gc --auto: do not lock refs in the background
[git] / builtin / read-tree.c
1 /*
2  * GIT - The information manager from hell
3  *
4  * Copyright (C) Linus Torvalds, 2005
5  */
6
7 #include "cache.h"
8 #include "object.h"
9 #include "tree.h"
10 #include "tree-walk.h"
11 #include "cache-tree.h"
12 #include "unpack-trees.h"
13 #include "dir.h"
14 #include "builtin.h"
15 #include "parse-options.h"
16 #include "resolve-undo.h"
17
18 static int nr_trees;
19 static int read_empty;
20 static struct tree *trees[MAX_UNPACK_TREES];
21
22 static int list_tree(unsigned char *sha1)
23 {
24         struct tree *tree;
25
26         if (nr_trees >= MAX_UNPACK_TREES)
27                 die("I cannot read more than %d trees", MAX_UNPACK_TREES);
28         tree = parse_tree_indirect(sha1);
29         if (!tree)
30                 return -1;
31         trees[nr_trees++] = tree;
32         return 0;
33 }
34
35 static const char * const read_tree_usage[] = {
36         N_("git read-tree [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u [--exclude-per-directory=<gitignore>] | -i]] [--no-sparse-checkout] [--index-output=<file>] (--empty | <tree-ish1> [<tree-ish2> [<tree-ish3>]])"),
37         NULL
38 };
39
40 static int index_output_cb(const struct option *opt, const char *arg,
41                                  int unset)
42 {
43         set_alternate_index_output(arg);
44         return 0;
45 }
46
47 static int exclude_per_directory_cb(const struct option *opt, const char *arg,
48                                     int unset)
49 {
50         struct dir_struct *dir;
51         struct unpack_trees_options *opts;
52
53         opts = (struct unpack_trees_options *)opt->value;
54
55         if (opts->dir)
56                 die("more than one --exclude-per-directory given.");
57
58         dir = xcalloc(1, sizeof(*opts->dir));
59         dir->flags |= DIR_SHOW_IGNORED;
60         dir->exclude_per_dir = arg;
61         opts->dir = dir;
62         /* We do not need to nor want to do read-directory
63          * here; we are merely interested in reusing the
64          * per directory ignore stack mechanism.
65          */
66         return 0;
67 }
68
69 static void debug_stage(const char *label, const struct cache_entry *ce,
70                         struct unpack_trees_options *o)
71 {
72         printf("%s ", label);
73         if (!ce)
74                 printf("(missing)\n");
75         else if (ce == o->df_conflict_entry)
76                 printf("(conflict)\n");
77         else
78                 printf("%06o #%d %s %.8s\n",
79                        ce->ce_mode, ce_stage(ce), ce->name,
80                        sha1_to_hex(ce->sha1));
81 }
82
83 static int debug_merge(const struct cache_entry * const *stages,
84                        struct unpack_trees_options *o)
85 {
86         int i;
87
88         printf("* %d-way merge\n", o->merge_size);
89         debug_stage("index", stages[0], o);
90         for (i = 1; i <= o->merge_size; i++) {
91                 char buf[24];
92                 sprintf(buf, "ent#%d", i);
93                 debug_stage(buf, stages[i], o);
94         }
95         return 0;
96 }
97
98 static struct lock_file lock_file;
99
100 int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
101 {
102         int i, newfd, stage = 0;
103         unsigned char sha1[20];
104         struct tree_desc t[MAX_UNPACK_TREES];
105         struct unpack_trees_options opts;
106         int prefix_set = 0;
107         const struct option read_tree_options[] = {
108                 { OPTION_CALLBACK, 0, "index-output", NULL, N_("file"),
109                   N_("write resulting index to <file>"),
110                   PARSE_OPT_NONEG, index_output_cb },
111                 OPT_SET_INT(0, "empty", &read_empty,
112                             N_("only empty the index"), 1),
113                 OPT__VERBOSE(&opts.verbose_update, N_("be verbose")),
114                 OPT_GROUP(N_("Merging")),
115                 OPT_SET_INT('m', NULL, &opts.merge,
116                             N_("perform a merge in addition to a read"), 1),
117                 OPT_SET_INT(0, "trivial", &opts.trivial_merges_only,
118                             N_("3-way merge if no file level merging required"), 1),
119                 OPT_SET_INT(0, "aggressive", &opts.aggressive,
120                             N_("3-way merge in presence of adds and removes"), 1),
121                 OPT_SET_INT(0, "reset", &opts.reset,
122                             N_("same as -m, but discard unmerged entries"), 1),
123                 { OPTION_STRING, 0, "prefix", &opts.prefix, N_("<subdirectory>/"),
124                   N_("read the tree into the index under <subdirectory>/"),
125                   PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP },
126                 OPT_SET_INT('u', NULL, &opts.update,
127                             N_("update working tree with merge result"), 1),
128                 { OPTION_CALLBACK, 0, "exclude-per-directory", &opts,
129                   N_("gitignore"),
130                   N_("allow explicitly ignored files to be overwritten"),
131                   PARSE_OPT_NONEG, exclude_per_directory_cb },
132                 OPT_SET_INT('i', NULL, &opts.index_only,
133                             N_("don't check the working tree after merging"), 1),
134                 OPT__DRY_RUN(&opts.dry_run, N_("don't update the index or the work tree")),
135                 OPT_SET_INT(0, "no-sparse-checkout", &opts.skip_sparse_checkout,
136                             N_("skip applying sparse checkout filter"), 1),
137                 OPT_SET_INT(0, "debug-unpack", &opts.debug_unpack,
138                             N_("debug unpack-trees"), 1),
139                 OPT_END()
140         };
141
142         memset(&opts, 0, sizeof(opts));
143         opts.head_idx = -1;
144         opts.src_index = &the_index;
145         opts.dst_index = &the_index;
146
147         git_config(git_default_config, NULL);
148
149         argc = parse_options(argc, argv, unused_prefix, read_tree_options,
150                              read_tree_usage, 0);
151
152         newfd = hold_locked_index(&lock_file, 1);
153
154         prefix_set = opts.prefix ? 1 : 0;
155         if (1 < opts.merge + opts.reset + prefix_set)
156                 die("Which one? -m, --reset, or --prefix?");
157
158         if (opts.reset || opts.merge || opts.prefix) {
159                 if (read_cache_unmerged() && (opts.prefix || opts.merge))
160                         die("You need to resolve your current index first");
161                 stage = opts.merge = 1;
162         }
163         resolve_undo_clear();
164
165         for (i = 0; i < argc; i++) {
166                 const char *arg = argv[i];
167
168                 if (get_sha1(arg, sha1))
169                         die("Not a valid object name %s", arg);
170                 if (list_tree(sha1) < 0)
171                         die("failed to unpack tree object %s", arg);
172                 stage++;
173         }
174         if (nr_trees == 0 && !read_empty)
175                 warning("read-tree: emptying the index with no arguments is deprecated; use --empty");
176         else if (nr_trees > 0 && read_empty)
177                 die("passing trees as arguments contradicts --empty");
178
179         if (1 < opts.index_only + opts.update)
180                 die("-u and -i at the same time makes no sense");
181         if ((opts.update || opts.index_only) && !opts.merge)
182                 die("%s is meaningless without -m, --reset, or --prefix",
183                     opts.update ? "-u" : "-i");
184         if ((opts.dir && !opts.update))
185                 die("--exclude-per-directory is meaningless unless -u");
186         if (opts.merge && !opts.index_only)
187                 setup_work_tree();
188
189         if (opts.merge) {
190                 if (stage < 2)
191                         die("just how do you expect me to merge %d trees?", stage-1);
192                 switch (stage - 1) {
193                 case 1:
194                         opts.fn = opts.prefix ? bind_merge : oneway_merge;
195                         break;
196                 case 2:
197                         opts.fn = twoway_merge;
198                         opts.initial_checkout = is_cache_unborn();
199                         break;
200                 case 3:
201                 default:
202                         opts.fn = threeway_merge;
203                         break;
204                 }
205
206                 if (stage - 1 >= 3)
207                         opts.head_idx = stage - 2;
208                 else
209                         opts.head_idx = 1;
210         }
211
212         if (opts.debug_unpack)
213                 opts.fn = debug_merge;
214
215         cache_tree_free(&active_cache_tree);
216         for (i = 0; i < nr_trees; i++) {
217                 struct tree *tree = trees[i];
218                 parse_tree(tree);
219                 init_tree_desc(t+i, tree->buffer, tree->size);
220         }
221         if (unpack_trees(nr_trees, t, &opts))
222                 return 128;
223
224         if (opts.debug_unpack || opts.dry_run)
225                 return 0; /* do not write the index out */
226
227         /*
228          * When reading only one tree (either the most basic form,
229          * "-m ent" or "--reset ent" form), we can obtain a fully
230          * valid cache-tree because the index must match exactly
231          * what came from the tree.
232          */
233         if (nr_trees == 1 && !opts.prefix)
234                 prime_cache_tree(&active_cache_tree, trees[0]);
235
236         if (write_cache(newfd, active_cache, active_nr) ||
237             commit_locked_index(&lock_file))
238                 die("unable to write new index file");
239         return 0;
240 }