builtin-gc.c

   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
  20 static const char * const builtin_gc_usage[] = {
  21         "git gc [options]",
  22         NULL
  23 };
  24
  25 static int pack_refs = 1;
  26 static int aggressive_window = 250;
  27 static int gc_auto_threshold = 6700;
  28 static int gc_auto_pack_limit = 50;
  29 static const char *prune_expire = "2.weeks.ago";
  30
  31 #define MAX_ADD 10
  32 static const char *argv_pack_refs[] = {"pack-refs", "--all", "--prune", NULL};
  33 static const char *argv_reflog[] = {"reflog", "expire", "--all", NULL};
  34 static const char *argv_repack[MAX_ADD] = {"repack", "-d", "-l", NULL};
  35 static const char *argv_prune[] = {"prune", "--expire", NULL, NULL};
  36 static const char *argv_rerere[] = {"rerere", "gc", NULL};
  37
  38 static 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
  70 static 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
  83 static 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
 124 static 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
 147 static 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
 175 int 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 }