prepare for multiplexed snowflake (#11)

proxy/broker.coffee

@@ -33,7 +33,7 @@ class Broker
     @url += '/' if '/' != @url.substr -1
 
   # Promises some client SDP Offer.
-  # Registers this Snowfalke with the broker using an HTTP POST request, and
+  # Registers this Snowflake with the broker using an HTTP POST request, and
   # waits for a response containing some client offer that the Broker chooses
   # for this proxy..
   # TODO: Actually support multiple clients.

proxy/proxypair.coffee

@@ -8,15 +8,17 @@ Represents a single:
 class ProxyPair
 
   MAX_BUFFER: 10 * 1024 * 1024
-  pc: null
+  pc:          null
   c2rSchedule: []
   r2cSchedule: []
-  client: null  # WebRTC Data channel
-  relay: null   # websocket
-  running: true
+  client:      null  # WebRTC Data channel
+  relay:       null   # websocket
+  running:     true
+  active:      false  # Whether serving a client.
   flush_timeout_id: null
 
   constructor: (@clientAddr, @relayAddr, @rateLimit) ->
+    @active = false
 
   # Prepare a WebRTC PeerConnection and await for an SDP offer.
   begin: ->
@@ -51,6 +53,7 @@ class ProxyPair
       log 'Invalid SDP message.'
       return false
     dbg 'SDP ' + offer.type + ' successfully received.'
+    @active = true
     true
 
   prepareDataChannel: (channel) =>

proxy/snowflake.coffee

@@ -51,10 +51,7 @@ CONFIRMATION_MESSAGE = "You're currently serving a Tor user via Snowflake."
 class Snowflake
 
   relayAddr: null
-  # TODO: Actually support multiple ProxyPairs. (makes more sense once meek-
-  # signalling is ready)
   proxyPairs: []
-  proxyPair: null
 
   rateLimit: null
   state: MODE.INIT
@@ -86,7 +83,6 @@ class Snowflake
     @state = MODE.WEBRTC_CONNECTING
     for i in [1..CONNECTIONS_PER_CLIENT]
       @makeProxyPair @relayAddr
-    @proxyPair = @proxyPairs[0]
     return if COPY_PASTE_ENABLED
     timer = null
     # Temporary countdown.
@@ -114,17 +110,19 @@ class Snowflake
 
     findClients()
 
-  # Receive an SDP offer from some client assigned by the Broker.
+  # Receive an SDP offer from some client assigned by the Broker,
   receiveOffer: (desc) =>
     sdp = new RTCSessionDescription desc
-    if @proxyPair.receiveWebRTCOffer sdp
-      @sendAnswer() if 'offer' == sdp.type
+    # Use the first proxyPair that's available.
+    pair = @proxyPairs.find (pp, i, arr) -> return !pp.active
+    if pair.receiveWebRTCOffer sdp
+      @sendAnswer pair if 'offer' == sdp.type
 
-  sendAnswer: =>
-    next = (sdp) =>
+  sendAnswer: (pair) ->
+    next = (sdp) ->
       dbg 'webrtc: Answer ready.'
-      @proxyPair.pc.setLocalDescription sdp
-    promise = @proxyPair.pc.createAnswer next
+      pair.pc.setLocalDescription sdp
+    promise = pair.pc.createAnswer next
     promise.then next if promise
 
   makeProxyPair: (relay) ->

proxy/spec/snowflake.spec.coffee

@@ -49,10 +49,10 @@ describe 'Snowflake', ->
 
   it 'receives SDP offer', ->
     s = new Snowflake(new FakeBroker(), fakeUI)
-    s.proxyPair = { receiveWebRTCOffer: -> }
-    spyOn(s.proxyPair, 'receiveWebRTCOffer').and.returnValue true
+    s.proxyPairs[0] = { receiveWebRTCOffer: -> }
+    spyOn(s.proxyPairs[0], 'receiveWebRTCOffer').and.returnValue true
     spyOn(s, 'sendAnswer')
-    s.receiveOffer 'foo'
+    s.receiveOffer { 'type': 'offer', 'sdp': 'foo' }
     expect(s.sendAnswer).toHaveBeenCalled()
 
   it 'can make a proxypair', ->