Merge branch 'jk/fewer-pack-rescan'
[git/git.git] / sha1_file.c
index fbb73f5..afe4b90 100644 (file)
 #include "list.h"
 #include "mergesort.h"
 #include "quote.h"
+#include "packfile.h"
 
-#define SZ_FMT PRIuMAX
-static inline uintmax_t sz_fmt(size_t s) { return s; }
-
-const unsigned char null_sha1[20];
+const unsigned char null_sha1[GIT_MAX_RAWSZ];
 const struct object_id null_oid;
 const struct object_id empty_tree_oid = {
        EMPTY_TREE_SHA1_BIN_LITERAL
@@ -76,6 +74,18 @@ static struct cached_object *find_cached_object(const unsigned char *sha1)
        return NULL;
 }
 
+
+static enum safe_crlf get_safe_crlf(unsigned flags)
+{
+       if (flags & HASH_RENORMALIZE)
+               return SAFE_CRLF_RENORMALIZE;
+       else if (flags & HASH_WRITE_OBJECT)
+               return safe_crlf;
+       else
+               return SAFE_CRLF_FALSE;
+}
+
+
 int mkdir_in_gitdir(const char *path)
 {
        if (mkdir(path, 0777)) {
@@ -278,28 +288,6 @@ static const char *alt_sha1_path(struct alternate_object_database *alt,
        return buf->buf;
 }
 
- 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");
-}
-
 struct alternate_object_database *alt_odb_list;
 static struct alternate_object_database **alt_odb_tail;
 
@@ -428,6 +416,9 @@ static void link_alt_odb_entries(const char *alt, int sep,
        struct strbuf objdirbuf = STRBUF_INIT;
        struct strbuf entry = STRBUF_INIT;
 
+       if (!alt || !*alt)
+               return;
+
        if (depth > 5) {
                error("%s: ignoring alternate object stores, nesting too deep.",
                                relative_base);
@@ -480,19 +471,19 @@ struct alternate_object_database *alloc_alt_odb(const char *dir)
 
 void add_to_alternates_file(const char *reference)
 {
-       struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+       struct lock_file lock = LOCK_INIT;
        char *alts = git_pathdup("objects/info/alternates");
        FILE *in, *out;
+       int found = 0;
 
-       hold_lock_file_for_update(lock, alts, LOCK_DIE_ON_ERROR);
-       out = fdopen_lock_file(lock, "w");
+       hold_lock_file_for_update(&lock, alts, LOCK_DIE_ON_ERROR);
+       out = fdopen_lock_file(&lock, "w");
        if (!out)
                die_errno("unable to fdopen alternates lockfile");
 
        in = fopen(alts, "r");
        if (in) {
                struct strbuf line = STRBUF_INIT;
-               int found = 0;
 
                while (strbuf_getline(&line, in) != EOF) {
                        if (!strcmp(reference, line.buf)) {
@@ -504,18 +495,15 @@ void add_to_alternates_file(const char *reference)
 
                strbuf_release(&line);
                fclose(in);
-
-               if (found) {
-                       rollback_lock_file(lock);
-                       lock = NULL;
-               }
        }
        else if (errno != ENOENT)
                die_errno("unable to read alternates file");
 
-       if (lock) {
+       if (found) {
+               rollback_lock_file(&lock);
+       } else {
                fprintf_or_die(out, "%s\n", reference);
-               if (commit_lock_file(lock))
+               if (commit_lock_file(&lock))
                        die_errno("unable to move new alternates file into place");
                if (alt_odb_tail)
                        link_alt_odb_entries(reference, '\n', NULL, 0);
@@ -631,7 +619,6 @@ void prepare_alt_odb(void)
                return;
 
        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
-       if (!alt) alt = "";
 
        alt_odb_tail = &alt_odb_list;
        link_alt_odb_entries(alt, PATH_SEP, NULL, 0);
@@ -696,213 +683,6 @@ static int has_loose_object(const unsigned char *sha1)
        return check_and_freshen(sha1, 0);
 }
 
-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;
-
-static struct mru packed_git_mru_storage;
-struct mru *packed_git_mru = &packed_git_mru_storage;
-
-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 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 */
-}
-
 static void mmap_limit_check(size_t length)
 {
        static size_t limit = 0;
@@ -941,1948 +721,360 @@ void *xmmap(void *start, size_t length,
        return ret;
 }
 
-void close_pack_windows(struct packed_git *p)
+/*
+ * With an in-core object data in "map", rehash it to make sure the
+ * object name actually matches "sha1" to detect object corruption.
+ * With "map" == NULL, try reading the object named with "sha1" using
+ * the streaming interface and rehash it to do the same.
+ */
+int check_sha1_signature(const unsigned char *sha1, void *map,
+                        unsigned long size, const char *type)
 {
-       while (p->windows) {
-               struct pack_window *w = p->windows;
+       unsigned char real_sha1[20];
+       enum object_type obj_type;
+       struct git_istream *st;
+       git_SHA_CTX c;
+       char hdr[32];
+       int hdrlen;
 
-               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);
+       if (map) {
+               hash_sha1_file(map, size, type, real_sha1);
+               return hashcmp(sha1, real_sha1) ? -1 : 0;
        }
-}
-
-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;
-}
-
-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);
-}
 
+       st = open_istream(sha1, &obj_type, &size, NULL);
+       if (!st)
+               return -1;
 
-/*
- * 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;
+       /* Generate the header */
+       hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 
-       /*
-        * 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;
+       /* Sha1.. */
+       git_SHA1_Init(&c);
+       git_SHA1_Update(&c, hdr, hdrlen);
+       for (;;) {
+               char buf[1024 * 16];
+               ssize_t readlen = read_istream(st, buf, sizeof(buf));
 
-       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 (readlen < 0) {
+                       close_istream(st);
+                       return -1;
                }
-
-               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;
+               if (!readlen)
+                       break;
+               git_SHA1_Update(&c, buf, readlen);
        }
-
-       /*
-        * Select this pack.
-        */
-       *mru_w = this_mru_w;
-       *lru_p = p;
-       *accept_windows_inuse = has_windows_inuse;
+       git_SHA1_Final(real_sha1, &c);
+       close_istream(st);
+       return hashcmp(sha1, real_sha1) ? -1 : 0;
 }
 
-static int close_one_pack(void)
+int git_open_cloexec(const char *name, int flags)
 {
-       struct packed_git *p, *lru_p = NULL;
-       struct pack_window *mru_w = NULL;
-       int accept_windows_inuse = 1;
+       int fd;
+       static int o_cloexec = O_CLOEXEC;
 
-       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);
+       fd = open(name, flags | o_cloexec);
+       if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
+               /* Try again w/o O_CLOEXEC: the kernel might not support it */
+               o_cloexec &= ~O_CLOEXEC;
+               fd = open(name, flags | o_cloexec);
        }
 
-       if (lru_p)
-               return close_pack_fd(lru_p);
-
-       return 0;
-}
-
-void unuse_pack(struct pack_window **w_cursor)
-{
-       struct pack_window *w = *w_cursor;
-       if (w) {
-               w->inuse_cnt--;
-               *w_cursor = NULL;
-       }
-}
+#if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
+       {
+               static int fd_cloexec = FD_CLOEXEC;
 
-void close_pack_index(struct packed_git *p)
-{
-       if (p->index_data) {
-               munmap((void *)p->index_data, p->index_size);
-               p->index_data = NULL;
+               if (!o_cloexec && 0 <= fd && fd_cloexec) {
+                       /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
+                       int flags = fcntl(fd, F_GETFD);
+                       if (fcntl(fd, F_SETFD, flags | fd_cloexec))
+                               fd_cloexec = 0;
+               }
        }
+#endif
+       return fd;
 }
 
-static unsigned int get_max_fd_limit(void)
+/*
+ * Find "sha1" as a loose object in the local repository or in an alternate.
+ * Returns 0 on success, negative on failure.
+ *
+ * The "path" out-parameter will give the path of the object we found (if any).
+ * Note that it may point to static storage and is only valid until another
+ * call to sha1_file_name(), etc.
+ */
+static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
+                         const char **path)
 {
-#ifdef RLIMIT_NOFILE
-       {
-               struct rlimit lim;
+       struct alternate_object_database *alt;
 
-               if (!getrlimit(RLIMIT_NOFILE, &lim))
-                       return lim.rlim_cur;
-       }
-#endif
+       *path = sha1_file_name(sha1);
+       if (!lstat(*path, st))
+               return 0;
 
-#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.
-                */
+       prepare_alt_odb();
+       errno = ENOENT;
+       for (alt = alt_odb_list; alt; alt = alt->next) {
+               *path = alt_sha1_path(alt, sha1);
+               if (!lstat(*path, st))
+                       return 0;
        }
-#endif
 
-#ifdef OPEN_MAX
-       return OPEN_MAX;
-#else
-       return 1; /* see the caller ;-) */
-#endif
+       return -1;
 }
 
 /*
- * Do not call this directly as this leaks p->pack_fd on error return;
- * call open_packed_git() instead.
+ * Like stat_sha1_file(), but actually open the object and return the
+ * descriptor. See the caveats on the "path" parameter above.
  */
-static int open_packed_git_1(struct packed_git *p)
+static int open_sha1_file(const unsigned char *sha1, const char **path)
 {
-       struct stat st;
-       struct pack_header hdr;
-       unsigned char sha1[20];
-       unsigned char *idx_sha1;
-       long fd_flag;
-
-       if (!p->index_data && open_pack_index(p))
-               return error("packfile %s index unavailable", p->pack_name);
+       int fd;
+       struct alternate_object_database *alt;
+       int most_interesting_errno;
 
-       if (!pack_max_fds) {
-               unsigned int max_fds = get_max_fd_limit();
+       *path = sha1_file_name(sha1);
+       fd = git_open(*path);
+       if (fd >= 0)
+               return fd;
+       most_interesting_errno = errno;
 
-               /* Save 3 for stdin/stdout/stderr, 22 for work */
-               if (25 < max_fds)
-                       pack_max_fds = max_fds - 25;
-               else
-                       pack_max_fds = 1;
+       prepare_alt_odb();
+       for (alt = alt_odb_list; alt; alt = alt->next) {
+               *path = alt_sha1_path(alt, sha1);
+               fd = git_open(*path);
+               if (fd >= 0)
+                       return fd;
+               if (most_interesting_errno == ENOENT)
+                       most_interesting_errno = errno;
        }
-
-       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. */
-       if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != 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);
-       if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != 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);
+       errno = most_interesting_errno;
        return -1;
 }
 
-static int in_window(struct pack_window *win, off_t offset)
+/*
+ * Map the loose object at "path" if it is not NULL, or the path found by
+ * searching for a loose object named "sha1".
+ */
+static void *map_sha1_file_1(const char *path,
+                            const unsigned char *sha1,
+                            unsigned long *size)
 {
-       /* 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;
-}
-
-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;
-}
-
-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;
-
-       /*
-        * ".pack" is long enough to hold any suffix we're adding (and
-        * the use xsnprintf double-checks that)
-        */
-       alloc = st_add3(path_len, strlen(".pack"), 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, ".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;
-}
-
-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;
-}
-
-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"))
-                       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;
-
-       mru_clear(packed_git_mru);
-       for (p = packed_git; p; p = p->next)
-               mru_append(packed_git_mru, p);
-}
-
-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();
-}
-
-static 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++;
-}
-
-static 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;
-}
-
-/*
- * With an in-core object data in "map", rehash it to make sure the
- * object name actually matches "sha1" to detect object corruption.
- * With "map" == NULL, try reading the object named with "sha1" using
- * the streaming interface and rehash it to do the same.
- */
-int check_sha1_signature(const unsigned char *sha1, void *map,
-                        unsigned long size, const char *type)
-{
-       unsigned char real_sha1[20];
-       enum object_type obj_type;
-       struct git_istream *st;
-       git_SHA_CTX c;
-       char hdr[32];
-       int hdrlen;
-
-       if (map) {
-               hash_sha1_file(map, size, type, real_sha1);
-               return hashcmp(sha1, real_sha1) ? -1 : 0;
-       }
-
-       st = open_istream(sha1, &obj_type, &size, NULL);
-       if (!st)
-               return -1;
-
-       /* Generate the header */
-       hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
-
-       /* Sha1.. */
-       git_SHA1_Init(&c);
-       git_SHA1_Update(&c, hdr, hdrlen);
-       for (;;) {
-               char buf[1024 * 16];
-               ssize_t readlen = read_istream(st, buf, sizeof(buf));
-
-               if (readlen < 0) {
-                       close_istream(st);
-                       return -1;
-               }
-               if (!readlen)
-                       break;
-               git_SHA1_Update(&c, buf, readlen);
-       }
-       git_SHA1_Final(real_sha1, &c);
-       close_istream(st);
-       return hashcmp(sha1, real_sha1) ? -1 : 0;
-}
-
-int git_open_cloexec(const char *name, int flags)
-{
-       int fd;
-       static int o_cloexec = O_CLOEXEC;
-
-       fd = open(name, flags | o_cloexec);
-       if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
-               /* Try again w/o O_CLOEXEC: the kernel might not support it */
-               o_cloexec &= ~O_CLOEXEC;
-               fd = open(name, flags | o_cloexec);
-       }
-
-#if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
-       {
-               static int fd_cloexec = FD_CLOEXEC;
-
-               if (!o_cloexec && 0 <= fd && fd_cloexec) {
-                       /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
-                       int flags = fcntl(fd, F_GETFD);
-                       if (fcntl(fd, F_SETFD, flags | fd_cloexec))
-                               fd_cloexec = 0;
-               }
-       }
-#endif
-       return fd;
-}
-
-/*
- * Find "sha1" as a loose object in the local repository or in an alternate.
- * Returns 0 on success, negative on failure.
- *
- * The "path" out-parameter will give the path of the object we found (if any).
- * Note that it may point to static storage and is only valid until another
- * call to sha1_file_name(), etc.
- */
-static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
-                         const char **path)
-{
-       struct alternate_object_database *alt;
-
-       *path = sha1_file_name(sha1);
-       if (!lstat(*path, st))
-               return 0;
-
-       prepare_alt_odb();
-       errno = ENOENT;
-       for (alt = alt_odb_list; alt; alt = alt->next) {
-               *path = alt_sha1_path(alt, sha1);
-               if (!lstat(*path, st))
-                       return 0;
-       }
-
-       return -1;
-}
-
-/*
- * Like stat_sha1_file(), but actually open the object and return the
- * descriptor. See the caveats on the "path" parameter above.
- */
-static int open_sha1_file(const unsigned char *sha1, const char **path)
-{
-       int fd;
-       struct alternate_object_database *alt;
-       int most_interesting_errno;
-
-       *path = sha1_file_name(sha1);
-       fd = git_open(*path);
-       if (fd >= 0)
-               return fd;
-       most_interesting_errno = errno;
-
-       prepare_alt_odb();
-       for (alt = alt_odb_list; alt; alt = alt->next) {
-               *path = alt_sha1_path(alt, sha1);
-               fd = git_open(*path);
-               if (fd >= 0)
-                       return fd;
-               if (most_interesting_errno == ENOENT)
-                       most_interesting_errno = errno;
-       }
-       errno = most_interesting_errno;
-       return -1;
-}
-
-/*
- * Map the loose object at "path" if it is not NULL, or the path found by
- * searching for a loose object named "sha1".
- */
-static void *map_sha1_file_1(const char *path,
-                            const unsigned char *sha1,
-                            unsigned long *size)
-{
-       void *map;
-       int fd;
-
-       if (path)
-               fd = git_open(path);
-       else
-               fd = open_sha1_file(sha1, &path);
-       map = NULL;
-       if (fd >= 0) {
-               struct stat st;
-
-               if (!fstat(fd, &st)) {
-                       *size = xsize_t(st.st_size);
-                       if (!*size) {
-                               /* mmap() is forbidden on empty files */
-                               error("object file %s is empty", path);
-                               return NULL;
-                       }
-                       map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
-               }
-               close(fd);
-       }
-       return map;
-}
-
-void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
-{
-       return map_sha1_file_1(NULL, sha1, size);
-}
-
-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;
-}
-
-static int unpack_sha1_short_header(git_zstream *stream,
-                                   unsigned char *map, unsigned long mapsize,
-                                   void *buffer, unsigned long bufsiz)
-{
-       /* Get the data stream */
-       memset(stream, 0, sizeof(*stream));
-       stream->next_in = map;
-       stream->avail_in = mapsize;
-       stream->next_out = buffer;
-       stream->avail_out = bufsiz;
-
-       git_inflate_init(stream);
-       return git_inflate(stream, 0);
-}
-
-int unpack_sha1_header(git_zstream *stream,
-                      unsigned char *map, unsigned long mapsize,
-                      void *buffer, unsigned long bufsiz)
-{
-       int status = unpack_sha1_short_header(stream, map, mapsize,
-                                             buffer, bufsiz);
-
-       if (status < Z_OK)
-               return status;
-
-       /* Make sure we have the terminating NUL */
-       if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
-               return -1;
-       return 0;
-}
-
-static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
-                                       unsigned long mapsize, void *buffer,
-                                       unsigned long bufsiz, struct strbuf *header)
-{
-       int status;
-
-       status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
-       if (status < Z_OK)
-               return -1;
-
-       /*
-        * Check if entire header is unpacked in the first iteration.
-        */
-       if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
-               return 0;
-
-       /*
-        * buffer[0..bufsiz] was not large enough.  Copy the partial
-        * result out to header, and then append the result of further
-        * reading the stream.
-        */
-       strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
-       stream->next_out = buffer;
-       stream->avail_out = bufsiz;
-
-       do {
-               status = git_inflate(stream, 0);
-               strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
-               if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
-                       return 0;
-               stream->next_out = buffer;
-               stream->avail_out = bufsiz;
-       } while (status != Z_STREAM_END);
-       return -1;
-}
-
-static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
-{
-       int bytes = strlen(buffer) + 1;
-       unsigned char *buf = xmallocz(size);
-       unsigned long n;
-       int status = Z_OK;
-
-       n = stream->total_out - bytes;
-       if (n > size)
-               n = size;
-       memcpy(buf, (char *) buffer + bytes, n);
-       bytes = n;
-       if (bytes <= size) {
-               /*
-                * The above condition must be (bytes <= size), not
-                * (bytes < size).  In other words, even though we
-                * expect no more output and set avail_out to zero,
-                * the input zlib stream may have bytes that express
-                * "this concludes the stream", and we *do* want to
-                * eat that input.
-                *
-                * Otherwise we would not be able to test that we
-                * consumed all the input to reach the expected size;
-                * we also want to check that zlib tells us that all
-                * went well with status == Z_STREAM_END at the end.
-                */
-               stream->next_out = buf + bytes;
-               stream->avail_out = size - bytes;
-               while (status == Z_OK)
-                       status = git_inflate(stream, Z_FINISH);
-       }
-       if (status == Z_STREAM_END && !stream->avail_in) {
-               git_inflate_end(stream);
-               return buf;
-       }
-
-       if (status < 0)
-               error("corrupt loose object '%s'", sha1_to_hex(sha1));
-       else if (stream->avail_in)
-               error("garbage at end of loose object '%s'",
-                     sha1_to_hex(sha1));
-       free(buf);
-       return NULL;
-}
-
-/*
- * We used to just use "sscanf()", but that's actually way
- * too permissive for what we want to check. So do an anal
- * object header parse by hand.
- */
-static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
-                              unsigned int flags)
-{
-       const char *type_buf = hdr;
-       unsigned long size;
-       int type, type_len = 0;
-
-       /*
-        * The type can be of any size but is followed by
-        * a space.
-        */
-       for (;;) {
-               char c = *hdr++;
-               if (!c)
-                       return -1;
-               if (c == ' ')
-                       break;
-               type_len++;
-       }
-
-       type = type_from_string_gently(type_buf, type_len, 1);
-       if (oi->typename)
-               strbuf_add(oi->typename, type_buf, type_len);
-       /*
-        * Set type to 0 if its an unknown object and
-        * we're obtaining the type using '--allow-unknown-type'
-        * option.
-        */
-       if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
-               type = 0;
-       else if (type < 0)
-               die("invalid object type");
-       if (oi->typep)
-               *oi->typep = type;
-
-       /*
-        * The length must follow immediately, and be in canonical
-        * decimal format (ie "010" is not valid).
-        */
-       size = *hdr++ - '0';
-       if (size > 9)
-               return -1;
-       if (size) {
-               for (;;) {
-                       unsigned long c = *hdr - '0';
-                       if (c > 9)
-                               break;
-                       hdr++;
-                       size = size * 10 + c;
-               }
-       }
-
-       if (oi->sizep)
-               *oi->sizep = size;
-
-       /*
-        * The length must be followed by a zero byte
-        */
-       return *hdr ? -1 : type;
-}
-
-int parse_sha1_header(const char *hdr, unsigned long *sizep)
-{
-       struct object_info oi = OBJECT_INFO_INIT;
-
-       oi.sizep = sizep;
-       return parse_sha1_header_extended(hdr, &oi, 0);
-}
-
-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));
-}
-
-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;
-}
-
-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;
-}
-
-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;
-}
+       void *map;
+       int fd;
 
-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);
+       if (path)
+               fd = git_open(path);
        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->typename) {
-               enum object_type ptot;
-               ptot = packed_to_object_type(p, obj_offset, type, &w_curs,
-                                            curpos);
-               if (oi->typep)
-                       *oi->typep = ptot;
-               if (oi->typename) {
-                       const char *tn = typename(ptot);
-                       if (tn)
-                               strbuf_addstr(oi->typename, 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);
-       }
-
-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 *read_object(const unsigned char *sha1, enum object_type *type,
-                        unsigned long *size);
-
-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;
-};
-
-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;
-}
+               fd = open_sha1_file(sha1, &path);
+       map = NULL;
+       if (fd >= 0) {
+               struct stat st;
 
-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;
+               if (!fstat(fd, &st)) {
+                       *size = xsize_t(st.st_size);
+                       if (!*size) {
+                               /* mmap() is forbidden on empty files */
+                               error("object file %s is empty", path);
+                               return NULL;
+                       }
+                       map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
+               }
+               close(fd);
        }
+       return map;
 }
 
-const struct object_id *nth_packed_object_oid(struct object_id *oid,
-                                             struct packed_git *p,
-                                             uint32_t n)
+void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
-       const unsigned char *hash = nth_packed_object_sha1(p, n);
-       if (!hash)
-               return NULL;
-       hashcpy(oid->hash, hash);
-       return oid;
+       return map_sha1_file_1(NULL, sha1, size);
 }
 
-void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
+static int unpack_sha1_short_header(git_zstream *stream,
+                                   unsigned char *map, unsigned long mapsize,
+                                   void *buffer, unsigned long bufsiz)
 {
-       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);
-}
+       /* Get the data stream */
+       memset(stream, 0, sizeof(*stream));
+       stream->next_in = map;
+       stream->avail_in = mapsize;
+       stream->next_out = buffer;
+       stream->avail_out = bufsiz;
 
-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 (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
-                                  ntohl(*((uint32_t *)(index + 4)));
-       }
+       git_inflate_init(stream);
+       return git_inflate(stream, 0);
 }
 
-off_t find_pack_entry_one(const unsigned char *sha1,
-                                 struct packed_git *p)
+int unpack_sha1_header(git_zstream *stream,
+                      unsigned char *map, unsigned long mapsize,
+                      void *buffer, unsigned long bufsiz)
 {
-       const uint32_t *level1_ofs = p->index_data;
-       const unsigned char *index = p->index_data;
-       unsigned hi, lo, stride;
-       static int debug_lookup = -1;
-
-       if (debug_lookup < 0)
-               debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
+       int status = unpack_sha1_short_header(stream, map, mapsize,
+                                             buffer, bufsiz);
 
-       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;
-       hi = ntohl(level1_ofs[*sha1]);
-       lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
-       if (p->index_version > 1) {
-               stride = 20;
-       } else {
-               stride = 24;
-               index += 4;
-       }
+       if (status < Z_OK)
+               return status;
 
-       if (debug_lookup)
-               printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
-                      sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
-
-       while (lo < hi) {
-               unsigned mi = (lo + hi) / 2;
-               int cmp = hashcmp(index + mi * stride, sha1);
-
-               if (debug_lookup)
-                       printf("lo %u hi %u rg %u mi %u\n",
-                              lo, hi, hi - lo, mi);
-               if (!cmp)
-                       return nth_packed_object_offset(p, mi);
-               if (cmp > 0)
-                       hi = mi;
-               else
-                       lo = mi+1;
-       }
+       /* Make sure we have the terminating NUL */
+       if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
+               return -1;
        return 0;
 }
 
-int is_pack_valid(struct packed_git *p)
+static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
+                                       unsigned long mapsize, void *buffer,
+                                       unsigned long bufsiz, struct strbuf *header)
 {
-       /* An already open pack is known to be valid. */
-       if (p->pack_fd != -1)
-               return 1;
+       int status;
+
+       status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
+       if (status < Z_OK)
+               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.
+       /*
+        * Check if entire header is unpacked in the first iteration.
         */
-       if (p->windows) {
-               struct pack_window *w = p->windows;
+       if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
+               return 0;
 
-               if (!w->offset && w->len == p->pack_size)
-                       return 1;
-       }
+       /*
+        * buffer[0..bufsiz] was not large enough.  Copy the partial
+        * result out to header, and then append the result of further
+        * reading the stream.
+        */
+       strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
+       stream->next_out = buffer;
+       stream->avail_out = bufsiz;
 
-       /* Force the pack to open to prove its valid. */
-       return !open_packed_git(p);
+       do {
+               status = git_inflate(stream, 0);
+               strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
+               if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
+                       return 0;
+               stream->next_out = buffer;
+               stream->avail_out = bufsiz;
+       } while (status != Z_STREAM_END);
+       return -1;
 }
 
-static int fill_pack_entry(const unsigned char *sha1,
-                          struct pack_entry *e,
-                          struct packed_git *p)
+static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
 {
-       off_t offset;
+       int bytes = strlen(buffer) + 1;
+       unsigned char *buf = xmallocz(size);
+       unsigned long n;
+       int status = Z_OK;
 
-       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;
+       n = stream->total_out - bytes;
+       if (n > size)
+               n = size;
+       memcpy(buf, (char *) buffer + bytes, n);
+       bytes = n;
+       if (bytes <= size) {
+               /*
+                * The above condition must be (bytes <= size), not
+                * (bytes < size).  In other words, even though we
+                * expect no more output and set avail_out to zero,
+                * the input zlib stream may have bytes that express
+                * "this concludes the stream", and we *do* want to
+                * eat that input.
+                *
+                * Otherwise we would not be able to test that we
+                * consumed all the input to reach the expected size;
+                * we also want to check that zlib tells us that all
+                * went well with status == Z_STREAM_END at the end.
+                */
+               stream->next_out = buf + bytes;
+               stream->avail_out = size - bytes;
+               while (status == Z_OK)
+                       status = git_inflate(stream, Z_FINISH);
+       }
+       if (status == Z_STREAM_END && !stream->avail_in) {
+               git_inflate_end(stream);
+               return buf;
        }
 
-       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;
+       if (status < 0)
+               error("corrupt loose object '%s'", sha1_to_hex(sha1));
+       else if (stream->avail_in)
+               error("garbage at end of loose object '%s'",
+                     sha1_to_hex(sha1));
+       free(buf);
+       return NULL;
 }
 
 /*
- * Iff a pack file contains the object named by sha1, return true and
- * store its location to e.
+ * We used to just use "sscanf()", but that's actually way
+ * too permissive for what we want to check. So do an anal
+ * object header parse by hand.
  */
-static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
+static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
+                              unsigned int flags)
 {
-       struct mru_entry *p;
+       const char *type_buf = hdr;
+       unsigned long size;
+       int type, type_len = 0;
 
-       prepare_packed_git();
-       if (!packed_git)
-               return 0;
+       /*
+        * The type can be of any size but is followed by
+        * a space.
+        */
+       for (;;) {
+               char c = *hdr++;
+               if (!c)
+                       return -1;
+               if (c == ' ')
+                       break;
+               type_len++;
+       }
 
-       for (p = packed_git_mru->head; p; p = p->next) {
-               if (fill_pack_entry(sha1, e, p->item)) {
-                       mru_mark(packed_git_mru, p);
-                       return 1;
+       type = type_from_string_gently(type_buf, type_len, 1);
+       if (oi->typename)
+               strbuf_add(oi->typename, type_buf, type_len);
+       /*
+        * Set type to 0 if its an unknown object and
+        * we're obtaining the type using '--allow-unknown-type'
+        * option.
+        */
+       if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
+               type = 0;
+       else if (type < 0)
+               die("invalid object type");
+       if (oi->typep)
+               *oi->typep = type;
+
+       /*
+        * The length must follow immediately, and be in canonical
+        * decimal format (ie "010" is not valid).
+        */
+       size = *hdr++ - '0';
+       if (size > 9)
+               return -1;
+       if (size) {
+               for (;;) {
+                       unsigned long c = *hdr - '0';
+                       if (c > 9)
+                               break;
+                       hdr++;
+                       size = size * 10 + c;
                }
        }
-       return 0;
+
+       if (oi->sizep)
+               *oi->sizep = size;
+
+       /*
+        * The length must be followed by a zero byte
+        */
+       return *hdr ? -1 : type;
 }
 
-struct packed_git *find_sha1_pack(const unsigned char *sha1,
-                                 struct packed_git *packs)
+int parse_sha1_header(const char *hdr, unsigned long *sizep)
 {
-       struct packed_git *p;
-
-       for (p = packs; p; p = p->next) {
-               if (find_pack_entry_one(sha1, p))
-                       return p;
-       }
-       return NULL;
+       struct object_info oi = OBJECT_INFO_INIT;
 
+       oi.sizep = sizep;
+       return parse_sha1_header_extended(hdr, &oi, 0);
 }
 
 static int sha1_loose_object_info(const unsigned char *sha1,
@@ -2959,6 +1151,7 @@ static int sha1_loose_object_info(const unsigned char *sha1,
        if (oi->sizep == &size_scratch)
                oi->sizep = NULL;
        strbuf_release(&hdrbuf);
+       oi->whence = OI_LOOSE;
        return (status < 0) ? status : 0;
 }
 
@@ -2999,10 +1192,8 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
 
        if (!find_pack_entry(real, &e)) {
                /* Most likely it's a loose object. */
-               if (!sha1_loose_object_info(real, oi, flags)) {
-                       oi->whence = OI_LOOSE;
+               if (!sha1_loose_object_info(real, oi, flags))
                        return 0;
-               }
 
                /* Not a loose object; someone else may have just packed it. */
                if (flags & OBJECT_INFO_QUICK) {
@@ -3025,10 +1216,7 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
        if (rtype < 0) {
                mark_bad_packed_object(e.p, real);
                return sha1_object_info_extended(real, oi, 0);
-       } else if (in_delta_base_cache(e.p, e.offset)) {
-               oi->whence = OI_DBCACHED;
-       } else {
-               oi->whence = OI_PACKED;
+       } else if (oi->whence == OI_PACKED) {
                oi->u.packed.offset = e.offset;
                oi->u.packed.pack = e.p;
                oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
@@ -3052,28 +1240,18 @@ int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
        return type;
 }
 
-static void *read_packed_sha1(const unsigned char *sha1,
-                             enum object_type *type, unsigned long *size)
+static void *read_object(const unsigned char *sha1, enum object_type *type,
+                        unsigned long *size)
 {
-       struct pack_entry e;
-       void *data;
+       struct object_info oi = OBJECT_INFO_INIT;
+       void *content;
+       oi.typep = type;
+       oi.sizep = size;
+       oi.contentp = &content;
 
-       if (!find_pack_entry(sha1, &e))
+       if (sha1_object_info_extended(sha1, &oi, 0) < 0)
                return NULL;
-       data = cache_or_unpack_entry(e.p, e.offset, size, type);
-       if (!data) {
-               /*
-                * We're probably in deep shit, but let's try to fetch
-                * the required object anyway from another pack or loose.
-                * This should happen only in the presence of a corrupted
-                * pack, and is better than failing outright.
-                */
-               error("failed to read object %s at offset %"PRIuMAX" from %s",
-                     sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
-               mark_bad_packed_object(e.p, sha1);
-               data = read_object(sha1, type, size);
-       }
-       return data;
+       return content;
 }
 
 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
@@ -3094,20 +1272,6 @@ int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
        return 0;
 }
 
-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;
-}
-
 /*
  * This function dies on corrupt objects; the callers who want to
  * deal with them should arrange to call read_object() and give error
@@ -3426,7 +1590,7 @@ int write_sha1_file(const void *buf, unsigned long len, const char *type, unsign
 }
 
 int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
-                            unsigned char *sha1, unsigned flags)
+                            struct object_id *oid, unsigned flags)
 {
        char *header;
        int hdrlen, status = 0;
@@ -3434,13 +1598,13 @@ int hash_sha1_file_literally(const void *buf, unsigned long len, const char *typ
        /* type string, SP, %lu of the length plus NUL must fit this */
        hdrlen = strlen(type) + 32;
        header = xmalloc(hdrlen);
-       write_sha1_file_prepare(buf, len, type, sha1, header, &hdrlen);
+       write_sha1_file_prepare(buf, len, type, oid->hash, header, &hdrlen);
 
        if (!(flags & HASH_WRITE_OBJECT))
                goto cleanup;
-       if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
+       if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
                goto cleanup;
-       status = write_loose_object(sha1, header, hdrlen, buf, len, 0);
+       status = write_loose_object(oid->hash, header, hdrlen, buf, len, 0);
 
 cleanup:
        free(header);
@@ -3458,7 +1622,7 @@ int force_object_loose(const unsigned char *sha1, time_t mtime)
 
        if (has_loose_object(sha1))
                return 0;
-       buf = read_packed_sha1(sha1, &type, &len);
+       buf = read_object(sha1, &type, &len);
        if (!buf)
                return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
@@ -3468,20 +1632,6 @@ int force_object_loose(const unsigned char *sha1, time_t mtime)
        return ret;
 }
 
-int has_pack_index(const unsigned char *sha1)
-{
-       struct stat st;
-       if (stat(sha1_pack_index_name(sha1), &st))
-               return 0;
-       return 1;
-}
-
-int has_sha1_pack(const unsigned char *sha1)
-{
-       struct pack_entry e;
-       return find_pack_entry(sha1, &e);
-}
-
 int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
 {
        if (!startup_info->have_repository)
@@ -3528,7 +1678,7 @@ static void check_tag(const void *buf, size_t size)
                die("corrupt tag");
 }
 
-static int index_mem(unsigned char *sha1, void *buf, size_t size,
+static int index_mem(struct object_id *oid, void *buf, size_t size,
                     enum object_type type,
                     const char *path, unsigned flags)
 {
@@ -3544,7 +1694,7 @@ static int index_mem(unsigned char *sha1, void *buf, size_t size,
        if ((type == OBJ_BLOB) && path) {
                struct strbuf nbuf = STRBUF_INIT;
                if (convert_to_git(&the_index, path, buf, size, &nbuf,
-                                  write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
+                                  get_safe_crlf(flags))) {
                        buf = strbuf_detach(&nbuf, &size);
                        re_allocated = 1;
                }
@@ -3559,15 +1709,15 @@ static int index_mem(unsigned char *sha1, void *buf, size_t size,
        }
 
        if (write_object)
-               ret = write_sha1_file(buf, size, typename(type), sha1);
+               ret = write_sha1_file(buf, size, typename(type), oid->hash);
        else
-               ret = hash_sha1_file(buf, size, typename(type), sha1);
+               ret = hash_sha1_file(buf, size, typename(type), oid->hash);
        if (re_allocated)
                free(buf);
        return ret;
 }
 
-static int index_stream_convert_blob(unsigned char *sha1, int fd,
+static int index_stream_convert_blob(struct object_id *oid, int fd,
                                     const char *path, unsigned flags)
 {
        int ret;
@@ -3578,26 +1728,26 @@ static int index_stream_convert_blob(unsigned char *sha1, int fd,
        assert(would_convert_to_git_filter_fd(path));
 
        convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
-                                write_object ? safe_crlf : SAFE_CRLF_FALSE);
+                                get_safe_crlf(flags));
 
        if (write_object)
                ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
-                                     sha1);
+                                     oid->hash);
        else
                ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
-                                    sha1);
+                                    oid->hash);
        strbuf_release(&sbuf);
        return ret;
 }
 
-static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
+static int index_pipe(struct object_id *oid, int fd, enum object_type type,
                      const char *path, unsigned flags)
 {
        struct strbuf sbuf = STRBUF_INIT;
        int ret;
 
        if (strbuf_read(&sbuf, fd, 4096) >= 0)
-               ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
+               ret = index_mem(oid, sbuf.buf, sbuf.len, type, path, flags);
        else
                ret = -1;
        strbuf_release(&sbuf);
@@ -3606,24 +1756,29 @@ static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
 
 #define SMALL_FILE_SIZE (32*1024)
 
-static int index_core(unsigned char *sha1, int fd, size_t size,
+static int index_core(struct object_id *oid, int fd, size_t size,
                      enum object_type type, const char *path,
                      unsigned flags)
 {
        int ret;
 
        if (!size) {
-               ret = index_mem(sha1, "", size, type, path, flags);
+               ret = index_mem(oid, "", size, type, path, flags);
        } else if (size <= SMALL_FILE_SIZE) {
                char *buf = xmalloc(size);
-               if (size == read_in_full(fd, buf, size))
-                       ret = index_mem(sha1, buf, size, type, path, flags);
+               ssize_t read_result = read_in_full(fd, buf, size);
+               if (read_result < 0)
+                       ret = error_errno("read error while indexing %s",
+                                         path ? path : "<unknown>");
+               else if (read_result != size)
+                       ret = error("short read while indexing %s",
+                                   path ? path : "<unknown>");
                else
-                       ret = error_errno("short read");
+                       ret = index_mem(oid, buf, size, type, path, flags);
                free(buf);
        } else {
                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
-               ret = index_mem(sha1, buf, size, type, path, flags);
+               ret = index_mem(oid, buf, size, type, path, flags);
                munmap(buf, size);
        }
        return ret;
@@ -3644,14 +1799,14 @@ static int index_core(unsigned char *sha1, int fd, size_t size,
  * binary blobs, they generally do not want to get any conversion, and
  * callers should avoid this code path when filters are requested.
  */
-static int index_stream(unsigned char *sha1, int fd, size_t size,
+static int index_stream(struct object_id *oid, int fd, size_t size,
                        enum object_type type, const char *path,
                        unsigned flags)
 {
-       return index_bulk_checkin(sha1, fd, size, type, path, flags);
+       return index_bulk_checkin(oid->hash, fd, size, type, path, flags);
 }
 
-int index_fd(unsigned char *sha1, int fd, struct stat *st,
+int index_fd(struct object_id *oid, int fd, struct stat *st,
             enum object_type type, const char *path, unsigned flags)
 {
        int ret;
@@ -3661,31 +1816,32 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st,
         * die() for large files.
         */
        if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
-               ret = index_stream_convert_blob(sha1, fd, path, flags);
+               ret = index_stream_convert_blob(oid, fd, path, flags);
        else if (!S_ISREG(st->st_mode))
-               ret = index_pipe(sha1, fd, type, path, flags);
+               ret = index_pipe(oid, fd, type, path, flags);
        else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
                 (path && would_convert_to_git(&the_index, path)))
-               ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
+               ret = index_core(oid, fd, xsize_t(st->st_size), type, path,
                                 flags);
        else
-               ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
+               ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
                                   flags);
        close(fd);
        return ret;
 }
 
-int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
+int index_path(struct object_id *oid, const char *path, struct stat *st, unsigned flags)
 {
        int fd;
        struct strbuf sb = STRBUF_INIT;
+       int rc = 0;
 
        switch (st->st_mode & S_IFMT) {
        case S_IFREG:
                fd = open(path, O_RDONLY);
                if (fd < 0)
                        return error_errno("open(\"%s\")", path);
-               if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
+               if (index_fd(oid, fd, st, OBJ_BLOB, path, flags) < 0)
                        return error("%s: failed to insert into database",
                                     path);
                break;
@@ -3693,18 +1849,17 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned
                if (strbuf_readlink(&sb, path, st->st_size))
                        return error_errno("readlink(\"%s\")", path);
                if (!(flags & HASH_WRITE_OBJECT))
-                       hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
-               else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
-                       return error("%s: failed to insert into database",
-                                    path);
+                       hash_sha1_file(sb.buf, sb.len, blob_type, oid->hash);
+               else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
+                       rc = error("%s: failed to insert into database", path);
                strbuf_release(&sb);
                break;
        case S_IFDIR:
-               return resolve_gitlink_ref(path, "HEAD", sha1);
+               return resolve_gitlink_ref(path, "HEAD", oid);
        default:
                return error("%s: unsupported file type", path);
        }
-       return 0;
+       return rc;
 }
 
 int read_pack_header(int fd, struct pack_header *header)
@@ -3743,6 +1898,7 @@ int for_each_file_in_obj_subdir(unsigned int subdir_nr,
        DIR *dir;
        struct dirent *de;
        int r = 0;
+       struct object_id oid;
 
        if (subdir_nr > 0xff)
                BUG("invalid loose object subdirectory: %x", subdir_nr);
@@ -3760,6 +1916,8 @@ int for_each_file_in_obj_subdir(unsigned int subdir_nr,
                return r;
        }
 
+       oid.hash[0] = subdir_nr;
+
        while ((de = readdir(dir))) {
                if (is_dot_or_dotdot(de->d_name))
                        continue;
@@ -3767,20 +1925,15 @@ int for_each_file_in_obj_subdir(unsigned int subdir_nr,
                strbuf_setlen(path, baselen);
                strbuf_addf(path, "/%s", de->d_name);
 
-               if (strlen(de->d_name) == GIT_SHA1_HEXSZ - 2)  {
-                       char hex[GIT_MAX_HEXSZ+1];
-                       struct object_id oid;
-
-                       xsnprintf(hex, sizeof(hex), "%02x%s",
-                                 subdir_nr, de->d_name);
-                       if (!get_oid_hex(hex, &oid)) {
-                               if (obj_cb) {
-                                       r = obj_cb(&oid, path->buf, data);
-                                       if (r)
-                                               break;
-                               }
-                               continue;
+               if (strlen(de->d_name) == GIT_SHA1_HEXSZ - 2 &&
+                   !hex_to_bytes(oid.hash + 1, de->d_name,
+                                 GIT_SHA1_RAWSZ - 1)) {
+                       if (obj_cb) {
+                               r = obj_cb(&oid, path->buf, data);
+                               if (r)
+                                       break;
                        }
+                       continue;
                }
 
                if (cruft_cb) {
@@ -3874,46 +2027,6 @@ int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
        return foreach_alt_odb(loose_from_alt_odb, &alt);
 }
 
-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 (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 check_stream_sha1(git_zstream *stream,
                             const char *hdr,
                             unsigned long size,