tvl-depot/third_party/git/abspath.c
Vincent Ambo f4609b896f merge(3p/git): Merge git subtree at v2.29.2
This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb
2020-11-21 19:45:56 +01:00

254 lines
6.4 KiB
C

#include "cache.h"
/*
* Do not use this for inspecting *tracked* content. When path is a
* symlink to a directory, we do not want to say it is a directory when
* dealing with tracked content in the working tree.
*/
int is_directory(const char *path)
{
struct stat st;
return (!stat(path, &st) && S_ISDIR(st.st_mode));
}
/* removes the last path component from 'path' except if 'path' is root */
static void strip_last_component(struct strbuf *path)
{
size_t offset = offset_1st_component(path->buf);
size_t len = path->len;
/* Find start of the last component */
while (offset < len && !is_dir_sep(path->buf[len - 1]))
len--;
/* Skip sequences of multiple path-separators */
while (offset < len && is_dir_sep(path->buf[len - 1]))
len--;
strbuf_setlen(path, len);
}
/* get (and remove) the next component in 'remaining' and place it in 'next' */
static void get_next_component(struct strbuf *next, struct strbuf *remaining)
{
char *start = NULL;
char *end = NULL;
strbuf_reset(next);
/* look for the next component */
/* Skip sequences of multiple path-separators */
for (start = remaining->buf; is_dir_sep(*start); start++)
; /* nothing */
/* Find end of the path component */
for (end = start; *end && !is_dir_sep(*end); end++)
; /* nothing */
strbuf_add(next, start, end - start);
/* remove the component from 'remaining' */
strbuf_remove(remaining, 0, end - remaining->buf);
}
/* copies root part from remaining to resolved, canonicalizing it on the way */
static void get_root_part(struct strbuf *resolved, struct strbuf *remaining)
{
int offset = offset_1st_component(remaining->buf);
strbuf_reset(resolved);
strbuf_add(resolved, remaining->buf, offset);
#ifdef GIT_WINDOWS_NATIVE
convert_slashes(resolved->buf);
#endif
strbuf_remove(remaining, 0, offset);
}
/* We allow "recursive" symbolic links. Only within reason, though. */
#ifndef MAXSYMLINKS
#define MAXSYMLINKS 32
#endif
/*
* Return the real path (i.e., absolute path, with symlinks resolved
* and extra slashes removed) equivalent to the specified path. (If
* you want an absolute path but don't mind links, use
* absolute_path().) Places the resolved realpath in the provided strbuf.
*
* The directory part of path (i.e., everything up to the last
* dir_sep) must denote a valid, existing directory, but the last
* component need not exist. If die_on_error is set, then die with an
* informative error message if there is a problem. Otherwise, return
* NULL on errors (without generating any output).
*/
char *strbuf_realpath(struct strbuf *resolved, const char *path,
int die_on_error)
{
struct strbuf remaining = STRBUF_INIT;
struct strbuf next = STRBUF_INIT;
struct strbuf symlink = STRBUF_INIT;
char *retval = NULL;
int num_symlinks = 0;
struct stat st;
if (!*path) {
if (die_on_error)
die("The empty string is not a valid path");
else
goto error_out;
}
strbuf_addstr(&remaining, path);
get_root_part(resolved, &remaining);
if (!resolved->len) {
/* relative path; can use CWD as the initial resolved path */
if (strbuf_getcwd(resolved)) {
if (die_on_error)
die_errno("unable to get current working directory");
else
goto error_out;
}
}
/* Iterate over the remaining path components */
while (remaining.len > 0) {
get_next_component(&next, &remaining);
if (next.len == 0) {
continue; /* empty component */
} else if (next.len == 1 && !strcmp(next.buf, ".")) {
continue; /* '.' component */
} else if (next.len == 2 && !strcmp(next.buf, "..")) {
/* '..' component; strip the last path component */
strip_last_component(resolved);
continue;
}
/* append the next component and resolve resultant path */
if (!is_dir_sep(resolved->buf[resolved->len - 1]))
strbuf_addch(resolved, '/');
strbuf_addbuf(resolved, &next);
if (lstat(resolved->buf, &st)) {
/* error out unless this was the last component */
if (errno != ENOENT || remaining.len) {
if (die_on_error)
die_errno("Invalid path '%s'",
resolved->buf);
else
goto error_out;
}
} else if (S_ISLNK(st.st_mode)) {
ssize_t len;
strbuf_reset(&symlink);
if (num_symlinks++ > MAXSYMLINKS) {
errno = ELOOP;
if (die_on_error)
die("More than %d nested symlinks "
"on path '%s'", MAXSYMLINKS, path);
else
goto error_out;
}
len = strbuf_readlink(&symlink, resolved->buf,
st.st_size);
if (len < 0) {
if (die_on_error)
die_errno("Invalid symlink '%s'",
resolved->buf);
else
goto error_out;
}
if (is_absolute_path(symlink.buf)) {
/* absolute symlink; set resolved to root */
get_root_part(resolved, &symlink);
} else {
/*
* relative symlink
* strip off the last component since it will
* be replaced with the contents of the symlink
*/
strip_last_component(resolved);
}
/*
* if there are still remaining components to resolve
* then append them to symlink
*/
if (remaining.len) {
strbuf_addch(&symlink, '/');
strbuf_addbuf(&symlink, &remaining);
}
/*
* use the symlink as the remaining components that
* need to be resolved
*/
strbuf_swap(&symlink, &remaining);
}
}
retval = resolved->buf;
error_out:
strbuf_release(&remaining);
strbuf_release(&next);
strbuf_release(&symlink);
if (!retval)
strbuf_reset(resolved);
return retval;
}
char *real_pathdup(const char *path, int die_on_error)
{
struct strbuf realpath = STRBUF_INIT;
char *retval = NULL;
if (strbuf_realpath(&realpath, path, die_on_error))
retval = strbuf_detach(&realpath, NULL);
strbuf_release(&realpath);
return retval;
}
/*
* Use this to get an absolute path from a relative one. If you want
* to resolve links, you should use strbuf_realpath.
*/
const char *absolute_path(const char *path)
{
static struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
strbuf_add_absolute_path(&sb, path);
return sb.buf;
}
char *absolute_pathdup(const char *path)
{
struct strbuf sb = STRBUF_INIT;
strbuf_add_absolute_path(&sb, path);
return strbuf_detach(&sb, NULL);
}
char *prefix_filename(const char *pfx, const char *arg)
{
struct strbuf path = STRBUF_INIT;
size_t pfx_len = pfx ? strlen(pfx) : 0;
if (!pfx_len)
; /* nothing to prefix */
else if (is_absolute_path(arg))
pfx_len = 0;
else
strbuf_add(&path, pfx, pfx_len);
strbuf_addstr(&path, arg);
#ifdef GIT_WINDOWS_NATIVE
convert_slashes(path.buf + pfx_len);
#endif
return strbuf_detach(&path, NULL);
}