main.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#include <u.h>
#include <libc.h>
#include <draw.h>
#include <event.h>
#include <bio.h>
#include <keyboard.h>
#include "cons.h"

enum{
	Ehost		= 4,
};

char	*menutext2[] = {
	"backup",
	"forward",
	"reset",
	"clear",
	"send",
	"page",
	0
};

char	*menutext3[] = {
	"24x80",
	"crnl",
	"nl",
	"raw",
	"exit",
	0
};

/* variables associated with the screen */

int	x, y;	/* character positions */
char	*backp;
int	backc;
int	atend;
int	nbacklines;
int	xmax, ymax;
int	blocked;
int	resize_flag;
int	pagemode;
int	olines;
int	peekc;
int	cursoron = 1;
Menu	menu2;
Menu	menu3;
char	*histp;
char	hist[HISTSIZ];
int	yscrmin, yscrmax;
int	attr, defattr;
int	wctlout;

Image	*bordercol;
Image	*cursback;
Image	*colors[8];
Image	*hicolors[8];
Image	*red;
Image	*fgcolor;
Image	*bgcolor;
Image	*fgdefault;
Image	*bgdefault;

uint rgbacolors[8] = {
	0x000000FF,	/* black */
	0xAA0000FF,	/* red */
	0x00AA00FF,	/* green */
	0xFF5500FF,	/* brown */
	0x0000FFFF,	/* blue */
	0xAA00AAFF,	/* purple */
	0x00AAAAFF,	/* cyan */
	0x7F7F7FFF,	/* white */
};

ulong rgbahicolors[8] = {
	0x555555FF,	/* light black aka grey */
	0xFF5555FF,	/* light red */
	0x55FF55FF,	/* light green */
	0xFFFF55FF,	/* light brown aka yellow */
	0x5555FFFF,	/* light blue */
	0xFF55FFFF,	/* light purple */
	0x55FFFFFF,	/* light cyan */
	0xFFFFFFFF,	/* light grey aka white */
};

/* terminal control */
struct ttystate ttystate[2] = { {0, 1}, {0, 1} };

int	NS;
int	CW;
Consstate *cs;
Mouse	mouse;

int	outfd = -1;
Biobuf	*snarffp = 0;

char	*host_buf;
char	*hostp;			/* input from host */
int	host_bsize = 2*BSIZE;
int	hostlength;			/* amount of input from host */
char	echo_input[BSIZE];
char	*echop = echo_input;	/* characters to echo, after canon */
char	sendbuf[BSIZE];	/* hope you can't type ahead more than BSIZE chars */
char	*sendp = sendbuf;

/* functions */
void	initialize(int, char **);
void	ebegin(int);
int	waitchar(void);
int	rcvchar(void);
void	set_input(char *);
void	set_host(Event *);
void	bigscroll(void);
void	readmenu(void);
void	eresized(int);
void	resize(void);
void	send_interrupt(void);
int	alnum(int);
void	escapedump(int,uchar *,int);
char *term;
struct funckey *fk;

int	debug;
int	logfd = -1;
void
main(int argc, char **argv)
{
	initialize(argc, argv);
	emulate();
}

void
usage(void)
{
	fprint(2, "usage: %s [-2s] [-l logfile]\n", argv0);
	exits("usage");
}

void
initialize(int argc, char **argv)
{
	int i;
	char *fontname, *p;

	rfork(RFNAMEG|RFNOTEG);

	fontname = nil;
	term = "vt100";
	fk = vt100fk;
	ARGBEGIN{
	case 'f':
		fontname = EARGF(usage());
		break;
	case 'a':
		term = "ansi";
		fk = ansifk;
		break;
	case '2':
		term = "vt220";
		fk = vt220fk;
		break;
	case 'x':
		fk = xtermfk;
		term = "xterm";
		break;
	case 'l':
		p = EARGF(usage());
		logfd = create(p, OWRITE, 0666);
		if(logfd < 0)
			sysfatal("could not create log file: %s: %r", p);
		break;
	}ARGEND;

	host_buf = malloc(host_bsize);
	hostp = host_buf;
	hostlength = 0;

	if(initdraw(0, fontname, term) < 0){
		fprint(2, "%s: initdraw failed: %r\n", term);
		exits("initdraw");
	}
	ebegin(Ehost);

	histp = hist;
	menu2.item = menutext2;
	menu3.item = menutext3;
	pagemode = 0;
	blocked = 0;
	NS = font->height;
	CW = stringwidth(font, "m");

	red = allocimage(display, Rect(0,0,1,1), screen->chan, 1, DRed);
	bordercol = allocimage(display, Rect(0,0,1,1), screen->chan, 1, 0xCCCCCCCC);
	cursback = allocimage(display, Rect(0, 0, CW+1, NS+1), screen->chan, 0, DNofill);

	for(i=0; i<8; i++){
		colors[i] = allocimage(display, Rect(0,0,1,1), screen->chan, 1, rgbacolors[i]);
		hicolors[i] = allocimage(display, Rect(0,0,1,1), screen->chan, 1, rgbahicolors[i]);
	}

	bgdefault = display->white;
	fgdefault = display->black;
	bgcolor = bgdefault;
	fgcolor = fgdefault;

	resize();

	if(argc > 0) {
		sendnchars(strlen(argv[0]),argv[0]);
		sendnchars(1,"\n");
	}
}

void
clear(Rectangle r)
{
	draw(screen, r, bgcolor, nil, ZP);
}

void
newline(void)
{
	nbacklines--;
	if(y >= yscrmax) {
		y = yscrmax;
		if(pagemode && olines >= yscrmax) {
			blocked = 1;
			return;
		}
		scroll(yscrmin+1, yscrmax+1, yscrmin, yscrmax);
	} else
		y++;
	olines++;
}

void
cursoff(void)
{
	draw(screen, Rpt(pt(x, y), addpt(pt(x, y), Pt(CW,NS))), 
		cursback, nil, cursback->r.min);
}

void
curson(int bl)
{
	Image *col;

	if(!cursoron){
		cursoff();
		return;
	}

	draw(cursback, cursback->r, screen, nil, pt(x, y));
	if(bl)
		col = red;
	else
		col = bordercol;
	border(screen, Rpt(pt(x, y), addpt(pt(x, y), Pt(CW,NS))), 2, col, ZP);
}

int
get_next_char(void)
{
	int c = peekc;
	uchar buf[1];
	peekc = 0;
	if(c > 0)
		return(c);
	while(c <= 0) {
		if(backp) {
			c = *backp;
			if(c && nbacklines >= 0) {
				backp++;
				if(backp >= &hist[HISTSIZ])
					backp = hist;
				return(c);
			}
			backp = 0;
		}
		c = (uchar)waitchar();
		if(c > 0 && logfd >= 0) {
			buf[0] = c;
			write(logfd, buf, 1);
		}
	}
	*histp++ = c;
	if(histp >= &hist[HISTSIZ])
		histp = hist;
	*histp = '\0';
	return(c);
}

int
canon(char *ep, int c)
{
	if(c&0200)
		return(SCROLL);
	switch(c) {
		case '\b':
			if(sendp > sendbuf)
				sendp--;
			*ep++ = '\b';
			*ep++ = ' ';
			*ep++ = '\b';
			break;
		case 0x15:	/* ^U line kill */
			sendp = sendbuf;
			*ep++ = '^';
			*ep++ = 'U';
			*ep++ = '\n';
			break;
		case 0x17:	/* ^W word kill */
			while(sendp > sendbuf && !alnum(*sendp)) {
				*ep++ = '\b';
				*ep++ = ' ';
				*ep++ = '\b';
				sendp--;
			}
			while(sendp > sendbuf && alnum(*sendp)) {
				*ep++ = '\b';
				*ep++ = ' ';
				*ep++ = '\b';
				sendp--;
			}
			break;
		case '\177':	/* interrupt */
			sendp = sendbuf;
			send_interrupt();
			return(NEWLINE);
		case '\021':	/* quit */
		case '\r':
		case '\n':
			if(sendp < &sendbuf[512])
				*sendp++ = '\n';
			sendnchars((int)(sendp-sendbuf), sendbuf);
			sendp = sendbuf;
			if(c == '\n' || c == '\r') {
				*ep++ = '\n';
			}
			*ep = 0;
			return(NEWLINE);
		case '\004':	/* EOT */
			if(sendp == sendbuf) {
				sendnchars(0,sendbuf);
				*ep = 0;
				return(NEWLINE);
			}
			/* fall through */
		default:
			if(sendp < &sendbuf[512])
				*sendp++ = c;
			*ep++ = c;
			break;
		
	}
	*ep = 0;
	return(OTHER);
}

void
sendfk(char *name)
{
	int i;
	static int fd;

	for(i=0; fk[i].name; i++)
		if(strcmp(name, fk[i].name)==0){
			sendnchars2(strlen(fk[i].sequence), fk[i].sequence);
			return;
		}
}

int
waitchar(void)
{
	Event e;
	int c;
	char c2;
	int newmouse;
	int wasblocked;
	int kbdchar = -1;
	char echobuf[3*BSIZE];
	static int lastc = -1;


	for(;;) {
		if(resize_flag)
			resize();
		wasblocked = blocked;
		if(backp)
			return(0);
		if(ecanmouse() && (button2() || button3()))
			readmenu();
		if(snarffp) {
			if((c = Bgetc(snarffp)) < 0) {
				if(lastc != '\n')
					write(outfd,"\n",1);
				Bterm(snarffp);
				snarffp = 0;
				if(lastc != '\n') {
					lastc = -1;
					return('\n');
				}
				lastc = -1;
				continue;
			}
			lastc = c;
			c2 = c;
			write(outfd, &c2, 1);
			return(c);
		}
		if(!blocked && host_avail())
			return(rcvchar());
		if(kbdchar > 0) {
			if(blocked)
				resize();
			if(cs->raw) {
				switch(kbdchar){
				case Kup:
					sendfk("up key");
					break;
				case Kdown:
					sendfk("down key");
					break;
				case Kleft:
					sendfk("left key");
					break;
				case Kright:
					sendfk("right key");
					break;
				case Kpgup:
					sendfk("page up");
					break;
				case Kpgdown:
					sendfk("page down");
					break;
				case KF|1:
					sendfk("F1");
					break;
				case KF|2:
					sendfk("F2");
					break;
				case KF|3:
					sendfk("F3");
					break;
				case KF|4:
					sendfk("F4");
					break;
				case KF|5:
					sendfk("F5");
					break;
				case KF|6:
					sendfk("F6");
					break;
				case KF|7:
					sendfk("F7");
					break;
				case KF|8:
					sendfk("F8");
					break;
				case KF|9:
					sendfk("F9");
					break;
				case KF|10:
					sendfk("F10");
					break;
				case KF|11:
					sendfk("F11");
					break;
				case KF|12:
					sendfk("F12");
					break;
				case '\n':
					echobuf[0] = '\r';
					sendnchars(1, echobuf);
					break;
				case '\r':
					echobuf[0] = '\n';
					sendnchars(1, echobuf);
					break;
				default:
					echobuf[0] = kbdchar;
					sendnchars(1, echobuf);
					break;
				}
			} else if(canon(echobuf,kbdchar) == SCROLL) {
				if(!blocked)
					bigscroll();
			} else
				strcat(echo_input,echobuf);
			blocked = 0;
			kbdchar = -1;
			continue;
		}
		curson(wasblocked);	/* turn on cursor while we're waiting */
		do {
			newmouse = 0;
			switch(eread(blocked ? Emouse|Ekeyboard : 
					       Emouse|Ekeyboard|Ehost, &e)) {
			case Emouse:
				mouse = e.mouse;
				if(button2() || button3())
					readmenu();
				else if(resize_flag == 0) {
					/* eresized() is triggered by special mouse event */
					newmouse = 1;
				}
				break;
			case Ekeyboard:
				kbdchar = e.kbdc;
				break;
			case Ehost:
				set_host(&e);
				break;
			default:
				perror("protocol violation");
				exits("protocol violation");
			}
		} while(newmouse == 1);
		cursoff();	/* turn cursor back off */
	}
}

void
eresized(int new)
{
	resize_flag = 1+new;
}

void
putenvint(char *name, int x)
{
	char buf[20];

	snprint(buf, sizeof buf, "%d", x);
	putenv(name, buf);
}

void
exportsize(void)
{
	putenvint("XPIXELS", Dx(screen->r)-2*XMARGIN);
	putenvint("YPIXELS", Dy(screen->r)-2*XMARGIN);
	putenvint("LINES", ymax+1);
	putenvint("COLS", xmax+1);
	putenv("TERM", term);
}

void
resize(void)
{
	if(resize_flag > 1 && getwindow(display, Refnone) < 0){
		fprint(2, "can't reattach to window: %r\n");
		exits("can't reattach to window");
	}
	xmax = (Dx(screen->r)-2*XMARGIN)/CW-1;
	ymax = (Dy(screen->r)-2*YMARGIN)/NS-1;
	if(xmax == 0 || ymax == 0)
		exits("window gone");
	x = 0;
	y = 0;
	yscrmin = 0;
	yscrmax = ymax;
	olines = 0;
	exportsize();
	clear(screen->r);
	resize_flag = 0;
}

void
setdim(int ht, int wid)
{
	int fd;
	Rectangle r;

	if(ht != -1)
		ymax = ht-1;
	if(wid != -1)
		xmax = wid-1;

	r.min = screen->r.min;
	r.max = addpt(screen->r.min,
			Pt((xmax+1)*CW+2*XMARGIN+2*INSET,
				(ymax+1)*NS+2*YMARGIN+2*INSET));
	fd = open("/dev/wctl", OWRITE);
	if(fd < 0 || fprint(fd, "resize -dx %d -dy %d\n", Dx(r)+2*Borderwidth, Dy(r)+2*Borderwidth) < 0){
		border(screen, r, INSET, bordercol, ZP);
		exportsize();
	}
	if(fd >= 0)
		close(fd);
}

void
readmenu(void)
{
	if(button3()) {
		menu3.item[1] = ttystate[cs->raw].crnl ? "cr" : "crnl";
		menu3.item[2] = ttystate[cs->raw].nlcr ? "nl" : "nlcr";
		menu3.item[3] = cs->raw ? "cooked" : "raw";

		switch(emenuhit(3, &mouse, &menu3)) {
		case 0:		/* 24x80 */
			setdim(24, 80);
			return;
		case 1:		/* newline after cr? */
			ttystate[cs->raw].crnl = !ttystate[cs->raw].crnl;
			return;
		case 2:		/* cr after newline? */
			ttystate[cs->raw].nlcr = !ttystate[cs->raw].nlcr;
			return;
		case 3:		/* switch raw mode */
			cs->raw = !cs->raw;
			return;
		case 4:
			exits(0);
		}
		return;
	}

	menu2.item[5] = pagemode? "scroll": "page";

	switch(emenuhit(2, &mouse, &menu2)) {

	case 0:		/* back up */
		if(atend == 0) {
			backc++;
			backup(backc);
		}
		return;

	case 1:		/* move forward */
		backc--;
		if(backc >= 0)
			backup(backc);
		else
			backc = 0;
		return;

	case 2:		/* reset */
		backc = 0;
		backup(0);
		return;

	case 3:		/* clear screen */
		eresized(0);
		return;

	case 4:		/* send the snarf buffer */
		snarffp = Bopen("/dev/snarf",OREAD);
		return;

	case 5:		/* pause and clear at end of screen */
		pagemode = 1-pagemode;
		if(blocked && !pagemode) {
			eresized(0);
			blocked = 0;
		}
		return;
	}
}

void
backup(int count)
{
	register n;
	register char *cp;

	eresized(0);
	n = 3*(count+1)*ymax/4;
	cp = histp;
	atend = 0;
	while (n >= 0) {
		cp--;
		if(cp < hist)
			cp = &hist[HISTSIZ-1];
		if(*cp == '\0') {
			atend = 1;
			break;
		}
		if(*cp == '\n')
			n--;
	}
	cp++;
	if(cp >= &hist[HISTSIZ])
		cp = hist;
	backp = cp;
	nbacklines = ymax-2;
}

Point
pt(int x, int y)
{
	return addpt(screen->r.min, Pt(x*CW+XMARGIN,y*NS+YMARGIN));
}

void
scroll(int sy, int ly, int dy, int cy)	/* source, limit, dest, which line to clear */
{
	draw(screen, Rpt(pt(0, dy), pt(xmax+1, dy+ly-sy)), screen, nil, pt(0, sy));
	clear(Rpt(pt(0, cy), pt(xmax+1, cy+1)));
	flushimage(display, 1);
}

void
bigscroll(void)			/* scroll up half a page */
{
	int half = ymax/3;

	if(x == 0 && y == 0)
		return;
	if(y < half) {
		clear(Rpt(pt(0,0),pt(xmax+1,ymax+1)));
		x = y = 0;
		return;
	}
	draw(screen, Rpt(pt(0, 0), pt(xmax+1, ymax+1)), screen, nil, pt(0, half));
	clear(Rpt(pt(0,y-half+1),pt(xmax+1,ymax+1)));
	y -= half;
	if(olines)
		olines -= half;
	flushimage(display, 1);
}

int
number(char *p, int *got)
{
	int c, n = 0;

	if(got)
		*got = 0;
	while ((c = get_next_char()) >= '0' && c <= '9'){
		if(got)
			*got = 1;
		n = n*10 + c - '0';
	}
	*p = c;
	return(n);
}

/* stubs */

void
sendnchars(int n,char *p)
{
	sendnchars2(n, p);
	p[n+1] = 0;
}

void
sendnchars2(int n,char *p)
{
	if(write(outfd,p,n) < 0) {
		close(outfd);
		close(0);
		close(1);
		close(2);
		exits("write");
	}
}

int
host_avail(void)
{
	return(*echop || ((hostp - host_buf) < hostlength));
}

int
rcvchar(void)
{
	int c;
	if(*echop) {
		c = *echop++;
		if(!*echop) {
			echop = echo_input;	
			*echop = 0;
		}
		return c;
	}
	return *hostp++;
}

void
set_host(Event *e)
{
	hostlength = e->n;
	if(hostlength > host_bsize) {
		host_bsize *= 2;
		host_buf = realloc(host_buf,host_bsize);
	}
	hostp = host_buf;
	memmove(host_buf,e->data,hostlength);
	host_buf[hostlength]=0;
}

void
ringbell(void){
}

int
alnum(int c)
{
	if(c >= 'a' && c <= 'z')
		return 1;
	if(c >= 'A' && c <= 'Z')
		return 1;
	if(c >= '0' && c <= '9')
		return 1;
	return 0;
}

void
escapedump(int fd,uchar *str,int len)
{
	int i;

	for(i = 0; i < len; i++) {
		if((str[i] < ' ' || str[i] > '\177') && 
			str[i] != '\n' && str[i] != '\t') fprint(fd,"^%c",str[i]+64);
		else if(str[i] == '\177') fprint(fd,"^$");
		else if(str[i] == '\n') fprint(fd,"^J\n");
		else fprint(fd,"%c",str[i]);
	}
}

void
funckey(int key)
{
	if(key >= NKEYS)
		return;
	if(fk[key].name == 0)
		return;
	sendnchars2(strlen(fk[key].sequence), fk[key].sequence);
}


void
drawstring(Point p, char *str, int attr)
{
	int i;
	Image *txt, *bg, *tmp;
	
	txt = fgcolor;
	bg = bgcolor;
	if(attr & TReverse){
		tmp = txt;
		txt = bg;
		bg = tmp;
	}
	if(attr & THighIntensity){
		for(i=0; i<8; i++)
			if(txt == colors[i])
				txt = hicolors[i];
	}

	draw(screen, Rpt(p, addpt(p, stringsize(font, str))), bg, nil, p);
	string(screen, p, txt, ZP, font, str);
}