Andrew's git / gitweb.git / builtin-gc.c
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builtin-gc.con commit Documentation: Describe other situations where -z affects git diff (03aa87e)
   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 = 250;
  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                if (!p->pack_local)
 135                        continue;
 136                if (p->pack_keep)
 137                        continue;
 138                /*
 139                 * Perhaps check the size of the pack and count only
 140                 * very small ones here?
 141                 */
 142                cnt++;
 143        }
 144        return gc_auto_pack_limit <= cnt;
 145}
 146
 147static int need_to_gc(void)
 148{
 149        /*
 150         * Setting gc.auto to 0 or negative can disable the
 151         * automatic gc.
 152         */
 153        if (gc_auto_threshold <= 0)
 154                return 0;
 155
 156        /*
 157         * If there are too many loose objects, but not too many
 158         * packs, we run "repack -d -l".  If there are too many packs,
 159         * we run "repack -A -d -l".  Otherwise we tell the caller
 160         * there is no need.
 161         */
 162        if (too_many_packs())
 163                append_option(argv_repack,
 164                              prune_expire && !strcmp(prune_expire, "now") ?
 165                              "-a" : "-A",
 166                              MAX_ADD);
 167        else if (!too_many_loose_objects())
 168                return 0;
 169
 170        if (run_hook(NULL, "pre-auto-gc", NULL))
 171                return 0;
 172        return 1;
 173}
 174
 175int cmd_gc(int argc, const char **argv, const char *prefix)
 176{
 177        int aggressive = 0;
 178        int auto_gc = 0;
 179        int quiet = 0;
 180        char buf[80];
 181
 182        struct option builtin_gc_options[] = {
 183                OPT__QUIET(&quiet),
 184                { OPTION_STRING, 0, "prune", &prune_expire, "date",
 185                        "prune unreferenced objects",
 186                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 187                OPT_BOOLEAN(0, "aggressive", &aggressive, "be more thorough (increased runtime)"),
 188                OPT_BOOLEAN(0, "auto", &auto_gc, "enable auto-gc mode"),
 189                OPT_END()
 190        };
 191
 192        git_config(gc_config, NULL);
 193
 194        if (pack_refs < 0)
 195                pack_refs = !is_bare_repository();
 196
 197        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 198                             builtin_gc_usage, 0);
 199        if (argc > 0)
 200                usage_with_options(builtin_gc_usage, builtin_gc_options);
 201
 202        if (aggressive) {
 203                append_option(argv_repack, "-f", MAX_ADD);
 204                append_option(argv_repack, "--depth=250", MAX_ADD);
 205                if (aggressive_window > 0) {
 206                        sprintf(buf, "--window=%d", aggressive_window);
 207                        append_option(argv_repack, buf, MAX_ADD);
 208                }
 209        }
 210        if (quiet)
 211                append_option(argv_repack, "-q", MAX_ADD);
 212
 213        if (auto_gc) {
 214                /*
 215                 * Auto-gc should be least intrusive as possible.
 216                 */
 217                if (!need_to_gc())
 218                        return 0;
 219                fprintf(stderr,
 220                        "Auto packing the repository for optimum performance.%s\n",
 221                        quiet
 222                        ? ""
 223                        : (" You may also\n"
 224                           "run \"git gc\" manually. See "
 225                           "\"git help gc\" for more information."));
 226        } else
 227                append_option(argv_repack,
 228                              prune_expire && !strcmp(prune_expire, "now")
 229                              ? "-a" : "-A",
 230                              MAX_ADD);
 231
 232        if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))
 233                return error(FAILED_RUN, argv_pack_refs[0]);
 234
 235        if (run_command_v_opt(argv_reflog, RUN_GIT_CMD))
 236                return error(FAILED_RUN, argv_reflog[0]);
 237
 238        if (run_command_v_opt(argv_repack, RUN_GIT_CMD))
 239                return error(FAILED_RUN, argv_repack[0]);
 240
 241        if (prune_expire) {
 242                argv_prune[2] = prune_expire;
 243                if (run_command_v_opt(argv_prune, RUN_GIT_CMD))
 244                        return error(FAILED_RUN, argv_prune[0]);
 245        }
 246
 247        if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))
 248                return error(FAILED_RUN, argv_rerere[0]);
 249
 250        if (auto_gc && too_many_loose_objects())
 251                warning("There are too many unreachable loose objects; "
 252                        "run 'git prune' to remove them.");
 253
 254        return 0;
 255}