1 #include <u.h>
2 #include <libc.h>
3 #include <draw.h>
4 #include <thread.h>
5 #include <cursor.h>
6 #include <mouse.h>
7 #include <keyboard.h>
8 #include <frame.h>
9 #include <fcall.h>
10 #include "dat.h"
11 #include "fns.h"
12 
13 static Channel*	ctimer;	/* chan(Timer*)[100] */
14 static Timer *timer;
15 
16 static
17 uint
18 msec(void)
19 {
20 	return nsec()/1000000;
21 }
22 
23 void
24 timerstop(Timer *t)
25 {
26 	t->next = timer;
27 	timer = t;
28 }
29 
30 void
31 timercancel(Timer *t)
32 {
33 	t->cancel = TRUE;
34 }
35 
36 static
37 void
38 timerproc(void *a)
39 {
40 	int i, nt, na, dt, del;
41 	Timer **t, *x;
42 	uint old, new;
43 
44 	USED(a);
45 	rfork(RFFDG);
46 	threadsetname("TIMERPROC");
47 	t = nil;
48 	na = 0;
49 	nt = 0;
50 	old = msec();
51 	for(;;){
52 		sleep(1);	/* will sleep minimum incr */
53 		new = msec();
54 		dt = new-old;
55 		old = new;
56 		if(dt < 0)	/* timer wrapped; go around, losing a tick */
57 			continue;
58 		for(i=0; i<nt; i++){
59 			x = t[i];
60 			x->dt -= dt;
61 			del = 0;
62 			if(x->cancel){
63 				timerstop(x);
64 				del = 1;
65 			}else if(x->dt <= 0){
66 				/*
67 				 * avoid possible deadlock if client is
68 				 * now sending on ctimer
69 				 */
70 				if(nbsendul(x->c, 0) > 0)
71 					del = 1;
72 			}
73 			if(del){
74 				memmove(&t[i], &t[i+1], (nt-i-1)*sizeof t[0]);
75 				--nt;
76 				--i;
77 			}
78 		}
79 		if(nt == 0){
80 			x = recvp(ctimer);
81 	gotit:
82 			if(nt == na){
83 				na += 10;
84 				t = realloc(t, na*sizeof(Timer*));
85 				if(t == nil)
86 					abort();
87 			}
88 			t[nt++] = x;
89 			old = msec();
90 		}
91 		if(nbrecv(ctimer, &x) > 0)
92 			goto gotit;
93 	}
94 }
95 
96 void
97 timerinit(void)
98 {
99 	ctimer = chancreate(sizeof(Timer*), 100);
100 	proccreate(timerproc, nil, STACK);
101 }
102 
103 /*
104  * timeralloc() and timerfree() don't lock, so can only be
105  * called from the main proc.
106  */
107 
108 Timer*
109 timerstart(int dt)
110 {
111 	Timer *t;
112 
113 	t = timer;
114 	if(t)
115 		timer = timer->next;
116 	else{
117 		t = emalloc(sizeof(Timer));
118 		t->c = chancreate(sizeof(int), 0);
119 	}
120 	t->next = nil;
121 	t->dt = dt;
122 	t->cancel = FALSE;
123 	sendp(ctimer, t);
124 	return t;
125 }