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 too_many_loose_objects(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         if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
  84                 warning("insanely long object directory %.*s", 50, objdir);
  85                 return 0;
  86         }
  87         dir = opendir(path);
  88         if (!dir)
  89                 return 0;
  90
  91         auto_threshold = (gc_auto_threshold + 255) / 256;
  92         while ((ent = readdir(dir)) != NULL) {
  93                 if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
  94                     ent->d_name[38] != '\0')
  95                         continue;
  96                 if (++num_loose > auto_threshold) {
  97                         needed = 1;
  98                         break;
  99                 }
 100         }
 101         closedir(dir);
 102         return needed;
 103 }
 104
 105 static int need_to_gc(void)
 106 {
 107         /*
 108          * Setting gc.auto to 0 or negative can disable the
 109          * automatic gc
 110          */
 111         if (gc_auto_threshold <= 0)
 112                 return 0;
 113
 114         return too_many_loose_objects();
 115 }
 116
 117 int cmd_gc(int argc, const char **argv, const char *prefix)
 118 {
 119         int i;
 120         int prune = 0;
 121         int auto_gc = 0;
 122         char buf[80];
 123
 124         git_config(gc_config);
 125
 126         if (pack_refs < 0)
 127                 pack_refs = !is_bare_repository();
 128
 129         for (i = 1; i < argc; i++) {
 130                 const char *arg = argv[i];
 131                 if (!strcmp(arg, "--prune")) {
 132                         prune = 1;
 133                         continue;
 134                 }
 135                 if (!strcmp(arg, "--aggressive")) {
 136                         append_option(argv_repack, "-f", MAX_ADD);
 137                         if (aggressive_window > 0) {
 138                                 sprintf(buf, "--window=%d", aggressive_window);
 139                                 append_option(argv_repack, buf, MAX_ADD);
 140                         }
 141                         continue;
 142                 }
 143                 if (!strcmp(arg, "--auto")) {
 144                         auto_gc = 1;
 145                         continue;
 146                 }
 147                 break;
 148         }
 149         if (i != argc)
 150                 usage(builtin_gc_usage);
 151
 152         if (auto_gc) {
 153                 /*
 154                  * Auto-gc should be least intrusive as possible.
 155                  */
 156                 prune = 0;
 157                 for (i = 0; i < ARRAY_SIZE(argv_repack_auto); i++)
 158                         argv_repack[i] = argv_repack_auto[i];
 159                 if (!need_to_gc())
 160                         return 0;
 161         }
 162
 163         if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))
 164                 return error(FAILED_RUN, argv_pack_refs[0]);
 165
 166         if (run_command_v_opt(argv_reflog, RUN_GIT_CMD))
 167                 return error(FAILED_RUN, argv_reflog[0]);
 168
 169         if (run_command_v_opt(argv_repack, RUN_GIT_CMD))
 170                 return error(FAILED_RUN, argv_repack[0]);
 171
 172         if (prune && run_command_v_opt(argv_prune, RUN_GIT_CMD))
 173                 return error(FAILED_RUN, argv_prune[0]);
 174
 175         if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))
 176                 return error(FAILED_RUN, argv_rerere[0]);
 177
 178         if (auto_gc && too_many_loose_objects())
 179                 warning("There are too many unreachable loose objects; "
 180                         "run 'git prune' to remove them.");
 181
 182         return 0;
 183 }