xref: /netbsd-src/common/lib/libprop/prop_array.c (revision 4b71a66d0f279143147d63ebfcfd8a59499a3684)
1 /*	$NetBSD: prop_array.c,v 1.18 2008/05/24 14:32:48 yamt Exp $	*/
2 
3 /*-
4  * Copyright (c) 2006, 2007 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <prop/prop_array.h>
33 #include "prop_object_impl.h"
34 
35 #if !defined(_KERNEL) && !defined(_STANDALONE)
36 #include <errno.h>
37 #endif
38 
39 struct _prop_array {
40 	struct _prop_object	pa_obj;
41 	_PROP_RWLOCK_DECL(pa_rwlock)
42 	prop_object_t *		pa_array;
43 	unsigned int		pa_capacity;
44 	unsigned int		pa_count;
45 	int			pa_flags;
46 
47 	uint32_t		pa_version;
48 };
49 
50 #define	PA_F_IMMUTABLE		0x01	/* array is immutable */
51 
52 _PROP_POOL_INIT(_prop_array_pool, sizeof(struct _prop_array), "proparay")
53 _PROP_MALLOC_DEFINE(M_PROP_ARRAY, "prop array",
54 		    "property array container object")
55 
56 static int		_prop_array_free(prop_stack_t, prop_object_t *);
57 static void		_prop_array_emergency_free(prop_object_t);
58 static bool	_prop_array_externalize(
59 				struct _prop_object_externalize_context *,
60 				void *);
61 static bool	_prop_array_equals(prop_object_t, prop_object_t,
62 				   void **, void **,
63 				   prop_object_t *, prop_object_t *);
64 static void	_prop_array_equals_finish(prop_object_t, prop_object_t);
65 static prop_object_iterator_t _prop_array_iterator_locked(prop_array_t);
66 static prop_object_t _prop_array_iterator_next_object_locked(void *);
67 static void _prop_array_iterator_reset_locked(void *);
68 
69 static const struct _prop_object_type _prop_object_type_array = {
70 	.pot_type		=	PROP_TYPE_ARRAY,
71 	.pot_free		=	_prop_array_free,
72 	.pot_emergency_free	=	_prop_array_emergency_free,
73 	.pot_extern		=	_prop_array_externalize,
74 	.pot_equals		=	_prop_array_equals,
75 	.pot_equals_finish	=	_prop_array_equals_finish,
76 };
77 
78 #define	prop_object_is_array(x) 	\
79 	((x) != NULL && (x)->pa_obj.po_type == &_prop_object_type_array)
80 
81 #define	prop_array_is_immutable(x) (((x)->pa_flags & PA_F_IMMUTABLE) != 0)
82 
83 struct _prop_array_iterator {
84 	struct _prop_object_iterator pai_base;
85 	unsigned int		pai_index;
86 };
87 
88 #define	EXPAND_STEP		16
89 
90 static int
91 _prop_array_free(prop_stack_t stack, prop_object_t *obj)
92 {
93 	prop_array_t pa = *obj;
94 	prop_object_t po;
95 
96 	_PROP_ASSERT(pa->pa_count <= pa->pa_capacity);
97 	_PROP_ASSERT((pa->pa_capacity == 0 && pa->pa_array == NULL) ||
98 		     (pa->pa_capacity != 0 && pa->pa_array != NULL));
99 
100 	/* The easy case is an empty array, just free and return. */
101 	if (pa->pa_count == 0) {
102 		if (pa->pa_array != NULL)
103 			_PROP_FREE(pa->pa_array, M_PROP_ARRAY);
104 
105 		_PROP_RWLOCK_DESTROY(pa->pa_rwlock);
106 
107 		_PROP_POOL_PUT(_prop_array_pool, pa);
108 
109 		return (_PROP_OBJECT_FREE_DONE);
110 	}
111 
112 	po = pa->pa_array[pa->pa_count - 1];
113 	_PROP_ASSERT(po != NULL);
114 
115 	if (stack == NULL) {
116 		/*
117 		 * If we are in emergency release mode,
118 		 * just let caller recurse down.
119 		 */
120 		*obj = po;
121 		return (_PROP_OBJECT_FREE_FAILED);
122 	}
123 
124 	/* Otherwise, try to push the current object on the stack. */
125 	if (!_prop_stack_push(stack, pa, NULL, NULL, NULL)) {
126 		/* Push failed, entering emergency release mode. */
127 		return (_PROP_OBJECT_FREE_FAILED);
128 	}
129 	/* Object pushed on stack, caller will release it. */
130 	--pa->pa_count;
131 	*obj = po;
132 	return (_PROP_OBJECT_FREE_RECURSE);
133 }
134 
135 static void
136 _prop_array_emergency_free(prop_object_t obj)
137 {
138 	prop_array_t pa = obj;
139 
140 	_PROP_ASSERT(pa->pa_count != 0);
141 	--pa->pa_count;
142 }
143 
144 static bool
145 _prop_array_externalize(struct _prop_object_externalize_context *ctx,
146 			void *v)
147 {
148 	prop_array_t pa = v;
149 	struct _prop_object *po;
150 	prop_object_iterator_t pi;
151 	unsigned int i;
152 	bool rv = false;
153 
154 	_PROP_RWLOCK_RDLOCK(pa->pa_rwlock);
155 
156 	if (pa->pa_count == 0) {
157 		_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
158 		return (_prop_object_externalize_empty_tag(ctx, "array"));
159 	}
160 
161 	/* XXXJRT Hint "count" for the internalize step? */
162 	if (_prop_object_externalize_start_tag(ctx, "array") == false ||
163 	    _prop_object_externalize_append_char(ctx, '\n') == false)
164 		goto out;
165 
166 	pi = _prop_array_iterator_locked(pa);
167 	if (pi == NULL)
168 		goto out;
169 
170 	ctx->poec_depth++;
171 	_PROP_ASSERT(ctx->poec_depth != 0);
172 
173 	while ((po = _prop_array_iterator_next_object_locked(pi)) != NULL) {
174 		if ((*po->po_type->pot_extern)(ctx, po) == false) {
175 			prop_object_iterator_release(pi);
176 			goto out;
177 		}
178 	}
179 
180 	prop_object_iterator_release(pi);
181 
182 	ctx->poec_depth--;
183 	for (i = 0; i < ctx->poec_depth; i++) {
184 		if (_prop_object_externalize_append_char(ctx, '\t') == false)
185 			goto out;
186 	}
187 	if (_prop_object_externalize_end_tag(ctx, "array") == false)
188 		goto out;
189 
190 	rv = true;
191 
192  out:
193  	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
194 	return (rv);
195 }
196 
197 /* ARGSUSED */
198 static bool
199 _prop_array_equals(prop_object_t v1, prop_object_t v2,
200     void **stored_pointer1, void **stored_pointer2,
201     prop_object_t *next_obj1, prop_object_t *next_obj2)
202 {
203 	prop_array_t array1 = v1;
204 	prop_array_t array2 = v2;
205 	uintptr_t idx;
206 	bool rv = _PROP_OBJECT_EQUALS_FALSE;
207 
208 	if (array1 == array2)
209 		return (_PROP_OBJECT_EQUALS_TRUE);
210 
211 	_PROP_ASSERT(*stored_pointer1 == *stored_pointer2);
212 	idx = (uintptr_t)*stored_pointer1;
213 
214 	/* For the first iteration, lock the objects. */
215 	if (idx == 0) {
216 		if ((uintptr_t)array1 < (uintptr_t)array2) {
217 			_PROP_RWLOCK_RDLOCK(array1->pa_rwlock);
218 			_PROP_RWLOCK_RDLOCK(array2->pa_rwlock);
219 		} else {
220 			_PROP_RWLOCK_RDLOCK(array2->pa_rwlock);
221 			_PROP_RWLOCK_RDLOCK(array1->pa_rwlock);
222 		}
223 	}
224 
225 	if (array1->pa_count != array2->pa_count)
226 		goto out;
227 	if (idx == array1->pa_count) {
228 		rv = true;
229 		goto out;
230 	}
231 	_PROP_ASSERT(idx < array1->pa_count);
232 
233 	*stored_pointer1 = (void *)(idx + 1);
234 	*stored_pointer2 = (void *)(idx + 1);
235 
236 	*next_obj1 = array1->pa_array[idx];
237 	*next_obj2 = array2->pa_array[idx];
238 
239 	return (_PROP_OBJECT_EQUALS_RECURSE);
240 
241  out:
242 	_PROP_RWLOCK_UNLOCK(array1->pa_rwlock);
243 	_PROP_RWLOCK_UNLOCK(array2->pa_rwlock);
244 	return (rv);
245 }
246 
247 static void
248 _prop_array_equals_finish(prop_object_t v1, prop_object_t v2)
249 {
250 	_PROP_RWLOCK_UNLOCK(((prop_array_t)v1)->pa_rwlock);
251 	_PROP_RWLOCK_UNLOCK(((prop_array_t)v2)->pa_rwlock);
252 }
253 
254 static prop_array_t
255 _prop_array_alloc(unsigned int capacity)
256 {
257 	prop_array_t pa;
258 	prop_object_t *array;
259 
260 	if (capacity != 0) {
261 		array = _PROP_CALLOC(capacity * sizeof(prop_object_t),
262 				     M_PROP_ARRAY);
263 		if (array == NULL)
264 			return (NULL);
265 	} else
266 		array = NULL;
267 
268 
269 	pa = _PROP_POOL_GET(_prop_array_pool);
270 	if (pa != NULL) {
271 		_prop_object_init(&pa->pa_obj, &_prop_object_type_array);
272 		pa->pa_obj.po_type = &_prop_object_type_array;
273 
274 		_PROP_RWLOCK_INIT(pa->pa_rwlock);
275 		pa->pa_array = array;
276 		pa->pa_capacity = capacity;
277 		pa->pa_count = 0;
278 		pa->pa_flags = 0;
279 
280 		pa->pa_version = 0;
281 	} else if (array != NULL)
282 		_PROP_FREE(array, M_PROP_ARRAY);
283 
284 	return (pa);
285 }
286 
287 static bool
288 _prop_array_expand(prop_array_t pa, unsigned int capacity)
289 {
290 	prop_object_t *array, *oarray;
291 
292 	/*
293 	 * Array must be WRITE-LOCKED.
294 	 */
295 
296 	oarray = pa->pa_array;
297 
298 	array = _PROP_CALLOC(capacity * sizeof(*array), M_PROP_ARRAY);
299 	if (array == NULL)
300 		return (false);
301 	if (oarray != NULL)
302 		memcpy(array, oarray, pa->pa_capacity * sizeof(*array));
303 	pa->pa_array = array;
304 	pa->pa_capacity = capacity;
305 
306 	if (oarray != NULL)
307 		_PROP_FREE(oarray, M_PROP_ARRAY);
308 
309 	return (true);
310 }
311 
312 static prop_object_t
313 _prop_array_iterator_next_object_locked(void *v)
314 {
315 	struct _prop_array_iterator *pai = v;
316 	prop_array_t pa = pai->pai_base.pi_obj;
317 	prop_object_t po = NULL;
318 
319 	_PROP_ASSERT(prop_object_is_array(pa));
320 
321 	if (pa->pa_version != pai->pai_base.pi_version)
322 		goto out;	/* array changed during iteration */
323 
324 	_PROP_ASSERT(pai->pai_index <= pa->pa_count);
325 
326 	if (pai->pai_index == pa->pa_count)
327 		goto out;	/* we've iterated all objects */
328 
329 	po = pa->pa_array[pai->pai_index];
330 	pai->pai_index++;
331 
332  out:
333 	return (po);
334 }
335 
336 static prop_object_t
337 _prop_array_iterator_next_object(void *v)
338 {
339 	struct _prop_array_iterator *pai = v;
340 	prop_array_t pa __unused = pai->pai_base.pi_obj;
341 	prop_object_t po;
342 
343 	_PROP_ASSERT(prop_object_is_array(pa));
344 
345 	_PROP_RWLOCK_RDLOCK(pa->pa_rwlock);
346 	po = _prop_array_iterator_next_object_locked(pai);
347 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
348 	return (po);
349 }
350 
351 static void
352 _prop_array_iterator_reset_locked(void *v)
353 {
354 	struct _prop_array_iterator *pai = v;
355 	prop_array_t pa = pai->pai_base.pi_obj;
356 
357 	_PROP_ASSERT(prop_object_is_array(pa));
358 
359 	pai->pai_index = 0;
360 	pai->pai_base.pi_version = pa->pa_version;
361 }
362 
363 static void
364 _prop_array_iterator_reset(void *v)
365 {
366 	struct _prop_array_iterator *pai = v;
367 	prop_array_t pa __unused = pai->pai_base.pi_obj;
368 
369 	_PROP_ASSERT(prop_object_is_array(pa));
370 
371 	_PROP_RWLOCK_RDLOCK(pa->pa_rwlock);
372 	_prop_array_iterator_reset_locked(pai);
373 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
374 }
375 
376 /*
377  * prop_array_create --
378  *	Create an empty array.
379  */
380 prop_array_t
381 prop_array_create(void)
382 {
383 
384 	return (_prop_array_alloc(0));
385 }
386 
387 /*
388  * prop_array_create_with_capacity --
389  *	Create an array with the capacity to store N objects.
390  */
391 prop_array_t
392 prop_array_create_with_capacity(unsigned int capacity)
393 {
394 
395 	return (_prop_array_alloc(capacity));
396 }
397 
398 /*
399  * prop_array_copy --
400  *	Copy an array.  The new array has an initial capacity equal to
401  *	the number of objects stored in the original array.  The new
402  *	array contains references to the original array's objects, not
403  *	copies of those objects (i.e. a shallow copy).
404  */
405 prop_array_t
406 prop_array_copy(prop_array_t opa)
407 {
408 	prop_array_t pa;
409 	prop_object_t po;
410 	unsigned int idx;
411 
412 	if (! prop_object_is_array(opa))
413 		return (NULL);
414 
415 	_PROP_RWLOCK_RDLOCK(opa->pa_rwlock);
416 
417 	pa = _prop_array_alloc(opa->pa_count);
418 	if (pa != NULL) {
419 		for (idx = 0; idx < opa->pa_count; idx++) {
420 			po = opa->pa_array[idx];
421 			prop_object_retain(po);
422 			pa->pa_array[idx] = po;
423 		}
424 		pa->pa_count = opa->pa_count;
425 		pa->pa_flags = opa->pa_flags;
426 	}
427 	_PROP_RWLOCK_UNLOCK(opa->pa_rwlock);
428 	return (pa);
429 }
430 
431 /*
432  * prop_array_copy_mutable --
433  *	Like prop_array_copy(), but the resulting array is mutable.
434  */
435 prop_array_t
436 prop_array_copy_mutable(prop_array_t opa)
437 {
438 	prop_array_t pa;
439 
440 	pa = prop_array_copy(opa);
441 	if (pa != NULL)
442 		pa->pa_flags &= ~PA_F_IMMUTABLE;
443 
444 	return (pa);
445 }
446 
447 /*
448  * prop_array_capacity --
449  *	Return the capacity of the array.
450  */
451 unsigned int
452 prop_array_capacity(prop_array_t pa)
453 {
454 	unsigned int rv;
455 
456 	if (! prop_object_is_array(pa))
457 		return (0);
458 
459 	_PROP_RWLOCK_RDLOCK(pa->pa_rwlock);
460 	rv = pa->pa_capacity;
461 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
462 
463 	return (rv);
464 }
465 
466 /*
467  * prop_array_count --
468  *	Return the number of objects stored in the array.
469  */
470 unsigned int
471 prop_array_count(prop_array_t pa)
472 {
473 	unsigned int rv;
474 
475 	if (! prop_object_is_array(pa))
476 		return (0);
477 
478 	_PROP_RWLOCK_RDLOCK(pa->pa_rwlock);
479 	rv = pa->pa_count;
480 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
481 
482 	return (rv);
483 }
484 
485 /*
486  * prop_array_ensure_capacity --
487  *	Ensure that the array has the capacity to store the specified
488  *	total number of objects (inluding the objects already stored
489  *	in the array).
490  */
491 bool
492 prop_array_ensure_capacity(prop_array_t pa, unsigned int capacity)
493 {
494 	bool rv;
495 
496 	if (! prop_object_is_array(pa))
497 		return (false);
498 
499 	_PROP_RWLOCK_WRLOCK(pa->pa_rwlock);
500 	if (capacity > pa->pa_capacity)
501 		rv = _prop_array_expand(pa, capacity);
502 	else
503 		rv = true;
504 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
505 
506 	return (rv);
507 }
508 
509 static prop_object_iterator_t
510 _prop_array_iterator_locked(prop_array_t pa)
511 {
512 	struct _prop_array_iterator *pai;
513 
514 	if (! prop_object_is_array(pa))
515 		return (NULL);
516 
517 	pai = _PROP_CALLOC(sizeof(*pai), M_TEMP);
518 	if (pai == NULL)
519 		return (NULL);
520 	pai->pai_base.pi_next_object = _prop_array_iterator_next_object;
521 	pai->pai_base.pi_reset = _prop_array_iterator_reset;
522 	prop_object_retain(pa);
523 	pai->pai_base.pi_obj = pa;
524 	_prop_array_iterator_reset_locked(pai);
525 
526 	return (&pai->pai_base);
527 }
528 
529 /*
530  * prop_array_iterator --
531  *	Return an iterator for the array.  The array is retained by
532  *	the iterator.
533  */
534 prop_object_iterator_t
535 prop_array_iterator(prop_array_t pa)
536 {
537 	prop_object_iterator_t pi;
538 
539 	_PROP_RWLOCK_RDLOCK(pa->pa_rwlock);
540 	pi = _prop_array_iterator_locked(pa);
541 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
542 	return (pi);
543 }
544 
545 /*
546  * prop_array_make_immutable --
547  *	Make the array immutable.
548  */
549 void
550 prop_array_make_immutable(prop_array_t pa)
551 {
552 
553 	_PROP_RWLOCK_WRLOCK(pa->pa_rwlock);
554 	if (prop_array_is_immutable(pa) == false)
555 		pa->pa_flags |= PA_F_IMMUTABLE;
556 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
557 }
558 
559 /*
560  * prop_array_mutable --
561  *	Returns true if the array is mutable.
562  */
563 bool
564 prop_array_mutable(prop_array_t pa)
565 {
566 	bool rv;
567 
568 	_PROP_RWLOCK_RDLOCK(pa->pa_rwlock);
569 	rv = prop_array_is_immutable(pa) == false;
570 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
571 
572 	return (rv);
573 }
574 
575 /*
576  * prop_array_get --
577  *	Return the object stored at the specified array index.
578  */
579 prop_object_t
580 prop_array_get(prop_array_t pa, unsigned int idx)
581 {
582 	prop_object_t po = NULL;
583 
584 	if (! prop_object_is_array(pa))
585 		return (NULL);
586 
587 	_PROP_RWLOCK_RDLOCK(pa->pa_rwlock);
588 	if (idx >= pa->pa_count)
589 		goto out;
590 	po = pa->pa_array[idx];
591 	_PROP_ASSERT(po != NULL);
592  out:
593 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
594 	return (po);
595 }
596 
597 static bool
598 _prop_array_add(prop_array_t pa, prop_object_t po)
599 {
600 
601 	/*
602 	 * Array must be WRITE-LOCKED.
603 	 */
604 
605 	_PROP_ASSERT(pa->pa_count <= pa->pa_capacity);
606 
607 	if (prop_array_is_immutable(pa) ||
608 	    (pa->pa_count == pa->pa_capacity &&
609 	    _prop_array_expand(pa, pa->pa_capacity + EXPAND_STEP) == false))
610 		return (false);
611 
612 	prop_object_retain(po);
613 	pa->pa_array[pa->pa_count++] = po;
614 	pa->pa_version++;
615 
616 	return (true);
617 }
618 
619 /*
620  * prop_array_set --
621  *	Store a reference to an object at the specified array index.
622  *	This method is not allowed to create holes in the array; the
623  *	caller must either be setting the object just beyond the existing
624  *	count or replacing an already existing object reference.
625  */
626 bool
627 prop_array_set(prop_array_t pa, unsigned int idx, prop_object_t po)
628 {
629 	prop_object_t opo;
630 	bool rv = false;
631 
632 	if (! prop_object_is_array(pa))
633 		return (false);
634 
635 	_PROP_RWLOCK_WRLOCK(pa->pa_rwlock);
636 
637 	if (prop_array_is_immutable(pa))
638 		goto out;
639 
640 	if (idx == pa->pa_count) {
641 		rv = _prop_array_add(pa, po);
642 		goto out;
643 	}
644 
645 	_PROP_ASSERT(idx < pa->pa_count);
646 
647 	opo = pa->pa_array[idx];
648 	_PROP_ASSERT(opo != NULL);
649 
650 	prop_object_retain(po);
651 	pa->pa_array[idx] = po;
652 	pa->pa_version++;
653 
654 	prop_object_release(opo);
655 
656 	rv = true;
657 
658  out:
659 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
660 	return (rv);
661 }
662 
663 /*
664  * prop_array_add --
665  *	Add a refrerence to an object to the specified array, appending
666  *	to the end and growing the array's capacity, if necessary.
667  */
668 bool
669 prop_array_add(prop_array_t pa, prop_object_t po)
670 {
671 	bool rv;
672 
673 	if (! prop_object_is_array(pa))
674 		return (false);
675 
676 	_PROP_RWLOCK_WRLOCK(pa->pa_rwlock);
677 	rv = _prop_array_add(pa, po);
678 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
679 
680 	return (rv);
681 }
682 
683 /*
684  * prop_array_remove --
685  *	Remove the reference to an object from an array at the specified
686  *	index.  The array will be compacted following the removal.
687  */
688 void
689 prop_array_remove(prop_array_t pa, unsigned int idx)
690 {
691 	prop_object_t po;
692 
693 	if (! prop_object_is_array(pa))
694 		return;
695 
696 	_PROP_RWLOCK_WRLOCK(pa->pa_rwlock);
697 
698 	_PROP_ASSERT(idx < pa->pa_count);
699 
700 	/* XXX Should this be a _PROP_ASSERT()? */
701 	if (prop_array_is_immutable(pa)) {
702 		_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
703 		return;
704 	}
705 
706 	po = pa->pa_array[idx];
707 	_PROP_ASSERT(po != NULL);
708 
709 	for (++idx; idx < pa->pa_count; idx++)
710 		pa->pa_array[idx - 1] = pa->pa_array[idx];
711 	pa->pa_count--;
712 	pa->pa_version++;
713 
714 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
715 
716 	prop_object_release(po);
717 }
718 
719 /*
720  * prop_array_equals --
721  *	Return true if the two arrays are equivalent.  Note we do a
722  *	by-value comparison of the objects in the array.
723  */
724 bool
725 prop_array_equals(prop_array_t array1, prop_array_t array2)
726 {
727 	if (!prop_object_is_array(array1) || !prop_object_is_array(array2))
728 		return (false);
729 
730 	return (prop_object_equals(array1, array2));
731 }
732 
733 /*
734  * prop_array_externalize --
735  *	Externalize an array, return a NUL-terminated buffer
736  *	containing the XML-style representation.  The buffer is allocated
737  * 	with the M_TEMP memory type.
738  */
739 char *
740 prop_array_externalize(prop_array_t pa)
741 {
742 	struct _prop_object_externalize_context *ctx;
743 	char *cp;
744 
745 	ctx = _prop_object_externalize_context_alloc();
746 	if (ctx == NULL)
747 		return (NULL);
748 
749 	if (_prop_object_externalize_header(ctx) == false ||
750 	    (*pa->pa_obj.po_type->pot_extern)(ctx, pa) == false ||
751 	    _prop_object_externalize_footer(ctx) == false) {
752 		/* We are responsible for releasing the buffer. */
753 		_PROP_FREE(ctx->poec_buf, M_TEMP);
754 		_prop_object_externalize_context_free(ctx);
755 		return (NULL);
756 	}
757 
758 	cp = ctx->poec_buf;
759 	_prop_object_externalize_context_free(ctx);
760 
761 	return (cp);
762 }
763 
764 /*
765  * _prop_array_internalize --
766  *	Parse an <array>...</array> and return the object created from the
767  *	external representation.
768  */
769 static bool _prop_array_internalize_body(prop_stack_t, prop_object_t *,
770     struct _prop_object_internalize_context *);
771 
772 bool
773 _prop_array_internalize(prop_stack_t stack, prop_object_t *obj,
774     struct _prop_object_internalize_context *ctx)
775 {
776 	/* We don't currently understand any attributes. */
777 	if (ctx->poic_tagattr != NULL)
778 		return (true);
779 
780 	*obj = prop_array_create();
781 	/*
782 	 * We are done if the create failed or no child elements exist.
783 	 */
784 	if (*obj == NULL || ctx->poic_is_empty_element)
785 		return (true);
786 
787 	/*
788 	 * Opening tag is found, now continue to the first element.
789 	 */
790 	return (_prop_array_internalize_body(stack, obj, ctx));
791 }
792 
793 static bool
794 _prop_array_internalize_continue(prop_stack_t stack,
795     prop_object_t *obj,
796     struct _prop_object_internalize_context *ctx,
797     void *data, prop_object_t child)
798 {
799 	prop_array_t array;
800 
801 	_PROP_ASSERT(data == NULL);
802 
803 	if (child == NULL)
804 		goto bad; /* Element could not be parsed. */
805 
806 	array = *obj;
807 
808 	if (prop_array_add(array, child) == false) {
809 		prop_object_release(child);
810 		goto bad;
811 	}
812 	prop_object_release(child);
813 
814 	/*
815 	 * Current element is processed and added, look for next.
816 	 */
817 	return (_prop_array_internalize_body(stack, obj, ctx));
818 
819  bad:
820 	prop_object_release(*obj);
821 	*obj = NULL;
822 	return (true);
823 }
824 
825 static bool
826 _prop_array_internalize_body(prop_stack_t stack, prop_object_t *obj,
827     struct _prop_object_internalize_context *ctx)
828 {
829 	prop_array_t array = *obj;
830 
831 	_PROP_ASSERT(array != NULL);
832 
833 	/* Fetch the next tag. */
834 	if (_prop_object_internalize_find_tag(ctx, NULL,
835 				_PROP_TAG_TYPE_EITHER) == false)
836 		goto bad;
837 
838 	/* Check to see if this is the end of the array. */
839 	if (_PROP_TAG_MATCH(ctx, "array") &&
840 	    ctx->poic_tag_type == _PROP_TAG_TYPE_END) {
841 		/* It is, so don't iterate any further. */
842 		return (true);
843 	}
844 
845 	if (_prop_stack_push(stack, array,
846 			     _prop_array_internalize_continue, NULL, NULL))
847 		return (false);
848 
849  bad:
850 	prop_object_release(array);
851 	*obj = NULL;
852 	return (true);
853 }
854 
855 /*
856  * prop_array_internalize --
857  *	Create an array by parsing the XML-style representation.
858  */
859 prop_array_t
860 prop_array_internalize(const char *xml)
861 {
862 	return _prop_generic_internalize(xml, "array");
863 }
864 
865 #if !defined(_KERNEL) && !defined(_STANDALONE)
866 /*
867  * prop_array_externalize_to_file --
868  *	Externalize an array to the specified file.
869  */
870 bool
871 prop_array_externalize_to_file(prop_array_t array, const char *fname)
872 {
873 	char *xml;
874 	bool rv;
875 	int save_errno = 0;	/* XXXGCC -Wuninitialized [mips, ...] */
876 
877 	xml = prop_array_externalize(array);
878 	if (xml == NULL)
879 		return (false);
880 	rv = _prop_object_externalize_write_file(fname, xml, strlen(xml));
881 	if (rv == false)
882 		save_errno = errno;
883 	_PROP_FREE(xml, M_TEMP);
884 	if (rv == false)
885 		errno = save_errno;
886 
887 	return (rv);
888 }
889 
890 /*
891  * prop_array_internalize_from_file --
892  *	Internalize an array from a file.
893  */
894 prop_array_t
895 prop_array_internalize_from_file(const char *fname)
896 {
897 	struct _prop_object_internalize_mapped_file *mf;
898 	prop_array_t array;
899 
900 	mf = _prop_object_internalize_map_file(fname);
901 	if (mf == NULL)
902 		return (NULL);
903 	array = prop_array_internalize(mf->poimf_xml);
904 	_prop_object_internalize_unmap_file(mf);
905 
906 	return (array);
907 }
908 #endif /* _KERNEL && !_STANDALONE */
909