Merge pull request #317 from swiftwasm/katei/embedded-typed-array

Unlock `JSTypedArray` for Embedded Swift

Author: kateinoigakukun

Examples/Embedded/Sources/EmbeddedApp/main.swift

@@ -11,18 +11,49 @@ var divElement = document.createElement("div")
 divElement.innerText = .string("Count \(count)")
 _ = document.body.appendChild(divElement)
 
-var buttonElement = document.createElement("button")
-buttonElement.innerText = "Click me"
-buttonElement.onclick = JSValue.object(
+var clickMeElement = document.createElement("button")
+clickMeElement.innerText = "Click me"
+clickMeElement.onclick = JSValue.object(
     JSClosure { _ in
         count += 1
         divElement.innerText = .string("Count \(count)")
         return .undefined
     }
 )
+_ = document.body.appendChild(clickMeElement)
 
-_ = document.body.appendChild(buttonElement)
+var encodeResultElement = document.createElement("pre")
+var textInputElement = document.createElement("input")
+textInputElement.type = "text"
+textInputElement.placeholder = "Enter text to encode to UTF-8"
+textInputElement.oninput = JSValue.object(
+    JSClosure { _ in
+        let textEncoder = JSObject.global.TextEncoder.function!.new()
+        let encode = textEncoder.encode.function!
+        let encodedData = JSTypedArray<UInt8>(
+            unsafelyWrapping: encode(this: textEncoder, textInputElement.value).object!
+        )
+        encodeResultElement.innerText = .string(
+            encodedData.withUnsafeBytes { bytes in
+                bytes.map { hex($0) }.joined(separator: " ")
+            }
+        )
+        return .undefined
+    }
+)
+let encoderContainer = document.createElement("div")
+_ = encoderContainer.appendChild(textInputElement)
+_ = encoderContainer.appendChild(encodeResultElement)
+_ = document.body.appendChild(encoderContainer)
 
 func print(_ message: String) {
     _ = JSObject.global.console.log(message)
 }
+
+func hex(_ value: UInt8) -> String {
+    var result = "0x"
+    let hexChars: [Character] = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F"]
+    result.append(hexChars[Int(value / 16)])
+    result.append(hexChars[Int(value % 16)])
+    return result
+}

Sources/JavaScriptKit/BasicObjects/JSTypedArray.swift

@@ -1,20 +1,21 @@
 //
 //  Created by Manuel Burghard. Licensed unter MIT.
 //
-#if !hasFeature(Embedded)
 import _CJavaScriptKit
 
 /// A protocol that allows a Swift numeric type to be mapped to the JavaScript TypedArray that holds integers of its type
-public protocol TypedArrayElement: ConvertibleToJSValue, ConstructibleFromJSValue {
+public protocol TypedArrayElement {
+    associatedtype Element: ConvertibleToJSValue, ConstructibleFromJSValue = Self
     /// The constructor function for the TypedArray class for this particular kind of number
     static var typedArrayClass: JSFunction { get }
 }
 
 /// A wrapper around all [JavaScript `TypedArray`
 /// classes](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/TypedArray)
 /// that exposes their properties in a type-safe way.
-public class JSTypedArray<Element>: JSBridgedClass, ExpressibleByArrayLiteral where Element: TypedArrayElement {
-    public class var constructor: JSFunction? { Element.typedArrayClass }
+public final class JSTypedArray<Traits>: JSBridgedClass, ExpressibleByArrayLiteral where Traits: TypedArrayElement {
+    public typealias Element = Traits.Element
+    public class var constructor: JSFunction? { Traits.typedArrayClass }
     public var jsObject: JSObject
 
     public subscript(_ index: Int) -> Element {
@@ -139,33 +140,28 @@ public class JSTypedArray<Element>: JSBridgedClass, ExpressibleByArrayLiteral wh
     }
 }
 
-// MARK: - Int and UInt support
-
-// FIXME: Should be updated to support wasm64 when that becomes available.
-func valueForBitWidth<T>(typeName: String, bitWidth: Int, when32: T) -> T {
-    if bitWidth == 32 {
-        return when32
-    } else if bitWidth == 64 {
-        fatalError("64-bit \(typeName)s are not yet supported in JSTypedArray")
-    } else {
-        fatalError(
-            "Unsupported bit width for type \(typeName): \(bitWidth) (hint: stick to fixed-size \(typeName)s to avoid this issue)"
-        )
-    }
-}
-
 extension Int: TypedArrayElement {
-    public static var typedArrayClass: JSFunction { _typedArrayClass.wrappedValue }
-    private static let _typedArrayClass = LazyThreadLocal(initialize: {
-        valueForBitWidth(typeName: "Int", bitWidth: Int.bitWidth, when32: JSObject.global.Int32Array).function!
-    })
+    public static var typedArrayClass: JSFunction {
+        #if _pointerBitWidth(_32)
+        return JSObject.global.Int32Array.function!
+        #elseif _pointerBitWidth(_64)
+        return JSObject.global.Int64Array.function!
+        #else
+        #error("Unsupported pointer width")
+        #endif
+    }
 }
 
 extension UInt: TypedArrayElement {
-    public static var typedArrayClass: JSFunction { _typedArrayClass.wrappedValue }
-    private static let _typedArrayClass = LazyThreadLocal(initialize: {
-        valueForBitWidth(typeName: "UInt", bitWidth: Int.bitWidth, when32: JSObject.global.Uint32Array).function!
-    })
+    public static var typedArrayClass: JSFunction {
+        #if _pointerBitWidth(_32)
+        return JSObject.global.Uint32Array.function!
+        #elseif _pointerBitWidth(_64)
+        return JSObject.global.Uint64Array.function!
+        #else
+        #error("Unsupported pointer width")
+        #endif
+    }
 }
 
 extension Int8: TypedArrayElement {
@@ -176,13 +172,6 @@ extension UInt8: TypedArrayElement {
     public static var typedArrayClass: JSFunction { JSObject.global.Uint8Array.function! }
 }
 
-/// A wrapper around [the JavaScript `Uint8ClampedArray`
-/// class](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array)
-/// that exposes its properties in a type-safe and Swifty way.
-public class JSUInt8ClampedArray: JSTypedArray<UInt8> {
-    override public class var constructor: JSFunction? { JSObject.global.Uint8ClampedArray.function! }
-}
-
 extension Int16: TypedArrayElement {
     public static var typedArrayClass: JSFunction { JSObject.global.Int16Array.function! }
 }
@@ -206,4 +195,10 @@ extension Float32: TypedArrayElement {
 extension Float64: TypedArrayElement {
     public static var typedArrayClass: JSFunction { JSObject.global.Float64Array.function! }
 }
-#endif
+
+public enum JSUInt8Clamped: TypedArrayElement {
+    public typealias Element = UInt8
+    public static var typedArrayClass: JSFunction { JSObject.global.Uint8ClampedArray.function! }
+}
+
+public typealias JSUInt8ClampedArray = JSTypedArray<JSUInt8Clamped>

Tests/JavaScriptKitTests/JSTypedArrayTests.swift

@@ -17,8 +17,8 @@ final class JSTypedArrayTests: XCTestCase {
     }
 
     func testTypedArray() {
-        func checkArray<T>(_ array: [T]) where T: TypedArrayElement & Equatable {
-            XCTAssertEqual(toString(JSTypedArray(array).jsValue.object!), jsStringify(array))
+        func checkArray<T>(_ array: [T]) where T: TypedArrayElement & Equatable, T.Element == T {
+            XCTAssertEqual(toString(JSTypedArray<T>(array).jsValue.object!), jsStringify(array))
             checkArrayUnsafeBytes(array)
         }
 
@@ -30,20 +30,20 @@ final class JSTypedArrayTests: XCTestCase {
             array.map({ String(describing: $0) }).joined(separator: ",")
         }
 
-        func checkArrayUnsafeBytes<T>(_ array: [T]) where T: TypedArrayElement & Equatable {
-            let copyOfArray: [T] = JSTypedArray(array).withUnsafeBytes { buffer in
+        func checkArrayUnsafeBytes<T>(_ array: [T]) where T: TypedArrayElement & Equatable, T.Element == T {
+            let copyOfArray: [T] = JSTypedArray<T>(array).withUnsafeBytes { buffer in
                 Array(buffer)
             }
             XCTAssertEqual(copyOfArray, array)
         }
 
         let numbers = [UInt8](0...255)
-        let typedArray = JSTypedArray(numbers)
+        let typedArray = JSTypedArray<UInt8>(numbers)
         XCTAssertEqual(typedArray[12], 12)
         XCTAssertEqual(numbers.count, typedArray.lengthInBytes)
 
         let numbersSet = Set(0...255)
-        let typedArrayFromSet = JSTypedArray(numbersSet)
+        let typedArrayFromSet = JSTypedArray<Int>(numbersSet)
         XCTAssertEqual(typedArrayFromSet.jsObject.length, 256)
         XCTAssertEqual(typedArrayFromSet.lengthInBytes, 256 * MemoryLayout<Int>.size)
 
@@ -63,7 +63,7 @@ final class JSTypedArrayTests: XCTestCase {
             0, 1, .pi, .greatestFiniteMagnitude, .infinity, .leastNonzeroMagnitude,
             .leastNormalMagnitude, 42,
         ]
-        let jsFloat32Array = JSTypedArray(float32Array)
+        let jsFloat32Array = JSTypedArray<Float32>(float32Array)
         for (i, num) in float32Array.enumerated() {
             XCTAssertEqual(num, jsFloat32Array[i])
         }
@@ -72,7 +72,7 @@ final class JSTypedArrayTests: XCTestCase {
             0, 1, .pi, .greatestFiniteMagnitude, .infinity, .leastNonzeroMagnitude,
             .leastNormalMagnitude, 42,
         ]
-        let jsFloat64Array = JSTypedArray(float64Array)
+        let jsFloat64Array = JSTypedArray<Float64>(float64Array)
         for (i, num) in float64Array.enumerated() {
             XCTAssertEqual(num, jsFloat64Array[i])
         }