/*

* git gc builtin command

*

* Cleanup unreachable files and optimize the repository.

*

* Copyright (c) 2007 James Bowes

*

* Based on git-gc.sh, which is

*

* Copyright (c) 2006 Shawn O. Pearce

*/

#include "builtin.h"

#include "cache.h"

#include "parse-options.h"

#include "run-command.h"

#define FAILED_RUN "failed to run %s"

static const char * const builtin_gc_usage[] = {

"git-gc [options]",

NULL

};

static int pack_refs = 1;

static int aggressive_window = -1;

static int gc_auto_threshold = 6700;

static int gc_auto_pack_limit = 50;

static char *prune_expire = "2.weeks.ago";

#define MAX_ADD 10

static const char *argv_pack_refs[] = {"pack-refs", "--all", "--prune", NULL};

static const char *argv_reflog[] = {"reflog", "expire", "--all", NULL};

static const char *argv_repack[MAX_ADD] = {"repack", "-d", "-l", NULL};

static const char *argv_prune[] = {"prune", "--expire", NULL, NULL};

static const char *argv_rerere[] = {"rerere", "gc", NULL};

static int gc_config(const char *var, const char *value)

{

if (!strcmp(var, "gc.packrefs")) {

if (value && !strcmp(value, "notbare"))

pack_refs = -1;

else

pack_refs = git_config_bool(var, value);

return 0;

}

if (!strcmp(var, "gc.aggressivewindow")) {

aggressive_window = git_config_int(var, value);

return 0;

}

if (!strcmp(var, "gc.auto")) {

gc_auto_threshold = git_config_int(var, value);

return 0;

}

if (!strcmp(var, "gc.autopacklimit")) {

gc_auto_pack_limit = git_config_int(var, value);

return 0;

}

if (!strcmp(var, "gc.pruneexpire")) {

if (!value)

return config_error_nonbool(var);

if (strcmp(value, "now")) {

unsigned long now = approxidate("now");

if (approxidate(value) >= now)

return error("Invalid %s: '%s'", var, value);

}

prune_expire = xstrdup(value);

return 0;

}

return git_default_config(var, value);

}

static void append_option(const char **cmd, const char *opt, int max_length)

{

int i;

for (i = 0; cmd[i]; i++)

;

if (i + 2 >= max_length)

die("Too many options specified");

cmd[i++] = opt;

cmd[i] = NULL;

}

static int too_many_loose_objects(void)

{

/*

* Quickly check if a "gc" is needed, by estimating how

* many loose objects there are. Because SHA-1 is evenly

* distributed, we can check only one and get a reasonable

* estimate.

*/

char path[PATH_MAX];

const char *objdir = get_object_directory();

DIR *dir;

struct dirent *ent;

int auto_threshold;

int num_loose = 0;

int needed = 0;

if (gc_auto_threshold <= 0)

return 0;

if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {

warning("insanely long object directory %.*s", 50, objdir);

return 0;

}

dir = opendir(path);

if (!dir)

return 0;

auto_threshold = (gc_auto_threshold + 255) / 256;

while ((ent = readdir(dir)) != NULL) {

if (strspn(ent->d_name, "0123456789abcdef") != 38 ||

ent->d_name[38] != '\0')

continue;

if (++num_loose > auto_threshold) {

needed = 1;

break;

}

}

closedir(dir);

return needed;

}

static int too_many_packs(void)

{

struct packed_git *p;

int cnt;

if (gc_auto_pack_limit <= 0)

return 0;

prepare_packed_git();

for (cnt = 0, p = packed_git; p; p = p->next) {

char path[PATH_MAX];

size_t len;

int keep;

if (!p->pack_local)

continue;

len = strlen(p->pack_name);

if (PATH_MAX <= len + 1)

continue; /* oops, give up */

memcpy(path, p->pack_name, len-5);

memcpy(path + len - 5, ".keep", 6);

keep = access(p->pack_name, F_OK) && (errno == ENOENT);

if (keep)

continue;

/*

* Perhaps check the size of the pack and count only

* very small ones here?

*/

cnt++;

}

return gc_auto_pack_limit <= cnt;

}

static int run_hook(void)

{

const char *argv[2];

struct child_process hook;

int ret;

argv[0] = git_path("hooks/pre-auto-gc");

argv[1] = NULL;

if (access(argv[0], X_OK) < 0)

return 0;

memset(&hook, 0, sizeof(hook));

hook.argv = argv;

hook.no_stdin = 1;

hook.stdout_to_stderr = 1;

ret = start_command(&hook);

if (ret) {

warning("Could not spawn %s", argv[0]);

return ret;

}

ret = finish_command(&hook);

if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)

warning("%s exited due to uncaught signal", argv[0]);

return ret;

}

static int need_to_gc(void)

{

/*

* Setting gc.auto to 0 or negative can disable the

* automatic gc.

*/

if (gc_auto_threshold <= 0)

return 0;

/*

* If there are too many loose objects, but not too many

* packs, we run "repack -d -l". If there are too many packs,

* we run "repack -A -d -l". Otherwise we tell the caller

* there is no need.

*/

if (too_many_packs())

append_option(argv_repack, "-A", MAX_ADD);

else if (!too_many_loose_objects())

return 0;

if (run_hook())

return 0;

return 1;

}

int cmd_gc(int argc, const char **argv, const char *prefix)

{

int prune = 0;

int aggressive = 0;

int auto_gc = 0;

int quiet = 0;

char buf[80];

struct option builtin_gc_options[] = {

OPT_BOOLEAN(0, "prune", &prune, "prune unreferenced objects"),

OPT_BOOLEAN(0, "aggressive", &aggressive, "be more thorough (increased runtime)"),

OPT_BOOLEAN(0, "auto", &auto_gc, "enable auto-gc mode"),

OPT_BOOLEAN('q', "quiet", &quiet, "suppress progress reports"),

OPT_END()

};

git_config(gc_config);

if (pack_refs < 0)

pack_refs = !is_bare_repository();

argc = parse_options(argc, argv, builtin_gc_options, builtin_gc_usage, 0);

if (argc > 0)

usage_with_options(builtin_gc_usage, builtin_gc_options);

if (aggressive) {

append_option(argv_repack, "-f", MAX_ADD);

if (aggressive_window > 0) {

sprintf(buf, "--window=%d", aggressive_window);

append_option(argv_repack, buf, MAX_ADD);

}

}

if (quiet)

append_option(argv_repack, "-q", MAX_ADD);

if (auto_gc) {

/*

* Auto-gc should be least intrusive as possible.

*/

prune = 0;

if (!need_to_gc())

return 0;

fprintf(stderr, "Auto packing your repository for optimum "

"performance. You may also\n"

"run \"git gc\" manually. See "

"\"git help gc\" for more information.\n");

} else {

/*

* Use safer (for shared repos) "-A" option to

* repack when not pruning. Auto-gc makes its

* own decision.

*/

if (prune)

append_option(argv_repack, "-a", MAX_ADD);

else

append_option(argv_repack, "-A", MAX_ADD);

}

if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))

return error(FAILED_RUN, argv_pack_refs[0]);

if (run_command_v_opt(argv_reflog, RUN_GIT_CMD))

return error(FAILED_RUN, argv_reflog[0]);

if (run_command_v_opt(argv_repack, RUN_GIT_CMD))

return error(FAILED_RUN, argv_repack[0]);

argv_prune[2] = prune_expire;

if (run_command_v_opt(argv_prune, RUN_GIT_CMD))

return error(FAILED_RUN, argv_prune[0]);

if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))

return error(FAILED_RUN, argv_rerere[0]);

if (auto_gc && too_many_loose_objects())

warning("There are too many unreachable loose objects; "

"run 'git prune' to remove them.");

return 0;

}