Intermediate fix js parser handling big values very slow

Closes #900

Author: Ruben Bridgewater

changelog.md

@@ -1,6 +1,13 @@
 Changelog
 =========
 
+## v.2.3.1 - xx Nov, 2015
+
+Bugfixes
+
+-  Fixed js parser handling big values very slow ([@BridgeAR](https://github.com/BridgeAR))
+ -  The speed is up to ~500% faster than before but still up to ~50% slower than the hiredis parser.
+
 ## v.2.3.0 - 30 Oct, 2015
 
 Features

index.js

@@ -733,7 +733,7 @@ RedisClient.prototype.send_command = function (command, args, callback) {
             buffer_args = true;
         } else if (typeof args[i] !== 'string') {
             args[i] = String(args[i]);
-        // 30000 seemed to be a good value to switch to buffers after testing this with and checking the pros and cons
+        // 30000 seemed to be a good value to switch to buffers after testing and checking the pros and cons
         } else if (args[i].length > 30000) {
             big_data = true;
             args[i] = new Buffer(args[i]);

lib/parsers/javascript.js

@@ -1,11 +1,12 @@
 'use strict';
 
-var util   = require('util');
+var util = require('util');
 
 function JavascriptReplyParser() {
     this.name = exports.name;
-    this._buffer            = new Buffer(0);
-    this._offset            = 0;
+    this._buffer = new Buffer(0);
+    this._offset = 0;
+    this._buffers = [];
 }
 
 function IncompleteReadBuffer(message) {
@@ -66,7 +67,7 @@ JavascriptReplyParser.prototype._parseResult = function (type) {
             return null;
         }
 
-        if (packetHeader > this._bytesRemaining()) {
+        if (packetHeader > this._buffer.length - this._offset) {
             this._offset = offset - 1;
             throw new IncompleteReadBuffer('Wait for more data.');
         }
@@ -93,14 +94,37 @@ JavascriptReplyParser.prototype._parseResult = function (type) {
 };
 
 JavascriptReplyParser.prototype.execute = function (buffer) {
-    this.append(buffer);
+    var i = buffer.length - 1;
+
+    while (buffer[i] !== 0x0a) {
+        i--;
+        if (i < 1) {
+            this._buffers.push(buffer);
+            return;
+        }
+    }
+
+    if (this._buffers.length !== 0) {
+        this._buffers.unshift(this._offset === 0 ? this._buffer : this._buffer.slice(this._offset));
+        this._buffers.push(buffer);
+        this._buffer = Buffer.concat(this._buffers);
+        this._buffers = [];
+    } else if (this._offset >= this._buffer.length) {
+        this._buffer = buffer;
+    } else {
+        this._buffer = Buffer.concat([this._buffer.slice(this._offset), buffer]);
+    }
+    this._offset = 0;
+    this.run();
+};
 
-    var type, offset;
+JavascriptReplyParser.prototype.run = function (buffer) {
+    var type, offset = this._offset;
 
     while (true) {
         offset = this._offset;
         // at least 4 bytes: :1\r\n
-        if (this._bytesRemaining() < 4) {
+        if (this._buffer.length - this._offset < 4) {
             break;
         }
 
@@ -109,7 +133,7 @@ JavascriptReplyParser.prototype.execute = function (buffer) {
 
             if (type === 43 || type === 58 || type === 36) { // Strings + // Integers : // Bulk strings $
                 this.send_reply(this._parseResult(type));
-            } else  if (type === 45) { // Errors -
+            } else if (type === 45) { // Errors -
                 this.send_error(this._parseResult(type));
             } else if (type === 42) { // Arrays *
                 // set a rewind point. if a failure occurs,
@@ -130,24 +154,11 @@ JavascriptReplyParser.prototype.execute = function (buffer) {
     }
 };
 
-JavascriptReplyParser.prototype.append = function (newBuffer) {
-
-    // out of data
-    if (this._offset >= this._buffer.length) {
-        this._buffer = newBuffer;
-        this._offset = 0;
-        return;
-    }
-
-    this._buffer = Buffer.concat([this._buffer.slice(this._offset), newBuffer]);
-    this._offset = 0;
-};
-
 JavascriptReplyParser.prototype.parseHeader = function () {
-    var end   = this._packetEndOffset() + 1,
-        value = this._buffer.toString('ascii', this._offset, end - 1) | 0;
+    var end   = this._packetEndOffset(),
+        value = this._buffer.toString('ascii', this._offset, end) | 0;
 
-    this._offset = end + 1;
+    this._offset = end + 2;
 
     return value;
 };
@@ -167,9 +178,5 @@ JavascriptReplyParser.prototype._packetEndOffset = function () {
     return offset;
 };
 
-JavascriptReplyParser.prototype._bytesRemaining = function () {
-    return (this._buffer.length - this._offset) < 0 ? 0 : (this._buffer.length - this._offset);
-};
-
 exports.Parser = JavascriptReplyParser;
 exports.name = 'javascript';

test/return_buffers.spec.js

@@ -261,7 +261,7 @@ describe("return_buffers", function () {
                         }
                     });
                 });
-                
+
                 it('receives buffer messages', function (done) {
                     sub.on("subscribe", function (chnl, count) {
                         pub.publish(channel, message);