builtin-reset.c

   1 /*
   2  * "git reset" builtin command
   3  *
   4  * Copyright (c) 2007 Carlos Rica
   5  *
   6  * Based on git-reset.sh, which is
   7  *
   8  * Copyright (c) 2005, 2006 Linus Torvalds and Junio C Hamano
   9  */
  10 #include "cache.h"
  11 #include "tag.h"
  12 #include "object.h"
  13 #include "commit.h"
  14 #include "run-command.h"
  15 #include "refs.h"
  16 #include "diff.h"
  17 #include "diffcore.h"
  18 #include "tree.h"
  19 #include "branch.h"
  20 #include "parse-options.h"
  21 #include "unpack-trees.h"
  22 #include "cache-tree.h"
  23
  24 static const char * const git_reset_usage[] = {
  25         "git reset [--mixed | --soft | --hard | --merge] [-q] [<commit>]",
  26         "git reset [--mixed] <commit> [--] <paths>...",
  27         NULL
  28 };
  29
  30 enum reset_type { MIXED, SOFT, HARD, MERGE, NONE };
  31 static const char *reset_type_names[] = { "mixed", "soft", "hard", "merge", NULL };
  32
  33 static char *args_to_str(const char **argv)
  34 {
  35         char *buf = NULL;
  36         unsigned long len, space = 0, nr = 0;
  37
  38         for (; *argv; argv++) {
  39                 len = strlen(*argv);
  40                 ALLOC_GROW(buf, nr + 1 + len, space);
  41                 if (nr)
  42                         buf[nr++] = ' ';
  43                 memcpy(buf + nr, *argv, len);
  44                 nr += len;
  45         }
  46         ALLOC_GROW(buf, nr + 1, space);
  47         buf[nr] = '\0';
  48
  49         return buf;
  50 }
  51
  52 static inline int is_merge(void)
  53 {
  54         return !access(git_path("MERGE_HEAD"), F_OK);
  55 }
  56
  57 static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet)
  58 {
  59         int nr = 1;
  60         int newfd;
  61         struct tree_desc desc[2];
  62         struct unpack_trees_options opts;
  63         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
  64
  65         memset(&opts, 0, sizeof(opts));
  66         opts.head_idx = 1;
  67         opts.src_index = &the_index;
  68         opts.dst_index = &the_index;
  69         opts.fn = oneway_merge;
  70         opts.merge = 1;
  71         if (!quiet)
  72                 opts.verbose_update = 1;
  73         switch (reset_type) {
  74         case MERGE:
  75                 opts.update = 1;
  76                 break;
  77         case HARD:
  78                 opts.update = 1;
  79                 /* fallthrough */
  80         default:
  81                 opts.reset = 1;
  82         }
  83
  84         newfd = hold_locked_index(lock, 1);
  85
  86         read_cache_unmerged();
  87
  88         if (!fill_tree_descriptor(desc + nr - 1, sha1))
  89                 return error("Failed to find tree of %s.", sha1_to_hex(sha1));
  90         if (unpack_trees(nr, desc, &opts))
  91                 return -1;
  92         if (write_cache(newfd, active_cache, active_nr) ||
  93             commit_locked_index(lock))
  94                 return error("Could not write new index file.");
  95
  96         return 0;
  97 }
  98
  99 static void print_new_head_line(struct commit *commit)
 100 {
 101         const char *hex, *body;
 102
 103         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 104         printf("HEAD is now at %s", hex);
 105         body = strstr(commit->buffer, "\n\n");
 106         if (body) {
 107                 const char *eol;
 108                 size_t len;
 109                 body += 2;
 110                 eol = strchr(body, '\n');
 111                 len = eol ? eol - body : strlen(body);
 112                 printf(" %.*s\n", (int) len, body);
 113         }
 114         else
 115                 printf("\n");
 116 }
 117
 118 static int update_index_refresh(int fd, struct lock_file *index_lock, int flags)
 119 {
 120         int result;
 121
 122         if (!index_lock) {
 123                 index_lock = xcalloc(1, sizeof(struct lock_file));
 124                 fd = hold_locked_index(index_lock, 1);
 125         }
 126
 127         if (read_cache() < 0)
 128                 return error("Could not read index");
 129
 130         result = refresh_index(&the_index, (flags), NULL, NULL,
 131                                "Unstaged changes after reset:") ? 1 : 0;
 132         if (write_cache(fd, active_cache, active_nr) ||
 133                         commit_locked_index(index_lock))
 134                 return error ("Could not refresh index");
 135         return result;
 136 }
 137
 138 static void update_index_from_diff(struct diff_queue_struct *q,
 139                 struct diff_options *opt, void *data)
 140 {
 141         int i;
 142         int *discard_flag = data;
 143
 144         /* do_diff_cache() mangled the index */
 145         discard_cache();
 146         *discard_flag = 1;
 147         read_cache();
 148
 149         for (i = 0; i < q->nr; i++) {
 150                 struct diff_filespec *one = q->queue[i]->one;
 151                 if (one->mode) {
 152                         struct cache_entry *ce;
 153                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 154                                 0, 0);
 155                         if (!ce)
 156                                 die("make_cache_entry failed for path '%s'",
 157                                     one->path);
 158                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 159                                 ADD_CACHE_OK_TO_REPLACE);
 160                 } else
 161                         remove_file_from_cache(one->path);
 162         }
 163 }
 164
 165 static int interactive_reset(const char *revision, const char **argv,
 166                              const char *prefix)
 167 {
 168         const char **pathspec = NULL;
 169
 170         if (*argv)
 171                 pathspec = get_pathspec(prefix, argv);
 172
 173         return run_add_interactive(revision, "--patch=reset", pathspec);
 174 }
 175
 176 static int read_from_tree(const char *prefix, const char **argv,
 177                 unsigned char *tree_sha1, int refresh_flags)
 178 {
 179         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 180         int index_fd, index_was_discarded = 0;
 181         struct diff_options opt;
 182
 183         memset(&opt, 0, sizeof(opt));
 184         diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 185         opt.output_format = DIFF_FORMAT_CALLBACK;
 186         opt.format_callback = update_index_from_diff;
 187         opt.format_callback_data = &index_was_discarded;
 188
 189         index_fd = hold_locked_index(lock, 1);
 190         index_was_discarded = 0;
 191         read_cache();
 192         if (do_diff_cache(tree_sha1, &opt))
 193                 return 1;
 194         diffcore_std(&opt);
 195         diff_flush(&opt);
 196         diff_tree_release_paths(&opt);
 197
 198         if (!index_was_discarded)
 199                 /* The index is still clobbered from do_diff_cache() */
 200                 discard_cache();
 201         return update_index_refresh(index_fd, lock, refresh_flags);
 202 }
 203
 204 static void prepend_reflog_action(const char *action, char *buf, size_t size)
 205 {
 206         const char *sep = ": ";
 207         const char *rla = getenv("GIT_REFLOG_ACTION");
 208         if (!rla)
 209                 rla = sep = "";
 210         if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
 211                 warning("Reflog action message too long: %.*s...", 50, buf);
 212 }
 213
 214 int cmd_reset(int argc, const char **argv, const char *prefix)
 215 {
 216         int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
 217         int patch_mode = 0;
 218         const char *rev = "HEAD";
 219         unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 220                                 *old_orig = NULL, sha1_old_orig[20];
 221         struct commit *commit;
 222         char *reflog_action, msg[1024];
 223         const struct option options[] = {
 224                 OPT__QUIET(&quiet),
 225                 OPT_SET_INT(0, "mixed", &reset_type,
 226                                                 "reset HEAD and index", MIXED),
 227                 OPT_SET_INT(0, "soft", &reset_type, "reset only HEAD", SOFT),
 228                 OPT_SET_INT(0, "hard", &reset_type,
 229                                 "reset HEAD, index and working tree", HARD),
 230                 OPT_SET_INT(0, "merge", &reset_type,
 231                                 "reset HEAD, index and working tree", MERGE),
 232                 OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
 233                 OPT_END()
 234         };
 235
 236         git_config(git_default_config, NULL);
 237
 238         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 239                                                 PARSE_OPT_KEEP_DASHDASH);
 240         reflog_action = args_to_str(argv);
 241         setenv("GIT_REFLOG_ACTION", reflog_action, 0);
 242
 243         /*
 244          * Possible arguments are:
 245          *
 246          * git reset [-opts] <rev> <paths>...
 247          * git reset [-opts] <rev> -- <paths>...
 248          * git reset [-opts] -- <paths>...
 249          * git reset [-opts] <paths>...
 250          *
 251          * At this point, argv[i] points immediately after [-opts].
 252          */
 253
 254         if (i < argc) {
 255                 if (!strcmp(argv[i], "--")) {
 256                         i++; /* reset to HEAD, possibly with paths */
 257                 } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
 258                         rev = argv[i];
 259                         i += 2;
 260                 }
 261                 /*
 262                  * Otherwise, argv[i] could be either <rev> or <paths> and
 263                  * has to be unambiguous.
 264                  */
 265                 else if (!get_sha1(argv[i], sha1)) {
 266                         /*
 267                          * Ok, argv[i] looks like a rev; it should not
 268                          * be a filename.
 269                          */
 270                         verify_non_filename(prefix, argv[i]);
 271                         rev = argv[i++];
 272                 } else {
 273                         /* Otherwise we treat this as a filename */
 274                         verify_filename(prefix, argv[i]);
 275                 }
 276         }
 277
 278         if (get_sha1(rev, sha1))
 279                 die("Failed to resolve '%s' as a valid ref.", rev);
 280
 281         commit = lookup_commit_reference(sha1);
 282         if (!commit)
 283                 die("Could not parse object '%s'.", rev);
 284         hashcpy(sha1, commit->object.sha1);
 285
 286         if (patch_mode) {
 287                 if (reset_type != NONE)
 288                         die("--patch is incompatible with --{hard,mixed,soft}");
 289                 return interactive_reset(rev, argv + i, prefix);
 290         }
 291
 292         /* git reset tree [--] paths... can be used to
 293          * load chosen paths from the tree into the index without
 294          * affecting the working tree nor HEAD. */
 295         if (i < argc) {
 296                 if (reset_type == MIXED)
 297                         warning("--mixed option is deprecated with paths.");
 298                 else if (reset_type != NONE)
 299                         die("Cannot do %s reset with paths.",
 300                                         reset_type_names[reset_type]);
 301                 return read_from_tree(prefix, argv + i, sha1,
 302                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 303         }
 304         if (reset_type == NONE)
 305                 reset_type = MIXED; /* by default */
 306
 307         if (reset_type == HARD || reset_type == MERGE)
 308                 setup_work_tree();
 309
 310         if (reset_type == MIXED && is_bare_repository())
 311                 die("%s reset is not allowed in a bare repository",
 312                     reset_type_names[reset_type]);
 313
 314         /* Soft reset does not touch the index file nor the working tree
 315          * at all, but requires them in a good order.  Other resets reset
 316          * the index file to the tree object we are switching to. */
 317         if (reset_type == SOFT) {
 318                 if (is_merge() || read_cache() < 0 || unmerged_cache())
 319                         die("Cannot do a soft reset in the middle of a merge.");
 320         }
 321         else if (reset_index_file(sha1, reset_type, quiet))
 322                 die("Could not reset index file to revision '%s'.", rev);
 323
 324         /* Any resets update HEAD to the head being switched to,
 325          * saving the previous head in ORIG_HEAD before. */
 326         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 327                 old_orig = sha1_old_orig;
 328         if (!get_sha1("HEAD", sha1_orig)) {
 329                 orig = sha1_orig;
 330                 prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
 331                 update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 332         }
 333         else if (old_orig)
 334                 delete_ref("ORIG_HEAD", old_orig, 0);
 335         prepend_reflog_action("updating HEAD", msg, sizeof(msg));
 336         update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 337
 338         switch (reset_type) {
 339         case HARD:
 340                 if (!update_ref_status && !quiet)
 341                         print_new_head_line(commit);
 342                 break;
 343         case SOFT: /* Nothing else to do. */
 344                 break;
 345         case MIXED: /* Report what has not been updated. */
 346                 update_index_refresh(0, NULL,
 347                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 348                 break;
 349         }
 350
 351         remove_branch_state();
 352
 353         free(reflog_action);
 354
 355         return update_ref_status;
 356 }