git/shallow.c
Nguyễn Thái Ngọc Duy 08ea65ad13 shallow: add setup_temporary_shallow()
This function is like setup_alternate_shallow() except that it does
not lock $GIT_DIR/shallow.  It is supposed to be used when a program
generates temporary shallow for use by another program, then throw
the shallow file away.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-08-28 11:51:54 -07:00

223 lines
5.3 KiB
C

#include "cache.h"
#include "commit.h"
#include "tag.h"
#include "pkt-line.h"
static int is_shallow = -1;
static struct stat shallow_stat;
static char *alternate_shallow_file;
void set_alternate_shallow_file(const char *path)
{
if (is_shallow != -1)
die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
free(alternate_shallow_file);
alternate_shallow_file = path ? xstrdup(path) : NULL;
}
int register_shallow(const unsigned char *sha1)
{
struct commit_graft *graft =
xmalloc(sizeof(struct commit_graft));
struct commit *commit = lookup_commit(sha1);
hashcpy(graft->sha1, sha1);
graft->nr_parent = -1;
if (commit && commit->object.parsed)
commit->parents = NULL;
return register_commit_graft(graft, 0);
}
int is_repository_shallow(void)
{
FILE *fp;
char buf[1024];
const char *path = alternate_shallow_file;
if (is_shallow >= 0)
return is_shallow;
if (!path)
path = git_path("shallow");
/*
* fetch-pack sets '--shallow-file ""' as an indicator that no
* shallow file should be used. We could just open it and it
* will likely fail. But let's do an explicit check instead.
*/
if (!*path ||
stat(path, &shallow_stat) ||
(fp = fopen(path, "r")) == NULL) {
is_shallow = 0;
return is_shallow;
}
is_shallow = 1;
while (fgets(buf, sizeof(buf), fp)) {
unsigned char sha1[20];
if (get_sha1_hex(buf, sha1))
die("bad shallow line: %s", buf);
register_shallow(sha1);
}
fclose(fp);
return is_shallow;
}
struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
int shallow_flag, int not_shallow_flag)
{
int i = 0, cur_depth = 0;
struct commit_list *result = NULL;
struct object_array stack = OBJECT_ARRAY_INIT;
struct commit *commit = NULL;
while (commit || i < heads->nr || stack.nr) {
struct commit_list *p;
if (!commit) {
if (i < heads->nr) {
commit = (struct commit *)
deref_tag(heads->objects[i++].item, NULL, 0);
if (!commit || commit->object.type != OBJ_COMMIT) {
commit = NULL;
continue;
}
if (!commit->util)
commit->util = xmalloc(sizeof(int));
*(int *)commit->util = 0;
cur_depth = 0;
} else {
commit = (struct commit *)
stack.objects[--stack.nr].item;
cur_depth = *(int *)commit->util;
}
}
if (parse_commit(commit))
die("invalid commit");
cur_depth++;
if (cur_depth >= depth) {
commit_list_insert(commit, &result);
commit->object.flags |= shallow_flag;
commit = NULL;
continue;
}
commit->object.flags |= not_shallow_flag;
for (p = commit->parents, commit = NULL; p; p = p->next) {
if (!p->item->util) {
int *pointer = xmalloc(sizeof(int));
p->item->util = pointer;
*pointer = cur_depth;
} else {
int *pointer = p->item->util;
if (cur_depth >= *pointer)
continue;
*pointer = cur_depth;
}
if (p->next)
add_object_array(&p->item->object,
NULL, &stack);
else {
commit = p->item;
cur_depth = *(int *)commit->util;
}
}
}
return result;
}
void check_shallow_file_for_update(void)
{
struct stat st;
if (!is_shallow)
return;
else if (is_shallow == -1)
die("BUG: shallow must be initialized by now");
if (stat(git_path("shallow"), &st))
die("shallow file was removed during fetch");
else if (st.st_mtime != shallow_stat.st_mtime
#ifdef USE_NSEC
|| ST_MTIME_NSEC(st) != ST_MTIME_NSEC(shallow_stat)
#endif
)
die("shallow file was changed during fetch");
}
struct write_shallow_data {
struct strbuf *out;
int use_pack_protocol;
int count;
};
static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
{
struct write_shallow_data *data = cb_data;
const char *hex = sha1_to_hex(graft->sha1);
if (graft->nr_parent != -1)
return 0;
data->count++;
if (data->use_pack_protocol)
packet_buf_write(data->out, "shallow %s", hex);
else {
strbuf_addstr(data->out, hex);
strbuf_addch(data->out, '\n');
}
return 0;
}
int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
{
struct write_shallow_data data;
data.out = out;
data.use_pack_protocol = use_pack_protocol;
data.count = 0;
for_each_commit_graft(write_one_shallow, &data);
return data.count;
}
char *setup_temporary_shallow(void)
{
struct strbuf sb = STRBUF_INIT;
int fd;
if (write_shallow_commits(&sb, 0)) {
struct strbuf path = STRBUF_INIT;
strbuf_addstr(&path, git_path("shallow_XXXXXX"));
fd = xmkstemp(path.buf);
if (write_in_full(fd, sb.buf, sb.len) != sb.len)
die_errno("failed to write to %s",
path.buf);
close(fd);
strbuf_release(&sb);
return strbuf_detach(&path, NULL);
}
/*
* is_repository_shallow() sees empty string as "no shallow
* file".
*/
return xstrdup("");
}
void setup_alternate_shallow(struct lock_file *shallow_lock,
const char **alternate_shallow_file)
{
struct strbuf sb = STRBUF_INIT;
int fd;
check_shallow_file_for_update();
fd = hold_lock_file_for_update(shallow_lock, git_path("shallow"),
LOCK_DIE_ON_ERROR);
if (write_shallow_commits(&sb, 0)) {
if (write_in_full(fd, sb.buf, sb.len) != sb.len)
die_errno("failed to write to %s",
shallow_lock->filename);
*alternate_shallow_file = shallow_lock->filename;
} else
/*
* is_repository_shallow() sees empty string as "no
* shallow file".
*/
*alternate_shallow_file = "";
strbuf_release(&sb);
}