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[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
16 #define MAX_TREES 8
17 static int nr_trees;
18 static struct tree *trees[MAX_TREES];
19
20 static int list_tree(unsigned char *sha1)
21 {
22         struct tree *tree;
23
24         if (nr_trees >= MAX_TREES)
25                 die("I cannot read more than %d trees", MAX_TREES);
26         tree = parse_tree_indirect(sha1);
27         if (!tree)
28                 return -1;
29         trees[nr_trees++] = tree;
30         return 0;
31 }
32
33 static int read_cache_unmerged(void)
34 {
35         int i;
36         struct cache_entry **dst;
37         struct cache_entry *last = NULL;
38
39         read_cache();
40         dst = active_cache;
41         for (i = 0; i < active_nr; i++) {
42                 struct cache_entry *ce = active_cache[i];
43                 if (ce_stage(ce)) {
44                         if (last && !strcmp(ce->name, last->name))
45                                 continue;
46                         cache_tree_invalidate_path(active_cache_tree, ce->name);
47                         last = ce;
48                         ce->ce_mode = 0;
49                         ce->ce_flags &= ~htons(CE_STAGEMASK);
50                 }
51                 *dst++ = ce;
52         }
53         active_nr = dst - active_cache;
54         return !!last;
55 }
56
57 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
58 {
59         struct tree_desc desc;
60         struct name_entry entry;
61         int cnt;
62
63         hashcpy(it->sha1, tree->object.sha1);
64         init_tree_desc(&desc, tree->buffer, tree->size);
65         cnt = 0;
66         while (tree_entry(&desc, &entry)) {
67                 if (!S_ISDIR(entry.mode))
68                         cnt++;
69                 else {
70                         struct cache_tree_sub *sub;
71                         struct tree *subtree = lookup_tree(entry.sha1);
72                         if (!subtree->object.parsed)
73                                 parse_tree(subtree);
74                         sub = cache_tree_sub(it, entry.path);
75                         sub->cache_tree = cache_tree();
76                         prime_cache_tree_rec(sub->cache_tree, subtree);
77                         cnt += sub->cache_tree->entry_count;
78                 }
79         }
80         it->entry_count = cnt;
81 }
82
83 static void prime_cache_tree(void)
84 {
85         if (!nr_trees)
86                 return;
87         active_cache_tree = cache_tree();
88         prime_cache_tree_rec(active_cache_tree, trees[0]);
89
90 }
91
92 static const char read_tree_usage[] = "git-read-tree (<sha> | [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] [--exclude-per-directory=<gitignore>] [--index-output=<file>] <sha1> [<sha2> [<sha3>]])";
93
94 static struct lock_file lock_file;
95
96 int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
97 {
98         int i, newfd, stage = 0;
99         unsigned char sha1[20];
100         struct tree_desc t[MAX_TREES];
101         struct unpack_trees_options opts;
102
103         memset(&opts, 0, sizeof(opts));
104         opts.head_idx = -1;
105
106         git_config(git_default_config);
107
108         newfd = hold_locked_index(&lock_file, 1);
109
110         git_config(git_default_config);
111
112         for (i = 1; i < argc; i++) {
113                 const char *arg = argv[i];
114
115                 /* "-u" means "update", meaning that a merge will update
116                  * the working tree.
117                  */
118                 if (!strcmp(arg, "-u")) {
119                         opts.update = 1;
120                         continue;
121                 }
122
123                 if (!strcmp(arg, "-v")) {
124                         opts.verbose_update = 1;
125                         continue;
126                 }
127
128                 /* "-i" means "index only", meaning that a merge will
129                  * not even look at the working tree.
130                  */
131                 if (!strcmp(arg, "-i")) {
132                         opts.index_only = 1;
133                         continue;
134                 }
135
136                 if (!prefixcmp(arg, "--index-output=")) {
137                         set_alternate_index_output(arg + 15);
138                         continue;
139                 }
140
141                 /* "--prefix=<subdirectory>/" means keep the current index
142                  *  entries and put the entries from the tree under the
143                  * given subdirectory.
144                  */
145                 if (!prefixcmp(arg, "--prefix=")) {
146                         if (stage || opts.merge || opts.prefix)
147                                 usage(read_tree_usage);
148                         opts.prefix = arg + 9;
149                         opts.merge = 1;
150                         stage = 1;
151                         if (read_cache_unmerged())
152                                 die("you need to resolve your current index first");
153                         continue;
154                 }
155
156                 /* This differs from "-m" in that we'll silently ignore
157                  * unmerged entries and overwrite working tree files that
158                  * correspond to them.
159                  */
160                 if (!strcmp(arg, "--reset")) {
161                         if (stage || opts.merge || opts.prefix)
162                                 usage(read_tree_usage);
163                         opts.reset = 1;
164                         opts.merge = 1;
165                         stage = 1;
166                         read_cache_unmerged();
167                         continue;
168                 }
169
170                 if (!strcmp(arg, "--trivial")) {
171                         opts.trivial_merges_only = 1;
172                         continue;
173                 }
174
175                 if (!strcmp(arg, "--aggressive")) {
176                         opts.aggressive = 1;
177                         continue;
178                 }
179
180                 /* "-m" stands for "merge", meaning we start in stage 1 */
181                 if (!strcmp(arg, "-m")) {
182                         if (stage || opts.merge || opts.prefix)
183                                 usage(read_tree_usage);
184                         if (read_cache_unmerged())
185                                 die("you need to resolve your current index first");
186                         stage = 1;
187                         opts.merge = 1;
188                         continue;
189                 }
190
191                 if (!prefixcmp(arg, "--exclude-per-directory=")) {
192                         struct dir_struct *dir;
193
194                         if (opts.dir)
195                                 die("more than one --exclude-per-directory are given.");
196
197                         dir = xcalloc(1, sizeof(*opts.dir));
198                         dir->show_ignored = 1;
199                         dir->exclude_per_dir = arg + 24;
200                         opts.dir = dir;
201                         /* We do not need to nor want to do read-directory
202                          * here; we are merely interested in reusing the
203                          * per directory ignore stack mechanism.
204                          */
205                         continue;
206                 }
207
208                 /* using -u and -i at the same time makes no sense */
209                 if (1 < opts.index_only + opts.update)
210                         usage(read_tree_usage);
211
212                 if (get_sha1(arg, sha1))
213                         die("Not a valid object name %s", arg);
214                 if (list_tree(sha1) < 0)
215                         die("failed to unpack tree object %s", arg);
216                 stage++;
217         }
218         if ((opts.update||opts.index_only) && !opts.merge)
219                 usage(read_tree_usage);
220         if ((opts.dir && !opts.update))
221                 die("--exclude-per-directory is meaningless unless -u");
222
223         if (opts.prefix) {
224                 int pfxlen = strlen(opts.prefix);
225                 int pos;
226                 if (opts.prefix[pfxlen-1] != '/')
227                         die("prefix must end with /");
228                 if (stage != 2)
229                         die("binding merge takes only one tree");
230                 pos = cache_name_pos(opts.prefix, pfxlen);
231                 if (0 <= pos)
232                         die("corrupt index file");
233                 pos = -pos-1;
234                 if (pos < active_nr &&
235                     !strncmp(active_cache[pos]->name, opts.prefix, pfxlen))
236                         die("subdirectory '%s' already exists.", opts.prefix);
237                 pos = cache_name_pos(opts.prefix, pfxlen-1);
238                 if (0 <= pos)
239                         die("file '%.*s' already exists.",
240                                         pfxlen-1, opts.prefix);
241                 opts.pos = -1 - pos;
242         }
243
244         if (opts.merge) {
245                 if (stage < 2)
246                         die("just how do you expect me to merge %d trees?", stage-1);
247                 switch (stage - 1) {
248                 case 1:
249                         opts.fn = opts.prefix ? bind_merge : oneway_merge;
250                         break;
251                 case 2:
252                         opts.fn = twoway_merge;
253                         break;
254                 case 3:
255                 default:
256                         opts.fn = threeway_merge;
257                         cache_tree_free(&active_cache_tree);
258                         break;
259                 }
260
261                 if (stage - 1 >= 3)
262                         opts.head_idx = stage - 2;
263                 else
264                         opts.head_idx = 1;
265         }
266
267         for (i = 0; i < nr_trees; i++) {
268                 struct tree *tree = trees[i];
269                 parse_tree(tree);
270                 init_tree_desc(t+i, tree->buffer, tree->size);
271         }
272         unpack_trees(nr_trees, t, &opts);
273
274         /*
275          * When reading only one tree (either the most basic form,
276          * "-m ent" or "--reset ent" form), we can obtain a fully
277          * valid cache-tree because the index must match exactly
278          * what came from the tree.
279          */
280         if (nr_trees && !opts.prefix && (!opts.merge || (stage == 2))) {
281                 cache_tree_free(&active_cache_tree);
282                 prime_cache_tree();
283         }
284
285         if (write_cache(newfd, active_cache, active_nr) ||
286             close(newfd) || commit_locked_index(&lock_file))
287                 die("unable to write new index file");
288         return 0;
289 }