#define USE_THE_REPOSITORY_VARIABLE

#include "git-compat-util.h"

#include "gettext.h"

#include "strbuf.h"

#include "hex.h"

#include "repository.h"

#include "hash.h"

#include "hash.h"

#include "object.h"

#include "loose.h"

#include "commit.h"

#include "gpg-interface.h"

#include "object-file-convert.h"

int repo_oid_to_algop(struct repository *repo, const struct object_id *src,

          const struct git_hash_algo *to, struct object_id *dest)

{

  /*

   * If the source algorithm is not set, then we're using the

   * default hash algorithm for that object.

   */

  const struct git_hash_algo *from =

    src->algo ? &hash_algos[src->algo] : repo->hash_algo;

  if (from == to) {

    if (src != dest)

      oidcpy(dest, src);

    return 0;

  }

  if (repo_loose_object_map_oid(repo, src, to, dest)) {

    /*

     * We may have loaded the object map at repo initialization but

     * another process (perhaps upstream of a pipe from us) may have

     * written a new object into the map.  If the object is missing,

     * let's reload the map to see if the object has appeared.

     */

    repo_read_loose_object_map(repo);

    if (repo_loose_object_map_oid(repo, src, to, dest))

      return -1;

  }

  return 0;

}

static int decode_tree_entry_raw(struct object_id *oid, const char **path,

         size_t *len, const struct git_hash_algo *algo,

         const char *buf, unsigned long size)

{

  uint16_t mode;

  const unsigned hashsz = algo->rawsz;

  if (size < hashsz + 3 || buf[size - (hashsz + 1)]) {

    return -1;

  }

  *path = parse_mode(buf, &mode);

  if (!*path || !**path)

    return -1;

  *len = strlen(*path) + 1;

  oidread(oid, (const unsigned char *)*path + *len, algo);

  return 0;

}

static int convert_tree_object(struct strbuf *out,

             const struct git_hash_algo *from,

             const struct git_hash_algo *to,

             const char *buffer, size_t size)

{

  const char *p = buffer, *end = buffer + size;

  while (p < end) {

    struct object_id entry_oid, mapped_oid;

    const char *path = NULL;

    size_t pathlen;

    if (decode_tree_entry_raw(&entry_oid, &path, &pathlen, from, p,

            end - p))

      return error(_("failed to decode tree entry"));

    if (repo_oid_to_algop(the_repository, &entry_oid, to, &mapped_oid))

      return error(_("failed to map tree entry for %s"), oid_to_hex(&entry_oid));

    strbuf_add(out, p, path - p);

    strbuf_add(out, path, pathlen);

    strbuf_add(out, mapped_oid.hash, to->rawsz);

    p = path + pathlen + from->rawsz;

  }

  return 0;

}

static int convert_tag_object(struct strbuf *out,

            const struct git_hash_algo *from,

            const struct git_hash_algo *to,

            const char *buffer, size_t size)

{

  struct strbuf payload = STRBUF_INIT, oursig = STRBUF_INIT, othersig = STRBUF_INIT;

  const int entry_len = from->hexsz + 7;

  size_t payload_size;

  struct object_id oid, mapped_oid;

  const char *p;

  /* Consume the object line */

  if ((entry_len >= size) ||

      memcmp(buffer, "object ", 7) || buffer[entry_len] != '\n')

    return error("bogus tag object");

  if (parse_oid_hex_algop(buffer + 7, &oid, &p, from) < 0)

    return error("bad tag object ID");

  if (repo_oid_to_algop(the_repository, &oid, to, &mapped_oid))

    return error("unable to map tree %s in tag object",

           oid_to_hex(&oid));

  size -= ((p + 1) - buffer);

  buffer = p + 1;

  /* Is there a signature for our algorithm? */

  payload_size = parse_signed_buffer(buffer, size);

  if (payload_size != size) {

    /* Yes, there is. */

    strbuf_add(&oursig, buffer + payload_size, size - payload_size);

  }

  /* Now, is there a signature for the other algorithm? */

  parse_buffer_signed_by_header(buffer, payload_size, &payload, &othersig, to);

  /*

   * Our payload is now in payload and we may have up to two signatrures

   * in oursig and othersig.

   */

  /* Add some slop for longer signature header in the new algorithm. */

  strbuf_grow(out, (7 + to->hexsz + 1) + size + 7);

  strbuf_addf(out, "object %s\n", oid_to_hex(&mapped_oid));

  strbuf_addbuf(out, &payload);

  if (oursig.len)

    add_header_signature(out, &oursig, from);

  strbuf_addbuf(out, &othersig);

  strbuf_release(&payload);

  strbuf_release(&othersig);

  strbuf_release(&oursig);

  return 0;

}

static int convert_commit_object(struct strbuf *out,

         const struct git_hash_algo *from,

         const struct git_hash_algo *to,

         const char *buffer, size_t size)

{

  const char *tail = buffer;

  const char *bufptr = buffer;

  const int tree_entry_len = from->hexsz + 5;

  const int parent_entry_len = from->hexsz + 7;

  struct object_id oid, mapped_oid;

  const char *p, *eol;

  tail += size;

  while ((bufptr < tail) && (*bufptr != '\n')) {

    eol = memchr(bufptr, '\n', tail - bufptr);

    if (!eol)

      return error(_("bad %s in commit"), "line");

    if (((bufptr + 5) < eol) && !memcmp(bufptr, "tree ", 5))

    {

      if (((bufptr + tree_entry_len) != eol) ||

          parse_oid_hex_algop(bufptr + 5, &oid, &p, from) ||

          (p != eol))

        return error(_("bad %s in commit"), "tree");

      if (repo_oid_to_algop(the_repository, &oid, to, &mapped_oid))

        return error(_("unable to map %s %s in commit object"),

               "tree", oid_to_hex(&oid));

      strbuf_addf(out, "tree %s\n", oid_to_hex(&mapped_oid));

    }

    else if (((bufptr + 7) < eol) && !memcmp(bufptr, "parent ", 7))

    {

      if (((bufptr + parent_entry_len) != eol) ||

          parse_oid_hex_algop(bufptr + 7, &oid, &p, from) ||

          (p != eol))

        return error(_("bad %s in commit"), "parent");

      if (repo_oid_to_algop(the_repository, &oid, to, &mapped_oid))

        return error(_("unable to map %s %s in commit object"),

               "parent", oid_to_hex(&oid));

      strbuf_addf(out, "parent %s\n", oid_to_hex(&mapped_oid));

    }

    else if (((bufptr + 9) < eol) && !memcmp(bufptr, "mergetag ", 9))

    {

      struct strbuf tag = STRBUF_INIT, new_tag = STRBUF_INIT;

      /* Recover the tag object from the mergetag */

      strbuf_add(&tag, bufptr + 9, (eol - (bufptr + 9)) + 1);

      bufptr = eol + 1;

      while ((bufptr < tail) && (*bufptr == ' ')) {

        eol = memchr(bufptr, '\n', tail - bufptr);

        if (!eol) {

          strbuf_release(&tag);

          return error(_("bad %s in commit"), "mergetag continuation");

        }

        strbuf_add(&tag, bufptr + 1, (eol - (bufptr + 1)) + 1);

        bufptr = eol + 1;

      }

      /* Compute the new tag object */

      if (convert_tag_object(&new_tag, from, to, tag.buf, tag.len)) {

        strbuf_release(&tag);

        strbuf_release(&new_tag);

        return -1;

      }

      /* Write the new mergetag */

      strbuf_addstr(out, "mergetag");

      strbuf_add_lines(out, " ", new_tag.buf, new_tag.len);

      strbuf_release(&tag);

      strbuf_release(&new_tag);

    }

    else if (((bufptr + 7) < tail) && !memcmp(bufptr, "author ", 7))

      strbuf_add(out, bufptr, (eol - bufptr) + 1);

    else if (((bufptr + 10) < tail) && !memcmp(bufptr, "committer ", 10))

      strbuf_add(out, bufptr, (eol - bufptr) + 1);

    else if (((bufptr + 9) < tail) && !memcmp(bufptr, "encoding ", 9))

      strbuf_add(out, bufptr, (eol - bufptr) + 1);

    else if (((bufptr + 6) < tail) && !memcmp(bufptr, "gpgsig", 6))

      strbuf_add(out, bufptr, (eol - bufptr) + 1);

    else {

      /* Unknown line fail it might embed an oid */

      return -1;

    }

    /* Consume any trailing continuation lines */

    bufptr = eol + 1;

    while ((bufptr < tail) && (*bufptr == ' ')) {

      eol = memchr(bufptr, '\n', tail - bufptr);

      if (!eol)

        return error(_("bad %s in commit"), "continuation");

      strbuf_add(out, bufptr, (eol - bufptr) + 1);

      bufptr = eol + 1;

    }

  }

  if (bufptr < tail)

    strbuf_add(out, bufptr, tail - bufptr);

  return 0;

}

int convert_object_file(struct strbuf *outbuf,

      const struct git_hash_algo *from,

      const struct git_hash_algo *to,

      const void *buf, size_t len,

      enum object_type type,

      int gentle)

{

  int ret;

  /* Don't call this function when no conversion is necessary */

  if ((from == to) || (type == OBJ_BLOB))

    BUG("Refusing noop object file conversion");

  switch (type) {

  case OBJ_COMMIT:

    ret = convert_commit_object(outbuf, from, to, buf, len);

    break;

  case OBJ_TREE:

    ret = convert_tree_object(outbuf, from, to, buf, len);

    break;

  case OBJ_TAG:

    ret = convert_tag_object(outbuf, from, to, buf, len);

    break;

  default:

    /* Not implemented yet, so fail. */

    ret = -1;

    break;

  }

  if (!ret)

    return 0;

  if (gentle) {

    strbuf_release(outbuf);

    return ret;

  }

  die(_("Failed to convert object from %s to %s"),

    from->name, to->name);

}