[PATCH] Allow reading "symbolic refs" that point to other refs

This extends the ref reading to understand a "symbolic ref": a ref file
that starts with "ref: " and points to another ref file, and thus
introduces the notion of ref aliases.

This is in preparation of allowing HEAD to eventually not be a symlink,
but one of these symbolic refs instead.

[jc: Linus originally required the prefix to be "ref: " five bytes
 and nothing else, but I changed it to allow and strip any number of
 leading whitespaces to match what update-ref.c does.]

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Linus Torvalds 2005-09-25 09:59:37 -07:00 коммит произвёл Junio C Hamano
Родитель 9b143c6e15
Коммит ca8db1424d
3 изменённых файлов: 42 добавлений и 49 удалений

Просмотреть файл

@ -229,6 +229,7 @@ extern int has_pack_index(const unsigned char *sha1);
extern int get_sha1(const char *str, unsigned char *sha1);
extern int get_sha1_hex(const char *hex, unsigned char *sha1);
extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */
extern int read_ref(const char *filename, unsigned char *sha1);
/* General helper functions */
extern void usage(const char *err) NORETURN;

73
refs.c
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@ -2,17 +2,43 @@
#include "cache.h"
#include <errno.h>
#include <ctype.h>
static int read_ref(const char *refname, unsigned char *sha1)
/* We allow "recursive" symbolic refs. Only within reason, though */
#define MAXDEPTH 5
int read_ref(const char *filename, unsigned char *sha1)
{
int ret = -1;
int fd = open(git_path("%s", refname), O_RDONLY);
int depth = 0;
int ret = -1, fd;
while ((fd = open(filename, O_RDONLY)) >= 0) {
char buffer[256];
int len = read(fd, buffer, sizeof(buffer)-1);
if (fd >= 0) {
char buffer[60];
if (read(fd, buffer, sizeof(buffer)) >= 40)
ret = get_sha1_hex(buffer, sha1);
close(fd);
if (len < 0)
break;
buffer[len] = 0;
while (len && isspace(buffer[len-1]))
buffer[--len] = 0;
if (!strncmp(buffer, "ref:", 4)) {
char *buf;
if (depth > MAXDEPTH)
break;
depth++;
buf = buffer + 4;
len -= 4;
while (len && isspace(*buf))
buf++, len--;
filename = git_path("%.*s", len, buf);
continue;
}
if (len >= 40)
ret = get_sha1_hex(buffer, sha1);
break;
}
return ret;
}
@ -54,7 +80,7 @@ static int do_for_each_ref(const char *base, int (*fn)(const char *path, const u
break;
continue;
}
if (read_ref(path, sha1) < 0)
if (read_ref(git_path("%s", path), sha1) < 0)
continue;
if (!has_sha1_file(sha1))
continue;
@ -71,7 +97,7 @@ static int do_for_each_ref(const char *base, int (*fn)(const char *path, const u
int head_ref(int (*fn)(const char *path, const unsigned char *sha1))
{
unsigned char sha1[20];
if (!read_ref("HEAD", sha1))
if (!read_ref(git_path("HEAD"), sha1))
return fn("HEAD", sha1);
return 0;
}
@ -101,33 +127,14 @@ static char *ref_lock_file_name(const char *ref)
return ret;
}
static int read_ref_file(const char *filename, unsigned char *sha1) {
int fd = open(filename, O_RDONLY);
char hex[41];
if (fd < 0) {
return error("Couldn't open %s\n", filename);
}
if ((read(fd, hex, 41) < 41) ||
(hex[40] != '\n') ||
get_sha1_hex(hex, sha1)) {
error("Couldn't read a hash from %s\n", filename);
close(fd);
return -1;
}
close(fd);
return 0;
}
int get_ref_sha1(const char *ref, unsigned char *sha1)
{
char *filename;
int retval;
const char *filename;
if (check_ref_format(ref))
return -1;
filename = ref_file_name(ref);
retval = read_ref_file(filename, sha1);
free(filename);
return retval;
filename = git_path("refs/%s", ref);
return read_ref(filename, sha1);
}
static int lock_ref_file(const char *filename, const char *lock_filename,
@ -140,7 +147,7 @@ static int lock_ref_file(const char *filename, const char *lock_filename,
return error("Couldn't open lock file for %s: %s",
filename, strerror(errno));
}
retval = read_ref_file(filename, current_sha1);
retval = read_ref(filename, current_sha1);
if (old_sha1) {
if (retval) {
close(fd);

Просмотреть файл

@ -119,21 +119,6 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1)
return -1;
}
static int get_sha1_file(const char *path, unsigned char *result)
{
char buffer[60];
int fd = open(path, O_RDONLY);
int len;
if (fd < 0)
return -1;
len = read(fd, buffer, sizeof(buffer));
close(fd);
if (len < 40)
return -1;
return get_sha1_hex(buffer, result);
}
static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
{
static const char *prefix[] = {
@ -150,7 +135,7 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
for (p = prefix; *p; p++) {
char *pathname = git_path("%s/%.*s", *p, len, str);
if (!get_sha1_file(pathname, sha1))
if (!read_ref(pathname, sha1))
return 0;
}