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)
45 #define FOR_EACH_BUFFER_REF(_br, _btrn) \
46 list_for_each_entry((_br), &(_btrn)->input_queue, node)
47 #define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
48 list_for_each_entry_safe((_br), (_tmp), &(_btrn)->input_queue, node)
50 struct btr_node
*btr_new_node(char *name
, struct btr_node
*parent
,
51 btr_command_handler handler
, void *context
)
53 struct btr_node
*btrn
= para_malloc(sizeof(*btrn
));
55 btrn
->name
= para_strdup(name
);
56 btrn
->parent
= parent
;
57 btrn
->execute
= handler
;
58 btrn
->context
= context
;
60 list_add_tail(&btrn
->node
, &parent
->children
);
61 INIT_LIST_HEAD(&btrn
->children
);
62 INIT_LIST_HEAD(&btrn
->input_queue
);
67 * Allocate a new btr buffer.
69 * The freshly allocated buffer will have a zero refcount.
71 static struct btr_buffer
*new_btrb(char *buf
, size_t size
)
73 struct btr_buffer
*btrb
= para_malloc(sizeof(*btrb
));
82 * Deallocate the reference, release the resources if refcount drops to zero.
84 static void btr_drop_buffer_reference(struct btr_buffer_reference
*br
)
86 struct btr_buffer
*btrb
= br
->btrb
;
88 //PARA_CRIT_LOG("dropping buffer reference %p\n", br);
92 if (btrb
->refcount
== 0) {
98 static void add_btrb_to_children(struct btr_buffer
*btrb
,
99 struct btr_node
*btrn
, size_t consumed
)
103 FOR_EACH_CHILD(ch
, btrn
) {
104 struct btr_buffer_reference
*br
= para_malloc(sizeof(*br
));
106 br
->consumed
= consumed
;
107 list_add_tail(&br
->node
, &ch
->input_queue
);
112 void btr_add_output(char *buf
, size_t size
, struct btr_node
*btrn
)
114 struct btr_buffer
*btrb
;
116 btrb
= new_btrb(buf
, size
);
117 add_btrb_to_children(btrb
, btrn
, 0);
120 static void btr_pushdown_br(struct btr_buffer_reference
*br
, struct btr_node
*btrn
)
122 add_btrb_to_children(br
->btrb
, btrn
, br
->consumed
);
123 btr_drop_buffer_reference(br
);
126 void btr_pushdown(struct btr_node
*btrn
)
128 struct btr_buffer_reference
*br
, *tmp
;
130 FOR_EACH_BUFFER_REF_SAFE(br
, tmp
, btrn
)
131 btr_pushdown_br(br
, btrn
);
134 /* Return true if this node has no children. */
135 bool btr_no_children(struct btr_node
*btrn
)
137 return list_empty(&btrn
->children
);
140 bool btr_no_parent(struct btr_node
*btrn
)
142 return !btrn
->parent
;
145 bool btr_inplace_ok(struct btr_node
*btrn
)
149 return list_is_singular(&btrn
->parent
->children
);
152 static inline size_t br_available_bytes(struct btr_buffer_reference
*br
)
154 return br
->btrb
->size
- br
->consumed
;
157 size_t btr_get_buffer_by_reference(struct btr_buffer_reference
*br
, char **buf
)
159 *buf
= br
->btrb
->buf
+ br
->consumed
;
160 return br_available_bytes(br
);
163 size_t btr_next_buffer(struct btr_node
*btrn
, char **bufp
)
165 struct btr_buffer_reference
*br
;
167 if (list_empty(&btrn
->input_queue
)) {
171 br
= list_first_entry(&btrn
->input_queue
, struct btr_buffer_reference
, node
);
172 return btr_get_buffer_by_reference(br
, bufp
);
175 void btr_consume(struct btr_node
*btrn
, size_t numbytes
)
177 struct btr_buffer_reference
*br
;
179 assert(!list_empty(&btrn
->input_queue
));
180 br
= list_first_entry(&btrn
->input_queue
, struct btr_buffer_reference
, node
);
181 assert(br
->consumed
+ numbytes
<= br
->btrb
->size
);
182 br
->consumed
+= numbytes
;
183 if (br
->consumed
== br
->btrb
->size
)
184 btr_drop_buffer_reference(br
);
187 static void flush_input_queue(struct btr_node
*btrn
)
189 struct btr_buffer_reference
*br
, *tmp
;
190 FOR_EACH_BUFFER_REF_SAFE(br
, tmp
, btrn
)
191 btr_drop_buffer_reference(br
);
194 void btr_del_node(struct btr_node
*btrn
)
200 PARA_NOTICE_LOG("deleting %s\n", btrn
->name
);
201 FOR_EACH_CHILD(ch
, btrn
)
203 flush_input_queue(btrn
);
205 list_del(&btrn
->node
);
210 size_t btr_get_input_queue_size(struct btr_node
*btrn
)
212 struct btr_buffer_reference
*br
;
215 FOR_EACH_BUFFER_REF(br
, btrn
) {
216 //PARA_CRIT_LOG("size: %zu\n", size);
217 size
+= br_available_bytes(br
);
222 int btr_splice_out_node(struct btr_node
*btrn
)
227 return -ERRNO_TO_PARA_ERROR(EINVAL
);
228 if (btr_get_input_queue_size(btrn
) != 0)
229 return -ERRNO_TO_PARA_ERROR(EINVAL
);
230 PARA_NOTICE_LOG("splicing out %s\n", btrn
->name
);
232 list_del(&btrn
->node
);
233 FOR_EACH_CHILD(ch
, btrn
)
234 ch
->parent
= btrn
->parent
;
241 * Return the size of the largest input queue.
243 * Iterates over all children of the given node.
245 size_t btr_bytes_pending(struct btr_node
*btrn
)
250 FOR_EACH_CHILD(ch
, btrn
) {
251 size_t size
= btr_get_input_queue_size(ch
);
252 max_size
= PARA_MAX(max_size
, size
);
257 int btr_exec(struct btr_node
*btrn
, const char *command
, char **value_result
)
260 return -ERRNO_TO_PARA_ERROR(EINVAL
);
262 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
263 return btrn
->execute(btrn
, command
, value_result
);
266 int btr_exec_up(struct btr_node
*btrn
, const char *command
, char **value_result
)
270 for (; btrn
; btrn
= btrn
->parent
) {
271 struct btr_node
*parent
= btrn
->parent
;
272 PARA_CRIT_LOG("parent: %p\n", parent
);
274 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
275 if (!parent
->execute
)
277 ret
= parent
->execute(parent
, command
, value_result
);
278 if (ret
== -ERRNO_TO_PARA_ERROR(ENOTSUP
))
283 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
286 void *btr_context(struct btr_node
*btrn
)
288 return btrn
->context
;