exec.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"

Buffer	snarfbuf;

void	del(Text*, Text*, Text*, int, int, Rune*, int);
void	delcol(Text*, Text*, Text*, int, int, Rune*, int);
void	dump(Text*, Text*, Text*, int, int, Rune*, int);
void	edit(Text*, Text*, Text*, int, int, Rune*, int);
void	exit(Text*, Text*, Text*, int, int, Rune*, int);
void	fontx(Text*, Text*, Text*, int, int, Rune*, int);
void	get(Text*, Text*, Text*, int, int, Rune*, int);
void	id(Text*, Text*, Text*, int, int, Rune*, int);
void	incl(Text*, Text*, Text*, int, int, Rune*, int);
void	indent(Text*, Text*, Text*, int, int, Rune*, int);
void	kill(Text*, Text*, Text*, int, int, Rune*, int);
void	local(Text*, Text*, Text*, int, int, Rune*, int);
void	look(Text*, Text*, Text*, int, int, Rune*, int);
void	newcol(Text*, Text*, Text*, int, int, Rune*, int);
void	paste(Text*, Text*, Text*, int, int, Rune*, int);
void	put(Text*, Text*, Text*, int, int, Rune*, int);
void	putall(Text*, Text*, Text*, int, int, Rune*, int);
void	sendx(Text*, Text*, Text*, int, int, Rune*, int);
void	sort(Text*, Text*, Text*, int, int, Rune*, int);
void	tab(Text*, Text*, Text*, int, int, Rune*, int);
void	zeroxx(Text*, Text*, Text*, int, int, Rune*, int);

typedef struct Exectab Exectab;
struct Exectab
{
	Rune	*name;
	void	(*fn)(Text*, Text*, Text*, int, int, Rune*, int);
	int		mark;
	int		flag1;
	int		flag2;
};

Exectab exectab[] = {
	{ L"Cut",		cut,		TRUE,	TRUE,	TRUE	},
	{ L"Del",		del,		FALSE,	FALSE,	XXX		},
	{ L"Delcol",	delcol,	FALSE,	XXX,		XXX		},
	{ L"Delete",	del,		FALSE,	TRUE,	XXX		},
	{ L"Dump",	dump,	FALSE,	TRUE,	XXX		},
	{ L"Edit",		edit,		FALSE,	XXX,		XXX		},
	{ L"Exit",		exit,		FALSE,	XXX,		XXX		},
	{ L"Font",		fontx,	FALSE,	XXX,		XXX		},
	{ L"Get",		get,		FALSE,	TRUE,	XXX		},
	{ L"ID",		id,		FALSE,	XXX,		XXX		},
	{ L"Incl",		incl,		FALSE,	XXX,		XXX		},
	{ L"Indent",	indent,	FALSE,	XXX,		XXX		},
	{ L"Kill",		kill,		FALSE,	XXX,		XXX		},
	{ L"Load",		dump,	FALSE,	FALSE,	XXX		},
	{ L"Local",		local,	FALSE,	XXX,		XXX		},
	{ L"Look",		look,		FALSE,	XXX,		XXX		},
	{ L"New",		new,		FALSE,	XXX,		XXX		},
	{ L"Newcol",	newcol,	FALSE,	XXX,		XXX		},
	{ L"Paste",		paste,	TRUE,	TRUE,	XXX		},
	{ L"Put",		put,		FALSE,	XXX,		XXX		},
	{ L"Putall",		putall,	FALSE,	XXX,		XXX		},
	{ L"Redo",		undo,	FALSE,	FALSE,	XXX		},
	{ L"Send",		sendx,	TRUE,	XXX,		XXX		},
	{ L"Snarf",		cut,		FALSE,	TRUE,	FALSE	},
	{ L"Sort",		sort,		FALSE,	XXX,		XXX		},
	{ L"Tab",		tab,		FALSE,	XXX,		XXX		},
	{ L"Undo",		undo,	FALSE,	TRUE,	XXX		},
	{ L"Zerox",	zeroxx,	FALSE,	XXX,		XXX		},
	{ nil, 			nil,		0,		0,		0		},
};

Exectab*
lookup(Rune *r, int n)
{
	Exectab *e;
	int nr;

	r = skipbl(r, n, &n);
	if(n == 0)
		return nil;
	findbl(r, n, &nr);
	nr = n-nr;
	for(e=exectab; e->name; e++)
		if(runeeq(r, nr, e->name, runestrlen(e->name)) == TRUE)
			return e;
	return nil;
}

int
isexecc(int c)
{
	if(isfilec(c))
		return 1;
	return c=='<' || c=='|' || c=='>';
}

void
execute(Text *t, uint aq0, uint aq1, int external, Text *argt)
{
	uint q0, q1;
	Rune *r, *s;
	char *b, *a, *aa;
	Exectab *e;
	int c, n, f;
	Runestr dir;

	q0 = aq0;
	q1 = aq1;
	if(q1 == q0){	/* expand to find word (actually file name) */
		/* if in selection, choose selection */
		if(t->q1>t->q0 && t->q0<=q0 && q0<=t->q1){
			q0 = t->q0;
			q1 = t->q1;
		}else{
			while(q1<t->file->nc && isexecc(c=textreadc(t, q1)) && c!=':')
				q1++;
			while(q0>0 && isexecc(c=textreadc(t, q0-1)) && c!=':')
				q0--;
			if(q1 == q0)
				return;
		}
	}
	r = runemalloc(q1-q0);
	bufread(t->file, q0, r, q1-q0);
	e = lookup(r, q1-q0);
	if(!external && t->w!=nil && t->w->nopen[QWevent]>0){
		f = 0;
		if(e)
			f |= 1;
		if(q0!=aq0 || q1!=aq1){
			bufread(t->file, aq0, r, aq1-aq0);
			f |= 2;
		}
		aa = getbytearg(argt, TRUE, TRUE, &a);
		if(a){	
			if(strlen(a) > EVENTSIZE){	/* too big; too bad */
				free(aa);
				free(a);
				warning(nil, "`argument string too long\n");
				return;
			}
			f |= 8;
		}
		c = 'x';
		if(t->what == Body)
			c = 'X';
		n = aq1-aq0;
		if(n <= EVENTSIZE)
			winevent(t->w, "%c%d %d %d %d %.*S\n", c, aq0, aq1, f, n, n, r);
		else
			winevent(t->w, "%c%d %d %d 0 \n", c, aq0, aq1, f, n);
		if(q0!=aq0 || q1!=aq1){
			n = q1-q0;
			bufread(t->file, q0, r, n);
			if(n <= EVENTSIZE)
				winevent(t->w, "%c%d %d 0 %d %.*S\n", c, q0, q1, n, n, r);
			else
				winevent(t->w, "%c%d %d 0 0 \n", c, q0, q1, n);
		}
		if(a){
			winevent(t->w, "%c0 0 0 %d %s\n", c, utflen(a), a);
			if(aa)
				winevent(t->w, "%c0 0 0 %d %s\n", c, utflen(aa), aa);
			else
				winevent(t->w, "%c0 0 0 0 \n", c);
		}
		free(r);
		free(aa);
		free(a);
		return;
	}
	if(e){
		if(e->mark && seltext!=nil)
		if(seltext->what == Body){
			seq++;
			filemark(seltext->w->body.file);
		}
		s = skipbl(r, q1-q0, &n);
		s = findbl(s, n, &n);
		s = skipbl(s, n, &n);
		(*e->fn)(t, seltext, argt, e->flag1, e->flag2, s, n);
		free(r);
		return;
	}

	b = runetobyte(r, q1-q0);
	free(r);
	dir = dirname(t, nil, 0);
	if(dir.nr==1 && dir.r[0]=='.'){	/* sigh */
		free(dir.r);
		dir.r = nil;
		dir.nr = 0;
	}
	aa = getbytearg(argt, TRUE, TRUE, &a);
	if(t->w)
		incref(t->w);
	run(t->w, b, dir.r, dir.nr, TRUE, aa, a, FALSE);
}

char*
printarg(Text *argt, uint q0, uint q1)
{
	char *buf;

	if(argt->what!=Body || argt->file->name==nil)
		return nil;
	buf = emalloc(argt->file->nname+32);
	if(q0 == q1)
		sprint(buf, "%.*S:#%d", argt->file->nname, argt->file->name, q0);
	else
		sprint(buf, "%.*S:#%d,#%d", argt->file->nname, argt->file->name, q0, q1);
	return buf;
}

char*
getarg(Text *argt, int doaddr, int dofile, Rune **rp, int *nrp)
{
	int n;
	Expand e;
	char *a;

	*rp = nil;
	*nrp = 0;
	if(argt == nil)
		return nil;
	a = nil;
	textcommit(argt, TRUE);
	if(expand(argt, argt->q0, argt->q1, &e)){
		free(e.bname);
		if(e.nname && dofile){
			e.name = runerealloc(e.name, e.nname+1);
			if(doaddr)
				a = printarg(argt, e.q0, e.q1);
			*rp = e.name;
			*nrp = e.nname;
			return a;
		}
		free(e.name);
	}else{
		e.q0 = argt->q0;
		e.q1 = argt->q1;
	}
	n = e.q1 - e.q0;
	*rp = runemalloc(n+1);
	bufread(argt->file, e.q0, *rp, n);
	if(doaddr)
		a = printarg(argt, e.q0, e.q1);
	*nrp = n;
	return a;
}

char*
getbytearg(Text *argt, int doaddr, int dofile, char **bp)
{
	Rune *r;
	int n;
	char *aa;

	*bp = nil;
	aa = getarg(argt, doaddr, dofile, &r, &n);
	if(r == nil)
		return nil;
	*bp = runetobyte(r, n);
	free(r);
	return aa;
}

void
newcol(Text *et, Text*, Text*, int, int, Rune*, int)
{
	Column *c;

	c = rowadd(et->row, nil, -1);
	if(c)
		winsettag(coladd(c, nil, nil, -1));
}

void
delcol(Text *et, Text*, Text*, int, int, Rune*, int)
{
	int i;
	Column *c;
	Window *w;

	c = et->col;
	if(c==nil || colclean(c)==0)
		return;
	for(i=0; i<c->nw; i++){
		w = c->w[i];
		if(w->nopen[QWevent]+w->nopen[QWaddr]+w->nopen[QWdata]+w->nopen[QWxdata] > 0){
			warning(nil, "can't delete column; %.*S is running an external command\n", w->body.file->nname, w->body.file->name);
			return;
		}
	}
	rowclose(et->col->row, et->col, TRUE);
}

void
del(Text *et, Text*, Text*, int flag1, int, Rune*, int)
{
	if(et->col==nil || et->w == nil)
		return;
	if(flag1 || et->w->body.file->ntext>1 || winclean(et->w, FALSE))
		colclose(et->col, et->w, TRUE);
}

void
sort(Text *et, Text*, Text*, int, int, Rune*, int)
{
	if(et->col)
		colsort(et->col);
}

uint
seqof(Window *w, int isundo)
{
	/* if it's undo, see who changed with us */
	if(isundo)
		return w->body.file->seq;
	/* if it's redo, see who we'll be sync'ed up with */
	return fileredoseq(w->body.file);
}

void
undo(Text *et, Text*, Text*, int flag1, int, Rune*, int)
{
	int i, j;
	Column *c;
	Window *w;
	uint seq;

	if(et==nil || et->w== nil)
		return;
	seq = seqof(et->w, flag1);
	if(seq == 0){
		/* nothing to undo */
		return;
	}
	/*
	 * Undo the executing window first. Its display will update. other windows
	 * in the same file will not call show() and jump to a different location in the file.
	 * Simultaneous changes to other files will be chaotic, however.
	 */
	winundo(et->w, flag1);
	for(i=0; i<row.ncol; i++){
		c = row.col[i];
		for(j=0; j<c->nw; j++){
			w = c->w[j];
			if(w == et->w)
				continue;
			if(seqof(w, flag1) == seq)
				winundo(w, flag1);
		}
	}
}

char*
getname(Text *t, Text *argt, Rune *arg, int narg, int isput)
{
	char *s;
	Rune *r;
	int i, n, promote;
	Runestr dir;

	getarg(argt, FALSE, TRUE, &r, &n);
	promote = FALSE;
	if(r == nil)
		promote = TRUE;
	else if(isput){
		/* if are doing a Put, want to synthesize name even for non-existent file */
		/* best guess is that file name doesn't contain a slash */
		promote = TRUE;
		for(i=0; i<n; i++)
			if(r[i] == '/'){
				promote = FALSE;
				break;
			}
		if(promote){
			t = argt;
			arg = r;
			narg = n;
		}
	}
	if(promote){
		n = narg;
		if(n <= 0){
			s = runetobyte(t->file->name, t->file->nname);
			return s;
		}
		/* prefix with directory name if necessary */
		dir.r = nil;
		dir.nr = 0;
		if(n>0 && arg[0]!='/'){
			dir = dirname(t, nil, 0);
			if(dir.nr==1 && dir.r[0]=='.'){	/* sigh */
				free(dir.r);
				dir.r = nil;
				dir.nr = 0;
			}
		}
		if(dir.r){
			r = runemalloc(dir.nr+n+1);
			runemove(r, dir.r, dir.nr);
			free(dir.r);
			if(dir.nr>0 && r[dir.nr]!='/' && n>0 && arg[0]!='/')
				r[dir.nr++] = '/';
			runemove(r+dir.nr, arg, n);
			n += dir.nr;
		}else{
			r = runemalloc(n+1);
			runemove(r, arg, n);
		}
	}
	s = runetobyte(r, n);
	free(r);
	if(strlen(s) == 0){
		free(s);
		s = nil;
	}
	return s;
}

void
zeroxx(Text *et, Text *t, Text*, int, int, Rune*, int)
{
	Window *nw;
	int c, locked;

	locked = FALSE;
	if(t!=nil && t->w!=nil && t->w!=et->w){
		locked = TRUE;
		c = 'M';
		if(et->w)
			c = et->w->owner;
		winlock(t->w, c);
	}
	if(t == nil)
		t = et;
	if(t==nil || t->w==nil)
		return;
	t = &t->w->body;
	if(t->w->isdir)
		warning(nil, "%.*S is a directory; Zerox illegal\n", t->file->nname, t->file->name);
	else{
		nw = coladd(t->w->col, nil, t->w, -1);
		/* ugly: fix locks so w->unlock works */
		winlock1(nw, t->w->owner);
	}
	if(locked)
		winunlock(t->w);
}

void
get(Text *et, Text *t, Text *argt, int flag1, int, Rune *arg, int narg)
{
	char *name;
	Rune *r;
	int i, n, dirty, samename, isdir;
	Window *w;
	Text *u;
	Dir *d;

	if(flag1)
		if(et==nil || et->w==nil)
			return;
	if(!et->w->isdir && (et->w->body.file->nc>0 && !winclean(et->w, TRUE)))
		return;
	w = et->w;
	t = &w->body;
	name = getname(t, argt, arg, narg, FALSE);
	if(name == nil){
		warning(nil, "no file name\n");
		return;
	}
	if(t->file->ntext>1){
		d = dirstat(name);
		isdir = (d!=nil && (d->qid.type & QTDIR));
		free(d);
		if(isdir){
			warning(nil, "%s is a directory; can't read with multiple windows on it\n", name);
			return;
		}
	}
	r = bytetorune(name, &n);
	for(i=0; i<t->file->ntext; i++){
		u = t->file->text[i];
		/* second and subsequent calls with zero an already empty buffer, but OK */
		textreset(u);
		windirfree(u->w);
	}
	samename = runeeq(r, n, t->file->name, t->file->nname);
	textload(t, 0, name, samename);
	if(samename){
		t->file->mod = FALSE;
		dirty = FALSE;
	}else{
		t->file->mod = TRUE;
		dirty = TRUE;
	}
	for(i=0; i<t->file->ntext; i++)
		t->file->text[i]->w->dirty = dirty;
	free(name);
	free(r);
	winsettag(w);
	t->file->unread = FALSE;
	for(i=0; i<t->file->ntext; i++){
		u = t->file->text[i];
		textsetselect(&u->w->tag, u->w->tag.file->nc, u->w->tag.file->nc);
		textscrdraw(u);
	}
}

void
putfile(File *f, int q0, int q1, Rune *namer, int nname)
{
	uint n, m;
	Rune *r;
	char *s, *name;
	int i, fd, q;
	Dir *d, *d1;
	Window *w;
	int isapp;

	w = f->curtext->w;
	name = runetobyte(namer, nname);
	d = dirstat(name);
	if(d!=nil && runeeq(namer, nname, f->name, f->nname)){
		/* f->mtime+1 because when talking over NFS it's often off by a second */
		if(f->dev!=d->dev || f->qidpath!=d->qid.path || f->mtime+1<d->mtime){
			f->dev = d->dev;
			f->qidpath = d->qid.path;
			f->mtime = d->mtime;
			if(f->unread)
				warning(nil, "%s not written; file already exists\n", name);
			else
				warning(nil, "%s modified%s%s since last read\n", name, d->muid[0]?" by ":"", d->muid);
			goto Rescue1;
		}
	}
	fd = create(name, OWRITE, 0666);
	if(fd < 0){
		warning(nil, "can't create file %s: %r\n", name);
		goto Rescue1;
	}
	r = fbufalloc();
	s = fbufalloc();
	free(d);
	d = dirfstat(fd);
	isapp = (d!=nil && d->length>0 && (d->qid.type&QTAPPEND));
	if(isapp){
		warning(nil, "%s not written; file is append only\n", name);
		goto Rescue2;
	}

	for(q=q0; q<q1; q+=n){
		n = q1 - q;
		if(n > BUFSIZE/UTFmax)
			n = BUFSIZE/UTFmax;
		bufread(f, q, r, n);
		m = snprint(s, BUFSIZE+1, "%.*S", n, r);
		if(write(fd, s, m) != m){
			warning(nil, "can't write file %s: %r\n", name);
			goto Rescue2;
		}
	}
	if(runeeq(namer, nname, f->name, f->nname)){
		if(q0!=0 || q1!=f->nc){
			f->mod = TRUE;
			w->dirty = TRUE;
			f->unread = TRUE;
		}else{
			d1 = dirfstat(fd);
			if(d1 != nil){
				free(d);
				d = d1;
			}
			f->qidpath = d->qid.path;
			f->dev = d->dev;
			f->mtime = d->mtime;
			f->mod = FALSE;
			w->dirty = FALSE;
			f->unread = FALSE;
		}
		for(i=0; i<f->ntext; i++){
			f->text[i]->w->putseq = f->seq;
			f->text[i]->w->dirty = w->dirty;
		}
	}
	fbuffree(s);
	fbuffree(r);
	free(d);
	free(namer);
	free(name);
	close(fd);
	winsettag(w);
	return;

    Rescue2:
	fbuffree(s);
	fbuffree(r);
	close(fd);
	/* fall through */

    Rescue1:
	free(d);
	free(namer);
	free(name);
}

void
put(Text *et, Text*, Text *argt, int, int, Rune *arg, int narg)
{
	int nname;
	Rune  *namer;
	Window *w;
	File *f;
	char *name;

	if(et==nil || et->w==nil || et->w->isdir)
		return;
	w = et->w;
	f = w->body.file;
	name = getname(&w->body, argt, arg, narg, TRUE);
	if(name == nil){
		warning(nil, "no file name\n");
		return;
	}
	namer = bytetorune(name, &nname);
	putfile(f, 0, f->nc, namer, nname);
	free(name);
}

void
dump(Text *, Text *, Text *argt, int isdump, int, Rune *arg, int narg)
{
	char *name;

	if(narg)
		name = runetobyte(arg, narg);
	else
		getbytearg(argt, FALSE, TRUE, &name);
	if(isdump)
		rowdump(&row, name);
	else
		rowload(&row, name, FALSE);
	free(name);
}

void
cut(Text *et, Text *t, Text*, int dosnarf, int docut, Rune*, int)
{
	uint q0, q1, n, locked, c;
	Rune *r;

	/* use current window if snarfing and its selection is non-null */
	if(et!=nil && dosnarf && et->w!=nil && t==nil){
		if(et->w->body.q1>et->w->body.q0){
			t = &et->w->body;
			if(docut)
				filemark(t->file);	/* seq has been incremented by execute */
		}else if(et->w->tag.q1>et->w->tag.q0)
			t = &et->w->tag;
	}
	if(t == nil){
		/* can only happen if seltext == nil */
		return;
	}
	locked = FALSE;
	if(t->w!=nil && et->w!=t->w){
		locked = TRUE;
		c = 'M';
		if(et->w)
			c = et->w->owner;
		winlock(t->w, c);
	}
	if(t->q0 == t->q1){
		if(locked)
			winunlock(t->w);
		return;
	}
	if(dosnarf){
		q0 = t->q0;
		q1 = t->q1;
		bufdelete(&snarfbuf, 0, snarfbuf.nc);
		r = fbufalloc();
		while(q0 < q1){
			n = q1 - q0;
			if(n > RBUFSIZE)
				n = RBUFSIZE;