git-gc --auto: add documentation.
[git/git.git] / builtin-gc.c
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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
baffc0e7 13#include "builtin.h"
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14#include "cache.h"
15#include "run-command.h"
16
17#define FAILED_RUN "failed to run %s"
18
0d7566a5 19static const char builtin_gc_usage[] = "git-gc [--prune] [--aggressive]";
6757ada4 20
56752391 21static int pack_refs = 1;
0d7566a5 22static int aggressive_window = -1;
2c3c4399 23static int gc_auto_threshold = 6700;
6757ada4 24
0d7566a5 25#define MAX_ADD 10
56752391 26static const char *argv_pack_refs[] = {"pack-refs", "--all", "--prune", NULL};
6757ada4 27static const char *argv_reflog[] = {"reflog", "expire", "--all", NULL};
0d7566a5 28static const char *argv_repack[MAX_ADD] = {"repack", "-a", "-d", "-l", NULL};
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29static const char *argv_prune[] = {"prune", NULL};
30static const char *argv_rerere[] = {"rerere", "gc", NULL};
31
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32static const char *argv_repack_auto[] = {"repack", "-d", "-l", NULL};
33
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34static 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 }
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43 if (!strcmp(var, "gc.aggressivewindow")) {
44 aggressive_window = git_config_int(var, value);
45 return 0;
46 }
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47 if (!strcmp(var, "gc.auto")) {
48 gc_auto_threshold = git_config_int(var, value);
49 return 0;
50 }
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51 return git_default_config(var, value);
52}
53
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54static 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
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67static 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
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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
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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
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112int cmd_gc(int argc, const char **argv, const char *prefix)
113{
114 int i;
115 int prune = 0;
2c3c4399 116 int auto_gc = 0;
0d7566a5 117 char buf[80];
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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 }
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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 }
2c3c4399 138 if (!strcmp(arg, "--auto")) {
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139 auto_gc = 1;
140 continue;
141 }
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142 break;
143 }
144 if (i != argc)
145 usage(builtin_gc_usage);
146
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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
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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}