From 1757359fbf3df32d9cb4f438b55d9736882dbb41 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Mon, 4 Nov 2019 21:41:42 -0800
Subject: [PATCH] Fix "server busy" pairing error dialog

---
 Limelight/Network/PairManager.h                     |  6 +-----
 Limelight/Network/PairManager.m                     | 10 ++++++----
 Limelight/ViewControllers/MainFrameViewController.m |  6 ++++--
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/Limelight/Network/PairManager.h b/Limelight/Network/PairManager.h
index c137ff45..2cc29d2b 100644
--- a/Limelight/Network/PairManager.h
+++ b/Limelight/Network/PairManager.h
@@ -10,7 +10,7 @@
 
 @protocol PairCallback <NSObject>
 
-- (void) showPIN:(NSString*)PIN;
+- (void) startPairing:(NSString*)PIN;
 - (void) pairSuccessful:(NSData*)serverCert;
 - (void) pairFailed:(NSString*)message;
 - (void) alreadyPaired;
@@ -19,8 +19,4 @@
 
 @interface PairManager : NSOperation
 - (id) initWithManager:(HttpManager*)httpManager clientCert:(NSData*)clientCert callback:(id<PairCallback>)callback;
-- (NSString*) generatePIN;
-- (NSData*) saltPIN:(NSString*)PIN;
-- (void) initiatePair:(int)serverMajorVersion;
-
 @end
diff --git a/Limelight/Network/PairManager.m b/Limelight/Network/PairManager.m
index 6bce3599..2aa19188 100644
--- a/Limelight/Network/PairManager.m
+++ b/Limelight/Network/PairManager.m
@@ -30,6 +30,10 @@
 }
 
 - (void) main {
+    // We have to call startPairing before calling any other _callback functions
+    NSString* PIN = [self generatePIN];
+    [_callback startPairing:PIN];
+    
     ServerInfoResponse* serverInfoResp = [[ServerInfoResponse alloc] init];
     [_httpManager executeRequestSynchronously:[HttpRequest requestForResponse:serverInfoResp withUrlRequest:[_httpManager newServerInfoRequest:false]
                                                fallbackError:401 fallbackRequest:[_httpManager newHttpServerInfoRequest]]];
@@ -42,7 +46,7 @@
                 [_callback pairFailed:@"Missing XML element"];
                 return;
             }            
-            [self initiatePair: [[appversion substringToIndex:1] intValue]];
+            [self initiatePairWithPin:PIN forServerMajorVersion:[[appversion substringToIndex:1] intValue]];
         } else {
             [_callback alreadyPaired];
         }
@@ -78,7 +82,7 @@
 }
 
 // All codepaths must call finishPairing exactly once before returning!
-- (void) initiatePair:(int)serverMajorVersion {
+- (void) initiatePairWithPin:(NSString*)PIN forServerMajorVersion:(int)serverMajorVersion {
     Log(LOG_I, @"Pairing with generation %d server", serverMajorVersion);
     
     // Start a background task to help prevent the app from being killed
@@ -87,10 +91,8 @@
         Log(LOG_W, @"Background pairing time has expired!");
     }];
     
-    NSString* PIN = [self generatePIN];
     NSData* salt = [self saltPIN:PIN];
     Log(LOG_I, @"PIN: %@, saltedPIN: %@", PIN, salt);
-    [_callback showPIN:PIN];
     
     HttpResponse* pairResp = [[HttpResponse alloc] init];
     [_httpManager executeRequestSynchronously:[HttpRequest requestForResponse:pairResp withUrlRequest:[_httpManager newPairRequest:salt clientCert:_clientCert]]];
diff --git a/Limelight/ViewControllers/MainFrameViewController.m b/Limelight/ViewControllers/MainFrameViewController.m
index 8714c46e..13f02b88 100644
--- a/Limelight/ViewControllers/MainFrameViewController.m
+++ b/Limelight/ViewControllers/MainFrameViewController.m
@@ -56,8 +56,10 @@
 }
 static NSMutableSet* hostList;
 
-- (void)showPIN:(NSString *)PIN {
-    dispatch_async(dispatch_get_main_queue(), ^{
+- (void)startPairing:(NSString *)PIN {
+    // Needs to be synchronous to ensure the alert is shown before any potential
+    // failure callback could be invoked.
+    dispatch_sync(dispatch_get_main_queue(), ^{
         self->_pairAlert = [UIAlertController alertControllerWithTitle:@"Pairing"
                                                                message:[NSString stringWithFormat:@"Enter the following PIN on the host machine: %@", PIN]
                                                         preferredStyle:UIAlertControllerStyleAlert];