update submodules: add submodule_move_head
[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_gently(const char *str, ssize_t len, int gentle)
37 {
38         int i;
39
40         if (len < 0)
41                 len = strlen(str);
42
43         for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
44                 if (!strncmp(str, object_type_strings[i], len) &&
45                     object_type_strings[i][len] == '\0')
46                         return i;
47
48         if (gentle)
49                 return -1;
50
51         die("invalid object type \"%s\"", str);
52 }
53
54 /*
55  * Return a numerical hash value between 0 and n-1 for the object with
56  * the specified sha1.  n must be a power of 2.  Please note that the
57  * return value is *not* consistent across computer architectures.
58  */
59 static unsigned int hash_obj(const unsigned char *sha1, unsigned int n)
60 {
61         return sha1hash(sha1) & (n - 1);
62 }
63
64 /*
65  * Insert obj into the hash table hash, which has length size (which
66  * must be a power of 2).  On collisions, simply overflow to the next
67  * empty bucket.
68  */
69 static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
70 {
71         unsigned int j = hash_obj(obj->oid.hash, size);
72
73         while (hash[j]) {
74                 j++;
75                 if (j >= size)
76                         j = 0;
77         }
78         hash[j] = obj;
79 }
80
81 /*
82  * Look up the record for the given sha1 in the hash map stored in
83  * obj_hash.  Return NULL if it was not found.
84  */
85 struct object *lookup_object(const unsigned char *sha1)
86 {
87         unsigned int i, first;
88         struct object *obj;
89
90         if (!obj_hash)
91                 return NULL;
92
93         first = i = hash_obj(sha1, obj_hash_size);
94         while ((obj = obj_hash[i]) != NULL) {
95                 if (!hashcmp(sha1, obj->oid.hash))
96                         break;
97                 i++;
98                 if (i == obj_hash_size)
99                         i = 0;
100         }
101         if (obj && i != first) {
102                 /*
103                  * Move object to where we started to look for it so
104                  * that we do not need to walk the hash table the next
105                  * time we look for it.
106                  */
107                 SWAP(obj_hash[i], obj_hash[first]);
108         }
109         return obj;
110 }
111
112 /*
113  * Increase the size of the hash map stored in obj_hash to the next
114  * power of 2 (but at least 32).  Copy the existing values to the new
115  * hash map.
116  */
117 static void grow_object_hash(void)
118 {
119         int i;
120         /*
121          * Note that this size must always be power-of-2 to match hash_obj
122          * above.
123          */
124         int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
125         struct object **new_hash;
126
127         new_hash = xcalloc(new_hash_size, sizeof(struct object *));
128         for (i = 0; i < obj_hash_size; i++) {
129                 struct object *obj = obj_hash[i];
130                 if (!obj)
131                         continue;
132                 insert_obj_hash(obj, new_hash, new_hash_size);
133         }
134         free(obj_hash);
135         obj_hash = new_hash;
136         obj_hash_size = new_hash_size;
137 }
138
139 void *create_object(const unsigned char *sha1, void *o)
140 {
141         struct object *obj = o;
142
143         obj->parsed = 0;
144         obj->used = 0;
145         obj->flags = 0;
146         hashcpy(obj->oid.hash, sha1);
147
148         if (obj_hash_size - 1 <= nr_objs * 2)
149                 grow_object_hash();
150
151         insert_obj_hash(obj, obj_hash, obj_hash_size);
152         nr_objs++;
153         return obj;
154 }
155
156 void *object_as_type(struct object *obj, enum object_type type, int quiet)
157 {
158         if (obj->type == type)
159                 return obj;
160         else if (obj->type == OBJ_NONE) {
161                 if (type == OBJ_COMMIT)
162                         ((struct commit *)obj)->index = alloc_commit_index();
163                 obj->type = type;
164                 return obj;
165         }
166         else {
167                 if (!quiet)
168                         error("object %s is a %s, not a %s",
169                               oid_to_hex(&obj->oid),
170                               typename(obj->type), typename(type));
171                 return NULL;
172         }
173 }
174
175 struct object *lookup_unknown_object(const unsigned char *sha1)
176 {
177         struct object *obj = lookup_object(sha1);
178         if (!obj)
179                 obj = create_object(sha1, alloc_object_node());
180         return obj;
181 }
182
183 struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
184 {
185         struct object *obj;
186         *eaten_p = 0;
187
188         obj = NULL;
189         if (type == OBJ_BLOB) {
190                 struct blob *blob = lookup_blob(sha1);
191                 if (blob) {
192                         if (parse_blob_buffer(blob, buffer, size))
193                                 return NULL;
194                         obj = &blob->object;
195                 }
196         } else if (type == OBJ_TREE) {
197                 struct tree *tree = lookup_tree(sha1);
198                 if (tree) {
199                         obj = &tree->object;
200                         if (!tree->buffer)
201                                 tree->object.parsed = 0;
202                         if (!tree->object.parsed) {
203                                 if (parse_tree_buffer(tree, buffer, size))
204                                         return NULL;
205                                 *eaten_p = 1;
206                         }
207                 }
208         } else if (type == OBJ_COMMIT) {
209                 struct commit *commit = lookup_commit(sha1);
210                 if (commit) {
211                         if (parse_commit_buffer(commit, buffer, size))
212                                 return NULL;
213                         if (!get_cached_commit_buffer(commit, NULL)) {
214                                 set_commit_buffer(commit, buffer, size);
215                                 *eaten_p = 1;
216                         }
217                         obj = &commit->object;
218                 }
219         } else if (type == OBJ_TAG) {
220                 struct tag *tag = lookup_tag(sha1);
221                 if (tag) {
222                         if (parse_tag_buffer(tag, buffer, size))
223                                return NULL;
224                         obj = &tag->object;
225                 }
226         } else {
227                 warning("object %s has unknown type id %d", sha1_to_hex(sha1), type);
228                 obj = NULL;
229         }
230         return obj;
231 }
232
233 struct object *parse_object_or_die(const unsigned char *sha1,
234                                    const char *name)
235 {
236         struct object *o = parse_object(sha1);
237         if (o)
238                 return o;
239
240         die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));
241 }
242
243 struct object *parse_object(const unsigned char *sha1)
244 {
245         unsigned long size;
246         enum object_type type;
247         int eaten;
248         const unsigned char *repl = lookup_replace_object(sha1);
249         void *buffer;
250         struct object *obj;
251
252         obj = lookup_object(sha1);
253         if (obj && obj->parsed)
254                 return obj;
255
256         if ((obj && obj->type == OBJ_BLOB) ||
257             (!obj && has_sha1_file(sha1) &&
258              sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
259                 if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
260                         error("sha1 mismatch %s", sha1_to_hex(repl));
261                         return NULL;
262                 }
263                 parse_blob_buffer(lookup_blob(sha1), NULL, 0);
264                 return lookup_object(sha1);
265         }
266
267         buffer = read_sha1_file(sha1, &type, &size);
268         if (buffer) {
269                 if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
270                         free(buffer);
271                         error("sha1 mismatch %s", sha1_to_hex(repl));
272                         return NULL;
273                 }
274
275                 obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
276                 if (!eaten)
277                         free(buffer);
278                 return obj;
279         }
280         return NULL;
281 }
282
283 struct object_list *object_list_insert(struct object *item,
284                                        struct object_list **list_p)
285 {
286         struct object_list *new_list = xmalloc(sizeof(struct object_list));
287         new_list->item = item;
288         new_list->next = *list_p;
289         *list_p = new_list;
290         return new_list;
291 }
292
293 int object_list_contains(struct object_list *list, struct object *obj)
294 {
295         while (list) {
296                 if (list->item == obj)
297                         return 1;
298                 list = list->next;
299         }
300         return 0;
301 }
302
303 /*
304  * A zero-length string to which object_array_entry::name can be
305  * initialized without requiring a malloc/free.
306  */
307 static char object_array_slopbuf[1];
308
309 void add_object_array_with_path(struct object *obj, const char *name,
310                                 struct object_array *array,
311                                 unsigned mode, const char *path)
312 {
313         unsigned nr = array->nr;
314         unsigned alloc = array->alloc;
315         struct object_array_entry *objects = array->objects;
316         struct object_array_entry *entry;
317
318         if (nr >= alloc) {
319                 alloc = (alloc + 32) * 2;
320                 REALLOC_ARRAY(objects, alloc);
321                 array->alloc = alloc;
322                 array->objects = objects;
323         }
324         entry = &objects[nr];
325         entry->item = obj;
326         if (!name)
327                 entry->name = NULL;
328         else if (!*name)
329                 /* Use our own empty string instead of allocating one: */
330                 entry->name = object_array_slopbuf;
331         else
332                 entry->name = xstrdup(name);
333         entry->mode = mode;
334         if (path)
335                 entry->path = xstrdup(path);
336         else
337                 entry->path = NULL;
338         array->nr = ++nr;
339 }
340
341 void add_object_array(struct object *obj, const char *name, struct object_array *array)
342 {
343         add_object_array_with_path(obj, name, array, S_IFINVALID, NULL);
344 }
345
346 /*
347  * Free all memory associated with an entry; the result is
348  * in an unspecified state and should not be examined.
349  */
350 static void object_array_release_entry(struct object_array_entry *ent)
351 {
352         if (ent->name != object_array_slopbuf)
353                 free(ent->name);
354         free(ent->path);
355 }
356
357 void object_array_filter(struct object_array *array,
358                          object_array_each_func_t want, void *cb_data)
359 {
360         unsigned nr = array->nr, src, dst;
361         struct object_array_entry *objects = array->objects;
362
363         for (src = dst = 0; src < nr; src++) {
364                 if (want(&objects[src], cb_data)) {
365                         if (src != dst)
366                                 objects[dst] = objects[src];
367                         dst++;
368                 } else {
369                         object_array_release_entry(&objects[src]);
370                 }
371         }
372         array->nr = dst;
373 }
374
375 void object_array_clear(struct object_array *array)
376 {
377         int i;
378         for (i = 0; i < array->nr; i++)
379                 object_array_release_entry(&array->objects[i]);
380         free(array->objects);
381         array->objects = NULL;
382         array->nr = array->alloc = 0;
383 }
384
385 /*
386  * Return true iff array already contains an entry with name.
387  */
388 static int contains_name(struct object_array *array, const char *name)
389 {
390         unsigned nr = array->nr, i;
391         struct object_array_entry *object = array->objects;
392
393         for (i = 0; i < nr; i++, object++)
394                 if (!strcmp(object->name, name))
395                         return 1;
396         return 0;
397 }
398
399 void object_array_remove_duplicates(struct object_array *array)
400 {
401         unsigned nr = array->nr, src;
402         struct object_array_entry *objects = array->objects;
403
404         array->nr = 0;
405         for (src = 0; src < nr; src++) {
406                 if (!contains_name(array, objects[src].name)) {
407                         if (src != array->nr)
408                                 objects[array->nr] = objects[src];
409                         array->nr++;
410                 } else {
411                         object_array_release_entry(&objects[src]);
412                 }
413         }
414 }
415
416 void clear_object_flags(unsigned flags)
417 {
418         int i;
419
420         for (i=0; i < obj_hash_size; i++) {
421                 struct object *obj = obj_hash[i];
422                 if (obj)
423                         obj->flags &= ~flags;
424         }
425 }