Merge branch 'nv/doc-config-signingkey'
[git] / 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 #include "argv-array.h"
18
19 #define FAILED_RUN "failed to run %s"
20
21 static const char * const builtin_gc_usage[] = {
22         N_("git gc [options]"),
23         NULL
24 };
25
26 static int pack_refs = 1;
27 static int aggressive_window = 250;
28 static int gc_auto_threshold = 6700;
29 static int gc_auto_pack_limit = 50;
30 static const char *prune_expire = "2.weeks.ago";
31
32 static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
33 static struct argv_array reflog = ARGV_ARRAY_INIT;
34 static struct argv_array repack = ARGV_ARRAY_INIT;
35 static struct argv_array prune = ARGV_ARRAY_INIT;
36 static struct argv_array rerere = ARGV_ARRAY_INIT;
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 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
111 static 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                 if (!p->pack_local)
122                         continue;
123                 if (p->pack_keep)
124                         continue;
125                 /*
126                  * Perhaps check the size of the pack and count only
127                  * very small ones here?
128                  */
129                 cnt++;
130         }
131         return gc_auto_pack_limit <= cnt;
132 }
133
134 static void add_repack_all_option(void)
135 {
136         if (prune_expire && !strcmp(prune_expire, "now"))
137                 argv_array_push(&repack, "-a");
138         else {
139                 argv_array_push(&repack, "-A");
140                 if (prune_expire)
141                         argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
142         }
143 }
144
145 static int need_to_gc(void)
146 {
147         /*
148          * Setting gc.auto to 0 or negative can disable the
149          * automatic gc.
150          */
151         if (gc_auto_threshold <= 0)
152                 return 0;
153
154         /*
155          * If there are too many loose objects, but not too many
156          * packs, we run "repack -d -l".  If there are too many packs,
157          * we run "repack -A -d -l".  Otherwise we tell the caller
158          * there is no need.
159          */
160         if (too_many_packs())
161                 add_repack_all_option();
162         else if (!too_many_loose_objects())
163                 return 0;
164
165         if (run_hook(NULL, "pre-auto-gc", NULL))
166                 return 0;
167         return 1;
168 }
169
170 /* return NULL on success, else hostname running the gc */
171 static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
172 {
173         static struct lock_file lock;
174         static char locking_host[128];
175         char my_host[128];
176         struct strbuf sb = STRBUF_INIT;
177         struct stat st;
178         uintmax_t pid;
179         FILE *fp;
180         int fd, should_exit;
181
182         if (gethostname(my_host, sizeof(my_host)))
183                 strcpy(my_host, "unknown");
184
185         fd = hold_lock_file_for_update(&lock, git_path("gc.pid"),
186                                        LOCK_DIE_ON_ERROR);
187         if (!force) {
188                 fp = fopen(git_path("gc.pid"), "r");
189                 memset(locking_host, 0, sizeof(locking_host));
190                 should_exit =
191                         fp != NULL &&
192                         !fstat(fileno(fp), &st) &&
193                         /*
194                          * 12 hour limit is very generous as gc should
195                          * never take that long. On the other hand we
196                          * don't really need a strict limit here,
197                          * running gc --auto one day late is not a big
198                          * problem. --force can be used in manual gc
199                          * after the user verifies that no gc is
200                          * running.
201                          */
202                         time(NULL) - st.st_mtime <= 12 * 3600 &&
203                         fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 &&
204                         /* be gentle to concurrent "gc" on remote hosts */
205                         (strcmp(locking_host, my_host) || !kill(pid, 0));
206                 if (fp != NULL)
207                         fclose(fp);
208                 if (should_exit) {
209                         if (fd >= 0)
210                                 rollback_lock_file(&lock);
211                         *ret_pid = pid;
212                         return locking_host;
213                 }
214         }
215
216         strbuf_addf(&sb, "%"PRIuMAX" %s",
217                     (uintmax_t) getpid(), my_host);
218         write_in_full(fd, sb.buf, sb.len);
219         strbuf_release(&sb);
220         commit_lock_file(&lock);
221
222         return NULL;
223 }
224
225 int cmd_gc(int argc, const char **argv, const char *prefix)
226 {
227         int aggressive = 0;
228         int auto_gc = 0;
229         int quiet = 0;
230         int force = 0;
231         const char *name;
232         pid_t pid;
233
234         struct option builtin_gc_options[] = {
235                 OPT__QUIET(&quiet, N_("suppress progress reporting")),
236                 { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
237                         N_("prune unreferenced objects"),
238                         PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
239                 OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
240                 OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
241                 OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
242                 OPT_END()
243         };
244
245         if (argc == 2 && !strcmp(argv[1], "-h"))
246                 usage_with_options(builtin_gc_usage, builtin_gc_options);
247
248         argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
249         argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
250         argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
251         argv_array_pushl(&prune, "prune", "--expire", NULL );
252         argv_array_pushl(&rerere, "rerere", "gc", NULL);
253
254         git_config(gc_config, NULL);
255
256         if (pack_refs < 0)
257                 pack_refs = !is_bare_repository();
258
259         argc = parse_options(argc, argv, prefix, builtin_gc_options,
260                              builtin_gc_usage, 0);
261         if (argc > 0)
262                 usage_with_options(builtin_gc_usage, builtin_gc_options);
263
264         if (aggressive) {
265                 argv_array_push(&repack, "-f");
266                 argv_array_push(&repack, "--depth=250");
267                 if (aggressive_window > 0)
268                         argv_array_pushf(&repack, "--window=%d", aggressive_window);
269         }
270         if (quiet)
271                 argv_array_push(&repack, "-q");
272
273         if (auto_gc) {
274                 /*
275                  * Auto-gc should be least intrusive as possible.
276                  */
277                 if (!need_to_gc())
278                         return 0;
279                 if (!quiet)
280                         fprintf(stderr,
281                                         _("Auto packing the repository for optimum performance. You may also\n"
282                                         "run \"git gc\" manually. See "
283                                         "\"git help gc\" for more information.\n"));
284         } else
285                 add_repack_all_option();
286
287         name = lock_repo_for_gc(force, &pid);
288         if (name) {
289                 if (auto_gc)
290                         return 0; /* be quiet on --auto */
291                 die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
292                     name, (uintmax_t)pid);
293         }
294
295         if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
296                 return error(FAILED_RUN, pack_refs_cmd.argv[0]);
297
298         if (run_command_v_opt(reflog.argv, RUN_GIT_CMD))
299                 return error(FAILED_RUN, reflog.argv[0]);
300
301         if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
302                 return error(FAILED_RUN, repack.argv[0]);
303
304         if (prune_expire) {
305                 argv_array_push(&prune, prune_expire);
306                 if (quiet)
307                         argv_array_push(&prune, "--no-progress");
308                 if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
309                         return error(FAILED_RUN, prune.argv[0]);
310         }
311
312         if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
313                 return error(FAILED_RUN, rerere.argv[0]);
314
315         if (auto_gc && too_many_loose_objects())
316                 warning(_("There are too many unreachable loose objects; "
317                         "run 'git prune' to remove them."));
318
319         return 0;
320 }