From 0b1ddd39d500c39103d7fc68d23e62b74067242b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Domeradzki?= <JustArchi@JustArchi.net>
Date: Sun, 30 Mar 2025 21:06:33 +0200
Subject: [PATCH] Optimize serializable file writes

---
 .../Collections/ConcurrentHashSet.cs          | 81 ++++++++++++-------
 ArchiSteamFarm/Collections/ConcurrentList.cs  | 19 ++++-
 .../ObservableConcurrentDictionary.cs         |  2 +
 ArchiSteamFarm/Helpers/SerializableFile.cs    | 12 ---
 4 files changed, 73 insertions(+), 41 deletions(-)

diff --git a/ArchiSteamFarm/Collections/ConcurrentHashSet.cs b/ArchiSteamFarm/Collections/ConcurrentHashSet.cs
index cadce40d4..232d59b0c 100644
--- a/ArchiSteamFarm/Collections/ConcurrentHashSet.cs
+++ b/ArchiSteamFarm/Collections/ConcurrentHashSet.cs
@@ -100,9 +100,7 @@ public sealed class ConcurrentHashSet<T> : IReadOnlySet<T>, ISet<T> where T : no
 	public void ExceptWith(IEnumerable<T> other) {
 		ArgumentNullException.ThrowIfNull(other);
 
-		foreach (T item in other) {
-			Remove(item);
-		}
+		RemoveRange(other);
 	}
 
 	[MustDisposeResource]
@@ -113,8 +111,14 @@ public sealed class ConcurrentHashSet<T> : IReadOnlySet<T>, ISet<T> where T : no
 
 		IReadOnlySet<T> otherSet = other as IReadOnlySet<T> ?? other.ToHashSet();
 
-		foreach (T item in this.Where(item => !otherSet.Contains(item))) {
-			Remove(item);
+		bool modified = false;
+
+		foreach (T _ in this.Where(item => !otherSet.Contains(item) && BackingCollection.TryRemove(item, out _))) {
+			modified = true;
+		}
+
+		if (modified) {
+			OnModified?.Invoke(this, EventArgs.Empty);
 		}
 	}
 
@@ -182,24 +186,24 @@ public sealed class ConcurrentHashSet<T> : IReadOnlySet<T>, ISet<T> where T : no
 		ArgumentNullException.ThrowIfNull(other);
 
 		IReadOnlySet<T> otherSet = other as IReadOnlySet<T> ?? other.ToHashSet();
-		HashSet<T> removed = [];
 
-		foreach (T item in otherSet.Where(Contains)) {
-			removed.Add(item);
-			Remove(item);
+		HashSet<T> removed = otherSet.Where(item => Contains(item) && BackingCollection.TryRemove(item, out _)).ToHashSet();
+
+		bool modified = removed.Count > 0;
+
+		foreach (T _ in otherSet.Where(item => !removed.Contains(item) && BackingCollection.TryAdd(item, true))) {
+			modified = true;
 		}
 
-		foreach (T item in otherSet.Where(item => !removed.Contains(item))) {
-			Add(item);
+		if (modified) {
+			OnModified?.Invoke(this, EventArgs.Empty);
 		}
 	}
 
 	public void UnionWith(IEnumerable<T> other) {
 		ArgumentNullException.ThrowIfNull(other);
 
-		foreach (T otherElement in other) {
-			Add(otherElement);
-		}
+		AddRange(other);
 	}
 
 	void ICollection<T>.Add(T item) {
@@ -215,44 +219,66 @@ public sealed class ConcurrentHashSet<T> : IReadOnlySet<T>, ISet<T> where T : no
 	public bool AddRange(IEnumerable<T> items) {
 		ArgumentNullException.ThrowIfNull(items);
 
-		bool result = false;
+		bool modified = false;
 
-		foreach (T _ in items.Where(Add)) {
-			result = true;
+		foreach (T _ in items.Where(item => BackingCollection.TryAdd(item, true))) {
+			modified = true;
 		}
 
-		return result;
+		if (modified) {
+			OnModified?.Invoke(this, EventArgs.Empty);
+		}
+
+		return modified;
 	}
 
 	[PublicAPI]
 	public bool RemoveRange(IEnumerable<T> items) {
 		ArgumentNullException.ThrowIfNull(items);
 
-		bool result = false;
+		bool modified = false;
 
-		foreach (T _ in items.Where(Remove)) {
-			result = true;
+		foreach (T _ in items.Where(item => BackingCollection.TryRemove(item, out _))) {
+			modified = true;
 		}
 
-		return result;
+		if (modified) {
+			OnModified?.Invoke(this, EventArgs.Empty);
+		}
+
+		return modified;
 	}
 
 	[PublicAPI]
 	public int RemoveWhere(Predicate<T> match) {
 		ArgumentNullException.ThrowIfNull(match);
 
-		return BackingCollection.Keys.Where(match.Invoke).Count(key => BackingCollection.TryRemove(key, out _));
+		int count = BackingCollection.Keys.Where(match.Invoke).Count(key => BackingCollection.TryRemove(key, out _));
+
+		if (count > 0) {
+			OnModified?.Invoke(this, EventArgs.Empty);
+		}
+
+		return count;
 	}
 
 	[PublicAPI]
-	public bool ReplaceIfNeededWith(IReadOnlyCollection<T> other) {
+	public bool ReplaceIfNeededWith(IEnumerable<T> other) {
 		ArgumentNullException.ThrowIfNull(other);
 
-		if (SetEquals(other)) {
+		ICollection<T> otherCollection = other as ICollection<T> ?? other.ToHashSet();
+
+		if (SetEquals(otherCollection)) {
 			return false;
 		}
 
-		ReplaceWith(other);
+		BackingCollection.Clear();
+
+		foreach (T item in otherCollection) {
+			BackingCollection.TryAdd(item, true);
+		}
+
+		OnModified?.Invoke(this, EventArgs.Empty);
 
 		return true;
 	}
@@ -261,7 +287,6 @@ public sealed class ConcurrentHashSet<T> : IReadOnlySet<T>, ISet<T> where T : no
 	public void ReplaceWith(IEnumerable<T> other) {
 		ArgumentNullException.ThrowIfNull(other);
 
-		Clear();
-		UnionWith(other);
+		ReplaceIfNeededWith(other);
 	}
 }
diff --git a/ArchiSteamFarm/Collections/ConcurrentList.cs b/ArchiSteamFarm/Collections/ConcurrentList.cs
index a25b70afd..d83667540 100644
--- a/ArchiSteamFarm/Collections/ConcurrentList.cs
+++ b/ArchiSteamFarm/Collections/ConcurrentList.cs
@@ -24,6 +24,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.Json.Serialization;
 using JetBrains.Annotations;
 using Nito.AsyncEx;
@@ -60,6 +61,12 @@ public sealed class ConcurrentList<T> : IList<T>, IReadOnlyList<T> {
 			ArgumentOutOfRangeException.ThrowIfNegative(index);
 
 			using (Lock.WriterLock()) {
+				T oldValue = BackingCollection[index];
+
+				if (EqualityComparer<T>.Default.Equals(oldValue, value)) {
+					return;
+				}
+
 				BackingCollection[index] = value;
 			}
 
@@ -86,6 +93,10 @@ public sealed class ConcurrentList<T> : IList<T>, IReadOnlyList<T> {
 
 	public void Clear() {
 		using (Lock.WriterLock()) {
+			if (BackingCollection.Count == 0) {
+				return;
+			}
+
 			BackingCollection.Clear();
 		}
 
@@ -155,9 +166,15 @@ public sealed class ConcurrentList<T> : IList<T>, IReadOnlyList<T> {
 	public void ReplaceWith(IEnumerable<T> collection) {
 		ArgumentNullException.ThrowIfNull(collection);
 
+		ICollection<T> newCollection = collection as ICollection<T> ?? collection.ToList();
+
 		using (Lock.WriterLock()) {
+			if (BackingCollection.SequenceEqual(newCollection)) {
+				return;
+			}
+
 			BackingCollection.Clear();
-			BackingCollection.AddRange(collection);
+			BackingCollection.AddRange(newCollection);
 		}
 
 		OnModified?.Invoke(this, EventArgs.Empty);
diff --git a/ArchiSteamFarm/Collections/ObservableConcurrentDictionary.cs b/ArchiSteamFarm/Collections/ObservableConcurrentDictionary.cs
index 2feef2d3b..c0e83ee51 100644
--- a/ArchiSteamFarm/Collections/ObservableConcurrentDictionary.cs
+++ b/ArchiSteamFarm/Collections/ObservableConcurrentDictionary.cs
@@ -65,6 +65,7 @@ public sealed class ObservableConcurrentDictionary<TKey, TValue> : IDictionary<T
 			}
 
 			BackingDictionary[key] = value;
+
 			OnModified?.Invoke(this, EventArgs.Empty);
 		}
 	}
@@ -111,6 +112,7 @@ public sealed class ObservableConcurrentDictionary<TKey, TValue> : IDictionary<T
 		}
 
 		BackingDictionary.Clear();
+
 		OnModified?.Invoke(this, EventArgs.Empty);
 	}
 
diff --git a/ArchiSteamFarm/Helpers/SerializableFile.cs b/ArchiSteamFarm/Helpers/SerializableFile.cs
index 6f8e3a4c2..62a32b2d8 100644
--- a/ArchiSteamFarm/Helpers/SerializableFile.cs
+++ b/ArchiSteamFarm/Helpers/SerializableFile.cs
@@ -105,12 +105,6 @@ public abstract class SerializableFile : IDisposable {
 			string newFilePath = $"{serializableFile.FilePath}.new";
 
 			if (File.Exists(serializableFile.FilePath)) {
-				string currentJson = await File.ReadAllTextAsync(serializableFile.FilePath).ConfigureAwait(false);
-
-				if (json == currentJson) {
-					return;
-				}
-
 				await File.WriteAllTextAsync(newFilePath, json).ConfigureAwait(false);
 
 				File.Replace(newFilePath, serializableFile.FilePath, null);
@@ -156,12 +150,6 @@ public abstract class SerializableFile : IDisposable {
 			// We always want to write entire content to temporary file first, in order to never load corrupted data, also when target file doesn't exist
 #pragma warning disable CA3003 // Ignored due to caller's intent
 			if (File.Exists(filePath)) {
-				string currentJson = await File.ReadAllTextAsync(filePath).ConfigureAwait(false);
-
-				if (json == currentJson) {
-					return true;
-				}
-
 				await File.WriteAllTextAsync(newFilePath, json).ConfigureAwait(false);
 
 				File.Replace(newFilePath, filePath, null);