SepReader: Add async support (C# 13+ only) (#219)

Fix #27
nietras · Jan 19, 2025 · f92b65b · f92b65b
1 parent c2e7cd9
commit f92b65b
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Showing 14 changed files with 1,696 additions and 716 deletions.
diff --git a/.editorconfig b/.editorconfig
@@ -288,7 +288,7 @@ dotnet_diagnostic.CA1851.severity = warning
 dotnet_diagnostic.CA1834.severity = warning
 
 # CA2007: Do not directly await a Task
-dotnet_diagnostic.CA2007.severity = warning
+dotnet_diagnostic.CA2007.severity = none
 
 # CA2008: Do not create tasks without passing a TaskScheduler
 dotnet_diagnostic.CA2008.severity = warning

diff --git a/README.md b/README.md
@@ -1916,17 +1916,25 @@ namespace nietras.SeparatedValues
         public static char Separator { get; }
     }
     [System.Diagnostics.DebuggerDisplay("{DebuggerDisplay,nq}")]
-    public sealed class SepReader : nietras.SeparatedValues.SepReaderState, System.Collections.Generic.IEnumerable<nietras.SeparatedValues.SepReader.Row>, System.Collections.Generic.IEnumerator<nietras.SeparatedValues.SepReader.Row>, System.Collections.IEnumerable, System.Collections.IEnumerator, System.IDisposable
+    public sealed class SepReader : nietras.SeparatedValues.SepReaderState, System.Collections.Generic.IAsyncEnumerable<nietras.SeparatedValues.SepReader.Row>, System.Collections.Generic.IEnumerable<nietras.SeparatedValues.SepReader.Row>, System.Collections.Generic.IEnumerator<nietras.SeparatedValues.SepReader.Row>, System.Collections.IEnumerable, System.Collections.IEnumerator, System.IDisposable
     {
         public nietras.SeparatedValues.SepReader.Row Current { get; }
         public bool HasHeader { get; }
         public bool HasRows { get; }
         public nietras.SeparatedValues.SepReaderHeader Header { get; }
         public bool IsEmpty { get; }
         public nietras.SeparatedValues.SepSpec Spec { get; }
+        public nietras.SeparatedValues.SepReader.AsyncEnumerator GetAsyncEnumerator(System.Threading.CancellationToken cancellationToken = default) { }
         public nietras.SeparatedValues.SepReader GetEnumerator() { }
         public bool MoveNext() { }
+        public System.Threading.Tasks.ValueTask<bool> MoveNextAsync(System.Threading.CancellationToken cancellationToken = default) { }
         public string ToString(int index) { }
+        public readonly struct AsyncEnumerator : System.Collections.Generic.IAsyncEnumerator<nietras.SeparatedValues.SepReader.Row>, System.IAsyncDisposable
+        {
+            public nietras.SeparatedValues.SepReader.Row Current { get; }
+            public System.Threading.Tasks.ValueTask DisposeAsync() { }
+            public System.Threading.Tasks.ValueTask<bool> MoveNextAsync() { }
+        }
         [System.Diagnostics.DebuggerDisplay("{DebuggerDisplay}")]
         [System.Obsolete(("Types with embedded references are not supported in this version of your compiler" +
             "."), true)]
@@ -2008,8 +2016,15 @@ namespace nietras.SeparatedValues
         public static nietras.SeparatedValues.SepReader From(in this nietras.SeparatedValues.SepReaderOptions options, System.IO.TextReader reader) { }
         public static nietras.SeparatedValues.SepReader From(in this nietras.SeparatedValues.SepReaderOptions options, string name, System.Func<string, System.IO.Stream> nameToStream) { }
         public static nietras.SeparatedValues.SepReader From(in this nietras.SeparatedValues.SepReaderOptions options, string name, System.Func<string, System.IO.TextReader> nameToReader) { }
+        public static System.Threading.Tasks.ValueTask<nietras.SeparatedValues.SepReader> FromAsync(this nietras.SeparatedValues.SepReaderOptions options, byte[] buffer, System.Threading.CancellationToken cancellationToken = default) { }
+        public static System.Threading.Tasks.ValueTask<nietras.SeparatedValues.SepReader> FromAsync(this nietras.SeparatedValues.SepReaderOptions options, System.IO.Stream stream, System.Threading.CancellationToken cancellationToken = default) { }
+        public static System.Threading.Tasks.ValueTask<nietras.SeparatedValues.SepReader> FromAsync(this nietras.SeparatedValues.SepReaderOptions options, System.IO.TextReader reader, System.Threading.CancellationToken cancellationToken = default) { }
+        public static System.Threading.Tasks.ValueTask<nietras.SeparatedValues.SepReader> FromAsync(this nietras.SeparatedValues.SepReaderOptions options, string name, System.Func<string, System.IO.Stream> nameToStream, System.Threading.CancellationToken cancellationToken = default) { }
+        public static System.Threading.Tasks.ValueTask<nietras.SeparatedValues.SepReader> FromAsync(this nietras.SeparatedValues.SepReaderOptions options, string name, System.Func<string, System.IO.TextReader> nameToReader, System.Threading.CancellationToken cancellationToken = default) { }
         public static nietras.SeparatedValues.SepReader FromFile(in this nietras.SeparatedValues.SepReaderOptions options, string filePath) { }
+        public static System.Threading.Tasks.ValueTask<nietras.SeparatedValues.SepReader> FromFileAsync(this nietras.SeparatedValues.SepReaderOptions options, string filePath, System.Threading.CancellationToken cancellationToken = default) { }
         public static nietras.SeparatedValues.SepReader FromText(in this nietras.SeparatedValues.SepReaderOptions options, string text) { }
+        public static System.Threading.Tasks.ValueTask<nietras.SeparatedValues.SepReader> FromTextAsync(this nietras.SeparatedValues.SepReaderOptions options, string text, System.Threading.CancellationToken cancellationToken = default) { }
         public static System.Collections.Generic.IEnumerable<T> ParallelEnumerate<T>(this nietras.SeparatedValues.SepReader reader, nietras.SeparatedValues.SepReader.RowFunc<T> select) { }
         public static System.Collections.Generic.IEnumerable<T> ParallelEnumerate<T>(this nietras.SeparatedValues.SepReader reader, nietras.SeparatedValues.SepReader.RowTryFunc<T> trySelect) { }
         public static System.Collections.Generic.IEnumerable<T> ParallelEnumerate<T>(this nietras.SeparatedValues.SepReader reader, nietras.SeparatedValues.SepReader.RowFunc<T> select, int degreeOfParallism) { }

diff --git a/src/Sep.ComparisonBenchmarks/PackageAssetsBench.cs b/src/Sep.ComparisonBenchmarks/PackageAssetsBench.cs
@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using System.Threading.Tasks;
 using BenchmarkDotNet.Attributes;
 using BenchmarkDotNet.Configs;
 using CsvHelper;
@@ -78,6 +79,14 @@ public void Sep______()
         foreach (var row in reader) { }
     }
 
+    [Benchmark]
+    public async ValueTask Sep_Async()
+    {
+        using var reader = await Sep.Reader(o => o with { HasHeader = false })
+                                    .FromAsync(Reader.CreateReader());
+        await foreach (var row in reader) { }
+    }
+
     [Benchmark]
     public void Sep_Unescape()
     {

diff --git a/src/Sep.Test/PackageAssetsTest.cs b/src/Sep.Test/PackageAssetsTest.cs
@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 namespace nietras.SeparatedValues.Test;
@@ -35,6 +36,23 @@ public class PackageAssetsTest
     public void PackageAssetsTest_Read_WithQuotes_Unescape(SepCreateToString createToString) => VerifyRead(WithQuotes, createToString, unescape: true);
 
 
+    [DataTestMethod]
+    [DynamicData(nameof(ToStrings))]
+    public async ValueTask PackageAssetsTest_Read_NoQuotes_Async(SepCreateToString createToString) => await VerifyReadAsync(NoQuotes, createToString);
+
+    [DataTestMethod]
+    [DynamicData(nameof(ToStrings))]
+    public async ValueTask PackageAssetsTest_Read_NoQuotes_Unescape_Async(SepCreateToString createToString) => await VerifyReadAsync(NoQuotes, createToString, unescape: true);
+
+    [DataTestMethod]
+    [DynamicData(nameof(ToStrings))]
+    public async ValueTask PackageAssetsTest_Read_WithQuotes_Async(SepCreateToString createToString) => await VerifyReadAsync(WithQuotes, createToString);
+
+    [DataTestMethod]
+    [DynamicData(nameof(ToStrings))]
+    public async ValueTask PackageAssetsTest_Read_WithQuotes_Unescape_Async(SepCreateToString createToString) => await VerifyReadAsync(WithQuotes, createToString, unescape: true);
+
+
     [DataTestMethod]
     [DynamicData(nameof(ToStrings))]
     public void PackageAssetsTest_Enumerate_NoQuotes(SepCreateToString createToString) =>
@@ -184,15 +202,35 @@ static void VerifyRead(string text, SepCreateToString createToString, bool unesc
         var rowIndex = 0;
         foreach (var row in reader)
         {
-            var expectedCols = expected[rowIndex];
-            expectedCols = unescape ? UnescapeColsByTrim(expectedCols) : expectedCols;
-            Assert.AreEqual(expectedCols.Length, row.ColCount);
-            CollectionAssert.AreEqual(expectedCols, row[..].ToStringsArray());
+            AssertCols(row, rowIndex, unescape, expected);
             ++rowIndex;
         }
         Assert.AreEqual(expected.Count, rowIndex);
     }
 
+    static async ValueTask VerifyReadAsync(string text, SepCreateToString createToString, bool unescape = false)
+    {
+        var expected = ReadLineSplitAsList(text);
+        using var reader = await Sep
+            .Reader(o => o with { HasHeader = false, CreateToString = createToString, Unescape = unescape })
+            .FromTextAsync(text);
+        var rowIndex = 0;
+        await foreach (var row in reader)
+        {
+            AssertCols(row, rowIndex, unescape, expected);
+            ++rowIndex;
+        }
+        Assert.AreEqual(expected.Count, rowIndex);
+    }
+
+    static void AssertCols(SepReader.Row row, int rowIndex, bool unescape, List<string[]> expected)
+    {
+        var expectedCols = expected[rowIndex];
+        expectedCols = unescape ? UnescapeColsByTrim(expectedCols) : expectedCols;
+        Assert.AreEqual(expectedCols.Length, row.ColCount);
+        CollectionAssert.AreEqual(expectedCols, row[..].ToStringsArray());
+    }
+
     static void VerifyEnumerate(string text, SepCreateToString createToString,
         Func<SepReader, SepReader.RowFunc<string[]>, IEnumerable<string[]>> enumerate,
         bool unescape = false)

diff --git a/src/Sep.Test/SepReaderNoHeaderTest.cs b/src/Sep.Test/SepReaderNoHeaderTest.cs