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git/builtin-write-tree.c
Linus Torvalds 9ec398d200 Fix racy-git handling in git-write-tree.
After git-write-tree finishes computing the tree, it updates the
index so that later operations can take advantage of fully
populated cache tree.

However, anybody writing the index file has to mark the entries
that are racily clean.  For each entry whose cached lstat(3)
data in the index exactly matches what is obtained from the
filesystem, if the timestamp on the index file was the same or
older than the modification timestamp of the file, the blob
contents and the work tree file, after convert_to_git(), need to
be compared, and if they are different, its index entry needs to
be marked not to match the lstat(3) data from the filesystem.

In order for this to work, convert_to_git() needs to work
correctly, which in turn means you need to read the config file
to get the settings of core.crlf and friends.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-08-24 18:53:02 -07:00

94 lines
2.2 KiB
C

/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "builtin.h"
#include "cache.h"
#include "tree.h"
#include "cache-tree.h"
static const char write_tree_usage[] =
"git-write-tree [--missing-ok] [--prefix=<prefix>/]";
int write_tree(unsigned char *sha1, int missing_ok, const char *prefix)
{
int entries, was_valid, newfd;
/* We can't free this memory, it becomes part of a linked list parsed atexit() */
struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
newfd = hold_locked_index(lock_file, 1);
entries = read_cache();
if (entries < 0)
die("git-write-tree: error reading cache");
if (!active_cache_tree)
active_cache_tree = cache_tree();
was_valid = cache_tree_fully_valid(active_cache_tree);
if (!was_valid) {
if (cache_tree_update(active_cache_tree,
active_cache, active_nr,
missing_ok, 0) < 0)
die("git-write-tree: error building trees");
if (0 <= newfd) {
if (!write_cache(newfd, active_cache, active_nr)
&& !close(newfd)) {
commit_lock_file(lock_file);
newfd = -1;
}
}
/* Not being able to write is fine -- we are only interested
* in updating the cache-tree part, and if the next caller
* ends up using the old index with unupdated cache-tree part
* it misses the work we did here, but that is just a
* performance penalty and not a big deal.
*/
}
if (prefix) {
struct cache_tree *subtree =
cache_tree_find(active_cache_tree, prefix);
if (!subtree)
die("git-write-tree: prefix %s not found", prefix);
hashcpy(sha1, subtree->sha1);
}
else
hashcpy(sha1, active_cache_tree->sha1);
if (0 <= newfd)
close(newfd);
rollback_lock_file(lock_file);
return 0;
}
int cmd_write_tree(int argc, const char **argv, const char *unused_prefix)
{
int missing_ok = 0, ret;
const char *prefix = NULL;
unsigned char sha1[20];
git_config(git_default_config);
while (1 < argc) {
const char *arg = argv[1];
if (!strcmp(arg, "--missing-ok"))
missing_ok = 1;
else if (!prefixcmp(arg, "--prefix="))
prefix = arg + 9;
else
usage(write_tree_usage);
argc--; argv++;
}
if (argc > 2)
die("too many options");
ret = write_tree(sha1, missing_ok, prefix);
printf("%s\n", sha1_to_hex(sha1));
return ret;
}