Andrew's git - gitweb.git/blob

   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
  22static const char * const git_reset_usage[] = {
  23        "git reset [--mixed | --soft | --hard] [-q] [<commit>]",
  24        "git reset [--mixed] <commit> [--] <paths>...",
  25        NULL
  26};
  27
  28static 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
  47static inline int is_merge(void)
  48{
  49        return !access(git_path("MERGE_HEAD"), F_OK);
  50}
  51
  52static 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
  69static 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
  88static int update_index_refresh(int fd, struct lock_file *index_lock, int flags)
  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
 100        result = refresh_cache(flags) ? 1 : 0;
 101        if (write_cache(fd, active_cache, active_nr) ||
 102                        commit_locked_index(index_lock))
 103                return error ("Could not refresh index");
 104        return result;
 105}
 106
 107static void update_index_from_diff(struct diff_queue_struct *q,
 108                struct diff_options *opt, void *data)
 109{
 110        int i;
 111        int *discard_flag = data;
 112
 113        /* do_diff_cache() mangled the index */
 114        discard_cache();
 115        *discard_flag = 1;
 116        read_cache();
 117
 118        for (i = 0; i < q->nr; i++) {
 119                struct diff_filespec *one = q->queue[i]->one;
 120                if (one->mode) {
 121                        struct cache_entry *ce;
 122                        ce = make_cache_entry(one->mode, one->sha1, one->path,
 123                                0, 0);
 124                        if (!ce)
 125                                die("make_cache_entry failed for path '%s'",
 126                                    one->path);
 127                        add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 128                                ADD_CACHE_OK_TO_REPLACE);
 129                } else
 130                        remove_file_from_cache(one->path);
 131        }
 132}
 133
 134static int read_from_tree(const char *prefix, const char **argv,
 135                unsigned char *tree_sha1, int refresh_flags)
 136{
 137        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 138        int index_fd, index_was_discarded = 0;
 139        struct diff_options opt;
 140
 141        memset(&opt, 0, sizeof(opt));
 142        diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
 143        opt.output_format = DIFF_FORMAT_CALLBACK;
 144        opt.format_callback = update_index_from_diff;
 145        opt.format_callback_data = &index_was_discarded;
 146
 147        index_fd = hold_locked_index(lock, 1);
 148        index_was_discarded = 0;
 149        read_cache();
 150        if (do_diff_cache(tree_sha1, &opt))
 151                return 1;
 152        diffcore_std(&opt);
 153        diff_flush(&opt);
 154        diff_tree_release_paths(&opt);
 155
 156        if (!index_was_discarded)
 157                /* The index is still clobbered from do_diff_cache() */
 158                discard_cache();
 159        return update_index_refresh(index_fd, lock, refresh_flags);
 160}
 161
 162static void prepend_reflog_action(const char *action, char *buf, size_t size)
 163{
 164        const char *sep = ": ";
 165        const char *rla = getenv("GIT_REFLOG_ACTION");
 166        if (!rla)
 167                rla = sep = "";
 168        if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
 169                warning("Reflog action message too long: %.*s...", 50, buf);
 170}
 171
 172enum reset_type { MIXED, SOFT, HARD, NONE };
 173static const char *reset_type_names[] = { "mixed", "soft", "hard", NULL };
 174
 175int cmd_reset(int argc, const char **argv, const char *prefix)
 176{
 177        int i = 0, reset_type = NONE, update_ref_status = 0, quiet = 0;
 178        const char *rev = "HEAD";
 179        unsigned char sha1[20], *orig = NULL, sha1_orig[20],
 180                                *old_orig = NULL, sha1_old_orig[20];
 181        struct commit *commit;
 182        char *reflog_action, msg[1024];
 183        const struct option options[] = {
 184                OPT_SET_INT(0, "mixed", &reset_type,
 185                                                "reset HEAD and index", MIXED),
 186                OPT_SET_INT(0, "soft", &reset_type, "reset only HEAD", SOFT),
 187                OPT_SET_INT(0, "hard", &reset_type,
 188                                "reset HEAD, index and working tree", HARD),
 189                OPT_BOOLEAN('q', NULL, &quiet,
 190                                "disable showing new HEAD in hard reset and progress message"),
 191                OPT_END()
 192        };
 193
 194        git_config(git_default_config, NULL);
 195
 196        argc = parse_options(argc, argv, options, git_reset_usage,
 197                                                PARSE_OPT_KEEP_DASHDASH);
 198        reflog_action = args_to_str(argv);
 199        setenv("GIT_REFLOG_ACTION", reflog_action, 0);
 200
 201        /*
 202         * Possible arguments are:
 203         *
 204         * git reset [-opts] <rev> <paths>...
 205         * git reset [-opts] <rev> -- <paths>...
 206         * git reset [-opts] -- <paths>...
 207         * git reset [-opts] <paths>...
 208         *
 209         * At this point, argv[i] points immediately after [-opts].
 210         */
 211
 212        if (i < argc) {
 213                if (!strcmp(argv[i], "--")) {
 214                        i++; /* reset to HEAD, possibly with paths */
 215                } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
 216                        rev = argv[i];
 217                        i += 2;
 218                }
 219                /*
 220                 * Otherwise, argv[i] could be either <rev> or <paths> and
 221                 * has to be unambigous.
 222                 */
 223                else if (!get_sha1(argv[i], sha1)) {
 224                        /*
 225                         * Ok, argv[i] looks like a rev; it should not
 226                         * be a filename.
 227                         */
 228                        verify_non_filename(prefix, argv[i]);
 229                        rev = argv[i++];
 230                } else {
 231                        /* Otherwise we treat this as a filename */
 232                        verify_filename(prefix, argv[i]);
 233                }
 234        }
 235
 236        if (get_sha1(rev, sha1))
 237                die("Failed to resolve '%s' as a valid ref.", rev);
 238
 239        commit = lookup_commit_reference(sha1);
 240        if (!commit)
 241                die("Could not parse object '%s'.", rev);
 242        hashcpy(sha1, commit->object.sha1);
 243
 244        /* git reset tree [--] paths... can be used to
 245         * load chosen paths from the tree into the index without
 246         * affecting the working tree nor HEAD. */
 247        if (i < argc) {
 248                if (reset_type == MIXED)
 249                        warning("--mixed option is deprecated with paths.");
 250                else if (reset_type != NONE)
 251                        die("Cannot do %s reset with paths.",
 252                                        reset_type_names[reset_type]);
 253                return read_from_tree(prefix, argv + i, sha1,
 254                                quiet ? REFRESH_QUIET : REFRESH_SAY_CHANGED);
 255        }
 256        if (reset_type == NONE)
 257                reset_type = MIXED; /* by default */
 258
 259        if (reset_type == HARD && is_bare_repository())
 260                die("hard reset makes no sense in a bare repository");
 261
 262        /* Soft reset does not touch the index file nor the working tree
 263         * at all, but requires them in a good order.  Other resets reset
 264         * the index file to the tree object we are switching to. */
 265        if (reset_type == SOFT) {
 266                if (is_merge() || read_cache() < 0 || unmerged_cache())
 267                        die("Cannot do a soft reset in the middle of a merge.");
 268        }
 269        else if (reset_index_file(sha1, (reset_type == HARD), quiet))
 270                die("Could not reset index file to revision '%s'.", rev);
 271
 272        /* Any resets update HEAD to the head being switched to,
 273         * saving the previous head in ORIG_HEAD before. */
 274        if (!get_sha1("ORIG_HEAD", sha1_old_orig))
 275                old_orig = sha1_old_orig;
 276        if (!get_sha1("HEAD", sha1_orig)) {
 277                orig = sha1_orig;
 278                prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
 279                update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
 280        }
 281        else if (old_orig)
 282                delete_ref("ORIG_HEAD", old_orig, 0);
 283        prepend_reflog_action("updating HEAD", msg, sizeof(msg));
 284        update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
 285
 286        switch (reset_type) {
 287        case HARD:
 288                if (!update_ref_status && !quiet)
 289                        print_new_head_line(commit);
 290                break;
 291        case SOFT: /* Nothing else to do. */
 292                break;
 293        case MIXED: /* Report what has not been updated. */
 294                update_index_refresh(0, NULL,
 295                                quiet ? REFRESH_QUIET : REFRESH_SAY_CHANGED);
 296                break;
 297        }
 298
 299        remove_branch_state();
 300
 301        free(reflog_action);
 302
 303        return update_ref_status;
 304}