Use .NET 6's `ParallelForEachAsync(...)`

DiscordChatExporter.Cli/Commands/Base/ExportCommandBase.cs

@@ -14,7 +14,6 @@ using DiscordChatExporter.Core.Exceptions;
 using DiscordChatExporter.Core.Exporting;
 using DiscordChatExporter.Core.Exporting.Filtering;
 using DiscordChatExporter.Core.Exporting.Partitioning;
-using DiscordChatExporter.Core.Utils.Extensions;
 
 namespace DiscordChatExporter.Cli.Commands.Base;
 
@@ -68,13 +67,22 @@ public abstract class ExportCommandBase : TokenCommandBase
         await console.Output.WriteLineAsync($"Exporting {channels.Count} channel(s)...");
         await console.CreateProgressTicker().StartAsync(async progressContext =>
         {
-            await channels.ParallelForEachAsync(async channel =>
+            await Parallel.ForEachAsync(
+                channels,
+                new ParallelOptions
+                {
+                    MaxDegreeOfParallelism = Math.Max(1, ParallelLimit),
+                    CancellationToken = cancellationToken
+                },
+                async (channel, innerCancellationToken) =>
                 {
                     try
                     {
-                    await progressContext.StartTaskAsync($"{channel.Category.Name} / {channel.Name}", async progress =>
+                        await progressContext.StartTaskAsync(
+                            $"{channel.Category.Name} / {channel.Name}",
+                            async progress =>
                             {
-                        var guild = await Discord.GetGuildAsync(channel.GuildId, cancellationToken);
+                                var guild = await Discord.GetGuildAsync(channel.GuildId, innerCancellationToken);
 
                                 var request = new ExportRequest(
                                     guild,
@@ -90,14 +98,16 @@ public abstract class ExportCommandBase : TokenCommandBase
                                     DateFormat
                                 );
 
-                        await Exporter.ExportChannelAsync(request, progress, cancellationToken);
+                                await Exporter.ExportChannelAsync(request, progress, innerCancellationToken);
-                    });
+                            }
+                        );
                     }
                     catch (DiscordChatExporterException ex) when (!ex.IsFatal)
                     {
                         errors[channel] = ex.Message;
                     }
-            }, Math.Max(ParallelLimit, 1), cancellationToken);
+                }
+            );
         });
 
         // Print result

DiscordChatExporter.Core/Exporting/ExportRequest.cs

@@ -48,10 +48,9 @@ public partial record ExportRequest
         Snowflake? after = null,
         Snowflake? before = null)
     {
-
         // Formats path
         outputPath = Regex.Replace(outputPath, "%.", m =>
-            PathEx.EscapePath(m.Value switch
+            PathEx.EscapeFileName(m.Value switch
             {
                 "%g" => guild.Id.ToString(),
                 "%G" => guild.Name,
@@ -118,9 +117,6 @@ public partial record ExportRequest
         // File extension
         buffer.Append($".{format.GetFileExtension()}");
 
-        // Replace invalid chars
+        return PathEx.EscapeFileName(buffer.ToString());
-        PathEx.EscapePath(buffer);
-
-        return buffer.ToString();
     }
 }

DiscordChatExporter.Core/Exporting/MediaDownloader.cs

@@ -104,6 +104,6 @@ internal partial class MediaDownloader
         var fileNameWithoutExtension = Path.GetFileNameWithoutExtension(fileName);
         var fileExtension = Path.GetExtension(fileName);
 
-        return PathEx.EscapePath(fileNameWithoutExtension.Truncate(42) + '-' + urlHash + fileExtension);
+        return PathEx.EscapeFileName(fileNameWithoutExtension.Truncate(42) + '-' + urlHash + fileExtension);
     }
 }

DiscordChatExporter.Core/Utils/Extensions/AsyncExtensions.cs

@@ -1,8 +1,5 @@
-using System;
+using System.Collections.Generic;
-using System.Collections.Generic;
-using System.Linq;
 using System.Runtime.CompilerServices;
-using System.Threading;
 using System.Threading.Tasks;
 
 namespace DiscordChatExporter.Core.Utils.Extensions;
@@ -23,29 +20,4 @@ public static class AsyncExtensions
     public static ValueTaskAwaiter<IReadOnlyList<T>> GetAwaiter<T>(
         this IAsyncEnumerable<T> asyncEnumerable) =>
         asyncEnumerable.AggregateAsync().GetAwaiter();
-
-    public static async ValueTask ParallelForEachAsync<T>(
-        this IEnumerable<T> source,
-        Func<T, ValueTask> handleAsync,
-        int degreeOfParallelism,
-        CancellationToken cancellationToken = default)
-    {
-        using var semaphore = new SemaphoreSlim(degreeOfParallelism);
-
-        await Task.WhenAll(source.Select(async item =>
-        {
-            // ReSharper disable once AccessToDisposedClosure
-            await semaphore.WaitAsync(cancellationToken);
-
-            try
-            {
-                await handleAsync(item);
-            }
-            finally
-            {
-                // ReSharper disable once AccessToDisposedClosure
-                semaphore.Release();
-            }
-        }));
-    }
 }

DiscordChatExporter.Core/Utils/PathEx.cs

@@ -1,17 +1,20 @@
-using System.IO;
+using System.Collections.Generic;
+using System.IO;
 using System.Text;
 
 namespace DiscordChatExporter.Core.Utils;
 
 public static class PathEx
 {
-    public static StringBuilder EscapePath(StringBuilder pathBuffer)
+    private static readonly HashSet<char> InvalidFileNameChars = new(Path.GetInvalidFileNameChars());
+
+    public static string EscapeFileName(string path)
     {
-        foreach (var invalidChar in Path.GetInvalidFileNameChars())
+        var buffer = new StringBuilder(path.Length);
-            pathBuffer.Replace(invalidChar, '_');
 
-        return pathBuffer;
+        foreach (var c in path)
-    }
+            buffer.Append(!InvalidFileNameChars.Contains(c) ? c : '_');
 
-    public static string EscapePath(string path) => EscapePath(new StringBuilder(path)).ToString();
+        return buffer.ToString();
+    }
 }

DiscordChatExporter.Gui/ViewModels/RootViewModel.cs

@@ -210,7 +210,13 @@ public class RootViewModel : Screen
             var operations = ProgressManager.CreateOperations(dialog.Channels!.Count);
             var successfulExportCount = 0;
 
-            await dialog.Channels.Zip(operations).ParallelForEachAsync(async tuple =>
+            await Parallel.ForEachAsync(
+                dialog.Channels.Zip(operations),
+                new ParallelOptions
+                {
+                    MaxDegreeOfParallelism = Math.Max(1, _settingsService.ParallelLimit)
+                },
+                async (tuple, cancellationToken) =>
                 {
                     var (channel, operation) = tuple;
 
@@ -218,7 +224,7 @@ public class RootViewModel : Screen
                     {
                         var request = new ExportRequest(
                             dialog.Guild!,
-                        channel!,
+                            channel,
                             dialog.OutputPath!,
                             dialog.SelectedFormat,
                             dialog.After?.Pipe(Snowflake.FromDate),
@@ -230,7 +236,7 @@ public class RootViewModel : Screen
                             _settingsService.DateFormat
                         );
 
-                    await exporter.ExportChannelAsync(request, operation);
+                        await exporter.ExportChannelAsync(request, operation, cancellationToken);
 
                         Interlocked.Increment(ref successfulExportCount);
                     }
@@ -242,7 +248,8 @@ public class RootViewModel : Screen
                     {
                         operation.Dispose();
                     }
-            }, Math.Max(1, _settingsService.ParallelLimit));
+                }
+            );
 
             // Notify of overall completion
             if (successfulExportCount > 0)