Documentation/technical: document ll_merge
[git] / tree.c
1 #include "cache.h"
2 #include "cache-tree.h"
3 #include "tree.h"
4 #include "blob.h"
5 #include "commit.h"
6 #include "tag.h"
7 #include "tree-walk.h"
8
9 const char *tree_type = "tree";
10
11 static int read_one_entry_opt(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, int opt)
12 {
13         int len;
14         unsigned int size;
15         struct cache_entry *ce;
16
17         if (S_ISDIR(mode))
18                 return READ_TREE_RECURSIVE;
19
20         len = strlen(pathname);
21         size = cache_entry_size(baselen + len);
22         ce = xcalloc(1, size);
23
24         ce->ce_mode = create_ce_mode(mode);
25         ce->ce_flags = create_ce_flags(baselen + len, stage);
26         memcpy(ce->name, base, baselen);
27         memcpy(ce->name + baselen, pathname, len+1);
28         hashcpy(ce->sha1, sha1);
29         return add_cache_entry(ce, opt);
30 }
31
32 static int read_one_entry(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, void *context)
33 {
34         return read_one_entry_opt(sha1, base, baselen, pathname, mode, stage,
35                                   ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
36 }
37
38 /*
39  * This is used when the caller knows there is no existing entries at
40  * the stage that will conflict with the entry being added.
41  */
42 static int read_one_entry_quick(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, void *context)
43 {
44         return read_one_entry_opt(sha1, base, baselen, pathname, mode, stage,
45                                   ADD_CACHE_JUST_APPEND);
46 }
47
48 static int match_tree_entry(const char *base, int baselen, const char *path, unsigned int mode, const char **paths)
49 {
50         const char *match;
51         int pathlen;
52
53         if (!paths)
54                 return 1;
55         pathlen = strlen(path);
56         while ((match = *paths++) != NULL) {
57                 int matchlen = strlen(match);
58
59                 if (baselen >= matchlen) {
60                         /* If it doesn't match, move along... */
61                         if (strncmp(base, match, matchlen))
62                                 continue;
63                         /* pathspecs match only at the directory boundaries */
64                         if (!matchlen ||
65                             baselen == matchlen ||
66                             base[matchlen] == '/' ||
67                             match[matchlen - 1] == '/')
68                                 return 1;
69                         continue;
70                 }
71
72                 /* Does the base match? */
73                 if (strncmp(base, match, baselen))
74                         continue;
75
76                 match += baselen;
77                 matchlen -= baselen;
78
79                 if (pathlen > matchlen)
80                         continue;
81
82                 if (matchlen > pathlen) {
83                         if (match[pathlen] != '/')
84                                 continue;
85                         if (!S_ISDIR(mode))
86                                 continue;
87                 }
88
89                 if (strncmp(path, match, pathlen))
90                         continue;
91
92                 return 1;
93         }
94         return 0;
95 }
96
97 int read_tree_recursive(struct tree *tree,
98                         const char *base, int baselen,
99                         int stage, const char **match,
100                         read_tree_fn_t fn, void *context)
101 {
102         struct tree_desc desc;
103         struct name_entry entry;
104
105         if (parse_tree(tree))
106                 return -1;
107
108         init_tree_desc(&desc, tree->buffer, tree->size);
109
110         while (tree_entry(&desc, &entry)) {
111                 if (!match_tree_entry(base, baselen, entry.path, entry.mode, match))
112                         continue;
113
114                 switch (fn(entry.sha1, base, baselen, entry.path, entry.mode, stage, context)) {
115                 case 0:
116                         continue;
117                 case READ_TREE_RECURSIVE:
118                         break;
119                 default:
120                         return -1;
121                 }
122                 if (S_ISDIR(entry.mode)) {
123                         int retval;
124                         char *newbase;
125                         unsigned int pathlen = tree_entry_len(entry.path, entry.sha1);
126
127                         newbase = xmalloc(baselen + 1 + pathlen);
128                         memcpy(newbase, base, baselen);
129                         memcpy(newbase + baselen, entry.path, pathlen);
130                         newbase[baselen + pathlen] = '/';
131                         retval = read_tree_recursive(lookup_tree(entry.sha1),
132                                                      newbase,
133                                                      baselen + pathlen + 1,
134                                                      stage, match, fn, context);
135                         free(newbase);
136                         if (retval)
137                                 return -1;
138                         continue;
139                 } else if (S_ISGITLINK(entry.mode)) {
140                         int retval;
141                         struct strbuf path;
142                         unsigned int entrylen;
143                         struct commit *commit;
144
145                         entrylen = tree_entry_len(entry.path, entry.sha1);
146                         strbuf_init(&path, baselen + entrylen + 1);
147                         strbuf_add(&path, base, baselen);
148                         strbuf_add(&path, entry.path, entrylen);
149                         strbuf_addch(&path, '/');
150
151                         commit = lookup_commit(entry.sha1);
152                         if (!commit)
153                                 die("Commit %s in submodule path %s not found",
154                                     sha1_to_hex(entry.sha1), path.buf);
155
156                         if (parse_commit(commit))
157                                 die("Invalid commit %s in submodule path %s",
158                                     sha1_to_hex(entry.sha1), path.buf);
159
160                         retval = read_tree_recursive(commit->tree,
161                                                      path.buf, path.len,
162                                                      stage, match, fn, context);
163                         strbuf_release(&path);
164                         if (retval)
165                                 return -1;
166                         continue;
167                 }
168         }
169         return 0;
170 }
171
172 static int cmp_cache_name_compare(const void *a_, const void *b_)
173 {
174         const struct cache_entry *ce1, *ce2;
175
176         ce1 = *((const struct cache_entry **)a_);
177         ce2 = *((const struct cache_entry **)b_);
178         return cache_name_compare(ce1->name, ce1->ce_flags,
179                                   ce2->name, ce2->ce_flags);
180 }
181
182 int read_tree(struct tree *tree, int stage, const char **match)
183 {
184         read_tree_fn_t fn = NULL;
185         int i, err;
186
187         /*
188          * Currently the only existing callers of this function all
189          * call it with stage=1 and after making sure there is nothing
190          * at that stage; we could always use read_one_entry_quick().
191          *
192          * But when we decide to straighten out git-read-tree not to
193          * use unpack_trees() in some cases, this will probably start
194          * to matter.
195          */
196
197         /*
198          * See if we have cache entry at the stage.  If so,
199          * do it the original slow way, otherwise, append and then
200          * sort at the end.
201          */
202         for (i = 0; !fn && i < active_nr; i++) {
203                 struct cache_entry *ce = active_cache[i];
204                 if (ce_stage(ce) == stage)
205                         fn = read_one_entry;
206         }
207
208         if (!fn)
209                 fn = read_one_entry_quick;
210         err = read_tree_recursive(tree, "", 0, stage, match, fn, NULL);
211         if (fn == read_one_entry || err)
212                 return err;
213
214         /*
215          * Sort the cache entry -- we need to nuke the cache tree, though.
216          */
217         cache_tree_free(&active_cache_tree);
218         qsort(active_cache, active_nr, sizeof(active_cache[0]),
219               cmp_cache_name_compare);
220         return 0;
221 }
222
223 struct tree *lookup_tree(const unsigned char *sha1)
224 {
225         struct object *obj = lookup_object(sha1);
226         if (!obj)
227                 return create_object(sha1, OBJ_TREE, alloc_tree_node());
228         if (!obj->type)
229                 obj->type = OBJ_TREE;
230         if (obj->type != OBJ_TREE) {
231                 error("Object %s is a %s, not a tree",
232                       sha1_to_hex(sha1), typename(obj->type));
233                 return NULL;
234         }
235         return (struct tree *) obj;
236 }
237
238 int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)
239 {
240         if (item->object.parsed)
241                 return 0;
242         item->object.parsed = 1;
243         item->buffer = buffer;
244         item->size = size;
245
246         return 0;
247 }
248
249 int parse_tree(struct tree *item)
250 {
251          enum object_type type;
252          void *buffer;
253          unsigned long size;
254
255         if (item->object.parsed)
256                 return 0;
257         buffer = read_sha1_file(item->object.sha1, &type, &size);
258         if (!buffer)
259                 return error("Could not read %s",
260                              sha1_to_hex(item->object.sha1));
261         if (type != OBJ_TREE) {
262                 free(buffer);
263                 return error("Object %s not a tree",
264                              sha1_to_hex(item->object.sha1));
265         }
266         return parse_tree_buffer(item, buffer, size);
267 }
268
269 struct tree *parse_tree_indirect(const unsigned char *sha1)
270 {
271         struct object *obj = parse_object(sha1);
272         do {
273                 if (!obj)
274                         return NULL;
275                 if (obj->type == OBJ_TREE)
276                         return (struct tree *) obj;
277                 else if (obj->type == OBJ_COMMIT)
278                         obj = &(((struct commit *) obj)->tree->object);
279                 else if (obj->type == OBJ_TAG)
280                         obj = ((struct tag *) obj)->tagged;
281                 else
282                         return NULL;
283                 if (!obj->parsed)
284                         parse_object(obj->sha1);
285         } while (1);
286 }