Andrew's git - gitweb.git/blob

   1/*
   2 * git gc builtin command
   3 *
   4 * Cleanup unreachable files and optimize the repository.
   5 *
   6 * Copyright (c) 2007 James Bowes
   7 *
   8 * Based on git-gc.sh, which is
   9 *
  10 * Copyright (c) 2006 Shawn O. Pearce
  11 */
  12
  13#include "builtin.h"
  14#include "cache.h"
  15#include "parse-options.h"
  16#include "run-command.h"
  17#include "sigchain.h"
  18#include "argv-array.h"
  19
  20#define FAILED_RUN "failed to run %s"
  21
  22static const char * const builtin_gc_usage[] = {
  23        N_("git gc [options]"),
  24        NULL
  25};
  26
  27static int pack_refs = 1;
  28static int aggressive_window = 250;
  29static int gc_auto_threshold = 6700;
  30static int gc_auto_pack_limit = 50;
  31static const char *prune_expire = "2.weeks.ago";
  32
  33static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  34static struct argv_array reflog = ARGV_ARRAY_INIT;
  35static struct argv_array repack = ARGV_ARRAY_INIT;
  36static struct argv_array prune = ARGV_ARRAY_INIT;
  37static struct argv_array rerere = ARGV_ARRAY_INIT;
  38
  39static char *pidfile;
  40
  41static void remove_pidfile(void)
  42{
  43        if (pidfile)
  44                unlink(pidfile);
  45}
  46
  47static void remove_pidfile_on_signal(int signo)
  48{
  49        remove_pidfile();
  50        sigchain_pop(signo);
  51        raise(signo);
  52}
  53
  54static int gc_config(const char *var, const char *value, void *cb)
  55{
  56        if (!strcmp(var, "gc.packrefs")) {
  57                if (value && !strcmp(value, "notbare"))
  58                        pack_refs = -1;
  59                else
  60                        pack_refs = git_config_bool(var, value);
  61                return 0;
  62        }
  63        if (!strcmp(var, "gc.aggressivewindow")) {
  64                aggressive_window = git_config_int(var, value);
  65                return 0;
  66        }
  67        if (!strcmp(var, "gc.auto")) {
  68                gc_auto_threshold = git_config_int(var, value);
  69                return 0;
  70        }
  71        if (!strcmp(var, "gc.autopacklimit")) {
  72                gc_auto_pack_limit = git_config_int(var, value);
  73                return 0;
  74        }
  75        if (!strcmp(var, "gc.pruneexpire")) {
  76                if (value && strcmp(value, "now")) {
  77                        unsigned long now = approxidate("now");
  78                        if (approxidate(value) >= now)
  79                                return error(_("Invalid %s: '%s'"), var, value);
  80                }
  81                return git_config_string(&prune_expire, var, value);
  82        }
  83        return git_default_config(var, value, cb);
  84}
  85
  86static int too_many_loose_objects(void)
  87{
  88        /*
  89         * Quickly check if a "gc" is needed, by estimating how
  90         * many loose objects there are.  Because SHA-1 is evenly
  91         * distributed, we can check only one and get a reasonable
  92         * estimate.
  93         */
  94        char path[PATH_MAX];
  95        const char *objdir = get_object_directory();
  96        DIR *dir;
  97        struct dirent *ent;
  98        int auto_threshold;
  99        int num_loose = 0;
 100        int needed = 0;
 101
 102        if (gc_auto_threshold <= 0)
 103                return 0;
 104
 105        if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 106                warning(_("insanely long object directory %.*s"), 50, objdir);
 107                return 0;
 108        }
 109        dir = opendir(path);
 110        if (!dir)
 111                return 0;
 112
 113        auto_threshold = (gc_auto_threshold + 255) / 256;
 114        while ((ent = readdir(dir)) != NULL) {
 115                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 116                    ent->d_name[38] != '\0')
 117                        continue;
 118                if (++num_loose > auto_threshold) {
 119                        needed = 1;
 120                        break;
 121                }
 122        }
 123        closedir(dir);
 124        return needed;
 125}
 126
 127static int too_many_packs(void)
 128{
 129        struct packed_git *p;
 130        int cnt;
 131
 132        if (gc_auto_pack_limit <= 0)
 133                return 0;
 134
 135        prepare_packed_git();
 136        for (cnt = 0, p = packed_git; p; p = p->next) {
 137                if (!p->pack_local)
 138                        continue;
 139                if (p->pack_keep)
 140                        continue;
 141                /*
 142                 * Perhaps check the size of the pack and count only
 143                 * very small ones here?
 144                 */
 145                cnt++;
 146        }
 147        return gc_auto_pack_limit <= cnt;
 148}
 149
 150static void add_repack_all_option(void)
 151{
 152        if (prune_expire && !strcmp(prune_expire, "now"))
 153                argv_array_push(&repack, "-a");
 154        else {
 155                argv_array_push(&repack, "-A");
 156                if (prune_expire)
 157                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 158        }
 159}
 160
 161static int need_to_gc(void)
 162{
 163        /*
 164         * Setting gc.auto to 0 or negative can disable the
 165         * automatic gc.
 166         */
 167        if (gc_auto_threshold <= 0)
 168                return 0;
 169
 170        /*
 171         * If there are too many loose objects, but not too many
 172         * packs, we run "repack -d -l".  If there are too many packs,
 173         * we run "repack -A -d -l".  Otherwise we tell the caller
 174         * there is no need.
 175         */
 176        if (too_many_packs())
 177                add_repack_all_option();
 178        else if (!too_many_loose_objects())
 179                return 0;
 180
 181        if (run_hook(NULL, "pre-auto-gc", NULL))
 182                return 0;
 183        return 1;
 184}
 185
 186/* return NULL on success, else hostname running the gc */
 187static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 188{
 189        static struct lock_file lock;
 190        static char locking_host[128];
 191        char my_host[128];
 192        struct strbuf sb = STRBUF_INIT;
 193        struct stat st;
 194        uintmax_t pid;
 195        FILE *fp;
 196        int fd, should_exit;
 197
 198        if (pidfile)
 199                /* already locked */
 200                return NULL;
 201
 202        if (gethostname(my_host, sizeof(my_host)))
 203                strcpy(my_host, "unknown");
 204
 205        fd = hold_lock_file_for_update(&lock, git_path("gc.pid"),
 206                                       LOCK_DIE_ON_ERROR);
 207        if (!force) {
 208                fp = fopen(git_path("gc.pid"), "r");
 209                memset(locking_host, 0, sizeof(locking_host));
 210                should_exit =
 211                        fp != NULL &&
 212                        !fstat(fileno(fp), &st) &&
 213                        /*
 214                         * 12 hour limit is very generous as gc should
 215                         * never take that long. On the other hand we
 216                         * don't really need a strict limit here,
 217                         * running gc --auto one day late is not a big
 218                         * problem. --force can be used in manual gc
 219                         * after the user verifies that no gc is
 220                         * running.
 221                         */
 222                        time(NULL) - st.st_mtime <= 12 * 3600 &&
 223                        fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 &&
 224                        /* be gentle to concurrent "gc" on remote hosts */
 225                        (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 226                if (fp != NULL)
 227                        fclose(fp);
 228                if (should_exit) {
 229                        if (fd >= 0)
 230                                rollback_lock_file(&lock);
 231                        *ret_pid = pid;
 232                        return locking_host;
 233                }
 234        }
 235
 236        strbuf_addf(&sb, "%"PRIuMAX" %s",
 237                    (uintmax_t) getpid(), my_host);
 238        write_in_full(fd, sb.buf, sb.len);
 239        strbuf_release(&sb);
 240        commit_lock_file(&lock);
 241
 242        pidfile = git_pathdup("gc.pid");
 243        sigchain_push_common(remove_pidfile_on_signal);
 244        atexit(remove_pidfile);
 245
 246        return NULL;
 247}
 248
 249int cmd_gc(int argc, const char **argv, const char *prefix)
 250{
 251        int aggressive = 0;
 252        int auto_gc = 0;
 253        int quiet = 0;
 254        int force = 0;
 255        const char *name;
 256        pid_t pid;
 257
 258        struct option builtin_gc_options[] = {
 259                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 260                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 261                        N_("prune unreferenced objects"),
 262                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 263                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 264                OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
 265                OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
 266                OPT_END()
 267        };
 268
 269        if (argc == 2 && !strcmp(argv[1], "-h"))
 270                usage_with_options(builtin_gc_usage, builtin_gc_options);
 271
 272        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 273        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 274        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 275        argv_array_pushl(&prune, "prune", "--expire", NULL );
 276        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 277
 278        git_config(gc_config, NULL);
 279
 280        if (pack_refs < 0)
 281                pack_refs = !is_bare_repository();
 282
 283        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 284                             builtin_gc_usage, 0);
 285        if (argc > 0)
 286                usage_with_options(builtin_gc_usage, builtin_gc_options);
 287
 288        if (aggressive) {
 289                argv_array_push(&repack, "-f");
 290                argv_array_push(&repack, "--depth=250");
 291                if (aggressive_window > 0)
 292                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 293        }
 294        if (quiet)
 295                argv_array_push(&repack, "-q");
 296
 297        if (auto_gc) {
 298                /*
 299                 * Auto-gc should be least intrusive as possible.
 300                 */
 301                if (!need_to_gc())
 302                        return 0;
 303                if (!quiet)
 304                        fprintf(stderr,
 305                                        _("Auto packing the repository for optimum performance. You may also\n"
 306                                        "run \"git gc\" manually. See "
 307                                        "\"git help gc\" for more information.\n"));
 308        } else
 309                add_repack_all_option();
 310
 311        name = lock_repo_for_gc(force, &pid);
 312        if (name) {
 313                if (auto_gc)
 314                        return 0; /* be quiet on --auto */
 315                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 316                    name, (uintmax_t)pid);
 317        }
 318
 319        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 320                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 321
 322        if (run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 323                return error(FAILED_RUN, reflog.argv[0]);
 324
 325        if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 326                return error(FAILED_RUN, repack.argv[0]);
 327
 328        if (prune_expire) {
 329                argv_array_push(&prune, prune_expire);
 330                if (quiet)
 331                        argv_array_push(&prune, "--no-progress");
 332                if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 333                        return error(FAILED_RUN, prune.argv[0]);
 334        }
 335
 336        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 337                return error(FAILED_RUN, rerere.argv[0]);
 338
 339        if (auto_gc && too_many_loose_objects())
 340                warning(_("There are too many unreachable loose objects; "
 341                        "run 'git prune' to remove them."));
 342
 343        return 0;
 344}