#include "git-compat-util.h"

#include "tmp-objdir.h"

#include "abspath.h"

#include "chdir-notify.h"

#include "dir.h"

#include "environment.h"

#include "object-file.h"

#include "path.h"

#include "string-list.h"

#include "strbuf.h"

#include "strvec.h"

#include "quote.h"

#include "odb.h"

#include "repository.h"

struct tmp_objdir {

  struct repository *repo;

  struct strbuf path;

  struct strvec env;

  struct odb_source *prev_source;

  int will_destroy;

};

/*

 * Allow only one tmp_objdir at a time in a running process, which simplifies

 * our atexit cleanup routines.  It's doubtful callers will ever need

 * more than one, and we can expand later if so.  You can have many such

 * tmp_objdirs simultaneously in many processes, of course.

 */

static struct tmp_objdir *the_tmp_objdir;

static void tmp_objdir_free(struct tmp_objdir *t)

{

  strbuf_release(&t->path);

  strvec_clear(&t->env);

  free(t);

}

int tmp_objdir_destroy(struct tmp_objdir *t)

{

  int err;

  if (!t)

    return 0;

  if (t == the_tmp_objdir)

    the_tmp_objdir = NULL;

  if (t->prev_source)

    odb_restore_primary_source(t->repo->objects, t->prev_source, t->path.buf);

  err = remove_dir_recursively(&t->path, 0);

  tmp_objdir_free(t);

  return err;

}

static void remove_tmp_objdir(void)

{

  tmp_objdir_destroy(the_tmp_objdir);

}

void tmp_objdir_discard_objects(struct tmp_objdir *t)

{

  remove_dir_recursively(&t->path, REMOVE_DIR_KEEP_TOPLEVEL);

}

/*

 * These env_* functions are for setting up the child environment; the

 * "replace" variant overrides the value of any existing variable with that

 * "key". The "append" variant puts our new value at the end of a list,

 * separated by PATH_SEP (which is what separate values in

 * GIT_ALTERNATE_OBJECT_DIRECTORIES).

 */

static void env_append(struct strvec *env, const char *key, const char *val)

{

  struct strbuf quoted = STRBUF_INIT;

  const char *old;

  /*

   * Avoid quoting if it's not necessary, for maximum compatibility

   * with older parsers which don't understand the quoting.

   */

  if (*val == '"' || strchr(val, PATH_SEP)) {

    strbuf_addch(&quoted, '"');

    quote_c_style(val, &quoted, NULL, 1);

    strbuf_addch(&quoted, '"');

    val = quoted.buf;

  }

  old = getenv(key);

  if (!old)

    strvec_pushf(env, "%s=%s", key, val);

  else

    strvec_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);

  strbuf_release(&quoted);

}

static void env_replace(struct strvec *env, const char *key, const char *val)

{

  strvec_pushf(env, "%s=%s", key, val);

}

static int setup_tmp_objdir(const char *root)

{

  char *path;

  int ret = 0;

  path = xstrfmt("%s/pack", root);

  ret = mkdir(path, 0777);

  free(path);

  return ret;

}

struct tmp_objdir *tmp_objdir_create(struct repository *r,

             const char *prefix)

{

  static int installed_handlers;

  struct tmp_objdir *t;

  if (the_tmp_objdir)

    BUG("only one tmp_objdir can be used at a time");

  t = xcalloc(1, sizeof(*t));

  t->repo = r;

  strbuf_init(&t->path, 0);

  strvec_init(&t->env);

  /*

   * Use a string starting with tmp_ so that the builtin/prune.c code

   * can recognize any stale objdirs left behind by a crash and delete

   * them.

   */

  strbuf_addf(&t->path, "%s/tmp_objdir-%s-XXXXXX",

        repo_get_object_directory(r), prefix);

  if (!mkdtemp(t->path.buf)) {

    /* free, not destroy, as we never touched the filesystem */

    tmp_objdir_free(t);

    return NULL;

  }

  the_tmp_objdir = t;

  if (!installed_handlers) {

    atexit(remove_tmp_objdir);

    installed_handlers++;

  }

  if (setup_tmp_objdir(t->path.buf)) {

    tmp_objdir_destroy(t);

    return NULL;

  }

  env_append(&t->env, ALTERNATE_DB_ENVIRONMENT,

       absolute_path(repo_get_object_directory(r)));

  env_replace(&t->env, DB_ENVIRONMENT, absolute_path(t->path.buf));

  env_replace(&t->env, GIT_QUARANTINE_ENVIRONMENT,

        absolute_path(t->path.buf));

  return t;

}

/*

 * Make sure we copy packfiles and their associated metafiles in the correct

 * order. All of these ends_with checks are slightly expensive to do in

 * the midst of a sorting routine, but in practice it shouldn't matter.

 * We will have a relatively small number of packfiles to order, and loose

 * objects exit early in the first line.

 */

static int pack_copy_priority(const char *name)

{

  if (!starts_with(name, "pack"))

    return 0;

  if (ends_with(name, ".keep"))

    return 1;

  if (ends_with(name, ".pack"))

    return 2;

  if (ends_with(name, ".rev"))

    return 3;

  if (ends_with(name, ".idx"))

    return 4;

  return 5;

}

static int pack_copy_cmp(const char *a, const char *b)

{

  return pack_copy_priority(a) - pack_copy_priority(b);

}

static int read_dir_paths(struct string_list *out, const char *path)

{

  DIR *dh;

  struct dirent *de;

  dh = opendir(path);

  if (!dh)

    return -1;

  while ((de = readdir(dh)))

    if (de->d_name[0] != '.')

      string_list_append(out, de->d_name);

  closedir(dh);

  return 0;

}

static int migrate_paths(struct tmp_objdir *t,

       struct strbuf *src, struct strbuf *dst,

       enum finalize_object_file_flags flags);

static int migrate_one(struct tmp_objdir *t,

           struct strbuf *src, struct strbuf *dst,

           enum finalize_object_file_flags flags)

{

  struct stat st;

  if (stat(src->buf, &st) < 0)

    return -1;

  if (S_ISDIR(st.st_mode)) {

    if (!mkdir(dst->buf, 0777)) {

      if (adjust_shared_perm(t->repo, dst->buf))

        return -1;

    } else if (errno != EEXIST)

      return -1;

    return migrate_paths(t, src, dst, flags);

  }

  return finalize_object_file_flags(t->repo, src->buf, dst->buf, flags);

}

static int is_loose_object_shard(const char *name)

{

  return strlen(name) == 2 && isxdigit(name[0]) && isxdigit(name[1]);

}

static int migrate_paths(struct tmp_objdir *t,

       struct strbuf *src, struct strbuf *dst,

       enum finalize_object_file_flags flags)

{

  size_t src_len = src->len, dst_len = dst->len;

  struct string_list paths = STRING_LIST_INIT_DUP;

  int ret = 0;

  if (read_dir_paths(&paths, src->buf) < 0)

    return -1;

  paths.cmp = pack_copy_cmp;

  string_list_sort(&paths);

  for (size_t i = 0; i < paths.nr; i++) {

    const char *name = paths.items[i].string;

    enum finalize_object_file_flags flags_copy = flags;

    strbuf_addf(src, "/%s", name);

    strbuf_addf(dst, "/%s", name);

    if (is_loose_object_shard(name))

      flags_copy |= FOF_SKIP_COLLISION_CHECK;

    ret |= migrate_one(t, src, dst, flags_copy);

    strbuf_setlen(src, src_len);

    strbuf_setlen(dst, dst_len);

  }

  string_list_clear(&paths, 0);

  return ret;

}

int tmp_objdir_migrate(struct tmp_objdir *t)

{

  struct strbuf src = STRBUF_INIT, dst = STRBUF_INIT;

  int ret;

  if (!t)

    return 0;

  if (t->prev_source) {

    if (t->repo->objects->sources->will_destroy)

      BUG("migrating an ODB that was marked for destruction");

    odb_restore_primary_source(t->repo->objects, t->prev_source, t->path.buf);

    t->prev_source = NULL;

  }

  strbuf_addbuf(&src, &t->path);

  strbuf_addstr(&dst, repo_get_object_directory(t->repo));

  ret = migrate_paths(t, &src, &dst, 0);

  strbuf_release(&src);

  strbuf_release(&dst);

  tmp_objdir_destroy(t);

  return ret;

}

const char **tmp_objdir_env(const struct tmp_objdir *t)

{

  if (!t)

    return NULL;

  return t->env.v;

}

void tmp_objdir_add_as_alternate(const struct tmp_objdir *t)

{

  odb_add_to_alternates_memory(t->repo->objects, t->path.buf);

}

void tmp_objdir_replace_primary_odb(struct tmp_objdir *t, int will_destroy)

{

  if (t->prev_source)

    BUG("the primary object database is already replaced");

  t->prev_source = odb_set_temporary_primary_source(t->repo->objects,

                t->path.buf, will_destroy);

  t->will_destroy = will_destroy;

}

struct tmp_objdir *tmp_objdir_unapply_primary_odb(void)

{

  if (!the_tmp_objdir || !the_tmp_objdir->prev_source)

    return NULL;

  odb_restore_primary_source(the_tmp_objdir->repo->objects,

           the_tmp_objdir->prev_source, the_tmp_objdir->path.buf);

  the_tmp_objdir->prev_source = NULL;

  return the_tmp_objdir;

}

void tmp_objdir_reapply_primary_odb(struct tmp_objdir *t, const char *old_cwd,

    const char *new_cwd)

{

  char *path;

  path = reparent_relative_path(old_cwd, new_cwd, t->path.buf);

  strbuf_reset(&t->path);

  strbuf_addstr(&t->path, path);

  free(path);

  tmp_objdir_replace_primary_odb(t, t->will_destroy);

}