#include "git-compat-util.h"

#include "environment.h"

#include "gettext.h"

#include "hex.h"

#include "pack.h"

#include "csum-file.h"

#include "remote.h"

#include "chunk-format.h"

#include "object-file.h"

#include "pack-mtimes.h"

#include "pack-objects.h"

#include "pack-revindex.h"

#include "path.h"

#include "repository.h"

#include "strbuf.h"

void reset_pack_idx_option(struct pack_idx_option *opts)

{

  memset(opts, 0, sizeof(*opts));

  opts->version = 2;

  opts->off32_limit = 0x7fffffff;

  opts->delta_base_cache_limit = DEFAULT_DELTA_BASE_CACHE_LIMIT;

}

static int sha1_compare(const void *_a, const void *_b)

{

  struct pack_idx_entry *a = *(struct pack_idx_entry **)_a;

  struct pack_idx_entry *b = *(struct pack_idx_entry **)_b;

  return oidcmp(&a->oid, &b->oid);

}

static int cmp_uint32(const void *a_, const void *b_)

{

  uint32_t a = *((uint32_t *)a_);

  uint32_t b = *((uint32_t *)b_);

  return (a < b) ? -1 : (a != b);

}

static int need_large_offset(off_t offset, const struct pack_idx_option *opts)

{

  uint32_t ofsval;

  if ((offset >> 31) || (opts->off32_limit < offset))

    return 1;

  if (!opts->anomaly_nr)

    return 0;

  ofsval = offset;

  return !!bsearch(&ofsval, opts->anomaly, opts->anomaly_nr,

       sizeof(ofsval), cmp_uint32);

}

/*

 * The *sha1 contains the pack content SHA1 hash.

 * The objects array passed in will be sorted by SHA1 on exit.

 */

const char *write_idx_file(struct repository *repo,

         const char *index_name, struct pack_idx_entry **objects,

         int nr_objects, const struct pack_idx_option *opts,

         const unsigned char *sha1)

{

  struct hashfile *f;

  struct pack_idx_entry **sorted_by_sha, **list, **last;

  off_t last_obj_offset = 0;

  int i, fd;

  uint32_t index_version;

  if (nr_objects) {

    sorted_by_sha = objects;

    list = sorted_by_sha;

    last = sorted_by_sha + nr_objects;

    for (i = 0; i < nr_objects; ++i) {

      if (objects[i]->offset > last_obj_offset)

        last_obj_offset = objects[i]->offset;

    }

    QSORT(sorted_by_sha, nr_objects, sha1_compare);

  }

  else

    sorted_by_sha = list = last = NULL;

  if (opts->flags & WRITE_IDX_VERIFY) {

    assert(index_name);

    f = hashfd_check(repo->hash_algo, index_name);

  } else {

    if (!index_name) {

      struct strbuf tmp_file = STRBUF_INIT;

      fd = odb_mkstemp(repo->objects, &tmp_file,

           "pack/tmp_idx_XXXXXX");

      index_name = strbuf_detach(&tmp_file, NULL);

    } else {

      unlink(index_name);

      fd = xopen(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);

    }

    f = hashfd(repo->hash_algo, fd, index_name);

  }

  /* if last object's offset is >= 2^31 we should use index V2 */

  index_version = need_large_offset(last_obj_offset, opts) ? 2 : opts->version;

  /* index versions 2 and above need a header */

  if (index_version >= 2) {

    struct pack_idx_header hdr;

    hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);

    hdr.idx_version = htonl(index_version);

    hashwrite(f, &hdr, sizeof(hdr));

  }

  /*

   * Write the first-level table (the list is sorted,

   * but we use a 256-entry lookup to be able to avoid

   * having to do eight extra binary search iterations).

   */

  for (i = 0; i < 256; i++) {

    struct pack_idx_entry **next = list;

    while (next < last) {

      struct pack_idx_entry *obj = *next;

      if (obj->oid.hash[0] != i)

        break;

      next++;

    }

    hashwrite_be32(f, next - sorted_by_sha);

    list = next;

  }

  /*

   * Write the actual SHA1 entries..

   */

  list = sorted_by_sha;

  for (i = 0; i < nr_objects; i++) {

    struct pack_idx_entry *obj = *list++;

    if (index_version < 2)

      hashwrite_be32(f, obj->offset);

    hashwrite(f, obj->oid.hash, repo->hash_algo->rawsz);

    if ((opts->flags & WRITE_IDX_STRICT) &&

        (i && oideq(&list[-2]->oid, &obj->oid)))

      die("The same object %s appears twice in the pack",

          oid_to_hex(&obj->oid));

  }

  if (index_version >= 2) {

    unsigned int nr_large_offset = 0;

    /* write the crc32 table */

    list = sorted_by_sha;

    for (i = 0; i < nr_objects; i++) {

      struct pack_idx_entry *obj = *list++;

      hashwrite_be32(f, obj->crc32);

    }

    /* write the 32-bit offset table */

    list = sorted_by_sha;

    for (i = 0; i < nr_objects; i++) {

      struct pack_idx_entry *obj = *list++;

      uint32_t offset;

      offset = (need_large_offset(obj->offset, opts)

          ? (0x80000000 | nr_large_offset++)

          : obj->offset);

      hashwrite_be32(f, offset);

    }

    /* write the large offset table */

    list = sorted_by_sha;

    while (nr_large_offset) {

      struct pack_idx_entry *obj = *list++;

      uint64_t offset = obj->offset;

      if (!need_large_offset(offset, opts))

        continue;

      hashwrite_be64(f, offset);

      nr_large_offset--;

    }

  }

  hashwrite(f, sha1, repo->hash_algo->rawsz);

  finalize_hashfile(f, NULL, FSYNC_COMPONENT_PACK_METADATA,

        CSUM_HASH_IN_STREAM | CSUM_CLOSE |

        ((opts->flags & WRITE_IDX_VERIFY) ? 0 : CSUM_FSYNC));

  return index_name;

}

static int pack_order_cmp(const void *va, const void *vb, void *ctx)

{

  struct pack_idx_entry **objects = ctx;

  off_t oa = objects[*(uint32_t*)va]->offset;

  off_t ob = objects[*(uint32_t*)vb]->offset;

  if (oa < ob)

    return -1;

  if (oa > ob)

    return 1;

  return 0;

}

static void write_rev_header(const struct git_hash_algo *hash_algo,

           struct hashfile *f)

{

  hashwrite_be32(f, RIDX_SIGNATURE);

  hashwrite_be32(f, RIDX_VERSION);

  hashwrite_be32(f, oid_version(hash_algo));

}

static void write_rev_index_positions(struct hashfile *f,

              uint32_t *pack_order,

              uint32_t nr_objects)

{

  uint32_t i;

  for (i = 0; i < nr_objects; i++)

    hashwrite_be32(f, pack_order[i]);

}

static void write_rev_trailer(const struct git_hash_algo *hash_algo,

            struct hashfile *f, const unsigned char *hash)

{

  hashwrite(f, hash, hash_algo->rawsz);

}

char *write_rev_file(struct repository *repo,

         const char *rev_name,

         struct pack_idx_entry **objects,

         uint32_t nr_objects,

         const unsigned char *hash,

         unsigned flags)

{

  uint32_t *pack_order;

  uint32_t i;

  char *ret;

  if (!(flags & WRITE_REV) && !(flags & WRITE_REV_VERIFY))

    return NULL;

  ALLOC_ARRAY(pack_order, nr_objects);

  for (i = 0; i < nr_objects; i++)

    pack_order[i] = i;

  QSORT_S(pack_order, nr_objects, pack_order_cmp, objects);

  ret = write_rev_file_order(repo, rev_name, pack_order, nr_objects,

           hash, flags);

  free(pack_order);

  return ret;

}

char *write_rev_file_order(struct repository *repo,

         const char *rev_name,

         uint32_t *pack_order,

         uint32_t nr_objects,

         const unsigned char *hash,

         unsigned flags)

{

  struct hashfile *f;

  char *path;

  int fd;

  if ((flags & WRITE_REV) && (flags & WRITE_REV_VERIFY))

    die(_("cannot both write and verify reverse index"));

  if (flags & WRITE_REV) {

    if (!rev_name) {

      struct strbuf tmp_file = STRBUF_INIT;

      fd = odb_mkstemp(repo->objects, &tmp_file,

           "pack/tmp_rev_XXXXXX");

      path = strbuf_detach(&tmp_file, NULL);

    } else {

      unlink(rev_name);

      fd = xopen(rev_name, O_CREAT|O_EXCL|O_WRONLY, 0600);

      path = xstrdup(rev_name);

    }

    f = hashfd(repo->hash_algo, fd, path);

  } else if (flags & WRITE_REV_VERIFY) {

    struct stat statbuf;

    if (stat(rev_name, &statbuf)) {

      if (errno == ENOENT) {

        /* .rev files are optional */

        return NULL;

      } else

        die_errno(_("could not stat: %s"), rev_name);

    }

    f = hashfd_check(repo->hash_algo, rev_name);

    path = xstrdup(rev_name);

  } else {

    return NULL;

  }

  write_rev_header(repo->hash_algo, f);

  write_rev_index_positions(f, pack_order, nr_objects);

  write_rev_trailer(repo->hash_algo, f, hash);

  if (adjust_shared_perm(repo, path) < 0)

    die(_("failed to make %s readable"), path);

  finalize_hashfile(f, NULL, FSYNC_COMPONENT_PACK_METADATA,

        CSUM_HASH_IN_STREAM | CSUM_CLOSE |

        ((flags & WRITE_IDX_VERIFY) ? 0 : CSUM_FSYNC));

  return path;

}

static void write_mtimes_header(const struct git_hash_algo *hash_algo,

        struct hashfile *f)

{

  hashwrite_be32(f, MTIMES_SIGNATURE);

  hashwrite_be32(f, MTIMES_VERSION);

  hashwrite_be32(f, oid_version(hash_algo));

}

/*

 * Writes the object mtimes of "objects" for use in a .mtimes file.

 * Note that objects must be in lexicographic (index) order, which is

 * the expected ordering of these values in the .mtimes file.

 */

static void write_mtimes_objects(struct hashfile *f,

         struct packing_data *to_pack,

         struct pack_idx_entry **objects,

         uint32_t nr_objects)

{

  uint32_t i;

  for (i = 0; i < nr_objects; i++) {

    struct object_entry *e = (struct object_entry*)objects[i];

    hashwrite_be32(f, oe_cruft_mtime(to_pack, e));

  }

}

static void write_mtimes_trailer(const struct git_hash_algo *hash_algo,

         struct hashfile *f, const unsigned char *hash)

{

  hashwrite(f, hash, hash_algo->rawsz);

}

static char *write_mtimes_file(struct repository *repo,

             struct packing_data *to_pack,

             struct pack_idx_entry **objects,

             uint32_t nr_objects,

             const unsigned char *hash)

{

  struct strbuf tmp_file = STRBUF_INIT;

  char *mtimes_name;

  struct hashfile *f;

  int fd;

  if (!to_pack)

    BUG("cannot call write_mtimes_file with NULL packing_data");

  fd = odb_mkstemp(repo->objects, &tmp_file, "pack/tmp_mtimes_XXXXXX");

  mtimes_name = strbuf_detach(&tmp_file, NULL);

  f = hashfd(repo->hash_algo, fd, mtimes_name);

  write_mtimes_header(repo->hash_algo, f);

  write_mtimes_objects(f, to_pack, objects, nr_objects);

  write_mtimes_trailer(repo->hash_algo, f, hash);

  if (adjust_shared_perm(repo, mtimes_name) < 0)

    die(_("failed to make %s readable"), mtimes_name);

  finalize_hashfile(f, NULL, FSYNC_COMPONENT_PACK_METADATA,

        CSUM_HASH_IN_STREAM | CSUM_CLOSE | CSUM_FSYNC);

  return mtimes_name;

}

off_t write_pack_header(struct hashfile *f, uint32_t nr_entries)

{

  struct pack_header hdr;

  hdr.hdr_signature = htonl(PACK_SIGNATURE);

  hdr.hdr_version = htonl(PACK_VERSION);

  hdr.hdr_entries = htonl(nr_entries);

  hashwrite(f, &hdr, sizeof(hdr));

  return sizeof(hdr);

}

/*

 * Update pack header with object_count and compute new SHA1 for pack data

 * associated to pack_fd, and write that SHA1 at the end.  That new SHA1

 * is also returned in new_pack_sha1.

 *

 * If partial_pack_sha1 is non null, then the SHA1 of the existing pack

 * (without the header update) is computed and validated against the

 * one provided in partial_pack_sha1.  The validation is performed at

 * partial_pack_offset bytes in the pack file.  The SHA1 of the remaining

 * data (i.e. from partial_pack_offset to the end) is then computed and

 * returned in partial_pack_sha1.

 *

 * Note that new_pack_sha1 is updated last, so both new_pack_sha1 and

 * partial_pack_sha1 can refer to the same buffer if the caller is not

 * interested in the resulting SHA1 of pack data above partial_pack_offset.

 */

void fixup_pack_header_footer(const struct git_hash_algo *hash_algo,

       int pack_fd,

       unsigned char *new_pack_hash,

       const char *pack_name,

       uint32_t object_count,

       unsigned char *partial_pack_hash,

       off_t partial_pack_offset)

{

  int aligned_sz, buf_sz = 8 * 1024;

  struct git_hash_ctx old_hash_ctx, new_hash_ctx;

  struct pack_header hdr;

  char *buf;

  ssize_t read_result;

  hash_algo->init_fn(&old_hash_ctx);

  hash_algo->init_fn(&new_hash_ctx);

  if (lseek(pack_fd, 0, SEEK_SET) != 0)

    die_errno("Failed seeking to start of '%s'", pack_name);

  read_result = read_in_full(pack_fd, &hdr, sizeof(hdr));

  if (read_result < 0)

    die_errno("Unable to reread header of '%s'", pack_name);

  else if (read_result != sizeof(hdr))

    die_errno("Unexpected short read for header of '%s'",

        pack_name);

  if (lseek(pack_fd, 0, SEEK_SET) != 0)

    die_errno("Failed seeking to start of '%s'", pack_name);

  git_hash_update(&old_hash_ctx, &hdr, sizeof(hdr));

  hdr.hdr_entries = htonl(object_count);

  git_hash_update(&new_hash_ctx, &hdr, sizeof(hdr));

  write_or_die(pack_fd, &hdr, sizeof(hdr));

  partial_pack_offset -= sizeof(hdr);

  buf = xmalloc(buf_sz);

  aligned_sz = buf_sz - sizeof(hdr);

  for (;;) {

    ssize_t m, n;

    m = (partial_pack_hash && partial_pack_offset < aligned_sz) ?

      partial_pack_offset : aligned_sz;

    n = xread(pack_fd, buf, m);

    if (!n)

      break;

    if (n < 0)

      die_errno("Failed to checksum '%s'", pack_name);

    git_hash_update(&new_hash_ctx, buf, n);

    aligned_sz -= n;

    if (!aligned_sz)

      aligned_sz = buf_sz;

    if (!partial_pack_hash)

      continue;

    git_hash_update(&old_hash_ctx, buf, n);

    partial_pack_offset -= n;

    if (partial_pack_offset == 0) {

      unsigned char hash[GIT_MAX_RAWSZ];

      git_hash_final(hash, &old_hash_ctx);

      if (!hasheq(hash, partial_pack_hash,

            hash_algo))

        die("Unexpected checksum for %s "

            "(disk corruption?)", pack_name);

      /*

       * Now let's compute the SHA1 of the remainder of the

       * pack, which also means making partial_pack_offset

       * big enough not to matter anymore.

       */

      hash_algo->init_fn(&old_hash_ctx);

      partial_pack_offset = ~partial_pack_offset;

      partial_pack_offset -= MSB(partial_pack_offset, 1);

    }

  }

  free(buf);

  if (partial_pack_hash)

    git_hash_final(partial_pack_hash, &old_hash_ctx);

  git_hash_final(new_pack_hash, &new_hash_ctx);

  write_or_die(pack_fd, new_pack_hash, hash_algo->rawsz);

  fsync_component_or_die(FSYNC_COMPONENT_PACK, pack_fd, pack_name);

}

char *index_pack_lockfile(struct repository *r, int ip_out, int *is_well_formed)

{

  char packname[GIT_MAX_HEXSZ + 6];

  const int len = r->hash_algo->hexsz + 6;

  /*

   * The first thing we expect from index-pack's output

   * is "pack\t%40s\n" or "keep\t%40s\n" (46 bytes) where

   * %40s is the newly created pack SHA1 name.  In the "keep"

   * case, we need it to remove the corresponding .keep file

   * later on.  If we don't get that then tough luck with it.

   */

  if (read_in_full(ip_out, packname, len) == len && packname[len-1] == '\n') {

    const char *name;

    if (is_well_formed)

      *is_well_formed = 1;

    packname[len-1] = 0;

    if (skip_prefix(packname, "keep\t", &name))

      return xstrfmt("%s/pack/pack-%s.keep",

               repo_get_object_directory(r), name);

    return NULL;

  }

  if (is_well_formed)

    *is_well_formed = 0;

  return NULL;

}

/*

 * The per-object header is a pretty dense thing, which is

 *  - first byte: low four bits are "size", then three bits of "type",

 *    and the high bit is "size continues".

 *  - each byte afterwards: low seven bits are size continuation,

 *    with the high bit being "size continues"

 */

int encode_in_pack_object_header(unsigned char *hdr, int hdr_len,

         enum object_type type, uintmax_t size)

{

  int n = 1;

  unsigned char c;

  if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)

    die("bad type %d", type);

  c = (type << 4) | (size & 15);

  size >>= 4;

  while (size) {

    if (n == hdr_len)

      die("object size is too enormous to format");

    *hdr++ = c | 0x80;

    c = size & 0x7f;

    size >>= 7;

    n++;

  }

  *hdr = c;

  return n;

}

struct hashfile *create_tmp_packfile(struct repository *repo,

             char **pack_tmp_name)

{

  struct strbuf tmpname = STRBUF_INIT;

  int fd;

  fd = odb_mkstemp(repo->objects, &tmpname, "pack/tmp_pack_XXXXXX");

  *pack_tmp_name = strbuf_detach(&tmpname, NULL);

  return hashfd(repo->hash_algo, fd, *pack_tmp_name);

}

static void rename_tmp_packfile(struct repository *repo,

        struct strbuf *name_prefix, const char *source,

        const char *ext)

{

  size_t name_prefix_len = name_prefix->len;

  strbuf_addstr(name_prefix, ext);

  if (finalize_object_file(repo, source, name_prefix->buf))

    die("unable to rename temporary file to '%s'",

        name_prefix->buf);

  strbuf_setlen(name_prefix, name_prefix_len);

}

void rename_tmp_packfile_idx(struct repository *repo,

           struct strbuf *name_buffer,

           char **idx_tmp_name)

{

  rename_tmp_packfile(repo, name_buffer, *idx_tmp_name, "idx");

}

void stage_tmp_packfiles(struct repository *repo,

       struct strbuf *name_buffer,

       const char *pack_tmp_name,

       struct pack_idx_entry **written_list,

       uint32_t nr_written,

       struct packing_data *to_pack,

       struct pack_idx_option *pack_idx_opts,

       unsigned char hash[],

       char **idx_tmp_name)

{

  char *rev_tmp_name = NULL;

  char *mtimes_tmp_name = NULL;

  if (adjust_shared_perm(repo, pack_tmp_name))

    die_errno("unable to make temporary pack file readable");

  *idx_tmp_name = (char *)write_idx_file(repo, NULL, written_list,

                 nr_written, pack_idx_opts, hash);

  if (adjust_shared_perm(repo, *idx_tmp_name))

    die_errno("unable to make temporary index file readable");

  rev_tmp_name = write_rev_file(repo, NULL, written_list, nr_written,

              hash, pack_idx_opts->flags);

  if (pack_idx_opts->flags & WRITE_MTIMES) {

    mtimes_tmp_name = write_mtimes_file(repo, to_pack,

                written_list, nr_written,

                hash);

  }

  rename_tmp_packfile(repo, name_buffer, pack_tmp_name, "pack");

  if (rev_tmp_name)

    rename_tmp_packfile(repo, name_buffer, rev_tmp_name, "rev");

  if (mtimes_tmp_name)

    rename_tmp_packfile(repo, name_buffer, mtimes_tmp_name, "mtimes");

  free(rev_tmp_name);

  free(mtimes_tmp_name);

}

void write_promisor_file(const char *promisor_name, struct ref **sought, int nr_sought)

{

  int i, err;

  FILE *output = xfopen(promisor_name, "w");

  for (i = 0; i < nr_sought; i++)

    fprintf(output, "%s %s\n", oid_to_hex(&sought[i]->old_oid),

      sought[i]->name);

  err = ferror(output);

  err |= fclose(output);

  if (err)

    die(_("could not write '%s' promisor file"), promisor_name);

}