code: plan9front

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mouse: Make /dev/mousein readable to get mouse status without blocking

There is currently no way to get the current mouse position
and button states without blocking.

--- a/sys/man/3/mouse

+++ b/sys/man/3/mouse

@@ -56,23 +56,30 @@

 .B mousein

 file are processed as if they were generated by the

 mouse hardware itself,

-as extra mouse events to be processed and passed back via

-the

+as extra mouse events to be processed and passed back via the

 .B mouse

 file.

+Reading the

+.B mousein

+file returns the current mouse status without waiting.

 The

 .B mousein

 file, which may be opened

-only by the host owner, is intended for controlling devices, such as USB mice,

+only by the host owner, is intended for controlling devices,

+such as USB mice and tablets,

 that are managed by user-level software.

 Each event should consist of

 the letter

 .B m

-followed by delta

-.IR x ,

-delta

-.IR y ,

+(for relative delta coordinates)

+or

+.B A

+(for absolute screen coordinates)

+followed by the

+.I x

 and

+.I y

+coordinates and

 .IR buttons

 as space-separated decimal numbers.

 .PP

--- a/sys/src/9/port/devmouse.c

+++ b/sys/src/9/port/devmouse.c

@@ -88,7 +88,7 @@

 	".",	{Qdir, 0, QTDIR},	0,			DMDIR|0555,

 	"cursor",	{Qcursor},	0,			0666,

 	"mouse",	{Qmouse},	0,			0666,

-	"mousein",	{Qmousein},	0,			0220,

+	"mousein",	{Qmousein},	0,			0660,

 	"mousectl",	{Qmousectl},	0,			0220,

 };

@@ -207,7 +207,9 @@

 		return;

 	switch((ulong)c->qid.path){

 	case Qmousein:

+		ilock(&mouse);

 		mouse.inbuttons &= ~((Mousestate*)c->aux)->buttons;

+		iunlock(&mouse);

 		free(c->aux);	/* Mousestate */

 		c->aux = nil;

 		return;

@@ -232,6 +234,7 @@

 	Cursor curs;

 	Mousestate m;

 	int b;

+	char t;

 	p = va;

 	switch((ulong)c->qid.path){

@@ -272,23 +275,39 @@

 			m = mouse.Mousestate;

 		iunlock(&mouse);

+		if(0){

+	case Qmousein:

+			if(offset != 0)

+				return 0;

+

+			ilock(&mouse);

+			m = mouse.Mousestate;

+			iunlock(&mouse);

+

+			t = 'm';

+		} else {

+			/* Qmouse */

+			mouse.lastcounter = m.counter;

+			if(mouse.resize){

+				mouse.resize = 0;

+				t = 'r';

+			} else {

+				t = 'm';

+			}

+		}

+

 		b = buttonmap[m.buttons&7];

 		/* put buttons 4 and 5 back in */

 		b |= m.buttons & (3<<3);

+

 		if (scrollswap)

 			if (b == 8)

 				b = 16;

 			else if (b == 16)

 				b = 8;

-		sprint(buf, "m%11d %11d %11d %11ld ",

-			m.xy.x, m.xy.y, b, m.msec);

-		mouse.lastcounter = m.counter;

-		if(mouse.resize){

-			mouse.resize = 0;

-			buf[0] = 'r';

-		}

-

+		snprint(buf, sizeof(buf), "%c%11d %11d %11d %11ld ",

+			t, m.xy.x, m.xy.y, b, m.msec);

 		if(n > 1+4*12)

 			n = 1+4*12;

 		memmove(va, buf, n);

@@ -446,8 +465,11 @@

 		m->msec = msec;

 		b ^= m->buttons;

 		m->buttons ^= b;

+

+		ilock(&mouse);

 		mouse.inbuttons = (m->buttons & b) | (mouse.inbuttons & ~b);

 		b = mouse.buttons & ~b;

+		iunlock(&mouse);

 		/* include wheel */

 		b &= ~(8|16);