/*

 * GIT - The information manager from hell

 *

 * Copyright (C) Linus Torvalds, 2005

 */

#include "builtin.h"

#include "config.h"

#include "gettext.h"

#include "hex.h"

#include "lockfile.h"

#include "object.h"

#include "object-name.h"

#include "tree.h"

#include "tree-walk.h"

#include "cache-tree.h"

#include "unpack-trees.h"

#include "parse-options.h"

#include "repository.h"

#include "resolve-undo.h"

#include "setup.h"

#include "sparse-index.h"

#include "submodule.h"

static int nr_trees;

static int read_empty;

static struct tree *trees[MAX_UNPACK_TREES];

static int list_tree(struct object_id *oid)

{

  struct tree *tree;

  if (nr_trees >= MAX_UNPACK_TREES)

    die("I cannot read more than %d trees", MAX_UNPACK_TREES);

  tree = parse_tree_indirect(oid);

  if (!tree)

    return -1;

  trees[nr_trees++] = tree;

  return 0;

}

static const char * const read_tree_usage[] = {

  N_("git read-tree [(-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>)\n"

     "              [-u | -i]] [--index-output=<file>] [--no-sparse-checkout]\n"

     "              (--empty | <tree-ish1> [<tree-ish2> [<tree-ish3>]])"),

  NULL

};

static int index_output_cb(const struct option *opt UNUSED, const char *arg,

         int unset)

{

  BUG_ON_OPT_NEG(unset);

  set_alternate_index_output(arg);

  return 0;

}

static int exclude_per_directory_cb(const struct option *opt, const char *arg,

            int unset)

{

  struct unpack_trees_options *opts;

  BUG_ON_OPT_NEG(unset);

  opts = (struct unpack_trees_options *)opt->value;

  if (!opts->update)

    die("--exclude-per-directory is meaningless unless -u");

  if (strcmp(arg, ".gitignore"))

    die("--exclude-per-directory argument must be .gitignore");

  return 0;

}

static void debug_stage(const char *label, const struct cache_entry *ce,

      struct unpack_trees_options *o)

{

  printf("%s ", label);

  if (!ce)

    printf("(missing)\n");

  else if (ce == o->df_conflict_entry)

    printf("(conflict)\n");

  else

    printf("%06o #%d %s %.8s\n",

           ce->ce_mode, ce_stage(ce), ce->name,

           oid_to_hex(&ce->oid));

}

static int debug_merge(const struct cache_entry * const *stages,

           struct unpack_trees_options *o)

{

  int i;

  printf("* %d-way merge\n", o->internal.merge_size);

  debug_stage("index", stages[0], o);

  for (i = 1; i <= o->internal.merge_size; i++) {

    char buf[24];

    xsnprintf(buf, sizeof(buf), "ent#%d", i);

    debug_stage(buf, stages[i], o);

  }

  return 0;

}

static int git_read_tree_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_read_tree(int argc, const char **argv, const char *cmd_prefix)

{

  int i, stage = 0;

  struct object_id oid;

  struct tree_desc t[MAX_UNPACK_TREES];

  struct unpack_trees_options opts;

  int prefix_set = 0;

  struct lock_file lock_file = LOCK_INIT;

  const struct option read_tree_options[] = {

    OPT__SUPER_PREFIX(&opts.super_prefix),

    OPT_CALLBACK_F(0, "index-output", NULL, N_("file"),

      N_("write resulting index to <file>"),

      PARSE_OPT_NONEG, index_output_cb),

    OPT_BOOL(0, "empty", &read_empty,

          N_("only empty the index")),

    OPT__VERBOSE(&opts.verbose_update, N_("be verbose")),

    OPT_GROUP(N_("Merging")),

    OPT_BOOL('m', NULL, &opts.merge,

       N_("perform a merge in addition to a read")),

    OPT_BOOL(0, "trivial", &opts.trivial_merges_only,

       N_("3-way merge if no file level merging required")),

    OPT_BOOL(0, "aggressive", &opts.aggressive,

       N_("3-way merge in presence of adds and removes")),

    OPT_BOOL(0, "reset", &opts.reset,

       N_("same as -m, but discard unmerged entries")),

    { OPTION_STRING, 0, "prefix", &opts.prefix, N_("<subdirectory>/"),

      N_("read the tree into the index under <subdirectory>/"),

      PARSE_OPT_NONEG },

    OPT_BOOL('u', NULL, &opts.update,

       N_("update working tree with merge result")),

    OPT_CALLBACK_F(0, "exclude-per-directory", &opts,

      N_("gitignore"),

      N_("allow explicitly ignored files to be overwritten"),

      PARSE_OPT_NONEG, exclude_per_directory_cb),

    OPT_BOOL('i', NULL, &opts.index_only,

       N_("don't check the working tree after merging")),

    OPT__DRY_RUN(&opts.dry_run, N_("don't update the index or the work tree")),

    OPT_BOOL(0, "no-sparse-checkout", &opts.skip_sparse_checkout,

       N_("skip applying sparse checkout filter")),

    OPT_BOOL(0, "debug-unpack", &opts.internal.debug_unpack,

       N_("debug unpack-trees")),

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

          "checkout", "control recursive updating of submodules",

          PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater),

    OPT__QUIET(&opts.quiet, N_("suppress feedback messages")),

    OPT_END()

  };

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

  opts.head_idx = -1;

  opts.src_index = the_repository->index;

  opts.dst_index = the_repository->index;

  git_config(git_read_tree_config, NULL);

  argc = parse_options(argc, argv, cmd_prefix, read_tree_options,

           read_tree_usage, 0);

  prefix_set = opts.prefix ? 1 : 0;

  if (1 < opts.merge + opts.reset + prefix_set)

    die("Which one? -m, --reset, or --prefix?");

  /* Prefix should not start with a directory separator */

  if (opts.prefix && opts.prefix[0] == '/')

    die("Invalid prefix, prefix cannot start with '/'");

  if (opts.reset)

    opts.reset = UNPACK_RESET_OVERWRITE_UNTRACKED;

  prepare_repo_settings(the_repository);

  the_repository->settings.command_requires_full_index = 0;

  repo_hold_locked_index(the_repository, &lock_file, LOCK_DIE_ON_ERROR);

  /*

   * NEEDSWORK

   *

   * The old index should be read anyway even if we're going to

   * destroy all index entries because we still need to preserve

   * certain information such as index version or split-index

   * mode.

   */

  if (opts.reset || opts.merge || opts.prefix) {

    if (repo_read_index_unmerged(the_repository) && (opts.prefix || opts.merge))

      die(_("You need to resolve your current index first"));

    stage = opts.merge = 1;

  }

  resolve_undo_clear_index(the_repository->index);

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

    const char *arg = argv[i];

    if (repo_get_oid(the_repository, arg, &oid))

      die("Not a valid object name %s", arg);

    if (list_tree(&oid) < 0)

      die("failed to unpack tree object %s", arg);

    stage++;

  }

  if (!nr_trees && !read_empty && !opts.merge)

    warning("read-tree: emptying the index with no arguments is deprecated; use --empty");

  else if (nr_trees > 0 && read_empty)

    die("passing trees as arguments contradicts --empty");

  if (1 < opts.index_only + opts.update)

    die("-u and -i at the same time makes no sense");

  if ((opts.update || opts.index_only) && !opts.merge)

    die("%s is meaningless without -m, --reset, or --prefix",

        opts.update ? "-u" : "-i");

  if (opts.update && !opts.reset)

    opts.preserve_ignored = 0;

  /* otherwise, opts.preserve_ignored is irrelevant */

  if (opts.merge && !opts.index_only)

    setup_work_tree();

  if (opts.skip_sparse_checkout)

    ensure_full_index(the_repository->index);

  if (opts.merge) {

    switch (stage - 1) {

    case 0:

      die("you must specify at least one tree to merge");

      break;

    case 1:

      opts.fn = opts.prefix ? bind_merge : oneway_merge;

      break;

    case 2:

      opts.fn = twoway_merge;

      opts.initial_checkout = is_index_unborn(the_repository->index);

      break;

    case 3:

    default:

      opts.fn = threeway_merge;

      break;

    }

    if (stage - 1 >= 3)

      opts.head_idx = stage - 2;

    else

      opts.head_idx = 1;

  }

  if (opts.internal.debug_unpack)

    opts.fn = debug_merge;

  /* If we're going to prime_cache_tree later, skip cache tree update */

  if (nr_trees == 1 && !opts.prefix)

    opts.skip_cache_tree_update = 1;

  cache_tree_free(&the_repository->index->cache_tree);

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

    struct tree *tree = trees[i];

    if (parse_tree(tree) < 0)

      return 128;

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

  }

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

    return 128;

  if (opts.internal.debug_unpack || opts.dry_run)

    return 0; /* do not write the index out */

  /*

   * When reading only one tree (either the most basic form,

   * "-m ent" or "--reset ent" form), we can obtain a fully

   * valid cache-tree because the index must match exactly

   * what came from the tree.

   */

  if (nr_trees == 1 && !opts.prefix)

    prime_cache_tree(the_repository,

         the_repository->index,

         trees[0]);

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

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

  return 0;

}