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 "run-command.h"
  16
  17#define FAILED_RUN "failed to run %s"
  18
  19static const char builtin_gc_usage[] = "git-gc [--prune] [--aggressive]";
  20
  21static int pack_refs = 1;
  22static int aggressive_window = -1;
  23static int gc_auto_threshold = 6700;
  24static int gc_auto_pack_limit = 20;
  25
  26#define MAX_ADD 10
  27static const char *argv_pack_refs[] = {"pack-refs", "--all", "--prune", NULL};
  28static const char *argv_reflog[] = {"reflog", "expire", "--all", NULL};
  29static const char *argv_repack[MAX_ADD] = {"repack", "-a", "-d", "-l", NULL};
  30static const char *argv_prune[] = {"prune", NULL};
  31static const char *argv_rerere[] = {"rerere", "gc", NULL};
  32
  33static int gc_config(const char *var, const char *value)
  34{
  35        if (!strcmp(var, "gc.packrefs")) {
  36                if (!strcmp(value, "notbare"))
  37                        pack_refs = -1;
  38                else
  39                        pack_refs = git_config_bool(var, value);
  40                return 0;
  41        }
  42        if (!strcmp(var, "gc.aggressivewindow")) {
  43                aggressive_window = git_config_int(var, value);
  44                return 0;
  45        }
  46        if (!strcmp(var, "gc.auto")) {
  47                gc_auto_threshold = git_config_int(var, value);
  48                return 0;
  49        }
  50        if (!strcmp(var, "gc.autopacklimit")) {
  51                gc_auto_pack_limit = git_config_int(var, value);
  52                return 0;
  53        }
  54        return git_default_config(var, value);
  55}
  56
  57static void append_option(const char **cmd, const char *opt, int max_length)
  58{
  59        int i;
  60
  61        for (i = 0; cmd[i]; i++)
  62                ;
  63
  64        if (i + 2 >= max_length)
  65                die("Too many options specified");
  66        cmd[i++] = opt;
  67        cmd[i] = NULL;
  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                char path[PATH_MAX];
 122                size_t len;
 123                int keep;
 124
 125                if (!p->pack_local)
 126                        continue;
 127                len = strlen(p->pack_name);
 128                if (PATH_MAX <= len + 1)
 129                        continue; /* oops, give up */
 130                memcpy(path, p->pack_name, len-5);
 131                memcpy(path + len - 5, ".keep", 6);
 132                keep = access(p->pack_name, F_OK) && (errno == ENOENT);
 133                if (keep)
 134                        continue;
 135                /*
 136                 * Perhaps check the size of the pack and count only
 137                 * very small ones here?
 138                 */
 139                cnt++;
 140        }
 141        return gc_auto_pack_limit <= cnt;
 142}
 143
 144static int need_to_gc(void)
 145{
 146        int ac = 0;
 147
 148        /*
 149         * Setting gc.auto and gc.autopacklimit to 0 or negative can
 150         * disable the automatic gc.
 151         */
 152        if (gc_auto_threshold <= 0 && gc_auto_pack_limit <= 0)
 153                return 0;
 154
 155        /*
 156         * If there are too many loose objects, but not too many
 157         * packs, we run "repack -d -l".  If there are too many packs,
 158         * we run "repack -A -d -l".  Otherwise we tell the caller
 159         * there is no need.
 160         */
 161        argv_repack[ac++] = "repack";
 162        if (too_many_packs())
 163                argv_repack[ac++] = "-A";
 164        else if (!too_many_loose_objects())
 165                return 0;
 166        argv_repack[ac++] = "-d";
 167        argv_repack[ac++] = "-l";
 168        argv_repack[ac++] = NULL;
 169        return 1;
 170}
 171
 172int cmd_gc(int argc, const char **argv, const char *prefix)
 173{
 174        int i;
 175        int prune = 0;
 176        int auto_gc = 0;
 177        char buf[80];
 178
 179        git_config(gc_config);
 180
 181        if (pack_refs < 0)
 182                pack_refs = !is_bare_repository();
 183
 184        for (i = 1; i < argc; i++) {
 185                const char *arg = argv[i];
 186                if (!strcmp(arg, "--prune")) {
 187                        prune = 1;
 188                        continue;
 189                }
 190                if (!strcmp(arg, "--aggressive")) {
 191                        append_option(argv_repack, "-f", MAX_ADD);
 192                        if (aggressive_window > 0) {
 193                                sprintf(buf, "--window=%d", aggressive_window);
 194                                append_option(argv_repack, buf, MAX_ADD);
 195                        }
 196                        continue;
 197                }
 198                if (!strcmp(arg, "--auto")) {
 199                        auto_gc = 1;
 200                        continue;
 201                }
 202                break;
 203        }
 204        if (i != argc)
 205                usage(builtin_gc_usage);
 206
 207        if (auto_gc) {
 208                /*
 209                 * Auto-gc should be least intrusive as possible.
 210                 */
 211                prune = 0;
 212                if (!need_to_gc())
 213                        return 0;
 214        }
 215
 216        if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))
 217                return error(FAILED_RUN, argv_pack_refs[0]);
 218
 219        if (run_command_v_opt(argv_reflog, RUN_GIT_CMD))
 220                return error(FAILED_RUN, argv_reflog[0]);
 221
 222        if (run_command_v_opt(argv_repack, RUN_GIT_CMD))
 223                return error(FAILED_RUN, argv_repack[0]);
 224
 225        if (prune && run_command_v_opt(argv_prune, RUN_GIT_CMD))
 226                return error(FAILED_RUN, argv_prune[0]);
 227
 228        if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))
 229                return error(FAILED_RUN, argv_rerere[0]);
 230
 231        if (auto_gc && too_many_loose_objects())
 232                warning("There are too many unreachable loose objects; "
 233                        "run 'git prune' to remove them.");
 234
 235        return 0;
 236}