/*

 * Builtin "git replace"

 *

 * Copyright (c) 2008 Christian Couder <chriscool@tuxfamily.org>

 *

 * Based on builtin/tag.c by Kristian Høgsberg <krh@redhat.com>

 * and Carlos Rica <jasampler@gmail.com> that was itself based on

 * git-tag.sh and mktag.c by Linus Torvalds.

 */

#include "builtin.h"

#include "config.h"

#include "editor.h"

#include "environment.h"

#include "gettext.h"

#include "hex.h"

#include "refs.h"

#include "parse-options.h"

#include "path.h"

#include "run-command.h"

#include "object-file.h"

#include "object-name.h"

#include "object-store-ll.h"

#include "replace-object.h"

#include "repository.h"

#include "tag.h"

#include "wildmatch.h"

static const char * const git_replace_usage[] = {

  N_("git replace [-f] <object> <replacement>"),

  N_("git replace [-f] --edit <object>"),

  N_("git replace [-f] --graft <commit> [<parent>...]"),

  "git replace [-f] --convert-graft-file",

  N_("git replace -d <object>..."),

  N_("git replace [--format=<format>] [-l [<pattern>]]"),

  NULL

};

enum replace_format {

  REPLACE_FORMAT_SHORT,

  REPLACE_FORMAT_MEDIUM,

  REPLACE_FORMAT_LONG

};

struct show_data {

  struct repository *repo;

  const char *pattern;

  enum replace_format format;

};

static int show_reference(const char *refname,

        const char *referent UNUSED,

        const struct object_id *oid,

        int flag UNUSED, void *cb_data)

{

  struct show_data *data = cb_data;

  if (!wildmatch(data->pattern, refname, 0)) {

    if (data->format == REPLACE_FORMAT_SHORT)

      printf("%s\n", refname);

    else if (data->format == REPLACE_FORMAT_MEDIUM)

      printf("%s -> %s\n", refname, oid_to_hex(oid));

    else { /* data->format == REPLACE_FORMAT_LONG */

      struct object_id object;

      enum object_type obj_type, repl_type;

      if (repo_get_oid(data->repo, refname, &object))

        return error(_("failed to resolve '%s' as a valid ref"), refname);

      obj_type = oid_object_info(data->repo, &object, NULL);

      repl_type = oid_object_info(data->repo, oid, NULL);

      printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),

             oid_to_hex(oid), type_name(repl_type));

    }

  }

  return 0;

}

static int list_replace_refs(const char *pattern, const char *format)

{

  struct show_data data;

  data.repo = the_repository;

  if (!pattern)

    pattern = "*";

  data.pattern = pattern;

  if (format == NULL || *format == '\0' || !strcmp(format, "short"))

    data.format = REPLACE_FORMAT_SHORT;

  else if (!strcmp(format, "medium"))

    data.format = REPLACE_FORMAT_MEDIUM;

  else if (!strcmp(format, "long"))

    data.format = REPLACE_FORMAT_LONG;

  /*

   * Please update _git_replace() in git-completion.bash when

   * you add new format

   */

  else

    return error(_("invalid replace format '%s'\n"

             "valid formats are 'short', 'medium' and 'long'"),

           format);

  refs_for_each_replace_ref(get_main_ref_store(the_repository),

          show_reference, (void *)&data);

  return 0;

}

typedef int (*each_replace_name_fn)(const char *name, const char *ref,

            const struct object_id *oid);

static int for_each_replace_name(const char **argv, each_replace_name_fn fn)

{

  const char **p, *full_hex;

  struct strbuf ref = STRBUF_INIT;

  size_t base_len;

  int had_error = 0;

  struct object_id oid;

  const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;

  strbuf_addstr(&ref, git_replace_ref_base);

  base_len = ref.len;

  for (p = argv; *p; p++) {

    if (repo_get_oid(the_repository, *p, &oid)) {

      error("failed to resolve '%s' as a valid ref", *p);

      had_error = 1;

      continue;

    }

    strbuf_setlen(&ref, base_len);

    strbuf_addstr(&ref, oid_to_hex(&oid));

    full_hex = ref.buf + base_len;

    if (refs_read_ref(get_main_ref_store(the_repository), ref.buf, &oid)) {

      error(_("replace ref '%s' not found"), full_hex);

      had_error = 1;

      continue;

    }

    if (fn(full_hex, ref.buf, &oid))

      had_error = 1;

  }

  strbuf_release(&ref);

  return had_error;

}

static int delete_replace_ref(const char *name, const char *ref,

            const struct object_id *oid)

{

  if (refs_delete_ref(get_main_ref_store(the_repository), NULL, ref, oid, 0))

    return 1;

  printf_ln(_("Deleted replace ref '%s'"), name);

  return 0;

}

static int check_ref_valid(struct object_id *object,

          struct object_id *prev,

          struct strbuf *ref,

          int force)

{

  const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;

  strbuf_reset(ref);

  strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));

  if (check_refname_format(ref->buf, 0))

    return error(_("'%s' is not a valid ref name"), ref->buf);

  if (refs_read_ref(get_main_ref_store(the_repository), ref->buf, prev))

    oidclr(prev, the_repository->hash_algo);

  else if (!force)

    return error(_("replace ref '%s' already exists"), ref->buf);

  return 0;

}

static int replace_object_oid(const char *object_ref,

             struct object_id *object,

             const char *replace_ref,

             struct object_id *repl,

             int force)

{

  struct object_id prev;

  enum object_type obj_type, repl_type;

  struct strbuf ref = STRBUF_INIT;

  struct ref_transaction *transaction;

  struct strbuf err = STRBUF_INIT;

  int res = 0;

  obj_type = oid_object_info(the_repository, object, NULL);

  repl_type = oid_object_info(the_repository, repl, NULL);

  if (!force && obj_type != repl_type)

    return error(_("Objects must be of the same type.\n"

             "'%s' points to a replaced object of type '%s'\n"

             "while '%s' points to a replacement object of "

             "type '%s'."),

           object_ref, type_name(obj_type),

           replace_ref, type_name(repl_type));

  if (check_ref_valid(object, &prev, &ref, force)) {

    strbuf_release(&ref);

    return -1;

  }

  transaction = ref_store_transaction_begin(get_main_ref_store(the_repository),

              &err);

  if (!transaction ||

      ref_transaction_update(transaction, ref.buf, repl, &prev,

           NULL, NULL, 0, NULL, &err) ||

      ref_transaction_commit(transaction, &err))

    res = error("%s", err.buf);

  ref_transaction_free(transaction);

  strbuf_release(&ref);

  return res;

}

static int replace_object(const char *object_ref, const char *replace_ref, int force)

{

  struct object_id object, repl;

  if (repo_get_oid(the_repository, object_ref, &object))

    return error(_("failed to resolve '%s' as a valid ref"),

           object_ref);

  if (repo_get_oid(the_repository, replace_ref, &repl))

    return error(_("failed to resolve '%s' as a valid ref"),

           replace_ref);

  return replace_object_oid(object_ref, &object, replace_ref, &repl, force);

}

/*

 * Write the contents of the object named by "sha1" to the file "filename".

 * If "raw" is true, then the object's raw contents are printed according to

 * "type". Otherwise, we pretty-print the contents for human editing.

 */

static int export_object(const struct object_id *oid, enum object_type type,

        int raw, const char *filename)

{

  struct child_process cmd = CHILD_PROCESS_INIT;

  int fd;

  fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);

  if (fd < 0)

    return error_errno(_("unable to open %s for writing"), filename);

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

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

  if (raw)

    strvec_push(&cmd.args, type_name(type));

  else

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

  strvec_push(&cmd.args, oid_to_hex(oid));

  cmd.git_cmd = 1;

  cmd.out = fd;

  if (run_command(&cmd))

    return error(_("cat-file reported failure"));

  return 0;

}

/*

 * Read a previously-exported (and possibly edited) object back from "filename",

 * interpreting it as "type", and writing the result to the object database.

 * The sha1 of the written object is returned via sha1.

 */

static int import_object(struct object_id *oid, enum object_type type,

        int raw, const char *filename)

{

  int fd;

  fd = open(filename, O_RDONLY);

  if (fd < 0)

    return error_errno(_("unable to open %s for reading"), filename);

  if (!raw && type == OBJ_TREE) {

    struct child_process cmd = CHILD_PROCESS_INIT;

    struct strbuf result = STRBUF_INIT;

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

    cmd.git_cmd = 1;

    cmd.in = fd;

    cmd.out = -1;

    if (start_command(&cmd)) {

      close(fd);

      return error(_("unable to spawn mktree"));

    }

    if (strbuf_read(&result, cmd.out, the_hash_algo->hexsz + 1) < 0) {

      error_errno(_("unable to read from mktree"));

      close(fd);

      close(cmd.out);

      return -1;

    }

    close(cmd.out);

    if (finish_command(&cmd)) {

      strbuf_release(&result);

      return error(_("mktree reported failure"));

    }

    if (get_oid_hex(result.buf, oid) < 0) {

      strbuf_release(&result);

      return error(_("mktree did not return an object name"));

    }

    strbuf_release(&result);

  } else {

    struct stat st;

    int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;

    if (fstat(fd, &st) < 0) {

      error_errno(_("unable to fstat %s"), filename);

      close(fd);

      return -1;

    }

    if (index_fd(the_repository->index, oid, fd, &st, type, NULL, flags) < 0)

      return error(_("unable to write object to database"));

    /* index_fd close()s fd for us */

  }

  /*

   * No need to close(fd) here; both run-command and index-fd

   * will have done it for us.

   */

  return 0;

}

static int edit_and_replace(const char *object_ref, int force, int raw)

{

  char *tmpfile;

  enum object_type type;

  struct object_id old_oid, new_oid, prev;

  struct strbuf ref = STRBUF_INIT;

  if (repo_get_oid(the_repository, object_ref, &old_oid) < 0)

    return error(_("not a valid object name: '%s'"), object_ref);

  type = oid_object_info(the_repository, &old_oid, NULL);

  if (type < 0)

    return error(_("unable to get object type for %s"),

           oid_to_hex(&old_oid));

  if (check_ref_valid(&old_oid, &prev, &ref, force)) {

    strbuf_release(&ref);

    return -1;

  }

  strbuf_release(&ref);

  tmpfile = git_pathdup("REPLACE_EDITOBJ");

  if (export_object(&old_oid, type, raw, tmpfile)) {

    free(tmpfile);

    return -1;

  }

  if (launch_editor(tmpfile, NULL, NULL) < 0) {

    free(tmpfile);

    return error(_("editing object file failed"));

  }

  if (import_object(&new_oid, type, raw, tmpfile)) {

    free(tmpfile);

    return -1;

  }

  free(tmpfile);

  if (oideq(&old_oid, &new_oid))

    return error(_("new object is the same as the old one: '%s'"), oid_to_hex(&old_oid));

  return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);

}

static int replace_parents(struct strbuf *buf, int argc, const char **argv)

{

  struct strbuf new_parents = STRBUF_INIT;

  const char *parent_start, *parent_end;

  int i;

  const unsigned hexsz = the_hash_algo->hexsz;

  /* find existing parents */

  parent_start = buf->buf;

  parent_start += hexsz + 6; /* "tree " + "hex sha1" + "\n" */

  parent_end = parent_start;

  while (starts_with(parent_end, "parent "))

    parent_end += hexsz + 8; /* "parent " + "hex sha1" + "\n" */

  /* prepare new parents */

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

    struct object_id oid;

    struct commit *commit;

    if (repo_get_oid(the_repository, argv[i], &oid) < 0) {

      strbuf_release(&new_parents);

      return error(_("not a valid object name: '%s'"),

             argv[i]);

    }

    commit = lookup_commit_reference(the_repository, &oid);

    if (!commit) {

      strbuf_release(&new_parents);

      return error(_("could not parse %s as a commit"), argv[i]);

    }

    strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&commit->object.oid));

  }

  /* replace existing parents with new ones */

  strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,

          new_parents.buf, new_parents.len);

  strbuf_release(&new_parents);

  return 0;

}

struct check_mergetag_data {

  int argc;

  const char **argv;

};

static int check_one_mergetag(struct commit *commit UNUSED,

             struct commit_extra_header *extra,

             void *data)

{

  struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;

  const char *ref = mergetag_data->argv[0];

  struct object_id tag_oid;

  struct tag *tag;

  int i;

  hash_object_file(the_hash_algo, extra->value, extra->len,

       OBJ_TAG, &tag_oid);

  tag = lookup_tag(the_repository, &tag_oid);

  if (!tag)

    return error(_("bad mergetag in commit '%s'"), ref);

  if (parse_tag_buffer(the_repository, tag, extra->value, extra->len))

    return error(_("malformed mergetag in commit '%s'"), ref);

  /* iterate over new parents */

  for (i = 1; i < mergetag_data->argc; i++) {

    struct object_id oid;

    if (repo_get_oid(the_repository, mergetag_data->argv[i], &oid) < 0)

      return error(_("not a valid object name: '%s'"),

             mergetag_data->argv[i]);

    if (oideq(get_tagged_oid(tag), &oid))

      return 0; /* found */

  }

  return error(_("original commit '%s' contains mergetag '%s' that is "

           "discarded; use --edit instead of --graft"), ref,

         oid_to_hex(&tag_oid));

}

static int check_mergetags(struct commit *commit, int argc, const char **argv)

{

  struct check_mergetag_data mergetag_data;

  mergetag_data.argc = argc;

  mergetag_data.argv = argv;

  return for_each_mergetag(check_one_mergetag, commit, &mergetag_data);

}

static int create_graft(int argc, const char **argv, int force, int gentle)

{

  struct object_id old_oid, new_oid;

  const char *old_ref = argv[0];

  struct commit *commit;

  struct strbuf buf = STRBUF_INIT;

  const char *buffer;

  unsigned long size;

  if (repo_get_oid(the_repository, old_ref, &old_oid) < 0)

    return error(_("not a valid object name: '%s'"), old_ref);

  commit = lookup_commit_reference(the_repository, &old_oid);

  if (!commit)

    return error(_("could not parse %s"), old_ref);

  buffer = repo_get_commit_buffer(the_repository, commit, &size);

  strbuf_add(&buf, buffer, size);

  repo_unuse_commit_buffer(the_repository, commit, buffer);

  if (replace_parents(&buf, argc - 1, &argv[1]) < 0) {

    strbuf_release(&buf);

    return -1;

  }

  if (remove_signature(&buf)) {

    warning(_("the original commit '%s' has a gpg signature"), old_ref);

    warning(_("the signature will be removed in the replacement commit!"));

  }

  if (check_mergetags(commit, argc, argv)) {

    strbuf_release(&buf);

    return -1;

  }

  if (write_object_file(buf.buf, buf.len, OBJ_COMMIT, &new_oid)) {

    strbuf_release(&buf);

    return error(_("could not write replacement commit for: '%s'"),

           old_ref);

  }

  strbuf_release(&buf);

  if (oideq(&commit->object.oid, &new_oid)) {

    if (gentle) {

      warning(_("graft for '%s' unnecessary"),

        oid_to_hex(&commit->object.oid));

      return 0;

    }

    return error(_("new commit is the same as the old one: '%s'"),

           oid_to_hex(&commit->object.oid));

  }

  return replace_object_oid(old_ref, &commit->object.oid,

          "replacement", &new_oid, force);

}

static int convert_graft_file(int force)

{

  const char *graft_file = get_graft_file(the_repository);

  FILE *fp = fopen_or_warn(graft_file, "r");

  struct strbuf buf = STRBUF_INIT, err = STRBUF_INIT;

  struct strvec args = STRVEC_INIT;

  if (!fp)

    return -1;

  no_graft_file_deprecated_advice = 1;

  while (strbuf_getline(&buf, fp) != EOF) {

    if (*buf.buf == '#')

      continue;

    strvec_split(&args, buf.buf);

    if (args.nr && create_graft(args.nr, args.v, force, 1))

      strbuf_addf(&err, "\n\t%s", buf.buf);

    strvec_clear(&args);

  }

  fclose(fp);

  strbuf_release(&buf);

  if (!err.len)

    return unlink_or_warn(graft_file);

  warning(_("could not convert the following graft(s):\n%s"), err.buf);

  strbuf_release(&err);

  return -1;

}

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

{

  int force = 0;

  int raw = 0;

  const char *format = NULL;

  enum {

    MODE_UNSPECIFIED = 0,

    MODE_LIST,

    MODE_DELETE,

    MODE_EDIT,

    MODE_GRAFT,

    MODE_CONVERT_GRAFT_FILE,

    MODE_REPLACE

  } cmdmode = MODE_UNSPECIFIED;

  struct option options[] = {

    OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),

    OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),

    OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),

    OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),

    OPT_CMDMODE(0, "convert-graft-file", &cmdmode, N_("convert existing graft file"), MODE_CONVERT_GRAFT_FILE),

    OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),

         PARSE_OPT_NOCOMPLETE),

    OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),

    OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),

    OPT_END()

  };

  disable_replace_refs();

  git_config(git_default_config, NULL);

  argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);

  if (!cmdmode)

    cmdmode = argc ? MODE_REPLACE : MODE_LIST;

  if (format && cmdmode != MODE_LIST)

    usage_msg_opt(_("--format cannot be used when not listing"),

            git_replace_usage, options);

  if (force &&

      cmdmode != MODE_REPLACE &&

      cmdmode != MODE_EDIT &&

      cmdmode != MODE_GRAFT &&

      cmdmode != MODE_CONVERT_GRAFT_FILE)

    usage_msg_opt(_("-f only makes sense when writing a replacement"),

            git_replace_usage, options);

  if (raw && cmdmode != MODE_EDIT)

    usage_msg_opt(_("--raw only makes sense with --edit"),

            git_replace_usage, options);

  switch (cmdmode) {

  case MODE_DELETE:

    if (argc < 1)

      usage_msg_opt(_("-d needs at least one argument"),

              git_replace_usage, options);

    return for_each_replace_name(argv, delete_replace_ref);

  case MODE_REPLACE:

    if (argc != 2)

      usage_msg_opt(_("bad number of arguments"),

              git_replace_usage, options);

    return replace_object(argv[0], argv[1], force);

  case MODE_EDIT:

    if (argc != 1)

      usage_msg_opt(_("-e needs exactly one argument"),

              git_replace_usage, options);

    return edit_and_replace(argv[0], force, raw);

  case MODE_GRAFT:

    if (argc < 1)

      usage_msg_opt(_("-g needs at least one argument"),

              git_replace_usage, options);

    return create_graft(argc, argv, force, 0);

  case MODE_CONVERT_GRAFT_FILE:

    if (argc != 0)

      usage_msg_opt(_("--convert-graft-file takes no argument"),

              git_replace_usage, options);

    return !!convert_graft_file(force);

  case MODE_LIST:

    if (argc > 1)

      usage_msg_opt(_("only one pattern can be given with -l"),

              git_replace_usage, options);

    return list_replace_refs(argv[0], format);

  default:

    BUG("invalid cmdmode %d", (int)cmdmode);

  }

}