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_cache(flags) ? 1 : 0;
 112         if (write_cache(fd, active_cache, active_nr) ||
 113                         commit_locked_index(index_lock))
 114                 return error ("Could not refresh index");
 115         return result;
 116 }
 117
 118 static void update_index_from_diff(struct diff_queue_struct *q,
 119                 struct diff_options *opt, void *data)
 120 {
 121         int i;
 122         int *discard_flag = data;
 123
 124         /* do_diff_cache() mangled the index */
 125         discard_cache();
 126         *discard_flag = 1;
 127         read_cache();
 128
 129         for (i = 0; i < q->nr; i++) {
 130                 struct diff_filespec *one = q->queue[i]->one;
 131                 if (one->mode) {
 132                         struct cache_entry *ce;
 133                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 134                                 0, 0);
 135                         if (!ce)
 136                                 die("make_cache_entry failed for path '%s'",
 137                                     one->path);
 138                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 139                                 ADD_CACHE_OK_TO_REPLACE);
 140                 } else
 141                         remove_file_from_cache(one->path);
 142         }
 143 }
 144
 145 static int read_from_tree(const char *prefix, const char **argv,
 146                 unsigned char *tree_sha1, int refresh_flags)
 147 {
 148         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 149         int index_fd, index_was_discarded = 0;
 150         struct diff_options opt;
 151
 152         memset(&opt, 0, sizeof(opt));
 153         diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 154         opt.output_format = DIFF_FORMAT_CALLBACK;
 155         opt.format_callback = update_index_from_diff;
 156         opt.format_callback_data = &index_was_discarded;
 157
 158         index_fd = hold_locked_index(lock, 1);
 159         index_was_discarded = 0;
 160         read_cache();
 161         if (do_diff_cache(tree_sha1, &opt))
 162                 return 1;
 163         diffcore_std(&opt);
 164         diff_flush(&opt);
 165         diff_tree_release_paths(&opt);
 166
 167         if (!index_was_discarded)
 168                 /* The index is still clobbered from do_diff_cache() */
 169                 discard_cache();
 170         return update_index_refresh(index_fd, lock, refresh_flags);
 171 }
 172
 173 static void prepend_reflog_action(const char *action, char *buf, size_t size)
 174 {
 175         const char *sep = ": ";
 176         const char *rla = getenv("GIT_REFLOG_ACTION");
 177         if (!rla)
 178                 rla = sep = "";
 179         if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
 180                 warning("Reflog action message too long: %.*s...", 50, buf);
 181 }
 182
 183 int cmd_reset(int argc, const char **argv, const char *prefix)
 184 {
 185         int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
 186         const char *rev = "HEAD";
 187         unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 188                                 *old_orig = NULL, sha1_old_orig[20];
 189         struct commit *commit;
 190         char *reflog_action, msg[1024];
 191         const struct option options[] = {
 192                 OPT_SET_INT(0, "mixed", &reset_type,
 193                                                 "reset HEAD and index", MIXED),
 194                 OPT_SET_INT(0, "soft", &reset_type, "reset only HEAD", SOFT),
 195                 OPT_SET_INT(0, "hard", &reset_type,
 196                                 "reset HEAD, index and working tree", HARD),
 197                 OPT_SET_INT(0, "merge", &reset_type,
 198                                 "reset HEAD, index and working tree", MERGE),
 199                 OPT_BOOLEAN('q', NULL, &quiet,
 200                                 "disable showing new HEAD in hard reset and progress message"),
 201                 OPT_END()
 202         };
 203
 204         git_config(git_default_config, NULL);
 205
 206         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 207                                                 PARSE_OPT_KEEP_DASHDASH);
 208         reflog_action = args_to_str(argv);
 209         setenv("GIT_REFLOG_ACTION", reflog_action, 0);
 210
 211         /*
 212          * Possible arguments are:
 213          *
 214          * git reset [-opts] <rev> <paths>...
 215          * git reset [-opts] <rev> -- <paths>...
 216          * git reset [-opts] -- <paths>...
 217          * git reset [-opts] <paths>...
 218          *
 219          * At this point, argv[i] points immediately after [-opts].
 220          */
 221
 222         if (i < argc) {
 223                 if (!strcmp(argv[i], "--")) {
 224                         i++; /* reset to HEAD, possibly with paths */
 225                 } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
 226                         rev = argv[i];
 227                         i += 2;
 228                 }
 229                 /*
 230                  * Otherwise, argv[i] could be either <rev> or <paths> and
 231                  * has to be unambiguous.
 232                  */
 233                 else if (!get_sha1(argv[i], sha1)) {
 234                         /*
 235                          * Ok, argv[i] looks like a rev; it should not
 236                          * be a filename.
 237                          */
 238                         verify_non_filename(prefix, argv[i]);
 239                         rev = argv[i++];
 240                 } else {
 241                         /* Otherwise we treat this as a filename */
 242                         verify_filename(prefix, argv[i]);
 243                 }
 244         }
 245
 246         if (get_sha1(rev, sha1))
 247                 die("Failed to resolve '%s' as a valid ref.", rev);
 248
 249         commit = lookup_commit_reference(sha1);
 250         if (!commit)
 251                 die("Could not parse object '%s'.", rev);
 252         hashcpy(sha1, commit->object.sha1);
 253
 254         /* git reset tree [--] paths... can be used to
 255          * load chosen paths from the tree into the index without
 256          * affecting the working tree nor HEAD. */
 257         if (i < argc) {
 258                 if (reset_type == MIXED)
 259                         warning("--mixed option is deprecated with paths.");
 260                 else if (reset_type != NONE)
 261                         die("Cannot do %s reset with paths.",
 262                                         reset_type_names[reset_type]);
 263                 return read_from_tree(prefix, argv + i, sha1,
 264                                 quiet ? REFRESH_QUIET : REFRESH_SAY_CHANGED);
 265         }
 266         if (reset_type == NONE)
 267                 reset_type = MIXED; /* by default */
 268
 269         if (reset_type == HARD && is_bare_repository())
 270                 die("hard reset makes no sense in a bare repository");
 271
 272         /* Soft reset does not touch the index file nor the working tree
 273          * at all, but requires them in a good order.  Other resets reset
 274          * the index file to the tree object we are switching to. */
 275         if (reset_type == SOFT) {
 276                 if (is_merge() || read_cache() < 0 || unmerged_cache())
 277                         die("Cannot do a soft reset in the middle of a merge.");
 278         }
 279         else if (reset_index_file(sha1, reset_type, quiet))
 280                 die("Could not reset index file to revision '%s'.", rev);
 281
 282         /* Any resets update HEAD to the head being switched to,
 283          * saving the previous head in ORIG_HEAD before. */
 284         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 285                 old_orig = sha1_old_orig;
 286         if (!get_sha1("HEAD", sha1_orig)) {
 287                 orig = sha1_orig;
 288                 prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
 289                 update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 290         }
 291         else if (old_orig)
 292                 delete_ref("ORIG_HEAD", old_orig, 0);
 293         prepend_reflog_action("updating HEAD", msg, sizeof(msg));
 294         update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 295
 296         switch (reset_type) {
 297         case HARD:
 298                 if (!update_ref_status && !quiet)
 299                         print_new_head_line(commit);
 300                 break;
 301         case SOFT: /* Nothing else to do. */
 302                 break;
 303         case MIXED: /* Report what has not been updated. */
 304                 update_index_refresh(0, NULL,
 305                                 quiet ? REFRESH_QUIET : REFRESH_SAY_CHANGED);
 306                 break;
 307         }
 308
 309         remove_branch_state();
 310
 311         free(reflog_action);
 312
 313         return update_ref_status;
 314 }