[Rgen] Implement the generation of the smart enums. (#21562)

Add the code generation for smart enumerators. This means the following
changes:

1. Refactor the way we register the diff pipelines.
2. Add code that generates the Extension class for the enums.
3. Add code that will generate the Library.g.cs partial class.

---------

Co-authored-by: Rolf Bjarne Kvinge <[email protected]>

src/Makefile

@@ -459,6 +459,8 @@ $($(2)_DOTNET_BUILD_DIR)/$(4)/Microsoft.$(1)%dll $($(2)_DOTNET_BUILD_DIR)/$(4)/M
 		$(DOTNET_FLAGS) \
 		/analyzer:$(ROSLYN_GENERATOR_COMMON) \
 		/analyzer:$(ROSLYN_GENERATOR) \
+		/generatedfilesout:$($(2)_DOTNET_BUILD_DIR)/generated-sources \
+		/reportanalyzer:$(ROSLYN_GENERATOR) \
 		-unsafe \
 		-optimize \
 		$$(ARGS_$(1)) \

src/ObjCBindings/FieldAttribute.cs

@@ -10,7 +10,22 @@ namespace ObjCBindings {
 	/// </summary>
 	[Experimental ("APL0003")]
 	[AttributeUsage (AttributeTargets.Property | AttributeTargets.Field)]
-	public sealed class FieldAttribute<T> : Attribute where T : FieldTag {
+	public class FieldAttribute<T> : Attribute where T : Enum {
+
+		/// <summary>
+		/// Extra configuration flags for the field.
+		/// </summary>
+		public T? Flags { get; set; } = default;
+
+		/// <summary>
+		/// Get/Set the native symbol represented by the attribute.
+		/// </summary>
+		public string SymbolName { get; set; }
+
+		/// <summary>
+		/// Get/Set the library that contains the symbol.
+		/// </summary>
+		public string? LibraryName { get; set; } = default;
 
 		/// <summary>
 		/// Create a new FieldAttribute for the given symbol and using the namespace as its containing library.
@@ -19,6 +34,8 @@ public sealed class FieldAttribute<T> : Attribute where T : FieldTag {
 		public FieldAttribute (string symbolName)
 		{
 			SymbolName = symbolName;
+			Flags = default (T);
+			LibraryName = null;
 		}
 
 		/// <summary>
@@ -30,17 +47,33 @@ public FieldAttribute (string symbolName, string libraryName)
 		{
 			SymbolName = symbolName;
 			LibraryName = libraryName;
+			Flags = default (T);
 		}
 
-
 		/// <summary>
-		/// Get/Set the symbol represented by the attribute.
+		/// Create a new FieldAttribute for the given symbol and customizing the flags.
+		/// <param name="symbolName">The name of the symbol.</param>
+		/// <param name="flags">The flags to customize the field.</param>
 		/// </summary>
-		public string SymbolName { get; set; }
+		public FieldAttribute (string symbolName, T? flags)
+		{
+			SymbolName = symbolName;
+			Flags = flags;
+			LibraryName = null;
+		}
 
 		/// <summary>
-		/// Get/Set the library that contains the symbol..
+		/// Create a new FieldAttribute for the given symbol in the provided library and customizing the flags.
+		/// <param name="symbolName">The name of the symbol.</param>
+		/// <param name="libraryName">The name of the library that contains the symbol.</param>
+		/// <param name="flags">The flags to customize the field.</param>
 		/// </summary>
-		public string? LibraryName { get; set; }
+		public FieldAttribute (string symbolName, string libraryName, T? flags)
+		{
+			SymbolName = symbolName;
+			LibraryName = libraryName;
+			Flags = flags;
+		}
+
 	}
 }

src/ObjCBindings/FieldTag.cs

@@ -6,15 +6,26 @@
 namespace ObjCBindings {
 
 	/// <summary>
-	/// Base class use to flag a FieldAttribute usage. Each FieldAttribute must have a flag attached to it so that the 
-	/// binding generator analyzer can verify the binding definition.
+	/// The exported constant/field is a class/interface property field.
 	/// </summary>
+	[Flags]
 	[Experimental ("APL0003")]
-	public abstract class FieldTag { }
+	public enum Field {
+		/// <summary>
+		/// Use the default values.
+		/// </summary>
+		None = 0,
+	}
 
 	/// <summary>
 	/// Field flag that states that the field is used as a Enum value.
 	/// </summary>
+	[Flags]
 	[Experimental ("APL0003")]
-	public sealed class EnumValue : FieldTag { }
+	public enum EnumValue {
+		/// <summary>
+		/// Use the default values.
+		/// </summary>
+		None = 0,
+	}
 }

src/rgen/Microsoft.Macios.Binding.Common/Microsoft.Macios.Binding.Common.csproj

@@ -22,6 +22,9 @@
         <Compile Include="..\..\bgen\PlatformName.cs" >
             <Link>external\PlatformName.cs</Link>
         </Compile>
+        <Compile Include="..\..\ObjCBindings\FieldTag.cs">
+            <Link>external\FieldTag.cs</Link>
+        </Compile>
     </ItemGroup>
 
 </Project>

src/rgen/Microsoft.Macios.Bindings.Analyzer/BindingTypeSemanticAnalyzer.cs

@@ -24,7 +24,7 @@ public class BindingTypeSemanticAnalyzer : DiagnosticAnalyzer {
 			typeof (Resources));
 	const string Category = "Usage";
 
-	static readonly DiagnosticDescriptor RBI0001 = new (DiagnosticId, Title, MessageFormat, Category,
+	internal static readonly DiagnosticDescriptor RBI0001 = new (DiagnosticId, Title, MessageFormat, Category,
 		DiagnosticSeverity.Error, isEnabledByDefault: true, description: Description);
 
 	public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } =

src/rgen/Microsoft.Macios.Generator.Sample/Microsoft.Macios.Generator.Sample.csproj

@@ -1,11 +1,12 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net$(BundledNETCoreAppTargetFrameworkVersion)</TargetFramework>
+        <TargetFramework>net$(BundledNETCoreAppTargetFrameworkVersion)-ios</TargetFramework>
         <Nullable>enable</Nullable>
         <RootNamespace>Microsoft.Macios.Generator.Sample</RootNamespace>
         <NoWarn>APL0003</NoWarn>
         <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+        <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
     </PropertyGroup>
 
     <ItemGroup>

src/rgen/Microsoft.Macios.Generator/Attributes/FieldData.cs

@@ -1,51 +1,82 @@
+using System;
 using System.Diagnostics.CodeAnalysis;
 using Microsoft.CodeAnalysis;
+using Microsoft.Macios.Generator.Extensions;
 
 namespace Microsoft.Macios.Generator.Attributes;
 
-record FieldData {
+readonly struct FieldData<T> where T : Enum {
 	public string SymbolName { get; }
-	public string? LibraryName { get; private set; }
+	public string? LibraryName { get; }
 
-	FieldData (string symbolName, string? libraryName = null)
+	public T? Flags { get; } = default;
+
+	FieldData (string symbolName, string? libraryName, T? flags)
 	{
 		SymbolName = symbolName;
 		LibraryName = libraryName;
+		Flags = flags;
 	}
 
-	public static bool TryParse (SyntaxNode attributeSyntax, AttributeData attributeData,
-		[NotNullWhen (true)] out FieldData? data)
+	public static bool TryParse (AttributeData attributeData,
+		[NotNullWhen (true)] out FieldData<T>? data)
 	{
 		data = default;
 
 		var count = attributeData.ConstructorArguments.Length;
+		string? symbolName;
+		string? libraryName = null;
+		T? flags = default;
 		switch (count) {
 		case 1:
-			data = new ((string) attributeData.ConstructorArguments [0].Value!);
+			if (!attributeData.ConstructorArguments [0].TryGetIdentifier (out symbolName)) {
+				return false;
+			}
 			break;
 		case 2:
-			data = new ((string) attributeData.ConstructorArguments [0].Value!,
-				(string) attributeData.ConstructorArguments [1].Value!);
+			if (!attributeData.ConstructorArguments [0].TryGetIdentifier (out symbolName)) {
+				return false;
+			}
+			switch (attributeData.ConstructorArguments [1].Value) {
+			// there are two possible cases here:
+			// 1. The second argument is a string
+			// 2. The second argument is an enum
+			case T enumValue:
+				flags = enumValue;
+				break;
+			case string lib:
+				libraryName = lib;
+				break;
+			default:
+				// unexpected value :/
+				return false;
+			}
 			break;
 		default:
 			// 0 should not be an option..
 			return false;
 		}
 
-		if (attributeData.NamedArguments.Length == 0)
+		if (attributeData.NamedArguments.Length == 0) {
+			data = new (symbolName, libraryName, flags);
 			return true;
+		}
 
 		// LibraryName can be a param value
 		foreach (var (name, value) in attributeData.NamedArguments) {
 			switch (name) {
 			case "LibraryName":
-				data.LibraryName = (string?) value.Value!;
+				libraryName = (string?) value.Value!;
+				break;
+			case "Flags":
+				flags = (T) value.Value!;
 				break;
 			default:
 				data = null;
 				return false;
 			}
 		}
+		data = new (symbolName, libraryName, flags);
 		return true;
 	}
 }

src/rgen/Microsoft.Macios.Generator/Attributes/ObsoletedOSPlatformData.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.CodeAnalysis;
+using Microsoft.Macios.Generator.Extensions;
+using Xamarin.Utils;
+
+namespace Microsoft.Macios.Generator.Attributes;
+
+/// <summary>
+/// Represents the data found in a ObsoletedOSPlatformAttribute.
+/// </summary>
+readonly struct ObsoletedOSPlatformData {
+	/// <summary>
+	/// Obsoleted platform.
+	/// </summary>
+	public ApplePlatform Platform { get; }
+
+	/// <summary>
+	/// Version in which the symbol was obsoleted. The default new Version () value will be
+	/// used when the symbol has been obsoleted in all version.
+	/// </summary>
+	public Version Version { get; }
+
+	/// <summary>
+	/// Optional obsoleted message to report to the user.
+	/// </summary>
+	public string? Message { get; } = default;
+
+	/// <summary>
+	/// Optional url that points to the documentation.
+	/// </summary>
+	public string? Url { get; }
+
+	internal ObsoletedOSPlatformData (string platformName)
+	{
+		(Platform, Version) = platformName.GetPlatformAndVersion ();
+	}
+
+	internal ObsoletedOSPlatformData (string platformName, string? message = null, string? url = null) : this (platformName)
+	{
+		Message = message;
+		Url = url;
+	}
+
+	/// <summary>
+	/// Try to parse the attribute data to retrieve the information of an ObsoletedOSPlatformAttribute.
+	/// </summary>
+	/// <param name="attributeData">The attribute data to be parsed.</param>
+	/// <param name="data">The parsed data. Null if we could not parse the attribute data.</param>
+	/// <returns>True if the data was parsed.</returns>
+	public static bool TryParse (AttributeData attributeData,
+		[NotNullWhen (true)] out ObsoletedOSPlatformData? data)
+	{
+		data = default;
+		string platformName;
+		string? message = null;
+		string? url = null;
+
+		var count = attributeData.ConstructorArguments.Length;
+		switch (count) {
+		case 1:
+			platformName = (string) attributeData.ConstructorArguments [0].Value!;
+			break;
+		case 2:
+			platformName = (string) attributeData.ConstructorArguments [0].Value!;
+			message = (string) attributeData.ConstructorArguments [1].Value!;
+			break;
+		default: // there is not 3 args constructor with a url
+			return false;
+		}
+
+		if (attributeData.NamedArguments.Length == 0) {
+			data = new (platformName, message, url);
+			return true;
+		}
+
+		foreach (var (name, value) in attributeData.NamedArguments) {
+			switch (name) {
+			case "Url":
+				url = (string?) value.Value!;
+				break;
+			case "TypeId": // ignore the type id
+				break;
+			default:
+				data = null;
+				return false;
+			}
+		}
+
+		data = new (platformName, message, url);
+		return true;
+	}
+}