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git/entry.c
Junio C Hamano af2a651d2e checkout_entry(): clarify the use of topath[] parameter
The said function has this signature:

	extern int checkout_entry(struct cache_entry *ce,
				  const struct checkout *state,
				  char *topath);

At first glance, it might appear that the caller of checkout_entry()
can specify to which path the contents are written out by the last
parameter, and it is tempting to add "const" in front of its type.

In reality, however, topath[] is to point at a buffer to store the
temporary path generated by the callchain originating from this
function, and the temporary path is always short, much shorter than
the buffer prepared by its only caller in builtin/checkout-index.c.

Document the code a bit to clarify so that future callers know how
to use the function better.

Noticed-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-10-24 14:59:39 -07:00

291 lines
7.3 KiB
C

#include "cache.h"
#include "blob.h"
#include "dir.h"
#include "streaming.h"
static void create_directories(const char *path, int path_len,
const struct checkout *state)
{
char *buf = xmalloc(path_len + 1);
int len = 0;
while (len < path_len) {
do {
buf[len] = path[len];
len++;
} while (len < path_len && path[len] != '/');
if (len >= path_len)
break;
buf[len] = 0;
/*
* For 'checkout-index --prefix=<dir>', <dir> is
* allowed to be a symlink to an existing directory,
* and we set 'state->base_dir_len' below, such that
* we test the path components of the prefix with the
* stat() function instead of the lstat() function.
*/
if (has_dirs_only_path(buf, len, state->base_dir_len))
continue; /* ok, it is already a directory. */
/*
* If this mkdir() would fail, it could be that there
* is already a symlink or something else exists
* there, therefore we then try to unlink it and try
* one more time to create the directory.
*/
if (mkdir(buf, 0777)) {
if (errno == EEXIST && state->force &&
!unlink_or_warn(buf) && !mkdir(buf, 0777))
continue;
die_errno("cannot create directory at '%s'", buf);
}
}
free(buf);
}
static void remove_subtree(const char *path)
{
DIR *dir = opendir(path);
struct dirent *de;
char pathbuf[PATH_MAX];
char *name;
if (!dir)
die_errno("cannot opendir '%s'", path);
strcpy(pathbuf, path);
name = pathbuf + strlen(path);
*name++ = '/';
while ((de = readdir(dir)) != NULL) {
struct stat st;
if (is_dot_or_dotdot(de->d_name))
continue;
strcpy(name, de->d_name);
if (lstat(pathbuf, &st))
die_errno("cannot lstat '%s'", pathbuf);
if (S_ISDIR(st.st_mode))
remove_subtree(pathbuf);
else if (unlink(pathbuf))
die_errno("cannot unlink '%s'", pathbuf);
}
closedir(dir);
if (rmdir(path))
die_errno("cannot rmdir '%s'", path);
}
static int create_file(const char *path, unsigned int mode)
{
mode = (mode & 0100) ? 0777 : 0666;
return open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
}
static void *read_blob_entry(const struct cache_entry *ce, unsigned long *size)
{
enum object_type type;
void *new = read_sha1_file(ce->sha1, &type, size);
if (new) {
if (type == OBJ_BLOB)
return new;
free(new);
}
return NULL;
}
static int open_output_fd(char *path, const struct cache_entry *ce, int to_tempfile)
{
int symlink = (ce->ce_mode & S_IFMT) != S_IFREG;
if (to_tempfile) {
strcpy(path, symlink
? ".merge_link_XXXXXX" : ".merge_file_XXXXXX");
return mkstemp(path);
} else {
return create_file(path, !symlink ? ce->ce_mode : 0666);
}
}
static int fstat_output(int fd, const struct checkout *state, struct stat *st)
{
/* use fstat() only when path == ce->name */
if (fstat_is_reliable() &&
state->refresh_cache && !state->base_dir_len) {
fstat(fd, st);
return 1;
}
return 0;
}
static int streaming_write_entry(const struct cache_entry *ce, char *path,
struct stream_filter *filter,
const struct checkout *state, int to_tempfile,
int *fstat_done, struct stat *statbuf)
{
int result = 0;
int fd;
fd = open_output_fd(path, ce, to_tempfile);
if (fd < 0)
return -1;
result |= stream_blob_to_fd(fd, ce->sha1, filter, 1);
*fstat_done = fstat_output(fd, state, statbuf);
result |= close(fd);
if (result)
unlink(path);
return result;
}
static int write_entry(struct cache_entry *ce,
char *path, const struct checkout *state, int to_tempfile)
{
unsigned int ce_mode_s_ifmt = ce->ce_mode & S_IFMT;
int fd, ret, fstat_done = 0;
char *new;
struct strbuf buf = STRBUF_INIT;
unsigned long size;
size_t wrote, newsize = 0;
struct stat st;
if (ce_mode_s_ifmt == S_IFREG) {
struct stream_filter *filter = get_stream_filter(ce->name, ce->sha1);
if (filter &&
!streaming_write_entry(ce, path, filter,
state, to_tempfile,
&fstat_done, &st))
goto finish;
}
switch (ce_mode_s_ifmt) {
case S_IFREG:
case S_IFLNK:
new = read_blob_entry(ce, &size);
if (!new)
return error("unable to read sha1 file of %s (%s)",
path, sha1_to_hex(ce->sha1));
if (ce_mode_s_ifmt == S_IFLNK && has_symlinks && !to_tempfile) {
ret = symlink(new, path);
free(new);
if (ret)
return error("unable to create symlink %s (%s)",
path, strerror(errno));
break;
}
/*
* Convert from git internal format to working tree format
*/
if (ce_mode_s_ifmt == S_IFREG &&
convert_to_working_tree(ce->name, new, size, &buf)) {
free(new);
new = strbuf_detach(&buf, &newsize);
size = newsize;
}
fd = open_output_fd(path, ce, to_tempfile);
if (fd < 0) {
free(new);
return error("unable to create file %s (%s)",
path, strerror(errno));
}
wrote = write_in_full(fd, new, size);
if (!to_tempfile)
fstat_done = fstat_output(fd, state, &st);
close(fd);
free(new);
if (wrote != size)
return error("unable to write file %s", path);
break;
case S_IFGITLINK:
if (to_tempfile)
return error("cannot create temporary submodule %s", path);
if (mkdir(path, 0777) < 0)
return error("cannot create submodule directory %s", path);
break;
default:
return error("unknown file mode for %s in index", path);
}
finish:
if (state->refresh_cache) {
if (!fstat_done)
lstat(ce->name, &st);
fill_stat_cache_info(ce, &st);
}
return 0;
}
/*
* This is like 'lstat()', except it refuses to follow symlinks
* in the path, after skipping "skiplen".
*/
static int check_path(const char *path, int len, struct stat *st, int skiplen)
{
const char *slash = path + len;
while (path < slash && *slash != '/')
slash--;
if (!has_dirs_only_path(path, slash - path, skiplen)) {
errno = ENOENT;
return -1;
}
return lstat(path, st);
}
/*
* Write the contents from ce out to the working tree.
*
* When topath[] is not NULL, instead of writing to the working tree
* file named by ce, a temporary file is created by this function and
* its name is returned in topath[], which must be able to hold at
* least TEMPORARY_FILENAME_LENGTH bytes long.
*/
int checkout_entry(struct cache_entry *ce,
const struct checkout *state, char *topath)
{
static struct strbuf path_buf = STRBUF_INIT;
char *path;
struct stat st;
int len;
if (topath)
return write_entry(ce, topath, state, 1);
strbuf_reset(&path_buf);
strbuf_add(&path_buf, state->base_dir, state->base_dir_len);
strbuf_add(&path_buf, ce->name, ce_namelen(ce));
path = path_buf.buf;
len = path_buf.len;
if (!check_path(path, len, &st, state->base_dir_len)) {
unsigned changed = ce_match_stat(ce, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
if (!changed)
return 0;
if (!state->force) {
if (!state->quiet)
fprintf(stderr, "%s already exists, no checkout\n", path);
return -1;
}
/*
* We unlink the old file, to get the new one with the
* right permissions (including umask, which is nasty
* to emulate by hand - much easier to let the system
* just do the right thing)
*/
if (S_ISDIR(st.st_mode)) {
/* If it is a gitlink, leave it alone! */
if (S_ISGITLINK(ce->ce_mode))
return 0;
if (!state->force)
return error("%s is a directory", path);
remove_subtree(path);
} else if (unlink(path))
return error("unable to unlink old '%s' (%s)", path, strerror(errno));
} else if (state->not_new)
return 0;
create_directories(path, len, state);
return write_entry(ce, path, state, 0);
}