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