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]  [<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         char b;
  50         ssize_t len;
  51         struct child_process cmd;
  52         const char *argv_ls_files[] = {"ls-files", "--unmerged", NULL};
  53
  54         memset(&cmd, 0, sizeof(cmd));
  55         cmd.argv = argv_ls_files;
  56         cmd.git_cmd = 1;
  57         cmd.out = -1;
  58
  59         if (start_command(&cmd))
  60                 die("Could not run sub-command: git ls-files");
  61
  62         len = xread(cmd.out, &b, 1);
  63         if (len < 0)
  64                 die("Could not read output from git ls-files: %s",
  65                                                 strerror(errno));
  66         finish_command(&cmd);
  67
  68         return len;
  69 }
  70
  71 static int reset_index_file(const unsigned char *sha1, int is_hard_reset)
  72 {
  73         int i = 0;
  74         const char *args[6];
  75
  76         args[i++] = "read-tree";
  77         args[i++] = "-v";
  78         args[i++] = "--reset";
  79         if (is_hard_reset)
  80                 args[i++] = "-u";
  81         args[i++] = sha1_to_hex(sha1);
  82         args[i] = NULL;
  83
  84         return run_command_v_opt(args, RUN_GIT_CMD);
  85 }
  86
  87 static void print_new_head_line(struct commit *commit)
  88 {
  89         const char *hex, *dots = "...", *body;
  90
  91         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
  92         if (!hex) {
  93                 hex = sha1_to_hex(commit->object.sha1);
  94                 dots = "";
  95         }
  96         printf("HEAD is now at %s%s", hex, dots);
  97         body = strstr(commit->buffer, "\n\n");
  98         if (body) {
  99                 const char *eol;
 100                 size_t len;
 101                 body += 2;
 102                 eol = strchr(body, '\n');
 103                 len = eol ? eol - body : strlen(body);
 104                 printf(" %.*s\n", (int) len, body);
 105         }
 106         else
 107                 printf("\n");
 108 }
 109
 110 static int update_index_refresh(void)
 111 {
 112         const char *argv_update_index[] = {"update-index", "--refresh", NULL};
 113         return run_command_v_opt(argv_update_index, RUN_GIT_CMD);
 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
 121         /* do_diff_cache() mangled the index */
 122         discard_cache();
 123         read_cache();
 124
 125         for (i = 0; i < q->nr; i++) {
 126                 struct diff_filespec *one = q->queue[i]->one;
 127                 if (one->mode) {
 128                         struct cache_entry *ce;
 129                         ce = make_cache_entry(one->mode, one->sha1, one->path,
 130                                 0, 0);
 131                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 132                                 ADD_CACHE_OK_TO_REPLACE);
 133                 } else
 134                         remove_file_from_cache(one->path);
 135         }
 136 }
 137
 138 static int read_from_tree(const char *prefix, const char **argv,
 139                 unsigned char *tree_sha1)
 140 {
 141         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 142         int index_fd;
 143         struct diff_options opt;
 144
 145         memset(&opt, 0, sizeof(opt));
 146         diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 147         opt.output_format = DIFF_FORMAT_CALLBACK;
 148         opt.format_callback = update_index_from_diff;
 149
 150         index_fd = hold_locked_index(lock, 1);
 151         read_cache();
 152         if (do_diff_cache(tree_sha1, &opt))
 153                 return 1;
 154         diffcore_std(&opt);
 155         diff_flush(&opt);
 156         return write_cache(index_fd, active_cache, active_nr) ||
 157                 close(index_fd) ||
 158                 commit_locked_index(lock);
 159 }
 160
 161 static void prepend_reflog_action(const char *action, char *buf, size_t size)
 162 {
 163         const char *sep = ": ";
 164         const char *rla = getenv("GIT_REFLOG_ACTION");
 165         if (!rla)
 166                 rla = sep = "";
 167         if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
 168                 warning("Reflog action message too long: %.*s...", 50, buf);
 169 }
 170
 171 enum reset_type { MIXED, SOFT, HARD, NONE };
 172 static char *reset_type_names[] = { "mixed", "soft", "hard", NULL };
 173
 174 int cmd_reset(int argc, const char **argv, const char *prefix)
 175 {
 176         int i = 1, reset_type = NONE, update_ref_status = 0;
 177         const char *rev = "HEAD";
 178         unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 179                                 *old_orig = NULL, sha1_old_orig[20];
 180         struct commit *commit;
 181         char *reflog_action, msg[1024];
 182
 183         git_config(git_default_config);
 184
 185         reflog_action = args_to_str(argv);
 186         setenv("GIT_REFLOG_ACTION", reflog_action, 0);
 187
 188         if (i < argc) {
 189                 if (!strcmp(argv[i], "--mixed")) {
 190                         reset_type = MIXED;
 191                         i++;
 192                 }
 193                 else if (!strcmp(argv[i], "--soft")) {
 194                         reset_type = SOFT;
 195                         i++;
 196                 }
 197                 else if (!strcmp(argv[i], "--hard")) {
 198                         reset_type = HARD;
 199                         i++;
 200                 }
 201         }
 202
 203         if (i < argc && argv[i][0] != '-')
 204                 rev = argv[i++];
 205
 206         if (get_sha1(rev, sha1))
 207                 die("Failed to resolve '%s' as a valid ref.", rev);
 208
 209         commit = lookup_commit_reference(sha1);
 210         if (!commit)
 211                 die("Could not parse object '%s'.", rev);
 212         hashcpy(sha1, commit->object.sha1);
 213
 214         if (i < argc && !strcmp(argv[i], "--"))
 215                 i++;
 216         else if (i < argc && argv[i][0] == '-')
 217                 usage(builtin_reset_usage);
 218
 219         /* git reset tree [--] paths... can be used to
 220          * load chosen paths from the tree into the index without
 221          * affecting the working tree nor HEAD. */
 222         if (i < argc) {
 223                 if (reset_type == MIXED)
 224                         warning("--mixed option is deprecated with paths.");
 225                 else if (reset_type != NONE)
 226                         die("Cannot do %s reset with paths.",
 227                                         reset_type_names[reset_type]);
 228                 if (read_from_tree(prefix, argv + i, sha1))
 229                         return 1;
 230                 return update_index_refresh() ? 1 : 0;
 231         }
 232         if (reset_type == NONE)
 233                 reset_type = MIXED; /* by default */
 234
 235         /* Soft reset does not touch the index file nor the working tree
 236          * at all, but requires them in a good order.  Other resets reset
 237          * the index file to the tree object we are switching to. */
 238         if (reset_type == SOFT) {
 239                 if (is_merge() || unmerged_files())
 240                         die("Cannot do a soft reset in the middle of a merge.");
 241         }
 242         else if (reset_index_file(sha1, (reset_type == HARD)))
 243                 die("Could not reset index file to revision '%s'.", rev);
 244
 245         /* Any resets update HEAD to the head being switched to,
 246          * saving the previous head in ORIG_HEAD before. */
 247         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 248                 old_orig = sha1_old_orig;
 249         if (!get_sha1("HEAD", sha1_orig)) {
 250                 orig = sha1_orig;
 251                 prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
 252                 update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 253         }
 254         else if (old_orig)
 255                 delete_ref("ORIG_HEAD", old_orig);
 256         prepend_reflog_action("updating HEAD", msg, sizeof(msg));
 257         update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 258
 259         switch (reset_type) {
 260         case HARD:
 261                 if (!update_ref_status)
 262                         print_new_head_line(commit);
 263                 break;
 264         case SOFT: /* Nothing else to do. */
 265                 break;
 266         case MIXED: /* Report what has not been updated. */
 267                 update_index_refresh();
 268                 break;
 269         }
 270
 271         unlink(git_path("MERGE_HEAD"));
 272         unlink(git_path("rr-cache/MERGE_RR"));
 273         unlink(git_path("MERGE_MSG"));
 274         unlink(git_path("SQUASH_MSG"));
 275
 276         free(reflog_action);
 277
 278         return update_ref_status;
 279 }