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