Better leverage Projection.toType(Reference|Expression) (#444)

Generator/Sources/ProjectionModel/Projection+conversion.swift

@@ -72,6 +72,17 @@ extension Projection {
         return result
     }
 
+    public func toBindingType(_ type: TypeDefinition) throws -> SwiftType {
+        .named(try toBindingTypeName(type))
+    }
+
+    public func toBindingType(_ type: BoundType) throws -> SwiftType {
+        let definitionBindingType = try toBindingType(type.definition)
+        return type.genericArgs.isEmpty
+            ? definitionBindingType
+            : definitionBindingType.member(try Projection.toBindingInstantiationTypeName(genericArgs: type.genericArgs))
+    }
+
     public static func getSwiftAttributes(_ member: any Attributable) throws -> [SwiftAttribute] {
         // We recognize any attribute called SwiftAttribute and expect it has a field called Literal,
         // ideally that would be a positional argument, but IDL doesn't seem to have a syntax for that.

Generator/Sources/ProjectionModel/Projection+params.swift

@@ -12,7 +12,7 @@ extension Projection {
 
     public func toParameter(label: String = "_", _ param: Param, genericTypeArgs: [TypeNode] = []) throws -> SwiftParam {
         SwiftParam(label: label, name: toParamName(param), `inout`: param.isByRef,
-            type: try genericTypeArgs.isEmpty ? toType(param.type) : toType(param.type.bindGenericParams(typeArgs: genericTypeArgs)))
+            type: try toTypeExpression(genericTypeArgs.isEmpty ? param.type : param.type.bindGenericParams(typeArgs: genericTypeArgs)))
     }
 
     public func getParamBinding(_ param: ParamBase, genericTypeArgs: [TypeNode] = []) throws -> ParamProjection {

Generator/Sources/ProjectionModel/Projection+types.swift

@@ -3,28 +3,38 @@ import WindowsMetadata
 import CodeWriters
 
 extension Projection {
-    public func toType(_ type: TypeNode) throws -> SwiftType {
+    public func toTypeExpression(_ type: TypeNode, outerNullable: Bool = true) throws -> SwiftType {
         switch type {
-            case let .bound(type):
-                return try toType(type)
+            case let .bound(boundType):
+                if let specialTypeBinding = try getSpecialTypeBinding(boundType) {
+                    if boundType.definition.namespace == "System", boundType.definition.name == "Object", !outerNullable {
+                        return specialTypeBinding.swiftType.unwrapOptional()
+                    }
+                    return specialTypeBinding.swiftType
+                }
+
+                let swiftType = try SwiftType.named(
+                    toTypeName(boundType.definition),
+                    genericArgs: boundType.genericArgs.map { try toTypeExpression($0) })
+                return boundType.definition.isReferenceType && outerNullable ? swiftType.optional() : swiftType
             case let .genericParam(param):
                 return .named(param.name)
             case let .array(of: element):
-                return .array(element: try toType(element))
+                return .array(element: try toTypeExpression(element))
             default:
                 fatalError("Not implemented: Swift representation of values of type \(type)")
         }
     }
 
-    public func toType(_ boundType: BoundType, nullable: Bool = true) throws -> SwiftType {
+    public func toTypeReference(_ boundType: BoundType) throws -> SwiftType {
+        // getSpecialTypeBinding returns a type expression, which includes the optional wrapping.
         if let specialTypeBinding = try getSpecialTypeBinding(boundType) {
-            return specialTypeBinding.swiftType
+            return specialTypeBinding.swiftType.unwrapOptional()
         }
 
-        let swiftObjectType: SwiftType = .named(
+        return .named(
             try toTypeName(boundType.definition),
-            genericArgs: try boundType.genericArgs.map { try toType($0) })
-        return boundType.definition.isReferenceType && nullable ? swiftObjectType.optional() : swiftObjectType
+            genericArgs: try boundType.genericArgs.map { try toTypeExpression($0) })
     }
 
     public func isPODBinding(_ typeDefinition: TypeDefinition) throws -> Bool {
@@ -60,9 +70,8 @@ extension Projection {
         try enumDefinition.attributes.contains(where: { try $0.type.name == "SwiftEnumAttribute" }) && !enumDefinition.isFlags
     }
 
-    public func toReturnType(_ type: TypeNode, typeGenericArgs: [TypeNode]? = nil) throws -> SwiftType {
-        let swiftType = try toType(type.bindGenericParams(typeArgs: typeGenericArgs))
-        return isNullAsErrorEligible(type) ? swiftType.unwrapOptional() : swiftType
+    public func toReturnType(_ type: TypeNode) throws -> SwiftType {
+        try toTypeExpression(type, outerNullable: !isNullAsErrorEligible(type))
     }
 
     public func getTypeBinding(_ type: TypeNode) throws -> TypeProjection {
@@ -108,23 +117,12 @@ extension Projection {
             abiType = .unsafeMutablePointer(pointee: abiType).optional()
         }
 
-        let bindingType: SwiftType = try {
-            let bindingTypeName = try toBindingTypeName(type.definition)
-            if type.genericArgs.isEmpty {
-                return .named(bindingTypeName)
-            }
-            else {
-                return .named(bindingTypeName)
-                    .member(try Projection.toBindingInstantiationTypeName(genericArgs: type.genericArgs))
-            }
-        }()
-
         return TypeProjection(
             abiType: abiType,
             abiDefaultValue: type.definition.isReferenceType ? "nil" : .defaultInitializer,
-            swiftType: try toType(type.asNode),
+            swiftType: try toTypeExpression(type.asNode),
             swiftDefaultValue: type.definition.isReferenceType ? "nil" : .defaultInitializer,
-            bindingType: bindingType,
+            bindingType: try toBindingType(type),
             kind: try isPODBinding(type.definition) ? .pod : .allocating)
     }
 

Generator/Sources/ProjectionModel/SupportModules.swift

@@ -33,6 +33,11 @@ extension SupportModules.COM {
     public static var comBinding: SwiftType { moduleType.member("COMBinding") }
     public static var comTwoWayBinding: SwiftType { moduleType.member("COMTwoWayBinding") }
 
+    public static var comImport: SwiftType { moduleType.member("COMImport") }
+    public static func comImport(of type: SwiftType) -> SwiftType {
+        moduleType.member("COMImport", genericArgs: [type])
+    }
+
     public static var comEmbedding: SwiftType { moduleType.member("COMEmbedding") }
 
     public static var comReference: SwiftType { moduleType.member("COMReference") }

Generator/Sources/SwiftWinRT/Writing/ABIBinding.swift

@@ -8,10 +8,11 @@ import struct Foundation.UUID
 /// Writes a type or extension providing the ABIBinding conformance for a given projected WinRT type.
 internal func writeABIBindingConformance(_ typeDefinition: TypeDefinition, genericArgs: [TypeNode]?, projection: Projection, to writer: SwiftSourceFileWriter) throws {
     if SupportModules.WinRT.getBuiltInTypeKind(typeDefinition) == .definitionAndBinding {
-        // The support module already defines a projection, just import and reexport it.
+        // The support module already defines a projection, just reexport it.
         if typeDefinition.isReferenceType {
-            let bindingTypeName = try projection.toBindingTypeName(typeDefinition)
-            writer.writeImport(exported: true, kind: .enum, module: SupportModules.WinRT.moduleName, symbolName: bindingTypeName)
+            writer.writeImport(exported: true, kind: .enum,
+                module: SupportModules.WinRT.moduleName,
+                symbolName: try projection.toBindingTypeName(typeDefinition))
         }
         else {
             // The struct conforms to ABIBinding itself, and we already imported it.
@@ -30,7 +31,7 @@ internal func writeABIBindingConformance(_ typeDefinition: TypeDefinition, gener
         let enumBindingProtocol = try projection.isSwiftEnumEligible(enumDefinition)
             ? SupportModules.WinRT.closedEnumBinding : SupportModules.WinRT.openEnumBinding
         try writer.writeExtension(
-                type: .named(projection.toTypeName(enumDefinition)),
+                type: projection.toTypeReference(enumDefinition.bindType()),
                 protocolConformances: [ enumBindingProtocol ]) { writer in
             // public static var typeName: String { "..." }
             try writeTypeNameProperty(type: enumDefinition.bindType(), to: writer)
@@ -59,20 +60,20 @@ internal func writeABIBindingConformance(_ typeDefinition: TypeDefinition, gener
         // Non-generic type, create a standard projection type.
         // enum IVectorBinding: WinRTBinding... {}
         try writeInterfaceOrDelegateBindingType(typeDefinition.bindType(),
-            projectionName: try projection.toBindingTypeName(typeDefinition), projection: projection, to: writer)
+            name: try projection.toBindingTypeName(typeDefinition),
+            projection: projection, to: writer)
     }
     else if let genericArgs {
         // Generic type specialization. Create a projection for the specialization.
         // extension IVectorBinding {
         //     internal final class Boolean: WinRTBinding... {}
         // }
         try writer.writeExtension(
-                type: .named(projection.toBindingTypeName(typeDefinition))) { writer in
+                type: projection.toBindingType(typeDefinition)) { writer in
             try writeInterfaceOrDelegateBindingType(
                 typeDefinition.bindType(genericArgs: genericArgs),
-                projectionName: try Projection.toBindingInstantiationTypeName(genericArgs: genericArgs),
-                projection: projection,
-                to: writer)
+                name: try Projection.toBindingInstantiationTypeName(genericArgs: genericArgs),
+                projection: projection, to: writer)
         }
     }
     else {
@@ -256,21 +257,19 @@ fileprivate func writeClassBindingType(
         to writer: SwiftSourceFileWriter) throws {
     assert(!classDefinition.isStatic)
 
-    let projectionProtocol = try classDefinition.hasAttribute(ComposableAttribute.self)
+    let bindingProtocol = try classDefinition.hasAttribute(ComposableAttribute.self)
         ? SupportModules.WinRT.composableClassBinding
         : SupportModules.WinRT.runtimeClassBinding
 
-    let bindingTypeName = try projection.toBindingTypeName(classDefinition)
     try writer.writeClass(
             visibility: Projection.toVisibility(classDefinition.visibility),
-            name: bindingTypeName, protocolConformances: [ projectionProtocol ]) { writer throws in
-        let typeName = try projection.toTypeName(classDefinition)
-
+            name: projection.toBindingTypeName(classDefinition),
+            protocolConformances: [ bindingProtocol ]) { writer throws in
         try writeReferenceTypeBindingConformance(
             apiType: classDefinition.bindType(),
             abiType: defaultInterface.asBoundType,
             wrapImpl: { writer, paramName in
-                writer.writeStatement("\(typeName)(_wrapping: consume \(paramName))")
+                writer.writeStatement(".init(_wrapping: consume \(paramName))")
             },
             projection: projection,
             to: writer)
@@ -289,8 +288,7 @@ fileprivate func writeComposableClassOuterObject(
 
     let baseOuterObjectClass: SwiftType
     if let base = try classDefinition.base, try base.definition.base != nil {
-        baseOuterObjectClass = .named(try projection.toBindingTypeName(base.definition))
-            .member(outerObjectClassName)
+        baseOuterObjectClass = try projection.toBindingType(base.definition).member(outerObjectClassName)
     } else {
         baseOuterObjectClass = SupportModules.WinRT.composableClass_outerObject
     }
@@ -306,8 +304,6 @@ fileprivate func writeComposableClassOuterObject(
         return
     }
 
-    let classSwiftType: SwiftType = .named(try projection.toTypeName(classDefinition))
-
     try writer.writeClass(
             visibility: .open,
             name: outerObjectClassName,
@@ -326,7 +322,7 @@ fileprivate func writeComposableClassOuterObject(
 
                     // _ifoo.initOwner(owner as! MyClass)
                     // return _ifoo.toCOM()
-                    writer.writeStatement("\(propertyName).initOwner(owner as! \(classSwiftType))")
+                    writer.writeStatement("\(propertyName).initOwner(owner as! SwiftObject)")
                     writer.writeReturnStatement(value: "\(propertyName).toCOM()")
                 }
             }
@@ -356,19 +352,19 @@ fileprivate func writeComposableClassOuterObject(
 
 fileprivate func writeInterfaceOrDelegateBindingType(
         _ type: BoundType,
-        projectionName: String,
+        name: String,
         projection: Projection,
         to writer: some SwiftDeclarationWriter) throws {
     precondition(type.definition is InterfaceDefinition || type.definition is DelegateDefinition)
-    let projectionProtocol = type.definition is InterfaceDefinition
+    let bindingProtocol = type.definition is InterfaceDefinition
         ? SupportModules.WinRT.interfaceBinding : SupportModules.WinRT.delegateBinding
 
     // Projections of generic instantiations are not owned by any specific module.
     // Making them internal avoids clashes between redundant definitions across modules.
     try writer.writeEnum(
             visibility: type.genericArgs.isEmpty ? Projection.toVisibility(type.definition.visibility) : .internal,
-            name: projectionName,
-            protocolConformances: [ projectionProtocol ]) { writer throws in
+            name: name,
+            protocolConformances: [ bindingProtocol ]) { writer throws in
 
         let importClassName = "Import"
 
@@ -397,7 +393,8 @@ fileprivate func writeInterfaceOrDelegateBindingType(
         }
 
         try writeCOMImportClass(
-            type, visibility: .private, name: importClassName, projectionName: projectionName,
+            type, visibility: .private, name: importClassName,
+            bindingType: .named(name),
             projection: projection, to: writer)
 
         // public static var virtualTablePointer: UnsafeRawPointer { .init(withUnsafePointer(to: &virtualTable) { $0 }) }
@@ -426,7 +423,7 @@ internal func writeReferenceTypeBindingConformance(
         projection: Projection,
         to writer: SwiftTypeDefinitionWriter) throws {
     writer.writeTypeAlias(visibility: .public, name: "SwiftObject",
-        target: try projection.toType(apiType.asNode).unwrapOptional())
+        target: try projection.toTypeReference(apiType))
     writer.writeTypeAlias(visibility: .public, name: "ABIStruct",
         target: try projection.toABIType(abiType))
 

Generator/Sources/SwiftWinRT/Writing/COMImportClass.swift

@@ -9,25 +9,25 @@ internal func writeCOMImportClass(
         _ type: BoundType,
         visibility: SwiftVisibility,
         name: String,
-        projectionName: String,
+        bindingType: SwiftType,
         projection: Projection,
         to writer: SwiftTypeDefinitionWriter) throws {
-    let importBaseTypeName: String
+    let importBaseType: SwiftType
     let protocolConformances: [SwiftType]
     switch type.definition {
         case let interfaceDefinition as InterfaceDefinition:
-            importBaseTypeName = "WinRTImport"
+            importBaseType = SupportModules.WinRT.winRTImport(of: bindingType)
             protocolConformances = [.named(try projection.toProtocolName(interfaceDefinition)) ]
         case is DelegateDefinition:
-            importBaseTypeName = "COMImport"
+            importBaseType =  SupportModules.COM.comImport(of: bindingType)
             protocolConformances = []
         default: fatalError()
     }
 
     // private final class Import: WinRTImport<IFooBinding>, IFooProtocol {}
     try writer.writeClass(
         visibility: visibility, final: true, name: name,
-        base: .named(importBaseTypeName, genericArgs: [ .named(projectionName) ]),
+        base: importBaseType,
         protocolConformances: protocolConformances) { writer throws in
 
         let interfaces = try type.definition.baseInterfaces.map {
@@ -92,7 +92,7 @@ internal func writeGenericTypeAliases(interfaces: [BoundInterface], projection:
         for (index, genericArg) in interface.genericArgs.enumerated() {
             let genericParamName = interface.definition.genericParams[index].name
             if typeAliases[genericParamName] == nil {
-                typeAliases[genericParamName] = try projection.toType(genericArg)
+                typeAliases[genericParamName] = try projection.toTypeExpression(genericArg)
             }
         }
     }

Generator/Sources/SwiftWinRT/Writing/ClassDefinition.swift

@@ -23,15 +23,13 @@ internal func writeClassDefinition(_ classDefinition: ClassDefinition, projectio
         return
     }
 
-    let bindingTypeName = try projection.toBindingTypeName(classDefinition)
-
     // Both composable and activatable classes can have a base class
     let base: SwiftType
     if let baseClassDefinition = try getRuntimeClassBase(classDefinition) {
-        base = try projection.toType(baseClassDefinition.bindType(), nullable: false)
+        base = try projection.toTypeReference(baseClassDefinition.bindType())
     } else {
-        base = classDefinition.isSealed
-            ? SupportModules.WinRT.winRTImport(of: .named(bindingTypeName))
+        base = try classDefinition.isSealed
+            ? SupportModules.WinRT.winRTImport(of: projection.toBindingType(classDefinition))
             : SupportModules.WinRT.composableClass
     }
 
@@ -259,7 +257,7 @@ fileprivate func writeComposableInitializers(
     let propertyName = SecondaryInterfaces.getPropertyName(factoryInterface.bind())
 
     let baseClassDefinition = try getRuntimeClassBase(classDefinition)
-    let outerObjectType: SwiftType = .named(try projection.toBindingTypeName(classDefinition)).member("OuterObject")
+    let outerObjectType = try projection.toBindingType(classDefinition).member("OuterObject")
 
     for method in factoryInterface.methods {
         // Swift requires "override" on initializers iff the same initializer is defined in the direct base class
@@ -325,9 +323,9 @@ fileprivate func writeDefaultActivatableInitializer(
             override: isOverriding,
             throws: true) { writer in
         let propertyName = SecondaryInterfaces.getPropertyName(interfaceName: "IActivationFactory")
-        let projectionClassName = try projection.toBindingTypeName(classDefinition)
+        let bindingType = try projection.toBindingType(classDefinition)
         writer.writeStatement("let _instance = \(SupportModules.COM.comReference)(transferringRef: try Self.\(propertyName)"
-            + ".activateInstance(binding: \(projectionClassName).self))")
+            + ".activateInstance(binding: \(bindingType).self))")
         if try hasComposableBase(classDefinition) {
             writer.writeStatement("super.init(_wrapping: _instance.cast()) // Transitively casts down to IInspectable")
         }

Generator/Sources/SwiftWinRT/Writing/EnumDefinition.swift

@@ -30,7 +30,7 @@ fileprivate func writeOpenEnumDefinition(_ enumDefinition: EnumDefinition, proje
             name: structName,
             protocolConformances: [.named("CStyleEnum") ]) { writer throws in
 
-        let rawValueType = try projection.toType(enumDefinition.underlyingType.bindNode())
+        let rawValueType = try projection.toTypeExpression(enumDefinition.underlyingType.bindNode())
         writer.writeStoredProperty(visibility: .public, declarator: .var, name: "rawValue", type: rawValueType)
         writer.writeInit(visibility: .public,
             params: [ .init(name: "rawValue", type: rawValueType, defaultValue: "0") ]) {
@@ -90,7 +90,7 @@ fileprivate func writeClosedEnumDefinition(_ enumDefinition: EnumDefinition, pro
             documentation: projection.getDocumentationComment(enumDefinition),
             visibility: Projection.toVisibility(enumDefinition.visibility),
             name: try projection.toTypeName(enumDefinition),
-            rawValueType: try projection.toType(enumDefinition.underlyingType.bindNode()),
+            rawValueType: try projection.toTypeExpression(enumDefinition.underlyingType.bindNode()),
             protocolConformances: [.named("ClosedEnum") ]) { writer throws in
         for field in enumDefinition.fields.filter({ $0.visibility == .public && $0.isStatic }) {
             try writer.writeEnumCase(