feat: added WellKnownType (#1962)

Author: TimothyMakkison

InterfaceStubGenerator.Shared/InterfaceStubGenerator.Shared.projitems

@@ -21,6 +21,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Models\MethodModel.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Models\ParameterModel.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Models\TypeConstraint.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Models\WellKnownTYpes.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Parser.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)UniqueNameBuilder.cs" />
   </ItemGroup>

InterfaceStubGenerator.Shared/Models/WellKnownTypes.cs

@@ -0,0 +1,30 @@
+using Microsoft.CodeAnalysis;
+
+namespace Refit.Generator;
+
+public class WellKnownTypes(Compilation compilation)
+{
+    readonly Dictionary<string, INamedTypeSymbol?> cachedTypes = new();
+
+    public INamedTypeSymbol Get<T>() => Get(typeof(T));
+    public INamedTypeSymbol Get(Type type)
+    {
+        return Get(type.FullName ?? throw new InvalidOperationException("Could not get name of type " + type));
+    }
+
+    public INamedTypeSymbol? TryGet(string typeFullName)
+    {
+        if (cachedTypes.TryGetValue(typeFullName, out var typeSymbol))
+        {
+            return typeSymbol;
+        }
+
+        typeSymbol = compilation.GetTypeByMetadataName(typeFullName);
+        cachedTypes.Add(typeFullName, typeSymbol);
+
+        return typeSymbol;
+    }
+
+    INamedTypeSymbol Get(string typeFullName) =>
+        TryGet(typeFullName) ?? throw new InvalidOperationException("Could not get type " + typeFullName);
+}

InterfaceStubGenerator.Shared/Parser.cs

@@ -32,6 +32,8 @@ CancellationToken cancellationToken
         if (compilation == null)
             throw new ArgumentNullException(nameof(compilation));
 
+        var wellKnownTypes = new WellKnownTypes(compilation);
+
         refitInternalNamespace = $"{refitInternalNamespace ?? string.Empty}RefitInternalGenerated";
 
         // Remove - as they are valid in csproj, but invalid in a namespace
@@ -41,8 +43,8 @@ CancellationToken cancellationToken
         // TODO: we should allow source generators to provide source during initialize, so that this step isn't required.
         var options = (CSharpParseOptions)compilation.SyntaxTrees[0].Options;
 
-        var disposableInterfaceSymbol = compilation.GetTypeByMetadataName("System.IDisposable")!;
-        var httpMethodBaseAttributeSymbol = compilation.GetTypeByMetadataName(
+        var disposableInterfaceSymbol = wellKnownTypes.Get(typeof(IDisposable));
+        var httpMethodBaseAttributeSymbol = wellKnownTypes.TryGet(
             "Refit.HttpMethodAttribute"
         );