aboutsummaryrefslogtreecommitdiff
path: root/object.c
blob: b2319f62468c76134e84c157c2035654b38e17fc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
#include "cache.h"
#include "object.h"
#include "blob.h"
#include "tree.h"
#include "commit.h"
#include "tag.h"

static struct object **obj_hash;
static int nr_objs, obj_hash_size;

unsigned int get_max_object_index(void)
{
	return obj_hash_size;
}

struct object *get_indexed_object(unsigned int idx)
{
	return obj_hash[idx];
}

static const char *object_type_strings[] = {
	NULL,		/* OBJ_NONE = 0 */
	"commit",	/* OBJ_COMMIT = 1 */
	"tree",		/* OBJ_TREE = 2 */
	"blob",		/* OBJ_BLOB = 3 */
	"tag",		/* OBJ_TAG = 4 */
};

const char *typename(unsigned int type)
{
	if (type >= ARRAY_SIZE(object_type_strings))
		return NULL;
	return object_type_strings[type];
}

int type_from_string(const char *str)
{
	int i;

	for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
		if (!strcmp(str, object_type_strings[i]))
			return i;
	die("invalid object type \"%s\"", str);
}

/*
 * Return a numerical hash value between 0 and n-1 for the object with
 * the specified sha1.  n must be a power of 2.  Please note that the
 * return value is *not* consistent across computer architectures.
 */
static unsigned int hash_obj(const unsigned char *sha1, unsigned int n)
{
	unsigned int hash;

	/*
	 * Since the sha1 is essentially random, we just take the
	 * required number of bits directly from the first
	 * sizeof(unsigned int) bytes of sha1.  First we have to copy
	 * the bytes into a properly aligned integer.  If we cared
	 * about getting consistent results across architectures, we
	 * would have to call ntohl() here, too.
	 */
	memcpy(&hash, sha1, sizeof(unsigned int));
	return hash & (n - 1);
}

/*
 * Insert obj into the hash table hash, which has length size (which
 * must be a power of 2).  On collisions, simply overflow to the next
 * empty bucket.
 */
static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
{
	unsigned int j = hash_obj(obj->sha1, size);

	while (hash[j]) {
		j++;
		if (j >= size)
			j = 0;
	}
	hash[j] = obj;
}

/*
 * Look up the record for the given sha1 in the hash map stored in
 * obj_hash.  Return NULL if it was not found.
 */
struct object *lookup_object(const unsigned char *sha1)
{
	unsigned int i, first;
	struct object *obj;

	if (!obj_hash)
		return NULL;

	first = i = hash_obj(sha1, obj_hash_size);
	while ((obj = obj_hash[i]) != NULL) {
		if (!hashcmp(sha1, obj->sha1))
			break;
		i++;
		if (i == obj_hash_size)
			i = 0;
	}
	if (obj && i != first) {
		/*
		 * Move object to where we started to look for it so
		 * that we do not need to walk the hash table the next
		 * time we look for it.
		 */
		struct object *tmp = obj_hash[i];
		obj_hash[i] = obj_hash[first];
		obj_hash[first] = tmp;
	}
	return obj;
}

/*
 * Increase the size of the hash map stored in obj_hash to the next
 * power of 2 (but at least 32).  Copy the existing values to the new
 * hash map.
 */
static void grow_object_hash(void)
{
	int i;
	/*
	 * Note that this size must always be power-of-2 to match hash_obj
	 * above.
	 */
	int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
	struct object **new_hash;

	new_hash = xcalloc(new_hash_size, sizeof(struct object *));
	for (i = 0; i < obj_hash_size; i++) {
		struct object *obj = obj_hash[i];
		if (!obj)
			continue;
		insert_obj_hash(obj, new_hash, new_hash_size);
	}
	free(obj_hash);
	obj_hash = new_hash;
	obj_hash_size = new_hash_size;
}

void *create_object(const unsigned char *sha1, void *o)
{
	struct object *obj = o;

	obj->parsed = 0;
	obj->used = 0;
	obj->flags = 0;
	hashcpy(obj->sha1, sha1);

	if (obj_hash_size - 1 <= nr_objs * 2)
		grow_object_hash();

	insert_obj_hash(obj, obj_hash, obj_hash_size);
	nr_objs++;
	return obj;
}

void *object_as_type(struct object *obj, enum object_type type, int quiet)
{
	if (obj->type == type)
		return obj;
	else if (obj->type == OBJ_NONE) {
		obj->type = type;
		return obj;
	}
	else {
		if (!quiet)
			error("object %s is a %s, not a %s",
			      sha1_to_hex(obj->sha1),
			      typename(obj->type), typename(type));
		return NULL;
	}
}

struct object *lookup_unknown_object(const unsigned char *sha1)
{
	struct object *obj = lookup_object(sha1);
	if (!obj)
		obj = create_object(sha1, alloc_object_node());
	return obj;
}

struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
{
	struct object *obj;
	*eaten_p = 0;

	obj = NULL;
	if (type == OBJ_BLOB) {
		struct blob *blob = lookup_blob(sha1);
		if (blob) {
			if (parse_blob_buffer(blob, buffer, size))
				return NULL;
			obj = &blob->object;
		}
	} else if (type == OBJ_TREE) {
		struct tree *tree = lookup_tree(sha1);
		if (tree) {
			obj = &tree->object;
			if (!tree->buffer)
				tree->object.parsed = 0;
			if (!tree->object.parsed) {
				if (parse_tree_buffer(tree, buffer, size))
					return NULL;
				*eaten_p = 1;
			}
		}
	} else if (type == OBJ_COMMIT) {
		struct commit *commit = lookup_commit(sha1);
		if (commit) {
			if (parse_commit_buffer(commit, buffer, size))
				return NULL;
			if (!get_cached_commit_buffer(commit, NULL)) {
				set_commit_buffer(commit, buffer, size);
				*eaten_p = 1;
			}
			obj = &commit->object;
		}
	} else if (type == OBJ_TAG) {
		struct tag *tag = lookup_tag(sha1);
		if (tag) {
			if (parse_tag_buffer(tag, buffer, size))
			       return NULL;
			obj = &tag->object;
		}
	} else {
		warning("object %s has unknown type id %d", sha1_to_hex(sha1), type);
		obj = NULL;
	}
	return obj;
}

struct object *parse_object_or_die(const unsigned char *sha1,
				   const char *name)
{
	struct object *o = parse_object(sha1);
	if (o)
		return o;

	die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));
}

struct object *parse_object(const unsigned char *sha1)
{
	unsigned long size;
	enum object_type type;
	int eaten;
	const unsigned char *repl = lookup_replace_object(sha1);
	void *buffer;
	struct object *obj;

	obj = lookup_object(sha1);
	if (obj && obj->parsed)
		return obj;

	if ((obj && obj->type == OBJ_BLOB) ||
	    (!obj && has_sha1_file(sha1) &&
	     sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
		if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
			error("sha1 mismatch %s", sha1_to_hex(repl));
			return NULL;
		}
		parse_blob_buffer(lookup_blob(sha1), NULL, 0);
		return lookup_object(sha1);
	}

	buffer = read_sha1_file(sha1, &type, &size);
	if (buffer) {
		if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
			free(buffer);
			error("sha1 mismatch %s", sha1_to_hex(repl));
			return NULL;
		}

		obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
		if (!eaten)
			free(buffer);
		return obj;
	}
	return NULL;
}

struct object_list *object_list_insert(struct object *item,
				       struct object_list **list_p)
{
	struct object_list *new_list = xmalloc(sizeof(struct object_list));
	new_list->item = item;
	new_list->next = *list_p;
	*list_p = new_list;
	return new_list;
}

int object_list_contains(struct object_list *list, struct object *obj)
{
	while (list) {
		if (list->item == obj)
			return 1;
		list = list->next;
	}
	return 0;
}

/*
 * A zero-length string to which object_array_entry::name can be
 * initialized without requiring a malloc/free.
 */
static char object_array_slopbuf[1];

static void add_object_array_with_mode_context(struct object *obj, const char *name,
					       struct object_array *array,
					       unsigned mode,
					       struct object_context *context)
{
	unsigned nr = array->nr;
	unsigned alloc = array->alloc;
	struct object_array_entry *objects = array->objects;
	struct object_array_entry *entry;

	if (nr >= alloc) {
		alloc = (alloc + 32) * 2;
		objects = xrealloc(objects, alloc * sizeof(*objects));
		array->alloc = alloc;
		array->objects = objects;
	}
	entry = &objects[nr];
	entry->item = obj;
	if (!name)
		entry->name = NULL;
	else if (!*name)
		/* Use our own empty string instead of allocating one: */
		entry->name = object_array_slopbuf;
	else
		entry->name = xstrdup(name);
	entry->mode = mode;
	entry->context = context;
	array->nr = ++nr;
}

void add_object_array(struct object *obj, const char *name, struct object_array *array)
{
	add_object_array_with_mode(obj, name, array, S_IFINVALID);
}

void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode)
{
	add_object_array_with_mode_context(obj, name, array, mode, NULL);
}

void add_object_array_with_context(struct object *obj, const char *name, struct object_array *array, struct object_context *context)
{
	if (context)
		add_object_array_with_mode_context(obj, name, array, context->mode, context);
	else
		add_object_array_with_mode_context(obj, name, array, S_IFINVALID, context);
}

void object_array_filter(struct object_array *array,
			 object_array_each_func_t want, void *cb_data)
{
	unsigned nr = array->nr, src, dst;
	struct object_array_entry *objects = array->objects;

	for (src = dst = 0; src < nr; src++) {
		if (want(&objects[src], cb_data)) {
			if (src != dst)
				objects[dst] = objects[src];
			dst++;
		} else {
			if (objects[src].name != object_array_slopbuf)
				free(objects[src].name);
		}
	}
	array->nr = dst;
}

/*
 * Return true iff array already contains an entry with name.
 */
static int contains_name(struct object_array *array, const char *name)
{
	unsigned nr = array->nr, i;
	struct object_array_entry *object = array->objects;

	for (i = 0; i < nr; i++, object++)
		if (!strcmp(object->name, name))
			return 1;
	return 0;
}

void object_array_remove_duplicates(struct object_array *array)
{
	unsigned nr = array->nr, src;
	struct object_array_entry *objects = array->objects;

	array->nr = 0;
	for (src = 0; src < nr; src++) {
		if (!contains_name(array, objects[src].name)) {
			if (src != array->nr)
				objects[array->nr] = objects[src];
			array->nr++;
		} else {
			if (objects[src].name != object_array_slopbuf)
				free(objects[src].name);
		}
	}
}

void clear_object_flags(unsigned flags)
{
	int i;

	for (i=0; i < obj_hash_size; i++) {
		struct object *obj = obj_hash[i];
		if (obj)
			obj->flags &= ~flags;
	}
}