Add Base64Url support for netstandard 2.0

[buyaa-n]

Add Base64Url package that supports netstandard 2.0 and .NET framework

Pretty much same implementation excluding the parts that not supported in netstandard like:

• No vectorization, though the serial part of the implementation kept as is
• No static abstract interface, therefore, no code sharing between Span, Span overloads
• No Span.IndexOfAnyExcept(SearchValues) support so validation APIs logic differs around that are, but main logic is same
• No Math.DivRem available

Fixes #1658

[dotnet-issue-labeler]

Note regarding the new-api-needs-documentation label:

This serves as a reminder for when your PR is modifying a ref *.cs file and adding/modifying public APIs, please make sure the API implementation in the src *.cs file is documented with triple slash comments, so the PR reviewers can sign off that change.

[dotnet-issue-labeler]

Note regarding the new-api-needs-documentation label:

This serves as a reminder for when your PR is modifying a ref *.cs file and adding/modifying public APIs, please make sure the API implementation in the src *.cs file is documented with triple slash comments, so the PR reviewers can sign off that change.

[ViktorHofer]

@buyaa-n I tried my feedback out in a code space. Here's the patch that you can directly apply:

From 2b35645c7eee21dfdbdd35855d709c9def195097 Mon Sep 17 00:00:00 2001
From: Viktor Hofer <viktor.hofer@microsoft.com>
Date: Tue, 18 Jun 2024 16:17:54 +0000
Subject: [PATCH] Enable compiler doc generation and simplify forwards

---
 .../src/Microsoft.Bcl.Memory.csproj                  | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/libraries/Microsoft.Bcl.Memory/src/Microsoft.Bcl.Memory.csproj b/src/libraries/Microsoft.Bcl.Memory/src/Microsoft.Bcl.Memory.csproj
index aac0fba3d95..fa7bc6e2c33 100644
--- a/src/libraries/Microsoft.Bcl.Memory/src/Microsoft.Bcl.Memory.csproj
+++ b/src/libraries/Microsoft.Bcl.Memory/src/Microsoft.Bcl.Memory.csproj
@@ -3,7 +3,6 @@
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;$(NetFrameworkMinimum);$(NetCoreAppCurrent)</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>
     <IsPackable>true</IsPackable>
     <!-- Disabling baseline validation since this is a brand new package.
          Once this package has shipped a stable version, the following line
@@ -19,17 +18,20 @@
 
   <!-- DesignTimeBuild requires all the TargetFramework Derived Properties to not be present in the first property group. -->
   <PropertyGroup>
-    <IsPartialFacadeAssembly Condition="$([MSBuild]::GetTargetFrameworkIdentifier('$(TargetFramework)')) == '.NETCoreApp'">true</IsPartialFacadeAssembly>
-    <OmitResources Condition="'$(IsPartialFacadeAssembly)' == 'true'">true</OmitResources>
+    <OmitResources Condition="$([MSBuild]::GetTargetFrameworkIdentifier('$(TargetFramework)')) == '.NETCoreApp'">true</OmitResources>
   </PropertyGroup>
 
-  <ItemGroup Condition="'$(IsPartialFacadeAssembly)' != 'true'">
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'">
+    <Compile Include="..\ref\Microsoft.Bcl.Memory.Forwards.cs" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
     <Compile Include="System\Buffers\Text\Base64UrlDecoder.cs" />
     <Compile Include="System\Buffers\Text\Base64UrlEncoder.cs" />
     <Compile Include="System\Buffers\Text\Base64UrlValidator.cs" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(IsPartialFacadeAssembly)' != 'true'">
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
     <PackageReference Include="System.Memory" Version="$(SystemMemoryVersion)" />
   </ItemGroup>

[ViktorHofer]

The allconfigurations leg is failing because the netstandard2.0 version of Base64Url has the ClsCompliant(false) attribute on it but the net9.0 version doesn't. If that's intentional, create a suppression file. The error explains how to do that (./dotnet.sh pack src/libraries/Microsoft.Bcl.Memory/src/Microsoft.Bcl.Memory.csproj /p:ApiCompatGenerateSuppressionFile=true).

[buyaa-n]

@buyaa-n I tried my feedback out in a code space. Here's the patch that you can directly apply:

Thanks @ViktorHofer, couldn't you apply the patch yourself? I am not really sure how to apply the patch

[ViktorHofer]

No, I don't have write permissions to your fork. You can either enable perms or apply the patch yourself (if git apply ... doesn't work, feel free to manually update the file).

[buyaa-n]

No, I don't have write permissions to your fork. You can either enable perms

For the PR Allow edits and access to secrets by maintainers checkbox is checked, I will try to enable perms on my fork

apply the patch yourself (if git apply ... doesn't work, feel free to manually update the file).

I tried that and error: corrupt patch at line 45, I did not change/add anything, I guess it is from Linux/windows line endings

[buyaa-n]

No, I don't have write permissions to your fork. You can either enable perms

@ViktorHofer I added you as collaborator, please accept and apply your patch

[ViktorHofer]

The removal of the ClsCompliant(false) attribute is non-breaking, right? I'm 99% sure it isn't but just want to double check.

[buyaa-n]

The removal of the ClsCompliant(false) attribute is non-breaking, right? I'm 99% sure it isn't but just want to double check.

Weird there were ClsCompliant warning on uint ushort types that is why I added the attribute, but somehow now I don't see the warning when removing the attribute, now removed the attribute and suppression

[stephentoub]

With the exception of the code in these ifdefs, and with calls being prefixed with decoder., this whole file is an exact copy of what was in the other file, right? Or are there other changes?

[buyaa-n]

Exactly as you said,, only changes are if-defs for netsandard, and type parameter to decoder no new changes. Well, there is small bugfix that related to the new tests added, nothing else new

Basically all internal members from Base64Decoder and Base64Encoder moved in this Base64Herlper type to avoid conflict referencing Base64 from netstandard project between .NET 9 and netstandard versions.

[stephentoub]

Well, there is small bugfix that related to the new tests added, nothing else new

What is that fix?

[buyaa-n]

I was fixed the bug found with Base64Url fuzzing only for byte overloads, the same bug left for char overloads.

The diff is here 73acb51