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;
 
@@ -68,36 +67,47 @@ public abstract class ExportCommandBase : TokenCommandBase
         await console.Output.WriteLineAsync($"Exporting {channels.Count} channel(s)...");
         await console.CreateProgressTicker().StartAsync(async progressContext =>
         {
-            await channels.ParallelForEachAsync(async channel =>
-            {
-                try
+            await Parallel.ForEachAsync(
+                channels,
+                new ParallelOptions
+                {
+                    MaxDegreeOfParallelism = Math.Max(1, ParallelLimit),
+                    CancellationToken = cancellationToken
+                },
+                async (channel, innerCancellationToken) =>
                 {
-                    await progressContext.StartTaskAsync($"{channel.Category.Name} / {channel.Name}", async progress =>
+                    try
                     {
-                        var guild = await Discord.GetGuildAsync(channel.GuildId, cancellationToken);
-
-                        var request = new ExportRequest(
-                            guild,
-                            channel,
-                            OutputPath,
-                            ExportFormat,
-                            After,
-                            Before,
-                            PartitionLimit,
-                            MessageFilter,
-                            ShouldDownloadMedia,
-                            ShouldReuseMedia,
-                            DateFormat
+                        await progressContext.StartTaskAsync(
+                            $"{channel.Category.Name} / {channel.Name}",
+                            async progress =>
+                            {
+                                var guild = await Discord.GetGuildAsync(channel.GuildId, innerCancellationToken);
+
+                                var request = new ExportRequest(
+                                    guild,
+                                    channel,
+                                    OutputPath,
+                                    ExportFormat,
+                                    After,
+                                    Before,
+                                    PartitionLimit,
+                                    MessageFilter,
+                                    ShouldDownloadMedia,
+                                    ShouldReuseMedia,
+                                    DateFormat
+                                );
+
+                                await Exporter.ExportChannelAsync(request, progress, innerCancellationToken);
+                            }
                         );
-
-                        await Exporter.ExportChannelAsync(request, progress, cancellationToken);
-                    });
-                }
-                catch (DiscordChatExporterException ex) when (!ex.IsFatal)
-                {
-                    errors[channel] = ex.Message;
+                    }
+                    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
-        PathEx.EscapePath(buffer);
-
-        return buffer.ToString();
+        return PathEx.EscapeFileName(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.Linq;
+using System.Collections.Generic;
 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())
-            pathBuffer.Replace(invalidChar, '_');
+        var buffer = new StringBuilder(path.Length);
 
-        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

@@ -210,39 +210,46 @@ public class RootViewModel : Screen
             var operations = ProgressManager.CreateOperations(dialog.Channels!.Count);
             var successfulExportCount = 0;
 
-            await dialog.Channels.Zip(operations).ParallelForEachAsync(async tuple =>
-            {
-                var (channel, operation) = tuple;
-
-                try
-                {
-                    var request = new ExportRequest(
-                        dialog.Guild!,
-                        channel!,
-                        dialog.OutputPath!,
-                        dialog.SelectedFormat,
-                        dialog.After?.Pipe(Snowflake.FromDate),
-                        dialog.Before?.Pipe(Snowflake.FromDate),
-                        dialog.PartitionLimit,
-                        dialog.MessageFilter,
-                        dialog.ShouldDownloadMedia,
-                        _settingsService.ShouldReuseMedia,
-                        _settingsService.DateFormat
-                    );
-
-                    await exporter.ExportChannelAsync(request, operation);
-
-                    Interlocked.Increment(ref successfulExportCount);
-                }
-                catch (DiscordChatExporterException ex) when (!ex.IsFatal)
+            await Parallel.ForEachAsync(
+                dialog.Channels.Zip(operations),
+                new ParallelOptions
                 {
-                    Notifications.Enqueue(ex.Message.TrimEnd('.'));
-                }
-                finally
+                    MaxDegreeOfParallelism = Math.Max(1, _settingsService.ParallelLimit)
+                },
+                async (tuple, cancellationToken) =>
                 {
-                    operation.Dispose();
+                    var (channel, operation) = tuple;
+
+                    try
+                    {
+                        var request = new ExportRequest(
+                            dialog.Guild!,
+                            channel,
+                            dialog.OutputPath!,
+                            dialog.SelectedFormat,
+                            dialog.After?.Pipe(Snowflake.FromDate),
+                            dialog.Before?.Pipe(Snowflake.FromDate),
+                            dialog.PartitionLimit,
+                            dialog.MessageFilter,
+                            dialog.ShouldDownloadMedia,
+                            _settingsService.ShouldReuseMedia,
+                            _settingsService.DateFormat
+                        );
+
+                        await exporter.ExportChannelAsync(request, operation, cancellationToken);
+
+                        Interlocked.Increment(ref successfulExportCount);
+                    }
+                    catch (DiscordChatExporterException ex) when (!ex.IsFatal)
+                    {
+                        Notifications.Enqueue(ex.Message.TrimEnd('.'));
+                    }
+                    finally
+                    {
+                        operation.Dispose();
+                    }
                 }
-            }, Math.Max(1, _settingsService.ParallelLimit));
+            );
 
             // Notify of overall completion
             if (successfulExportCount > 0)