From b65ed25b29788f3f66ec25a7291bac5e2ba0e7d7 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Thu, 21 Jan 2016 03:48:39 -0800
Subject: [PATCH] chaindb: fix async.

---
 lib/bcoin/chain.js | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index 161bdadd..7a921dbb 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -714,7 +714,6 @@ function ChainDB(chain, options) {
   this.tip = -1;
   this.size = 0;
   this.fd = null;
-  this._writing = 0;
 
   // Need to cache up to the retarget interval
   // if we're going to be checking the damn
@@ -863,7 +862,6 @@ ChainDB.prototype.saveAsync = function save(entry, callback) {
   // Speed up writes by doing them asynchronously
   // and keeping the data to be written in memory.
   this._queue[entry.height] = entry;
-  this._writing++;
 
   // Write asynchronously to the db.
   raw = entry.toRaw();
@@ -877,14 +875,13 @@ ChainDB.prototype.saveAsync = function save(entry, callback) {
     // Something tried to write here but couldn't.
     // Synchronously write it and get it over with.
     try {
-      if (item !== entry)
+      if (item && item !== entry)
         success = self._write(item.toRaw(), offset);
     } catch (e) {
       err = e;
     }
 
     delete self._queue[entry.height];
-    self._writing--;
 
     if (err) {
       if (callback)
@@ -901,7 +898,13 @@ ChainDB.prototype.saveAsync = function save(entry, callback) {
 ChainDB.prototype.remove = function remove(height) {
   assert(height >= 0);
 
+  if (this._queue[height]) {
+    utils.debug('Warning: write job in progress.');
+    delete this._queue[height];
+  }
+
   this._write(this._nullBlock, height * BLOCK_SIZE);
+  delete this._cache[height];
 
   // If we deleted several blocks at the end, go back
   // to the last non-null block and truncate the file
@@ -959,6 +962,8 @@ ChainDB.prototype._writeAsync = function _writeAsync(data, offset, callback) {
   if (offset < 0 || offset == null)
     return false;
 
+  self.size += added;
+
   (function callee() {
     fs.write(self.fd, data, index, size, offset, function(err, bytes) {
       if (err)
@@ -968,10 +973,8 @@ ChainDB.prototype._writeAsync = function _writeAsync(data, offset, callback) {
       size -= bytes;
       offset += bytes;
 
-      if (index === data.length) {
-        self.size += added;
+      if (index === data.length)
         return callback(null, true);
-      }
 
       callee();
     });