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