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