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
  18#define FAILED_RUN "failed to run %s"
  19
  20static const char * const builtin_gc_usage[] = {
  21        "git gc [options]",
  22        NULL
  23};
  24
  25static int pack_refs = 1;
  26static int aggressive_window = -1;
  27static int gc_auto_threshold = 6700;
  28static int gc_auto_pack_limit = 50;
  29static const char *prune_expire = "2.weeks.ago";
  30
  31#define MAX_ADD 10
  32static const char *argv_pack_refs[] = {"pack-refs", "--all", "--prune", NULL};
  33static const char *argv_reflog[] = {"reflog", "expire", "--all", NULL};
  34static const char *argv_repack[MAX_ADD] = {"repack", "-d", "-l", NULL};
  35static const char *argv_prune[] = {"prune", "--expire", NULL, NULL};
  36static const char *argv_rerere[] = {"rerere", "gc", NULL};
  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 void append_option(const char **cmd, const char *opt, int max_length)
  71{
  72        int i;
  73
  74        for (i = 0; cmd[i]; i++)
  75                ;
  76
  77        if (i + 2 >= max_length)
  78                die("Too many options specified");
  79        cmd[i++] = opt;
  80        cmd[i] = NULL;
  81}
  82
  83static int too_many_loose_objects(void)
  84{
  85        /*
  86         * Quickly check if a "gc" is needed, by estimating how
  87         * many loose objects there are.  Because SHA-1 is evenly
  88         * distributed, we can check only one and get a reasonable
  89         * estimate.
  90         */
  91        char path[PATH_MAX];
  92        const char *objdir = get_object_directory();
  93        DIR *dir;
  94        struct dirent *ent;
  95        int auto_threshold;
  96        int num_loose = 0;
  97        int needed = 0;
  98
  99        if (gc_auto_threshold <= 0)
 100                return 0;
 101
 102        if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 103                warning("insanely long object directory %.*s", 50, objdir);
 104                return 0;
 105        }
 106        dir = opendir(path);
 107        if (!dir)
 108                return 0;
 109
 110        auto_threshold = (gc_auto_threshold + 255) / 256;
 111        while ((ent = readdir(dir)) != NULL) {
 112                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 113                    ent->d_name[38] != '\0')
 114                        continue;
 115                if (++num_loose > auto_threshold) {
 116                        needed = 1;
 117                        break;
 118                }
 119        }
 120        closedir(dir);
 121        return needed;
 122}
 123
 124static int too_many_packs(void)
 125{
 126        struct packed_git *p;
 127        int cnt;
 128
 129        if (gc_auto_pack_limit <= 0)
 130                return 0;
 131
 132        prepare_packed_git();
 133        for (cnt = 0, p = packed_git; p; p = p->next) {
 134                char path[PATH_MAX];
 135                size_t len;
 136                int keep;
 137
 138                if (!p->pack_local)
 139                        continue;
 140                len = strlen(p->pack_name);
 141                if (PATH_MAX <= len + 1)
 142                        continue; /* oops, give up */
 143                memcpy(path, p->pack_name, len-5);
 144                memcpy(path + len - 5, ".keep", 6);
 145                keep = access(p->pack_name, F_OK) && (errno == ENOENT);
 146                if (keep)
 147                        continue;
 148                /*
 149                 * Perhaps check the size of the pack and count only
 150                 * very small ones here?
 151                 */
 152                cnt++;
 153        }
 154        return gc_auto_pack_limit <= cnt;
 155}
 156
 157static int run_hook(void)
 158{
 159        const char *argv[2];
 160        struct child_process hook;
 161        int ret;
 162
 163        argv[0] = git_path("hooks/pre-auto-gc");
 164        argv[1] = NULL;
 165
 166        if (access(argv[0], X_OK) < 0)
 167                return 0;
 168
 169        memset(&hook, 0, sizeof(hook));
 170        hook.argv = argv;
 171        hook.no_stdin = 1;
 172        hook.stdout_to_stderr = 1;
 173
 174        ret = start_command(&hook);
 175        if (ret) {
 176                warning("Could not spawn %s", argv[0]);
 177                return ret;
 178        }
 179        ret = finish_command(&hook);
 180        if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
 181                warning("%s exited due to uncaught signal", argv[0]);
 182        return ret;
 183}
 184
 185static int need_to_gc(void)
 186{
 187        /*
 188         * Setting gc.auto to 0 or negative can disable the
 189         * automatic gc.
 190         */
 191        if (gc_auto_threshold <= 0)
 192                return 0;
 193
 194        /*
 195         * If there are too many loose objects, but not too many
 196         * packs, we run "repack -d -l".  If there are too many packs,
 197         * we run "repack -A -d -l".  Otherwise we tell the caller
 198         * there is no need.
 199         */
 200        if (too_many_packs())
 201                append_option(argv_repack, "-A", MAX_ADD);
 202        else if (!too_many_loose_objects())
 203                return 0;
 204
 205        if (run_hook())
 206                return 0;
 207        return 1;
 208}
 209
 210int cmd_gc(int argc, const char **argv, const char *prefix)
 211{
 212        int prune = 0;
 213        int aggressive = 0;
 214        int auto_gc = 0;
 215        int quiet = 0;
 216        char buf[80];
 217
 218        struct option builtin_gc_options[] = {
 219                OPT_BOOLEAN(0, "prune", &prune, "prune unreferenced objects (deprecated)"),
 220                OPT_BOOLEAN(0, "aggressive", &aggressive, "be more thorough (increased runtime)"),
 221                OPT_BOOLEAN(0, "auto", &auto_gc, "enable auto-gc mode"),
 222                OPT_BOOLEAN('q', "quiet", &quiet, "suppress progress reports"),
 223                OPT_END()
 224        };
 225
 226        git_config(gc_config, NULL);
 227
 228        if (pack_refs < 0)
 229                pack_refs = !is_bare_repository();
 230
 231        argc = parse_options(argc, argv, builtin_gc_options, builtin_gc_usage, 0);
 232        if (argc > 0)
 233                usage_with_options(builtin_gc_usage, builtin_gc_options);
 234
 235        if (aggressive) {
 236                append_option(argv_repack, "-f", MAX_ADD);
 237                if (aggressive_window > 0) {
 238                        sprintf(buf, "--window=%d", aggressive_window);
 239                        append_option(argv_repack, buf, MAX_ADD);
 240                }
 241        }
 242        if (quiet)
 243                append_option(argv_repack, "-q", MAX_ADD);
 244
 245        if (auto_gc) {
 246                /*
 247                 * Auto-gc should be least intrusive as possible.
 248                 */
 249                if (!need_to_gc())
 250                        return 0;
 251                fprintf(stderr, "Auto packing your repository for optimum "
 252                        "performance. You may also\n"
 253                        "run \"git gc\" manually. See "
 254                        "\"git help gc\" for more information.\n");
 255        } else
 256                append_option(argv_repack, "-A", MAX_ADD);
 257
 258        if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))
 259                return error(FAILED_RUN, argv_pack_refs[0]);
 260
 261        if (run_command_v_opt(argv_reflog, RUN_GIT_CMD))
 262                return error(FAILED_RUN, argv_reflog[0]);
 263
 264        if (run_command_v_opt(argv_repack, RUN_GIT_CMD))
 265                return error(FAILED_RUN, argv_repack[0]);
 266
 267        argv_prune[2] = prune_expire;
 268        if (run_command_v_opt(argv_prune, RUN_GIT_CMD))
 269                return error(FAILED_RUN, argv_prune[0]);
 270
 271        if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))
 272                return error(FAILED_RUN, argv_rerere[0]);
 273
 274        if (auto_gc && too_many_loose_objects())
 275                warning("There are too many unreachable loose objects; "
 276                        "run 'git prune' to remove them.");
 277
 278        return 0;
 279}