/src/git/odb.c

Source
#include "git-compat-util.h"
#include "abspath.h"
#include "commit-graph.h"
#include "config.h"
#include "environment.h"
#include "gettext.h"
#include "hashmap.h"
#include "hex.h"
#include "lockfile.h"
#include "loose.h"
#include "midx.h"
#include "object-file-convert.h"
#include "object-file.h"
#include "object-name.h"
#include "odb.h"
#include "odb/source-files.h"
#include "odb/source-inmemory.h"
#include "path.h"
#include "promisor-remote.h"
#include "replace-object.h"
#include "run-command.h"
#include "setup.h"
#include "strbuf.h"
#include "strvec.h"
#include "submodule.h"
#include "tmp-objdir.h"
#include "trace2.h"
#include "write-or-die.h"

static const char * const object_storage_name_by_format[] = {
  [OBJECT_STORAGE_FORMAT_UNKNOWN] = "unknown",
  [OBJECT_STORAGE_FORMAT_FILES] = "files",
};

enum object_storage_format object_storage_format_by_name(const char *name)
{
  for (size_t i = 0; i < ARRAY_SIZE(object_storage_name_by_format); i++)
    if (!strcmp(object_storage_name_by_format[i], name))
      return i;
  return OBJECT_STORAGE_FORMAT_UNKNOWN;
}

const char *object_storage_format_to_name(enum object_storage_format format)
{
  if (format < 0 || format >= ARRAY_SIZE(object_storage_name_by_format))
    format = OBJECT_STORAGE_FORMAT_UNKNOWN;
  return object_storage_name_by_format[format];
}

enum object_storage_format object_storage_format_by_uri(const char *uri, char **payload)
{
  enum object_storage_format format;
  const char *schema_end;
  char *name;

  schema_end = strstr(uri, "://");
  if (!schema_end) {
    name = xstrdup(uri);
    if (payload)
      *payload = NULL;
  } else {
    name = xstrndup(uri, schema_end - uri);
    if (payload)
      *payload = *(schema_end + 3) ? xstrdup(schema_end + 3) : NULL;
  }

  format = object_storage_format_by_name(name);

  free(name);
  return format;
}

int odb_mkstemp(struct object_database *odb,
    struct strbuf *temp_filename, const char *pattern)
{
  int fd;
  /*
   * we let the umask do its job, don't try to be more
   * restrictive except to remove write permission.
   */
  int mode = 0444;
  repo_git_path_replace(odb->repo, temp_filename, "objects/%s", pattern);
  fd = git_mkstemp_mode(temp_filename->buf, mode);
  if (0 <= fd)
    return fd;

  /* slow path */
  /* some mkstemp implementations erase temp_filename on failure */
  repo_git_path_replace(odb->repo, temp_filename, "objects/%s", pattern);
  safe_create_leading_directories(odb->repo, temp_filename->buf);
  return xmkstemp_mode(temp_filename->buf, mode);
}

char *compute_alternate_path(const char *path, struct strbuf *err)
{
  char *ref_git = NULL;
  const char *repo;
  int seen_error = 0;

  ref_git = real_pathdup(path, 0);
  if (!ref_git) {
    seen_error = 1;
    strbuf_addf(err, _("path '%s' does not exist"), path);
    goto out;
  }

  repo = read_gitfile(ref_git);
  if (!repo)
    repo = read_gitfile(mkpath("%s/.git", ref_git));
  if (repo) {
    free(ref_git);
    ref_git = xstrdup(repo);
  }

  if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
    char *ref_git_git = mkpathdup("%s/.git", ref_git);
    free(ref_git);
    ref_git = ref_git_git;
  } else if (!is_directory(mkpath("%s/objects", ref_git))) {
    struct strbuf sb = STRBUF_INIT;
    seen_error = 1;
    if (get_common_dir(&sb, ref_git)) {
      strbuf_addf(err,
            _("reference repository '%s' as a linked "
              "checkout is not supported yet."),
            path);
      goto out;
    }

    strbuf_addf(err, _("reference repository '%s' is not a "
          "local repository."), path);
    goto out;
  }

  if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
    strbuf_addf(err, _("reference repository '%s' is shallow"),
          path);
    seen_error = 1;
    goto out;
  }

  if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
    strbuf_addf(err,
          _("reference repository '%s' is grafted"),
          path);
    seen_error = 1;
    goto out;
  }

out:
  if (seen_error) {
    FREE_AND_NULL(ref_git);
  }

  return ref_git;
}

static void fill_alternate_refs_command(struct repository *repo,
          struct child_process *cmd,
          const char *repo_path)
{
  const char *value;

  if (!repo_config_get_value(repo, "core.alternateRefsCommand", &value)) {
    cmd->use_shell = 1;

    strvec_push(&cmd->args, value);
    strvec_push(&cmd->args, repo_path);
  } else {
    cmd->git_cmd = 1;

    strvec_pushf(&cmd->args, "--git-dir=%s", repo_path);
    strvec_push(&cmd->args, "for-each-ref");
    strvec_push(&cmd->args, "--format=%(objectname)");

    if (!repo_config_get_value(repo, "core.alternateRefsPrefixes", &value)) {
      strvec_push(&cmd->args, "--");
      strvec_split(&cmd->args, value);
    }
  }

  strvec_pushv(&cmd->env, (const char **)local_repo_env);
  cmd->out = -1;
}

static void read_alternate_refs(struct repository *repo,
        const char *path,
        odb_for_each_alternate_ref_fn *cb,
        void *payload)
{
  struct child_process cmd = CHILD_PROCESS_INIT;
  struct strbuf line = STRBUF_INIT;
  FILE *fh;

  fill_alternate_refs_command(repo, &cmd, path);

  if (start_command(&cmd))
    return;

  fh = xfdopen(cmd.out, "r");
  while (strbuf_getline_lf(&line, fh) != EOF) {
    struct object_id oid;
    const char *p;

    if (parse_oid_hex_algop(line.buf, &oid, &p, repo->hash_algo) || *p) {
      warning(_("invalid line while parsing alternate refs: %s"),
        line.buf);
      break;
    }

    cb(&oid, payload);
  }

  fclose(fh);
  finish_command(&cmd);
  strbuf_release(&line);
}

struct alternate_refs_data {
  struct repository *repo;
  odb_for_each_alternate_ref_fn *fn;
  void *payload;
};

static int refs_from_alternate_cb(struct odb_files_dir *alternate,
          void *payload)
{
  struct strbuf path = STRBUF_INIT;
  size_t base_len;
  struct alternate_refs_data *cb = payload;

  if (!strbuf_realpath(&path, alternate->abspath, 0))
    goto out;
  if (!strbuf_strip_suffix(&path, "/objects"))
    goto out;
  base_len = path.len;

  /* Is this a git repository with refs? */
  strbuf_addstr(&path, "/refs");
  if (!is_directory(path.buf))
    goto out;
  strbuf_setlen(&path, base_len);

  /* A shallow or grafted repository may lack the history behind its refs. */
  strbuf_addstr(&path, "/shallow");
  if (!access(path.buf, F_OK))
    goto out;
  strbuf_setlen(&path, base_len);

  strbuf_addstr(&path, "/info/grafts");
  if (!access(path.buf, F_OK))
    goto out;
  strbuf_setlen(&path, base_len);

  read_alternate_refs(cb->repo, path.buf, cb->fn, cb->payload);

out:
  strbuf_release(&path);
  return 0;
}

void odb_for_each_alternate_ref(struct object_database *odb,
        odb_for_each_alternate_ref_fn cb, void *payload)
{
  struct alternate_refs_data data = {
    .fn = cb,
    .payload = payload,
    .repo = odb->repo,
  };
  odb_for_each_alternate(odb, refs_from_alternate_cb, &data);
}

int odb_for_each_alternate(struct object_database *odb,
       odb_for_each_alternate_fn cb, void *payload)
{
  struct odb_source_files *files = odb_source_files_downcast(odb->source);
  int r = 0;

  for (struct odb_files_dir *dir = files->dirs->next; dir; dir = dir->next) {
    r = cb(dir, payload);
    if (r)
      break;
  }
  return r;
}

int odb_has_alternates(struct object_database *odb)
{
  if (odb->source->type != ODB_SOURCE_FILES)
    return 0;
  return !!odb_source_files_downcast(odb->source)->dirs->next;
}

int obj_read_use_lock = 0;
pthread_mutex_t obj_read_mutex;

void enable_obj_read_lock(void)
{
  if (obj_read_use_lock)
    return;

  obj_read_use_lock = 1;
  init_recursive_mutex(&obj_read_mutex);
}

void disable_obj_read_lock(void)
{
  if (!obj_read_use_lock)
    return;

  obj_read_use_lock = 0;
  pthread_mutex_destroy(&obj_read_mutex);
}

static enum odb_read_status do_oid_object_info_extended(struct object_database *odb,
              const struct object_id *oid,
              struct object_info *oi, unsigned flags)
{
  struct strbuf corrupt_err = STRBUF_INIT;
  const struct object_id *real = oid;
  enum odb_read_status ret;

  if (flags & OBJECT_INFO_LOOKUP_REPLACE)
    real = lookup_replace_object(odb->repo, oid);

  if (is_null_oid(real))
    return -1;

  if (!odb_source_read_object_info(odb->inmemory_objects, oid, oi, flags, NULL))
    return 0;

  ret = odb_source_read_object_info(odb->source, real, oi, flags,
            &corrupt_err);
  if (ret == ODB_READ_NOT_FOUND &&
      odb->repo->fetch_if_missing &&
      !(flags & OBJECT_INFO_SKIP_FETCH_OBJECT) &&
      repo_has_promisor_remote(odb->repo)) {
    /* Try to fetch the missing object from a promisor remote. */
    promisor_remote_get_direct(odb->repo, real, 1);
    ret = odb_source_read_object_info(odb->source, real, oi, flags,
              &corrupt_err);
  }

  if (ret < 0 && (flags & OBJECT_INFO_DIE_IF_CORRUPT)) {
    if ((flags & OBJECT_INFO_LOOKUP_REPLACE) && !oideq(real, oid))
      die(_("replacement %s not found for %s"),
          oid_to_hex(real), oid_to_hex(oid));
    if (ret != ODB_READ_NOT_FOUND) {
      if (corrupt_err.len)
        die("%s", corrupt_err.buf);
      die(_("object %s is corrupt"), oid_to_hex(real));
    }
  }

  strbuf_release(&corrupt_err);
  return ret;
}

static int oid_object_info_convert(struct repository *r,
           const struct object_id *input_oid,
           struct object_info *input_oi, unsigned flags)
{
  const struct git_hash_algo *input_algo = &hash_algos[input_oid->algo];
  int do_die = flags & OBJECT_INFO_DIE_IF_CORRUPT;
  enum object_type type;
  struct object_id oid, delta_base_oid;
  struct object_info new_oi, *oi;
  size_t size;
  void *content;
  int ret;

  if (repo_oid_to_algop(r, input_oid, r->hash_algo, &oid)) {
    if (do_die)
      die(_("missing mapping of %s to %s"),
          oid_to_hex(input_oid), r->hash_algo->name);
    return -1;
  }

  /* Is new_oi needed? */
  oi = input_oi;
  if (input_oi && (input_oi->delta_base_oid || input_oi->sizep ||
       input_oi->contentp)) {
    new_oi = *input_oi;
    /* Does delta_base_oid need to be converted? */
    if (input_oi->delta_base_oid)
      new_oi.delta_base_oid = &delta_base_oid;
    /* Will the attributes differ when converted? */
    if (input_oi->sizep || input_oi->contentp) {
      new_oi.contentp = &content;
      new_oi.sizep = &size;
      new_oi.typep = &type;
    }
    oi = &new_oi;
  }

  ret = odb_read_object_info_extended(r->objects, &oid, oi, flags);
  if (ret)
    return -1;
  if (oi == input_oi)
    return ret;

  if (new_oi.contentp) {
    struct strbuf outbuf = STRBUF_INIT;

    if (type != OBJ_BLOB) {
      ret = convert_object_file(r, &outbuf,
              r->hash_algo, input_algo,
              content, size, type, !do_die);
      free(content);
      if (ret == -1)
        return -1;
      size = outbuf.len;
      content = strbuf_detach(&outbuf, NULL);
    }
    if (input_oi->sizep)
      *input_oi->sizep = size;
    if (input_oi->contentp)
      *input_oi->contentp = content;
    else
      free(content);
    if (input_oi->typep)
      *input_oi->typep = type;
  }
  if (new_oi.delta_base_oid == &delta_base_oid) {
    if (repo_oid_to_algop(r, &delta_base_oid, input_algo,
         input_oi->delta_base_oid)) {
      if (do_die)
        die(_("missing mapping of %s to %s"),
            oid_to_hex(&delta_base_oid),
            input_algo->name);
      return -1;
    }
  }
  if (input_oi->source_infop)
    *input_oi->source_infop = *new_oi.source_infop;
  return ret;
}

enum odb_read_status odb_read_object_info_extended(struct object_database *odb,
               const struct object_id *oid,
               struct object_info *oi,
               enum object_info_flags flags)
{
  enum odb_read_status ret;

  if (oid->algo && (hash_algo_by_ptr(odb->repo->hash_algo) != oid->algo))
    return oid_object_info_convert(odb->repo, oid, oi, flags);

  obj_read_lock();
  ret = do_oid_object_info_extended(odb, oid, oi, flags);
  obj_read_unlock();
  return ret;
}


/* returns enum object_type or negative */
int odb_read_object_info(struct object_database *odb,
       const struct object_id *oid,
       size_t *sizep)
{
  enum object_type type;
  struct object_info oi = OBJECT_INFO_INIT;

  oi.typep = &type;
  oi.sizep = sizep;
  if (odb_read_object_info_extended(odb, oid, &oi,
            OBJECT_INFO_LOOKUP_REPLACE) < 0)
    return -1;
  return type;
}

int odb_pretend_object(struct object_database *odb,
           void *buf, size_t len, enum object_type type,
           struct object_id *oid)
{
  hash_object_file(odb->repo->hash_algo, buf, len, type, oid);
  if (odb_has_object(odb, oid, 0))
    return 0;

  return odb_source_write_object(odb->inmemory_objects,
               buf, len, type, oid, NULL, NULL, 0);
}

void *odb_read_object(struct object_database *odb,
          const struct object_id *oid,
          enum object_type *type,
          size_t *size)
{
  struct object_info oi = OBJECT_INFO_INIT;
  unsigned flags = OBJECT_INFO_DIE_IF_CORRUPT | OBJECT_INFO_LOOKUP_REPLACE;
  void *data;

  oi.typep = type;
  oi.sizep = size;
  oi.contentp = &data;
  if (odb_read_object_info_extended(odb, oid, &oi, flags))
    return NULL;

  return data;
}

void *odb_read_object_peeled(struct object_database *odb,
           const struct object_id *oid,
           enum object_type required_type,
           size_t *size,
           struct object_id *actual_oid_return)
{
  enum object_type type;
  void *buffer;
  size_t isize;
  struct object_id actual_oid;

  oidcpy(&actual_oid, oid);
  while (1) {
    int ref_length = -1;
    const char *ref_type = NULL;

    buffer = odb_read_object(odb, &actual_oid, &type, &isize);
    if (!buffer)
      return NULL;
    if (type == required_type) {
      *size = isize;
      if (actual_oid_return)
        oidcpy(actual_oid_return, &actual_oid);
      return buffer;
    }
    /* Handle references */
    else if (type == OBJ_COMMIT)
      ref_type = "tree ";
    else if (type == OBJ_TAG)
      ref_type = "object ";
    else {
      free(buffer);
      return NULL;
    }
    ref_length = strlen(ref_type);

    if (ref_length + odb->repo->hash_algo->hexsz > isize ||
        memcmp(buffer, ref_type, ref_length) ||
        get_oid_hex_algop((char *) buffer + ref_length, &actual_oid,
              odb->repo->hash_algo)) {
      free(buffer);
      return NULL;
    }
    free(buffer);
    /* Now we have the ID of the referred-to object in
     * actual_oid.  Check again. */
  }
}

int odb_has_object(struct object_database *odb, const struct object_id *oid,
       enum odb_has_object_flags flags)
{
  unsigned object_info_flags = 0;

  if (!startup_info->have_repository)
    return 0;
  if (!(flags & ODB_HAS_OBJECT_RECHECK_PACKED))
    object_info_flags |= OBJECT_INFO_QUICK;
  if (!(flags & ODB_HAS_OBJECT_FETCH_PROMISOR))
    object_info_flags |= OBJECT_INFO_SKIP_FETCH_OBJECT;

  return odb_read_object_info_extended(odb, oid, NULL, object_info_flags) >= 0;
}

int odb_freshen_object(struct object_database *odb,
           const struct object_id *oid)
{
  return odb_source_freshen_object(odb->source, oid, NULL);
}

int odb_for_each_object_ext(struct object_database *odb,
          const struct object_info *request,
          odb_for_each_object_cb cb,
          void *cb_data,
          const struct odb_for_each_object_options *opts)
{
  return odb_source_for_each_object(odb->source, request, cb, cb_data, opts);
}

int odb_for_each_object(struct object_database *odb,
      const struct object_info *request,
      odb_for_each_object_cb cb,
      void *cb_data,
      enum odb_for_each_object_flags flags)
{
  struct odb_for_each_object_options opts = {
    .flags = flags,
  };
  return odb_for_each_object_ext(odb, request, cb, cb_data, &opts);
}

int odb_count_objects(struct object_database *odb,
          enum odb_count_objects_flags flags,
          unsigned long *out)
{
  unsigned long count = 0;
  int ret;

  if (odb->object_count_valid && odb->object_count_flags == flags) {
    *out = odb->object_count;
    return 0;
  }

  ret = odb_source_count_objects(odb->source, flags, &count);
  if (ret < 0)
    goto out;

  odb->object_count = count;
  odb->object_count_valid = 1;
  odb->object_count_flags = flags;

  *out = count;
  ret = 0;

out:
  return ret;
}

/*
 * Return the slot of the most-significant bit set in "val". There are various
 * ways to do this quickly with fls() or __builtin_clzl(), but speed is
 * probably not a big deal here.
 */
static unsigned msb(unsigned long val)
{
  unsigned r = 0;
  while (val >>= 1)
    r++;
  return r;
}

int odb_find_abbrev_len(struct object_database *odb,
      const struct object_id *oid,
      int min_length,
      unsigned *out)
{
  const struct git_hash_algo *algo =
    oid->algo ? &hash_algos[oid->algo] : odb->repo->hash_algo;
  const unsigned hexsz = algo->hexsz;
  unsigned len;
  int ret;

  if (min_length < 0) {
    unsigned long count;

    if (odb_count_objects(odb, ODB_COUNT_OBJECTS_APPROXIMATE, &count) < 0)
      count = 0;

    /*
     * Add one because the MSB only tells us the highest bit set,
     * not including the value of all the _other_ bits (so "15"
     * is only one off of 2^4, but the MSB is the 3rd bit.
     */
    len = msb(count) + 1;
    /*
     * We now know we have on the order of 2^len objects, which
     * expects a collision at 2^(len/2). But we also care about hex
     * chars, not bits, and there are 4 bits per hex. So all
     * together we need to divide by 2 and round up.
     */
    len = DIV_ROUND_UP(len, 2);
    /*
     * For very small repos, we stick with our regular fallback.
     */
    if (len < FALLBACK_DEFAULT_ABBREV)
      len = FALLBACK_DEFAULT_ABBREV;
  } else {
    len = min_length;
  }

  if (len >= hexsz || !len) {
    *out = hexsz;
    ret = 0;
    goto out;
  }

  ret = odb_source_find_abbrev_len(odb->source, oid, len, &len);
  *out = len;

out:
  return ret;
}

void odb_assert_oid_type(struct object_database *odb,
       const struct object_id *oid, enum object_type expect)
{
  enum object_type type = odb_read_object_info(odb, oid, NULL);
  if (type < 0)
    die(_("%s is not a valid object"), oid_to_hex(oid));
  if (type != expect)
    die(_("%s is not a valid '%s' object"), oid_to_hex(oid),
        type_name(expect));
}

int odb_write_object_ext(struct object_database *odb,
       const void *buf, unsigned long len,
       enum object_type type,
       struct object_id *oid,
       const struct object_id *compat_oid_in,
       enum odb_write_object_flags flags)
{
  const struct git_hash_algo *compat = odb->repo->compat_hash_algo;
  struct object_id compat_oid, *compat_oid_p = NULL;

  hash_object_file(odb->repo->hash_algo, buf, len, type, oid);

  /*
   * We can skip the write in case we already have the object available.
   * In that case, we only freshen its mtime.
   */
  if (odb_freshen_object(odb, oid))
    return 0;

  if (compat) {
    const struct git_hash_algo *algo = odb->repo->hash_algo;

    if (compat_oid_in) {
      oidcpy(&compat_oid, compat_oid_in);
    } else if (type == OBJ_BLOB) {
      hash_object_file(compat, buf, len, type, &compat_oid);
    } else {
      struct strbuf converted = STRBUF_INIT;
      convert_object_file(odb->repo, &converted, algo, compat,
              buf, len, type, 0);
      hash_object_file(compat, converted.buf, converted.len,
           type, &compat_oid);
      strbuf_release(&converted);
    }

    compat_oid_p = &compat_oid;
  }

  return odb_source_write_object(odb->source, buf, len, type,
               oid, compat_oid_p, NULL, flags);
}

int odb_write_object_stream(struct object_database *odb,
          struct odb_stream *stream,
          struct object_id *oid)
{
  return odb_source_write_object_stream(odb->source, stream, oid);
}

int odb_optimize(struct object_database *odb,
     const struct odb_optimize_options *opts)
{
  return odb_source_optimize(odb->source, opts);
}

bool odb_optimize_required(struct object_database *odb,
         const struct odb_optimize_options *opts)
{
  return odb_source_optimize_required(odb->source, opts);
}

void odb_generate_pack_options_release(struct odb_generate_pack_options *opts)
{
  oid_array_clear(&opts->wants);
  oid_array_clear(&opts->haves);
  oid_array_clear(&opts->shallows);
}

int odb_generate_pack(struct object_database *odb,
          struct odb_pack_generator **out,
          const struct odb_generate_pack_options *opts)
{
  if (!odb->source->generate_pack)
    return error(_("primary object source does not support generating packfiles"));
  return odb_source_generate_pack(odb->source, out, opts);
}

int odb_pack_generator_finish(struct odb_pack_generator *generator)
{
  return generator->finish(generator);
}

struct object_database *odb_new(struct repository *repo,
        enum odb_new_flags flags)
{
  struct object_database *o;

  CALLOC_ARRAY(o, 1);
  o->repo = repo;
  pthread_mutex_init(&o->replace_mutex, NULL);

  o->source = odb_source_new(o, repo->object_storage_format,
           repo->object_storage_payload, flags);
  o->inmemory_objects = &odb_source_inmemory_new(o)->base;

  return o;
}

void odb_close(struct object_database *o)
{
  odb_source_close(o->source);
  close_commit_graph(o);
}

static void odb_free_sources(struct object_database *o)
{
  odb_source_free(o->source);
  odb_source_free(o->inmemory_objects);
  o->inmemory_objects = NULL;
}

void odb_free(struct object_database *o)
{
  if (!o)
    return;

  oidmap_clear(&o->replace_map, 1);
  pthread_mutex_destroy(&o->replace_mutex);

  odb_close(o);
  odb_free_sources(o);

  free(o);
}

void odb_prepare(struct object_database *o, enum odb_prepare_flags flags)
{
  obj_read_lock();

  if (flags & ODB_PREPARE_FLUSH_CACHES)
    o->object_count_valid = 0;

  odb_source_prepare(o->source, flags);

  obj_read_unlock();
}

void odb_reprepare(struct object_database *o)
{
  odb_prepare(o, ODB_PREPARE_FLUSH_CACHES);
}

int odb_fsck(struct object_database *odb, struct odb_fsck_options *options)
{
  return odb_source_fsck(odb->source, options);
}

Coverage Report

Created: 2026-11-12 06:03