Optimize object property access for StaticString keys

Author: kateinoigakukun

Runtime/src/index.ts

@@ -141,6 +141,7 @@ export class SwiftRuntime {
     importObjects = () => this.wasmImports;
 
     get wasmImports(): ImportedFunctions {
+        const decodeString = JSValue.makeStringDecoder(this.options.sharedMemory == true, this.textDecoder);
         return {
             swjs_set_prop: (
                 ref: ref,
@@ -174,6 +175,39 @@ export class SwiftRuntime {
                 );
             },
 
+            swjs_set_prop_with_string_key: (
+                ref: ref,
+                prop_ptr: pointer,
+                prop_length: number,
+                kind: JSValue.Kind,
+                payload1: number,
+                payload2: number
+            ) => {
+                const memory = this.memory;
+                const obj = memory.getObject(ref);
+                const key = decodeString(prop_ptr, prop_length, memory);
+                const value = JSValue.decode(kind, payload1, payload2, memory);
+                obj[key] = value;
+            },
+            swjs_get_prop_with_string_key: (
+                ref: ref,
+                prop_ptr: pointer,
+                prop_length: number,
+                payload1_ptr: pointer,
+                payload2_ptr: pointer
+            ) => {
+                const memory = this.memory;
+                const obj = memory.getObject(ref);
+                const key = decodeString(prop_ptr, prop_length, memory);
+                const result = obj[key];
+                return JSValue.writeAndReturnKindBits(
+                    result,
+                    payload1_ptr,
+                    payload2_ptr,
+                    false,
+                    memory
+                );
+            },
             swjs_set_subscript: (
                 ref: ref,
                 index: number,
@@ -210,26 +244,11 @@ export class SwiftRuntime {
                 memory.writeUint32(bytes_ptr_result, bytes_ptr);
                 return bytes.length;
             },
-            swjs_decode_string: (
-                // NOTE: TextDecoder can't decode typed arrays backed by SharedArrayBuffer
-                this.options.sharedMemory == true
-                ? ((bytes_ptr: pointer, length: number) => {
-                    const memory = this.memory;
-                    const bytes = memory
-                        .bytes()
-                        .slice(bytes_ptr, bytes_ptr + length);
-                    const string = this.textDecoder.decode(bytes);
-                    return memory.retain(string);
-                })
-                : ((bytes_ptr: pointer, length: number) => {
-                    const memory = this.memory;
-                    const bytes = memory
-                        .bytes()
-                        .subarray(bytes_ptr, bytes_ptr + length);
-                    const string = this.textDecoder.decode(bytes);
-                    return memory.retain(string);
-                })
-            ),
+            swjs_decode_string: (bytes_ptr: pointer, length: number) => {
+                const memory = this.memory;
+                const string = decodeString(bytes_ptr, length, memory);
+                return memory.retain(string);
+            },
             swjs_load_string: (ref: ref, buffer: pointer) => {
                 const memory = this.memory;
                 const bytes = memory.getObject(ref);

Runtime/src/js-value.ts

@@ -48,6 +48,23 @@ export const decode = (
     }
 };
 
+export function makeStringDecoder(sharedMemory: boolean, textDecoder: TextDecoder): (ptr: pointer, length: number, memory: Memory) => string {
+    // NOTE: TextDecoder can't decode typed arrays backed by SharedArrayBuffer
+    return sharedMemory == true
+        ? ((bytes_ptr: pointer, length: number, memory: Memory) => {
+            const bytes = memory
+                .bytes()
+                .slice(bytes_ptr, bytes_ptr + length);
+            return textDecoder.decode(bytes);
+        })
+        : ((bytes_ptr: pointer, length: number, memory: Memory) => {
+            const bytes = memory
+                .bytes()
+                .subarray(bytes_ptr, bytes_ptr + length);
+            return textDecoder.decode(bytes);
+        })
+}
+
 // Note:
 // `decodeValues` assumes that the size of RawJSValue is 16.
 export const decodeArray = (ptr: pointer, length: number, memory: Memory) => {

Runtime/src/types.ts

@@ -35,6 +35,21 @@ export interface ImportedFunctions {
         payload1_ptr: pointer,
         payload2_ptr: pointer
     ): JavaScriptValueKind;
+    swjs_set_prop_with_string_key(
+        ref: number,
+        name: number,
+        prop_ptr: pointer,
+        prop_length: number,
+        payload1: number,
+        payload2: number
+    ): void;
+    swjs_get_prop_with_string_key(
+        ref: number,
+        prop_ptr: pointer,
+        prop_length: number,
+        payload1_ptr: pointer,
+        payload2_ptr: pointer
+    ): JavaScriptValueKind;
     swjs_set_subscript(
         ref: number,
         index: number,

Sources/JavaScriptKit/FundamentalObjects/JSObject.swift

@@ -41,6 +41,24 @@ public class JSObject: Equatable {
         }
     }
 
+    /// Returns the `name` member method binding this object as `this` context.
+    ///
+    /// e.g.
+    /// ```swift
+    /// let document = JSObject.global.document.object!
+    /// let divElement = document.createElement!("div")
+    /// ```
+    ///
+    /// - Parameter name: The name of this object's member to access.
+    /// - Returns: The `name` member method binding this object as `this` context.
+    @_disfavoredOverload
+    public subscript(_ name: StaticString) -> ((ConvertibleToJSValue...) -> JSValue)? {
+        guard let function = self[name].function else { return nil }
+        return { (arguments: ConvertibleToJSValue...) in
+            function(this: self, arguments: arguments)
+        }
+    }
+
     /// Returns the `name` member method binding this object as `this` context.
     ///
     /// e.g.
@@ -62,13 +80,13 @@ public class JSObject: Equatable {
     /// A convenience method of `subscript(_ name: String) -> ((ConvertibleToJSValue...) -> JSValue)?`
     /// to access the member through Dynamic Member Lookup.
     @_disfavoredOverload
-    public subscript(dynamicMember name: String) -> ((ConvertibleToJSValue...) -> JSValue)? {
+    public subscript(dynamicMember name: StaticString) -> ((ConvertibleToJSValue...) -> JSValue)? {
         self[name]
     }
 
     /// A convenience method of `subscript(_ name: String) -> JSValue`
     /// to access the member through Dynamic Member Lookup.
-    public subscript(dynamicMember name: String) -> JSValue {
+    public subscript(dynamicMember name: StaticString) -> JSValue {
         get { self[name] }
         set { self[name] = newValue }
     }
@@ -81,6 +99,14 @@ public class JSObject: Equatable {
         set { setJSValue(this: self, name: JSString(name), value: newValue) }
     }
 
+    /// Access the `name` member dynamically through JavaScript and Swift runtime bridge library.
+    /// - Parameter name: The name of this object's member to access.
+    /// - Returns: The value of the `name` member of this object.
+    public subscript(_ name: StaticString) -> JSValue {
+        get { getJSValue(this: self, name: name) }
+        set { setJSValue(this: self, name: name, value: newValue) }
+    }
+
     /// Access the `name` member dynamically through JavaScript and Swift runtime bridge library.
     /// - Parameter name: The name of this object's member to access.
     /// - Returns: The value of the `name` member of this object.
@@ -197,6 +223,17 @@ public class JSThrowingObject {
         self.base = base
     }
 
+    /// Returns the `name` member method binding this object as `this` context.
+    /// - Parameter name: The name of this object's member to access.
+    /// - Returns: The `name` member method binding this object as `this` context.
+    @_disfavoredOverload
+    public subscript(_ name: StaticString) -> ((ConvertibleToJSValue...) throws -> JSValue)? {
+        guard let function = base[name].function?.throws else { return nil }
+        return { [base] (arguments: ConvertibleToJSValue...) in
+            try function(this: base, arguments: arguments)
+        }
+    }
+
     /// Returns the `name` member method binding this object as `this` context.
     /// - Parameter name: The name of this object's member to access.
     /// - Returns: The `name` member method binding this object as `this` context.
@@ -211,7 +248,7 @@ public class JSThrowingObject {
     /// A convenience method of `subscript(_ name: String) -> ((ConvertibleToJSValue...) throws -> JSValue)?`
     /// to access the member through Dynamic Member Lookup.
     @_disfavoredOverload
-    public subscript(dynamicMember name: String) -> ((ConvertibleToJSValue...) throws -> JSValue)? {
+    public subscript(dynamicMember name: StaticString) -> ((ConvertibleToJSValue...) throws -> JSValue)? {
         self[name]
     }
 }

Sources/JavaScriptKit/JSValue.swift

@@ -103,13 +103,13 @@ public enum JSValue: Equatable {
 public extension JSValue {
     /// An unsafe convenience method of `JSObject.subscript(_ name: String) -> ((ConvertibleToJSValue...) -> JSValue)?`
     /// - Precondition: `self` must be a JavaScript Object and specified member should be a callable object.
-    subscript(dynamicMember name: String) -> ((ConvertibleToJSValue...) -> JSValue) {
+    subscript(dynamicMember name: StaticString) -> ((ConvertibleToJSValue...) -> JSValue) {
         object![dynamicMember: name]!
     }
 
     /// An unsafe convenience method of `JSObject.subscript(_ index: Int) -> JSValue`
     /// - Precondition: `self` must be a JavaScript Object.
-    subscript(dynamicMember name: String) -> JSValue {
+    subscript(dynamicMember name: StaticString) -> JSValue {
         get { self.object![name] }
         set { self.object![name] = newValue }
     }
@@ -194,6 +194,29 @@ extension JSValue: ExpressibleByNilLiteral {
     }
 }
 
+internal func getJSValue(this: JSObject, name: StaticString) -> JSValue {
+    var rawValue = RawJSValue()
+    let rawBitPattern = name.withUTF8Buffer { buffer in
+        swjs_get_prop_with_string_key(
+            this.id, buffer.baseAddress, Int32(buffer.count),
+            &rawValue.payload1, &rawValue.payload2
+        )
+    }
+    rawValue.kind = unsafeBitCast(rawBitPattern, to: JavaScriptValueKind.self)
+    return rawValue.jsValue
+}
+
+internal func setJSValue(this: JSObject, name: StaticString, value: JSValue) {
+    value.withRawJSValue { rawValue in
+        name.withUTF8Buffer { buffer in
+            swjs_set_prop_with_string_key(
+                this.id, buffer.baseAddress, Int32(buffer.count),
+                rawValue.kind, rawValue.payload1, rawValue.payload2
+            )
+        }
+    }
+}
+
 public func getJSValue(this: JSObject, name: JSString) -> JSValue {
     var rawValue = RawJSValue()
     let rawBitPattern = swjs_get_prop(