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
;
123 if (list_empty(&btrn
->children
)) {
127 btrb
= new_btrb(buf
, size
);
128 add_btrb_to_children(btrb
, btrn
, 0);
131 static void btr_pushdown_br(struct btr_buffer_reference
*br
, struct btr_node
*btrn
)
133 add_btrb_to_children(br
->btrb
, btrn
, br
->consumed
);
134 btr_drop_buffer_reference(br
);
137 void btr_pushdown(struct btr_node
*btrn
)
139 struct btr_buffer_reference
*br
, *tmp
;
141 FOR_EACH_BUFFER_REF_SAFE(br
, tmp
, btrn
)
142 btr_pushdown_br(br
, btrn
);
145 int btr_pushdown_one(struct btr_node
*btrn
)
147 struct btr_buffer_reference
*br
;
149 if (list_empty(&btrn
->input_queue
))
151 br
= list_first_entry(&btrn
->input_queue
, struct btr_buffer_reference
, node
);
152 btr_pushdown_br(br
, btrn
);
156 /* Return true if this node has no children. */
157 bool btr_no_children(struct btr_node
*btrn
)
159 return list_empty(&btrn
->children
);
162 bool btr_no_parent(struct btr_node
*btrn
)
164 return !btrn
->parent
;
167 bool btr_inplace_ok(struct btr_node
*btrn
)
171 return list_is_singular(&btrn
->parent
->children
);
174 static inline size_t br_available_bytes(struct btr_buffer_reference
*br
)
176 return br
->btrb
->size
- br
->consumed
;
179 size_t btr_get_buffer_by_reference(struct btr_buffer_reference
*br
, char **buf
)
181 *buf
= br
->btrb
->buf
+ br
->consumed
;
182 return br_available_bytes(br
);
186 * \return zero if the input buffer queue is empty.
188 size_t btr_next_buffer(struct btr_node
*btrn
, char **bufp
)
190 struct btr_buffer_reference
*br
;
192 if (list_empty(&btrn
->input_queue
)) {
196 br
= list_first_entry(&btrn
->input_queue
, struct btr_buffer_reference
, node
);
197 return btr_get_buffer_by_reference(br
, bufp
);
200 void btr_consume(struct btr_node
*btrn
, size_t numbytes
)
202 struct btr_buffer_reference
*br
;
204 assert(!list_empty(&btrn
->input_queue
));
205 br
= list_first_entry(&btrn
->input_queue
, struct btr_buffer_reference
, node
);
206 assert(br
->consumed
+ numbytes
<= br
->btrb
->size
);
207 br
->consumed
+= numbytes
;
208 if (br
->consumed
== br
->btrb
->size
)
209 btr_drop_buffer_reference(br
);
212 static void flush_input_queue(struct btr_node
*btrn
)
214 struct btr_buffer_reference
*br
, *tmp
;
215 FOR_EACH_BUFFER_REF_SAFE(br
, tmp
, btrn
)
216 btr_drop_buffer_reference(br
);
219 void btr_free_node(struct btr_node
*btrn
)
227 void btr_remove_node(struct btr_node
*btrn
)
233 PARA_NOTICE_LOG("removing btr node %s from buffer tree\n", btrn
->name
);
234 FOR_EACH_CHILD(ch
, btrn
)
236 flush_input_queue(btrn
);
238 list_del(&btrn
->node
);
241 size_t btr_get_input_queue_size(struct btr_node
*btrn
)
243 struct btr_buffer_reference
*br
;
246 FOR_EACH_BUFFER_REF(br
, btrn
) {
247 //PARA_CRIT_LOG("size: %zu\n", size);
248 size
+= br_available_bytes(br
);
253 void btr_splice_out_node(struct btr_node
*btrn
)
255 struct btr_node
*ch
, *tmp
;
258 PARA_NOTICE_LOG("splicing out %s\n", btrn
->name
);
261 list_del(&btrn
->node
);
262 FOR_EACH_CHILD_SAFE(ch
, tmp
, btrn
) {
263 PARA_INFO_LOG("parent(%s): %s\n", ch
->name
,
264 btrn
->parent
? btrn
->parent
->name
: "NULL");
265 ch
->parent
= btrn
->parent
;
267 list_move(&ch
->node
, &btrn
->parent
->children
);
269 assert(list_empty(&btrn
->children
));
273 * Return the size of the largest input queue.
275 * Iterates over all children of the given node.
277 size_t btr_bytes_pending(struct btr_node
*btrn
)
282 FOR_EACH_CHILD(ch
, btrn
) {
283 size_t size
= btr_get_input_queue_size(ch
);
284 max_size
= PARA_MAX(max_size
, size
);
289 int btr_exec(struct btr_node
*btrn
, const char *command
, char **value_result
)
292 return -ERRNO_TO_PARA_ERROR(EINVAL
);
294 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
295 return btrn
->execute(btrn
, command
, value_result
);
298 int btr_exec_up(struct btr_node
*btrn
, const char *command
, char **value_result
)
302 for (; btrn
; btrn
= btrn
->parent
) {
303 struct btr_node
*parent
= btrn
->parent
;
305 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
306 if (!parent
->execute
)
308 PARA_INFO_LOG("parent: %s, cmd: %s\n", parent
->name
, command
);
309 ret
= parent
->execute(parent
, command
, value_result
);
310 if (ret
== -ERRNO_TO_PARA_ERROR(ENOTSUP
))
314 if (value_result
&& *value_result
)
315 PARA_NOTICE_LOG("%s(%s): %s\n", command
, parent
->name
,
319 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
322 void *btr_context(struct btr_node
*btrn
)
324 return btrn
->context
;
328 * Merge the first two input buffers into one.
330 * This is a quite expensive operation.
332 * \return The number of buffers that have been available (zero, one or two).
334 static int merge_input(struct btr_node
*btrn
)
336 struct btr_buffer_reference
*brs
[2], *br
;
341 if (list_empty(&btrn
->input_queue
))
343 if (list_is_singular(&btrn
->input_queue
))
346 /* get references to the first two buffers */
347 FOR_EACH_BUFFER_REF(br
, btrn
) {
349 szs
[i
] = btr_get_buffer_by_reference(brs
[i
], bufs
+ i
);
354 /* make a new btrb that combines the two buffers and a br to it. */
355 sz
= szs
[0] + szs
[1];
356 //PARA_CRIT_LOG("merging input buffers: (%zu, %zu) -> %zu\n",
357 // szs[0], szs[1], sz);
358 buf
= para_malloc(sz
);
359 /* TODO: Avoid this memcopy by introducing btr buffer pool. */
360 memcpy(buf
, bufs
[0], szs
[0]);
361 memcpy(buf
+ szs
[0], bufs
[1], szs
[1]);
363 br
= para_malloc(sizeof(*br
));
364 br
->btrb
= new_btrb(buf
, sz
);
365 br
->btrb
->refcount
= 1;
368 /* replace the first two refs by the new one */
369 btr_drop_buffer_reference(brs
[0]);
370 btr_drop_buffer_reference(brs
[1]);
371 para_list_add(&br
->node
, &btrn
->input_queue
);
375 void btr_merge(struct btr_node
*btrn
, size_t dest_size
)
379 size_t len
= btr_next_buffer(btrn
, &buf
);
380 if (len
>= dest_size
)
382 if (merge_input(btrn
) < 2)
387 bool btr_eof(struct btr_node
*btrn
)
390 size_t len
= btr_next_buffer(btrn
, &buf
);
392 return (len
== 0 && btr_no_parent(btrn
));
395 void log_tree_recursively(struct btr_node
*btrn
, int loglevel
, int depth
)
398 const char spaces
[] = " ", *space
= spaces
+ 16 - depth
;
402 para_log(loglevel
, "%s%s\n", space
, btrn
->name
);
403 FOR_EACH_CHILD(ch
, btrn
)
404 log_tree_recursively(ch
, loglevel
, depth
+ 1);
407 void btr_log_tree(struct btr_node
*btrn
, int loglevel
)
409 return log_tree_recursively(btrn
, loglevel
, 0);
412 /** 640K ought to be enough for everybody ;) */
413 #define BTRN_MAX_PENDING (640 * 1024)
415 int btr_node_status(struct btr_node
*btrn
, size_t min_iqs
)
421 if (btr_bytes_pending(btrn
) > BTRN_MAX_PENDING
)
423 iqs
= btr_get_input_queue_size(btrn
);
424 if (iqs
== 0) /* we have a parent, because not eof */
426 if (iqs
< min_iqs
&& !btr_no_parent(btrn
))