[btr] Add more documentation.
[paraslash.git] / buffer_tree.c
1 #include <regex.h>
2 #include <stdbool.h>
3
4 #include "para.h"
5 #include "list.h"
6 #include "string.h"
7 #include "buffer_tree.h"
8 #include "error.h"
9 #include "sched.h"
10
11 struct btr_pool {
12 char *name;
13 char *area_start;
14 char *area_end;
15 char *rhead;
16 char *whead;
17 };
18
19 enum btr_buffer_flags {
20 /* changes the way the buffer is deallocated */
21 BTR_BF_BTR_POOL = 1,
22 };
23
24 struct btr_buffer {
25 char *buf;
26 size_t size;
27 /** The number of references to this buffer. */
28 int refcount;
29 struct btr_pool *pool;
30 };
31
32 struct btr_buffer_reference {
33 struct btr_buffer *btrb;
34 size_t consumed;
35 /* Each buffer reference belongs to the buffer queue list of some buffer tree node. */
36 struct list_head node;
37 size_t wrap_count;
38 };
39
40 struct btr_node {
41 char *name;
42 struct btr_node *parent;
43 /* The position of this btr node in the buffer tree. */
44 struct list_head node;
45 /* The children nodes of this btr node are linked together in a list. */
46 struct list_head children;
47 /* Time of first data transfer. */
48 struct timeval start;
49 /**
50 * The input queue is a list of references to btr buffers. Each item on
51 * the list represents an input buffer which has not been completely
52 * used by this btr node.
53 */
54 struct list_head input_queue;
55 btr_command_handler execute;
56 void *context;
57 };
58
59 struct btr_pool *btr_pool_new(const char *name, size_t area_size)
60 {
61 struct btr_pool *btrp;
62
63 PARA_INFO_LOG("%s, %zu bytes\n", name, area_size);
64 btrp = para_malloc(sizeof(*btrp));
65 btrp->area_start = para_malloc(area_size);
66 btrp->area_end = btrp->area_start + area_size;
67 btrp->rhead = btrp->area_start;
68 btrp->whead = btrp->area_start;
69 btrp->name = para_strdup(name);
70 return btrp;
71 }
72
73 /* whead = NULL means area full */
74
75 void btr_pool_free(struct btr_pool *btrp)
76 {
77 if (!btrp)
78 return;
79 free(btrp->area_start);
80 free(btrp->name);
81 free(btrp);
82 }
83
84 size_t btr_pool_size(struct btr_pool *btrp)
85 {
86 return btrp->area_end - btrp->area_start;
87 }
88
89 size_t btr_pool_filled(struct btr_pool *btrp)
90 {
91 if (!btrp->whead)
92 return btr_pool_size(btrp);
93 if (btrp->rhead <= btrp->whead)
94 return btrp->whead - btrp->rhead;
95 return btr_pool_size(btrp) - (btrp->rhead - btrp->whead);
96 }
97
98 size_t btr_pool_unused(struct btr_pool *btrp)
99 {
100 return btr_pool_size(btrp) - btr_pool_filled(btrp);
101 }
102
103 /*
104 * Return maximal size available for one read. This is
105 * smaller than the value returned by btr_pool_unused().
106 */
107 size_t btr_pool_available(struct btr_pool *btrp)
108 {
109 if (!btrp->whead)
110 return 0;
111 if (btrp->rhead <= btrp->whead)
112 return btrp->area_end - btrp->whead;
113 return btrp->rhead - btrp->whead;
114 }
115
116 size_t btr_pool_get_buffer(struct btr_pool *btrp, char **result)
117 {
118 if (result)
119 *result = btrp->whead;
120 return btr_pool_available(btrp);
121 }
122
123 void btr_pool_allocate(struct btr_pool *btrp, size_t size)
124 {
125 char *end;
126
127 if (size == 0)
128 return;
129 assert(size <= btr_pool_available(btrp));
130 end = btrp->whead + size;
131 assert(end <= btrp->area_end);
132
133 if (end == btrp->area_end) {
134 PARA_DEBUG_LOG("%s: end of pool area reached\n", btrp->name);
135 end = btrp->area_start;
136 }
137 if (end == btrp->rhead) {
138 PARA_DEBUG_LOG("%s btrp buffer full\n", btrp->name);
139 end = NULL; /* buffer full */
140 }
141 btrp->whead = end;
142 }
143
144 static void btr_pool_deallocate(struct btr_pool *btrp, size_t size)
145 {
146 char *end = btrp->rhead + size;
147
148 if (size == 0)
149 return;
150 assert(end <= btrp->area_end);
151 assert(size <= btr_pool_filled(btrp));
152 if (end == btrp->area_end)
153 end = btrp->area_start;
154 if (!btrp->whead)
155 btrp->whead = btrp->rhead;
156 btrp->rhead = end;
157 if (btrp->rhead == btrp->whead)
158 btrp->rhead = btrp->whead = btrp->area_start;
159 }
160
161 #define FOR_EACH_CHILD(_tn, _btrn) list_for_each_entry((_tn), \
162 &((_btrn)->children), node)
163 #define FOR_EACH_CHILD_SAFE(_tn, _tmp, _btrn) \
164 list_for_each_entry_safe((_tn), (_tmp), &((_btrn)->children), node)
165
166 #define FOR_EACH_BUFFER_REF(_br, _btrn) \
167 list_for_each_entry((_br), &(_btrn)->input_queue, node)
168 #define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
169 list_for_each_entry_safe((_br), (_tmp), &(_btrn)->input_queue, node)
170
171 struct btr_node *btr_new_node(struct btr_node_description *bnd)
172 {
173 struct btr_node *btrn = para_malloc(sizeof(*btrn));
174
175 btrn->name = para_strdup(bnd->name);
176 btrn->parent = bnd->parent;
177 btrn->execute = bnd->handler;
178 btrn->context = bnd->context;
179 btrn->start.tv_sec = 0;
180 btrn->start.tv_usec = 0;
181 INIT_LIST_HEAD(&btrn->children);
182 INIT_LIST_HEAD(&btrn->input_queue);
183 if (!bnd->child) {
184 if (bnd->parent) {
185 list_add_tail(&btrn->node, &bnd->parent->children);
186 PARA_INFO_LOG("new leaf node: %s (child of %s)\n",
187 bnd->name, bnd->parent->name);
188 } else
189 PARA_INFO_LOG("added %s as btr root\n", bnd->name);
190 goto out;
191 }
192 if (!bnd->parent) {
193 assert(!bnd->child->parent);
194 PARA_INFO_LOG("new root: %s (was %s)\n",
195 bnd->name, bnd->child->name);
196 btrn->parent = NULL;
197 list_add_tail(&bnd->child->node, &btrn->children);
198 /* link it in */
199 bnd->child->parent = btrn;
200 goto out;
201 }
202 PARA_EMERG_LOG("inserting internal nodes not yet supported.\n");
203 exit(EXIT_FAILURE);
204 assert(bnd->child->parent == bnd->parent);
205 out:
206 return btrn;
207 }
208
209 /*
210 * Allocate a new btr buffer.
211 *
212 * The freshly allocated buffer will have a zero refcount and will
213 * not be associated with a btr pool.
214 */
215 static struct btr_buffer *new_btrb(char *buf, size_t size)
216 {
217 struct btr_buffer *btrb = para_calloc(sizeof(*btrb));
218
219 btrb->buf = buf;
220 btrb->size = size;
221 return btrb;
222 }
223
224 static void dealloc_buffer(struct btr_buffer *btrb)
225 {
226 if (btrb->pool)
227 btr_pool_deallocate(btrb->pool, btrb->size);
228 else
229 free(btrb->buf);
230 }
231
232 static struct btr_buffer_reference *get_first_input_br(struct btr_node *btrn)
233 {
234 if (list_empty(&btrn->input_queue))
235 return NULL;
236 return list_first_entry(&btrn->input_queue,
237 struct btr_buffer_reference, node);
238 }
239
240 /*
241 * Deallocate the reference, release the resources if refcount drops to zero.
242 */
243 static void btr_drop_buffer_reference(struct btr_buffer_reference *br)
244 {
245 struct btr_buffer *btrb = br->btrb;
246
247 list_del(&br->node);
248 free(br);
249 btrb->refcount--;
250 if (btrb->refcount == 0) {
251 dealloc_buffer(btrb);
252 free(btrb);
253 }
254 }
255
256 static void add_btrb_to_children(struct btr_buffer *btrb,
257 struct btr_node *btrn, size_t consumed)
258 {
259 struct btr_node *ch;
260
261 if (btrn->start.tv_sec == 0)
262 btrn->start = *now;
263 FOR_EACH_CHILD(ch, btrn) {
264 struct btr_buffer_reference *br = para_calloc(sizeof(*br));
265 br->btrb = btrb;
266 br->consumed = consumed;
267 list_add_tail(&br->node, &ch->input_queue);
268 btrb->refcount++;
269 if (ch->start.tv_sec == 0)
270 ch->start = *now;
271 }
272 }
273
274 void btr_add_output(char *buf, size_t size, struct btr_node *btrn)
275 {
276 struct btr_buffer *btrb;
277
278 assert(size != 0);
279 if (list_empty(&btrn->children)) {
280 free(buf);
281 return;
282 }
283 btrb = new_btrb(buf, size);
284 add_btrb_to_children(btrb, btrn, 0);
285 }
286
287 void btr_add_output_pool(struct btr_pool *btrp, size_t size,
288 struct btr_node *btrn)
289 {
290 struct btr_buffer *btrb;
291 char *buf;
292 size_t avail;
293
294 assert(size != 0);
295 if (list_empty(&btrn->children))
296 return;
297 avail = btr_pool_get_buffer(btrp, &buf);
298 assert(avail >= size);
299 btr_pool_allocate(btrp, size);
300 btrb = new_btrb(buf, size);
301 btrb->pool = btrp;
302 add_btrb_to_children(btrb, btrn, 0);
303 }
304
305 void btr_copy(const void *src, size_t n, struct btr_pool *btrp,
306 struct btr_node *btrn)
307 {
308 char *buf;
309 size_t sz, copy;
310
311 if (n == 0)
312 return;
313 assert(n <= btr_pool_unused(btrp));
314 sz = btr_pool_get_buffer(btrp, &buf);
315 copy = PARA_MIN(sz, n);
316 memcpy(buf, src, copy);
317 btr_add_output_pool(btrp, copy, btrn);
318 if (copy == n)
319 return;
320 sz = btr_pool_get_buffer(btrp, &buf);
321 assert(sz >= n - copy);
322 memcpy(buf, src + copy, n - copy);
323 btr_add_output_pool(btrp, n - copy, btrn);
324 }
325
326 static void btr_pushdown_br(struct btr_buffer_reference *br, struct btr_node *btrn)
327 {
328 add_btrb_to_children(br->btrb, btrn, br->consumed);
329 btr_drop_buffer_reference(br);
330 }
331
332 void btr_pushdown(struct btr_node *btrn)
333 {
334 struct btr_buffer_reference *br, *tmp;
335
336 FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn)
337 btr_pushdown_br(br, btrn);
338 }
339
340 int btr_pushdown_one(struct btr_node *btrn)
341 {
342 struct btr_buffer_reference *br;
343
344 if (list_empty(&btrn->input_queue))
345 return 0;
346 br = list_first_entry(&btrn->input_queue, struct btr_buffer_reference, node);
347 btr_pushdown_br(br, btrn);
348 return 1;
349 }
350
351 /* Return true if this node has no children. */
352 bool btr_no_children(struct btr_node *btrn)
353 {
354 return list_empty(&btrn->children);
355 }
356
357 bool btr_no_parent(struct btr_node *btrn)
358 {
359 return !btrn->parent;
360 }
361
362 bool btr_inplace_ok(struct btr_node *btrn)
363 {
364 if (!btrn->parent)
365 return true;
366 return list_is_singular(&btrn->parent->children);
367 }
368
369 static inline size_t br_available_bytes(struct btr_buffer_reference *br)
370 {
371 return br->btrb->size - br->consumed;
372 }
373
374 size_t btr_get_buffer_by_reference(struct btr_buffer_reference *br, char **buf)
375 {
376 if (buf)
377 *buf = br->btrb->buf + br->consumed;
378 return br_available_bytes(br);
379 }
380
381 /**
382 * \return zero if the input buffer queue is empty.
383 */
384 size_t btr_next_buffer(struct btr_node *btrn, char **bufp)
385 {
386 struct btr_buffer_reference *br;
387 char *buf, *result = NULL;
388 size_t sz, rv = 0;
389
390 FOR_EACH_BUFFER_REF(br, btrn) {
391 sz = btr_get_buffer_by_reference(br, &buf);
392 if (!result) {
393 result = buf;
394 rv = sz;
395 if (!br->btrb->pool)
396 break;
397 continue;
398 }
399 if (!br->btrb->pool)
400 break;
401 if (result + rv != buf)
402 break;
403 rv += sz;
404 }
405 if (bufp)
406 *bufp = result;
407 return rv;
408 }
409
410 void btr_consume(struct btr_node *btrn, size_t numbytes)
411 {
412 struct btr_buffer_reference *br, *tmp;
413 size_t sz;
414
415 if (numbytes == 0)
416 return;
417 br = get_first_input_br(btrn);
418 assert(br);
419
420 if (br->wrap_count == 0) {
421 /*
422 * No wrap buffer. Drop buffer references whose buffer
423 * has been fully used. */
424 FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn) {
425 if (br->consumed + numbytes <= br->btrb->size) {
426 br->consumed += numbytes;
427 if (br->consumed == br->btrb->size)
428 btr_drop_buffer_reference(br);
429 return;
430 }
431 numbytes -= br->btrb->size - br->consumed;
432 btr_drop_buffer_reference(br);
433 }
434 assert(true);
435 }
436 /*
437
438 We have a wrap buffer, consume from it. If in total,
439 i.e. including previous calls to brt_consume(), less than
440 wrap_count has been consumed, there's nothing more we can do.
441
442 Otherwise we drop the wrap buffer and consume from subsequent
443 buffers of the input queue the correct amount of bytes. This
444 is the total number of bytes that have been consumed from the
445 wrap buffer.
446 */
447 PARA_DEBUG_LOG("consuming %zu/%zu bytes from wrap buffer\n", numbytes,
448 br_available_bytes(br));
449
450 assert(numbytes <= br_available_bytes(br));
451 if (br->consumed + numbytes < br->wrap_count) {
452 br->consumed += numbytes;
453 return;
454 }
455 PARA_DEBUG_LOG("dropping wrap buffer (%zu bytes)\n", br->btrb->size);
456 /* get rid of the wrap buffer */
457 sz = br->consumed + numbytes;
458 btr_drop_buffer_reference(br);
459 return btr_consume(btrn, sz);
460 }
461
462 static void flush_input_queue(struct btr_node *btrn)
463 {
464 struct btr_buffer_reference *br, *tmp;
465 FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn)
466 btr_drop_buffer_reference(br);
467 }
468
469 void btr_free_node(struct btr_node *btrn)
470 {
471 if (!btrn)
472 return;
473 free(btrn->name);
474 free(btrn);
475 }
476
477 void btr_remove_node(struct btr_node *btrn)
478 {
479 struct btr_node *ch;
480
481 if (!btrn)
482 return;
483 PARA_NOTICE_LOG("removing btr node %s from buffer tree\n", btrn->name);
484 FOR_EACH_CHILD(ch, btrn)
485 ch->parent = NULL;
486 flush_input_queue(btrn);
487 if (btrn->parent)
488 list_del(&btrn->node);
489 }
490
491 size_t btr_get_input_queue_size(struct btr_node *btrn)
492 {
493 struct btr_buffer_reference *br;
494 size_t size = 0, wrap_consumed = 0;
495
496 FOR_EACH_BUFFER_REF(br, btrn) {
497 if (br->wrap_count != 0) {
498 wrap_consumed = br->consumed;
499 continue;
500 }
501 size += br_available_bytes(br);
502 }
503 assert(wrap_consumed <= size);
504 size -= wrap_consumed;
505 return size;
506 }
507
508 void btr_splice_out_node(struct btr_node *btrn)
509 {
510 struct btr_node *ch, *tmp;
511
512 assert(btrn);
513 PARA_NOTICE_LOG("splicing out %s\n", btrn->name);
514 btr_pushdown(btrn);
515 if (btrn->parent)
516 list_del(&btrn->node);
517 FOR_EACH_CHILD_SAFE(ch, tmp, btrn) {
518 PARA_INFO_LOG("parent(%s): %s\n", ch->name,
519 btrn->parent? btrn->parent->name : "NULL");
520 ch->parent = btrn->parent;
521 if (btrn->parent)
522 list_move(&ch->node, &btrn->parent->children);
523 }
524 assert(list_empty(&btrn->children));
525 }
526
527 /**
528 * Return the size of the largest input queue.
529 *
530 * Iterates over all children of the given node.
531 */
532 size_t btr_bytes_pending(struct btr_node *btrn)
533 {
534 size_t max_size = 0;
535 struct btr_node *ch;
536
537 FOR_EACH_CHILD(ch, btrn) {
538 size_t size = btr_get_input_queue_size(ch);
539 max_size = PARA_MAX(max_size, size);
540 }
541 return max_size;
542 }
543
544 int btr_exec(struct btr_node *btrn, const char *command, char **value_result)
545 {
546 if (!btrn)
547 return -ERRNO_TO_PARA_ERROR(EINVAL);
548 if (!btrn->execute)
549 return -ERRNO_TO_PARA_ERROR(ENOTSUP);
550 return btrn->execute(btrn, command, value_result);
551 }
552
553 int btr_exec_up(struct btr_node *btrn, const char *command, char **value_result)
554 {
555 int ret;
556
557 for (; btrn; btrn = btrn->parent) {
558 struct btr_node *parent = btrn->parent;
559 if (!parent)
560 return -ERRNO_TO_PARA_ERROR(ENOTSUP);
561 if (!parent->execute)
562 continue;
563 PARA_INFO_LOG("parent: %s, cmd: %s\n", parent->name, command);
564 ret = parent->execute(parent, command, value_result);
565 if (ret == -ERRNO_TO_PARA_ERROR(ENOTSUP))
566 continue;
567 if (ret < 0)
568 return ret;
569 if (value_result && *value_result)
570 PARA_NOTICE_LOG("%s(%s): %s\n", command, parent->name,
571 *value_result);
572 return 1;
573 }
574 return -ERRNO_TO_PARA_ERROR(ENOTSUP);
575 }
576
577 void *btr_context(struct btr_node *btrn)
578 {
579 return btrn->context;
580 }
581
582 static bool need_buffer_pool_merge(struct btr_node *btrn)
583 {
584 struct btr_buffer_reference *br = get_first_input_br(btrn);
585
586 if (!br)
587 return false;
588 if (br->wrap_count != 0)
589 return true;
590 if (br->btrb->pool)
591 return true;
592 return false;
593 }
594
595 static void merge_input_pool(struct btr_node *btrn, size_t dest_size)
596 {
597 struct btr_buffer_reference *br, *wbr = NULL;
598 int num_refs; /* including wrap buffer */
599 char *buf, *buf1 = NULL, *buf2 = NULL;
600 size_t sz, sz1 = 0, sz2 = 0, wsz;
601
602 br = get_first_input_br(btrn);
603 if (!br || br_available_bytes(br) >= dest_size)
604 return;
605 num_refs = 0;
606 FOR_EACH_BUFFER_REF(br, btrn) {
607 num_refs++;
608 sz = btr_get_buffer_by_reference(br, &buf);
609 if (sz == 0)
610 break;
611 if (br->wrap_count != 0) {
612 assert(!wbr);
613 assert(num_refs == 1);
614 wbr = br;
615 if (sz >= dest_size)
616 return;
617 continue;
618 }
619 if (!buf1) {
620 buf1 = buf;
621 sz1 = sz;
622 goto next;
623 }
624 if (buf1 + sz1 == buf) {
625 sz1 += sz;
626 goto next;
627 }
628 if (!buf2) {
629 buf2 = buf;
630 sz2 = sz;
631 goto next;
632 }
633 assert(buf2 + sz2 == buf);
634 sz2 += sz;
635 next:
636 if (sz1 + sz2 >= dest_size)
637 break;
638 }
639 if (!buf2) /* nothing to do */
640 return;
641 assert(buf1 && sz2 > 0);
642 /*
643 * If the second buffer is large, we only take the first part of it to
644 * avoid having to memcpy() huge buffers.
645 */
646 sz2 = PARA_MIN(sz2, (size_t)(64 * 1024));
647 if (!wbr) {
648 /* Make a new wrap buffer combining buf1 and buf2. */
649 sz = sz1 + sz2;
650 buf = para_malloc(sz);
651 PARA_DEBUG_LOG("merging input buffers: (%p:%zu, %p:%zu) -> %p:%zu\n",
652 buf1, sz1, buf2, sz2, buf, sz);
653 memcpy(buf, buf1, sz1);
654 memcpy(buf + sz1, buf2, sz2);
655 br = para_calloc(sizeof(*br));
656 br->btrb = new_btrb(buf, sz);
657 br->btrb->refcount = 1;
658 br->consumed = 0;
659 /* This is a wrap buffer */
660 br->wrap_count = sz1;
661 para_list_add(&br->node, &btrn->input_queue);
662 return;
663 }
664 PARA_DEBUG_LOG("increasing wrap buffer, sz1: %zu, sz2: %zu\n", sz1, sz2);
665 /*
666 * We already have a wrap buffer, but it is too small. It might be
667 * partially used.
668 */
669 wsz = br_available_bytes(wbr);
670 if (wbr->wrap_count == sz1 && wbr->btrb->size >= sz1 + sz2) /* nothing we can do about it */
671 return;
672 sz = sz1 + sz2 - wbr->btrb->size; /* amount of new data */
673 wbr->btrb->size += sz;
674 wbr->btrb->buf = para_realloc(wbr->btrb->buf, wbr->btrb->size);
675 /* copy the new data to the end of the reallocated buffer */
676 assert(sz2 >= sz);
677 memcpy(wbr->btrb->buf + wbr->btrb->size - sz, buf2 + sz2 - sz, sz);
678 }
679
680 /**
681 * Merge the first two input buffers into one.
682 *
683 * This is a quite expensive operation.
684 *
685 * \return The number of buffers that have been available (zero, one or two).
686 */
687 static int merge_input(struct btr_node *btrn)
688 {
689 struct btr_buffer_reference *brs[2], *br;
690 char *bufs[2], *buf;
691 size_t szs[2], sz;
692 int i;
693
694 if (list_empty(&btrn->input_queue))
695 return 0;
696 if (list_is_singular(&btrn->input_queue))
697 return 1;
698 i = 0;
699 /* get references to the first two buffers */
700 FOR_EACH_BUFFER_REF(br, btrn) {
701 brs[i] = br;
702 szs[i] = btr_get_buffer_by_reference(brs[i], bufs + i);
703 i++;
704 if (i == 2)
705 break;
706 }
707 /* make a new btrb that combines the two buffers and a br to it. */
708 sz = szs[0] + szs[1];
709 buf = para_malloc(sz);
710 PARA_DEBUG_LOG("%s: memory merging input buffers: (%zu, %zu) -> %zu\n",
711 btrn->name, szs[0], szs[1], sz);
712 memcpy(buf, bufs[0], szs[0]);
713 memcpy(buf + szs[0], bufs[1], szs[1]);
714
715 br = para_calloc(sizeof(*br));
716 br->btrb = new_btrb(buf, sz);
717 br->btrb->refcount = 1;
718
719 /* replace the first two refs by the new one */
720 btr_drop_buffer_reference(brs[0]);
721 btr_drop_buffer_reference(brs[1]);
722 para_list_add(&br->node, &btrn->input_queue);
723 return 2;
724 }
725
726 void btr_merge(struct btr_node *btrn, size_t dest_size)
727 {
728 if (need_buffer_pool_merge(btrn))
729 return merge_input_pool(btrn, dest_size);
730 for (;;) {
731 char *buf;
732 size_t len = btr_next_buffer(btrn, &buf);
733 if (len >= dest_size)
734 return;
735 PARA_DEBUG_LOG("input size = %zu < %zu = dest\n", len, dest_size);
736 if (merge_input(btrn) < 2)
737 return;
738 }
739 }
740
741 bool btr_eof(struct btr_node *btrn)
742 {
743 char *buf;
744 size_t len = btr_next_buffer(btrn, &buf);
745
746 return (len == 0 && btr_no_parent(btrn));
747 }
748
749 void log_tree_recursively(struct btr_node *btrn, int loglevel, int depth)
750 {
751 struct btr_node *ch;
752 const char spaces[] = " ", *space = spaces + 16 - depth;
753
754 if (depth > 16)
755 return;
756 para_log(loglevel, "%s%s\n", space, btrn->name);
757 FOR_EACH_CHILD(ch, btrn)
758 log_tree_recursively(ch, loglevel, depth + 1);
759 }
760
761 void btr_log_tree(struct btr_node *btrn, int loglevel)
762 {
763 return log_tree_recursively(btrn, loglevel, 0);
764 }
765
766 /*
767 * \return \a root if \a name is \p NULL.
768 */
769 struct btr_node *btr_search_node(const char *name, struct btr_node *root)
770 {
771 struct btr_node *ch;
772
773 if (!name)
774 return root;
775 if (!strcmp(root->name, name))
776 return root;
777 FOR_EACH_CHILD(ch, root) {
778 struct btr_node *result = btr_search_node(name, ch);
779 if (result)
780 return result;
781 }
782 return NULL;
783 }
784
785 /** 640K ought to be enough for everybody ;) */
786 #define BTRN_MAX_PENDING (640 * 1024)
787
788 int btr_node_status(struct btr_node *btrn, size_t min_iqs,
789 enum btr_node_type type)
790 {
791 size_t iqs;
792
793 assert(btrn);
794 if (type != BTR_NT_LEAF) {
795 if (btr_no_children(btrn))
796 return -E_BTR_NO_CHILD;
797 if (btr_bytes_pending(btrn) > BTRN_MAX_PENDING)
798 return 0;
799 }
800 if (type != BTR_NT_ROOT) {
801 if (btr_eof(btrn))
802 return -E_BTR_EOF;
803 iqs = btr_get_input_queue_size(btrn);
804 if (iqs == 0) /* we have a parent, because not eof */
805 return 0;
806 if (iqs < min_iqs && !btr_no_parent(btrn))
807 return 0;
808 }
809 return 1;
810 }
811
812 void btr_get_node_start(struct btr_node *btrn, struct timeval *tv)
813 {
814 *tv = btrn->start;
815 }