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 interactive_reset(const char *revision, const char **argv,
 147                              const char *prefix)
 148 {
 149         const char **pathspec = NULL;
 150
 151         if (*argv)
 152                 pathspec = get_pathspec(prefix, argv);
 153
 154         return run_add_interactive(revision, "--patch=reset", pathspec);
 155 }
 156
 157 static int read_from_tree(const char *prefix, const char **argv,
 158                 unsigned char *tree_sha1, int refresh_flags)
 159 {
 160         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 161         int index_fd, index_was_discarded = 0;
 162         struct diff_options opt;
 163
 164         memset(&opt, 0, sizeof(opt));
 165         diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 166         opt.output_format = DIFF_FORMAT_CALLBACK;
 167         opt.format_callback = update_index_from_diff;
 168         opt.format_callback_data = &index_was_discarded;
 169
 170         index_fd = hold_locked_index(lock, 1);
 171         index_was_discarded = 0;
 172         read_cache();
 173         if (do_diff_cache(tree_sha1, &opt))
 174                 return 1;
 175         diffcore_std(&opt);
 176         diff_flush(&opt);
 177         diff_tree_release_paths(&opt);
 178
 179         if (!index_was_discarded)
 180                 /* The index is still clobbered from do_diff_cache() */
 181                 discard_cache();
 182         return update_index_refresh(index_fd, lock, refresh_flags);
 183 }
 184
 185 static void prepend_reflog_action(const char *action, char *buf, size_t size)
 186 {
 187         const char *sep = ": ";
 188         const char *rla = getenv("GIT_REFLOG_ACTION");
 189         if (!rla)
 190                 rla = sep = "";
 191         if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
 192                 warning("Reflog action message too long: %.*s...", 50, buf);
 193 }
 194
 195 int cmd_reset(int argc, const char **argv, const char *prefix)
 196 {
 197         int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
 198         int patch_mode = 0;
 199         const char *rev = "HEAD";
 200         unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 201                                 *old_orig = NULL, sha1_old_orig[20];
 202         struct commit *commit;
 203         char *reflog_action, msg[1024];
 204         const struct option options[] = {
 205                 OPT_SET_INT(0, "mixed", &reset_type,
 206                                                 "reset HEAD and index", MIXED),
 207                 OPT_SET_INT(0, "soft", &reset_type, "reset only HEAD", SOFT),
 208                 OPT_SET_INT(0, "hard", &reset_type,
 209                                 "reset HEAD, index and working tree", HARD),
 210                 OPT_SET_INT(0, "merge", &reset_type,
 211                                 "reset HEAD, index and working tree", MERGE),
 212                 OPT_BOOLEAN('q', NULL, &quiet,
 213                                 "disable showing new HEAD in hard reset and progress message"),
 214                 OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
 215                 OPT_END()
 216         };
 217
 218         git_config(git_default_config, NULL);
 219
 220         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 221                                                 PARSE_OPT_KEEP_DASHDASH);
 222         reflog_action = args_to_str(argv);
 223         setenv("GIT_REFLOG_ACTION", reflog_action, 0);
 224
 225         /*
 226          * Possible arguments are:
 227          *
 228          * git reset [-opts] <rev> <paths>...
 229          * git reset [-opts] <rev> -- <paths>...
 230          * git reset [-opts] -- <paths>...
 231          * git reset [-opts] <paths>...
 232          *
 233          * At this point, argv[i] points immediately after [-opts].
 234          */
 235
 236         if (i < argc) {
 237                 if (!strcmp(argv[i], "--")) {
 238                         i++; /* reset to HEAD, possibly with paths */
 239                 } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
 240                         rev = argv[i];
 241                         i += 2;
 242                 }
 243                 /*
 244                  * Otherwise, argv[i] could be either <rev> or <paths> and
 245                  * has to be unambiguous.
 246                  */
 247                 else if (!get_sha1(argv[i], sha1)) {
 248                         /*
 249                          * Ok, argv[i] looks like a rev; it should not
 250                          * be a filename.
 251                          */
 252                         verify_non_filename(prefix, argv[i]);
 253                         rev = argv[i++];
 254                 } else {
 255                         /* Otherwise we treat this as a filename */
 256                         verify_filename(prefix, argv[i]);
 257                 }
 258         }
 259
 260         if (get_sha1(rev, sha1))
 261                 die("Failed to resolve '%s' as a valid ref.", rev);
 262
 263         commit = lookup_commit_reference(sha1);
 264         if (!commit)
 265                 die("Could not parse object '%s'.", rev);
 266         hashcpy(sha1, commit->object.sha1);
 267
 268         if (patch_mode) {
 269                 if (reset_type != NONE)
 270                         die("--patch is incompatible with --{hard,mixed,soft}");
 271                 return interactive_reset(rev, argv + i, prefix);
 272         }
 273
 274         /* git reset tree [--] paths... can be used to
 275          * load chosen paths from the tree into the index without
 276          * affecting the working tree nor HEAD. */
 277         if (i < argc) {
 278                 if (reset_type == MIXED)
 279                         warning("--mixed option is deprecated with paths.");
 280                 else if (reset_type != NONE)
 281                         die("Cannot do %s reset with paths.",
 282                                         reset_type_names[reset_type]);
 283                 return read_from_tree(prefix, argv + i, sha1,
 284                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 285         }
 286         if (reset_type == NONE)
 287                 reset_type = MIXED; /* by default */
 288
 289         if (reset_type == HARD && is_bare_repository())
 290                 die("hard reset makes no sense in a bare repository");
 291
 292         /* Soft reset does not touch the index file nor the working tree
 293          * at all, but requires them in a good order.  Other resets reset
 294          * the index file to the tree object we are switching to. */
 295         if (reset_type == SOFT) {
 296                 if (is_merge() || read_cache() < 0 || unmerged_cache())
 297                         die("Cannot do a soft reset in the middle of a merge.");
 298         }
 299         else if (reset_index_file(sha1, reset_type, quiet))
 300                 die("Could not reset index file to revision '%s'.", rev);
 301
 302         /* Any resets update HEAD to the head being switched to,
 303          * saving the previous head in ORIG_HEAD before. */
 304         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 305                 old_orig = sha1_old_orig;
 306         if (!get_sha1("HEAD", sha1_orig)) {
 307                 orig = sha1_orig;
 308                 prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
 309                 update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 310         }
 311         else if (old_orig)
 312                 delete_ref("ORIG_HEAD", old_orig, 0);
 313         prepend_reflog_action("updating HEAD", msg, sizeof(msg));
 314         update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 315
 316         switch (reset_type) {
 317         case HARD:
 318                 if (!update_ref_status && !quiet)
 319                         print_new_head_line(commit);
 320                 break;
 321         case SOFT: /* Nothing else to do. */
 322                 break;
 323         case MIXED: /* Report what has not been updated. */
 324                 update_index_refresh(0, NULL,
 325                                 quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN);
 326                 break;
 327         }
 328
 329         remove_branch_state();
 330
 331         free(reflog_action);
 332
 333         return update_ref_status;
 334 }