shithub: patch

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page-del: allow popping/removing subentries, required for dirs

+ misc checks and sanitization

--- a/page-del

+++ b/page-del

@@ -1,4 +1,4 @@

-diff c4e30bede2f79c42dacb8c91713abf4a4d91c45c uncommitted

+diff aa14ba62fd02ffd0e7053c23b2918e7aa46bcb86 uncommitted

 --- a//sys/src/cmd/page.c

 +++ b//sys/src/cmd/page.c

 @@ -74,7 +74,10 @@

@@ -35,96 +35,102 @@

  	}

  }

-+/* page entries are never freed, there's no point

-+ * and would break everything */

++/* doesn't actually free the page entry or touch links to avoid breakage */

 +Page*

-+poppage(Page *p)

++freepage(Page *p, Page *prev)

 +{

-+	Page *t, *q;

++	Page *next, *up;

 +

-+	if(p == nil)

-+		return nil;

-+	if(p->up != root)

-+		return p;

-+	qlock(&pagelock);

-+	for(t = p->down; t != nil && t->up != root; t = q){

-+		qlock(t);

-+		drawlock(0);

-+		unloadpage(t);

-+		drawlock(1);

-+		free(t->name);

-+		free(t->data);

-+		t->name = t->data = nil;

-+		q = nextpage(t);

-+		qunlock(t);

-+	}

 +	drawlock(0);

 +	unloadpage(p);

 +	drawlock(1);

++	if(p->fd >= 0)

++		close(p->fd);

++	p->fd = -1;

 +	free(p->name);

 +	free(p->data);

-+	p->name = p->data = nil;

-+	t = prevpage(p);

-+	if(root->tail == p)

-+		root->tail = t;

-+	if(root->down == p || t == nil)

-+		root->down = p->next;

-+	else

-+		t->next = p->next;

-+	qunlock(&pagelock);

-+	qunlock(p);

-+	if(p->next != nil){

-+		forward = 1;

-+		return p->next;

-+	}

-+	forward = -1;

-+	return t;

++	p->name = p->data = p->open = nil;

++	next = nextpage(p);

++	up = p->up;

++	if(up->down == p){

++		if(up->tail != p)

++			up->down = next;

++		else

++			up->down = nil;

++	}else if(up->tail == p){

++		up->tail = prev;

++		prev->next = nil;

++	}else

++		prev->next = next;

++	return next;

 +}

 +

 +Page*

-+delpage(Page *p)

++poppage(Page *p, int del)

 +{

++	Page *t, *prev, *next;

++

 +	if(p == nil)

 +		return nil;

-+	/* to remove(2) subpages in documents makes no sense, and just

-+	 * removing a subentry doesn't seem like a feature worth the bother */

-+	if(p->up != root)

++	if(p == root)

 +		return p;

-+	if(p->fd >= 0)

-+		close(p->fd);

-+	p->fd = -1;

-+	if(remove(p->name) < 0){

-+		fprint(2, "remove %s: %r", p->name);

-+		return p;

++	if(del){

++		if(!(access(p->name, OREAD) == 0 && remove(p->name) == 0

++		|| p->data != nil && access(p->data, OREAD) == 0 && remove(p->data) == 0)){

++			fprint(2, "remove %s: %r", p->name);

++			return p;

++		}

 +	}

-+	return poppage(p);

++	qlock(&pagelock);

++	for(t = p->down, prev = p; t != nil && t->up != p->up; prev = t, t = next){

++		qlock(t);

++		next = freepage(t, prev);

++		qunlock(t);

++	}

++	p->down = nil;

++	prev = prevpage(p);

++	next = freepage(p, prev);

++	qunlock(&pagelock);

++	qunlock(p);

++	if(next != nil){

++		forward = 1;

++		return next;

++	}

++	forward = -1;

++	return prev;

 +}

 +

  /*

   * A draw operation that touches only the area contained in bot but not in top.

   * mp and sp get aligned with bot.min.

-@@ -1461,6 +1533,7 @@

+@@ -1460,8 +1532,10 @@

+ {

  	char buf[NPATH], *s;

  	Point o;

- 	int fd;

+-	int fd;

++	int fd, del;

 +	Page *p;

++	del = 0;

  	switch(i){

  	case Corigsize:

-@@ -1546,6 +1619,32 @@

+ 		pos = ZP;

+@@ -1545,6 +1619,25 @@

+ 		break;

  	case Csnarf:

  		writeaddr(current, "/dev/snarf");

- 		break;

++		break;

++	case Cdelete:

++		del = 1;

++		/* wet floor */

 +	case Cpop:

 +		if(current == nil || !canqlock(current))

 +			break;

-+		if((p = poppage(current)) == current){

++		if((p = poppage(current, del)) == current){

 +			qunlock(current);

 +			break;

 +		}

-+	Reset:

-+		current = p;

-+		if(current == nil){

++		if((current = p) == nil){

 +			drawlock(0);

 +			draw(screen, screen->r, paper, nil, ZP);

 +			drawframe(screen->r);

@@ -132,15 +138,6 @@

 +			break;

 +		}

 +		showpage(current);

-+		break;

-+	case Cdelete:

-+		if(current == nil || !canqlock(current))

-+			break;

-+		if((p = delpage(current)) == current){

-+			qunlock(current);

-+			break;

-+		}

-+		goto Reset;

+ 		break;

  	case Cnext:

  		forward = 1;

- 		showpage(nextpage(current));