From 698b07b074dc554578ecddd138972702f46d0879 Mon Sep 17 00:00:00 2001
From: Ben Johnson <benbjohnson@yahoo.com>
Date: Mon, 7 Apr 2014 16:24:51 -0600
Subject: Add nested buckets.

This commit adds the ability to create buckets inside of other buckets.
It also replaces the buckets page with a root bucket.

Fixes #56.
---
 freelist.go | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

(limited to 'freelist.go')

diff --git a/freelist.go b/freelist.go
index cb58a54..ebe2810 100644
--- a/freelist.go
+++ b/freelist.go
@@ -62,6 +62,8 @@ func (f *freelist) free(txid txid, p *page) {
 		ids = append(ids, p.id+pgid(i))
 	}
 	f.pending[txid] = ids
+
+	// DEBUG ONLY: f.check()
 }
 
 // release moves all page ids for a transaction id (or older) to the freelist.
@@ -109,6 +111,29 @@ func (f *freelist) write(p *page) {
 	copy(((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[:], ids)
 }
 
+// check verifies there are no double free pages.
+// This is slow so it should only be used while debugging.
+// If errors are found then a panic invoked.
+/*
+func (f *freelist) check() {
+	var lookup = make(map[pgid]txid)
+	for _, id := range f.ids {
+		if _, ok := lookup[id]; ok {
+			panic(fmt.Sprintf("page %d already freed", id))
+		}
+		lookup[id] = 0
+	}
+	for txid, m := range f.pending {
+		for _, id := range m {
+			if _, ok := lookup[id]; ok {
+				panic(fmt.Sprintf("tx %d: page %d already freed in tx %d", txid, id, lookup[id]))
+			}
+			lookup[id] = txid
+		}
+	}
+}
+*/
+
 type reverseSortedPgids []pgid
 
 func (s reverseSortedPgids) Len() int           { return len(s) }
-- 
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