From 9d4f34bb7c5c53914411ae2244e70748b186bf8e Mon Sep 17 00:00:00 2001
From: Maurice Parker <mo@vincode.io>
Date: Tue, 21 Jul 2020 18:20:13 -0500
Subject: [PATCH] Only let one process renew the access token at a time for
 Reddit

---
 .../Reddit/RedditFeedProvider.swift           | 21 ++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/Frameworks/Account/FeedProvider/Reddit/RedditFeedProvider.swift b/Frameworks/Account/FeedProvider/Reddit/RedditFeedProvider.swift
index b293e69f8..0800e63c9 100644
--- a/Frameworks/Account/FeedProvider/Reddit/RedditFeedProvider.swift
+++ b/Frameworks/Account/FeedProvider/Reddit/RedditFeedProvider.swift
@@ -50,6 +50,7 @@ public final class RedditFeedProvider: FeedProvider {
 	
 	public var username: String?
 	
+	private var refreshingAuthToken = false
 	private var oauthToken: String
 	private var oauthRefreshToken: String
 
@@ -410,27 +411,37 @@ private extension RedditFeedProvider {
     func handleFailure(error: OAuthSwiftError, completion: @escaping (Error?) -> Void) {
 		if case .tokenExpired = error {
 
+			if refreshingAuthToken {
+				DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
+					completion(nil)
+				}
+			}
+			
+			refreshingAuthToken = true
 			os_log(.debug, log: self.log, "Access token expired, attempting to renew...")
 			
 			oauthSwift?.renewAccessToken(withRefreshToken: oauthRefreshToken) { [weak self] result in
-				guard let strongSelf = self, let username = strongSelf.username else {
+				guard let self = self, let username = self.username else {
 					completion(nil)
 					return
 				}
 				
 				switch result {
 				case .success(let tokenSuccess):
-					strongSelf.oauthToken = tokenSuccess.credential.oauthToken
-					strongSelf.oauthRefreshToken = tokenSuccess.credential.oauthRefreshToken
+					self.oauthToken = tokenSuccess.credential.oauthToken
+					self.oauthRefreshToken = tokenSuccess.credential.oauthRefreshToken
 					do {
-						try Self.storeCredentials(username: username, oauthToken: strongSelf.oauthToken, oauthRefreshToken: strongSelf.oauthRefreshToken)
-						os_log(.debug, log: strongSelf.log, "Access token renewed.")
+						try Self.storeCredentials(username: username, oauthToken: self.oauthToken, oauthRefreshToken: self.oauthRefreshToken)
+						os_log(.debug, log: self.log, "Access token renewed.")
 					} catch {
+						self.refreshingAuthToken = false
 						completion(error)
 						return
 					}
+					self.refreshingAuthToken = false
 					completion(nil)
 				case .failure(let oathError):
+					self.refreshingAuthToken = false
 					completion(oathError)
 				}
 			}