Update the index format documentation to mention the v4 format.
* nd/doc-index-format:
update-index: list supported idx versions and their features
read-cache.c: use INDEX_FORMAT_{LB,UB} in verify_hdr()
index-format.txt: mention of v4 is missing in some places
When these flags are specified, the object names recorded
for the paths are not updated. Instead, these options
set and unset the "assume unchanged" bit for the
- paths. When the "assume unchanged" bit is on, git stops
+ paths. When the "assume unchanged" bit is on, Git stops
checking the working tree files for possible
modifications, so you need to manually unset the bit to
- tell git when you change the working tree file. This is
+ tell Git when you change the working tree file. This is
sometimes helpful when working with a big project on a
filesystem that has very slow lstat(2) system call
(e.g. cifs).
--index-version <n>::
Write the resulting index out in the named on-disk format version.
- The current default version is 2.
+ Supported versions are 2, 3 and 4. The current default version is 2
+ or 3, depending on whether extra features are used, such as
+ `git add -N`.
+ +
+ Version 4 performs a simple pathname compression that reduces index
+ size by 30%-50% on large repositories, which results in faster load
+ time. Version 4 is relatively young (first released in in 1.8.0 in
+ October 2012). Other Git implementations such as JGit and libgit2
+ may not support it yet.
-z::
Only meaningful with `--stdin` or `--index-info`; paths are
Using ``assume unchanged'' bit
------------------------------
-Many operations in git depend on your filesystem to have an
+Many operations in Git depend on your filesystem to have an
efficient `lstat(2)` implementation, so that `st_mtime`
information for working tree files can be cheaply checked to see
if the file contents have changed from the version recorded in
the index file. Unfortunately, some filesystems have
inefficient `lstat(2)`. If your filesystem is one of them, you
can set "assume unchanged" bit to paths you have not changed to
-cause git not to do this check. Note that setting this bit on a
-path does not mean git will check the contents of the file to
-see if it has changed -- it makes git to omit any checking and
+cause Git not to do this check. Note that setting this bit on a
+path does not mean Git will check the contents of the file to
+see if it has changed -- it makes Git to omit any checking and
assume it has *not* changed. When you make changes to working
-tree files, you have to explicitly tell git about it by dropping
+tree files, you have to explicitly tell Git about it by dropping
"assume unchanged" bit, either before or after you modify them.
In order to set "assume unchanged" bit, use `--assume-unchanged`
The command looks at `core.ignorestat` configuration variable. When
this is true, paths updated with `git update-index paths...` and
-paths updated with other git commands that update both index and
+paths updated with other Git commands that update both index and
working tree (e.g. 'git apply --index', 'git checkout-index -u',
and 'git read-tree -u') are automatically marked as "assume
unchanged". Note that "assume unchanged" bit is *not* set if
-GIT index format
+Git index format
================
-== The git index file has the following format
+== The Git index file has the following format
All binary numbers are in network byte order. Version 2 is described
here unless stated otherwise.
The signature is { 'D', 'I', 'R', 'C' } (stands for "dircache")
4-byte version number:
- The current supported versions are 2 and 3.
+ The current supported versions are 2, 3 and 4.
32-bit number of index entries.
- Extensions
Extensions are identified by signature. Optional extensions can
- be ignored if GIT does not understand them.
+ be ignored if Git does not understand them.
- GIT currently supports cached tree and resolve undo extensions.
+ Git currently supports cached tree and resolve undo extensions.
4-byte extension signature. If the first byte is 'A'..'Z' the
extension is optional and can be ignored.
12-bit name length if the length is less than 0xFFF; otherwise 0xFFF
is stored in this field.
- (Version 3) A 16-bit field, only applicable if the "extended flag"
- above is 1, split into (high to low bits).
+ (Version 3 or later) A 16-bit field, only applicable if the
+ "extended flag" above is 1, split into (high to low bits).
1-bit reserved for future
}
if (ce->ce_mtime.sec != (unsigned int)st->st_mtime)
changed |= MTIME_CHANGED;
- if (trust_ctime && ce->ce_ctime.sec != (unsigned int)st->st_ctime)
+ if (trust_ctime && check_stat &&
+ ce->ce_ctime.sec != (unsigned int)st->st_ctime)
changed |= CTIME_CHANGED;
#ifdef USE_NSEC
- if (ce->ce_mtime.nsec != ST_MTIME_NSEC(*st))
+ if (check_stat && ce->ce_mtime.nsec != ST_MTIME_NSEC(*st))
changed |= MTIME_CHANGED;
- if (trust_ctime && ce->ce_ctime.nsec != ST_CTIME_NSEC(*st))
+ if (trust_ctime && check_stat &&
+ ce->ce_ctime.nsec != ST_CTIME_NSEC(*st))
changed |= CTIME_CHANGED;
#endif
- if (ce->ce_uid != (unsigned int) st->st_uid ||
- ce->ce_gid != (unsigned int) st->st_gid)
- changed |= OWNER_CHANGED;
- if (ce->ce_ino != (unsigned int) st->st_ino)
- changed |= INODE_CHANGED;
+ if (check_stat) {
+ if (ce->ce_uid != (unsigned int) st->st_uid ||
+ ce->ce_gid != (unsigned int) st->st_gid)
+ changed |= OWNER_CHANGED;
+ if (ce->ce_ino != (unsigned int) st->st_ino)
+ changed |= INODE_CHANGED;
+ }
#ifdef USE_STDEV
/*
* clients will have different views of what "device"
* the filesystem is on
*/
- if (ce->ce_dev != (unsigned int) st->st_dev)
- changed |= INODE_CHANGED;
+ if (check_stat && ce->ce_dev != (unsigned int) st->st_dev)
+ changed |= INODE_CHANGED;
#endif
if (ce->ce_size != (unsigned int) st->st_size)
if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
return error("bad signature");
hdr_version = ntohl(hdr->hdr_version);
- if (hdr_version < 2 || 4 < hdr_version)
+ if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version)
return error("bad index version %d", hdr_version);
git_SHA1_Init(&c);
git_SHA1_Update(&c, hdr, size - 20);