1 #include <u.h>
2 #include <libc.h>
3 #include <venti.h>
4 #include "queue.h"
5 
6 typedef struct Qel Qel;
7 struct Qel
8 {
9 	Qel *next;
10 	void *p;
11 };
12 
13 struct Queue
14 {
15 	int hungup;
16 	QLock lk;
17 	Rendez r;
18 	Qel *head;
19 	Qel *tail;
20 };
21 
22 Queue*
23 _vtqalloc(void)
24 {
25 	Queue *q;
26 
27 	q = vtmallocz(sizeof(Queue));
28 	q->r.l = &q->lk;
29 	return q;
30 }
31 
32 int
33 _vtqsend(Queue *q, void *p)
34 {
35 	Qel *e;
36 
37 	e = vtmalloc(sizeof(Qel));
38 	qlock(&q->lk);
39 	if(q->hungup){
40 		werrstr("hungup queue");
41 		qunlock(&q->lk);
42 		return -1;
43 	}
44 	e->p = p;
45 	e->next = nil;
46 	if(q->head == nil)
47 		q->head = e;
48 	else
49 		q->tail->next = e;
50 	q->tail = e;
51 	rwakeup(&q->r);
52 	qunlock(&q->lk);
53 	return 0;
54 }
55 
56 void*
57 _vtqrecv(Queue *q)
58 {
59 	void *p;
60 	Qel *e;
61 
62 	qlock(&q->lk);
63 	while(q->head == nil && !q->hungup)
64 		rsleep(&q->r);
65 	if(q->hungup){
66 		qunlock(&q->lk);
67 		return nil;
68 	}
69 	e = q->head;
70 	q->head = e->next;
71 	qunlock(&q->lk);
72 	p = e->p;
73 	vtfree(e);
74 	return p;
75 }
76 
77 void*
78 _vtnbqrecv(Queue *q)
79 {
80 	void *p;
81 	Qel *e;
82 
83 	qlock(&q->lk);
84 	if(q->head == nil){
85 		qunlock(&q->lk);
86 		return nil;
87 	}
88 	e = q->head;
89 	q->head = e->next;
90 	qunlock(&q->lk);
91 	p = e->p;
92 	vtfree(e);
93 	return p;
94 }
95 
96 void
97 _vtqhangup(Queue *q)
98 {
99 	qlock(&q->lk);
100 	q->hungup = 1;
101 	rwakeupall(&q->r);
102 	qunlock(&q->lk);
103 }