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![Kjetil Barvik](/assets/img/avatar_default.png)
The create_directories() function in entry.c currently calls stat() or lstat() for each path component of the pathname 'path' each and every time. For the 'git checkout' command, this function is called on each file for which we must do an update (ce->ce_flags & CE_UPDATE), so we get lots and lots of calls. To fix this, we make a new wrapper to the lstat_cache() function, and call the wrapper function instead of the calls to the stat() or the lstat() functions. Since the paths given to the create_directories() function, is sorted alphabetically, the new wrapper would be very cache effective in this situation. To support it we must update the lstat_cache() function to be able to say that "please test the complete length of 'name'", and also to give it the length of a prefix, where the cache should use the stat() function instead of the lstat() function to test each path component. Thanks to Junio C Hamano, Linus Torvalds and Rene Scharfe for valuable comments to this patch! Signed-off-by: Kjetil Barvik <barvik@broadpark.no> Signed-off-by: Junio C Hamano <gitster@pobox.com>
225 lines
5.8 KiB
C
225 lines
5.8 KiB
C
#include "cache.h"
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#include "blob.h"
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static void create_directories(const char *path, const struct checkout *state)
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{
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int len = strlen(path);
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char *buf = xmalloc(len + 1);
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const char *slash = path;
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while ((slash = strchr(slash+1, '/')) != NULL) {
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len = slash - path;
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memcpy(buf, path, len);
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buf[len] = 0;
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/*
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* For 'checkout-index --prefix=<dir>', <dir> is
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* allowed to be a symlink to an existing directory,
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* and we set 'state->base_dir_len' below, such that
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* we test the path components of the prefix with the
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* stat() function instead of the lstat() function.
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*/
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if (has_dirs_only_path(len, buf, state->base_dir_len))
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continue; /* ok, it is already a directory. */
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/*
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* If this mkdir() would fail, it could be that there
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* is already a symlink or something else exists
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* there, therefore we then try to unlink it and try
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* one more time to create the directory.
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*/
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if (mkdir(buf, 0777)) {
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if (errno == EEXIST && state->force &&
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!unlink(buf) && !mkdir(buf, 0777))
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continue;
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die("cannot create directory at %s", buf);
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}
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}
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free(buf);
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}
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static void remove_subtree(const char *path)
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{
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DIR *dir = opendir(path);
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struct dirent *de;
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char pathbuf[PATH_MAX];
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char *name;
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if (!dir)
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die("cannot opendir %s (%s)", path, strerror(errno));
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strcpy(pathbuf, path);
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name = pathbuf + strlen(path);
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*name++ = '/';
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while ((de = readdir(dir)) != NULL) {
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struct stat st;
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if ((de->d_name[0] == '.') &&
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((de->d_name[1] == 0) ||
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((de->d_name[1] == '.') && de->d_name[2] == 0)))
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continue;
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strcpy(name, de->d_name);
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if (lstat(pathbuf, &st))
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die("cannot lstat %s (%s)", pathbuf, strerror(errno));
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if (S_ISDIR(st.st_mode))
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remove_subtree(pathbuf);
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else if (unlink(pathbuf))
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die("cannot unlink %s (%s)", pathbuf, strerror(errno));
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}
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closedir(dir);
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if (rmdir(path))
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die("cannot rmdir %s (%s)", path, strerror(errno));
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}
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static int create_file(const char *path, unsigned int mode)
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{
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mode = (mode & 0100) ? 0777 : 0666;
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return open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
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}
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static void *read_blob_entry(struct cache_entry *ce, const char *path, unsigned long *size)
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{
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enum object_type type;
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void *new = read_sha1_file(ce->sha1, &type, size);
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if (new) {
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if (type == OBJ_BLOB)
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return new;
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free(new);
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}
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return NULL;
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}
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static int write_entry(struct cache_entry *ce, char *path, const struct checkout *state, int to_tempfile)
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{
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int fd;
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long wrote;
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switch (ce->ce_mode & S_IFMT) {
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char *new;
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struct strbuf buf;
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unsigned long size;
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case S_IFREG:
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new = read_blob_entry(ce, path, &size);
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if (!new)
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return error("git checkout-index: unable to read sha1 file of %s (%s)",
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path, sha1_to_hex(ce->sha1));
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/*
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* Convert from git internal format to working tree format
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*/
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strbuf_init(&buf, 0);
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if (convert_to_working_tree(ce->name, new, size, &buf)) {
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size_t newsize = 0;
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free(new);
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new = strbuf_detach(&buf, &newsize);
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size = newsize;
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}
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if (to_tempfile) {
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strcpy(path, ".merge_file_XXXXXX");
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fd = mkstemp(path);
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} else
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fd = create_file(path, ce->ce_mode);
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if (fd < 0) {
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free(new);
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return error("git checkout-index: unable to create file %s (%s)",
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path, strerror(errno));
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}
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wrote = write_in_full(fd, new, size);
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close(fd);
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free(new);
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if (wrote != size)
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return error("git checkout-index: unable to write file %s", path);
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break;
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case S_IFLNK:
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new = read_blob_entry(ce, path, &size);
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if (!new)
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return error("git checkout-index: unable to read sha1 file of %s (%s)",
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path, sha1_to_hex(ce->sha1));
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if (to_tempfile || !has_symlinks) {
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if (to_tempfile) {
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strcpy(path, ".merge_link_XXXXXX");
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fd = mkstemp(path);
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} else
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fd = create_file(path, 0666);
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if (fd < 0) {
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free(new);
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return error("git checkout-index: unable to create "
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"file %s (%s)", path, strerror(errno));
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}
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wrote = write_in_full(fd, new, size);
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close(fd);
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free(new);
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if (wrote != size)
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return error("git checkout-index: unable to write file %s",
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path);
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} else {
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wrote = symlink(new, path);
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free(new);
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if (wrote)
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return error("git checkout-index: unable to create "
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"symlink %s (%s)", path, strerror(errno));
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}
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break;
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case S_IFGITLINK:
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if (to_tempfile)
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return error("git checkout-index: cannot create temporary subproject %s", path);
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if (mkdir(path, 0777) < 0)
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return error("git checkout-index: cannot create subproject directory %s", path);
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break;
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default:
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return error("git checkout-index: unknown file mode for %s", path);
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}
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if (state->refresh_cache) {
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struct stat st;
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lstat(ce->name, &st);
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fill_stat_cache_info(ce, &st);
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}
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return 0;
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}
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int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *topath)
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{
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static char path[PATH_MAX + 1];
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struct stat st;
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int len = state->base_dir_len;
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if (topath)
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return write_entry(ce, topath, state, 1);
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memcpy(path, state->base_dir, len);
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strcpy(path + len, ce->name);
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if (!lstat(path, &st)) {
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unsigned changed = ce_match_stat(ce, &st, CE_MATCH_IGNORE_VALID);
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if (!changed)
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return 0;
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if (!state->force) {
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if (!state->quiet)
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fprintf(stderr, "git-checkout-index: %s already exists\n", path);
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return -1;
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}
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/*
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* We unlink the old file, to get the new one with the
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* right permissions (including umask, which is nasty
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* to emulate by hand - much easier to let the system
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* just do the right thing)
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*/
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if (S_ISDIR(st.st_mode)) {
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/* If it is a gitlink, leave it alone! */
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if (S_ISGITLINK(ce->ce_mode))
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return 0;
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if (!state->force)
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return error("%s is a directory", path);
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remove_subtree(path);
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} else if (unlink(path))
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return error("unable to unlink old '%s' (%s)", path, strerror(errno));
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} else if (state->not_new)
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return 0;
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create_directories(path, state);
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return write_entry(ce, path, state, 0);
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}
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