git/statinfo.h
Junio C Hamano c33fa871a5 cache: add fake_lstat()
At times, we may already know that a path represented by a
cache_entry ce has no changes via some out-of-line means, like
fsmonitor, and yet need the control to go through a codepath that
requires us to have "struct stat" obtained by lstat() on the path,
for various purposes (e.g. "ie_match_stat()" wants cached stat-info
is still current wrt "struct stat", "diff" wants to know st_mode).

The callers of lstat() on a tracked file, when its cache_entry knows
it is up-to-date, can instead call this helper to pretend that it
called lstat() by faking the "struct stat" information.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-09-15 17:08:46 -07:00

98 lines
2.6 KiB
C

#ifndef STATINFO_H
#define STATINFO_H
struct index_state;
/*
* The "cache_time" is just the low 32 bits of the
* time. It doesn't matter if it overflows - we only
* check it for equality in the 32 bits we save.
*/
struct cache_time {
uint32_t sec;
uint32_t nsec;
};
struct stat_data {
struct cache_time sd_ctime;
struct cache_time sd_mtime;
unsigned int sd_dev;
unsigned int sd_ino;
unsigned int sd_uid;
unsigned int sd_gid;
unsigned int sd_size;
};
/*
* A struct to encapsulate the concept of whether a file has changed
* since we last checked it. This uses criteria similar to those used
* for the index.
*/
struct stat_validity {
struct stat_data *sd;
};
#define MTIME_CHANGED 0x0001
#define CTIME_CHANGED 0x0002
#define OWNER_CHANGED 0x0004
#define MODE_CHANGED 0x0008
#define INODE_CHANGED 0x0010
#define DATA_CHANGED 0x0020
#define TYPE_CHANGED 0x0040
/*
* Record to sd the data from st that we use to check whether a file
* might have changed.
*/
void fill_stat_data(struct stat_data *sd, struct stat *st);
/*
* The inverse of the above. When we know the cache_entry that
* contains sd is up-to-date, but still need to pretend we called
* lstat() to learn that fact, this function fills "st" enough to
* fool ie_match_stat().
*/
void fake_lstat_data(const struct stat_data *sd, struct stat *st);
/*
* Return 0 if st is consistent with a file not having been changed
* since sd was filled. If there are differences, return a
* combination of MTIME_CHANGED, CTIME_CHANGED, OWNER_CHANGED,
* INODE_CHANGED, and DATA_CHANGED.
*/
int match_stat_data(const struct stat_data *sd, struct stat *st);
void stat_validity_clear(struct stat_validity *sv);
/*
* Returns 1 if the path is a regular file (or a symlink to a regular
* file) and matches the saved stat_validity, 0 otherwise. A missing
* or inaccessible file is considered a match if the struct was just
* initialized, or if the previous update found an inaccessible file.
*/
int stat_validity_check(struct stat_validity *sv, const char *path);
/*
* Update the stat_validity from a file opened at descriptor fd. If
* the file is missing, inaccessible, or not a regular file, then
* future calls to stat_validity_check will match iff one of those
* conditions continues to be true.
*/
void stat_validity_update(struct stat_validity *sv, int fd);
#if defined(DT_UNKNOWN) && !defined(NO_D_TYPE_IN_DIRENT)
#define DTYPE(de) ((de)->d_type)
#else
#undef DT_UNKNOWN
#undef DT_DIR
#undef DT_REG
#undef DT_LNK
#define DT_UNKNOWN 0
#define DT_DIR 1
#define DT_REG 2
#define DT_LNK 3
#define DTYPE(de) DT_UNKNOWN
#endif
#endif