cat-file.c

/*
 * libgit2 "cat-file" example - shows how to print data from the ODB
 *
 * Written by the libgit2 contributors
 *
 * To the extent possible under law, the author(s) have dedicated all copyright
 * and related and neighboring rights to this software to the public domain
 * worldwide. This software is distributed without any warranty.
 *
 * You should have received a copy of the CC0 Public Domain Dedication along
 * with this software. If not, see
 * <http://creativecommons.org/publicdomain/zero/1.0/>.
 */

#include "common.h"

static void print_signature(const char *header, const git_signature *sig)
{
  char sign;
  int offset, hours, minutes;

  if (!sig)
    return;

  offset = sig->when.offset;
  if (offset < 0) {
    sign = '-';
    offset = -offset;
  } else {
    sign = '+';
  }

  hours   = offset / 60;
  minutes = offset % 60;

  printf("%s %s <%s> %ld %c%02d%02d\n",
       header, sig->name, sig->email, (long)sig->when.time,
       sign, hours, minutes);
}

static void show_blob(const git_blob *blob)
{
  /* ? Does this need crlf filtering? */
  fwrite(git_blob_rawcontent(blob), (size_t)git_blob_rawsize(blob), 1, stdout);
}

static void show_tree(const git_tree *tree)
{
  size_t i, max_i = (int)git_tree_entrycount(tree);
  char oidstr[GIT_OID_SHA1_HEXSIZE + 1];
  const git_tree_entry *te;

  for (i = 0; i < max_i; ++i) {
    te = git_tree_entry_byindex(tree, i);

    git_oid_tostr(oidstr, sizeof(oidstr), git_tree_entry_id(te));

    printf("%06o %s %s\t%s\n",
      git_tree_entry_filemode(te),
      git_object_type2string(git_tree_entry_type(te)),
      oidstr, git_tree_entry_name(te));
  }
}

static void show_commit(const git_commit *commit)
{
  unsigned int i, max_i;
  char oidstr[GIT_OID_SHA1_HEXSIZE + 1];

  git_oid_tostr(oidstr, sizeof(oidstr), git_commit_tree_id(commit));
  printf("tree %s\n", oidstr);

  max_i = (unsigned int)git_commit_parentcount(commit);
  for (i = 0; i < max_i; ++i) {
    git_oid_tostr(oidstr, sizeof(oidstr), git_commit_parent_id(commit, i));
    printf("parent %s\n", oidstr);
  }

  print_signature("author", git_commit_author(commit));
  print_signature("committer", git_commit_committer(commit));

  if (git_commit_message(commit))
    printf("\n%s\n", git_commit_message(commit));
}

static void show_tag(const git_tag *tag)
{
  char oidstr[GIT_OID_SHA1_HEXSIZE + 1];

  git_oid_tostr(oidstr, sizeof(oidstr), git_tag_target_id(tag));;
  printf("object %s\n", oidstr);
  printf("type %s\n", git_object_type2string(git_tag_target_type(tag)));
  printf("tag %s\n", git_tag_name(tag));
  print_signature("tagger", git_tag_tagger(tag));

  if (git_tag_message(tag))
    printf("\n%s\n", git_tag_message(tag));
}

typedef enum {
  SHOW_TYPE = 1,
  SHOW_SIZE = 2,
  SHOW_NONE = 3,
  SHOW_PRETTY = 4
} catfile_mode;

/* Forward declarations for option-parsing helper */
struct catfile_options {
  const char *dir;
  const char *rev;
  catfile_mode action;
  int verbose;
};

static void parse_opts(struct catfile_options *o, int argc, char *argv[]);

int lg2_cat_file(git_repository *repo, int argc, char *argv[])
{
  struct catfile_options o = { ".", NULL, 0, 0 };
  git_object *obj = NULL;
  char oidstr[GIT_OID_SHA1_HEXSIZE + 1];

  parse_opts(&o, argc, argv);

  check_lg2(git_revparse_single(&obj, repo, o.rev),
      "Could not resolve", o.rev);

  if (o.verbose) {
    char oidstr[GIT_OID_SHA1_HEXSIZE + 1];
    git_oid_tostr(oidstr, sizeof(oidstr), git_object_id(obj));

    printf("%s %s\n--\n",
      git_object_type2string(git_object_type(obj)), oidstr);
  }

  switch (o.action) {
  case SHOW_TYPE:
    printf("%s\n", git_object_type2string(git_object_type(obj)));
    break;
  case SHOW_SIZE: {
    git_odb *odb;
    git_odb_object *odbobj;

    check_lg2(git_repository_odb(&odb, repo), "Could not open ODB", NULL);
    check_lg2(git_odb_read(&odbobj, odb, git_object_id(obj)),
      "Could not find obj", NULL);

    printf("%ld\n", (long)git_odb_object_size(odbobj));

    git_odb_object_free(odbobj);
    git_odb_free(odb);
    }
    break;
  case SHOW_NONE:
    /* just want return result */
    break;
  case SHOW_PRETTY:

    switch (git_object_type(obj)) {
    case GIT_OBJECT_BLOB:
      show_blob((const git_blob *)obj);
      break;
    case GIT_OBJECT_COMMIT:
      show_commit((const git_commit *)obj);
      break;
    case GIT_OBJECT_TREE:
      show_tree((const git_tree *)obj);
      break;
    case GIT_OBJECT_TAG:
      show_tag((const git_tag *)obj);
      break;
    default:
      printf("unknown %s\n", oidstr);
      break;
    }
    break;
  }

  git_object_free(obj);

  return 0;
}

static void usage(const char *message, const char *arg)
{
  if (message && arg)
    fprintf(stderr, "%s: %s\n", message, arg);
  else if (message)
    fprintf(stderr, "%s\n", message);
  fprintf(stderr,
      "usage: cat-file (-t | -s | -e | -p) [-v] [-q] "
      "[-h|--help] [--git-dir=<dir>] <object>\n");
  exit(1);
}

static void parse_opts(struct catfile_options *o, int argc, char *argv[])
{
  struct args_info args = ARGS_INFO_INIT;

  for (args.pos = 1; args.pos < argc; ++args.pos) {
    char *a = argv[args.pos];

    if (a[0] != '-') {
      if (o->rev != NULL)
        usage("Only one rev should be provided", NULL);
      else
        o->rev = a;
    }
    else if (!strcmp(a, "-t"))
      o->action = SHOW_TYPE;
    else if (!strcmp(a, "-s"))
      o->action = SHOW_SIZE;
    else if (!strcmp(a, "-e"))
      o->action = SHOW_NONE;
    else if (!strcmp(a, "-p"))
      o->action = SHOW_PRETTY;
    else if (!strcmp(a, "-q"))
      o->verbose = 0;
    else if (!strcmp(a, "-v"))
      o->verbose = 1;
    else if (!strcmp(a, "--help") || !strcmp(a, "-h"))
      usage(NULL, NULL);
    else if (!match_str_arg(&o->dir, &args, "--git-dir"))
      usage("Unknown option", a);
  }

  if (!o->action || !o->rev)
    usage(NULL, NULL);

}