Merge branch 'kb/avoid-fchmod-for-now'
[git] / object.c
1 #include "cache.h"
2 #include "object.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "commit.h"
6 #include "tag.h"
7
8 static struct object **obj_hash;
9 static int nr_objs, obj_hash_size;
10
11 unsigned int get_max_object_index(void)
12 {
13         return obj_hash_size;
14 }
15
16 struct object *get_indexed_object(unsigned int idx)
17 {
18         return obj_hash[idx];
19 }
20
21 static const char *object_type_strings[] = {
22         NULL,           /* OBJ_NONE = 0 */
23         "commit",       /* OBJ_COMMIT = 1 */
24         "tree",         /* OBJ_TREE = 2 */
25         "blob",         /* OBJ_BLOB = 3 */
26         "tag",          /* OBJ_TAG = 4 */
27 };
28
29 const char *typename(unsigned int type)
30 {
31         if (type >= ARRAY_SIZE(object_type_strings))
32                 return NULL;
33         return object_type_strings[type];
34 }
35
36 int type_from_string(const char *str)
37 {
38         int i;
39
40         for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
41                 if (!strcmp(str, object_type_strings[i]))
42                         return i;
43         die("invalid object type \"%s\"", str);
44 }
45
46 /*
47  * Return a numerical hash value between 0 and n-1 for the object with
48  * the specified sha1.  n must be a power of 2.  Please note that the
49  * return value is *not* consistent across computer architectures.
50  */
51 static unsigned int hash_obj(const unsigned char *sha1, unsigned int n)
52 {
53         return sha1hash(sha1) & (n - 1);
54 }
55
56 /*
57  * Insert obj into the hash table hash, which has length size (which
58  * must be a power of 2).  On collisions, simply overflow to the next
59  * empty bucket.
60  */
61 static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
62 {
63         unsigned int j = hash_obj(obj->sha1, size);
64
65         while (hash[j]) {
66                 j++;
67                 if (j >= size)
68                         j = 0;
69         }
70         hash[j] = obj;
71 }
72
73 /*
74  * Look up the record for the given sha1 in the hash map stored in
75  * obj_hash.  Return NULL if it was not found.
76  */
77 struct object *lookup_object(const unsigned char *sha1)
78 {
79         unsigned int i, first;
80         struct object *obj;
81
82         if (!obj_hash)
83                 return NULL;
84
85         first = i = hash_obj(sha1, obj_hash_size);
86         while ((obj = obj_hash[i]) != NULL) {
87                 if (!hashcmp(sha1, obj->sha1))
88                         break;
89                 i++;
90                 if (i == obj_hash_size)
91                         i = 0;
92         }
93         if (obj && i != first) {
94                 /*
95                  * Move object to where we started to look for it so
96                  * that we do not need to walk the hash table the next
97                  * time we look for it.
98                  */
99                 struct object *tmp = obj_hash[i];
100                 obj_hash[i] = obj_hash[first];
101                 obj_hash[first] = tmp;
102         }
103         return obj;
104 }
105
106 /*
107  * Increase the size of the hash map stored in obj_hash to the next
108  * power of 2 (but at least 32).  Copy the existing values to the new
109  * hash map.
110  */
111 static void grow_object_hash(void)
112 {
113         int i;
114         /*
115          * Note that this size must always be power-of-2 to match hash_obj
116          * above.
117          */
118         int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
119         struct object **new_hash;
120
121         new_hash = xcalloc(new_hash_size, sizeof(struct object *));
122         for (i = 0; i < obj_hash_size; i++) {
123                 struct object *obj = obj_hash[i];
124                 if (!obj)
125                         continue;
126                 insert_obj_hash(obj, new_hash, new_hash_size);
127         }
128         free(obj_hash);
129         obj_hash = new_hash;
130         obj_hash_size = new_hash_size;
131 }
132
133 void *create_object(const unsigned char *sha1, int type, void *o)
134 {
135         struct object *obj = o;
136
137         obj->parsed = 0;
138         obj->used = 0;
139         obj->type = type;
140         obj->flags = 0;
141         hashcpy(obj->sha1, sha1);
142
143         if (obj_hash_size - 1 <= nr_objs * 2)
144                 grow_object_hash();
145
146         insert_obj_hash(obj, obj_hash, obj_hash_size);
147         nr_objs++;
148         return obj;
149 }
150
151 struct object *lookup_unknown_object(const unsigned char *sha1)
152 {
153         struct object *obj = lookup_object(sha1);
154         if (!obj)
155                 obj = create_object(sha1, OBJ_NONE, alloc_object_node());
156         return obj;
157 }
158
159 struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
160 {
161         struct object *obj;
162         *eaten_p = 0;
163
164         obj = NULL;
165         if (type == OBJ_BLOB) {
166                 struct blob *blob = lookup_blob(sha1);
167                 if (blob) {
168                         if (parse_blob_buffer(blob, buffer, size))
169                                 return NULL;
170                         obj = &blob->object;
171                 }
172         } else if (type == OBJ_TREE) {
173                 struct tree *tree = lookup_tree(sha1);
174                 if (tree) {
175                         obj = &tree->object;
176                         if (!tree->buffer)
177                                 tree->object.parsed = 0;
178                         if (!tree->object.parsed) {
179                                 if (parse_tree_buffer(tree, buffer, size))
180                                         return NULL;
181                                 *eaten_p = 1;
182                         }
183                 }
184         } else if (type == OBJ_COMMIT) {
185                 struct commit *commit = lookup_commit(sha1);
186                 if (commit) {
187                         if (parse_commit_buffer(commit, buffer, size))
188                                 return NULL;
189                         if (!get_cached_commit_buffer(commit, NULL)) {
190                                 set_commit_buffer(commit, buffer, size);
191                                 *eaten_p = 1;
192                         }
193                         obj = &commit->object;
194                 }
195         } else if (type == OBJ_TAG) {
196                 struct tag *tag = lookup_tag(sha1);
197                 if (tag) {
198                         if (parse_tag_buffer(tag, buffer, size))
199                                return NULL;
200                         obj = &tag->object;
201                 }
202         } else {
203                 warning("object %s has unknown type id %d", sha1_to_hex(sha1), type);
204                 obj = NULL;
205         }
206         if (obj && obj->type == OBJ_NONE)
207                 obj->type = type;
208         return obj;
209 }
210
211 struct object *parse_object_or_die(const unsigned char *sha1,
212                                    const char *name)
213 {
214         struct object *o = parse_object(sha1);
215         if (o)
216                 return o;
217
218         die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));
219 }
220
221 struct object *parse_object(const unsigned char *sha1)
222 {
223         unsigned long size;
224         enum object_type type;
225         int eaten;
226         const unsigned char *repl = lookup_replace_object(sha1);
227         void *buffer;
228         struct object *obj;
229
230         obj = lookup_object(sha1);
231         if (obj && obj->parsed)
232                 return obj;
233
234         if ((obj && obj->type == OBJ_BLOB) ||
235             (!obj && has_sha1_file(sha1) &&
236              sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
237                 if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
238                         error("sha1 mismatch %s", sha1_to_hex(repl));
239                         return NULL;
240                 }
241                 parse_blob_buffer(lookup_blob(sha1), NULL, 0);
242                 return lookup_object(sha1);
243         }
244
245         buffer = read_sha1_file(sha1, &type, &size);
246         if (buffer) {
247                 if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
248                         free(buffer);
249                         error("sha1 mismatch %s", sha1_to_hex(repl));
250                         return NULL;
251                 }
252
253                 obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
254                 if (!eaten)
255                         free(buffer);
256                 return obj;
257         }
258         return NULL;
259 }
260
261 struct object_list *object_list_insert(struct object *item,
262                                        struct object_list **list_p)
263 {
264         struct object_list *new_list = xmalloc(sizeof(struct object_list));
265         new_list->item = item;
266         new_list->next = *list_p;
267         *list_p = new_list;
268         return new_list;
269 }
270
271 int object_list_contains(struct object_list *list, struct object *obj)
272 {
273         while (list) {
274                 if (list->item == obj)
275                         return 1;
276                 list = list->next;
277         }
278         return 0;
279 }
280
281 /*
282  * A zero-length string to which object_array_entry::name can be
283  * initialized without requiring a malloc/free.
284  */
285 static char object_array_slopbuf[1];
286
287 static void add_object_array_with_mode_context(struct object *obj, const char *name,
288                                                struct object_array *array,
289                                                unsigned mode,
290                                                struct object_context *context)
291 {
292         unsigned nr = array->nr;
293         unsigned alloc = array->alloc;
294         struct object_array_entry *objects = array->objects;
295         struct object_array_entry *entry;
296
297         if (nr >= alloc) {
298                 alloc = (alloc + 32) * 2;
299                 objects = xrealloc(objects, alloc * sizeof(*objects));
300                 array->alloc = alloc;
301                 array->objects = objects;
302         }
303         entry = &objects[nr];
304         entry->item = obj;
305         if (!name)
306                 entry->name = NULL;
307         else if (!*name)
308                 /* Use our own empty string instead of allocating one: */
309                 entry->name = object_array_slopbuf;
310         else
311                 entry->name = xstrdup(name);
312         entry->mode = mode;
313         entry->context = context;
314         array->nr = ++nr;
315 }
316
317 void add_object_array(struct object *obj, const char *name, struct object_array *array)
318 {
319         add_object_array_with_mode(obj, name, array, S_IFINVALID);
320 }
321
322 void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode)
323 {
324         add_object_array_with_mode_context(obj, name, array, mode, NULL);
325 }
326
327 void add_object_array_with_context(struct object *obj, const char *name, struct object_array *array, struct object_context *context)
328 {
329         if (context)
330                 add_object_array_with_mode_context(obj, name, array, context->mode, context);
331         else
332                 add_object_array_with_mode_context(obj, name, array, S_IFINVALID, context);
333 }
334
335 void object_array_filter(struct object_array *array,
336                          object_array_each_func_t want, void *cb_data)
337 {
338         unsigned nr = array->nr, src, dst;
339         struct object_array_entry *objects = array->objects;
340
341         for (src = dst = 0; src < nr; src++) {
342                 if (want(&objects[src], cb_data)) {
343                         if (src != dst)
344                                 objects[dst] = objects[src];
345                         dst++;
346                 } else {
347                         if (objects[src].name != object_array_slopbuf)
348                                 free(objects[src].name);
349                 }
350         }
351         array->nr = dst;
352 }
353
354 /*
355  * Return true iff array already contains an entry with name.
356  */
357 static int contains_name(struct object_array *array, const char *name)
358 {
359         unsigned nr = array->nr, i;
360         struct object_array_entry *object = array->objects;
361
362         for (i = 0; i < nr; i++, object++)
363                 if (!strcmp(object->name, name))
364                         return 1;
365         return 0;
366 }
367
368 void object_array_remove_duplicates(struct object_array *array)
369 {
370         unsigned nr = array->nr, src;
371         struct object_array_entry *objects = array->objects;
372
373         array->nr = 0;
374         for (src = 0; src < nr; src++) {
375                 if (!contains_name(array, objects[src].name)) {
376                         if (src != array->nr)
377                                 objects[array->nr] = objects[src];
378                         array->nr++;
379                 } else {
380                         if (objects[src].name != object_array_slopbuf)
381                                 free(objects[src].name);
382                 }
383         }
384 }
385
386 void clear_object_flags(unsigned flags)
387 {
388         int i;
389
390         for (i=0; i < obj_hash_size; i++) {
391                 struct object *obj = obj_hash[i];
392                 if (obj)
393                         obj->flags &= ~flags;
394         }
395 }