From b57c99e4b3d3a9f51d09f5a00355512935f118bc Mon Sep 17 00:00:00 2001
From: JustArchi <JustArchi@JustArchi.net>
Date: Thu, 24 Oct 2019 19:09:57 +0200
Subject: [PATCH] Add safeguard against Steam pages reorder mid-parsing

---
 ArchiSteamFarm/CardsFarmer.cs | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/ArchiSteamFarm/CardsFarmer.cs b/ArchiSteamFarm/CardsFarmer.cs
index d8dbbccd0..0c3f91d5a 100755
--- a/ArchiSteamFarm/CardsFarmer.cs
+++ b/ArchiSteamFarm/CardsFarmer.cs
@@ -370,9 +370,9 @@ namespace ArchiSteamFarm {
 			await StartFarming().ConfigureAwait(false);
 		}
 
-		private async Task CheckPage(HtmlDocument htmlDocument) {
-			if (htmlDocument == null) {
-				Bot.ArchiLogger.LogNullError(nameof(htmlDocument));
+		private async Task CheckPage(HtmlDocument htmlDocument, ISet<uint> parsedAppIDs) {
+			if ((htmlDocument == null) || (parsedAppIDs == null)) {
+				Bot.ArchiLogger.LogNullError(nameof(htmlDocument) + " || " + nameof(parsedAppIDs));
 
 				return;
 			}
@@ -419,6 +419,11 @@ namespace ArchiSteamFarm {
 					continue;
 				}
 
+				if (!parsedAppIDs.Add(appID)) {
+					// Another task has already handled this appID
+					continue;
+				}
+
 				if (SalesBlacklist.Contains(appID) || ASF.GlobalConfig.Blacklist.Contains(appID) || Bot.IsBlacklistedFromIdling(appID) || (Bot.BotConfig.IdlePriorityQueueOnly && !Bot.IsPriorityIdling(appID))) {
 					// We're configured to ignore this appID, so skip it
 					continue;
@@ -680,9 +685,9 @@ namespace ArchiSteamFarm {
 			}
 		}
 
-		private async Task CheckPage(byte page) {
-			if (page == 0) {
-				Bot.ArchiLogger.LogNullError(nameof(page));
+		private async Task CheckPage(byte page, ISet<uint> parsedAppIDs) {
+			if ((page == 0) || (parsedAppIDs == null)) {
+				Bot.ArchiLogger.LogNullError(nameof(page) + " || " + nameof(parsedAppIDs));
 
 				return;
 			}
@@ -693,7 +698,7 @@ namespace ArchiSteamFarm {
 				return;
 			}
 
-			await CheckPage(htmlDocument).ConfigureAwait(false);
+			await CheckPage(htmlDocument, parsedAppIDs).ConfigureAwait(false);
 		}
 
 		private async Task Farm() {
@@ -999,7 +1004,9 @@ namespace ArchiSteamFarm {
 
 			GamesToFarm.Clear();
 
-			Task mainTask = CheckPage(htmlDocument);
+			ConcurrentHashSet<uint> parsedAppIDs = new ConcurrentHashSet<uint>();
+
+			Task mainTask = CheckPage(htmlDocument, parsedAppIDs);
 
 			switch (ASF.GlobalConfig.OptimizationMode) {
 				case GlobalConfig.EOptimizationMode.MinMemoryUsage:
@@ -1009,7 +1016,7 @@ namespace ArchiSteamFarm {
 						Bot.ArchiLogger.LogGenericInfo(Strings.CheckingOtherBadgePages);
 
 						for (byte page = 2; page <= maxPages; page++) {
-							await CheckPage(page).ConfigureAwait(false);
+							await CheckPage(page, parsedAppIDs).ConfigureAwait(false);
 						}
 					}
 
@@ -1023,7 +1030,7 @@ namespace ArchiSteamFarm {
 						for (byte page = 2; page <= maxPages; page++) {
 							// We need a copy of variable being passed when in for loops, as loop will proceed before our task is launched
 							byte currentPage = page;
-							tasks.Add(CheckPage(currentPage));
+							tasks.Add(CheckPage(currentPage, parsedAppIDs));
 						}
 					}