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