Ugly parser fix for multiple concurrent parsers using the bufferPool

Author: Ruben Bridgewater

lib/parser.js

@@ -137,7 +137,6 @@ function parseBulkString (parser) {
     parser.bigStrSize = offsetEnd + 2
     parser.bigOffset = parser.offset
     parser.totalChunkSize = parser.buffer.length
-    parser.bufferCache.push(parser.buffer)
     return
   }
 
@@ -348,20 +347,20 @@ JavascriptRedisParser.prototype.execute = function (buffer) {
     this.offset = 0
   } else if (this.bigStrSize === 0) {
     var oldLength = this.buffer.length
-    var remainingLength = oldLength - this.offset
-    var newLength = remainingLength + buffer.length
+    var newLength = oldLength + buffer.length
     // ~ 5% speed increase over using new Buffer(length) all the time
     if (bufferPool.length < newLength) { // We can't rely on the chunk size
       bufferPool = new Buffer(newLength)
     }
-    this.buffer.copy(bufferPool, 0, this.offset, oldLength)
-    buffer.copy(bufferPool, remainingLength, 0, buffer.length)
+    this.buffer.copy(bufferPool, 0, 0, oldLength)
+    buffer.copy(bufferPool, oldLength, 0, buffer.length)
     this.buffer = bufferPool.slice(0, newLength)
     this.offset = 0
   } else if (this.totalChunkSize + buffer.length >= this.bigStrSize) {
+    this.bufferCache.unshift(this.buffer)
     this.bufferCache.push(buffer)
     // The returned type might be Array * (42) and in that case we can't improve the parsing currently
-    if (this.optionReturnBuffers === false && this.buffer[this.offset] === 36) {
+    if (this.optionReturnBuffers === false && this.buffer[0] === 36) {
       this.returnReply(concatBulkString(this))
       this.buffer = buffer
     } else { // This applies for arrays too
@@ -382,7 +381,18 @@ JavascriptRedisParser.prototype.execute = function (buffer) {
     var type = this.buffer[this.offset++]
     var response = parseType(this, type)
     if (response === undefined) {
-      this.offset = offset
+      if (this.buffer === null) {
+        return
+      }
+      var tempBuffer = new Buffer(this.buffer.length - offset)
+      this.buffer.copy(tempBuffer, 0, offset, this.buffer.length)
+      this.buffer = tempBuffer
+      if (this.bigStrSize !== 0) {
+        this.bigStrSize -= offset
+        this.bigOffset -= offset
+        this.totalChunkSize -= offset
+      }
+      this.offset = 0
       return
     }