Send ICE updates immediately after sending CallOffer for faster call

connection.

For legacy reasons, the call sender used to wait until after receiving
the call answer before sending the ICE updates. The primary motivation
was that if the receiving user hadn't accepted a new identity change,
rather than just seeing one "Tap to Accept New Safety Number" messages
for a call, they'd see one for the call offer and then a dozen more as
ICE updates trickled in.

We changed that behavior long ago, and effectively all clients will
avoid that case, while sending ICE updates immediately will allow calls
to connect without having to wait for an additional serialized round
trip between the caller and call recipient.

// FREEBIE

Signal/src/call/CallService.swift

@@ -163,17 +163,6 @@ protocol CallServiceObserver: class {
     private var fulfillCallConnectedPromise: (() -> Void)?
     private var rejectCallConnectedPromise: ((Error) -> Void)?
 
-    /**
-     * In the process of establishing a connection between the clients (ICE process) we must exchange ICE updates.
-     * Because this happens via Signal Service it's possible the callee user has not accepted any change in the caller's 
-     * identity. In which case *each* ICE update would cause an "identity change" warning on the callee's device. Since
-     * this could be several messages, the caller stores all ICE updates until receiving positive confirmation that the 
-     * callee has received a message from us. This positive confirmation comes in the form of the callees `CallAnswer` 
-     * message.
-     */
-    var sendIceUpdatesImmediately = true
-    var pendingIceUpdateMessages = [OWSCallIceUpdateMessage]()
-
     // Used by waitForPeerConnectionClient to make sure any received
     // ICE messages wait until the peer connection client is set up.
     private var fulfillPeerConnectionClientPromise: (() -> Void)?
@@ -283,9 +272,6 @@ protocol CallServiceObserver: class {
 
         self.call = call
 
-        sendIceUpdatesImmediately = false
-        pendingIceUpdateMessages = []
-
         let callRecord = TSCall(timestamp: NSDate.ows_millisecondTimeStamp(), withCallNumber: call.remotePhoneNumber, callType: RPRecentCallTypeOutgoingIncomplete, in: call.thread)
         callRecord.save()
         call.callRecord = callRecord
@@ -405,19 +391,6 @@ protocol CallServiceObserver: class {
             return
         }
 
-        // Now that we know the recipient trusts our identity, we no longer need to enqueue ICE updates.
-        self.sendIceUpdatesImmediately = true
-
-        if pendingIceUpdateMessages.count > 0 {
-            Logger.error("\(self.logTag) Sending \(pendingIceUpdateMessages.count) pendingIceUpdateMessages")
-
-            let callMessage = OWSOutgoingCallMessage(thread: thread, iceUpdateMessages: pendingIceUpdateMessages)
-            let sendPromise = messageSender.sendPromise(message: callMessage).catch { error in
-                Logger.error("\(self.logTag) failed to send ice updates in \(#function) with error: \(error)")
-            }
-            sendPromise.retainUntilComplete()
-        }
-
         guard let peerConnectionClient = self.peerConnectionClient else {
             OWSProdError(OWSAnalyticsEvents.callServicePeerConnectionMissing(), file: #file, function: #function, line: #line)
             handleFailedCall(failedCall: call, error: CallError.assertionError(description: "peerConnectionClient was unexpectedly nil in \(#function)"))
@@ -696,7 +669,7 @@ protocol CallServiceObserver: class {
             AssertIsOnMainThread()
 
             guard let call = self.call else {
-                Logger.warn("ignoring remote ice update for thread: \(thread.uniqueId) since there is no current call. Call already ended?")
+                Logger.warn("ignoring remote ice update for thread: \(String(describing: thread.uniqueId)) since there is no current call. Call already ended?")
                 return
             }
 
@@ -706,12 +679,12 @@ protocol CallServiceObserver: class {
             }
 
             guard thread.contactIdentifier() == call.thread.contactIdentifier() else {
-                Logger.warn("ignoring remote ice update for thread: \(thread.uniqueId) due to thread mismatch. Call already ended?")
+                Logger.warn("ignoring remote ice update for thread: \(String(describing: thread.uniqueId)) due to thread mismatch. Call already ended?")
                 return
             }
 
             guard let peerConnectionClient = self.peerConnectionClient else {
-                Logger.warn("ignoring remote ice update for thread: \(thread.uniqueId) since there is no current peerConnectionClient. Call already ended?")
+                Logger.warn("ignoring remote ice update for thread: \(String(describing: thread.uniqueId)) since there is no current peerConnectionClient. Call already ended?")
                 return
             }
 
@@ -753,19 +726,10 @@ protocol CallServiceObserver: class {
 
             let iceUpdateMessage = OWSCallIceUpdateMessage(callId: call.signalingId, sdp: iceCandidate.sdp, sdpMLineIndex: iceCandidate.sdpMLineIndex, sdpMid: iceCandidate.sdpMid)
 
-            if self.sendIceUpdatesImmediately {
+            Logger.info("\(self.logTag) in \(#function) sending ICE Candidate.")
-                Logger.info("\(self.logTag) in \(#function). Sending immediately.")
+            let callMessage = OWSOutgoingCallMessage(thread: call.thread, iceUpdateMessage: iceUpdateMessage)
-                let callMessage = OWSOutgoingCallMessage(thread: call.thread, iceUpdateMessage: iceUpdateMessage)
+            let sendPromise = self.messageSender.sendPromise(message: callMessage)
-                let sendPromise = self.messageSender.sendPromise(message: callMessage)
+            sendPromise.retainUntilComplete()
-                sendPromise.retainUntilComplete()
-            } else {
-                // For outgoing messages, we wait to send ice updates until we're sure client received our call message.
-                // e.g. if the client has blocked our message due to an identity change, we'd otherwise
-                // bombard them with a bunch *more* undecipherable messages.
-                Logger.info("\(self.logTag) in \(#function). Enqueing for later.")
-                self.pendingIceUpdateMessages.append(iceUpdateMessage)
-                return
-            }
         }.catch { error in
             OWSProdInfo(OWSAnalyticsEvents.callServiceErrorHandleLocalAddedIceCandidate(), file: #file, function: #function, line: #line)
             Logger.error("\(self.logTag) in \(#function) waitUntilReadyToSendIceUpdates failed with error: \(error)")
@@ -1503,9 +1467,6 @@ protocol CallServiceObserver: class {
         self.callUIAdapter.didTerminateCall(self.call)
         self.call = nil
 
-        self.sendIceUpdatesImmediately = true
-        Logger.info("\(self.logTag) clearing pendingIceUpdateMessages")
-        self.pendingIceUpdateMessages = []
         self.fulfillCallConnectedPromise = nil
 
         // In case we're still waiting on this promise somewhere, we need to reject it to avoid a memory leak.

Signal/src/call/PeerConnectionClient.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -657,7 +657,7 @@ class PeerConnectionClient: NSObject, RTCPeerConnectionDelegate, RTCDataChannelD
                 Logger.debug("\(self.TAG) \(#function) Ignoring obsolete event in terminated client")
                 return
             }
-            Logger.debug("\(self.TAG) didChange IceConnectionState:\(newState.debugDescription)")
+            Logger.info("\(self.TAG) didChange IceConnectionState:\(newState.debugDescription)")
             switch newState {
             case .connected, .completed:
                 if let delegate = self.delegate {
@@ -684,7 +684,7 @@ class PeerConnectionClient: NSObject, RTCPeerConnectionDelegate, RTCDataChannelD
 
     /** Called any time the IceGatheringState changes. */
     internal func peerConnection(_ peerConnection: RTCPeerConnection, didChange newState: RTCIceGatheringState) {
-        Logger.debug("\(TAG) didChange IceGatheringState:\(newState.debugDescription)")
+        Logger.info("\(TAG) didChange IceGatheringState:\(newState.debugDescription)")
     }
 
     /** New ice candidate has been found. */
@@ -716,7 +716,7 @@ class PeerConnectionClient: NSObject, RTCPeerConnectionDelegate, RTCDataChannelD
                 Logger.debug("\(self.TAG) \(#function) Ignoring obsolete event in terminated client")
                 return
             }
-            Logger.debug("\(self.TAG) didOpen dataChannel:\(dataChannel)")
+            Logger.info("\(self.TAG) didOpen dataChannel:\(dataChannel)")
             assert(self.dataChannel == nil)
             self.dataChannel = dataChannel
             dataChannel.delegate = self