shithub: patch

ref: 246e05a5735206e309d4f3ce221c6460e5562878
dir: /page-del/

diff c4e30bede2f79c42dacb8c91713abf4a4d91c45c uncommitted
--- a//sys/src/cmd/page.c
+++ b//sys/src/cmd/page.c
@@ -74,7 +74,10 @@
 	Czerox,
 	Cwrite,
 	Cext,
+	Cpop,
 	Cdummy2,
+	Cdelete,
+	Cdummy3,
 	Cquit,
 };
 
@@ -98,7 +101,10 @@
 	[Czerox]	"zerox",	'z', 0, 0,
 	[Cwrite]	"write",	'w', 0, 0,
 	[Cext]		"ext",		'x', 0, 0,
+	[Cpop]		"pop",		'p', 0, 0,
 	[Cdummy2]	"",		0, 0, 0,
+	[Cdelete]	"delete",	'D', 0, 0,
+	[Cdummy3]	"",		0, 0, 0,
 	[Cquit]		"quit",		'q', Kdel, Keof,
 };
 
@@ -134,6 +140,7 @@
 void showpage(Page *);
 void drawpage(Page *);
 Point pagesize(Page *);
+void drawlock(int);
 
 Page*
 addpage(Page *up, char *name, int (*popen)(Page *), void *pdata, int fd)
@@ -986,6 +993,71 @@
 	}
 }
 
+/* page entries are never freed, there's no point
+ * and would break everything */
+Page*
+poppage(Page *p)
+{
+	Page *t, *q;
+
+	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);
+	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;
+}
+
+Page*
+delpage(Page *p)
+{
+	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)
+		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;
+	}
+	return poppage(p);
+}
+
 /*
  * 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 @@
 	char buf[NPATH], *s;
 	Point o;
 	int fd;
+	Page *p;
 
 	switch(i){
 	case Corigsize:
@@ -1546,6 +1619,32 @@
 	case Csnarf:
 		writeaddr(current, "/dev/snarf");
 		break;
+	case Cpop:
+		if(current == nil || !canqlock(current))
+			break;
+		if((p = poppage(current)) == current){
+			qunlock(current);
+			break;
+		}
+	Reset:
+		current = p;
+		if(current == nil){
+			drawlock(0);
+			draw(screen, screen->r, paper, nil, ZP);
+			drawframe(screen->r);
+			drawlock(1);
+			break;
+		}
+		showpage(current);
+		break;
+	case Cdelete:
+		if(current == nil || !canqlock(current))
+			break;
+		if((p = delpage(current)) == current){
+			qunlock(current);
+			break;
+		}
+		goto Reset;
 	case Cnext:
 		forward = 1;
 		showpage(nextpage(current));