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git/server-info.c

368 lines
7.5 KiB

#include "cache.h"
#include "dir.h"
#include "repository.h"
#include "refs.h"
#include "object.h"
#include "commit.h"
#include "tag.h"
#include "packfile.h"
#include "object-store.h"
#include "strbuf.h"
struct update_info_ctx {
FILE *cur_fp;
FILE *old_fp; /* becomes NULL if it differs from cur_fp */
struct strbuf cur_sb;
struct strbuf old_sb;
};
static void uic_mark_stale(struct update_info_ctx *uic)
{
fclose(uic->old_fp);
uic->old_fp = NULL;
}
static int uic_is_stale(const struct update_info_ctx *uic)
{
return uic->old_fp == NULL;
}
__attribute__((format (printf, 2, 3)))
static int uic_printf(struct update_info_ctx *uic, const char *fmt, ...)
{
va_list ap;
int ret = -1;
va_start(ap, fmt);
if (uic_is_stale(uic)) {
ret = vfprintf(uic->cur_fp, fmt, ap);
} else {
ssize_t r;
struct strbuf *cur = &uic->cur_sb;
struct strbuf *old = &uic->old_sb;
strbuf_reset(cur);
strbuf_vinsertf(cur, 0, fmt, ap);
strbuf_reset(old);
strbuf_grow(old, cur->len);
r = fread(old->buf, 1, cur->len, uic->old_fp);
if (r != cur->len || memcmp(old->buf, cur->buf, r))
uic_mark_stale(uic);
if (fwrite(cur->buf, 1, cur->len, uic->cur_fp) == cur->len)
ret = 0;
}
va_end(ap);
return ret;
}
/*
* Create the file "path" by writing to a temporary file and renaming
* it into place. The contents of the file come from "generate", which
* should return non-zero if it encounters an error.
*/
static int update_info_file(char *path,
int (*generate)(struct update_info_ctx *),
int force)
{
char *tmp = mkpathdup("%s_XXXXXX", path);
int ret = -1;
int fd = -1;
FILE *to_close;
struct update_info_ctx uic = {
.cur_fp = NULL,
.old_fp = NULL,
.cur_sb = STRBUF_INIT,
.old_sb = STRBUF_INIT
};
safe_create_leading_directories(path);
fd = git_mkstemp_mode(tmp, 0666);
if (fd < 0)
goto out;
to_close = uic.cur_fp = fdopen(fd, "w");
if (!uic.cur_fp)
goto out;
fd = -1;
/* no problem on ENOENT and old_fp == NULL, it's stale, now */
if (!force)
uic.old_fp = fopen_or_warn(path, "r");
/*
* uic_printf will compare incremental comparison against old_fp
* and mark uic as stale if needed
*/
ret = generate(&uic);
if (ret)
goto out;
/* new file may be shorter than the old one, check here */
if (!uic_is_stale(&uic)) {
struct stat st;
long new_len = ftell(uic.cur_fp);
int old_fd = fileno(uic.old_fp);
if (new_len < 0) {
ret = -1;
goto out;
}
if (fstat(old_fd, &st) || (st.st_size != (size_t)new_len))
uic_mark_stale(&uic);
}
uic.cur_fp = NULL;
if (fclose(to_close))
goto out;
if (uic_is_stale(&uic)) {
if (adjust_shared_perm(tmp) < 0)
goto out;
if (rename(tmp, path) < 0)
goto out;
} else {
unlink(tmp);
}
ret = 0;
out:
if (ret) {
error_errno("unable to update %s", path);
if (uic.cur_fp)
fclose(uic.cur_fp);
else if (fd >= 0)
close(fd);
unlink(tmp);
}
free(tmp);
if (uic.old_fp)
fclose(uic.old_fp);
strbuf_release(&uic.old_sb);
strbuf_release(&uic.cur_sb);
return ret;
}
static int add_info_ref(const char *path, const struct object_id *oid,
int flag, void *cb_data)
{
struct update_info_ctx *uic = cb_data;
struct object *o = parse_object(the_repository, oid);
if (!o)
return -1;
if (uic_printf(uic, "%s %s\n", oid_to_hex(oid), path) < 0)
return -1;
if (o->type == OBJ_TAG) {
o = deref_tag(the_repository, o, path, 0);
if (o)
if (uic_printf(uic, "%s %s^{}\n",
oid_to_hex(&o->oid), path) < 0)
return -1;
}
return 0;
}
static int generate_info_refs(struct update_info_ctx *uic)
{
return for_each_ref(add_info_ref, uic);
}
static int update_info_refs(int force)
{
char *path = git_pathdup("info/refs");
int ret = update_info_file(path, generate_info_refs, force);
free(path);
return ret;
}
/* packs */
static struct pack_info {
struct packed_git *p;
int old_num;
int new_num;
} **info;
static int num_pack;
static struct pack_info *find_pack_by_name(const char *name)
{
int i;
for (i = 0; i < num_pack; i++) {
struct packed_git *p = info[i]->p;
if (!strcmp(pack_basename(p), name))
return info[i];
}
return NULL;
}
/* Returns non-zero when we detect that the info in the
* old file is useless.
*/
static int parse_pack_def(const char *packname, int old_cnt)
{
struct pack_info *i = find_pack_by_name(packname);
if (i) {
i->old_num = old_cnt;
return 0;
}
else {
/* The file describes a pack that is no longer here */
return 1;
}
}
/* Returns non-zero when we detect that the info in the
* old file is useless.
*/
static int read_pack_info_file(const char *infofile)
{
FILE *fp;
struct strbuf line = STRBUF_INIT;
int old_cnt = 0;
int stale = 1;
fp = fopen_or_warn(infofile, "r");
if (!fp)
return 1; /* nonexistent is not an error. */
while (strbuf_getline(&line, fp) != EOF) {
const char *arg;
if (!line.len)
continue;
if (skip_prefix(line.buf, "P ", &arg)) {
/* P name */
if (parse_pack_def(arg, old_cnt++))
goto out_stale;
} else if (line.buf[0] == 'D') {
/* we used to emit D but that was misguided. */
goto out_stale;
} else if (line.buf[0] == 'T') {
/* we used to emit T but nobody uses it. */
goto out_stale;
} else {
error("unrecognized: %s", line.buf);
}
}
stale = 0;
out_stale:
strbuf_release(&line);
fclose(fp);
return stale;
}
static int compare_info(const void *a_, const void *b_)
{
struct pack_info *const *a = a_;
struct pack_info *const *b = b_;
if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
/* Keep the order in the original */
return (*a)->old_num - (*b)->old_num;
else if (0 <= (*a)->old_num)
/* Only A existed in the original so B is obviously newer */
return -1;
else if (0 <= (*b)->old_num)
/* The other way around. */
return 1;
/* then it does not matter but at least keep the comparison stable */
if ((*a)->p == (*b)->p)
return 0;
else if ((*a)->p < (*b)->p)
return -1;
else
return 1;
}
static void init_pack_info(const char *infofile, int force)
{
struct packed_git *p;
int stale;
int i;
size_t alloc = 0;
for (p = get_all_packs(the_repository); p; p = p->next) {
/* we ignore things on alternate path since they are
* not available to the pullers in general.
*/
if (!p->pack_local || !file_exists(p->pack_name))
continue;
i = num_pack++;
ALLOC_GROW(info, num_pack, alloc);
CALLOC_ARRAY(info[i], 1);
info[i]->p = p;
info[i]->old_num = -1;
}
if (infofile && !force)
stale = read_pack_info_file(infofile);
else
stale = 1;
for (i = 0; i < num_pack; i++)
if (stale)
info[i]->old_num = -1;
/* renumber them */
QSORT(info, num_pack, compare_info);
for (i = 0; i < num_pack; i++)
info[i]->new_num = i;
}
static void free_pack_info(void)
{
int i;
for (i = 0; i < num_pack; i++)
free(info[i]);
free(info);
}
static int write_pack_info_file(struct update_info_ctx *uic)
{
int i;
for (i = 0; i < num_pack; i++) {
if (uic_printf(uic, "P %s\n", pack_basename(info[i]->p)) < 0)
return -1;
}
if (uic_printf(uic, "\n") < 0)
return -1;
return 0;
}
static int update_info_packs(int force)
{
char *infofile = mkpathdup("%s/info/packs", get_object_directory());
int ret;
init_pack_info(infofile, force);
ret = update_info_file(infofile, write_pack_info_file, force);
free_pack_info();
free(infofile);
return ret;
}
/* public */
int update_server_info(int force)
{
/* We would add more dumb-server support files later,
* including index of available pack files and their
* intended audiences.
*/
int errs = 0;
errs = errs | update_info_refs(force);
errs = errs | update_info_packs(force);
/* remove leftover rev-cache file if there is any */
unlink_or_warn(git_path("info/rev-cache"));
return errs;
}