7 #include "buffer_tree.h"
14 /** The number of references to this buffer. */
18 struct btr_buffer_reference {
19 struct btr_buffer *btrb;
21 /* Each buffer reference belongs to the buffer queue list of some buffer tree node. */
22 struct list_head node;
27 struct btr_node *parent;
28 /* The position of this btr node in the buffer tree. */
29 struct list_head node;
30 /* The children nodes of this btr node are linked together in a list. */
31 struct list_head children;
33 * The input queue is a list of references to btr buffers. Each item on
34 * the list represents an input buffer which has not been completely
35 * used by this btr node.
37 struct list_head input_queue;
38 btr_command_handler execute;
42 #define FOR_EACH_CHILD(_tn, _btrn) list_for_each_entry((_tn), \
43 &((_btrn)->children), node)
44 #define FOR_EACH_CHILD_SAFE(_tn, _tmp, _btrn) \
45 list_for_each_entry_safe((_tn), (_tmp), &((_btrn)->children), node)
47 #define FOR_EACH_BUFFER_REF(_br, _btrn) \
48 list_for_each_entry((_br), &(_btrn)->input_queue, node)
49 #define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
50 list_for_each_entry_safe((_br), (_tmp), &(_btrn)->input_queue, node)
52 struct btr_node *btr_new_node(const char *name, struct btr_node *parent,
53 btr_command_handler handler, void *context)
55 struct btr_node *btrn = para_malloc(sizeof(*btrn));
57 btrn->name = para_strdup(name);
58 btrn->parent = parent;
59 btrn->execute = handler;
60 btrn->context = context;
62 list_add_tail(&btrn->node, &parent->children);
63 INIT_LIST_HEAD(&btrn->children);
64 INIT_LIST_HEAD(&btrn->input_queue);
66 PARA_INFO_LOG("added %s as child of %s\n", name, parent->name);
68 PARA_INFO_LOG("added %s as btr root\n", name);
73 * Allocate a new btr buffer.
75 * The freshly allocated buffer will have a zero refcount.
77 static struct btr_buffer *new_btrb(char *buf, size_t size)
79 struct btr_buffer *btrb = para_malloc(sizeof(*btrb));
88 * Deallocate the reference, release the resources if refcount drops to zero.
90 static void btr_drop_buffer_reference(struct btr_buffer_reference *br)
92 struct btr_buffer *btrb = br->btrb;
94 //PARA_CRIT_LOG("dropping buffer reference %p\n", br);
98 if (btrb->refcount == 0) {
104 static void add_btrb_to_children(struct btr_buffer *btrb,
105 struct btr_node *btrn, size_t consumed)
109 FOR_EACH_CHILD(ch, btrn) {
110 struct btr_buffer_reference *br = para_malloc(sizeof(*br));
112 br->consumed = consumed;
113 list_add_tail(&br->node, &ch->input_queue);
118 void btr_add_output(char *buf, size_t size, struct btr_node *btrn)
120 struct btr_buffer *btrb;
122 btrb = new_btrb(buf, size);
123 add_btrb_to_children(btrb, btrn, 0);
126 static void btr_pushdown_br(struct btr_buffer_reference *br, struct btr_node *btrn)
128 add_btrb_to_children(br->btrb, btrn, br->consumed);
129 btr_drop_buffer_reference(br);
132 void btr_pushdown(struct btr_node *btrn)
134 struct btr_buffer_reference *br, *tmp;
136 FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn)
137 btr_pushdown_br(br, btrn);
140 int btr_pushdown_one(struct btr_node *btrn)
142 struct btr_buffer_reference *br;
144 if (list_empty(&btrn->input_queue))
146 br = list_first_entry(&btrn->input_queue, struct btr_buffer_reference, node);
147 btr_pushdown_br(br, btrn);
151 /* Return true if this node has no children. */
152 bool btr_no_children(struct btr_node *btrn)
154 return list_empty(&btrn->children);
157 bool btr_no_parent(struct btr_node *btrn)
159 return !btrn->parent;
162 bool btr_inplace_ok(struct btr_node *btrn)
166 return list_is_singular(&btrn->parent->children);
169 static inline size_t br_available_bytes(struct btr_buffer_reference *br)
171 return br->btrb->size - br->consumed;
174 size_t btr_get_buffer_by_reference(struct btr_buffer_reference *br, char **buf)
176 *buf = br->btrb->buf + br->consumed;
177 return br_available_bytes(br);
181 * \return zero if the input buffer queue is empty.
183 size_t btr_next_buffer(struct btr_node *btrn, char **bufp)
185 struct btr_buffer_reference *br;
187 if (list_empty(&btrn->input_queue)) {
191 br = list_first_entry(&btrn->input_queue, struct btr_buffer_reference, node);
192 return btr_get_buffer_by_reference(br, bufp);
195 void btr_consume(struct btr_node *btrn, size_t numbytes)
197 struct btr_buffer_reference *br;
199 assert(!list_empty(&btrn->input_queue));
200 br = list_first_entry(&btrn->input_queue, struct btr_buffer_reference, node);
201 assert(br->consumed + numbytes <= br->btrb->size);
202 br->consumed += numbytes;
203 if (br->consumed == br->btrb->size)
204 btr_drop_buffer_reference(br);
207 static void flush_input_queue(struct btr_node *btrn)
209 struct btr_buffer_reference *br, *tmp;
210 FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn)
211 btr_drop_buffer_reference(br);
214 void btr_del_node(struct btr_node *btrn)
220 PARA_NOTICE_LOG("deleting %s\n", btrn->name);
221 FOR_EACH_CHILD(ch, btrn)
223 flush_input_queue(btrn);
225 list_del(&btrn->node);
230 size_t btr_get_input_queue_size(struct btr_node *btrn)
232 struct btr_buffer_reference *br;
235 FOR_EACH_BUFFER_REF(br, btrn) {
236 //PARA_CRIT_LOG("size: %zu\n", size);
237 size += br_available_bytes(br);
242 void btr_splice_out_node(struct btr_node *btrn)
244 struct btr_node *ch, *tmp;
247 PARA_NOTICE_LOG("splicing out %s\n", btrn->name);
250 list_del(&btrn->node);
251 FOR_EACH_CHILD_SAFE(ch, tmp, btrn) {
252 PARA_INFO_LOG("parent(%s): %s\n", ch->name,
253 btrn->parent? btrn->parent->name : "NULL");
254 ch->parent = btrn->parent;
256 list_move(&ch->node, &btrn->parent->children);
258 assert(list_empty(&btrn->children));
264 * Return the size of the largest input queue.
266 * Iterates over all children of the given node.
268 size_t btr_bytes_pending(struct btr_node *btrn)
273 FOR_EACH_CHILD(ch, btrn) {
274 size_t size = btr_get_input_queue_size(ch);
275 max_size = PARA_MAX(max_size, size);
280 int btr_exec(struct btr_node *btrn, const char *command, char **value_result)
283 return -ERRNO_TO_PARA_ERROR(EINVAL);
285 return -ERRNO_TO_PARA_ERROR(ENOTSUP);
286 return btrn->execute(btrn, command, value_result);
289 int btr_exec_up(struct btr_node *btrn, const char *command, char **value_result)
293 for (; btrn; btrn = btrn->parent) {
294 struct btr_node *parent = btrn->parent;
296 return -ERRNO_TO_PARA_ERROR(ENOTSUP);
297 if (!parent->execute)
299 PARA_INFO_LOG("parent: %s, cmd: %s\n", parent->name, command);
300 ret = parent->execute(parent, command, value_result);
301 if (ret == -ERRNO_TO_PARA_ERROR(ENOTSUP))
305 if (value_result && *value_result)
306 PARA_NOTICE_LOG("%s(%s): %s\n", command, parent->name,
310 return -ERRNO_TO_PARA_ERROR(ENOTSUP);
313 void *btr_context(struct btr_node *btrn)
315 return btrn->context;
319 * Merge the first two input buffers into one.
321 * This is a quite expensive operation.
323 * \return The number of buffers that have been available (zero, one or two).
325 static int merge_input(struct btr_node *btrn)
327 struct btr_buffer_reference *brs[2], *br;
332 if (list_empty(&btrn->input_queue))
334 if (list_is_singular(&btrn->input_queue))
337 /* get references to the first two buffers */
338 FOR_EACH_BUFFER_REF(br, btrn) {
340 szs[i] = btr_get_buffer_by_reference(brs[i], bufs + i);
345 /* make a new btrb that combines the two buffers and a br to it. */
346 sz = szs[0] + szs[1];
347 //PARA_CRIT_LOG("merging input buffers: (%zu, %zu) -> %zu\n",
348 // szs[0], szs[1], sz);
349 buf = para_malloc(sz);
350 /* TODO: Avoid this memcopy by introducing btr buffer pool. */
351 memcpy(buf, bufs[0], szs[0]);
352 memcpy(buf + szs[0], bufs[1], szs[1]);
354 br = para_malloc(sizeof(*br));
355 br->btrb = new_btrb(buf, sz);
356 br->btrb->refcount = 1;
359 /* replace the first two refs by the new one */
360 btr_drop_buffer_reference(brs[0]);
361 btr_drop_buffer_reference(brs[1]);
362 para_list_add(&br->node, &btrn->input_queue);
366 void btr_merge(struct btr_node *btrn, size_t dest_size)
370 size_t len = btr_next_buffer(btrn, &buf);
371 if (len >= dest_size)
373 if (merge_input(btrn) < 2)
378 bool btr_eof(struct btr_node *btrn)
381 size_t len = btr_next_buffer(btrn, &buf);
383 return (len == 0 && btr_no_parent(btrn));
386 void log_tree_recursively(struct btr_node *btrn, int loglevel, int depth)
389 const char spaces[] = " ", *space = spaces + 16 - depth;
393 para_log(loglevel, "%s%s\n", space, btrn->name);
394 FOR_EACH_CHILD(ch, btrn)
395 log_tree_recursively(ch, loglevel, depth + 1);
398 void btr_log_tree(struct btr_node *btrn, int loglevel)
400 return log_tree_recursively(btrn, loglevel, 0);