git/describe.c
Linus Torvalds 885a86abe2 Shrink "struct object" a bit
This shrinks "struct object" by a small amount, by getting rid of the
"struct type *" pointer and replacing it with a 3-bit bitfield instead.

In addition, we merge the bitfields and the "flags" field, which
incidentally should also remove a useless 4-byte padding from the object
when in 64-bit mode.

Now, our "struct object" is still too damn large, but it's now less
obviously bloated, and of the remaining fields, only the "util" (which is
not used by most things) is clearly something that should be eventually
discarded.

This shrinks the "git-rev-list --all" memory use by about 2.5% on the
kernel archive (and, perhaps more importantly, on the larger mozilla
archive). That may not sound like much, but I suspect it's more on a
64-bit platform.

There are other remaining inefficiencies (the parent lists, for example,
probably have horrible malloc overhead), but this was pretty obvious.

Most of the patch is just changing the comparison of the "type" pointer
from one of the constant string pointers to the appropriate new TYPE_xxx
small integer constant.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-17 18:49:18 -07:00

174 lines
3.7 KiB
C

#include "cache.h"
#include "commit.h"
#include "tag.h"
#include "refs.h"
#define SEEN (1u << 0)
static const char describe_usage[] =
"git-describe [--all] [--tags] [--abbrev=<n>] <committish>*";
static int all = 0; /* Default to annotated tags only */
static int tags = 0; /* But allow any tags if --tags is specified */
static int abbrev = DEFAULT_ABBREV;
static int names = 0, allocs = 0;
static struct commit_name {
const struct commit *commit;
int prio; /* annotated tag = 2, tag = 1, head = 0 */
char path[FLEX_ARRAY]; /* more */
} **name_array = NULL;
static struct commit_name *match(struct commit *cmit)
{
int i = names;
struct commit_name **p = name_array;
while (i-- > 0) {
struct commit_name *n = *p++;
if (n->commit == cmit)
return n;
}
return NULL;
}
static void add_to_known_names(const char *path,
const struct commit *commit,
int prio)
{
int idx;
int len = strlen(path)+1;
struct commit_name *name = xmalloc(sizeof(struct commit_name) + len);
name->commit = commit;
name->prio = prio;
memcpy(name->path, path, len);
idx = names;
if (idx >= allocs) {
allocs = (idx + 50) * 3 / 2;
name_array = xrealloc(name_array, allocs*sizeof(*name_array));
}
name_array[idx] = name;
names = ++idx;
}
static int get_name(const char *path, const unsigned char *sha1)
{
struct commit *commit = lookup_commit_reference_gently(sha1, 1);
struct object *object;
int prio;
if (!commit)
return 0;
object = parse_object(sha1);
/* If --all, then any refs are used.
* If --tags, then any tags are used.
* Otherwise only annotated tags are used.
*/
if (!strncmp(path, "refs/tags/", 10)) {
if (object->type == TYPE_TAG)
prio = 2;
else
prio = 1;
}
else
prio = 0;
if (!all) {
if (!prio)
return 0;
if (!tags && prio < 2)
return 0;
}
add_to_known_names(all ? path + 5 : path + 10, commit, prio);
return 0;
}
static int compare_names(const void *_a, const void *_b)
{
struct commit_name *a = *(struct commit_name **)_a;
struct commit_name *b = *(struct commit_name **)_b;
unsigned long a_date = a->commit->date;
unsigned long b_date = b->commit->date;
if (a->prio != b->prio)
return b->prio - a->prio;
return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
}
static void describe(char *arg, int last_one)
{
unsigned char sha1[20];
struct commit *cmit;
struct commit_list *list;
static int initialized = 0;
struct commit_name *n;
if (get_sha1(arg, sha1))
die("Not a valid object name %s", arg);
cmit = lookup_commit_reference(sha1);
if (!cmit)
die("%s is not a valid '%s' object", arg, commit_type);
if (!initialized) {
initialized = 1;
for_each_ref(get_name);
qsort(name_array, names, sizeof(*name_array), compare_names);
}
n = match(cmit);
if (n) {
printf("%s\n", n->path);
return;
}
list = NULL;
commit_list_insert(cmit, &list);
while (list) {
struct commit *c = pop_most_recent_commit(&list, SEEN);
n = match(c);
if (n) {
printf("%s-g%s\n", n->path,
find_unique_abbrev(cmit->object.sha1, abbrev));
if (!last_one)
clear_commit_marks(cmit, SEEN);
return;
}
}
die("cannot describe '%s'", sha1_to_hex(cmit->object.sha1));
}
int main(int argc, char **argv)
{
int i;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
if (*arg != '-')
break;
else if (!strcmp(arg, "--all"))
all = 1;
else if (!strcmp(arg, "--tags"))
tags = 1;
else if (!strncmp(arg, "--abbrev=", 9)) {
abbrev = strtoul(arg + 9, NULL, 10);
if (abbrev < MINIMUM_ABBREV || 40 <= abbrev)
abbrev = DEFAULT_ABBREV;
}
else
usage(describe_usage);
}
if (i == argc)
describe("HEAD", 1);
else
while (i < argc) {
describe(argv[i], (i == argc - 1));
i++;
}
return 0;
}