mirror of
https://github.com/git/git.git
synced 2024-11-19 07:24:50 +01:00
bda6eb0da9
If you want to completely clear the contents of the lstat_cache(), then call this new function. Signed-off-by: Kjetil Barvik <barvik@broadpark.no> Signed-off-by: Junio C Hamano <gitster@pobox.com>
241 lines
6.8 KiB
C
241 lines
6.8 KiB
C
#include "cache.h"
|
|
|
|
static struct cache_def {
|
|
char path[PATH_MAX + 1];
|
|
int len;
|
|
int flags;
|
|
int track_flags;
|
|
int prefix_len_stat_func;
|
|
} cache;
|
|
|
|
/*
|
|
* Returns the length (on a path component basis) of the longest
|
|
* common prefix match of 'name' and the cached path string.
|
|
*/
|
|
static inline int longest_match_lstat_cache(int len, const char *name,
|
|
int *previous_slash)
|
|
{
|
|
int max_len, match_len = 0, match_len_prev = 0, i = 0;
|
|
|
|
max_len = len < cache.len ? len : cache.len;
|
|
while (i < max_len && name[i] == cache.path[i]) {
|
|
if (name[i] == '/') {
|
|
match_len_prev = match_len;
|
|
match_len = i;
|
|
}
|
|
i++;
|
|
}
|
|
/* Is the cached path string a substring of 'name'? */
|
|
if (i == cache.len && cache.len < len && name[cache.len] == '/') {
|
|
match_len_prev = match_len;
|
|
match_len = cache.len;
|
|
/* Is 'name' a substring of the cached path string? */
|
|
} else if ((i == len && len < cache.len && cache.path[len] == '/') ||
|
|
(i == len && len == cache.len)) {
|
|
match_len_prev = match_len;
|
|
match_len = len;
|
|
}
|
|
*previous_slash = match_len_prev;
|
|
return match_len;
|
|
}
|
|
|
|
static inline void reset_lstat_cache(int track_flags, int prefix_len_stat_func)
|
|
{
|
|
cache.path[0] = '\0';
|
|
cache.len = 0;
|
|
cache.flags = 0;
|
|
cache.track_flags = track_flags;
|
|
cache.prefix_len_stat_func = prefix_len_stat_func;
|
|
}
|
|
|
|
#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(int len, const char *name,
|
|
int track_flags, int prefix_len_stat_func)
|
|
{
|
|
int match_len, last_slash, last_slash_dir, previous_slash;
|
|
int match_flags, ret_flags, 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 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(track_flags, 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_match_lstat_cache(len, name, &previous_slash);
|
|
match_flags = cache.flags & track_flags & (FL_NOENT|FL_SYMLINK);
|
|
if (match_flags && match_len == cache.len)
|
|
return match_flags;
|
|
/*
|
|
* 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.
|
|
*/
|
|
match_flags = track_flags & FL_DIR;
|
|
if (match_flags && len == match_len)
|
|
return match_flags;
|
|
}
|
|
|
|
/*
|
|
* 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(track_flags, prefix_len_stat_func);
|
|
}
|
|
return ret_flags;
|
|
}
|
|
|
|
/*
|
|
* Invalidate the given 'name' from the cache, if 'name' matches
|
|
* completely with the cache.
|
|
*/
|
|
void invalidate_lstat_cache(int len, const char *name)
|
|
{
|
|
int match_len, previous_slash;
|
|
|
|
match_len = longest_match_lstat_cache(len, name, &previous_slash);
|
|
if (len == match_len) {
|
|
if ((cache.track_flags & FL_DIR) && previous_slash > 0) {
|
|
cache.path[previous_slash] = '\0';
|
|
cache.len = previous_slash;
|
|
cache.flags = FL_DIR;
|
|
} else
|
|
reset_lstat_cache(cache.track_flags,
|
|
cache.prefix_len_stat_func);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Completely clear the contents of the cache
|
|
*/
|
|
void clear_lstat_cache(void)
|
|
{
|
|
reset_lstat_cache(0, 0);
|
|
}
|
|
|
|
#define USE_ONLY_LSTAT 0
|
|
|
|
/*
|
|
* Return non-zero if path 'name' has a leading symlink component
|
|
*/
|
|
int has_symlink_leading_path(int len, const char *name)
|
|
{
|
|
return lstat_cache(len, name,
|
|
FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) &
|
|
FL_SYMLINK;
|
|
}
|
|
|
|
/*
|
|
* Return non-zero if path 'name' has a leading symlink component or
|
|
* if some leading path component does not exists.
|
|
*/
|
|
int has_symlink_or_noent_leading_path(int len, const char *name)
|
|
{
|
|
return lstat_cache(len, name,
|
|
FL_SYMLINK|FL_NOENT|FL_DIR, USE_ONLY_LSTAT) &
|
|
(FL_SYMLINK|FL_NOENT);
|
|
}
|
|
|
|
/*
|
|
* 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(int len, const char *name, int prefix_len)
|
|
{
|
|
return lstat_cache(len, name,
|
|
FL_DIR|FL_FULLPATH, prefix_len) &
|
|
FL_DIR;
|
|
}
|