.NET 4.8 Framework support

Directory.Build.props

@@ -1,6 +1,6 @@
 <Project>
     <PropertyGroup>
-        <TargetFrameworks>net6.0;net7.0;net8.0</TargetFrameworks>
+        <TargetFrameworks>net48;net6.0;net7.0;net8.0</TargetFrameworks>
         <GenerateAssemblyInfo>true</GenerateAssemblyInfo>
         <Nullable>enable</Nullable>
         <NullableContextOptions>enable</NullableContextOptions>
@@ -16,4 +16,9 @@
         <GrpcPackageVersion>2.59.0</GrpcPackageVersion>
         <GrpcToolsPackageVersion>2.59.0</GrpcToolsPackageVersion>
     </PropertyGroup>
+
+		<ItemGroup Condition="'$(TargetFramework)' == 'net48'">
+			<Reference Include="System.Net.Http"/>
+			<Reference Include="System.Web"/>
+		</ItemGroup>
 </Project>

src/Directory.Build.props

@@ -1,5 +1,5 @@
 <Project>
-    <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
+    <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))"/>
     <PropertyGroup>
         <RootNamespace>EventStore.Client</RootNamespace>
     </PropertyGroup>
@@ -12,8 +12,8 @@
     </PropertyGroup>
 
     <ItemGroup Condition="$(MSBuildProjectName) != 'EventStore.Client'">
-        <ProjectReference Include="..\EventStore.Client\EventStore.Client.csproj" />
-        <Protobuf Access="internal" Include="$(ESProtoPath)" GrpcServices="Client" Link="protos/$(ESProto)" />
+        <ProjectReference Include="..\EventStore.Client\EventStore.Client.csproj"/>
+        <Protobuf Access="internal" Include="$(ESProtoPath)" GrpcServices="Client" Link="protos/$(ESProto)"/>
     </ItemGroup>
 
     <PropertyGroup>
@@ -30,8 +30,8 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <None Include="..\..\LICENSE.md" Pack="true" PackagePath="\" />
-        <None Include="..\..\ouro.png" Pack="true" PackagePath="\" />
+        <None Include="..\..\LICENSE.md" Pack="true" PackagePath="\"/>
+        <None Include="..\..\ouro.png" Pack="true" PackagePath="\"/>
     </ItemGroup>
 
     <ItemGroup>
@@ -43,11 +43,11 @@
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
         </PackageReference>
-        <PackageReference Include="MinVer" Version="3.0.0" PrivateAssets="All" />
+        <PackageReference Include="MinVer" Version="3.0.0" PrivateAssets="All"/>
     </ItemGroup>
 
     <ItemGroup>
-        <Compile Include="../EventStore.Client.Common/**/*.cs" Link="Common\%(RecursiveDir)/%(FileName)%(Extension)" />
+        <Compile Include="../EventStore.Client.Common/**/*.cs" Link="Common\%(RecursiveDir)/%(FileName)%(Extension)"/>
     </ItemGroup>
 
     <ItemGroup>

src/EventStore.Client.Common/EpochExtensions.cs

@@ -1,7 +1,23 @@
 namespace EventStore.Client;
 
 static class EpochExtensions {
+#if NET
 	static readonly DateTime UnixEpoch = DateTime.UnixEpoch;
+#else
+	const long TicksPerMillisecond = 10000;
+	const long TicksPerSecond      = TicksPerMillisecond * 1000;
+	const long TicksPerMinute      = TicksPerSecond * 60;
+	const long TicksPerHour        = TicksPerMinute * 60;
+	const long TicksPerDay         = TicksPerHour * 24;
+	const int  DaysPerYear         = 365;
+	const int  DaysPer4Years       = DaysPerYear * 4 + 1;
+	const int  DaysPer100Years     = DaysPer4Years * 25 - 1;
+	const int  DaysPer400Years     = DaysPer100Years * 4 + 1;
+	const int  DaysTo1970          = DaysPer400Years * 4 + DaysPer100Years * 3 + DaysPer4Years * 17 + DaysPerYear;
+	const long UnixEpochTicks      = DaysTo1970 * TicksPerDay;
+
+	static readonly DateTime UnixEpoch = new(UnixEpochTicks, DateTimeKind.Utc);
+#endif
 
 	public static DateTime FromTicksSinceEpoch(this long value) => new(UnixEpoch.Ticks + value, DateTimeKind.Utc);
 

src/EventStore.Client.Common/Shims/Index.cs

@@ -0,0 +1,131 @@
+#if !NET
+using System.Runtime.CompilerServices;
+
+namespace System;
+
+/// <summary>Represent a type can be used to index a collection either from the start or the end.</summary>
+/// <remarks>
+/// Index is used by the C# compiler to support the new index syntax
+/// <code>
+/// int[] someArray = new int[5] { 1, 2, 3, 4, 5 } ;
+/// int lastElement = someArray[^1]; // lastElement = 5
+/// </code>
+/// </remarks>
+internal readonly struct Index : IEquatable<Index>
+{
+    private readonly int _value;
+
+    /// <summary>Construct an Index using a value and indicating if the index is from the start or from the end.</summary>
+    /// <param name="value">The index value. it has to be zero or positive number.</param>
+    /// <param name="fromEnd">Indicating if the index is from the start or from the end.</param>
+    /// <remarks>
+    /// If the Index constructed from the end, index value 1 means pointing at the last element and index value 0 means pointing at beyond last element.
+    /// </remarks>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public Index(int value, bool fromEnd = false)
+    {
+        if (value < 0)
+        {
+            throw new ArgumentOutOfRangeException(nameof(value), "value must be non-negative");
+        }
+
+        if (fromEnd)
+            _value = ~value;
+        else
+            _value = value;
+    }
+
+    // The following private constructors mainly created for perf reason to avoid the checks
+    private Index(int value)
+    {
+        _value = value;
+    }
+
+    /// <summary>Create an Index pointing at first element.</summary>
+    public static Index Start => new Index(0);
+
+    /// <summary>Create an Index pointing at beyond last element.</summary>
+    public static Index End => new Index(~0);
+
+    /// <summary>Create an Index from the start at the position indicated by the value.</summary>
+    /// <param name="value">The index value from the start.</param>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static Index FromStart(int value)
+    {
+        if (value < 0)
+        {
+            throw new ArgumentOutOfRangeException(nameof(value), "value must be non-negative");
+        }
+
+        return new Index(value);
+    }
+
+    /// <summary>Create an Index from the end at the position indicated by the value.</summary>
+    /// <param name="value">The index value from the end.</param>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static Index FromEnd(int value)
+    {
+        if (value < 0)
+        {
+            throw new ArgumentOutOfRangeException(nameof(value), "value must be non-negative");
+        }
+
+        return new Index(~value);
+    }
+
+    /// <summary>Returns the index value.</summary>
+    public int Value
+    {
+        get
+        {
+            if (_value < 0)
+                return ~_value;
+            else
+                return _value;
+        }
+    }
+
+    /// <summary>Indicates whether the index is from the start or the end.</summary>
+    public bool IsFromEnd => _value < 0;
+
+    /// <summary>Calculate the offset from the start using the giving collection length.</summary>
+    /// <param name="length">The length of the collection that the Index will be used with. length has to be a positive value</param>
+    /// <remarks>
+    /// For performance reason, we don't validate the input length parameter and the returned offset value against negative values.
+    /// we don't validate either the returned offset is greater than the input length.
+    /// It is expected Index will be used with collections which always have non negative length/count. If the returned offset is negative and
+    /// then used to index a collection will get out of range exception which will be same affect as the validation.
+    /// </remarks>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public int GetOffset(int length)
+    {
+        int offset = _value;
+        if (IsFromEnd)
+        {
+            // offset = length - (~value)
+            // offset = length + (~(~value) + 1)
+            // offset = length + value + 1
+
+            offset += length + 1;
+        }
+        return offset;
+    }
+
+    /// <summary>Indicates whether the current Index object is equal to another object of the same type.</summary>
+    /// <param name="value">An object to compare with this object</param>
+    public override bool Equals(object? value) => value is Index && _value == ((Index)value)._value;
+
+    /// <summary>Indicates whether the current Index object is equal to another Index object.</summary>
+    /// <param name="other">An object to compare with this object</param>
+    public bool Equals(Index other) => _value == other._value;
+
+    /// <summary>Returns the hash code for this instance.</summary>
+    public override int GetHashCode() => _value;
+
+    /// <summary>Converts integer number to an Index.</summary>
+    public static implicit operator Index(int value) => FromStart(value);
+
+    /// <summary>Converts the value of the current Index object to its equivalent string representation.</summary>
+    public override string ToString() => IsFromEnd ? $"^{((uint)Value)}" : ((uint)Value).ToString();
+}
+#endif

src/EventStore.Client.Common/Shims/IsExternalInit.cs

@@ -0,0 +1,9 @@
+#if !NET
+using System.ComponentModel;
+
+// ReSharper disable once CheckNamespace
+namespace System.Runtime.CompilerServices;
+
+[EditorBrowsable(EditorBrowsableState.Never)]
+internal class IsExternalInit{}
+#endif

src/EventStore.Client.Common/Shims/Range.cs

@@ -0,0 +1,79 @@
+#if !NET
+using System.Runtime.CompilerServices;
+
+namespace System;
+
+/// <summary>Represent a range has start and end indexes.</summary>
+/// <remarks>
+/// Range is used by the C# compiler to support the range syntax.
+/// <code>
+/// int[] someArray = new int[5] { 1, 2, 3, 4, 5 };
+/// int[] subArray1 = someArray[0..2]; // { 1, 2 }
+/// int[] subArray2 = someArray[1..^0]; // { 2, 3, 4, 5 }
+/// </code>
+/// </remarks>
+internal readonly struct Range : IEquatable<Range>
+{
+    /// <summary>Represent the inclusive start index of the Range.</summary>
+    public Index Start { get; }
+
+    /// <summary>Represent the exclusive end index of the Range.</summary>
+    public Index End { get; }
+
+    /// <summary>Construct a Range object using the start and end indexes.</summary>
+    /// <param name="start">Represent the inclusive start index of the range.</param>
+    /// <param name="end">Represent the exclusive end index of the range.</param>
+    public Range(Index start, Index end)
+    {
+        Start = start;
+        End = end;
+    }
+
+    /// <summary>Indicates whether the current Range object is equal to another object of the same type.</summary>
+    /// <param name="value">An object to compare with this object</param>
+    public override bool Equals(object? value) =>
+        value is Range r &&
+        r.Start.Equals(Start) &&
+        r.End.Equals(End);
+
+    /// <summary>Indicates whether the current Range object is equal to another Range object.</summary>
+    /// <param name="other">An object to compare with this object</param>
+    public bool Equals(Range other) => other.Start.Equals(Start) && other.End.Equals(End);
+
+    /// <summary>Returns the hash code for this instance.</summary>
+    public override int GetHashCode() => Start.GetHashCode() * 31 + End.GetHashCode();
+
+    /// <summary>Converts the value of the current Range object to its equivalent string representation.</summary>
+    public override string ToString() => $"{Start}..{End}";
+
+    /// <summary>Create a Range object starting from start index to the end of the collection.</summary>
+    public static Range StartAt(Index start) => new(start, Index.End);
+
+    /// <summary>Create a Range object starting from first element in the collection to the end Index.</summary>
+    public static Range EndAt(Index end) => new(Index.Start, end);
+
+    /// <summary>Create a Range object starting from first element to the end.</summary>
+    public static Range All => new(Index.Start, Index.End);
+
+    /// <summary>Calculate the start offset and length of range object using a collection length.</summary>
+    /// <param name="length">The length of the collection that the range will be used with. length has to be a positive value.</param>
+    /// <remarks>
+    /// For performance reason, we don't validate the input length parameter against negative values.
+    /// It is expected Range will be used with collections which always have non negative length/count.
+    /// We validate the range is inside the length scope though.
+    /// </remarks>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public (int Offset, int Length) GetOffsetAndLength(int length)
+    {
+        int start = Start.GetOffset(length);
+        int end = End.GetOffset(length);
+
+        if ((uint)end > (uint)length || (uint)start > (uint)end)
+        {
+            throw new ArgumentOutOfRangeException(nameof(length));
+        }
+
+        return (start, end - start);
+    }
+}
+#endif

src/EventStore.Client.Common/Shims/TaskCompletionSource.cs

@@ -0,0 +1,8 @@
+#if !NET
+namespace System.Threading.Tasks;
+
+internal class TaskCompletionSource : TaskCompletionSource<object?> {
+    public void SetResult() => base.SetResult(null);
+    public bool TrySetResult() => base.TrySetResult(null);
+}
+#endif

src/EventStore.Client.Operations/EventStore.Client.Operations.csproj

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project Sdk="Microsoft.NET.Sdk">
-	<PropertyGroup>
-		<Description>The GRPC client API for Event Store Operations, e.g., Scavenging. Get the open source or commercial versions of Event Store server from https://eventstore.com/</Description>
-	</PropertyGroup>
+    <PropertyGroup>
+        <Description>The GRPC client API for Event Store Operations, e.g., Scavenging. Get the open source or commercial versions of Event Store server from https://eventstore.com/</Description>
+    </PropertyGroup>
 </Project>

src/EventStore.Client.PersistentSubscriptions/EventStore.Client.PersistentSubscriptions.csproj

@@ -1,6 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project Sdk="Microsoft.NET.Sdk">
-	<PropertyGroup>
-		<Description>The GRPC client API for Event Store Persistent Subscriptions. Get the open source or commercial versions of Event Store server from https://eventstore.com/</Description>
-	</PropertyGroup>
+    <PropertyGroup>
+        <Description>The GRPC client API for Event Store Persistent Subscriptions. Get the open source or commercial versions of Event Store server from https://eventstore.com/</Description>
+    </PropertyGroup>
+    <ItemGroup>
+        <InternalsVisibleTo Include="EventStore.Client.PersistentSubscriptions.Tests"/>
+    </ItemGroup>
 </Project>