/*

 * "git reset" builtin command

 *

 * Copyright (c) 2007 Carlos Rica

 *

 * Based on git-reset.sh, which is

 *

 * Copyright (c) 2005, 2006 Linus Torvalds and Junio C Hamano

 */

#include "builtin.h"

#include "advice.h"

#include "config.h"

#include "environment.h"

#include "gettext.h"

#include "hash.h"

#include "hex.h"

#include "lockfile.h"

#include "object.h"

#include "pretty.h"

#include "refs.h"

#include "diff.h"

#include "diffcore.h"

#include "tree.h"

#include "branch.h"

#include "object-name.h"

#include "parse-options.h"

#include "path.h"

#include "unpack-trees.h"

#include "cache-tree.h"

#include "setup.h"

#include "sparse-index.h"

#include "submodule.h"

#include "trace.h"

#include "trace2.h"

#include "dir.h"

#include "add-interactive.h"

#define REFRESH_INDEX_DELAY_WARNING_IN_MS (2 * 1000)

static const char * const git_reset_usage[] = {

  N_("git reset [--mixed | --soft | --hard | --merge | --keep] [-q] [<commit>]"),

  N_("git reset [-q] [<tree-ish>] [--] <pathspec>..."),

  N_("git reset [-q] [--pathspec-from-file [--pathspec-file-nul]] [<tree-ish>]"),

  N_("git reset --patch [<tree-ish>] [--] [<pathspec>...]"),

  NULL

};

enum reset_type { MIXED, SOFT, HARD, MERGE, KEEP, NONE };

static const char *reset_type_names[] = {

  N_("mixed"), N_("soft"), N_("hard"), N_("merge"), N_("keep"), NULL

};

static inline int is_merge(void)

{

  return !access(git_path_merge_head(the_repository), F_OK);

}

static int reset_index(const char *ref, const struct object_id *oid, int reset_type, int quiet)

{

  int i, nr = 0;

  struct tree_desc desc[2];

  struct tree *tree;

  struct unpack_trees_options opts;

  int ret = -1;

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

  opts.head_idx = 1;

  opts.src_index = the_repository->index;

  opts.dst_index = the_repository->index;

  opts.fn = oneway_merge;

  opts.merge = 1;

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

  if (!quiet)

    opts.verbose_update = 1;

  switch (reset_type) {

  case KEEP:

  case MERGE:

    opts.update = 1;

    opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */

    break;

  case HARD:

    opts.update = 1;

    opts.reset = UNPACK_RESET_OVERWRITE_UNTRACKED;

    opts.skip_cache_tree_update = 1;

    break;

  case MIXED:

    opts.reset = UNPACK_RESET_PROTECT_UNTRACKED;

    opts.skip_cache_tree_update = 1;

    /* but opts.update=0, so working tree not updated */

    break;

  default:

    BUG("invalid reset_type passed to reset_index");

  }

  repo_read_index_unmerged(the_repository);

  if (reset_type == KEEP) {

    struct object_id head_oid;

    if (repo_get_oid(the_repository, "HEAD", &head_oid))

      return error(_("You do not have a valid HEAD."));

    if (!fill_tree_descriptor(the_repository, desc + nr, &head_oid))

      return error(_("Failed to find tree of HEAD."));

    nr++;

    opts.fn = twoway_merge;

  }

  if (!fill_tree_descriptor(the_repository, desc + nr, oid)) {

    error(_("Failed to find tree of %s."), oid_to_hex(oid));

    goto out;

  }

  nr++;

  if (unpack_trees(nr, desc, &opts))

    goto out;

  if (reset_type == MIXED || reset_type == HARD) {

    tree = parse_tree_indirect(oid);

    if (!tree) {

      error(_("unable to read tree (%s)"), oid_to_hex(oid));

      goto out;

    }

    prime_cache_tree(the_repository, the_repository->index, tree);

  }

  ret = 0;

out:

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

    free((void *)desc[i].buffer);

  return ret;

}

static void print_new_head_line(struct commit *commit)

{

  struct strbuf buf = STRBUF_INIT;

  printf(_("HEAD is now at %s"),

    repo_find_unique_abbrev(the_repository, &commit->object.oid, DEFAULT_ABBREV));

  pp_commit_easy(CMIT_FMT_ONELINE, commit, &buf);

  if (buf.len > 0)

    printf(" %s", buf.buf);

  putchar('\n');

  strbuf_release(&buf);

}

static void update_index_from_diff(struct diff_queue_struct *q,

           struct diff_options *opt UNUSED,

           void *data)

{

  int i;

  int intent_to_add = *(int *)data;

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

    int pos;

    struct diff_filespec *one = q->queue[i]->one;

    int is_in_reset_tree = one->mode && !is_null_oid(&one->oid);

    struct cache_entry *ce;

    if (!is_in_reset_tree && !intent_to_add) {

      remove_file_from_index(the_repository->index, one->path);

      continue;

    }

    ce = make_cache_entry(the_repository->index, one->mode, &one->oid, one->path,

              0, 0);

    /*

     * If the file 1) corresponds to an existing index entry with

     * skip-worktree set, or 2) does not exist in the index but is

     * outside the sparse checkout definition, add a skip-worktree bit

     * to the new index entry. Note that a sparse index will be expanded

     * if this entry is outside the sparse cone - this is necessary

     * to properly construct the reset sparse directory.

     */

    pos = index_name_pos(the_repository->index, one->path, strlen(one->path));

    if ((pos >= 0 && ce_skip_worktree(the_repository->index->cache[pos])) ||

        (pos < 0 && !path_in_sparse_checkout(one->path, the_repository->index)))

      ce->ce_flags |= CE_SKIP_WORKTREE;

    if (!ce)

      die(_("make_cache_entry failed for path '%s'"),

          one->path);

    if (!is_in_reset_tree) {

      ce->ce_flags |= CE_INTENT_TO_ADD;

      set_object_name_for_intent_to_add_entry(ce);

    }

    add_index_entry(the_repository->index, ce,

        ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);

  }

}

static int read_from_tree(const struct pathspec *pathspec,

        struct object_id *tree_oid,

        int intent_to_add)

{

  struct diff_options opt;

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

  copy_pathspec(&opt.pathspec, pathspec);

  opt.output_format = DIFF_FORMAT_CALLBACK;

  opt.format_callback = update_index_from_diff;

  opt.format_callback_data = &intent_to_add;

  opt.flags.override_submodule_config = 1;

  opt.flags.recursive = 1;

  opt.repo = the_repository;

  opt.change = diff_change;

  opt.add_remove = diff_addremove;

  if (pathspec->nr && pathspec_needs_expanded_index(the_repository->index, pathspec))

    ensure_full_index(the_repository->index);

  if (do_diff_cache(tree_oid, &opt))

    return 1;

  diffcore_std(&opt);

  diff_flush(&opt);

  return 0;

}

static void set_reflog_message(struct strbuf *sb, const char *action,

             const char *rev)

{

  const char *rla = getenv("GIT_REFLOG_ACTION");

  strbuf_reset(sb);

  if (rla)

    strbuf_addf(sb, "%s: %s", rla, action);

  else if (rev)

    strbuf_addf(sb, "reset: moving to %s", rev);

  else

    strbuf_addf(sb, "reset: %s", action);

}

static void die_if_unmerged_cache(int reset_type)

{

  if (is_merge() || unmerged_index(the_repository->index))

    die(_("Cannot do a %s reset in the middle of a merge."),

        _(reset_type_names[reset_type]));

}

static void parse_args(struct pathspec *pathspec,

           const char **argv, const char *prefix,

           int patch_mode,

           const char **rev_ret)

{

  const char *rev = "HEAD";

  struct object_id unused;

  /*

   * Possible arguments are:

   *

   * git reset [-opts] [<rev>]

   * git reset [-opts] <tree> [<paths>...]

   * git reset [-opts] <tree> -- [<paths>...]

   * git reset [-opts] -- [<paths>...]

   * git reset [-opts] <paths>...

   *

   * At this point, argv points immediately after [-opts].

   */

  if (argv[0]) {

    if (!strcmp(argv[0], "--")) {

      argv++; /* reset to HEAD, possibly with paths */

    } else if (argv[1] && !strcmp(argv[1], "--")) {

      rev = argv[0];

      argv += 2;

    }

    /*

     * Otherwise, argv[0] could be either <rev> or <paths> and

     * has to be unambiguous. If there is a single argument, it

     * can not be a tree

     */

    else if ((!argv[1] && !repo_get_oid_committish(the_repository, argv[0], &unused)) ||

       (argv[1] && !repo_get_oid_treeish(the_repository, argv[0], &unused))) {

      /*

       * Ok, argv[0] looks like a commit/tree; it should not

       * be a filename.

       */

      verify_non_filename(prefix, argv[0]);

      rev = *argv++;

    } else {

      /* Otherwise we treat this as a filename */

      verify_filename(prefix, argv[0], 1);

    }

  }

  /* treat '@' as a shortcut for 'HEAD' */

  *rev_ret = !strcmp("@", rev) ? "HEAD" : rev;

  parse_pathspec(pathspec, 0,

           PATHSPEC_PREFER_FULL |

           (patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0),

           prefix, argv);

}

static int reset_refs(const char *rev, const struct object_id *oid)

{

  int update_ref_status;

  struct strbuf msg = STRBUF_INIT;

  struct object_id *orig = NULL, oid_orig,

    *old_orig = NULL, oid_old_orig;

  if (!repo_get_oid(the_repository, "ORIG_HEAD", &oid_old_orig))

    old_orig = &oid_old_orig;

  if (!repo_get_oid(the_repository, "HEAD", &oid_orig)) {

    orig = &oid_orig;

    set_reflog_message(&msg, "updating ORIG_HEAD", NULL);

    refs_update_ref(get_main_ref_store(the_repository), msg.buf,

        "ORIG_HEAD", orig, old_orig, 0,

        UPDATE_REFS_MSG_ON_ERR);

  } else if (old_orig)

    refs_delete_ref(get_main_ref_store(the_repository), NULL,

        "ORIG_HEAD", old_orig, 0);

  set_reflog_message(&msg, "updating HEAD", rev);

  update_ref_status = refs_update_ref(get_main_ref_store(the_repository),

              msg.buf, "HEAD", oid, orig, 0,

              UPDATE_REFS_MSG_ON_ERR);

  strbuf_release(&msg);

  return update_ref_status;

}

static int git_reset_config(const char *var, const char *value,

          const struct config_context *ctx, void *cb)

{

  if (!strcmp(var, "submodule.recurse"))

    return git_default_submodule_config(var, value, cb);

  return git_default_config(var, value, ctx, cb);

}

int cmd_reset(int argc, const char **argv, const char *prefix)

{

  int reset_type = NONE, update_ref_status = 0, quiet = 0;

  int no_refresh = 0;

  int patch_mode = 0, pathspec_file_nul = 0, unborn;

  const char *rev;

  char *pathspec_from_file = NULL;

  struct object_id oid;

  struct pathspec pathspec;

  int intent_to_add = 0;

  const struct option options[] = {

    OPT__QUIET(&quiet, N_("be quiet, only report errors")),

    OPT_BOOL(0, "no-refresh", &no_refresh,

        N_("skip refreshing the index after reset")),

    OPT_SET_INT_F(0, "mixed", &reset_type,

            N_("reset HEAD and index"),

            MIXED, PARSE_OPT_NONEG),

    OPT_SET_INT_F(0, "soft", &reset_type,

            N_("reset only HEAD"),

            SOFT, PARSE_OPT_NONEG),

    OPT_SET_INT_F(0, "hard", &reset_type,

            N_("reset HEAD, index and working tree"),

            HARD, PARSE_OPT_NONEG),

    OPT_SET_INT_F(0, "merge", &reset_type,

            N_("reset HEAD, index and working tree"),

            MERGE, PARSE_OPT_NONEG),

    OPT_SET_INT_F(0, "keep", &reset_type,

            N_("reset HEAD but keep local changes"),

            KEEP, PARSE_OPT_NONEG),

    OPT_CALLBACK_F(0, "recurse-submodules", NULL,

             "reset", "control recursive updating of submodules",

             PARSE_OPT_OPTARG,

             option_parse_recurse_submodules_worktree_updater),

    OPT_BOOL('p', "patch", &patch_mode, N_("select hunks interactively")),

    OPT_BOOL('N', "intent-to-add", &intent_to_add,

        N_("record only the fact that removed paths will be added later")),

    OPT_PATHSPEC_FROM_FILE(&pathspec_from_file),

    OPT_PATHSPEC_FILE_NUL(&pathspec_file_nul),

    OPT_END()

  };

  git_config(git_reset_config, NULL);

  argc = parse_options(argc, argv, prefix, options, git_reset_usage,

            PARSE_OPT_KEEP_DASHDASH);

  parse_args(&pathspec, argv, prefix, patch_mode, &rev);

  if (pathspec_from_file) {

    if (patch_mode)

      die(_("options '%s' and '%s' cannot be used together"), "--pathspec-from-file", "--patch");

    if (pathspec.nr)

      die(_("'%s' and pathspec arguments cannot be used together"), "--pathspec-from-file");

    parse_pathspec_file(&pathspec, 0,

            PATHSPEC_PREFER_FULL,

            prefix, pathspec_from_file, pathspec_file_nul);

  } else if (pathspec_file_nul) {

    die(_("the option '%s' requires '%s'"), "--pathspec-file-nul", "--pathspec-from-file");

  }

  unborn = !strcmp(rev, "HEAD") && repo_get_oid(the_repository, "HEAD",

                  &oid);

  if (unborn) {

    /* reset on unborn branch: treat as reset to empty tree */

    oidcpy(&oid, the_hash_algo->empty_tree);

  } else if (!pathspec.nr && !patch_mode) {

    struct commit *commit;

    if (repo_get_oid_committish(the_repository, rev, &oid))

      die(_("Failed to resolve '%s' as a valid revision."), rev);

    commit = lookup_commit_reference(the_repository, &oid);

    if (!commit)

      die(_("Could not parse object '%s'."), rev);

    oidcpy(&oid, &commit->object.oid);

  } else {

    struct tree *tree;

    if (repo_get_oid_treeish(the_repository, rev, &oid))

      die(_("Failed to resolve '%s' as a valid tree."), rev);

    tree = parse_tree_indirect(&oid);

    if (!tree)

      die(_("Could not parse object '%s'."), rev);

    oidcpy(&oid, &tree->object.oid);

  }

  if (patch_mode) {

    if (reset_type != NONE)

      die(_("options '%s' and '%s' cannot be used together"), "--patch", "--{hard,mixed,soft}");

    trace2_cmd_mode("patch-interactive");

    update_ref_status = !!run_add_p(the_repository, ADD_P_RESET, rev,

           &pathspec);

    goto cleanup;

  }

  /* git reset tree [--] paths... can be used to

   * load chosen paths from the tree into the index without

   * affecting the working tree nor HEAD. */

  if (pathspec.nr) {

    if (reset_type == MIXED)

      warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));

    else if (reset_type != NONE)

      die(_("Cannot do %s reset with paths."),

          _(reset_type_names[reset_type]));

  }

  if (reset_type == NONE)

    reset_type = MIXED; /* by default */

  if (pathspec.nr)

    trace2_cmd_mode("path");

  else

    trace2_cmd_mode(reset_type_names[reset_type]);

  if (reset_type != SOFT && (reset_type != MIXED || get_git_work_tree()))

    setup_work_tree();

  if (reset_type == MIXED && is_bare_repository())

    die(_("%s reset is not allowed in a bare repository"),

        _(reset_type_names[reset_type]));

  if (intent_to_add && reset_type != MIXED)

    die(_("the option '%s' requires '%s'"), "-N", "--mixed");

  prepare_repo_settings(the_repository);

  the_repository->settings.command_requires_full_index = 0;

  if (repo_read_index(the_repository) < 0)

    die(_("index file corrupt"));

  /* Soft reset does not touch the index file nor the working tree

   * at all, but requires them in a good order.  Other resets reset

   * the index file to the tree object we are switching to. */

  if (reset_type == SOFT || reset_type == KEEP)

    die_if_unmerged_cache(reset_type);

  if (reset_type != SOFT) {

    struct lock_file lock = LOCK_INIT;

    repo_hold_locked_index(the_repository, &lock,

               LOCK_DIE_ON_ERROR);

    if (reset_type == MIXED) {

      int flags = quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN;

      if (read_from_tree(&pathspec, &oid, intent_to_add)) {

        update_ref_status = 1;

        goto cleanup;

      }

      the_repository->index->updated_skipworktree = 1;

      if (!no_refresh && get_git_work_tree()) {

        uint64_t t_begin, t_delta_in_ms;

        t_begin = getnanotime();

        refresh_index(the_repository->index, flags, NULL, NULL,

                _("Unstaged changes after reset:"));

        t_delta_in_ms = (getnanotime() - t_begin) / 1000000;

        if (!quiet && advice_enabled(ADVICE_RESET_NO_REFRESH_WARNING) && t_delta_in_ms > REFRESH_INDEX_DELAY_WARNING_IN_MS) {

          advise(_("It took %.2f seconds to refresh the index after reset.  You can use\n"

             "'--no-refresh' to avoid this."), t_delta_in_ms / 1000.0);

        }

      }

    } else {

      struct object_id dummy;

      char *ref = NULL;

      int err;

      repo_dwim_ref(the_repository, rev, strlen(rev),

              &dummy, &ref, 0);

      if (ref && !starts_with(ref, "refs/"))

        FREE_AND_NULL(ref);

      err = reset_index(ref, &oid, reset_type, quiet);

      if (reset_type == KEEP && !err)

        err = reset_index(ref, &oid, MIXED, quiet);

      if (err)

        die(_("Could not reset index file to revision '%s'."), rev);

      free(ref);

    }

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

      die(_("Could not write new index file."));

  }

  if (!pathspec.nr && !unborn) {

    /* Any resets without paths update HEAD to the head being

     * switched to, saving the previous head in ORIG_HEAD before. */

    update_ref_status = reset_refs(rev, &oid);

    if (reset_type == HARD && !update_ref_status && !quiet)

      print_new_head_line(lookup_commit_reference(the_repository, &oid));

  }

  if (!pathspec.nr)

    remove_branch_state(the_repository, 0);

  discard_index(the_repository->index);

cleanup:

  clear_pathspec(&pathspec);

  free(pathspec_from_file);

  return update_ref_status;

}