Merge branch 'maint'
[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
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 = -1;
27 static int gc_auto_threshold = 6700;
28 static int gc_auto_pack_limit = 50;
29 static 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)
61                         return config_error_nonbool(var);
62                 if (strcmp(value, "now")) {
63                         unsigned long now = approxidate("now");
64                         if (approxidate(value) >= now)
65                                 return error("Invalid %s: '%s'", var, value);
66                 }
67                 prune_expire = xstrdup(value);
68                 return 0;
69         }
70         return git_default_config(var, value, cb);
71 }
72
73 static void append_option(const char **cmd, const char *opt, int max_length)
74 {
75         int i;
76
77         for (i = 0; cmd[i]; i++)
78                 ;
79
80         if (i + 2 >= max_length)
81                 die("Too many options specified");
82         cmd[i++] = opt;
83         cmd[i] = NULL;
84 }
85
86 static int too_many_loose_objects(void)
87 {
88         /*
89          * Quickly check if a "gc" is needed, by estimating how
90          * many loose objects there are.  Because SHA-1 is evenly
91          * distributed, we can check only one and get a reasonable
92          * estimate.
93          */
94         char path[PATH_MAX];
95         const char *objdir = get_object_directory();
96         DIR *dir;
97         struct dirent *ent;
98         int auto_threshold;
99         int num_loose = 0;
100         int needed = 0;
101
102         if (gc_auto_threshold <= 0)
103                 return 0;
104
105         if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
106                 warning("insanely long object directory %.*s", 50, objdir);
107                 return 0;
108         }
109         dir = opendir(path);
110         if (!dir)
111                 return 0;
112
113         auto_threshold = (gc_auto_threshold + 255) / 256;
114         while ((ent = readdir(dir)) != NULL) {
115                 if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
116                     ent->d_name[38] != '\0')
117                         continue;
118                 if (++num_loose > auto_threshold) {
119                         needed = 1;
120                         break;
121                 }
122         }
123         closedir(dir);
124         return needed;
125 }
126
127 static int too_many_packs(void)
128 {
129         struct packed_git *p;
130         int cnt;
131
132         if (gc_auto_pack_limit <= 0)
133                 return 0;
134
135         prepare_packed_git();
136         for (cnt = 0, p = packed_git; p; p = p->next) {
137                 char path[PATH_MAX];
138                 size_t len;
139                 int keep;
140
141                 if (!p->pack_local)
142                         continue;
143                 len = strlen(p->pack_name);
144                 if (PATH_MAX <= len + 1)
145                         continue; /* oops, give up */
146                 memcpy(path, p->pack_name, len-5);
147                 memcpy(path + len - 5, ".keep", 6);
148                 keep = access(p->pack_name, F_OK) && (errno == ENOENT);
149                 if (keep)
150                         continue;
151                 /*
152                  * Perhaps check the size of the pack and count only
153                  * very small ones here?
154                  */
155                 cnt++;
156         }
157         return gc_auto_pack_limit <= cnt;
158 }
159
160 static int run_hook(void)
161 {
162         const char *argv[2];
163         struct child_process hook;
164         int ret;
165
166         argv[0] = git_path("hooks/pre-auto-gc");
167         argv[1] = NULL;
168
169         if (access(argv[0], X_OK) < 0)
170                 return 0;
171
172         memset(&hook, 0, sizeof(hook));
173         hook.argv = argv;
174         hook.no_stdin = 1;
175         hook.stdout_to_stderr = 1;
176
177         ret = start_command(&hook);
178         if (ret) {
179                 warning("Could not spawn %s", argv[0]);
180                 return ret;
181         }
182         ret = finish_command(&hook);
183         if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
184                 warning("%s exited due to uncaught signal", argv[0]);
185         return ret;
186 }
187
188 static int need_to_gc(void)
189 {
190         /*
191          * Setting gc.auto to 0 or negative can disable the
192          * automatic gc.
193          */
194         if (gc_auto_threshold <= 0)
195                 return 0;
196
197         /*
198          * If there are too many loose objects, but not too many
199          * packs, we run "repack -d -l".  If there are too many packs,
200          * we run "repack -A -d -l".  Otherwise we tell the caller
201          * there is no need.
202          */
203         if (too_many_packs())
204                 append_option(argv_repack, "-A", MAX_ADD);
205         else if (!too_many_loose_objects())
206                 return 0;
207
208         if (run_hook())
209                 return 0;
210         return 1;
211 }
212
213 int cmd_gc(int argc, const char **argv, const char *prefix)
214 {
215         int prune = 0;
216         int aggressive = 0;
217         int auto_gc = 0;
218         int quiet = 0;
219         char buf[80];
220
221         struct option builtin_gc_options[] = {
222                 OPT_BOOLEAN(0, "prune", &prune, "prune unreferenced objects (deprecated)"),
223                 OPT_BOOLEAN(0, "aggressive", &aggressive, "be more thorough (increased runtime)"),
224                 OPT_BOOLEAN(0, "auto", &auto_gc, "enable auto-gc mode"),
225                 OPT_BOOLEAN('q', "quiet", &quiet, "suppress progress reports"),
226                 OPT_END()
227         };
228
229         git_config(gc_config, NULL);
230
231         if (pack_refs < 0)
232                 pack_refs = !is_bare_repository();
233
234         argc = parse_options(argc, argv, builtin_gc_options, builtin_gc_usage, 0);
235         if (argc > 0)
236                 usage_with_options(builtin_gc_usage, builtin_gc_options);
237
238         if (aggressive) {
239                 append_option(argv_repack, "-f", MAX_ADD);
240                 if (aggressive_window > 0) {
241                         sprintf(buf, "--window=%d", aggressive_window);
242                         append_option(argv_repack, buf, MAX_ADD);
243                 }
244         }
245         if (quiet)
246                 append_option(argv_repack, "-q", MAX_ADD);
247
248         if (auto_gc) {
249                 /*
250                  * Auto-gc should be least intrusive as possible.
251                  */
252                 if (!need_to_gc())
253                         return 0;
254                 fprintf(stderr, "Auto packing your repository for optimum "
255                         "performance. You may also\n"
256                         "run \"git gc\" manually. See "
257                         "\"git help gc\" for more information.\n");
258         } else
259                 append_option(argv_repack, "-A", MAX_ADD);
260
261         if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))
262                 return error(FAILED_RUN, argv_pack_refs[0]);
263
264         if (run_command_v_opt(argv_reflog, RUN_GIT_CMD))
265                 return error(FAILED_RUN, argv_reflog[0]);
266
267         if (run_command_v_opt(argv_repack, RUN_GIT_CMD))
268                 return error(FAILED_RUN, argv_repack[0]);
269
270         argv_prune[2] = prune_expire;
271         if (run_command_v_opt(argv_prune, RUN_GIT_CMD))
272                 return error(FAILED_RUN, argv_prune[0]);
273
274         if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))
275                 return error(FAILED_RUN, argv_rerere[0]);
276
277         if (auto_gc && too_many_loose_objects())
278                 warning("There are too many unreachable loose objects; "
279                         "run 'git prune' to remove them.");
280
281         return 0;
282 }