#define USE_THE_REPOSITORY_VARIABLE

#include "git-compat-util.h"

#include "gettext.h"

#include "hash.h"

#include "hex.h"

#include "lockfile.h"

#include "merge.h"

#include "commit.h"

#include "repository.h"

#include "run-command.h"

#include "resolve-undo.h"

#include "tree.h"

#include "tree-walk.h"

#include "unpack-trees.h"

static const char *merge_argument(struct commit *commit)

{

  return oid_to_hex(commit ? &commit->object.oid : the_hash_algo->empty_tree);

}

int try_merge_command(struct repository *r,

          const char *strategy, size_t xopts_nr,

          const char **xopts, struct commit_list *common,

          const char *head_arg, struct commit_list *remotes)

{

  struct child_process cmd = CHILD_PROCESS_INIT;

  int i, ret;

  struct commit_list *j;

  strvec_pushf(&cmd.args, "merge-%s", strategy);

  for (i = 0; i < xopts_nr; i++)

    strvec_pushf(&cmd.args, "--%s", xopts[i]);

  for (j = common; j; j = j->next)

    strvec_push(&cmd.args, merge_argument(j->item));

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

  strvec_push(&cmd.args, head_arg);

  for (j = remotes; j; j = j->next)

    strvec_push(&cmd.args, merge_argument(j->item));

  cmd.git_cmd = 1;

  ret = run_command(&cmd);

  discard_index(r->index);

  if (repo_read_index(r) < 0)

    die(_("failed to read the cache"));

  resolve_undo_clear_index(r->index);

  return ret;

}

int checkout_fast_forward(struct repository *r,

        const struct object_id *head,

        const struct object_id *remote,

        int overwrite_ignore)

{

  struct tree *trees[MAX_UNPACK_TREES];

  struct unpack_trees_options opts;

  struct tree_desc t[MAX_UNPACK_TREES];

  int i, nr_trees = 0;

  struct lock_file lock_file = LOCK_INIT;

  refresh_index(r->index, REFRESH_QUIET, NULL, NULL, NULL);

  if (repo_hold_locked_index(r, &lock_file, LOCK_REPORT_ON_ERROR) < 0)

    return -1;

  memset(&trees, 0, sizeof(trees));

  memset(&t, 0, sizeof(t));

  trees[nr_trees] = parse_tree_indirect(head);

  if (!trees[nr_trees++]) {

    rollback_lock_file(&lock_file);

    return -1;

  }

  trees[nr_trees] = parse_tree_indirect(remote);

  if (!trees[nr_trees++]) {

    rollback_lock_file(&lock_file);

    return -1;

  }

  for (i = 0; i < nr_trees; i++) {

    if (parse_tree(trees[i]) < 0) {

      rollback_lock_file(&lock_file);

      return -1;

    }

    init_tree_desc(t+i, &trees[i]->object.oid,

             trees[i]->buffer, trees[i]->size);

  }

  memset(&opts, 0, sizeof(opts));

  opts.preserve_ignored = !overwrite_ignore;

  opts.head_idx = 1;

  opts.src_index = r->index;

  opts.dst_index = r->index;

  opts.update = 1;

  opts.verbose_update = 1;

  opts.merge = 1;

  opts.fn = twoway_merge;

  init_checkout_metadata(&opts.meta, NULL, remote, NULL);

  setup_unpack_trees_porcelain(&opts, "merge");

  if (unpack_trees(nr_trees, t, &opts)) {

    rollback_lock_file(&lock_file);

    clear_unpack_trees_porcelain(&opts);

    return -1;

  }

  clear_unpack_trees_porcelain(&opts);

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

    return error(_("unable to write new index file"));

  return 0;

}