct string_list *list, + int seen_bits, int first, int last) +{ + if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX)) + return; + + for (; first < last; first++) + report_garbage(seen_bits, list->items[first].string); +} + +static void report_pack_garbage(struct string_list *list) +{ + int i, baselen = -1, first = 0, seen_bits = 0; + + if (!report_garbage) + return; + + string_list_sort(list); + + for (i = 0; i < list->nr; i++) { + const char *path = list->items[i].string; + if (baselen != -1 && + strncmp(path, list->items[first].string, baselen)) { + report_helper(list, seen_bits, first, i); + baselen = -1; + seen_bits = 0; + } + if (baselen == -1) { + const char *dot = strrchr(path, '.'); + if (!dot) { + report_garbage(PACKDIR_FILE_GARBAGE, path); + continue; + } + baselen = dot - path + 1; + first = i; + } + if (!strcmp(path + baselen, "pack")) + seen_bits |= 1; + else if (!strcmp(path + baselen, "idx")) + seen_bits |= 2; + } + report_helper(list, seen_bits, first, list->nr); +} + +static void prepare_packed_git_one(char *objdir, int local) +{ + struct strbuf path = STRBUF_INIT; + size_t dirnamelen; + DIR *dir; + struct dirent *de; + struct string_list garbage = STRING_LIST_INIT_DUP; + + strbuf_addstr(&path, objdir); + strbuf_addstr(&path, "/pack"); + dir = opendir(path.buf); + if (!dir) { + if (errno != ENOENT) + error_errno("unable to open object pack directory: %s", + path.buf); + strbuf_release(&path); + return; + } + strbuf_addch(&path, '/'); + dirnamelen = path.len; + while ((de = readdir(dir)) != NULL) { + struct packed_git *p; + size_t base_len; + + if (is_dot_or_dotdot(de->d_name)) + continue; + + strbuf_setlen(&path, dirnamelen); + strbuf_addstr(&path, de->d_name); + + base_len = path.len; + if (strip_suffix_mem(path.buf, &base_len, ".idx")) { + /* Don't reopen a pack we already have. */ + for (p = packed_git; p; p = p->next) { + size_t len; + if (strip_suffix(p->pack_name, ".pack", &len) && + len == base_len && + !memcmp(p->pack_name, path.buf, len)) + break; + } + if (p == NULL && + /* + * See if it really is a valid .idx file with + * corresponding .pack file that we can map. + */ + (p = add_packed_git(path.buf, path.len, local)) != NULL) + install_packed_git(p); + } + + if (!report_garbage) + continue; + + if (ends_with(de->d_name, ".idx") || + ends_with(de->d_name, ".pack") || + ends_with(de->d_name, ".bitmap") || + ends_with(de->d_name, ".keep") || + ends_with(de->d_name, ".promisor")) + string_list_append(&garbage, path.buf); + else + report_garbage(PACKDIR_FILE_GARBAGE, path.buf); + } + closedir(dir); + report_pack_garbage(&garbage); + string_list_clear(&garbage, 0); + strbuf_release(&path); +} + +static int approximate_object_count_valid; + +/* + * Give a fast, rough count of the number of objects in the repository. This + * ignores loose objects completely. If you have a lot of them, then either + * you should repack because your performance will be awful, or they are + * all unreachable objects about to be pruned, in which case they're not really + * interesting as a measure of repo size in the first place. + */ +unsigned long approximate_object_count(void) +{ + static unsigned long count; + if (!approximate_object_count_valid) { + struct packed_git *p; + + prepare_packed_git(); + count = 0; + for (p = packed_git; p; p = p->next) { + if (open_pack_index(p)) + continue; + count += p->num_objects; + } + } + return count; +} + +static void *get_next_packed_git(const void *p) +{ + return ((const struct packed_git *)p)->next; +} + +static void set_next_packed_git(void *p, void *next) +{ + ((struct packed_git *)p)->next = next; +} + +static int sort_pack(const void *a_, const void *b_) +{ + const struct packed_git *a = a_; + const struct packed_git *b = b_; + int st; + + /* + * Local packs tend to contain objects specific to our + * variant of the project than remote ones. In addition, + * remote ones could be on a network mounted filesystem. + * Favor local ones for these reasons. + */ + st = a->pack_local - b->pack_local; + if (st) + return -st; + + /* + * Younger packs tend to contain more recent objects, + * and more recent objects tend to get accessed more + * often. + */ + if (a->mtime < b->mtime) + return 1; + else if (a->mtime == b->mtime) + return 0; + return -1; +} + +static void rearrange_packed_git(void) +{ + packed_git = llist_mergesort(packed_git, get_next_packed_git, + set_next_packed_git, sort_pack); +} + +static void prepare_packed_git_mru(void) +{ + struct packed_git *p; + + INIT_LIST_HEAD(&packed_git_mru); + + for (p = packed_git; p; p = p->next) + list_add_tail(&p->mru, &packed_git_mru); +} + +static int prepare_packed_git_run_once = 0; +void prepare_packed_git(void) +{ + struct alternate_object_database *alt; + + if (prepare_packed_git_run_once) + return; + prepare_packed_git_one(get_object_directory(), 1); + prepare_alt_odb(); + for (alt = alt_odb_list; alt; alt = alt->next) + prepare_packed_git_one(alt->path, 0); + rearrange_packed_git(); + prepare_packed_git_mru(); + prepare_packed_git_run_once = 1; +} + +void reprepare_packed_git(void) +{ + approximate_object_count_valid = 0; + prepare_packed_git_run_once = 0; + prepare_packed_git(); +} + +unsigned long unpack_object_header_buffer(const unsigned char *buf, + unsigned long len, enum object_type *type, unsigned long *sizep) +{ + unsigned shift; + unsigned long size, c; + unsigned long used = 0; + + c = buf[used++]; + *type = (c >> 4) & 7; + size = c & 15; + shift = 4; + while (c & 0x80) { + if (len <= used || bitsizeof(long) <= shift) { + error("bad object header"); + size = used = 0; + break; + } + c = buf[used++]; + size += (c & 0x7f) << shift; + shift += 7; + } + *sizep = size; + return used; +} + +unsigned long get_size_from_delta(struct packed_git *p, + struct pack_window **w_curs, + off_t curpos) +{ + const unsigned char *data; + unsigned char delta_head[20], *in; + git_zstream stream; + int st; + + memset(&stream, 0, sizeof(stream)); + stream.next_out = delta_head; + stream.avail_out = sizeof(delta_head); + + git_inflate_init(&stream); + do { + in = use_pack(p, w_curs, curpos, &stream.avail_in); + stream.next_in = in; + st = git_inflate(&stream, Z_FINISH); + curpos += stream.next_in - in; + } while ((st == Z_OK || st == Z_BUF_ERROR) && + stream.total_out < sizeof(delta_head)); + git_inflate_end(&stream); + if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) { + error("delta data unpack-initial failed"); + return 0; + } + + /* Examine the initial part of the delta to figure out + * the result size. + */ + data = delta_head; + + /* ignore base size */ + get_delta_hdr_size(&data, delta_head+sizeof(delta_head)); + + /* Read the result size */ + return get_delta_hdr_size(&data, delta_head+sizeof(delta_head)); +} + +int unpack_object_header(struct packed_git *p, + struct pack_window **w_curs, + off_t *curpos, + unsigned long *sizep) +{ + unsigned char *base; + unsigned long left; + unsigned long used; + enum object_type type; + + /* use_pack() assures us we have [base, base + 20) available + * as a range that we can look at. (Its actually the hash + * size that is assured.) With our object header encoding + * the maximum deflated object size is 2^137, which is just + * insane, so we know won't exceed what we have been given. + */ + base = use_pack(p, w_curs, *curpos, &left); + used = unpack_object_header_buffer(base, left, &type, sizep); + if (!used) { + type = OBJ_BAD; + } else + *curpos += used; + + return type; +} + +void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1) +{ + unsigned i; + for (i = 0; i < p->num_bad_objects; i++) + if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i)) + return; + p->bad_object_sha1 = xrealloc(p->bad_object_sha1, + st_mult(GIT_MAX_RAWSZ, + st_add(p->num_bad_objects, 1))); + hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1); + p->num_bad_objects++; +} + +const struct packed_git *has_packed_and_bad(const unsigned char *sha1) +{ + struct packed_git *p; + unsigned i; + + for (p = packed_git; p; p = p->next) + for (i = 0; i < p->num_bad_objects; i++) + if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i)) + return p; + return NULL; +} + +static off_t get_delta_base(struct packed_git *p, + struct pack_window **w_curs, + off_t *curpos, + enum object_type type, + off_t delta_obj_offset) +{ + unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL); + off_t base_offset; + + /* use_pack() assured us we have [base_info, base_info + 20) + * as a range that we can look at without walking off the + * end of the mapped window. Its actually the hash size + * that is assured. An OFS_DELTA longer than the hash size + * is stupid, as then a REF_DELTA would be smaller to store. + */ + if (type == OBJ_OFS_DELTA) { + unsigned used = 0; + unsigned char c = base_info[used++]; + base_offset = c & 127; + while (c & 128) { + base_offset += 1; + if (!base_offset || MSB(base_offset, 7)) + return 0; /* overflow */ + c = base_info[used++]; + base_offset = (base_offset << 7) + (c & 127); + } + base_offset = delta_obj_offset - base_offset; + if (base_offset <= 0 || base_offset >= delta_obj_offset) + return 0; /* out of bound */ + *curpos += used; + } else if (type == OBJ_REF_DELTA) { + /* The base entry _must_ be in the same pack */ + base_offset = find_pack_entry_one(base_info, p); + *curpos += 20; + } else + die("I am totally screwed"); + return base_offset; +} + +/* + * Like get_delta_base above, but we return the sha1 instead of the pack + * offset. This means it is cheaper for REF deltas (we do not have to do + * the final object lookup), but more expensive for OFS deltas (we + * have to load the revidx to convert the offset back into a sha1). + */ +static const unsigned char *get_delta_base_sha1(struct packed_git *p, + struct pack_window **w_curs, + off_t curpos, + enum object_type type, + off_t delta_obj_offset) +{ + if (type == OBJ_REF_DELTA) { + unsigned char *base = use_pack(p, w_curs, curpos, NULL); + return base; + } else if (type == OBJ_OFS_DELTA) { + struct revindex_entry *revidx; + off_t base_offset = get_delta_base(p, w_curs, &curpos, + type, delta_obj_offset); + + if (!base_offset) + return NULL; + + revidx = find_pack_revindex(p, base_offset); + if (!revidx) + return NULL; + + return nth_packed_object_sha1(p, revidx->nr); + } else + return NULL; +} + +static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset) +{ + int type; + struct revindex_entry *revidx; + const unsigned char *sha1; + revidx = find_pack_revindex(p, obj_offset); + if (!revidx) + return OBJ_BAD; + sha1 = nth_packed_object_sha1(p, revidx->nr); + mark_bad_packed_object(p, sha1); + type = sha1_object_info(sha1, NULL); + if (type <= OBJ_NONE) + return OBJ_BAD; + return type; +} + +#define POI_STACK_PREALLOC 64 + +static enum object_type packed_to_object_type(struct packed_git *p, + off_t obj_offset, + enum object_type type, + struct pack_window **w_curs, + off_t curpos) +{ + off_t small_poi_stack[POI_STACK_PREALLOC]; + off_t *poi_stack = small_poi_stack; + int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC; + + while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { + off_t base_offset; + unsigned long size; + /* Push the object we're going to leave behind */ + if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) { + poi_stack_alloc = alloc_nr(poi_stack_nr); + ALLOC_ARRAY(poi_stack, poi_stack_alloc); + memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr); + } else { + ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc); + } + poi_stack[poi_stack_nr++] = obj_offset; + /* If parsing the base offset fails, just unwind */ + base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset); + if (!base_offset) + goto unwind; + curpos = obj_offset = base_offset; + type = unpack_object_header(p, w_curs, &curpos, &size); + if (type <= OBJ_NONE) { + /* If getting the base itself fails, we first + * retry the base, otherwise unwind */ + type = retry_bad_packed_offset(p, base_offset); + if (type > OBJ_NONE) + goto out; + goto unwind; + } + } + + switch (type) { + case OBJ_BAD: + case OBJ_COMMIT: + case OBJ_TREE: + case OBJ_BLOB: + case OBJ_TAG: + break; + default: + error("unknown object type %i at offset %"PRIuMAX" in %s", + type, (uintmax_t)obj_offset, p->pack_name); + type = OBJ_BAD; + } + +out: + if (poi_stack != small_poi_stack) + free(poi_stack); + return type; + +unwind: + while (poi_stack_nr) { + obj_offset = poi_stack[--poi_stack_nr]; + type = retry_bad_packed_offset(p, obj_offset); + if (type > OBJ_NONE) + goto out; + } + type = OBJ_BAD; + goto out; +} + +static struct hashmap delta_base_cache; +static size_t delta_base_cached; + +static LIST_HEAD(delta_base_cache_lru); + +struct delta_base_cache_key { + struct packed_git *p; + off_t base_offset; +}; + +struct delta_base_cache_entry { + struct hashmap hash; + struct delta_base_cache_key key; + struct list_head lru; + void *data; + unsigned long size; + enum object_type type; +}; + +static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset) +{ + unsigned int hash; + + hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset; + hash += (hash >> 8) + (hash >> 16); + return hash; +} + +static struct delta_base_cache_entry * +get_delta_base_cache_entry(struct packed_git *p, off_t base_offset) +{ + struct hashmap_entry entry; + struct delta_base_cache_key key; + + if (!delta_base_cache.cmpfn) + return NULL; + + hashmap_entry_init(&entry, pack_entry_hash(p, base_offset)); + key.p = p; + key.base_offset = base_offset; + return hashmap_get(&delta_base_cache, &entry, &key); +} + +static int delta_base_cache_key_eq(const struct delta_base_cache_key *a, + const struct delta_base_cache_key *b) +{ + return a->p == b->p && a->base_offset == b->base_offset; +} + +static int delta_base_cache_hash_cmp(const void *unused_cmp_data, + const void *va, const void *vb, + const void *vkey) +{ + const struct delta_base_cache_entry *a = va, *b = vb; + const struct delta_base_cache_key *key = vkey; + if (key) + return !delta_base_cache_key_eq(&a->key, key); + else + return !delta_base_cache_key_eq(&a->key, &b->key); +} + +static int in_delta_base_cache(struct packed_git *p, off_t base_offset) +{ + return !!get_delta_base_cache_entry(p, base_offset); +} + +/* + * Remove the entry from the cache, but do _not_ free the associated + * entry data. The caller takes ownership of the "data" buffer, and + * should copy out any fields it wants before detaching. + */ +static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent) +{ + hashmap_remove(&delta_base_cache, ent, &ent->key); + list_del(&ent->lru); + delta_base_cached -= ent->size; + free(ent); +} + +static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset, + unsigned long *base_size, enum object_type *type) +{ + struct delta_base_cache_entry *ent; + + ent = get_delta_base_cache_entry(p, base_offset); + if (!ent) + return unpack_entry(p, base_offset, type, base_size); + + if (type) + *type = ent->type; + if (base_size) + *base_size = ent->size; + return xmemdupz(ent->data, ent->size); +} + +static inline void release_delta_base_cache(struct delta_base_cache_entry *ent) +{ + free(ent->data); + detach_delta_base_cache_entry(ent); +} + +void clear_delta_base_cache(void) +{ + struct list_head *lru, *tmp; + list_for_each_safe(lru, tmp, &delta_base_cache_lru) { + struct delta_base_cache_entry *entry = + list_entry(lru, struct delta_base_cache_entry, lru); + release_delta_base_cache(entry); + } +} + +static void add_delta_base_cache(struct packed_git *p, off_t base_offset, + void *base, unsigned long base_size, enum object_type type) +{ + struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent)); + struct list_head *lru, *tmp; + + delta_base_cached += base_size; + + list_for_each_safe(lru, tmp, &delta_base_cache_lru) { + struct delta_base_cache_entry *f = + list_entry(lru, struct delta_base_cache_entry, lru); + if (delta_base_cached <= delta_base_cache_limit) + break; + release_delta_base_cache(f); + } + + ent->key.p = p; + ent->key.base_offset = base_offset; + ent->type = type; + ent->data = base; + ent->size = base_size; + list_add_tail(&ent->lru, &delta_base_cache_lru); + + if (!delta_base_cache.cmpfn) + hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0); + hashmap_entry_init(ent, pack_entry_hash(p, base_offset)); + hashmap_add(&delta_base_cache, ent); +} + +int packed_object_info(struct packed_git *p, off_t obj_offset, + struct object_info *oi) +{ + struct pack_window *w_curs = NULL; + unsigned long size; + off_t curpos = obj_offset; + enum object_type type; + + /* + * We always get the representation type, but only convert it to + * a "real" type later if the caller is interested. + */ + if (oi->contentp) { + *oi->contentp = cache_or_unpack_entry(p, obj_offset, oi->sizep, + &type); + if (!*oi->contentp) + type = OBJ_BAD; + } else { + type = unpack_object_header(p, &w_curs, &curpos, &size); + } + + if (!oi->contentp && oi->sizep) { + if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { + off_t tmp_pos = curpos; + off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos, + type, obj_offset); + if (!base_offset) { + type = OBJ_BAD; + goto out; + } + *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos); + if (*oi->sizep == 0) { + type = OBJ_BAD; + goto out; + } + } else { + *oi->sizep = size; + } + } + + if (oi->disk_sizep) { + struct revindex_entry *revidx = find_pack_revindex(p, obj_offset); + *oi->disk_sizep = revidx[1].offset - obj_offset; + } + + if (oi->typep || oi->type_name) { + enum object_type ptot; + ptot = packed_to_object_type(p, obj_offset, type, &w_curs, + curpos); + if (oi->typep) + *oi->typep = ptot; + if (oi->type_name) { + const char *tn = type_name(ptot); + if (tn) + strbuf_addstr(oi->type_name, tn); + } + if (ptot < 0) { + type = OBJ_BAD; + goto out; + } + } + + if (oi->delta_base_sha1) { + if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) { + const unsigned char *base; + + base = get_delta_base_sha1(p, &w_curs, curpos, + type, obj_offset); + if (!base) { + type = OBJ_BAD; + goto out; + } + + hashcpy(oi->delta_base_sha1, base); + } else + hashclr(oi->delta_base_sha1); + } + + oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED : + OI_PACKED; + +out: + unuse_pack(&w_curs); + return type; +} + +static void *unpack_compressed_entry(struct packed_git *p, + struct pack_window **w_curs, + off_t curpos, + unsigned long size) +{ + int st; + git_zstream stream; + unsigned char *buffer, *in; + + buffer = xmallocz_gently(size); + if (!buffer) + return NULL; + memset(&stream, 0, sizeof(stream)); + stream.next_out = buffer; + stream.avail_out = size + 1; + + git_inflate_init(&stream); + do { + in = use_pack(p, w_curs, curpos, &stream.avail_in); + stream.next_in = in; + st = git_inflate(&stream, Z_FINISH); + if (!stream.avail_out) + break; /* the payload is larger than it should be */ + curpos += stream.next_in - in; + } while (st == Z_OK || st == Z_BUF_ERROR); + git_inflate_end(&stream); + if ((st != Z_STREAM_END) || stream.total_out != size) { + free(buffer); + return NULL; + } + + return buffer; +} + +static void write_pack_access_log(struct packed_git *p, off_t obj_offset) +{ + static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS); + trace_printf_key(&pack_access, "%s %"PRIuMAX"\n", + p->pack_name, (uintmax_t)obj_offset); +} + +int do_check_packed_object_crc; + +#define UNPACK_ENTRY_STACK_PREALLOC 64 +struct unpack_entry_stack_ent { + off_t obj_offset; + off_t curpos; + unsigned long size; +}; + +static void *read_object(const unsigned char *sha1, enum object_type *type, + unsigned long *size) +{ + struct object_info oi = OBJECT_INFO_INIT; + void *content; + oi.typep = type; + oi.sizep = size; + oi.contentp = &content; + + if (sha1_object_info_extended(sha1, &oi, 0) < 0) + return NULL; + return content; +} + +void *unpack_entry(struct packed_git *p, off_t obj_offset, + enum object_type *final_type, unsigned long *final_size) +{ + struct pack_window *w_curs = NULL; + off_t curpos = obj_offset; + void *data = NULL; + unsigned long size; + enum object_type type; + struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC]; + struct unpack_entry_stack_ent *delta_stack = small_delta_stack; + int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC; + int base_from_cache = 0; + + write_pack_access_log(p, obj_offset); + + /* PHASE 1: drill down to the innermost base object */ + for (;;) { + off_t base_offset; + int i; + struct delta_base_cache_entry *ent; + + ent = get_delta_base_cache_entry(p, curpos); + if (ent) { + type = ent->type; + data = ent->data; + size = ent->size; + detach_delta_base_cache_entry(ent); + base_from_cache = 1; + break; + } + + if (do_check_packed_object_crc && p->index_version > 1) { + struct revindex_entry *revidx = find_pack_revindex(p, obj_offset); + off_t len = revidx[1].offset - obj_offset; + if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) { + const unsigned char *sha1 = + nth_packed_object_sha1(p, revidx->nr); + error("bad packed object CRC for %s", + sha1_to_hex(sha1)); + mark_bad_packed_object(p, sha1); + data = NULL; + goto out; + } + } + + type = unpack_object_header(p, &w_curs, &curpos, &size); + if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA) + break; + + base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset); + if (!base_offset) { + error("failed to validate delta base reference " + "at offset %"PRIuMAX" from %s", + (uintmax_t)curpos, p->pack_name); + /* bail to phase 2, in hopes of recovery */ + data = NULL; + break; + } + + /* push object, proceed to base */ + if (delta_stack_nr >= delta_stack_alloc + && delta_stack == small_delta_stack) { + delta_stack_alloc = alloc_nr(delta_stack_nr); + ALLOC_ARRAY(delta_stack, delta_stack_alloc); + memcpy(delta_stack, small_delta_stack, + sizeof(*delta_stack)*delta_stack_nr); + } else { + ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc); + } + i = delta_stack_nr++; + delta_stack[i].obj_offset = obj_offset; + delta_stack[i].curpos = curpos; + delta_stack[i].size = size; + + curpos = obj_offset = base_offset; + } + + /* PHASE 2: handle the base */ + switch (type) { + case OBJ_OFS_DELTA: + case OBJ_REF_DELTA: + if (data) + die("BUG: unpack_entry: left loop at a valid delta"); + break; + case OBJ_COMMIT: + case OBJ_TREE: + case OBJ_BLOB: + case OBJ_TAG: + if (!base_from_cache) + data = unpack_compressed_entry(p, &w_curs, curpos, size); + break; + default: + data = NULL; + error("unknown object type %i at offset %"PRIuMAX" in %s", + type, (uintmax_t)obj_offset, p->pack_name); + } + + /* PHASE 3: apply deltas in order */ + + /* invariants: + * 'data' holds the base data, or NULL if there was corruption + */ + while (delta_stack_nr) { + void *delta_data; + void *base = data; + void *external_base = NULL; + unsigned long delta_size, base_size = size; + int i; + + data = NULL; + + if (base) + add_delta_base_cache(p, obj_offset, base, base_size, type); + + if (!base) { + /* + * We're probably in deep shit, but let's try to fetch + * the required base anyway from another pack or loose. + * This is costly but should happen only in the presence + * of a corrupted pack, and is better than failing outright. + */ + struct revindex_entry *revidx; + const unsigned char *base_sha1; + revidx = find_pack_revindex(p, obj_offset); + if (revidx) { + base_sha1 = nth_packed_object_sha1(p, revidx->nr); + error("failed to read delta base object %s" + " at offset %"PRIuMAX" from %s", + sha1_to_hex(base_sha1), (uintmax_t)obj_offset, + p->pack_name); + mark_bad_packed_object(p, base_sha1); + base = read_object(base_sha1, &type, &base_size); + external_base = base; + } + } + + i = --delta_stack_nr; + obj_offset = delta_stack[i].obj_offset; + curpos = delta_stack[i].curpos; + delta_size = delta_stack[i].size; + + if (!base) + continue; + + delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size); + + if (!delta_data) { + error("failed to unpack compressed delta " + "at offset %"PRIuMAX" from %s", + (uintmax_t)curpos, p->pack_name); + data = NULL; + free(external_base); + continue; + } + + data = patch_delta(base, base_size, + delta_data, delta_size, + &size); + + /* + * We could not apply the delta; warn the user, but keep going. + * Our failure will be noticed either in the next iteration of + * the loop, or if this is the final delta, in the caller when + * we return NULL. Those code paths will take care of making + * a more explicit warning and retrying with another copy of + * the object. + */ + if (!data) + error("failed to apply delta"); + + free(delta_data); + free(external_base); + } + + if (final_type) + *final_type = type; + if (final_size) + *final_size = size; + +out: + unuse_pack(&w_curs); + + if (delta_stack != small_delta_stack) + free(delta_stack); + + return data; +} + +const unsigned char *nth_packed_object_sha1(struct packed_git *p, + uint32_t n) +{ + const unsigned char *index = p->index_data; + if (!index) { + if (open_pack_index(p)) + return NULL; + index = p->index_data; + } + if (n >= p->num_objects) + return NULL; + index += 4 * 256; + if (p->index_version == 1) { + return index + 24 * n + 4; + } else { + index += 8; + return index + 20 * n; + } +} + +const struct object_id *nth_packed_object_oid(struct object_id *oid, + struct packed_git *p, + uint32_t n) +{ + const unsigned char *hash = nth_packed_object_sha1(p, n); + if (!hash) + return NULL; + hashcpy(oid->hash, hash); + return oid; +} + +void check_pack_index_ptr(const struct packed_git *p, const void *vptr) +{ + const unsigned char *ptr = vptr; + const unsigned char *start = p->index_data; + const unsigned char *end = start + p->index_size; + if (ptr < start) + die(_("offset before start of pack index for %s (corrupt index?)"), + p->pack_name); + /* No need to check for underflow; .idx files must be at least 8 bytes */ + if (ptr >= end - 8) + die(_("offset beyond end of pack index for %s (truncated index?)"), + p->pack_name); +} + +off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n) +{ + const unsigned char *index = p->index_data; + index += 4 * 256; + if (p->index_version == 1) { + return ntohl(*((uint32_t *)(index + 24 * n))); + } else { + uint32_t off; + index += 8 + p->num_objects * (20 + 4); + off = ntohl(*((uint32_t *)(index + 4 * n))); + if (!(off & 0x80000000)) + return off; + index += p->num_objects * 4 + (off & 0x7fffffff) * 8; + check_pack_index_ptr(p, index); + return get_be64(index); + } +} + +off_t find_pack_entry_one(const unsigned char *sha1, + struct packed_git *p) +{ + const uint32_t *level1_ofs = p->index_data; + const unsigned char *index = p->index_data; + unsigned stride; + uint32_t result; + + if (!index) { + if (open_pack_index(p)) + return 0; + level1_ofs = p->index_data; + index = p->index_data; + } + if (p->index_version > 1) { + level1_ofs += 2; + index += 8; + } + index += 4 * 256; + if (p->index_version > 1) { + stride = 20; + } else { + stride = 24; + index += 4; + } + + if (bsearch_hash(sha1, level1_ofs, index, stride, &result)) + return nth_packed_object_offset(p, result); + return 0; +} + +int is_pack_valid(struct packed_git *p) +{ + /* An already open pack is known to be valid. */ + if (p->pack_fd != -1) + return 1; + + /* If the pack has one window completely covering the + * file size, the pack is known to be valid even if + * the descriptor is not currently open. + */ + if (p->windows) { + struct pack_window *w = p->windows; + + if (!w->offset && w->len == p->pack_size) + return 1; + } + + /* Force the pack to open to prove its valid. */ + return !open_packed_git(p); +} + +struct packed_git *find_sha1_pack(const unsigned char *sha1, + struct packed_git *packs) +{ + struct packed_git *p; + + for (p = packs; p; p = p->next) { + if (find_pack_entry_one(sha1, p)) + return p; + } + return NULL; + +} + +static int fill_pack_entry(const unsigned char *sha1, + struct pack_entry *e, + struct packed_git *p) +{ + off_t offset; + + if (p->num_bad_objects) { + unsigned i; + for (i = 0; i < p->num_bad_objects; i++) + if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i)) + return 0; + } + + offset = find_pack_entry_one(sha1, p); + if (!offset) + return 0; + + /* + * We are about to tell the caller where they can locate the + * requested object. We better make sure the packfile is + * still here and can be accessed before supplying that + * answer, as it may have been deleted since the index was + * loaded! + */ + if (!is_pack_valid(p)) + return 0; + e->offset = offset; + e->p = p; + hashcpy(e->sha1, sha1); + return 1; +} + +/* + * Iff a pack file contains the object named by sha1, return true and + * store its location to e. + */ +int find_pack_entry(const unsigned char *sha1, struct pack_entry *e) +{ + struct list_head *pos; + + prepare_packed_git(); + if (!packed_git) + return 0; + + list_for_each(pos, &packed_git_mru) { + struct packed_git *p = list_entry(pos, struct packed_git, mru); + if (fill_pack_entry(sha1, e, p)) { + list_move(&p->mru, &packed_git_mru); + return 1; + } + } + return 0; +} + +int has_sha1_pack(const unsigned char *sha1) +{ + struct pack_entry e; + return find_pack_entry(sha1, &e); +} + +int has_pack_index(const unsigned char *sha1) +{ + struct stat st; + if (stat(sha1_pack_index_name(sha1), &st)) + return 0; + return 1; +} + +static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data) +{ + uint32_t i; + int r = 0; + + for (i = 0; i < p->num_objects; i++) { + struct object_id oid; + + if (!nth_packed_object_oid(&oid, p, i)) + return error("unable to get sha1 of object %u in %s", + i, p->pack_name); + + r = cb(&oid, p, i, data); + if (r) + break; + } + return r; +} + +int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags) +{ + struct packed_git *p; + int r = 0; + int pack_errors = 0; + + prepare_packed_git(); + for (p = packed_git; p; p = p->next) { + if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local) + continue; + if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) && + !p->pack_promisor) + continue; + if (open_pack_index(p)) { + pack_errors = 1; + continue; + } + r = for_each_object_in_pack(p, cb, data); + if (r) + break; + } + return r ? r : pack_errors; +} + +static int add_promisor_object(const struct object_id *oid, + struct packed_git *pack, + uint32_t pos, + void *set_) +{ + struct oidset *set = set_; + struct object *obj = parse_object(oid); + if (!obj) + return 1; + + oidset_insert(set, oid); + + /* + * If this is a tree, commit, or tag, the objects it refers + * to are also promisor objects. (Blobs refer to no objects.) + */ + if (obj->type == OBJ_TREE) { + struct tree *tree = (struct tree *)obj; + struct tree_desc desc; + struct name_entry entry; + if (init_tree_desc_gently(&desc, tree->buffer, tree->size)) + /* + * Error messages are given when packs are + * verified, so do not print any here. + */ + return 0; + while (tree_entry_gently(&desc, &entry)) + oidset_insert(set, entry.oid); + } else if (obj->type == OBJ_COMMIT) { + struct commit *commit = (struct commit *) obj; + struct commit_list *parents = commit->parents; + + oidset_insert(set, &commit->tree->object.oid); + for (; parents; parents = parents->next) + oidset_insert(set, &parents->item->object.oid); + } else if (obj->type == OBJ_TAG) { + struct tag *tag = (struct tag *) obj; + oidset_insert(set, &tag->tagged->oid); + } + return 0; +} + +int is_promisor_object(const struct object_id *oid) +{ + static struct oidset promisor_objects; + static int promisor_objects_prepared; + + if (!promisor_objects_prepared) { + if (repository_format_partial_clone) { + for_each_packed_object(add_promisor_object, + &promisor_objects, + FOR_EACH_OBJECT_PROMISOR_ONLY); + } + promisor_objects_prepared = 1; + } + return oidset_contains(&promisor_objects, oid); +} |