git/setup.c
Junio C Hamano 8098a178b2 Add git-symbolic-ref
This adds the counterpart of git-update-ref that lets you read
and create "symbolic refs".  By default it uses a symbolic link
to represent ".git/HEAD -> refs/heads/master", but it can be compiled
to use the textfile symbolic ref.

The places that did 'readlink .git/HEAD' and 'ln -s refs/heads/blah
.git/HEAD' have been converted to use new git-symbolic-ref command, so
that they can deal with either implementation.

Signed-off-by: Junio C Hamano <junio@twinsun.com>
2005-10-01 23:19:33 -07:00

130 lines
2.5 KiB
C

#include "cache.h"
const char *prefix_path(const char *prefix, int len, const char *path)
{
const char *orig = path;
for (;;) {
char c;
if (*path != '.')
break;
c = path[1];
/* "." */
if (!c) {
path++;
break;
}
/* "./" */
if (c == '/') {
path += 2;
continue;
}
if (c != '.')
break;
c = path[2];
if (!c)
path += 2;
else if (c == '/')
path += 3;
else
break;
/* ".." and "../" */
/* Remove last component of the prefix */
do {
if (!len)
die("'%s' is outside repository", orig);
len--;
} while (len && prefix[len-1] != '/');
continue;
}
if (len) {
int speclen = strlen(path);
char *n = xmalloc(speclen + len + 1);
memcpy(n, prefix, len);
memcpy(n + len, path, speclen+1);
path = n;
}
return path;
}
const char **get_pathspec(const char *prefix, const char **pathspec)
{
const char *entry = *pathspec;
const char **p;
int prefixlen;
if (!prefix && !entry)
return NULL;
if (!entry) {
static const char *spec[2];
spec[0] = prefix;
spec[1] = NULL;
return spec;
}
/* Otherwise we have to re-write the entries.. */
p = pathspec;
prefixlen = prefix ? strlen(prefix) : 0;
do {
*p = prefix_path(prefix, prefixlen, entry);
} while ((entry = *++p) != NULL);
return (const char **) pathspec;
}
/*
* Test it it looks like we're at the top
* level git directory. We want to see a
*
* - either a .git/objects/ directory _or_ the proper
* GIT_OBJECT_DIRECTORY environment variable
* - a refs/ directory under ".git"
* - either a HEAD symlink or a HEAD file that is formatted as
* a proper "ref:".
*/
static int is_toplevel_directory(void)
{
if (access(".git/refs/", X_OK) ||
access(getenv(DB_ENVIRONMENT) ?
getenv(DB_ENVIRONMENT) : ".git/objects/", X_OK) ||
validate_symref(".git/HEAD"))
return 0;
return 1;
}
const char *setup_git_directory(void)
{
static char cwd[PATH_MAX+1];
int len, offset;
/*
* If GIT_DIR is set explicitly, we're not going
* to do any discovery
*/
if (getenv(GIT_DIR_ENVIRONMENT))
return NULL;
if (!getcwd(cwd, sizeof(cwd)) || cwd[0] != '/')
die("Unable to read current working directory");
offset = len = strlen(cwd);
for (;;) {
if (is_toplevel_directory())
break;
chdir("..");
do {
if (!offset)
die("Not a git repository");
} while (cwd[--offset] != '/');
}
if (offset == len)
return NULL;
/* Make "offset" point to past the '/', and add a '/' at the end */
offset++;
cwd[len++] = '/';
cwd[len] = 0;
return cwd + offset;
}