/*

 * Builtin "git clone"

 *

 * Copyright (c) 2007 Kristian Høgsberg <krh@redhat.com>,

 *     2008 Daniel Barkalow <barkalow@iabervon.org>

 * Based on git-commit.sh by Junio C Hamano and Linus Torvalds

 *

 * Clone a repository into a different directory that does not yet exist.

 */

#include "builtin.h"

#include "abspath.h"

#include "advice.h"

#include "config.h"

#include "copy.h"

#include "environment.h"

#include "gettext.h"

#include "hex.h"

#include "lockfile.h"

#include "parse-options.h"

#include "refs.h"

#include "refspec.h"

#include "object-file.h"

#include "object-store-ll.h"

#include "tree.h"

#include "tree-walk.h"

#include "unpack-trees.h"

#include "transport.h"

#include "strbuf.h"

#include "dir.h"

#include "dir-iterator.h"

#include "iterator.h"

#include "sigchain.h"

#include "branch.h"

#include "remote.h"

#include "run-command.h"

#include "setup.h"

#include "connected.h"

#include "packfile.h"

#include "path.h"

#include "pkt-line.h"

#include "list-objects-filter-options.h"

#include "hook.h"

#include "bundle.h"

#include "bundle-uri.h"

/*

 * Overall FIXMEs:

 *  - respect DB_ENVIRONMENT for .git/objects.

 *

 * Implementation notes:

 *  - dropping use-separate-remote and no-separate-remote compatibility

 *

 */

static const char * const builtin_clone_usage[] = {

  N_("git clone [<options>] [--] <repo> [<dir>]"),

  NULL

};

static int option_no_checkout, option_bare, option_mirror, option_single_branch = -1;

static int option_local = -1, option_no_hardlinks, option_shared;

static int option_no_tags;

static int option_shallow_submodules;

static int option_reject_shallow = -1;    /* unspecified */

static int config_reject_shallow = -1;    /* unspecified */

static int deepen;

static char *option_template, *option_depth, *option_since;

static char *option_origin = NULL;

static char *remote_name = NULL;

static char *option_branch = NULL;

static struct string_list option_not = STRING_LIST_INIT_NODUP;

static const char *real_git_dir;

static const char *ref_format;

static const char *option_upload_pack = "git-upload-pack";

static int option_verbosity;

static int option_progress = -1;

static int option_sparse_checkout;

static enum transport_family family;

static struct string_list option_config = STRING_LIST_INIT_NODUP;

static struct string_list option_required_reference = STRING_LIST_INIT_NODUP;

static struct string_list option_optional_reference = STRING_LIST_INIT_NODUP;

static int option_dissociate;

static int max_jobs = -1;

static struct string_list option_recurse_submodules = STRING_LIST_INIT_NODUP;

static struct list_objects_filter_options filter_options = LIST_OBJECTS_FILTER_INIT;

static int option_filter_submodules = -1;    /* unspecified */

static int config_filter_submodules = -1;    /* unspecified */

static struct string_list server_options = STRING_LIST_INIT_NODUP;

static int option_remote_submodules;

static const char *bundle_uri;

static int recurse_submodules_cb(const struct option *opt,

         const char *arg, int unset)

{

  if (unset)

    string_list_clear((struct string_list *)opt->value, 0);

  else if (arg)

    string_list_append((struct string_list *)opt->value, arg);

  else

    string_list_append((struct string_list *)opt->value,

           (const char *)opt->defval);

  return 0;

}

static struct option builtin_clone_options[] = {

  OPT__VERBOSITY(&option_verbosity),

  OPT_BOOL(0, "progress", &option_progress,

     N_("force progress reporting")),

  OPT_BOOL(0, "reject-shallow", &option_reject_shallow,

     N_("don't clone shallow repository")),

  OPT_BOOL('n', "no-checkout", &option_no_checkout,

     N_("don't create a checkout")),

  OPT_BOOL(0, "bare", &option_bare, N_("create a bare repository")),

  OPT_HIDDEN_BOOL(0, "naked", &option_bare,

      N_("create a bare repository")),

  OPT_BOOL(0, "mirror", &option_mirror,

     N_("create a mirror repository (implies --bare)")),

  OPT_BOOL('l', "local", &option_local,

    N_("to clone from a local repository")),

  OPT_BOOL(0, "no-hardlinks", &option_no_hardlinks,

        N_("don't use local hardlinks, always copy")),

  OPT_BOOL('s', "shared", &option_shared,

        N_("setup as shared repository")),

  { OPTION_CALLBACK, 0, "recurse-submodules", &option_recurse_submodules,

    N_("pathspec"), N_("initialize submodules in the clone"),

    PARSE_OPT_OPTARG, recurse_submodules_cb, (intptr_t)"." },

  OPT_ALIAS(0, "recursive", "recurse-submodules"),

  OPT_INTEGER('j', "jobs", &max_jobs,

        N_("number of submodules cloned in parallel")),

  OPT_STRING(0, "template", &option_template, N_("template-directory"),

       N_("directory from which templates will be used")),

  OPT_STRING_LIST(0, "reference", &option_required_reference, N_("repo"),

      N_("reference repository")),

  OPT_STRING_LIST(0, "reference-if-able", &option_optional_reference,

      N_("repo"), N_("reference repository")),

  OPT_BOOL(0, "dissociate", &option_dissociate,

     N_("use --reference only while cloning")),

  OPT_STRING('o', "origin", &option_origin, N_("name"),

       N_("use <name> instead of 'origin' to track upstream")),

  OPT_STRING('b', "branch", &option_branch, N_("branch"),

       N_("checkout <branch> instead of the remote's HEAD")),

  OPT_STRING('u', "upload-pack", &option_upload_pack, N_("path"),

       N_("path to git-upload-pack on the remote")),

  OPT_STRING(0, "depth", &option_depth, N_("depth"),

        N_("create a shallow clone of that depth")),

  OPT_STRING(0, "shallow-since", &option_since, N_("time"),

        N_("create a shallow clone since a specific time")),

  OPT_STRING_LIST(0, "shallow-exclude", &option_not, N_("revision"),

      N_("deepen history of shallow clone, excluding rev")),

  OPT_BOOL(0, "single-branch", &option_single_branch,

        N_("clone only one branch, HEAD or --branch")),

  OPT_BOOL(0, "no-tags", &option_no_tags,

     N_("don't clone any tags, and make later fetches not to follow them")),

  OPT_BOOL(0, "shallow-submodules", &option_shallow_submodules,

        N_("any cloned submodules will be shallow")),

  OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),

       N_("separate git dir from working tree")),

  OPT_STRING(0, "ref-format", &ref_format, N_("format"),

       N_("specify the reference format to use")),

  OPT_STRING_LIST('c', "config", &option_config, N_("key=value"),

      N_("set config inside the new repository")),

  OPT_STRING_LIST(0, "server-option", &server_options,

      N_("server-specific"), N_("option to transmit")),

  OPT_IPVERSION(&family),

  OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),

  OPT_BOOL(0, "also-filter-submodules", &option_filter_submodules,

        N_("apply partial clone filters to submodules")),

  OPT_BOOL(0, "remote-submodules", &option_remote_submodules,

        N_("any cloned submodules will use their remote-tracking branch")),

  OPT_BOOL(0, "sparse", &option_sparse_checkout,

        N_("initialize sparse-checkout file to include only files at root")),

  OPT_STRING(0, "bundle-uri", &bundle_uri,

       N_("uri"), N_("a URI for downloading bundles before fetching from origin remote")),

  OPT_END()

};

static const char *get_repo_path_1(struct strbuf *path, int *is_bundle)

{

  static const char *suffix[] = { "/.git", "", ".git/.git", ".git" };

  static const char *bundle_suffix[] = { ".bundle", "" };

  size_t baselen = path->len;

  struct stat st;

  int i;

  for (i = 0; i < ARRAY_SIZE(suffix); i++) {

    strbuf_setlen(path, baselen);

    strbuf_addstr(path, suffix[i]);

    if (stat(path->buf, &st))

      continue;

    if (S_ISDIR(st.st_mode) && is_git_directory(path->buf)) {

      *is_bundle = 0;

      return path->buf;

    } else if (S_ISREG(st.st_mode) && st.st_size > 8) {

      /* Is it a "gitfile"? */

      char signature[8];

      const char *dst;

      int len, fd = open(path->buf, O_RDONLY);

      if (fd < 0)

        continue;

      len = read_in_full(fd, signature, 8);

      close(fd);

      if (len != 8 || strncmp(signature, "gitdir: ", 8))

        continue;

      dst = read_gitfile(path->buf);

      if (dst) {

        *is_bundle = 0;

        return dst;

      }

    }

  }

  for (i = 0; i < ARRAY_SIZE(bundle_suffix); i++) {

    strbuf_setlen(path, baselen);

    strbuf_addstr(path, bundle_suffix[i]);

    if (!stat(path->buf, &st) && S_ISREG(st.st_mode)) {

      *is_bundle = 1;

      return path->buf;

    }

  }

  return NULL;

}

static char *get_repo_path(const char *repo, int *is_bundle)

{

  struct strbuf path = STRBUF_INIT;

  const char *raw;

  char *canon;

  strbuf_addstr(&path, repo);

  raw = get_repo_path_1(&path, is_bundle);

  canon = raw ? absolute_pathdup(raw) : NULL;

  strbuf_release(&path);

  return canon;

}

static int add_one_reference(struct string_list_item *item, void *cb_data)

{

  struct strbuf err = STRBUF_INIT;

  int *required = cb_data;

  char *ref_git = compute_alternate_path(item->string, &err);

  if (!ref_git) {

    if (*required)

      die("%s", err.buf);

    else

      fprintf(stderr,

        _("info: Could not add alternate for '%s': %s\n"),

        item->string, err.buf);

  } else {

    struct strbuf sb = STRBUF_INIT;

    strbuf_addf(&sb, "%s/objects", ref_git);

    add_to_alternates_file(sb.buf);

    strbuf_release(&sb);

  }

  strbuf_release(&err);

  free(ref_git);

  return 0;

}

static void setup_reference(void)

{

  int required = 1;

  for_each_string_list(&option_required_reference,

           add_one_reference, &required);

  required = 0;

  for_each_string_list(&option_optional_reference,

           add_one_reference, &required);

}

static void copy_alternates(struct strbuf *src, const char *src_repo)

{

  /*

   * Read from the source objects/info/alternates file

   * and copy the entries to corresponding file in the

   * destination repository with add_to_alternates_file().

   * Both src and dst have "$path/objects/info/alternates".

   *

   * Instead of copying bit-for-bit from the original,

   * we need to append to existing one so that the already

   * created entry via "clone -s" is not lost, and also

   * to turn entries with paths relative to the original

   * absolute, so that they can be used in the new repository.

   */

  FILE *in = xfopen(src->buf, "r");

  struct strbuf line = STRBUF_INIT;

  while (strbuf_getline(&line, in) != EOF) {

    char *abs_path;

    if (!line.len || line.buf[0] == '#')

      continue;

    if (is_absolute_path(line.buf)) {

      add_to_alternates_file(line.buf);

      continue;

    }

    abs_path = mkpathdup("%s/objects/%s", src_repo, line.buf);

    if (!normalize_path_copy(abs_path, abs_path))

      add_to_alternates_file(abs_path);

    else

      warning("skipping invalid relative alternate: %s/%s",

        src_repo, line.buf);

    free(abs_path);

  }

  strbuf_release(&line);

  fclose(in);

}

static void mkdir_if_missing(const char *pathname, mode_t mode)

{

  struct stat st;

  if (!mkdir(pathname, mode))

    return;

  if (errno != EEXIST)

    die_errno(_("failed to create directory '%s'"), pathname);

  else if (stat(pathname, &st))

    die_errno(_("failed to stat '%s'"), pathname);

  else if (!S_ISDIR(st.st_mode))

    die(_("%s exists and is not a directory"), pathname);

}

static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,

           const char *src_repo)

{

  int src_len, dest_len;

  struct dir_iterator *iter;

  int iter_status;

  /*

   * Refuse copying directories by default which aren't owned by us. The

   * code that performs either the copying or hardlinking is not prepared

   * to handle various edge cases where an adversary may for example

   * racily swap out files for symlinks. This can cause us to

   * inadvertently use the wrong source file.

   *

   * Furthermore, even if we were prepared to handle such races safely,

   * creating hardlinks across user boundaries is an inherently unsafe

   * operation as the hardlinked files can be rewritten at will by the

   * potentially-untrusted user. We thus refuse to do so by default.

   */

  die_upon_dubious_ownership(NULL, NULL, src_repo);

  mkdir_if_missing(dest->buf, 0777);

  iter = dir_iterator_begin(src->buf, DIR_ITERATOR_PEDANTIC);

  if (!iter) {

    if (errno == ENOTDIR) {

      int saved_errno = errno;

      struct stat st;

      if (!lstat(src->buf, &st) && S_ISLNK(st.st_mode))

        die(_("'%s' is a symlink, refusing to clone with --local"),

            src->buf);

      errno = saved_errno;

    }

    die_errno(_("failed to start iterator over '%s'"), src->buf);

  }

  strbuf_addch(src, '/');

  src_len = src->len;

  strbuf_addch(dest, '/');

  dest_len = dest->len;

  while ((iter_status = dir_iterator_advance(iter)) == ITER_OK) {

    strbuf_setlen(src, src_len);

    strbuf_addstr(src, iter->relative_path);

    strbuf_setlen(dest, dest_len);

    strbuf_addstr(dest, iter->relative_path);

    if (S_ISLNK(iter->st.st_mode))

      die(_("symlink '%s' exists, refusing to clone with --local"),

          iter->relative_path);

    if (S_ISDIR(iter->st.st_mode)) {

      mkdir_if_missing(dest->buf, 0777);

      continue;

    }

    /* Files that cannot be copied bit-for-bit... */

    if (!fspathcmp(iter->relative_path, "info/alternates")) {

      copy_alternates(src, src_repo);

      continue;

    }

    if (unlink(dest->buf) && errno != ENOENT)

      die_errno(_("failed to unlink '%s'"), dest->buf);

    if (!option_no_hardlinks) {

      if (!link(src->buf, dest->buf)) {

        struct stat st;

        /*

         * Sanity-check whether the created hardlink

         * actually links to the expected file now. This

         * catches time-of-check-time-of-use bugs in

         * case the source file was meanwhile swapped.

         */

        if (lstat(dest->buf, &st))

          die(_("hardlink cannot be checked at '%s'"), dest->buf);

        if (st.st_mode != iter->st.st_mode ||

            st.st_ino != iter->st.st_ino ||

            st.st_dev != iter->st.st_dev ||

            st.st_size != iter->st.st_size ||

            st.st_uid != iter->st.st_uid ||

            st.st_gid != iter->st.st_gid)

          die(_("hardlink different from source at '%s'"), dest->buf);

        continue;

      }

      if (option_local > 0)

        die_errno(_("failed to create link '%s'"), dest->buf);

      option_no_hardlinks = 1;

    }

    if (copy_file_with_time(dest->buf, src->buf, 0666))

      die_errno(_("failed to copy file to '%s'"), dest->buf);

  }

  if (iter_status != ITER_DONE) {

    strbuf_setlen(src, src_len);

    die(_("failed to iterate over '%s'"), src->buf);

  }

}

static void clone_local(const char *src_repo, const char *dest_repo)

{

  if (option_shared) {

    struct strbuf alt = STRBUF_INIT;

    get_common_dir(&alt, src_repo);

    strbuf_addstr(&alt, "/objects");

    add_to_alternates_file(alt.buf);

    strbuf_release(&alt);

  } else {

    struct strbuf src = STRBUF_INIT;

    struct strbuf dest = STRBUF_INIT;

    get_common_dir(&src, src_repo);

    get_common_dir(&dest, dest_repo);

    strbuf_addstr(&src, "/objects");

    strbuf_addstr(&dest, "/objects");

    copy_or_link_directory(&src, &dest, src_repo);

    strbuf_release(&src);

    strbuf_release(&dest);

  }

  if (0 <= option_verbosity)

    fprintf(stderr, _("done.\n"));

}

static const char *junk_work_tree;

static int junk_work_tree_flags;

static const char *junk_git_dir;

static int junk_git_dir_flags;

static enum {

  JUNK_LEAVE_NONE,

  JUNK_LEAVE_REPO,

  JUNK_LEAVE_ALL

} junk_mode = JUNK_LEAVE_NONE;

static const char junk_leave_repo_msg[] =

N_("Clone succeeded, but checkout failed.\n"

   "You can inspect what was checked out with 'git status'\n"

   "and retry with 'git restore --source=HEAD :/'\n");

static void remove_junk(void)

{

  struct strbuf sb = STRBUF_INIT;

  switch (junk_mode) {

  case JUNK_LEAVE_REPO:

    warning("%s", _(junk_leave_repo_msg));

    /* fall-through */

  case JUNK_LEAVE_ALL:

    return;

  default:

    /* proceed to removal */

    break;

  }

  if (junk_git_dir) {

    strbuf_addstr(&sb, junk_git_dir);

    remove_dir_recursively(&sb, junk_git_dir_flags);

    strbuf_reset(&sb);

  }

  if (junk_work_tree) {

    strbuf_addstr(&sb, junk_work_tree);

    remove_dir_recursively(&sb, junk_work_tree_flags);

  }

  strbuf_release(&sb);

}

static void remove_junk_on_signal(int signo)

{

  remove_junk();

  sigchain_pop(signo);

  raise(signo);

}

static struct ref *find_remote_branch(const struct ref *refs, const char *branch)

{

  struct ref *ref;

  struct strbuf head = STRBUF_INIT;

  strbuf_addstr(&head, "refs/heads/");

  strbuf_addstr(&head, branch);

  ref = find_ref_by_name(refs, head.buf);

  strbuf_release(&head);

  if (ref)

    return ref;

  strbuf_addstr(&head, "refs/tags/");

  strbuf_addstr(&head, branch);

  ref = find_ref_by_name(refs, head.buf);

  strbuf_release(&head);

  return ref;

}

static struct ref *wanted_peer_refs(const struct ref *refs,

    struct refspec *refspec)

{

  struct ref *head = copy_ref(find_ref_by_name(refs, "HEAD"));

  struct ref *local_refs = head;

  struct ref **tail = head ? &head->next : &local_refs;

  struct refspec_item tag_refspec;

  refspec_item_init(&tag_refspec, TAG_REFSPEC, 0);

  if (option_single_branch) {

    struct ref *remote_head = NULL;

    if (!option_branch)

      remote_head = guess_remote_head(head, refs, 0);

    else {

      free_one_ref(head);

      local_refs = head = NULL;

      tail = &local_refs;

      remote_head = copy_ref(find_remote_branch(refs, option_branch));

    }

    if (!remote_head && option_branch)

      warning(_("Could not find remote branch %s to clone."),

        option_branch);

    else {

      int i;

      for (i = 0; i < refspec->nr; i++)

        get_fetch_map(remote_head, &refspec->items[i],

                &tail, 0);

      /* if --branch=tag, pull the requested tag explicitly */

      get_fetch_map(remote_head, &tag_refspec, &tail, 0);

    }

    free_refs(remote_head);

  } else {

    int i;

    for (i = 0; i < refspec->nr; i++)

      get_fetch_map(refs, &refspec->items[i], &tail, 0);

  }

  if (!option_mirror && !option_single_branch && !option_no_tags)

    get_fetch_map(refs, &tag_refspec, &tail, 0);

  refspec_item_clear(&tag_refspec);

  return local_refs;

}

static void write_remote_refs(const struct ref *local_refs)

{

  const struct ref *r;

  struct ref_transaction *t;

  struct strbuf err = STRBUF_INIT;

  t = ref_store_transaction_begin(get_main_ref_store(the_repository),

          &err);

  if (!t)

    die("%s", err.buf);

  for (r = local_refs; r; r = r->next) {

    if (!r->peer_ref)

      continue;

    if (ref_transaction_create(t, r->peer_ref->name, &r->old_oid,

             NULL, 0, NULL, &err))

      die("%s", err.buf);

  }

  if (initial_ref_transaction_commit(t, &err))

    die("%s", err.buf);

  strbuf_release(&err);

  ref_transaction_free(t);

}

static void write_followtags(const struct ref *refs, const char *msg)

{

  const struct ref *ref;

  for (ref = refs; ref; ref = ref->next) {

    if (!starts_with(ref->name, "refs/tags/"))

      continue;

    if (ends_with(ref->name, "^{}"))

      continue;

    if (!repo_has_object_file_with_flags(the_repository, &ref->old_oid,

                 OBJECT_INFO_QUICK |

                 OBJECT_INFO_SKIP_FETCH_OBJECT))

      continue;

    refs_update_ref(get_main_ref_store(the_repository), msg,

        ref->name, &ref->old_oid, NULL, 0,

        UPDATE_REFS_DIE_ON_ERR);

  }

}

static const struct object_id *iterate_ref_map(void *cb_data)

{

  struct ref **rm = cb_data;

  struct ref *ref = *rm;

  /*

   * Skip anything missing a peer_ref, which we are not

   * actually going to write a ref for.

   */

  while (ref && !ref->peer_ref)

    ref = ref->next;

  if (!ref)

    return NULL;

  *rm = ref->next;

  return &ref->old_oid;

}

static void update_remote_refs(const struct ref *refs,

             const struct ref *mapped_refs,

             const struct ref *remote_head_points_at,

             const char *branch_top,

             const char *msg,

             struct transport *transport,

             int check_connectivity)

{

  const struct ref *rm = mapped_refs;

  if (check_connectivity) {

    struct check_connected_options opt = CHECK_CONNECTED_INIT;

    opt.transport = transport;

    opt.progress = transport->progress;

    if (check_connected(iterate_ref_map, &rm, &opt))

      die(_("remote did not send all necessary objects"));

  }

  if (refs) {

    write_remote_refs(mapped_refs);

    if (option_single_branch && !option_no_tags)

      write_followtags(refs, msg);

  }

  if (remote_head_points_at && !option_bare) {

    struct strbuf head_ref = STRBUF_INIT;

    strbuf_addstr(&head_ref, branch_top);

    strbuf_addstr(&head_ref, "HEAD");

    if (refs_update_symref(get_main_ref_store(the_repository), head_ref.buf,

               remote_head_points_at->peer_ref->name,

               msg) < 0)

      die(_("unable to update %s"), head_ref.buf);

    strbuf_release(&head_ref);

  }

}

static void update_head(const struct ref *our, const struct ref *remote,

      const char *unborn, const char *msg)

{

  const char *head;

  if (our && skip_prefix(our->name, "refs/heads/", &head)) {

    /* Local default branch link */

    if (refs_update_symref(get_main_ref_store(the_repository), "HEAD", our->name, NULL) < 0)

      die(_("unable to update HEAD"));

    if (!option_bare) {

      refs_update_ref(get_main_ref_store(the_repository),

          msg, "HEAD", &our->old_oid, NULL, 0,

          UPDATE_REFS_DIE_ON_ERR);

      install_branch_config(0, head, remote_name, our->name);

    }

  } else if (our) {

    struct commit *c = lookup_commit_reference(the_repository,

                 &our->old_oid);

    /* --branch specifies a non-branch (i.e. tags), detach HEAD */

    refs_update_ref(get_main_ref_store(the_repository), msg,

        "HEAD", &c->object.oid, NULL, REF_NO_DEREF,

        UPDATE_REFS_DIE_ON_ERR);

  } else if (remote) {

    /*

     * We know remote HEAD points to a non-branch, or

     * HEAD points to a branch but we don't know which one.

     * Detach HEAD in all these cases.

     */

    refs_update_ref(get_main_ref_store(the_repository), msg,

        "HEAD", &remote->old_oid, NULL, REF_NO_DEREF,

        UPDATE_REFS_DIE_ON_ERR);

  } else if (unborn && skip_prefix(unborn, "refs/heads/", &head)) {

    /*

     * Unborn head from remote; same as "our" case above except

     * that we have no ref to update.

     */

    if (refs_update_symref(get_main_ref_store(the_repository), "HEAD", unborn, NULL) < 0)

      die(_("unable to update HEAD"));

    if (!option_bare)

      install_branch_config(0, head, remote_name, unborn);

  }

}

static int git_sparse_checkout_init(const char *repo)

{

  struct child_process cmd = CHILD_PROCESS_INIT;

  int result = 0;

  strvec_pushl(&cmd.args, "-C", repo, "sparse-checkout", "set", NULL);

  /*

   * We must apply the setting in the current process

   * for the later checkout to use the sparse-checkout file.

   */

  core_apply_sparse_checkout = 1;

  cmd.git_cmd = 1;

  if (run_command(&cmd)) {

    error(_("failed to initialize sparse-checkout"));

    result = 1;

  }

  return result;

}

static int checkout(int submodule_progress, int filter_submodules,

        enum ref_storage_format ref_storage_format)

{

  struct object_id oid;

  char *head;

  struct lock_file lock_file = LOCK_INIT;

  struct unpack_trees_options opts;

  struct tree *tree;

  struct tree_desc t;

  int err = 0;

  if (option_no_checkout)

    return 0;

  head = refs_resolve_refdup(get_main_ref_store(the_repository), "HEAD",

           RESOLVE_REF_READING, &oid, NULL);

  if (!head) {

    warning(_("remote HEAD refers to nonexistent ref, "

        "unable to checkout"));

    return 0;

  }

  if (!strcmp(head, "HEAD")) {

    if (advice_enabled(ADVICE_DETACHED_HEAD))

      detach_advice(oid_to_hex(&oid));

    FREE_AND_NULL(head);

  } else {

    if (!starts_with(head, "refs/heads/"))

      die(_("HEAD not found below refs/heads!"));

  }

  /* We need to be in the new work tree for the checkout */

  setup_work_tree();

  repo_hold_locked_index(the_repository, &lock_file, LOCK_DIE_ON_ERROR);

  memset(&opts, 0, sizeof opts);

  opts.update = 1;

  opts.merge = 1;

  opts.clone = 1;

  opts.preserve_ignored = 0;

  opts.fn = oneway_merge;

  opts.verbose_update = (option_verbosity >= 0);

  opts.src_index = the_repository->index;

  opts.dst_index = the_repository->index;

  init_checkout_metadata(&opts.meta, head, &oid, NULL);

  tree = parse_tree_indirect(&oid);

  if (!tree)

    die(_("unable to parse commit %s"), oid_to_hex(&oid));

  if (parse_tree(tree) < 0)

    exit(128);

  init_tree_desc(&t, &tree->object.oid, tree->buffer, tree->size);

  if (unpack_trees(1, &t, &opts) < 0)

    die(_("unable to checkout working tree"));

  free(head);

  if (write_locked_index(the_repository->index, &lock_file, COMMIT_LOCK))

    die(_("unable to write new index file"));

  err |= run_hooks_l(the_repository, "post-checkout", oid_to_hex(null_oid()),

         oid_to_hex(&oid), "1", NULL);

  if (!err && (option_recurse_submodules.nr > 0)) {

    struct child_process cmd = CHILD_PROCESS_INIT;

    strvec_pushl(&cmd.args, "submodule", "update", "--require-init",

           "--recursive", NULL);

    if (option_shallow_submodules == 1)

      strvec_push(&cmd.args, "--depth=1");

    if (max_jobs != -1)

      strvec_pushf(&cmd.args, "--jobs=%d", max_jobs);

    if (submodule_progress)

      strvec_push(&cmd.args, "--progress");

    if (option_verbosity < 0)

      strvec_push(&cmd.args, "--quiet");

    if (option_remote_submodules) {

      strvec_push(&cmd.args, "--remote");

      strvec_push(&cmd.args, "--no-fetch");

    }

    if (ref_storage_format != REF_STORAGE_FORMAT_UNKNOWN)

      strvec_pushf(&cmd.args, "--ref-format=%s",

             ref_storage_format_to_name(ref_storage_format));

    if (filter_submodules && filter_options.choice)

      strvec_pushf(&cmd.args, "--filter=%s",

             expand_list_objects_filter_spec(&filter_options));

    if (option_single_branch >= 0)

      strvec_push(&cmd.args, option_single_branch ?

                 "--single-branch" :

                 "--no-single-branch");

    cmd.git_cmd = 1;

    err = run_command(&cmd);

  }

  return err;

}

static int git_clone_config(const char *k, const char *v,

          const struct config_context *ctx, void *cb)

{

  if (!strcmp(k, "clone.defaultremotename")) {

    if (!v)

      return config_error_nonbool(k);

    free(remote_name);

    remote_name = xstrdup(v);

  }

  if (!strcmp(k, "clone.rejectshallow"))

    config_reject_shallow = git_config_bool(k, v);

  if (!strcmp(k, "clone.filtersubmodules"))

    config_filter_submodules = git_config_bool(k, v);

  return git_default_config(k, v, ctx, cb);

}

static int write_one_config(const char *key, const char *value,

          const struct config_context *ctx,

          void *data)

{

  /*

   * give git_clone_config a chance to write config values back to the

   * environment, since git_config_set_multivar_gently only deals with

   * config-file writes

   */

  int apply_failed = git_clone_config(key, value, ctx, data);

  if (apply_failed)

    return apply_failed;

  return git_config_set_multivar_gently(key,

                value ? value : "true",

                CONFIG_REGEX_NONE, 0);

}

static void write_config(struct string_list *config)

{

  int i;

  for (i = 0; i < config->nr; i++) {

    if (git_config_parse_parameter(config->items[i].string,

                 write_one_config, NULL) < 0)

      die(_("unable to write parameters to config file"));

  }

}

static void write_refspec_config(const char *src_ref_prefix,

    const struct ref *our_head_points_at,

    const struct ref *remote_head_points_at,

    struct strbuf *branch_top)

{

  struct strbuf key = STRBUF_INIT;

  struct strbuf value = STRBUF_INIT;

  if (option_mirror || !option_bare) {

    if (option_single_branch && !option_mirror) {

      if (option_branch) {

        if (starts_with(our_head_points_at->name, "refs/tags/"))

          strbuf_addf(&value, "+%s:%s", our_head_points_at->name,

            our_head_points_at->name);

        else

          strbuf_addf(&value, "+%s:%s%s", our_head_points_at->name,

            branch_top->buf, option_branch);

      } else if (remote_head_points_at) {