Clean up use of closure property wrappers (#59)

This changes improves compatibility of the WebAPIKit library with Embedded Swift. Unsupported concurrency code is excluded when concurrency is not available, including the use of async sequences. Use of closure patterns is cleaned up to use getters and setters directly instead of property wrappers, which reduces binary code size when Embedded Swift is used.

Author: MaxDesiatov

Sources/WebIDLToSwift/ClosurePattern.swift

@@ -1,6 +1,6 @@
 struct ClosurePattern: SwiftRepresentable, Equatable, Hashable, Comparable {
     static func < (lhs: ClosurePattern, rhs: ClosurePattern) -> Bool {
-        lhs.name.source < rhs.name.source
+        lhs.closureType.source < rhs.closureType.source
     }
 
     let nullable: Bool
@@ -22,16 +22,16 @@ struct ClosurePattern: SwiftRepresentable, Equatable, Hashable, Comparable {
         return nullable ? "(\(closure))?" : closure
     }
 
-    private var getter: SwiftSource {
+    func getter(name: SwiftSource) -> SwiftSource {
         let getFunction: SwiftSource
         if nullable {
             getFunction = """
-            guard let function = jsObject[name].function else {
+            guard let function = jsObject[\(name)].function else {
                 return nil
             }
             """
         } else {
-            getFunction = "let function = jsObject[name].function!"
+            getFunction = "let function = jsObject[\(name)].function!"
         }
         let call: SwiftSource = "function(\(sequence: indexes.map { "_toJSValue($\($0))" }))"
         let closureBody: SwiftSource
@@ -66,15 +66,15 @@ struct ClosurePattern: SwiftRepresentable, Equatable, Hashable, Comparable {
         """
     }
 
-    private var setter: SwiftSource {
-        let setClosure: SwiftSource = "jsObject[name] = \(jsClosureWrapper(name: "newValue"))"
+    func setter(name: SwiftSource) -> SwiftSource {
+        let setClosure: SwiftSource = "jsObject[\(name)] = \(jsClosureWrapper(name: "newValue"))"
 
         if nullable {
             return """
                 if let newValue = newValue {
                     \(setClosure)
                 } else {
-                    jsObject[name] = .null
+                    jsObject[\(name)] = .null
                 }
             """
         } else {
@@ -121,6 +121,7 @@ struct ClosurePattern: SwiftRepresentable, Equatable, Hashable, Comparable {
         """
     }
 
+
     var toJSValue: SwiftSource {
         let escaping: SwiftSource = nullable ? "" : "@escaping"
         return """
@@ -132,7 +133,6 @@ struct ClosurePattern: SwiftRepresentable, Equatable, Hashable, Comparable {
 
     var swiftRepresentation: SwiftSource {
         """
-        \(propertyWrapper)
         \(toJSValue)
         """
     }

Sources/WebIDLToSwift/IDLBuilder.swift

@@ -2,7 +2,7 @@ import Foundation
 import WebIDL
 
 enum IDLBuilder {
-    static let basicDependencies = ["ECMAScript", "JavaScriptKit", "JavaScriptEventLoop"]
+    static let basicDependencies = ["ECMAScript", "JavaScriptKit"]
     static let optionalDependencies = ["JavaScriptEventLoop"]
 
     static let preamble = """
@@ -95,9 +95,8 @@ enum IDLBuilder {
     }
 
     static func generateClosureTypes() throws -> SwiftSource {
-        print("Generating closure property wrappers...")
+        print("Generating closure wrappers...")
         return """
-        /* variadic generics please */
         \(lines: ModuleState.closurePatterns.sorted().map(\.swiftRepresentation))
         """
     }

Sources/WebIDLToSwift/MergeDeclarations.swift

@@ -7,9 +7,6 @@ enum DeclarationMerger {
         "CustomElementConstructor",
         "ArrayBufferView",
         "RotationMatrixType",
-        // Mapped to `Int32` manually. This can't be represented as `Int64` due to `BigInt` representation on JS side,
-        // but as a pointer it can't be represented as floating point number either.
-        "GLintptr",
     ]
     static let ignoredIncludeTargets: Set<String> = ["WorkerNavigator"]
     static let validExposures: Set<String> = ["Window"]

Sources/WebIDLToSwift/WebIDL+SwiftRepresentation.swift

@@ -5,7 +5,7 @@ extension IDLArgument: SwiftRepresentable {
         let type: SwiftSource
         if variadic {
             type = "\(idlType)..."
-        } else if idlType.isFunction, !optional, !idlType.nullable {
+        } else if idlType.closurePattern != nil && !optional && !idlType.nullable {
             type = "@escaping \(idlType)"
         } else {
             type = "\(idlType)"
@@ -23,7 +23,7 @@ extension IDLArgument: SwiftRepresentable {
     }
 }
 
-extension IDLAttribute: SwiftRepresentable, Initializable {
+extension IDLAttribute: SwiftRepresentable {
     private var wrapperName: SwiftSource {
         "_\(raw: name)"
     }
@@ -247,12 +247,16 @@ extension MergedInterface: SwiftRepresentable {
         ]
         let access: SwiftSource = openClasses.contains(name) ? "open" : "public"
 
+        let hasAsyncSequence: Bool
         let header: SwiftSource
         if partial {
             header = "public extension \(name)"
+            hasAsyncSequence = false
         } else {
             let inheritance = (parentClasses.isEmpty ? ["JSBridgedClass"] : parentClasses) + mixins
+                .filter { $0 != "AsyncSequence" }
             header = "\(access) class \(name): \(sequence: inheritance.map(SwiftSource.init(_:)))"
+            hasAsyncSequence = mixins.contains { $0 == "AsyncSequence" }
         }
 
         return """
@@ -269,13 +273,22 @@ extension MergedInterface: SwiftRepresentable {
                 """ : "")
 
                 public required init(unsafelyWrapping jsObject: JSObject) {
-                    \(memberInits.joined(separator: "\n"))
                     \(parentClasses.isEmpty ? "self.jsObject = jsObject" : "super.init(unsafelyWrapping: jsObject)")
                 }
             """)
 
             \(body)
         }
+
+        \(hasAsyncSequence ?
+            """
+            #if canImport(JavaScriptEventLoop)
+            public extension \(name): AsyncSequence {}
+            #endif
+            """ :
+            ""
+        )
+
         """
     }
 
@@ -380,11 +393,13 @@ extension IDLIterableDeclaration: SwiftRepresentable, Initializable {
     var swiftRepresentation: SwiftSource {
         if async {
             return """
+            #if canImport(JavaScriptEventLoop)
             public typealias Element = \(idlType[0])
             @available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
             public func makeAsyncIterator() -> ValueIterableAsyncIterator<\(ModuleState.className)> {
                 ValueIterableAsyncIterator(sequence: self)
             }
+            #endif
             """
         } else {
             return """