git-svn: fix log with single revision against a non-HEAD branch
[git/dscho.git] / builtin-write-tree.c
blob88f34ba7d6e2426fae5169eb28b12e93e72082eb
1 /*
2  * GIT - The information manager from hell
3  *
4  * Copyright (C) Linus Torvalds, 2005
5  */
6 #include "builtin.h"
7 #include "cache.h"
8 #include "tree.h"
9 #include "cache-tree.h"
11 static const char write_tree_usage[] =
12 "git-write-tree [--missing-ok] [--prefix=<prefix>/]";
14 int write_tree(unsigned char *sha1, int missing_ok, const char *prefix)
16         int entries, was_valid, newfd;
18         /* We can't free this memory, it becomes part of a linked list parsed atexit() */
19         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
21         newfd = hold_locked_index(lock_file, 1);
23         entries = read_cache();
24         if (entries < 0)
25                 die("git-write-tree: error reading cache");
27         if (!active_cache_tree)
28                 active_cache_tree = cache_tree();
30         was_valid = cache_tree_fully_valid(active_cache_tree);
32         if (!was_valid) {
33                 if (cache_tree_update(active_cache_tree,
34                                       active_cache, active_nr,
35                                       missing_ok, 0) < 0)
36                         die("git-write-tree: error building trees");
37                 if (0 <= newfd) {
38                         if (!write_cache(newfd, active_cache, active_nr)
39                                         && !close(newfd)) {
40                                 commit_lock_file(lock_file);
41                                 newfd = -1;
42                         }
43                 }
44                 /* Not being able to write is fine -- we are only interested
45                  * in updating the cache-tree part, and if the next caller
46                  * ends up using the old index with unupdated cache-tree part
47                  * it misses the work we did here, but that is just a
48                  * performance penalty and not a big deal.
49                  */
50         }
52         if (prefix) {
53                 struct cache_tree *subtree =
54                         cache_tree_find(active_cache_tree, prefix);
55                 if (!subtree)
56                         die("git-write-tree: prefix %s not found", prefix);
57                 hashcpy(sha1, subtree->sha1);
58         }
59         else
60                 hashcpy(sha1, active_cache_tree->sha1);
62         if (0 <= newfd)
63                 close(newfd);
64         rollback_lock_file(lock_file);
66         return 0;
69 int cmd_write_tree(int argc, const char **argv, const char *unused_prefix)
71         int missing_ok = 0, ret;
72         const char *prefix = NULL;
73         unsigned char sha1[20];
75         while (1 < argc) {
76                 const char *arg = argv[1];
77                 if (!strcmp(arg, "--missing-ok"))
78                         missing_ok = 1;
79                 else if (!prefixcmp(arg, "--prefix="))
80                         prefix = arg + 9;
81                 else
82                         usage(write_tree_usage);
83                 argc--; argv++;
84         }
86         if (argc > 2)
87                 die("too many options");
89         ret = write_tree(sha1, missing_ok, prefix);
90         printf("%s\n", sha1_to_hex(sha1));
92         return ret;