refactor `toInterop` to avoid unnecessary array copies in js when used withing `withResult` (#465)

Co-authored-by: Oleksandr Karpovich <oleksandr.karpovich@jetbrains.com>

skiko/src/commonMain/kotlin/org/jetbrains/skia/impl/Native.kt

@@ -23,21 +23,36 @@ fun getPtr(n: Native?): NativePointer = n?._ptr ?: Native.NullPointer
 
 expect class InteropScope() {
     fun toInterop(string: String?): InteropPointer
+
     fun toInterop(array: ByteArray?): InteropPointer
+    fun toInteropForResult(array: ByteArray?): InteropPointer
     fun InteropPointer.fromInterop(result: ByteArray)
+
     fun toInterop(array: ShortArray?): InteropPointer
+    fun toInteropForResult(array: ShortArray?): InteropPointer
     fun InteropPointer.fromInterop(result: ShortArray)
+
     fun toInterop(array: IntArray?): InteropPointer
+    fun toInteropForResult(array: IntArray?): InteropPointer
     fun InteropPointer.fromInterop(result: IntArray)
+
     fun toInterop(array: LongArray?): InteropPointer
     fun InteropPointer.fromInterop(result: LongArray)
+
     fun toInterop(array: FloatArray?): InteropPointer
+    fun toInteropForResult(array: FloatArray?): InteropPointer
     fun InteropPointer.fromInterop(result: FloatArray)
+
     fun toInterop(array: DoubleArray?): InteropPointer
+    fun toInteropForResult(array: DoubleArray?): InteropPointer
     fun InteropPointer.fromInterop(result: DoubleArray)
+
     fun toInterop(array: NativePointerArray?): InteropPointer
+    fun toInteropForResult(array: NativePointerArray?): InteropPointer
     fun InteropPointer.fromInterop(result: NativePointerArray)
+
     fun toInterop(stringArray: Array<String>?): InteropPointer
+
     fun InteropPointer.fromInteropNativePointerArray(): NativePointerArray
     inline fun <reified T> InteropPointer.fromInterop(decoder: ArrayInteropDecoder<T>): Array<T>
     fun toInteropForArraysOfPointers(interopPointers: Array<InteropPointer>): InteropPointer
@@ -62,14 +77,14 @@ expect class InteropScope() {
 expect inline fun <T> interopScope(block: InteropScope.() -> T): T
 
 inline fun withResult(result: ByteArray, block: InteropScope.(InteropPointer) -> Unit): ByteArray = interopScope {
-    val handle = toInterop(result)
+    val handle = toInteropForResult(result)
     block(handle)
     handle.fromInterop(result)
     result
 }
 
 inline fun withNullableResult(result: ByteArray, block: InteropScope.(InteropPointer) -> Boolean): ByteArray? = interopScope {
-    val handle = toInterop(result)
+    val handle = toInteropForResult(result)
     return if (block(handle)) {
         handle.fromInterop(result)
         result
@@ -79,14 +94,14 @@ inline fun withNullableResult(result: ByteArray, block: InteropScope.(InteropPoi
 }
 
 inline fun withResult(result: FloatArray, block: InteropScope.(InteropPointer) -> Unit): FloatArray = interopScope {
-    val handle = toInterop(result)
+    val handle = toInteropForResult(result)
     block(handle)
     handle.fromInterop(result)
     result
 }
 
 inline fun withNullableResult(result: FloatArray, block: InteropScope.(InteropPointer) -> Boolean): FloatArray? = interopScope {
-    val handle = toInterop(result)
+    val handle = toInteropForResult(result)
     val blockResult = block(handle)
     if (blockResult) {
         handle.fromInterop(result)
@@ -97,14 +112,14 @@ inline fun withNullableResult(result: FloatArray, block: InteropScope.(InteropPo
 }
 
 inline fun withResult(result: IntArray, block: InteropScope.(InteropPointer) -> Unit): IntArray = interopScope {
-    val handle = toInterop(result)
+    val handle = toInteropForResult(result)
     block(handle)
     handle.fromInterop(result)
     result
 }
 
 inline fun withNullableResult(result: IntArray, block: InteropScope.(InteropPointer) -> Boolean): IntArray? = interopScope {
-    val handle = toInterop(result)
+    val handle = toInteropForResult(result)
     return if (block(handle)) {
         handle.fromInterop(result)
         result
@@ -114,21 +129,21 @@ inline fun withNullableResult(result: IntArray, block: InteropScope.(InteropPoin
 }
 
 inline fun withResult(result: ShortArray, block: InteropScope.(InteropPointer) -> Unit): ShortArray = interopScope {
-    val handle = toInterop(result)
+    val handle = toInteropForResult(result)
     block(handle)
     handle.fromInterop(result)
     result
 }
 
 inline fun withResult(result: DoubleArray, block: InteropScope.(InteropPointer) -> Unit): DoubleArray = interopScope {
-    val handle = toInterop(result)
+    val handle = toInteropForResult(result)
     block(handle)
     handle.fromInterop(result)
     result
 }
 
 inline fun withResult(result: NativePointerArray, block: InteropScope.(InteropPointer) -> Unit): NativePointerArray = interopScope {
-    val handle = toInterop(result)
+    val handle = toInteropForResult(result)
     block(handle)
     handle.fromInterop(result)
     result

skiko/src/jsMain/kotlin/org/jetbrains/skia/impl/Native.js.kt

@@ -64,46 +64,65 @@ actual class InteropScope actual constructor() {
         }
     }
 
-    actual fun toInterop(array: ByteArray?): InteropPointer {
+    private fun toInterop(array: ByteArray?, copyArrayToWasm: Boolean): InteropPointer {
         return if (array != null && array.isNotEmpty()) {
             val data = _malloc(array.size)
             elements.add(data)
-            toWasm(data, array)
+            if (copyArrayToWasm) toWasm(data, array)
             data
         } else {
             0
         }
     }
+
+    actual fun toInterop(array: ByteArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = true)
+
+    actual fun toInteropForResult(array: ByteArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = false)
+
     actual fun InteropPointer.fromInterop(result: ShortArray) {
         fromWasm(this@fromInterop, result)
     }
 
-    actual fun toInterop(array: ShortArray?): InteropPointer {
+    private fun toInterop(array: ShortArray?, copyArrayToWasm: Boolean): InteropPointer {
         return if (array != null && array.isNotEmpty()) {
             val data = _malloc(array.size * 2)
             elements.add(data)
-            toWasm(data, array)
+            if (copyArrayToWasm) toWasm(data, array)
             data
         } else {
             0
         }
     }
 
+    actual fun toInterop(array: ShortArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = true)
+
+    actual fun toInteropForResult(array: ShortArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = false)
+
     actual fun InteropPointer.fromInterop(result: IntArray) {
         fromWasm(this@fromInterop, result)
     }
 
-    actual fun toInterop(array: IntArray?): InteropPointer {
+    private fun toInterop(array: IntArray?, copyArrayToWasm: Boolean): InteropPointer {
         return if (array != null && array.isNotEmpty()) {
             val data = _malloc(array.size * 4)
             elements.add(data)
-            toWasm(data, array)
+            if (copyArrayToWasm) toWasm(data, array)
             data
         } else {
             0
         }
     }
 
+    actual fun toInterop(array: IntArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = true)
+
+    actual fun toInteropForResult(array: IntArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = false)
+
     actual fun InteropPointer.fromInterop(result: LongArray) {
         TODO("implement wasm fromInterop(LongArray)")
     }
@@ -116,47 +135,65 @@ actual class InteropScope actual constructor() {
         fromWasm(this@fromInterop, result)
     }
 
-    actual fun toInterop(array: FloatArray?): InteropPointer {
+    private fun toInterop(array: FloatArray?, copyArrayToWasm: Boolean): InteropPointer {
         return if (array != null && array.isNotEmpty()) {
             val data = _malloc(array.size * 4)
             elements.add(data)
-            toWasm(data, array)
+            if (copyArrayToWasm) toWasm(data, array)
             data
         } else {
             0
         }
     }
 
+    actual fun toInterop(array: FloatArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = true)
+
+    actual fun toInteropForResult(array: FloatArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = false)
+
     actual fun InteropPointer.fromInterop(result: DoubleArray) {
         fromWasm(this@fromInterop, result)
     }
 
-    actual fun toInterop(array: DoubleArray?): InteropPointer {
+    private fun toInterop(array: DoubleArray?, copyArrayToWasm: Boolean): InteropPointer {
         return if (array != null && array.isNotEmpty()) {
             val data = _malloc(array.size * 8)
             elements.add(data)
-            toWasm(data, array)
+            if (copyArrayToWasm) toWasm(data, array)
             data
         } else {
             0
         }
     }
 
+    actual fun toInterop(array: DoubleArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = true)
+
+    actual fun toInteropForResult(array: DoubleArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = false)
+
     actual fun InteropPointer.fromInterop(result: ByteArray) {
         fromWasm(this@fromInterop, result)
     }
 
-    actual fun toInterop(array: NativePointerArray?): InteropPointer {
+    private fun toInterop(array: NativePointerArray?, copyArrayToWasm: Boolean): InteropPointer {
         return if (array != null && array.size > 0) {
             val data = _malloc(array.size * 4)
             elements.add(data)
-            toWasm(data, array.backing)
+            if (copyArrayToWasm) toWasm(data, array.backing)
             data
         } else {
             0
         }
     }
 
+    actual fun toInterop(array: NativePointerArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = true)
+
+    actual fun toInteropForResult(array: NativePointerArray?): InteropPointer =
+        toInterop(array = array, copyArrayToWasm = false)
+
     actual fun InteropPointer.fromInterop(result: NativePointerArray) {
         return fromWasm(this@fromInterop, result.backing)
     }

skiko/src/jvmMain/kotlin/org/jetbrains/skia/impl/Native.jvm.kt

@@ -57,20 +57,34 @@ actual inline fun <T> interopScope(block: InteropScope.() -> T): T {
 
 actual open class InteropScope actual constructor() {
     actual fun toInterop(string: String?): InteropPointer = string
+
     actual fun toInterop(array: ByteArray?): InteropPointer = array
+    actual fun toInteropForResult(array: ByteArray?): InteropPointer = toInterop(array)
     actual fun InteropPointer.fromInterop(result: ByteArray) {}
+
     actual fun toInterop(array: ShortArray?): InteropPointer = array
+    actual fun toInteropForResult(array: ShortArray?): InteropPointer = toInterop(array)
     actual fun InteropPointer.fromInterop(result: ShortArray) {}
+
     actual fun toInterop(array: IntArray?): InteropPointer = array
+    actual fun toInteropForResult(array: IntArray?): InteropPointer = toInterop(array)
     actual fun InteropPointer.fromInterop(result: IntArray) {}
+
     actual fun toInterop(array: LongArray?): InteropPointer = array
     actual fun InteropPointer.fromInterop(result: LongArray) {}
+
     actual fun toInterop(array: FloatArray?): InteropPointer = array
+    actual fun toInteropForResult(array: FloatArray?): InteropPointer = toInterop(array)
     actual fun InteropPointer.fromInterop(result: FloatArray) {}
+
     actual fun toInterop(array: DoubleArray?): InteropPointer = array
+    actual fun toInteropForResult(array: DoubleArray?): InteropPointer = toInterop(array)
     actual fun InteropPointer.fromInterop(result: DoubleArray) {}
+
     actual fun toInterop(array: NativePointerArray?): InteropPointer = array?.backing
+    actual fun toInteropForResult(array: NativePointerArray?): InteropPointer = toInterop(array)
     actual fun InteropPointer.fromInterop(result: NativePointerArray) {}
+
     actual fun toInterop(stringArray: Array<String>?): InteropPointer = stringArray
     actual fun InteropPointer.fromInteropNativePointerArray(): NativePointerArray =
         NativePointerArray((this as LongArray).size, this)

skiko/src/nativeMain/kotlin/org/jetbrains/skia/impl/Native.native.kt

@@ -89,6 +89,8 @@ actual class InteropScope actual constructor() {
         }
     }
 
+    actual fun toInteropForResult(array: ByteArray?): InteropPointer = toInterop(array)
+
     actual fun InteropPointer.fromInterop(result: ByteArray) {}
 
     actual fun toInterop(array: ShortArray?): InteropPointer {
@@ -102,6 +104,8 @@ actual class InteropScope actual constructor() {
         }
     }
 
+    actual fun toInteropForResult(array: ShortArray?): InteropPointer = toInterop(array)
+
     actual fun InteropPointer.fromInterop(result: ShortArray) {}
 
     actual fun toInterop(array: IntArray?): InteropPointer {
@@ -115,6 +119,8 @@ actual class InteropScope actual constructor() {
         }
     }
 
+    actual fun toInteropForResult(array: IntArray?): InteropPointer = toInterop(array)
+
     actual fun InteropPointer.fromInterop(result: IntArray) {}
 
     actual fun toInterop(array: LongArray?): InteropPointer {
@@ -141,6 +147,8 @@ actual class InteropScope actual constructor() {
         }
     }
 
+    actual fun toInteropForResult(array: FloatArray?): InteropPointer = toInterop(array)
+
     actual fun InteropPointer.fromInterop(result: FloatArray) {}
 
     actual fun toInterop(array: DoubleArray?): InteropPointer {
@@ -154,6 +162,8 @@ actual class InteropScope actual constructor() {
         }
     }
 
+    actual fun toInteropForResult(array: DoubleArray?): InteropPointer = toInterop(array)
+
     actual fun InteropPointer.fromInterop(result: DoubleArray) {}
 
     actual fun toInterop(array: NativePointerArray?): InteropPointer {
@@ -168,6 +178,8 @@ actual class InteropScope actual constructor() {
         }
     }
 
+    actual fun toInteropForResult(array: NativePointerArray?): InteropPointer = toInterop(array)
+
     actual fun InteropPointer.fromInterop(result: NativePointerArray) {}
 
     actual fun toInterop(stringArray: Array<String>?): InteropPointer {
@@ -271,4 +283,4 @@ private external fun initCallbacks(
     callNativePointer: COpaquePointer,
     callVoid: COpaquePointer,
     dispose: COpaquePointer
-)
+)
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