mirror of
https://github.com/git/git.git
synced 2024-12-06 00:14:36 +08:00
15438d5a56
check_leading_path() and has_dirs_only_path() both always use the default cache, which could be a caveat for adding parallelism (which is a concern and even a GSoC proposal). Reimplement these two in terms of new threaded_check_leading_path() and threaded_has_dirs_only_path() that take their own copy of the cache. Signed-off-by: Jared Hance <jaredhance@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
328 lines
9.2 KiB
C
328 lines
9.2 KiB
C
#include "cache.h"
|
|
|
|
/*
|
|
* Returns the length (on a path component basis) of the longest
|
|
* common prefix match of 'name_a' and 'name_b'.
|
|
*/
|
|
static int longest_path_match(const char *name_a, int len_a,
|
|
const char *name_b, int len_b,
|
|
int *previous_slash)
|
|
{
|
|
int max_len, match_len = 0, match_len_prev = 0, i = 0;
|
|
|
|
max_len = len_a < len_b ? len_a : len_b;
|
|
while (i < max_len && name_a[i] == name_b[i]) {
|
|
if (name_a[i] == '/') {
|
|
match_len_prev = match_len;
|
|
match_len = i;
|
|
}
|
|
i++;
|
|
}
|
|
/*
|
|
* Is 'name_b' a substring of 'name_a', the other way around,
|
|
* or is 'name_a' and 'name_b' the exact same string?
|
|
*/
|
|
if (i >= max_len && ((len_a > len_b && name_a[len_b] == '/') ||
|
|
(len_a < len_b && name_b[len_a] == '/') ||
|
|
(len_a == len_b))) {
|
|
match_len_prev = match_len;
|
|
match_len = i;
|
|
}
|
|
*previous_slash = match_len_prev;
|
|
return match_len;
|
|
}
|
|
|
|
static struct cache_def default_cache;
|
|
|
|
static inline void reset_lstat_cache(struct cache_def *cache)
|
|
{
|
|
cache->path[0] = '\0';
|
|
cache->len = 0;
|
|
cache->flags = 0;
|
|
/*
|
|
* The track_flags and prefix_len_stat_func members is only
|
|
* set by the safeguard rule inside lstat_cache()
|
|
*/
|
|
}
|
|
|
|
#define FL_DIR (1 << 0)
|
|
#define FL_NOENT (1 << 1)
|
|
#define FL_SYMLINK (1 << 2)
|
|
#define FL_LSTATERR (1 << 3)
|
|
#define FL_ERR (1 << 4)
|
|
#define FL_FULLPATH (1 << 5)
|
|
|
|
/*
|
|
* Check if name 'name' of length 'len' has a symlink leading
|
|
* component, or if the directory exists and is real, or not.
|
|
*
|
|
* To speed up the check, some information is allowed to be cached.
|
|
* This can be indicated by the 'track_flags' argument, which also can
|
|
* be used to indicate that we should check the full path.
|
|
*
|
|
* The 'prefix_len_stat_func' parameter can be used to set the length
|
|
* of the prefix, where the cache should use the stat() function
|
|
* instead of the lstat() function to test each path component.
|
|
*/
|
|
static int lstat_cache_matchlen(struct cache_def *cache,
|
|
const char *name, int len,
|
|
int *ret_flags, int track_flags,
|
|
int prefix_len_stat_func)
|
|
{
|
|
int match_len, last_slash, last_slash_dir, previous_slash;
|
|
int save_flags, max_len, ret;
|
|
struct stat st;
|
|
|
|
if (cache->track_flags != track_flags ||
|
|
cache->prefix_len_stat_func != prefix_len_stat_func) {
|
|
/*
|
|
* As a safeguard rule we clear the cache if the
|
|
* values of track_flags and/or prefix_len_stat_func
|
|
* does not match with the last supplied values.
|
|
*/
|
|
reset_lstat_cache(cache);
|
|
cache->track_flags = track_flags;
|
|
cache->prefix_len_stat_func = prefix_len_stat_func;
|
|
match_len = last_slash = 0;
|
|
} else {
|
|
/*
|
|
* Check to see if we have a match from the cache for
|
|
* the 2 "excluding" path types.
|
|
*/
|
|
match_len = last_slash =
|
|
longest_path_match(name, len, cache->path, cache->len,
|
|
&previous_slash);
|
|
*ret_flags = cache->flags & track_flags & (FL_NOENT|FL_SYMLINK);
|
|
|
|
if (!(track_flags & FL_FULLPATH) && match_len == len)
|
|
match_len = last_slash = previous_slash;
|
|
|
|
if (*ret_flags && match_len == cache->len)
|
|
return match_len;
|
|
/*
|
|
* If we now have match_len > 0, we would know that
|
|
* the matched part will always be a directory.
|
|
*
|
|
* Also, if we are tracking directories and 'name' is
|
|
* a substring of the cache on a path component basis,
|
|
* we can return immediately.
|
|
*/
|
|
*ret_flags = track_flags & FL_DIR;
|
|
if (*ret_flags && len == match_len)
|
|
return match_len;
|
|
}
|
|
|
|
/*
|
|
* Okay, no match from the cache so far, so now we have to
|
|
* check the rest of the path components.
|
|
*/
|
|
*ret_flags = FL_DIR;
|
|
last_slash_dir = last_slash;
|
|
max_len = len < PATH_MAX ? len : PATH_MAX;
|
|
while (match_len < max_len) {
|
|
do {
|
|
cache->path[match_len] = name[match_len];
|
|
match_len++;
|
|
} while (match_len < max_len && name[match_len] != '/');
|
|
if (match_len >= max_len && !(track_flags & FL_FULLPATH))
|
|
break;
|
|
last_slash = match_len;
|
|
cache->path[last_slash] = '\0';
|
|
|
|
if (last_slash <= prefix_len_stat_func)
|
|
ret = stat(cache->path, &st);
|
|
else
|
|
ret = lstat(cache->path, &st);
|
|
|
|
if (ret) {
|
|
*ret_flags = FL_LSTATERR;
|
|
if (errno == ENOENT)
|
|
*ret_flags |= FL_NOENT;
|
|
} else if (S_ISDIR(st.st_mode)) {
|
|
last_slash_dir = last_slash;
|
|
continue;
|
|
} else if (S_ISLNK(st.st_mode)) {
|
|
*ret_flags = FL_SYMLINK;
|
|
} else {
|
|
*ret_flags = FL_ERR;
|
|
}
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* At the end update the cache. Note that max 3 different
|
|
* path types, FL_NOENT, FL_SYMLINK and FL_DIR, can be cached
|
|
* for the moment!
|
|
*/
|
|
save_flags = *ret_flags & track_flags & (FL_NOENT|FL_SYMLINK);
|
|
if (save_flags && last_slash > 0 && last_slash <= PATH_MAX) {
|
|
cache->path[last_slash] = '\0';
|
|
cache->len = last_slash;
|
|
cache->flags = save_flags;
|
|
} else if ((track_flags & FL_DIR) &&
|
|
last_slash_dir > 0 && last_slash_dir <= PATH_MAX) {
|
|
/*
|
|
* We have a separate test for the directory case,
|
|
* since it could be that we have found a symlink or a
|
|
* non-existing directory and the track_flags says
|
|
* that we cannot cache this fact, so the cache would
|
|
* then have been left empty in this case.
|
|
*
|
|
* But if we are allowed to track real directories, we
|
|
* can still cache the path components before the last
|
|
* one (the found symlink or non-existing component).
|
|
*/
|
|
cache->path[last_slash_dir] = '\0';
|
|
cache->len = last_slash_dir;
|
|
cache->flags = FL_DIR;
|
|
} else {
|
|
reset_lstat_cache(cache);
|
|
}
|
|
return match_len;
|
|
}
|
|
|
|
static int lstat_cache(struct cache_def *cache, const char *name, int len,
|
|
int track_flags, int prefix_len_stat_func)
|
|
{
|
|
int flags;
|
|
(void)lstat_cache_matchlen(cache, name, len, &flags, track_flags,
|
|
prefix_len_stat_func);
|
|
return flags;
|
|
}
|
|
|
|
#define USE_ONLY_LSTAT 0
|
|
|
|
/*
|
|
* Return non-zero if path 'name' has a leading symlink component
|
|
*/
|
|
int threaded_has_symlink_leading_path(struct cache_def *cache, const char *name, int len)
|
|
{
|
|
return lstat_cache(cache, name, len, FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) & FL_SYMLINK;
|
|
}
|
|
|
|
/*
|
|
* Return non-zero if path 'name' has a leading symlink component
|
|
*/
|
|
int has_symlink_leading_path(const char *name, int len)
|
|
{
|
|
return threaded_has_symlink_leading_path(&default_cache, name, len);
|
|
}
|
|
|
|
/*
|
|
* Return zero if path 'name' has a leading symlink component or
|
|
* if some leading path component does not exists.
|
|
*
|
|
* Return -1 if leading path exists and is a directory.
|
|
*
|
|
* Return path length if leading path exists and is neither a
|
|
* directory nor a symlink.
|
|
*/
|
|
int check_leading_path(const char *name, int len)
|
|
{
|
|
return threaded_check_leading_path(&default_cache, name, len);
|
|
}
|
|
|
|
/*
|
|
* Return zero if path 'name' has a leading symlink component or
|
|
* if some leading path component does not exists.
|
|
*
|
|
* Return -1 if leading path exists and is a directory.
|
|
*
|
|
* Return path length if leading path exists and is neither a
|
|
* directory nor a symlink.
|
|
*/
|
|
int threaded_check_leading_path(struct cache_def *cache, const char *name, int len)
|
|
{
|
|
int flags;
|
|
int match_len = lstat_cache_matchlen(cache, name, len, &flags,
|
|
FL_SYMLINK|FL_NOENT|FL_DIR, USE_ONLY_LSTAT);
|
|
if (flags & FL_NOENT)
|
|
return 0;
|
|
else if (flags & FL_DIR)
|
|
return -1;
|
|
else
|
|
return match_len;
|
|
}
|
|
|
|
/*
|
|
* Return non-zero if all path components of 'name' exists as a
|
|
* directory. If prefix_len > 0, we will test with the stat()
|
|
* function instead of the lstat() function for a prefix length of
|
|
* 'prefix_len', thus we then allow for symlinks in the prefix part as
|
|
* long as those points to real existing directories.
|
|
*/
|
|
int has_dirs_only_path(const char *name, int len, int prefix_len)
|
|
{
|
|
return threaded_has_dirs_only_path(&default_cache, name, len, prefix_len);
|
|
}
|
|
|
|
/*
|
|
* Return non-zero if all path components of 'name' exists as a
|
|
* directory. If prefix_len > 0, we will test with the stat()
|
|
* function instead of the lstat() function for a prefix length of
|
|
* 'prefix_len', thus we then allow for symlinks in the prefix part as
|
|
* long as those points to real existing directories.
|
|
*/
|
|
int threaded_has_dirs_only_path(struct cache_def *cache, const char *name, int len, int prefix_len)
|
|
{
|
|
return lstat_cache(cache, name, len,
|
|
FL_DIR|FL_FULLPATH, prefix_len) &
|
|
FL_DIR;
|
|
}
|
|
|
|
static struct removal_def {
|
|
char path[PATH_MAX];
|
|
int len;
|
|
} removal;
|
|
|
|
static void do_remove_scheduled_dirs(int new_len)
|
|
{
|
|
while (removal.len > new_len) {
|
|
removal.path[removal.len] = '\0';
|
|
if (rmdir(removal.path))
|
|
break;
|
|
do {
|
|
removal.len--;
|
|
} while (removal.len > new_len &&
|
|
removal.path[removal.len] != '/');
|
|
}
|
|
removal.len = new_len;
|
|
}
|
|
|
|
void schedule_dir_for_removal(const char *name, int len)
|
|
{
|
|
int match_len, last_slash, i, previous_slash;
|
|
|
|
match_len = last_slash = i =
|
|
longest_path_match(name, len, removal.path, removal.len,
|
|
&previous_slash);
|
|
/* Find last slash inside 'name' */
|
|
while (i < len) {
|
|
if (name[i] == '/')
|
|
last_slash = i;
|
|
i++;
|
|
}
|
|
|
|
/*
|
|
* If we are about to go down the directory tree, we check if
|
|
* we must first go upwards the tree, such that we then can
|
|
* remove possible empty directories as we go upwards.
|
|
*/
|
|
if (match_len < last_slash && match_len < removal.len)
|
|
do_remove_scheduled_dirs(match_len);
|
|
/*
|
|
* If we go deeper down the directory tree, we only need to
|
|
* save the new path components as we go down.
|
|
*/
|
|
if (match_len < last_slash) {
|
|
memcpy(&removal.path[match_len], &name[match_len],
|
|
last_slash - match_len);
|
|
removal.len = last_slash;
|
|
}
|
|
}
|
|
|
|
void remove_scheduled_dirs(void)
|
|
{
|
|
do_remove_scheduled_dirs(0);
|
|
}
|