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
;
41 #define FOR_EACH_CHILD(_tn, _btrn) list_for_each_entry((_tn), \
42 &((_btrn)->children), node)
44 #define FOR_EACH_BUFFER_REF(_br, _btrn) \
45 list_for_each_entry((_br), &(_btrn)->input_queue, node)
46 #define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
47 list_for_each_entry_safe((_br), (_tmp), &(_btrn)->input_queue, node)
49 struct btr_node
*btr_new_node(char *name
, struct btr_node
*parent
,
50 btr_command_handler handler
)
52 struct btr_node
*btrn
= para_malloc(sizeof(*btrn
));
54 btrn
->name
= para_strdup(name
);
55 btrn
->parent
= parent
;
56 btrn
->execute
= handler
;
58 list_add_tail(&btrn
->node
, &parent
->children
);
59 INIT_LIST_HEAD(&btrn
->children
);
60 INIT_LIST_HEAD(&btrn
->input_queue
);
65 * Allocate a new btr buffer.
67 * The freshly allocated buffer will have a zero refcount.
69 static struct btr_buffer
*new_btrb(char *buf
, size_t size
)
71 struct btr_buffer
*btrb
= para_malloc(sizeof(*btrb
));
80 * Deallocate the reference, release the resources if refcount drops to zero.
82 static void btr_drop_buffer_reference(struct btr_buffer_reference
*br
)
84 struct btr_buffer
*btrb
= br
->btrb
;
86 //PARA_CRIT_LOG("dropping buffer reference %p\n", br);
90 if (btrb
->refcount
== 0) {
96 static void add_btrb_to_children(struct btr_buffer
*btrb
, struct btr_node
*btrn
)
100 FOR_EACH_CHILD(ch
, btrn
) {
101 struct btr_buffer_reference
*br
= para_malloc(sizeof(*br
));
104 list_add_tail(&br
->node
, &ch
->input_queue
);
109 void btr_add_output(char *buf
, size_t size
, struct btr_node
*btrn
)
111 struct btr_buffer
*btrb
;
113 btrb
= new_btrb(buf
, size
);
114 add_btrb_to_children(btrb
, btrn
);
117 static void btr_pushdown_br(struct btr_buffer_reference
*br
, struct btr_node
*btrn
)
119 add_btrb_to_children(br
->btrb
, btrn
);
120 btr_drop_buffer_reference(br
);
123 void btr_pushdown(struct btr_node
*btrn
)
125 struct btr_buffer_reference
*br
, *tmp
;
127 FOR_EACH_BUFFER_REF_SAFE(br
, tmp
, btrn
)
128 btr_pushdown_br(br
, btrn
);
131 /* Return true if this node has no children. */
132 bool btr_no_children(struct btr_node
*btrn
)
134 return list_empty(&btrn
->children
);
137 bool btr_no_parent(struct btr_node
*btrn
)
139 return !btrn
->parent
;
142 bool btr_inplace_ok(struct btr_node
*btrn
)
146 return list_is_singular(&btrn
->parent
->children
);
149 static inline size_t br_available_bytes(struct btr_buffer_reference
*br
)
151 return br
->btrb
->size
- br
->consumed
;
154 size_t btr_get_buffer_by_reference(struct btr_buffer_reference
*br
, char **buf
)
156 *buf
= br
->btrb
->buf
+ br
->consumed
;
157 return br_available_bytes(br
);
160 size_t btr_next_buffer(struct btr_node
*btrn
, char **bufp
)
162 struct btr_buffer_reference
*br
;
164 if (list_empty(&btrn
->input_queue
)) {
168 br
= list_first_entry(&btrn
->input_queue
, struct btr_buffer_reference
, node
);
169 return btr_get_buffer_by_reference(br
, bufp
);
172 void btr_consume(struct btr_node
*btrn
, size_t numbytes
)
174 struct btr_buffer_reference
*br
;
176 assert(!list_empty(&btrn
->input_queue
));
177 br
= list_first_entry(&btrn
->input_queue
, struct btr_buffer_reference
, node
);
178 assert(br
->consumed
+ numbytes
<= br
->btrb
->size
);
179 br
->consumed
+= numbytes
;
180 if (br
->consumed
== br
->btrb
->size
)
181 btr_drop_buffer_reference(br
);
184 static void flush_input_queue(struct btr_node
*btrn
)
186 struct btr_buffer_reference
*br
, *tmp
;
187 FOR_EACH_BUFFER_REF_SAFE(br
, tmp
, btrn
)
188 btr_drop_buffer_reference(br
);
191 void btr_del_node(struct btr_node
*btrn
)
197 PARA_NOTICE_LOG("deleting %s\n", btrn
->name
);
198 FOR_EACH_CHILD(ch
, btrn
)
200 flush_input_queue(btrn
);
202 list_del(&btrn
->node
);
207 size_t btr_get_input_queue_size(struct btr_node
*btrn
)
209 struct btr_buffer_reference
*br
;
212 FOR_EACH_BUFFER_REF(br
, btrn
) {
213 //PARA_CRIT_LOG("size: %zu\n", size);
214 size
+= br_available_bytes(br
);
219 int btr_splice_out_node(struct btr_node
*btrn
)
224 return -ERRNO_TO_PARA_ERROR(EINVAL
);
225 if (btr_get_input_queue_size(btrn
) != 0)
226 return -ERRNO_TO_PARA_ERROR(EINVAL
);
227 PARA_NOTICE_LOG("splicing out %s\n", btrn
->name
);
229 list_del(&btrn
->node
);
230 FOR_EACH_CHILD(ch
, btrn
)
231 ch
->parent
= btrn
->parent
;
238 * Return the size of the largest input queue.
240 * Iterates over all children of the given node.
242 size_t btr_bytes_pending(struct btr_node
*btrn
)
247 FOR_EACH_CHILD(ch
, btrn
) {
248 size_t size
= btr_get_input_queue_size(ch
);
249 max_size
= PARA_MAX(max_size
, size
);
254 int btr_exec(struct btr_node
*btrn
, const char *command
, char **value_result
)
257 return -ERRNO_TO_PARA_ERROR(EINVAL
);
259 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
260 return btrn
->execute(command
, value_result
);
263 int btr_exec_up(struct btr_node
*btrn
, const char *command
, char **value_result
)
267 for (; btrn
; btrn
= btrn
->parent
) {
268 struct btr_node
*parent
= btrn
->parent
;
269 PARA_CRIT_LOG("parent: %p\n", parent
);
271 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
272 if (!parent
->execute
)
274 ret
= parent
->execute(command
, value_result
);
275 if (ret
== -ERRNO_TO_PARA_ERROR(ENOTSUP
))
280 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);