From 35c8b97fbfd277cbb195486e29be17aba714a7b1 Mon Sep 17 00:00:00 2001
From: Wade Simmons <wade@wades.im>
Date: Fri, 27 Jun 2014 11:55:06 -0700
Subject: [PATCH] fix TFramedTransport residual continuation

There were many bugs in the current TFramedTransport.receiver caused by
merge mistakes and bad patches. Simplify the logic so it is easier to
reason about and prevent future issues.

- THRIFT-2194 Fixed one bug with residual not being set
- THRIFT-2205 Reverted the above fix (by accident) and broke it further
  by including InputBufferUnderrunError in TFramedTransport (which is
  incorrect)

This patch cleans up TFramedTransport.receiver by only have one hold
over buffer instead of two (frame + residual).
---
 lib/nodejs/lib/thrift/transport.js | 49 +++++++++++-------------------
 1 file changed, 18 insertions(+), 31 deletions(-)

diff --git a/lib/nodejs/lib/thrift/transport.js b/lib/nodejs/lib/thrift/transport.js
index 8423f897..900472c2 100644
--- a/lib/nodejs/lib/thrift/transport.js
+++ b/lib/nodejs/lib/thrift/transport.js
@@ -34,49 +34,36 @@ var TFramedTransport = exports.TFramedTransport = function(buffer, callback) {
   this.onFlush = callback;
 };
 TFramedTransport.receiver = function(callback) {
-  var frameLeft = 0,
-      framePos = 0,
-      frame = null;
   var residual = null;
 
   return function(data) {
     // Prepend any residual data from our previous read
     if (residual) {
-      var dat = new Buffer(data.length + residual.length);
-      residual.copy(dat, 0, 0);
-      data.copy(dat, residual.length, 0);
+      data = Buffer.concat([residual, data]);
       residual = null;
     }
 
     // framed transport
     while (data.length) {
-      if (frameLeft === 0) {
-        // TODO assumes we have all 4 bytes
-        if (data.length < 4) {
-          console.log("Expecting > 4 bytes, found only " + data.length);
-          residual = data;
-          throw new InputBufferUnderrunError();
-          //throw Error("Expecting > 4 bytes, found only " + data.length);
-        }
-        frameLeft = binary.readI32(data, 0);
-        frame = new Buffer(frameLeft);
-        framePos = 0;
-        data = data.slice(4, data.length);
+      if (data.length < 4) {
+        // Not enough bytes to continue, save and resume on next packet
+        residual = data;
+        return;
       }
-      
-      if (data.length >= frameLeft) {
-        data.copy(frame, framePos, 0, frameLeft);
-        data = data.slice(frameLeft, data.length);
-      
-        frameLeft = 0;
-        callback(new TFramedTransport(frame));
-      } else if (data.length) {
-        data.copy(frame, framePos, 0, data.length);
-        frameLeft -= data.length;
-        framePos += data.length;
-        data = data.slice(data.length, data.length);
-        throw new InputBufferUnderrunError();
+      var frameSize = binary.readI32(data, 0);
+      if (data.length < 4 + frameSize) {
+        // Not enough bytes to continue, save and resume on next packet
+        residual = data;
+        return;
       }
+
+      var frame = data.slice(4, 4 + frameSize);
+      residual = data.slice(4 + frameSize);
+
+      callback(new TFramedTransport(frame));
+
+      data = residual;
+      residual = null;
     }
   };
 };
-- 
2.17.1