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 "run-command.h"
  16
  17 #define FAILED_RUN "failed to run %s"
  18
  19 static const char builtin_gc_usage[] = "git-gc [--prune] [--aggressive]";
  20
  21 static int pack_refs = 1;
  22 static int aggressive_window = -1;
  23 static int gc_auto_threshold = 6700;
  24
  25 #define MAX_ADD 10
  26 static const char *argv_pack_refs[] = {"pack-refs", "--all", "--prune", NULL};
  27 static const char *argv_reflog[] = {"reflog", "expire", "--all", NULL};
  28 static const char *argv_repack[MAX_ADD] = {"repack", "-a", "-d", "-l", NULL};
  29 static const char *argv_prune[] = {"prune", NULL};
  30 static const char *argv_rerere[] = {"rerere", "gc", NULL};
  31
  32 static const char *argv_repack_auto[] = {"repack", "-d", "-l", NULL};
  33
  34 static int gc_config(const char *var, const char *value)
  35 {
  36         if (!strcmp(var, "gc.packrefs")) {
  37                 if (!strcmp(value, "notbare"))
  38                         pack_refs = -1;
  39                 else
  40                         pack_refs = git_config_bool(var, value);
  41                 return 0;
  42         }
  43         if (!strcmp(var, "gc.aggressivewindow")) {
  44                 aggressive_window = git_config_int(var, value);
  45                 return 0;
  46         }
  47         if (!strcmp(var, "gc.auto")) {
  48                 gc_auto_threshold = git_config_int(var, value);
  49                 return 0;
  50         }
  51         return git_default_config(var, value);
  52 }
  53
  54 static void append_option(const char **cmd, const char *opt, int max_length)
  55 {
  56         int i;
  57
  58         for (i = 0; cmd[i]; i++)
  59                 ;
  60
  61         if (i + 2 >= max_length)
  62                 die("Too many options specified");
  63         cmd[i++] = opt;
  64         cmd[i] = NULL;
  65 }
  66
  67 static int need_to_gc(void)
  68 {
  69         /*
  70          * Quickly check if a "gc" is needed, by estimating how
  71          * many loose objects there are.  Because SHA-1 is evenly
  72          * distributed, we can check only one and get a reasonable
  73          * estimate.
  74          */
  75         char path[PATH_MAX];
  76         const char *objdir = get_object_directory();
  77         DIR *dir;
  78         struct dirent *ent;
  79         int auto_threshold;
  80         int num_loose = 0;
  81         int needed = 0;
  82
  83         /*
  84          * Setting gc.auto to 0 or negative can disable the
  85          * automatic gc
  86          */
  87         if (gc_auto_threshold <= 0)
  88                 return 0;
  89
  90         if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
  91                 warning("insanely long object directory %.*s", 50, objdir);
  92                 return 0;
  93         }
  94         dir = opendir(path);
  95         if (!dir)
  96                 return 0;
  97
  98         auto_threshold = (gc_auto_threshold + 255) / 256;
  99         while ((ent = readdir(dir)) != NULL) {
 100                 if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 101                     ent->d_name[38] != '\0')
 102                         continue;
 103                 if (++num_loose > auto_threshold) {
 104                         needed = 1;
 105                         break;
 106                 }
 107         }
 108         closedir(dir);
 109         return needed;
 110 }
 111
 112 int cmd_gc(int argc, const char **argv, const char *prefix)
 113 {
 114         int i;
 115         int prune = 0;
 116         int auto_gc = 0;
 117         char buf[80];
 118
 119         git_config(gc_config);
 120
 121         if (pack_refs < 0)
 122                 pack_refs = !is_bare_repository();
 123
 124         for (i = 1; i < argc; i++) {
 125                 const char *arg = argv[i];
 126                 if (!strcmp(arg, "--prune")) {
 127                         prune = 1;
 128                         continue;
 129                 }
 130                 if (!strcmp(arg, "--aggressive")) {
 131                         append_option(argv_repack, "-f", MAX_ADD);
 132                         if (aggressive_window > 0) {
 133                                 sprintf(buf, "--window=%d", aggressive_window);
 134                                 append_option(argv_repack, buf, MAX_ADD);
 135                         }
 136                         continue;
 137                 }
 138                 if (!strcmp(arg, "--auto")) {
 139                         auto_gc = 1;
 140                         continue;
 141                 }
 142                 break;
 143         }
 144         if (i != argc)
 145                 usage(builtin_gc_usage);
 146
 147         if (auto_gc) {
 148                 /*
 149                  * Auto-gc should be least intrusive as possible.
 150                  */
 151                 prune = 0;
 152                 for (i = 0; i < ARRAY_SIZE(argv_repack_auto); i++)
 153                         argv_repack[i] = argv_repack_auto[i];
 154                 if (!need_to_gc())
 155                         return 0;
 156         }
 157
 158         if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))
 159                 return error(FAILED_RUN, argv_pack_refs[0]);
 160
 161         if (run_command_v_opt(argv_reflog, RUN_GIT_CMD))
 162                 return error(FAILED_RUN, argv_reflog[0]);
 163
 164         if (run_command_v_opt(argv_repack, RUN_GIT_CMD))
 165                 return error(FAILED_RUN, argv_repack[0]);
 166
 167         if (prune && run_command_v_opt(argv_prune, RUN_GIT_CMD))
 168                 return error(FAILED_RUN, argv_prune[0]);
 169
 170         if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))
 171                 return error(FAILED_RUN, argv_rerere[0]);
 172
 173         return 0;
 174 }