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