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