xfid.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 <thread.h>
#include <cursor.h>
#include <mouse.h>
#include <keyboard.h>
#include <frame.h>
#include <fcall.h>
#include <plumb.h>
#include "dat.h"
#include "fns.h"

enum
{
	Ctlsize	= 5*12
};

char	Edel[]		= "deleted window";
char	Ebadctl[]		= "ill-formed control message";
char	Ebadaddr[]	= "bad address syntax";
char	Eaddr[]		= "address out of range";
char	Einuse[]		= "already in use";
char	Ebadevent[]	= "bad event syntax";
extern char Eperm[];

static
void
clampaddr(Window *w)
{
	if(w->addr.q0 < 0)
		w->addr.q0 = 0;
	if(w->addr.q1 < 0)
		w->addr.q1 = 0;
	if(w->addr.q0 > w->body.file->nc)
		w->addr.q0 = w->body.file->nc;
	if(w->addr.q1 > w->body.file->nc)
		w->addr.q1 = w->body.file->nc;
}

void
xfidctl(void *arg)
{
	Xfid *x;
	void (*f)(Xfid*);

	threadsetname("xfidctlthread");
	x = arg;
	for(;;){
		f = recvp(x->c);
		(*f)(x);
		flushimage(display, 1);
		sendp(cxfidfree, x);
	}
}

void
xfidflush(Xfid *x)
{
	Fcall fc;
	int i, j;
	Window *w;
	Column *c;
	Xfid *wx;

	/* search windows for matching tag */
	qlock(&row);
	for(j=0; j<row.ncol; j++){
		c = row.col[j];
		for(i=0; i<c->nw; i++){
			w = c->w[i];
			winlock(w, 'E');
			wx = w->eventx;
			if(wx!=nil && wx->tag==x->oldtag){
				w->eventx = nil;
				wx->flushed = TRUE;
				sendp(wx->c, nil);
				winunlock(w);
				goto out;
			}
			winunlock(w);
		}
	}
out:
	qunlock(&row);
	respond(x, &fc, nil);
}

void
xfidopen(Xfid *x)
{
	Fcall fc;
	Window *w;
	Text *t;
	char *s;
	Rune *r;
	int m, n, q, q0, q1;

	w = x->f->w;
	t = &w->body;
	if(w){
		winlock(w, 'E');
		q = FILE(x->f->qid);
		switch(q){
		case QWaddr:
			if(w->nopen[q]++ == 0){
				w->addr = (Range){0,0};
				w->limit = (Range){-1,-1};
			}
			break;
		case QWdata:
		case QWxdata:
			w->nopen[q]++;
			break;
		case QWevent:
			if(w->nopen[q]++ == 0){
				if(!w->isdir && w->col!=nil){
					w->filemenu = FALSE;
					winsettag(w);
				}
			}
			break;
		case QWrdsel:
			/*
			 * Use a temporary file.
			 * A pipe would be the obvious, but we can't afford the
			 * broken pipe notification.  Using the code to read QWbody
			 * is n², which should probably also be fixed.  Even then,
			 * though, we'd need to squirrel away the data in case it's
			 * modified during the operation, e.g. by |sort
			 */
			if(w->rdselfd > 0){
				winunlock(w);
				respond(x, &fc, Einuse);
				return;
			}
			w->rdselfd = tempfile();
			if(w->rdselfd < 0){
				winunlock(w);
				respond(x, &fc, "can't create temp file");
				return;
			}
			w->nopen[q]++;
			q0 = t->q0;
			q1 = t->q1;
			r = fbufalloc();
			s = fbufalloc();
			while(q0 < q1){
				n = q1 - q0;
				if(n > BUFSIZE/UTFmax)
					n = BUFSIZE/UTFmax;
				bufread(t->file, q0, r, n);
				m = snprint(s, BUFSIZE+1, "%.*S", n, r);
				if(write(w->rdselfd, s, m) != m){
					warning(nil, "can't write temp file for pipe command %r\n");
					break;
				}
				q0 += n;
			}
			fbuffree(s);
			fbuffree(r);
			break;
		case QWwrsel:
			w->nopen[q]++;
			seq++;
			filemark(t->file);
			cut(t, t, nil, FALSE, TRUE, nil, 0);
			w->wrselrange = (Range){t->q1, t->q1};
			w->nomark = TRUE;
			break;
		case QWeditout:
			if(editing == FALSE){
				winunlock(w);
				respond(x, &fc, Eperm);
				return;
			}
			w->wrselrange = (Range){t->q1, t->q1};
			break;
		}
		winunlock(w);
	}
	fc.qid = x->f->qid;
	fc.iounit = messagesize-IOHDRSZ;
	x->f->open = TRUE;
	respond(x, &fc, nil);
}

void
xfidclose(Xfid *x)
{
	Fcall fc;
	Window *w;
	int q;
	Text *t;

	w = x->f->w;
	x->f->busy = FALSE;
	if(x->f->open == FALSE){
		if(w != nil)
			winclose(w);
		respond(x, &fc, nil);
		return;
	}

	x->f->open = FALSE;
	if(w){
		winlock(w, 'E');
		q = FILE(x->f->qid);
		switch(q){
		case QWctl:
			if(w->ctlfid!=~0 && w->ctlfid==x->f->fid){
				w->ctlfid = ~0;
				qunlock(&w->ctllock);
			}
			break;
		case QWdata:
		case QWxdata:
			w->nomark = FALSE;
			/* fall through */
		case QWaddr:
		case QWevent:	/* BUG: do we need to shut down Xfid? */
			if(--w->nopen[q] == 0){
				if(q == QWdata || q == QWxdata)
					w->nomark = FALSE;
				if(q==QWevent && !w->isdir && w->col!=nil){
					w->filemenu = TRUE;
					winsettag(w);
				}
				if(q == QWevent){
					free(w->dumpstr);
					free(w->dumpdir);
					w->dumpstr = nil;
					w->dumpdir = nil;
				}
			}
			break;
		case QWrdsel:
			close(w->rdselfd);
			w->rdselfd = 0;
			break;
		case QWwrsel:
			w->nomark = FALSE;
			t = &w->body;
			/* before: only did this if !w->noscroll, but that didn't seem right in practice */
			textshow(t, min(w->wrselrange.q0, t->file->nc),
				min(w->wrselrange.q1, t->file->nc), 1);
			textscrdraw(t);
			break;
		}
		winunlock(w);
		winclose(w);
	}
	respond(x, &fc, nil);
}

void
xfidread(Xfid *x)
{
	Fcall fc;
	int n, q;
	uint off;
	char *b;
	char buf[128];
	Window *w;

	q = FILE(x->f->qid);
	w = x->f->w;
	if(w == nil){
		fc.count = 0;
		switch(q){
		case Qcons:
		case Qlabel:
			break;
		case Qindex:
			xfidindexread(x);
			return;
		default:
			warning(nil, "unknown qid %d\n", q);
			break;
		}
		respond(x, &fc, nil);
		return;
	}
	winlock(w, 'F');
	if(w->col == nil){
		winunlock(w);
		respond(x, &fc, Edel);
		return;
	}
	off = x->offset;
	switch(q){
	case QWaddr:
		textcommit(&w->body, TRUE);
		clampaddr(w);
		sprint(buf, "%11d %11d ", w->addr.q0, w->addr.q1);
		goto Readbuf;

	case QWbody:
		xfidutfread(x, &w->body, w->body.file->nc, QWbody);
		break;

	case QWctl:
		b = winctlprint(w, buf, 1);
		goto Readb;

	Readbuf:
		b = buf;
	Readb:
		n = strlen(b);
		if(off > n)
			off = n;
		if(off+x->count > n)
			x->count = n-off;
		fc.count = x->count;
		fc.data = b+off;
		respond(x, &fc, nil);
		if(b != buf)
			free(b);
		break;

	case QWevent:
		xfideventread(x, w);
		break;

	case QWdata:
		/* BUG: what should happen if q1 > q0? */
		if(w->addr.q0 > w->body.file->nc){
			respond(x, &fc, Eaddr);
			break;
		}
		w->addr.q0 += xfidruneread(x, &w->body, w->addr.q0, w->body.file->nc);
		w->addr.q1 = w->addr.q0;
		break;

	case QWxdata:
		/* BUG: what should happen if q1 > q0? */
		if(w->addr.q0 > w->body.file->nc){
			respond(x, &fc, Eaddr);
			break;
		}
		w->addr.q0 += xfidruneread(x, &w->body, w->addr.q0, w->addr.q1);
		break;

	case QWtag:
		xfidutfread(x, &w->tag, w->tag.file->nc, QWtag);
		break;

	case QWrdsel:
		seek(w->rdselfd, off, 0);
		n = x->count;
		if(n > BUFSIZE)
			n = BUFSIZE;
		b = fbufalloc();
		n = read(w->rdselfd, b, n);
		if(n < 0){
			respond(x, &fc, "I/O error in temp file");
			break;
		}
		fc.count = n;
		fc.data = b;
		respond(x, &fc, nil);
		fbuffree(b);
		break;

	default:
		sprint(buf, "unknown qid %d in read", q);
		respond(x, &fc, nil);
	}
	winunlock(w);
}

void
xfidwrite(Xfid *x)
{
	Fcall fc;
	int c, cnt, qid, q, nb, nr, eval;
	char buf[64], *err;
	Window *w;
	Rune *r;
	Range a;
	Text *t;
	uint q0, tq0, tq1;

	qid = FILE(x->f->qid);
	w = x->f->w;
	if(w){
		c = 'F';
		if(qid==QWtag || qid==QWbody)
			c = 'E';
		winlock(w, c);
		if(w->col == nil){
			winunlock(w);
			respond(x, &fc, Edel);
			return;
		}
	}
	x->data[x->count] = 0;
	switch(qid){
	case Qcons:
		w = errorwin(x->f->mntdir, 'X');
		t=&w->body;
		goto BodyTag;

	case Qlabel:
		fc.count = x->count;
		respond(x, &fc, nil);
		break;

	case QWaddr:
		x->data[x->count] = 0;
		r = bytetorune(x->data, &nr);
		t = &w->body;
		wincommit(w, t);
		eval = TRUE;
		a = address(x->f->mntdir, t, w->limit, w->addr, r, 0, nr, rgetc, &eval, (uint*)&nb);
		free(r);
		if(nb < nr){
			respond(x, &fc, Ebadaddr);
			break;
		}
		if(!eval){
			respond(x, &fc, Eaddr);
			break;
		}
		w->addr = a;
		fc.count = x->count;
		respond(x, &fc, nil);
		break;

	case Qeditout:
	case QWeditout:
		r = bytetorune(x->data, &nr);
		if(w)
			err = edittext(w, w->wrselrange.q1, r, nr);
		else
			err = edittext(nil, 0, r, nr);
		free(r);
		if(err != nil){
			respond(x, &fc, err);
			break;
		}
		fc.count = x->count;
		respond(x, &fc, nil);
		break;

	case QWerrors:
		w = errorwinforwin(w);
		t = &w->body;
		goto BodyTag;

	case QWbody:
	case QWwrsel:
		t = &w->body;
		goto BodyTag;

	case QWctl:
		xfidctlwrite(x, w);
		break;

	case QWdata:
		a = w->addr;
		t = &w->body;
		wincommit(w, t);
		if(a.q0>t->file->nc || a.q1>t->file->nc){
			respond(x, &fc, Eaddr);
			break;
		}
		r = runemalloc(x->count);
		cvttorunes(x->data, x->count, r, &nb, &nr, nil);
		if(w->nomark == FALSE){
			seq++;
			filemark(t->file);
		}
		q0 = a.q0;
		if(a.q1 > q0){
			textdelete(t, q0, a.q1, TRUE);
			w->addr.q1 = q0;
		}
		tq0 = t->q0;
		tq1 = t->q1;
		textinsert(t, q0, r, nr, TRUE);
		if(tq0 >= q0)
			tq0 += nr;
		if(tq1 >= q0)
			tq1 += nr;
		textsetselect(t, tq0, tq1);
		if(!t->w->noscroll)
			textshow(t, q0, q0+nr, 0);
		textscrdraw(t);
		winsettag(w);
		free(r);
		w->addr.q0 += nr;
		w->addr.q1 = w->addr.q0;
		fc.count = x->count;
		respond(x, &fc, nil);
		break;

	case QWevent:
		xfideventwrite(x, w);
		break;

	case QWtag:
		t = &w->tag;
		goto BodyTag;

	BodyTag:
		q = x->f->nrpart;
		cnt = x->count;
		if(q > 0){
			memmove(x->data+q, x->data, cnt);	/* there's room; see fsysproc */
			memmove(x->data, x->f->rpart, q);
			cnt += q;
			x->f->nrpart = 0;
		}
		r = runemalloc(cnt);
		cvttorunes(x->data, cnt-UTFmax, r, &nb, &nr, nil);
		/* approach end of buffer */
		while(fullrune(x->data+nb, cnt-nb)){
			c = nb;
			nb += chartorune(&r[nr], x->data+c);
			if(r[nr])
				nr++;
		}
		if(nb < cnt){
			memmove(x->f->rpart, x->data+nb, cnt-nb);
			x->f->nrpart = cnt-nb;
		}
		if(nr > 0){
			wincommit(w, t);
			if(qid == QWwrsel){
				q0 = w->wrselrange.q1;
				if(q0 > t->file->nc)
					q0 = t->file->nc;
			}else
				q0 = t->file->nc;
			if(qid == QWtag)
				textinsert(t, q0, r, nr, TRUE);
			else{