/src/git/odb.c

Source
#include "git-compat-util.h"
#include "abspath.h"
#include "chdir-notify.h"
#include "commit-graph.h"
#include "config.h"
#include "dir.h"
#include "environment.h"
#include "gettext.h"
#include "hex.h"
#include "khash.h"
#include "lockfile.h"
#include "loose.h"
#include "midx.h"
#include "object-file-convert.h"
#include "object-file.h"
#include "odb.h"
#include "packfile.h"
#include "path.h"
#include "promisor-remote.h"
#include "quote.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"

KHASH_INIT(odb_path_map, const char * /* key: odb_path */,
  struct odb_source *, 1, fspathhash, fspatheq)

/*
 * This is meant to hold a *small* number of objects that you would
 * want odb_read_object() to be able to return, but yet you do not want
 * to write them into the object store (e.g. a browse-only
 * application).
 */
struct cached_object_entry {
  struct object_id oid;
  struct cached_object {
    enum object_type type;
    const void *buf;
    unsigned long size;
  } value;
};

static const struct cached_object *find_cached_object(struct object_database *object_store,
                  const struct object_id *oid)
{
  static const struct cached_object empty_tree = {
    .type = OBJ_TREE,
    .buf = "",
  };
  const struct cached_object_entry *co = object_store->cached_objects;

  for (size_t i = 0; i < object_store->cached_object_nr; i++, co++)
    if (oideq(&co->oid, oid))
      return &co->value;

  if (oid->algo && oideq(oid, hash_algos[oid->algo].empty_tree))
    return &empty_tree;

  return NULL;
}

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);
}

/*
 * Return non-zero iff the path is usable as an alternate object database.
 */
static bool odb_is_source_usable(struct object_database *o, const char *path)
{
  int r;
  struct strbuf normalized_objdir = STRBUF_INIT;
  bool usable = false;

  strbuf_realpath(&normalized_objdir, o->sources->path, 1);

  /* Detect cases where alternate disappeared */
  if (!is_directory(path)) {
    error(_("object directory %s does not exist; "
      "check .git/objects/info/alternates"),
          path);
    goto out;
  }

  /*
   * Prevent the common mistake of listing the same
   * thing twice, or object directory itself.
   */
  if (!o->source_by_path) {
    khiter_t p;

    o->source_by_path = kh_init_odb_path_map();
    assert(!o->sources->next);
    p = kh_put_odb_path_map(o->source_by_path, o->sources->path, &r);
    assert(r == 1); /* never used */
    kh_value(o->source_by_path, p) = o->sources;
  }

  if (fspatheq(path, normalized_objdir.buf))
    goto out;

  if (kh_get_odb_path_map(o->source_by_path, path) < kh_end(o->source_by_path))
    goto out;

  usable = true;

out:
  strbuf_release(&normalized_objdir);
  return usable;
}

static void parse_alternates(const char *string,
           int sep,
           const char *relative_base,
           struct strvec *out)
{
  struct strbuf pathbuf = STRBUF_INIT;
  struct strbuf buf = STRBUF_INIT;

  if (!string || !*string)
    return;

  while (*string) {
    const char *end;

    strbuf_reset(&buf);
    strbuf_reset(&pathbuf);

    if (*string == '#') {
      /* comment; consume up to next separator */
      end = strchrnul(string, sep);
    } else if (*string == '"' && !unquote_c_style(&buf, string, &end)) {
      /*
       * quoted path; unquote_c_style has copied the
       * data for us and set "end". Broken quoting (e.g.,
       * an entry that doesn't end with a quote) falls
       * back to the unquoted case below.
       */
    } else {
      /* normal, unquoted path */
      end = strchrnul(string, sep);
      strbuf_add(&buf, string, end - string);
    }

    if (*end)
      end++;
    string = end;

    if (!buf.len)
      continue;

    if (!is_absolute_path(buf.buf) && relative_base) {
      strbuf_realpath(&pathbuf, relative_base, 1);
      strbuf_addch(&pathbuf, '/');
    }
    strbuf_addbuf(&pathbuf, &buf);

    strbuf_reset(&buf);
    if (!strbuf_realpath(&buf, pathbuf.buf, 0)) {
      error(_("unable to normalize alternate object path: %s"),
            pathbuf.buf);
      continue;
    }

    /*
     * The trailing slash after the directory name is given by
     * this function at the end. Remove duplicates.
     */
    while (buf.len && buf.buf[buf.len - 1] == '/')
      strbuf_setlen(&buf, buf.len - 1);

    strvec_push(out, buf.buf);
  }

  strbuf_release(&pathbuf);
  strbuf_release(&buf);
}

static void odb_source_read_alternates(struct odb_source *source,
               struct strvec *out)
{
  struct strbuf buf = STRBUF_INIT;
  char *path;

  path = xstrfmt("%s/info/alternates", source->path);
  if (strbuf_read_file(&buf, path, 1024) < 0) {
    warn_on_fopen_errors(path);
    free(path);
    return;
  }
  parse_alternates(buf.buf, '\n', source->path, out);

  strbuf_release(&buf);
  free(path);
}


static struct odb_source *odb_source_new(struct object_database *odb,
           const char *path,
           bool local)
{
  struct odb_source *source;

  CALLOC_ARRAY(source, 1);
  source->odb = odb;
  source->local = local;
  source->path = xstrdup(path);
  source->loose = odb_source_loose_new(source);

  return source;
}

static struct odb_source *odb_add_alternate_recursively(struct object_database *odb,
              const char *source,
              int depth)
{
  struct odb_source *alternate = NULL;
  struct strvec sources = STRVEC_INIT;
  khiter_t pos;
  int ret;

  if (!odb_is_source_usable(odb, source))
    goto error;

  alternate = odb_source_new(odb, source, false);

  /* add the alternate entry */
  *odb->sources_tail = alternate;
  odb->sources_tail = &(alternate->next);

  pos = kh_put_odb_path_map(odb->source_by_path, alternate->path, &ret);
  if (!ret)
    BUG("source must not yet exist");
  kh_value(odb->source_by_path, pos) = alternate;

  /* recursively add alternates */
  odb_source_read_alternates(alternate, &sources);
  if (sources.nr && depth + 1 > 5) {
    error(_("%s: ignoring alternate object stores, nesting too deep"),
          source);
  } else {
    for (size_t i = 0; i < sources.nr; i++)
      odb_add_alternate_recursively(odb, sources.v[i], depth + 1);
  }

 error:
  strvec_clear(&sources);
  return alternate;
}

static int odb_source_write_alternate(struct odb_source *source,
              const char *alternate)
{
  struct lock_file lock = LOCK_INIT;
  char *path = xstrfmt("%s/%s", source->path, "info/alternates");
  FILE *in, *out;
  int found = 0;
  int ret;

  hold_lock_file_for_update(&lock, path, LOCK_DIE_ON_ERROR);
  out = fdopen_lock_file(&lock, "w");
  if (!out) {
    ret = error_errno(_("unable to fdopen alternates lockfile"));
    goto out;
  }

  in = fopen(path, "r");
  if (in) {
    struct strbuf line = STRBUF_INIT;

    while (strbuf_getline(&line, in) != EOF) {
      if (!strcmp(alternate, line.buf)) {
        found = 1;
        break;
      }
      fprintf_or_die(out, "%s\n", line.buf);
    }

    strbuf_release(&line);
    fclose(in);
  } else if (errno != ENOENT) {
    ret = error_errno(_("unable to read alternates file"));
    goto out;
  }

  if (found) {
    rollback_lock_file(&lock);
  } else {
    fprintf_or_die(out, "%s\n", alternate);
    if (commit_lock_file(&lock)) {
      ret = error_errno(_("unable to move new alternates file into place"));
      goto out;
    }
  }

  ret = 0;

out:
  free(path);
  return ret;
}

void odb_add_to_alternates_file(struct object_database *odb,
        const char *dir)
{
  int ret = odb_source_write_alternate(odb->sources, dir);
  if (ret < 0)
    die(NULL);
  if (odb->loaded_alternates)
    odb_add_alternate_recursively(odb, dir, 0);
}

struct odb_source *odb_add_to_alternates_memory(struct object_database *odb,
            const char *dir)
{
  /*
   * Make sure alternates are initialized, or else our entry may be
   * overwritten when they are.
   */
  odb_prepare_alternates(odb);
  return odb_add_alternate_recursively(odb, dir, 0);
}

struct odb_source *odb_set_temporary_primary_source(struct object_database *odb,
                const char *dir, int will_destroy)
{
  struct odb_source *source;

  /*
   * Make sure alternates are initialized, or else our entry may be
   * overwritten when they are.
   */
  odb_prepare_alternates(odb);

  /*
   * Make a new primary odb and link the old primary ODB in as an
   * alternate
   */
  source = odb_source_new(odb, dir, false);

  /*
   * Disable ref updates while a temporary odb is active, since
   * the objects in the database may roll back.
   */
  odb->repo->disable_ref_updates = true;
  source->will_destroy = will_destroy;
  source->next = odb->sources;
  odb->sources = source;
  return source->next;
}

static void odb_source_free(struct odb_source *source)
{
  free(source->path);
  odb_source_loose_free(source->loose);
  free(source);
}

void odb_restore_primary_source(struct object_database *odb,
        struct odb_source *restore_source,
        const char *old_path)
{
  struct odb_source *cur_source = odb->sources;

  if (strcmp(old_path, cur_source->path))
    BUG("expected %s as primary object store; found %s",
        old_path, cur_source->path);

  if (cur_source->next != restore_source)
    BUG("we expect the old primary object store to be the first alternate");

  odb->repo->disable_ref_updates = false;
  odb->sources = restore_source;
  odb_source_free(cur_source);
}

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;
}

struct odb_source *odb_find_source(struct object_database *odb, const char *obj_dir)
{
  struct odb_source *source;
  char *obj_dir_real = real_pathdup(obj_dir, 1);
  struct strbuf odb_path_real = STRBUF_INIT;

  odb_prepare_alternates(odb);
  for (source = odb->sources; source; source = source->next) {
    strbuf_realpath(&odb_path_real, source->path, 1);
    if (!strcmp(obj_dir_real, odb_path_real.buf))
      break;
  }

  free(obj_dir_real);
  strbuf_release(&odb_path_real);

  return source;
}

struct odb_source *odb_find_source_or_die(struct object_database *odb, const char *obj_dir)
{
  struct odb_source *source = odb_find_source(odb, obj_dir);
  if (!source)
    die(_("could not find object directory matching %s"), obj_dir);
  return source;
}

void odb_add_submodule_source_by_path(struct object_database *odb,
              const char *path)
{
  string_list_insert(&odb->submodule_source_paths, path);
}

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 {
  odb_for_each_alternate_ref_fn *fn;
  void *payload;
};

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

  if (!strbuf_realpath(&path, alternate->path, 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);

  read_alternate_refs(alternate->odb->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;
  data.fn = cb;
  data.payload = payload;
  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 *alternate;
  int r = 0;

  odb_prepare_alternates(odb);
  for (alternate = odb->sources->next; alternate; alternate = alternate->next) {
    r = cb(alternate, payload);
    if (r)
      break;
  }
  return r;
}

void odb_prepare_alternates(struct object_database *odb)
{
  struct strvec sources = STRVEC_INIT;

  if (odb->loaded_alternates)
    return;

  parse_alternates(odb->alternate_db, PATH_SEP, NULL, &sources);
  odb_source_read_alternates(odb->sources, &sources);
  for (size_t i = 0; i < sources.nr; i++)
    odb_add_alternate_recursively(odb, sources.v[i], 0);

  odb->loaded_alternates = 1;

  strvec_clear(&sources);
}

int odb_has_alternates(struct object_database *odb)
{
  odb_prepare_alternates(odb);
  return !!odb->sources->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);
}

int fetch_if_missing = 1;

static int register_all_submodule_sources(struct object_database *odb)
{
  int ret = odb->submodule_source_paths.nr;

  for (size_t i = 0; i < odb->submodule_source_paths.nr; i++)
    odb_add_to_alternates_memory(odb,
               odb->submodule_source_paths.items[i].string);
  if (ret) {
    string_list_clear(&odb->submodule_source_paths, 0);
    trace2_data_intmax("submodule", odb->repo,
           "register_all_submodule_sources/registered", ret);
    if (git_env_bool("GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB", 0))
      BUG("register_all_submodule_sources() called");
  }
  return ret;
}

static int do_oid_object_info_extended(struct object_database *odb,
               const struct object_id *oid,
               struct object_info *oi, unsigned flags)
{
  const struct cached_object *co;
  const struct object_id *real = oid;
  int already_retried = 0;

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

  if (is_null_oid(real))
    return -1;

  co = find_cached_object(odb, real);
  if (co) {
    if (oi) {
      if (oi->typep)
        *(oi->typep) = co->type;
      if (oi->sizep)
        *(oi->sizep) = co->size;
      if (oi->disk_sizep)
        *(oi->disk_sizep) = 0;
      if (oi->delta_base_oid)
        oidclr(oi->delta_base_oid, odb->repo->hash_algo);
      if (oi->contentp)
        *oi->contentp = xmemdupz(co->buf, co->size);
      oi->whence = OI_CACHED;
    }
    return 0;
  }

  odb_prepare_alternates(odb);

  while (1) {
    struct odb_source *source;

    if (!packfile_store_read_object_info(odb->packfiles, real, oi, flags))
      return 0;

    /* Most likely it's a loose object. */
    for (source = odb->sources; source; source = source->next)
      if (!odb_source_loose_read_object_info(source, real, oi, flags))
        return 0;

    /* Not a loose object; someone else may have just packed it. */
    if (!(flags & OBJECT_INFO_QUICK)) {
      odb_reprepare(odb->repo->objects);
      if (!packfile_store_read_object_info(odb->packfiles, real, oi, flags))
        return 0;
    }

    /*
     * This might be an attempt at accessing a submodule object as
     * if it were in main object store (having called
     * `odb_add_submodule_source_by_path()` on that submodule's
     * ODB). If any such ODBs exist, register them and try again.
     */
    if (register_all_submodule_sources(odb))
      /* We added some alternates; retry */
      continue;

    /* Check if it is a missing object */
    if (fetch_if_missing && repo_has_promisor_remote(odb->repo) &&
        !already_retried &&
        !(flags & OBJECT_INFO_SKIP_FETCH_OBJECT)) {
      promisor_remote_get_direct(odb->repo, real, 1);
      already_retried = 1;
      continue;
    }

    if (flags & OBJECT_INFO_DIE_IF_CORRUPT) {
      const struct packed_git *p;
      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 ((p = has_packed_and_bad(odb->repo, real)))
        die(_("packed object %s (stored in %s) is corrupt"),
            oid_to_hex(real), p->pack_name);
    }
    return -1;
  }
}

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;
  unsigned long 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;
    }
  }
  input_oi->whence = new_oi.whence;
  input_oi->u = new_oi.u;
  return ret;
}

int odb_read_object_info_extended(struct object_database *odb,
          const struct object_id *oid,
          struct object_info *oi,
          unsigned flags)
{
  int 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,
       unsigned long *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, unsigned long len, enum object_type type,
           struct object_id *oid)
{
  struct cached_object_entry *co;
  char *co_buf;

  hash_object_file(odb->repo->hash_algo, buf, len, type, oid);
  if (odb_has_object(odb, oid, 0) ||
      find_cached_object(odb, oid))
    return 0;

  ALLOC_GROW(odb->cached_objects,
       odb->cached_object_nr + 1, odb->cached_object_alloc);
  co = &odb->cached_objects[odb->cached_object_nr++];
  co->value.size = len;
  co->value.type = type;
  co_buf = xmalloc(len);
  memcpy(co_buf, buf, len);
  co->value.buf = co_buf;
  oidcpy(&co->oid, oid);
  return 0;
}

void *odb_read_object(struct object_database *odb,
          const struct object_id *oid,
          enum object_type *type,
          unsigned long *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,
           unsigned long *size,
           struct object_id *actual_oid_return)
{
  enum object_type type;
  void *buffer;
  unsigned long 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,
         unsigned flags)
{
  unsigned object_info_flags = 0;

  if (!startup_info->have_repository)
    return 0;
  if (!(flags & HAS_OBJECT_RECHECK_PACKED))
    object_info_flags |= OBJECT_INFO_QUICK;
  if (!(flags & 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)
{
  struct odb_source *source;

  if (packfile_store_freshen_object(odb->packfiles, oid))
    return 1;

  odb_prepare_alternates(odb);
  for (source = odb->sources; source; source = source->next)
    if (odb_source_loose_freshen_object(source, oid))
      return 1;

  return 0;
}

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,
       struct object_id *compat_oid,
       unsigned flags)
{
  return odb_source_loose_write_object(odb->sources, buf, len, type,
               oid, compat_oid, flags);
}

int odb_write_object_stream(struct object_database *odb,
          struct odb_write_stream *stream, size_t len,
          struct object_id *oid)
{
  return odb_source_loose_write_stream(odb->sources, stream, len, oid);
}

static void odb_update_commondir(const char *name UNUSED,
         const char *old_cwd,
         const char *new_cwd,
         void *cb_data)
{
  struct object_database *odb = cb_data;
  struct tmp_objdir *tmp_objdir;
  struct odb_source *source;

  tmp_objdir = tmp_objdir_unapply_primary_odb();

  /*
   * In theory, we only have to do this for the primary object source, as
   * alternates' paths are always resolved to an absolute path.
   */
  for (source = odb->sources; source; source = source->next) {
    char *path;

    if (is_absolute_path(source->path))
      continue;

    path = reparent_relative_path(old_cwd, new_cwd,
                source->path);

    free(source->path);
    source->path = path;
  }

  if (tmp_objdir)
    tmp_objdir_reapply_primary_odb(tmp_objdir, old_cwd, new_cwd);
}

struct object_database *odb_new(struct repository *repo,
        const char *primary_source,
        const char *secondary_sources)
{
  struct object_database *o = xmalloc(sizeof(*o));
  char *to_free = NULL;

  memset(o, 0, sizeof(*o));
  o->repo = repo;
  o->packfiles = packfile_store_new(o);
  pthread_mutex_init(&o->replace_mutex, NULL);
  string_list_init_dup(&o->submodule_source_paths);

  if (!primary_source)
    primary_source = to_free = xstrfmt("%s/objects", repo->commondir);
  o->sources = odb_source_new(o, primary_source, true);
  o->sources_tail = &o->sources->next;
  o->alternate_db = xstrdup_or_null(secondary_sources);

  free(to_free);

  chdir_notify_register(NULL, odb_update_commondir, o);

  return o;
}

void odb_close(struct object_database *o)
{
  struct odb_source *source;

  packfile_store_close(o->packfiles);

  for (source = o->sources; source; source = source->next) {
    if (source->midx)
      close_midx(source->midx);
    source->midx = NULL;
  }

  close_commit_graph(o);
}

static void odb_free_sources(struct object_database *o)
{
  while (o->sources) {
    struct odb_source *next;

    next = o->sources->next;
    odb_source_free(o->sources);
    o->sources = next;
  }
  kh_destroy_odb_path_map(o->source_by_path);
  o->source_by_path = NULL;
}

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

  free(o->alternate_db);

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

  odb_free_sources(o);

  for (size_t i = 0; i < o->cached_object_nr; i++)
    free((char *) o->cached_objects[i].value.buf);
  free(o->cached_objects);

  odb_close(o);
  packfile_store_free(o->packfiles);
  string_list_clear(&o->submodule_source_paths, 0);

  chdir_notify_unregister(NULL, odb_update_commondir, o);

  free(o);
}

void odb_reprepare(struct object_database *o)
{
  struct odb_source *source;

  obj_read_lock();

  /*
   * Reprepare alt odbs, in case the alternates file was modified
   * during the course of this process. This only _adds_ odbs to
   * the linked list, so existing odbs will continue to exist for
   * the lifetime of the process.
   */
  o->loaded_alternates = 0;
  odb_prepare_alternates(o);

  for (source = o->sources; source; source = source->next)
    odb_source_loose_reprepare(source);

  o->approximate_object_count_valid = 0;

  packfile_store_reprepare(o->packfiles);

  obj_read_unlock();
}

struct odb_transaction *odb_transaction_begin(struct object_database *odb)
{
  return object_file_transaction_begin(odb->sources);
}

void odb_transaction_commit(struct odb_transaction *transaction)
{
  object_file_transaction_commit(transaction);
}

Coverage Report

Created: 2026-01-10 06:18