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 [-q] <commit> [--] <paths>...",
  27         "git reset --patch [<commit>] [--] [<paths>...]",
  28         NULL
  29 };
  30
  31 enum reset_type { MIXED, SOFT, HARD, MERGE, NONE };
  32 static const char *reset_type_names[] = { "mixed", "soft", "hard", "merge", NULL };
  33
  34 static char *args_to_str(const char **argv)
  35 {
  36         char *buf = NULL;
  37         unsigned long len, space = 0, nr = 0;
  38
  39         for (; *argv; argv++) {
  40                 len = strlen(*argv);
  41                 ALLOC_GROW(buf, nr + 1 + len, space);
  42                 if (nr)
  43                         buf[nr++] = ' ';
  44                 memcpy(buf + nr, *argv, len);
  45                 nr += len;
  46         }
  47         ALLOC_GROW(buf, nr + 1, space);
  48         buf[nr] = '\0';
  49
  50         return buf;
  51 }
  52
  53 static inline int is_merge(void)
  54 {
  55         return !access(git_path("MERGE_HEAD"), F_OK);
  56 }
  57
  58 static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet)
  59 {
  60         int nr = 1;
  61         int newfd;
  62         struct tree_desc desc[2];
  63         struct unpack_trees_options opts;
  64         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
  65
  66         memset(&opts, 0, sizeof(opts));
  67         opts.head_idx = 1;
  68         opts.src_index = &the_index;
  69         opts.dst_index = &the_index;
  70         opts.fn = oneway_merge;
  71         opts.merge = 1;
  72         if (!quiet)
  73                 opts.verbose_update = 1;
  74         switch (reset_type) {
  75         case MERGE:
  76                 opts.update = 1;
  77                 break;
  78         case HARD:
  79                 opts.update = 1;
  80                 /* fallthrough */
  81         default:
  82                 opts.reset = 1;
  83         }
  84
  85         newfd = hold_locked_index(lock, 1);
  86
  87         read_cache_unmerged();
  88
  89         if (!fill_tree_descriptor(desc + nr - 1, sha1))
  90                 return error("Failed to find tree of %s.", sha1_to_hex(sha1));
  91         if (unpack_trees(nr, desc, &opts))
  92                 return -1;
  93         if (write_cache(newfd, active_cache, active_nr) ||
  94             commit_locked_index(lock))
  95                 return error("Could not write new index file.");
  96
  97         return 0;
  98 }
  99
 100 static void print_new_head_line(struct commit *commit)
 101 {
 102         const char *hex, *body;
 103
 104         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 105         printf("HEAD is now at %s", hex);
 106         body = strstr(commit->buffer, "\n\n");
 107         if (body) {
 108                 const char *eol;
 109                 size_t len;
 110                 body += 2;
 111                 eol = strchr(body, '\n');
 112                 len = eol ? eol - body : strlen(body);
 113                 printf(" %.*s\n", (int) len, body);
 114         }
 115         else
 116                 printf("\n");
 117 }
 118
 119 static int update_index_refresh(int fd, struct lock_file *index_lock, int flags)
 120 {
 121         int result;
 122
 123         if (!index_lock) {
 124                 index_lock = xcalloc(1, sizeof(struct lock_file));
 125                 fd = hold_locked_index(index_lock, 1);
 126         }
 127
 128         if (read_cache() < 0)
 129                 return error("Could not read index");
 130
 131         result = refresh_index(&the_index, (flags), NULL, NULL,
 132                                "Unstaged changes after reset:") ? 1 : 0;
 133         if (write_cache(fd, active_cache, active_nr) ||
 134                         commit_locked_index(index_lock))
 135                 return error ("Could not refresh index");
 136         return result;
 137 }
 138
 139 static void update_index_from_diff(struct diff_queue_struct *q,
 140                 struct diff_options *opt, void *data)
 141 {
 142         int i;
 143         int *discard_flag = data;
 144
 145         /* do_diff_cache() mangled the index */
 146         discard_cache();
 147         *discard_flag = 1;
 148         read_cache();
 149
 150         for (i = 0; i < q->nr; i++) {
 151                 struct diff_filespec *one = q->queue[i]->one;
 152                 if (one->mode) {
 153                         struct cache_entry *ce;
 154                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 155                                 0, 0);
 156                         if (!ce)
 157                                 die("make_cache_entry failed for path '%s'",
 158                                     one->path);
 159                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 160                                 ADD_CACHE_OK_TO_REPLACE);
 161                 } else
 162                         remove_file_from_cache(one->path);
 163         }
 164 }
 165
 166 static int interactive_reset(const char *revision, const char **argv,
 167                              const char *prefix)
 168 {
 169         const char **pathspec = NULL;
 170
 171         if (*argv)
 172                 pathspec = get_pathspec(prefix, argv);
 173
 174         return run_add_interactive(revision, "--patch=reset", pathspec);
 175 }
 176
 177 static int read_from_tree(const char *prefix, const char **argv,
 178                 unsigned char *tree_sha1, int refresh_flags)
 179 {
 180         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 181         int index_fd, index_was_discarded = 0;
 182         struct diff_options opt;
 183
 184         memset(&opt, 0, sizeof(opt));
 185         diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 186         opt.output_format = DIFF_FORMAT_CALLBACK;
 187         opt.format_callback = update_index_from_diff;
 188         opt.format_callback_data = &index_was_discarded;
 189
 190         index_fd = hold_locked_index(lock, 1);
 191         index_was_discarded = 0;
 192         read_cache();
 193         if (do_diff_cache(tree_sha1, &opt))
 194                 return 1;
 195         diffcore_std(&opt);
 196         diff_flush(&opt);
 197         diff_tree_release_paths(&opt);
 198
 199         if (!index_was_discarded)
 200                 /* The index is still clobbered from do_diff_cache() */
 201                 discard_cache();
 202         return update_index_refresh(index_fd, lock, refresh_flags);
 203 }
 204
 205 static void prepend_reflog_action(const char *action, char *buf, size_t size)
 206 {
 207         const char *sep = ": ";
 208         const char *rla = getenv("GIT_REFLOG_ACTION");
 209         if (!rla)
 210                 rla = sep = "";
 211         if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
 212                 warning("Reflog action message too long: %.*s...", 50, buf);
 213 }
 214
 215 int cmd_reset(int argc, const char **argv, const char *prefix)
 216 {
 217         int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
 218         int patch_mode = 0;
 219         const char *rev = "HEAD";
 220         unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 221                                 *old_orig = NULL, sha1_old_orig[20];
 222         struct commit *commit;
 223         char *reflog_action, msg[1024];
 224         const struct option options[] = {
 225                 OPT__QUIET(&quiet),
 226                 OPT_SET_INT(0, "mixed", &reset_type,
 227                                                 "reset HEAD and index", MIXED),
 228                 OPT_SET_INT(0, "soft", &reset_type, "reset only HEAD", SOFT),
 229                 OPT_SET_INT(0, "hard", &reset_type,
 230                                 "reset HEAD, index and working tree", HARD),
 231                 OPT_SET_INT(0, "merge", &reset_type,
 232                                 "reset HEAD, index and working tree", MERGE),
 233                 OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
 234                 OPT_END()
 235         };
 236
 237         git_config(git_default_config, NULL);
 238
 239         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 240                                                 PARSE_OPT_KEEP_DASHDASH);
 241         reflog_action = args_to_str(argv);
 242         setenv("GIT_REFLOG_ACTION", reflog_action, 0);
 243
 244         /*
 245          * Possible arguments are:
 246          *
 247          * git reset [-opts] <rev> <paths>...
 248          * git reset [-opts] <rev> -- <paths>...
 249          * git reset [-opts] -- <paths>...
 250          * git reset [-opts] <paths>...
 251          *
 252          * At this point, argv[i] points immediately after [-opts].
 253          */
 254
 255         if (i < argc) {
 256                 if (!strcmp(argv[i], "--")) {
 257                         i++; /* reset to HEAD, possibly with paths */
 258                 } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
 259                         rev = argv[i];
 260                         i += 2;
 261                 }
 262                 /*
 263                  * Otherwise, argv[i] could be either <rev> or <paths> and
 264                  * has to be unambiguous.
 265                  */
 266                 else if (!get_sha1(argv[i], sha1)) {
 267                         /*
 268                          * Ok, argv[i] looks like a rev; it should not
 269                          * be a filename.
 270                          */
 271                         verify_non_filename(prefix, argv[i]);
 272                         rev = argv[i++];
 273                 } else {
 274                         /* Otherwise we treat this as a filename */
 275                         verify_filename(prefix, argv[i]);
 276                 }
 277         }
 278
 279         if (get_sha1(rev, sha1))
 280                 die("Failed to resolve '%s' as a valid ref.", rev);
 281
 282         commit = lookup_commit_reference(sha1);
 283         if (!commit)
 284                 die("Could not parse object '%s'.", rev);
 285         hashcpy(sha1, commit->object.sha1);
 286
 287         if (patch_mode) {
 288                 if (reset_type != NONE)
 289                         die("--patch is incompatible with --{hard,mixed,soft}");
 290                 return interactive_reset(rev, argv + i, prefix);
 291         }
 292
 293         /* git reset tree [--] paths... can be used to
 294          * load chosen paths from the tree into the index without
 295          * affecting the working tree nor HEAD. */
 296         if (i < argc) {
 297                 if (reset_type == MIXED)
 298                         warning("--mixed option is deprecated with paths.");
 299                 else if (reset_type != NONE)
 300                         die("Cannot do %s reset with paths.",
 301                                         reset_type_names[reset_type]);
 302                 return read_from_tree(prefix, argv + i, sha1,
 303                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 304         }
 305         if (reset_type == NONE)
 306                 reset_type = MIXED; /* by default */
 307
 308         if (reset_type == HARD || reset_type == MERGE)
 309                 setup_work_tree();
 310
 311         if (reset_type == MIXED && is_bare_repository())
 312                 die("%s reset is not allowed in a bare repository",
 313                     reset_type_names[reset_type]);
 314
 315         /* Soft reset does not touch the index file nor the working tree
 316          * at all, but requires them in a good order.  Other resets reset
 317          * the index file to the tree object we are switching to. */
 318         if (reset_type == SOFT) {
 319                 if (is_merge() || read_cache() < 0 || unmerged_cache())
 320                         die("Cannot do a soft reset in the middle of a merge.");
 321         }
 322         else if (reset_index_file(sha1, reset_type, quiet))
 323                 die("Could not reset index file to revision '%s'.", rev);
 324
 325         /* Any resets update HEAD to the head being switched to,
 326          * saving the previous head in ORIG_HEAD before. */
 327         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 328                 old_orig = sha1_old_orig;
 329         if (!get_sha1("HEAD", sha1_orig)) {
 330                 orig = sha1_orig;
 331                 prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
 332                 update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 333         }
 334         else if (old_orig)
 335                 delete_ref("ORIG_HEAD", old_orig, 0);
 336         prepend_reflog_action("updating HEAD", msg, sizeof(msg));
 337         update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 338
 339         switch (reset_type) {
 340         case HARD:
 341                 if (!update_ref_status && !quiet)
 342                         print_new_head_line(commit);
 343                 break;
 344         case SOFT: /* Nothing else to do. */
 345                 break;
 346         case MIXED: /* Report what has not been updated. */
 347                 update_index_refresh(0, NULL,
 348                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 349                 break;
 350         }
 351
 352         remove_branch_state();
 353
 354         free(reflog_action);
 355
 356         return update_ref_status;
 357 }