shithub: gefs

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tree: fix scans in subtle edge case

if the value was the last value in a block,
and there were mulitple queued messages to
a value, and we did a btenter that touched
these, then we might not walk past all the
messages we wanted to; fix this, and clean
up the code a bit.

--- a/tree.c

+++ b/tree.c

@@ -1390,9 +1390,9 @@

 {

 	int i, same;

 	Scanp *p;

+	Msg m, c;

 	Bptr bp;

 	Blk *b;

-	Msg m;

 	Kvp v;

 	if(s->done)

@@ -1414,8 +1414,8 @@

 				p[i].bi++;

 				/* scan past repeated messages */

 				while(p[i].bi < p[i].b->nbuf){

-					getmsg(p[i].b, p[i].bi, &m);

-					if(keycmp(&m, &s->kv) >= 0)

+					getmsg(p[i].b, p[i].bi, &c);

+					if(keycmp(&m, &c) != 0)

 						break;

 					p[i].bi++;

 				}

@@ -1434,20 +1434,20 @@

 char *

 btnext(Scan *s, Kvp *r)

 {

-	int i, j, h, ok, start, srcbuf;

+	int i, j, h, ok, start, bufsrc;

 	Scanp *p;

 	Msg m, n;

 	Bptr bp;

 	Kvp kv;

-	/* load up the correct blocks for the scan */

 Again:

 	p = s->path;

 	h = s->ht;

 	start = h;

-	srcbuf = -1;

+	bufsrc = -1;

 	if(s->done)

 		return nil;

+	/* load up the correct blocks for the scan */

 	for(i = h-1; i >= 0; i--){

 		if(p[i].b != nil

 		&&(p[i].vi < p[i].b->nval || p[i].bi < p[i].b->nbuf))

@@ -1474,12 +1474,12 @@

 		}

 		/* find the minimum key along the path up */

-		m.op = Onop;

+		m.op = Oinsert;

 		getval(p[h-1].b, p[h-1].vi, &m);

 	}else{

 		getmsg(p[start-1].b, p[start-1].bi, &m);

 		assert(m.op == Oinsert);

-		srcbuf = start-1;

+		bufsrc = start-1;

 	}

 	for(i = h-2; i >= 0; i--){

@@ -1487,7 +1487,7 @@

 			continue;

 		getmsg(p[i].b, p[i].bi, &n);

 		if(keycmp(&n, &m) < 0){

-			srcbuf = i;

+			bufsrc = i;

 			m = n;

 		}

 	}

@@ -1499,10 +1499,10 @@

 	/* scan all messages applying to the message */

 	ok = 1;

 	cpkvp(r, &m, s->kvbuf, sizeof(s->kvbuf));

-	if(srcbuf == -1)

+	if(bufsrc == -1)

 		p[h-1].vi++;

 	else

-		p[srcbuf].bi++;

+		p[bufsrc].bi++;

 	for(i = h-2; i >= 0; i--){

 		for(j = p[i].bi; j < p[i].b->nbuf; j++){

 			getmsg(p[i].b, j, &m);