Merge branch 'jk/fsck-exit-code-fix' into maint
[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, void *o)
134 {
135         struct object *obj = o;
136
137         obj->parsed = 0;
138         obj->used = 0;
139         obj->flags = 0;
140         hashcpy(obj->sha1, sha1);
141
142         if (obj_hash_size - 1 <= nr_objs * 2)
143                 grow_object_hash();
144
145         insert_obj_hash(obj, obj_hash, obj_hash_size);
146         nr_objs++;
147         return obj;
148 }
149
150 void *object_as_type(struct object *obj, enum object_type type, int quiet)
151 {
152         if (obj->type == type)
153                 return obj;
154         else if (obj->type == OBJ_NONE) {
155                 if (type == OBJ_COMMIT)
156                         ((struct commit *)obj)->index = alloc_commit_index();
157                 obj->type = type;
158                 return obj;
159         }
160         else {
161                 if (!quiet)
162                         error("object %s is a %s, not a %s",
163                               sha1_to_hex(obj->sha1),
164                               typename(obj->type), typename(type));
165                 return NULL;
166         }
167 }
168
169 struct object *lookup_unknown_object(const unsigned char *sha1)
170 {
171         struct object *obj = lookup_object(sha1);
172         if (!obj)
173                 obj = create_object(sha1, alloc_object_node());
174         return obj;
175 }
176
177 struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
178 {
179         struct object *obj;
180         *eaten_p = 0;
181
182         obj = NULL;
183         if (type == OBJ_BLOB) {
184                 struct blob *blob = lookup_blob(sha1);
185                 if (blob) {
186                         if (parse_blob_buffer(blob, buffer, size))
187                                 return NULL;
188                         obj = &blob->object;
189                 }
190         } else if (type == OBJ_TREE) {
191                 struct tree *tree = lookup_tree(sha1);
192                 if (tree) {
193                         obj = &tree->object;
194                         if (!tree->buffer)
195                                 tree->object.parsed = 0;
196                         if (!tree->object.parsed) {
197                                 if (parse_tree_buffer(tree, buffer, size))
198                                         return NULL;
199                                 *eaten_p = 1;
200                         }
201                 }
202         } else if (type == OBJ_COMMIT) {
203                 struct commit *commit = lookup_commit(sha1);
204                 if (commit) {
205                         if (parse_commit_buffer(commit, buffer, size))
206                                 return NULL;
207                         if (!get_cached_commit_buffer(commit, NULL)) {
208                                 set_commit_buffer(commit, buffer, size);
209                                 *eaten_p = 1;
210                         }
211                         obj = &commit->object;
212                 }
213         } else if (type == OBJ_TAG) {
214                 struct tag *tag = lookup_tag(sha1);
215                 if (tag) {
216                         if (parse_tag_buffer(tag, buffer, size))
217                                return NULL;
218                         obj = &tag->object;
219                 }
220         } else {
221                 warning("object %s has unknown type id %d", sha1_to_hex(sha1), type);
222                 obj = NULL;
223         }
224         return obj;
225 }
226
227 struct object *parse_object_or_die(const unsigned char *sha1,
228                                    const char *name)
229 {
230         struct object *o = parse_object(sha1);
231         if (o)
232                 return o;
233
234         die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));
235 }
236
237 struct object *parse_object(const unsigned char *sha1)
238 {
239         unsigned long size;
240         enum object_type type;
241         int eaten;
242         const unsigned char *repl = lookup_replace_object(sha1);
243         void *buffer;
244         struct object *obj;
245
246         obj = lookup_object(sha1);
247         if (obj && obj->parsed)
248                 return obj;
249
250         if ((obj && obj->type == OBJ_BLOB) ||
251             (!obj && has_sha1_file(sha1) &&
252              sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
253                 if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
254                         error("sha1 mismatch %s", sha1_to_hex(repl));
255                         return NULL;
256                 }
257                 parse_blob_buffer(lookup_blob(sha1), NULL, 0);
258                 return lookup_object(sha1);
259         }
260
261         buffer = read_sha1_file(sha1, &type, &size);
262         if (buffer) {
263                 if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
264                         free(buffer);
265                         error("sha1 mismatch %s", sha1_to_hex(repl));
266                         return NULL;
267                 }
268
269                 obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
270                 if (!eaten)
271                         free(buffer);
272                 return obj;
273         }
274         return NULL;
275 }
276
277 struct object_list *object_list_insert(struct object *item,
278                                        struct object_list **list_p)
279 {
280         struct object_list *new_list = xmalloc(sizeof(struct object_list));
281         new_list->item = item;
282         new_list->next = *list_p;
283         *list_p = new_list;
284         return new_list;
285 }
286
287 int object_list_contains(struct object_list *list, struct object *obj)
288 {
289         while (list) {
290                 if (list->item == obj)
291                         return 1;
292                 list = list->next;
293         }
294         return 0;
295 }
296
297 /*
298  * A zero-length string to which object_array_entry::name can be
299  * initialized without requiring a malloc/free.
300  */
301 static char object_array_slopbuf[1];
302
303 static void add_object_array_with_mode_context(struct object *obj, const char *name,
304                                                struct object_array *array,
305                                                unsigned mode,
306                                                struct object_context *context)
307 {
308         unsigned nr = array->nr;
309         unsigned alloc = array->alloc;
310         struct object_array_entry *objects = array->objects;
311         struct object_array_entry *entry;
312
313         if (nr >= alloc) {
314                 alloc = (alloc + 32) * 2;
315                 objects = xrealloc(objects, alloc * sizeof(*objects));
316                 array->alloc = alloc;
317                 array->objects = objects;
318         }
319         entry = &objects[nr];
320         entry->item = obj;
321         if (!name)
322                 entry->name = NULL;
323         else if (!*name)
324                 /* Use our own empty string instead of allocating one: */
325                 entry->name = object_array_slopbuf;
326         else
327                 entry->name = xstrdup(name);
328         entry->mode = mode;
329         entry->context = context;
330         array->nr = ++nr;
331 }
332
333 void add_object_array(struct object *obj, const char *name, struct object_array *array)
334 {
335         add_object_array_with_mode(obj, name, array, S_IFINVALID);
336 }
337
338 void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode)
339 {
340         add_object_array_with_mode_context(obj, name, array, mode, NULL);
341 }
342
343 void add_object_array_with_context(struct object *obj, const char *name, struct object_array *array, struct object_context *context)
344 {
345         if (context)
346                 add_object_array_with_mode_context(obj, name, array, context->mode, context);
347         else
348                 add_object_array_with_mode_context(obj, name, array, S_IFINVALID, context);
349 }
350
351 void object_array_filter(struct object_array *array,
352                          object_array_each_func_t want, void *cb_data)
353 {
354         unsigned nr = array->nr, src, dst;
355         struct object_array_entry *objects = array->objects;
356
357         for (src = dst = 0; src < nr; src++) {
358                 if (want(&objects[src], cb_data)) {
359                         if (src != dst)
360                                 objects[dst] = objects[src];
361                         dst++;
362                 } else {
363                         if (objects[src].name != object_array_slopbuf)
364                                 free(objects[src].name);
365                 }
366         }
367         array->nr = dst;
368 }
369
370 /*
371  * Return true iff array already contains an entry with name.
372  */
373 static int contains_name(struct object_array *array, const char *name)
374 {
375         unsigned nr = array->nr, i;
376         struct object_array_entry *object = array->objects;
377
378         for (i = 0; i < nr; i++, object++)
379                 if (!strcmp(object->name, name))
380                         return 1;
381         return 0;
382 }
383
384 void object_array_remove_duplicates(struct object_array *array)
385 {
386         unsigned nr = array->nr, src;
387         struct object_array_entry *objects = array->objects;
388
389         array->nr = 0;
390         for (src = 0; src < nr; src++) {
391                 if (!contains_name(array, objects[src].name)) {
392                         if (src != array->nr)
393                                 objects[array->nr] = objects[src];
394                         array->nr++;
395                 } else {
396                         if (objects[src].name != object_array_slopbuf)
397                                 free(objects[src].name);
398                 }
399         }
400 }
401
402 void clear_object_flags(unsigned flags)
403 {
404         int i;
405
406         for (i=0; i < obj_hash_size; i++) {
407                 struct object *obj = obj_hash[i];
408                 if (obj)
409                         obj->flags &= ~flags;
410         }
411 }