Merge branch 'jc/show-merge'
[git] / builtin-write-tree.c
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"
10
11 static const char write_tree_usage[] =
12 "git-write-tree [--missing-ok] [--prefix=<prefix>/]";
13
14 int write_tree(unsigned char *sha1, int missing_ok, const char *prefix)
15 {
16         int entries, was_valid, newfd;
17
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));
20
21         newfd = hold_lock_file_for_update(lock_file, get_index_file());
22
23         entries = read_cache();
24         if (entries < 0)
25                 die("git-write-tree: error reading cache");
26
27         if (!active_cache_tree)
28                 active_cache_tree = cache_tree();
29
30         was_valid = cache_tree_fully_valid(active_cache_tree);
31
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                 }
42                 /* Not being able to write is fine -- we are only interested
43                  * in updating the cache-tree part, and if the next caller
44                  * ends up using the old index with unupdated cache-tree part
45                  * it misses the work we did here, but that is just a
46                  * performance penalty and not a big deal.
47                  */
48         }
49
50         if (prefix) {
51                 struct cache_tree *subtree =
52                         cache_tree_find(active_cache_tree, prefix);
53                 memcpy(sha1, subtree->sha1, 20);
54         }
55         else
56                 memcpy(sha1, active_cache_tree->sha1, 20);
57
58         rollback_lock_file(lock_file);
59
60         return 0;
61 }
62
63 int cmd_write_tree(int argc, const char **argv, char **envp)
64 {
65         int missing_ok = 0, ret;
66         const char *prefix = NULL;
67         unsigned char sha1[20];
68
69         setup_git_directory();
70
71         while (1 < argc) {
72                 const char *arg = argv[1];
73                 if (!strcmp(arg, "--missing-ok"))
74                         missing_ok = 1;
75                 else if (!strncmp(arg, "--prefix=", 9))
76                         prefix = arg + 9;
77                 else
78                         die(write_tree_usage);
79                 argc--; argv++;
80         }
81
82         if (argc > 2)
83                 die("too many options");
84
85         ret = write_tree(sha1, missing_ok, prefix);
86         printf("%s\n", sha1_to_hex(sha1));
87
88         return ret;
89 }