Add a varint-delimiting stream as well.

lib/wire/messagestream.js

@@ -1,7 +1,7 @@
 var util = require('util')
 var stream = require('stream')
 
-function MessageStream() {
+function DelimitedStream() {
   stream.Transform.call(this)
   this._length = 0
   this._lengthIndex = 0
@@ -9,9 +9,9 @@ function MessageStream() {
   this._buffer = new Buffer(0)
 }
 
-util.inherits(MessageStream, stream.Transform)
+util.inherits(DelimitedStream, stream.Transform)
 
-MessageStream.prototype._transform = function(chunk, encoding, done) {
+DelimitedStream.prototype._transform = function(chunk, encoding, done) {
   this._buffer = Buffer.concat([this._buffer, chunk])
 
   var lo = 0
@@ -49,4 +49,34 @@ MessageStream.prototype._transform = function(chunk, encoding, done) {
   done()
 }
 
-module.exports = MessageStream
+module.exports.DelimitedStream = DelimitedStream
+
+function DelimitingStream() {
+  stream.Transform.call(this)
+}
+
+util.inherits(DelimitingStream, stream.Transform)
+
+DelimitingStream.prototype._transform = function(chunk, encoding, done) {
+  var length = chunk.length
+  var lengthBytes = []
+  var more = true
+
+  while (more) {
+    if (length > 0x7f) {
+      lengthBytes.push((1 << 7) + (length & 0x7f))
+      length >>= 7
+    }
+    else {
+      lengthBytes.push(length)
+      more = false
+    }
+  }
+
+  this.push(new Buffer(lengthBytes))
+  this.push(chunk)
+
+  done()
+}
+
+module.exports.DelimitingStream = DelimitingStream

test/wire/messagestream.js

@@ -3,52 +3,91 @@ var chai = require('chai')
 chai.use(require('sinon-chai'))
 var expect = chai.expect
 
-var MessageStream = require('../../lib/wire/messagestream')
+var ms = require('../../lib/wire/messagestream')
 
 describe('MessageStream', function() {
-  it('should emit complete varint32-delimited chunks', function() {
-    var ms = new MessageStream()
-    var spy = sinon.spy()
-    ms.on('data', spy)
-    ms.write(new Buffer([1, 0x61, 2, 0x62, 0x63]))
-    expect(spy).to.have.been.calledTwice
-    expect(spy.firstCall.args).to.eql([new Buffer([0x61])])
-    expect(spy.secondCall.args).to.eql([new Buffer([0x62, 0x63])])
+  describe('DelimitedStream', function() {
+    it('should emit complete varint-delimited chunks', function() {
+      var ds = new ms.DelimitedStream()
+      var spy = sinon.spy()
+      ds.on('data', spy)
+      ds.write(new Buffer([1, 0x61, 2, 0x62, 0x63]))
+      expect(spy).to.have.been.calledTwice
+      expect(spy.firstCall.args).to.eql([new Buffer([0x61])])
+      expect(spy.secondCall.args).to.eql([new Buffer([0x62, 0x63])])
+    })
+
+    it('should wait for more data', function() {
+      var ds = new ms.DelimitedStream()
+      var spy = sinon.spy()
+      ds.on('data', spy)
+      ds.write(new Buffer([1]))
+      expect(spy).to.not.have.been.called
+      ds.write(new Buffer([0x66]))
+      expect(spy).to.have.been.calledOnce
+      expect(spy.firstCall.args).to.eql([new Buffer([0x66])])
+    })
+
+    it('should read varint32 properly', function() {
+      var ds = new ms.DelimitedStream()
+      var spy = sinon.spy()
+      ds.on('data', spy)
+      ds.write(new Buffer([172, 2])) // 300
+      var data = new Buffer(300)
+      data.fill(0)
+      ds.write(data)
+      expect(spy).to.have.been.calledOnce
+      expect(spy.firstCall.args).to.eql([data])
+    })
+
+    it('should emit "end"', function(done) {
+      var ds = new ms.DelimitedStream()
+      var spy = sinon.spy()
+      ds.on('data', sinon.spy())
+      ds.on('end', spy)
+      ds.write(new Buffer([1]))
+      ds.end()
+      setImmediate(function() {
+        expect(spy).to.have.been.called
+        done()
+      })
+    })
   })
 
-  it('should wait for more data', function() {
-    var ms = new MessageStream()
-    var spy = sinon.spy()
-    ms.on('data', spy)
-    ms.write(new Buffer([1]))
-    expect(spy).to.not.have.been.called
-    ms.write(new Buffer([0x66]))
-    expect(spy).to.have.been.calledOnce
-    expect(spy.firstCall.args).to.eql([new Buffer([0x66])])
-  })
+  describe('DelimitingStream', function() {
+    it('should add delimiter chunks to stream', function() {
+      var ds = new ms.DelimitingStream()
+      var spy = sinon.spy()
+      ds.on('data', spy)
+      ds.write(new Buffer([0x66, 0x6f, 0x6f]))
+      expect(spy).to.have.been.calledTwice
+      expect(spy.firstCall.args).to.eql([new Buffer([0x03])])
+      expect(spy.secondCall.args).to.eql([new Buffer([0x66, 0x6f, 0x6f])])
+    })
 
-  it('should read varint32 properly', function() {
-    var ms = new MessageStream
-    var spy = sinon.spy()
-    ms.on('data', spy)
-    ms.write(new Buffer([172, 2])) // 300
-    var data = new Buffer(300)
-    data.fill(0)
-    ms.write(data)
-    expect(spy).to.have.been.calledOnce
-    expect(spy.firstCall.args).to.eql([data])
-  })
+    it('should write proper varints', function() {
+      var ds = new ms.DelimitingStream()
+      var spy = sinon.spy()
+      ds.on('data', spy)
+      var data = new Buffer(300)
+      data.fill(0)
+      ds.write(data)
+      expect(spy).to.have.been.calledTwice
+      expect(spy.firstCall.args).to.eql([new Buffer([172, 2])])
+      expect(spy.secondCall.args).to.eql([data])
+    })
 
-  it('should emit "end"', function(done) {
-    var ms = new MessageStream()
-    var spy = sinon.spy()
-    ms.on('data', sinon.spy())
-    ms.on('end', spy)
-    ms.write(new Buffer([1]))
-    ms.end()
-    setImmediate(function() {
-      expect(spy).to.have.been.called
-      done()
+    it('should emit "end"', function(done) {
+      var ds = new ms.DelimitingStream()
+      var spy = sinon.spy()
+      ds.on('data', sinon.spy())
+      ds.on('end', spy)
+      ds.write(new Buffer([1]))
+      ds.end()
+      setImmediate(function() {
+        expect(spy).to.have.been.called
+        done()
+      })
     })
   })
 })