Hot Paths optimizations for less allocations (#1156)

Improve performance of critical paths by preventing allocating
intermediate objects like lists, arrays,.... (chunked, map,
to*Collection)

---------
Co-authored-by: Ivan Matkov <matkov.ivan@gmail.com>
Co-authored-by: Alexander Maryanovsky <msasha@gmail.com>

skiko/src/awtMain/kotlin/org/jetbrains/skiko/ResourceUtils.kt

 package org.jetbrains.skiko
 
+import org.jetbrains.skiko.internal.fastForEachReversed
+
 internal interface CloseScope {
     fun <T : AutoCloseable> T.autoClose(): T
 }
@@ -33,8 +35,7 @@ internal fun autoCloseScope(body: CloseScope.() -> Unit) {
     try {
         scope.body()
     } finally {
-        for (index in resources.indices.reversed()) {
-            val item = resources[index]
+        resources.fastForEachReversed { item ->
             item.close()
         }
     }

skiko/src/awtMain/kotlin/org/jetbrains/skiko/SkiaLayer.awt.kt

@@ -5,6 +5,7 @@ import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.launch
 import org.jetbrains.skia.*
+import org.jetbrains.skiko.internal.fastForEach
 import org.jetbrains.skiko.redrawer.Redrawer
 import org.jetbrains.skiko.redrawer.RedrawerManager
 import java.awt.Color
@@ -384,8 +385,8 @@ actual open class SkiaLayer internal constructor(
 
     private fun notifyChange(kind: PropertyKind) {
         stateChangeListeners[kind]?.let { handlers ->
-            for (index in handlers.indices) {
-                handlers[index].invoke(this)
+            handlers.fastForEach { handler ->
+                handler.invoke(this)
             }
         }
     }

skiko/src/awtMain/kotlin/org/jetbrains/skiko/swing/SkiaSwingLayer.kt

@@ -9,7 +9,7 @@ import java.awt.GraphicsConfiguration
 import javax.accessibility.AccessibleContext
 import javax.swing.JPanel
 import javax.swing.SwingUtilities.isEventDispatchThread
-
+import org.jetbrains.skiko.internal.fastForEach
 /**
  * Swing component that draws content provided by [renderDelegate] with GPU acceleration using Skia engine.
  *
@@ -44,8 +44,7 @@ open class SkiaSwingLayer(
     private val renderDelegateWithClipping = SkikoRenderDelegate { canvas, width, height, nanoTime ->
         val scale = graphicsConfiguration.defaultTransform.scaleX.toFloat()
         // clipping
-        for (index in clipComponents.indices) {
-            val component = clipComponents[index]
+        clipComponents.fastForEach { component ->
             canvas.cutoutFromClip(component, scale)
         }
         renderDelegate.onRender(canvas, width, height, nanoTime)

skiko/src/commonMain/kotlin/org/jetbrains/skia/FontFeature.kt

@@ -2,6 +2,7 @@ package org.jetbrains.skia
 
 import org.jetbrains.skia.impl.InteropPointer
 import org.jetbrains.skia.impl.InteropScope
+import org.jetbrains.skiko.internal.unpackTo
 
 class FontFeature(val _tag: Int, val value: Int, val start: UInt, val end: UInt) {
 
@@ -141,13 +142,14 @@ class FontFeature(val _tag: Int, val value: Int, val start: UInt, val end: UInt)
         internal fun InteropScope.arrayOfFontFeaturesToInterop(fontFeatures: Array<FontFeature>?): InteropPointer {
             val ints = IntArray(4 * (fontFeatures?.size ?: 0))
 
-            fontFeatures?.forEachIndexed { ix, fontFeature ->
-                val j = ix * 4
-                ints[j] = fontFeature._tag
-                ints[j + 1] = fontFeature.value
-                ints[j + 2] = fontFeature.start.toInt()
-                ints[j + 3] = fontFeature.end.toInt()
-            }
+            fontFeatures?.unpackTo(ints) { feature , arr, index ->
+                arr[index] = feature._tag
+                arr[index + 1] = feature.value
+                arr[index + 2] = feature.start.toInt()
+                arr[index + 3] = feature.end.toInt()
+                //Stepping 4 places for the next feature, because every feature is represented by 4 ints
+                index + 4
+             }
 
             return toInterop(ints)
         }

skiko/src/commonMain/kotlin/org/jetbrains/skia/Rect.kt

@@ -113,9 +113,14 @@ open class Rect constructor(val left: Float, val top: Float, val right: Float, v
 
         internal fun fromInteropPointer(size: Int, block: InteropScope.(InteropPointer) -> Unit): Array<Rect> {
             val result = withResult(FloatArray(size), block)
-            return result.toList().chunked(4).map { (left, top, right, bottom) ->
-                Rect(left, right, top, bottom)
-            }.toTypedArray()
+            return Array(size / 4) { i ->
+                val offset = i * 4
+                val left = result[offset]
+                val top = result[offset + 1]
+                val right = result[offset + 2]
+                val bottom = result[offset + 3]
+                Rect(left = left, top = top, right = right, bottom = bottom)
+            }
         }
 
         internal fun fromInteropPointerNullable(block: (InteropPointer) -> Boolean): Rect? {

skiko/src/commonMain/kotlin/org/jetbrains/skia/Region.kt

@@ -2,6 +2,7 @@ package org.jetbrains.skia
 
 import org.jetbrains.skia.impl.*
 import org.jetbrains.skia.impl.Library.Companion.staticLoad
+import org.jetbrains.skiko.internal.unpackTo
 
 /**
  * Describes a set of pixels as either one integer rectangle or a run-length encoded
@@ -168,11 +169,13 @@ class Region : Managed(Region_nMake(), _FinalizerHolder.PTR) {
     fun setRects(rects: Array<IRect>): Boolean {
         return try {
             val arr = IntArray(rects.size * 4)
-            for (i in rects.indices) {
-                arr[i * 4] = rects[i].left
-                arr[i * 4 + 1] = rects[i].top
-                arr[i * 4 + 2] = rects[i].right
-                arr[i * 4 + 3] = rects[i].bottom
+            rects.unpackTo(arr) { rect, destination, i ->
+                destination[i] = rect.left
+                destination[i + 1] = rect.top
+                destination[i + 2] = rect.right
+                destination[i + 3] = rect.bottom
+                //Stepping 4 places for the next rect
+                i + 4
             }
             Stats.onNativeCall()
             interopScope {

skiko/src/commonMain/kotlin/org/jetbrains/skia/Typeface.kt

@@ -2,6 +2,7 @@ package org.jetbrains.skia
 
 import org.jetbrains.skia.impl.*
 import org.jetbrains.skia.impl.Library.Companion.staticLoad
+import org.jetbrains.skiko.internal.unpackTo
 
 class Typeface internal constructor(ptr: NativePointer) : RefCnt(ptr) {
     companion object {
@@ -150,13 +151,18 @@ class Typeface internal constructor(ptr: NativePointer) : RefCnt(ptr) {
      */
     fun makeClone(variations: Array<FontVariation>, collectionIndex: Int = 0): Typeface {
         return try {
-            if (variations.size == 0) return this
+            if (variations.isEmpty()) return this
             Stats.onNativeCall()
-            val variationsData = variations.asList().flatMap { listOf(it._tag, it.value.toRawBits()) }.toIntArray()
-            val ptr =
-                interopScope { _nMakeClone(_ptr, toInterop(variationsData), 2 * variations.size, collectionIndex) }
+            val variationsCount = variations.size * 2
+            val variationsData = variations.unpackTo(IntArray(variationsCount)) { variation, arr, idx ->
+                arr[idx] = variation._tag
+                arr[idx + 1] = variation.value.toRawBits()
+                //Stepping 2 places for the next variation
+                idx + 2
+            }
+            val ptr = interopScope { _nMakeClone(_ptr, toInterop(variationsData), variationsCount, collectionIndex) }
             require(ptr != NullPointer) {
-                "Failed to clone Typeface $this with $variations"
+                "Failed to clone Typeface $this with ${variations.contentToString()}"
             }
             Typeface(ptr)
         } finally {

skiko/src/commonMain/kotlin/org/jetbrains/skia/paragraph/Shadow.kt

@@ -55,9 +55,16 @@ class Shadow(val color: Int, val offsetX: Float, val offsetY: Float, val blurSig
     companion object
 }
 
-internal fun Shadow.Companion.fromInteropPointer(shadowsCount: Int, block: InteropScope.(InteropPointer) -> Unit): Array<Shadow> {
-    return withResult(IntArray(shadowsCount * 5), block).toList().chunked(5).map { (color, offsetX, offsetY, blurSigmaA, blurSigmaB) ->
+internal inline fun Shadow.Companion.fromInteropPointer(shadowsCount: Int, block: InteropScope.(InteropPointer) -> Unit): Array<Shadow> {
+    val data = withResult(IntArray(shadowsCount * 5), block)
+    return Array(shadowsCount) { i ->
+        val offset = i * 5
+        val color = data[offset]
+        val offsetX = data[offset + 1]
+        val offsetY = data[offset + 2]
+        val blurSigmaA = data[offset + 3]
+        val blurSigmaB = data[offset + 4]
         val blurSigma = (blurSigmaA.toLong() shl 32) or (blurSigmaB.toLong() and 0xFFFFFFFFL)
         Shadow(color, Float.fromBits(offsetX), Float.fromBits(offsetY), Double.fromBits(blurSigma))
-    }.toTypedArray()
+    }
 }
\ No newline at end of file

skiko/src/commonMain/kotlin/org/jetbrains/skiko/internal/CollectionUtils.kt

+package org.jetbrains.skiko.internal
+
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.contract
+
+
+@OptIn(ExperimentalContracts::class)
+internal inline fun <T, R> Array<T>.unpackTo(destinationArray: R, unpackItem: (T, R, Int) -> Int): R {
+    contract {
+        callsInPlace(unpackItem)
+    }
+    var targetIndex = 0
+    for (i in indices) {
+        targetIndex = unpackItem(this[i], destinationArray, targetIndex)
+    }
+    return destinationArray
+}
+
+@OptIn(ExperimentalContracts::class)
+internal inline fun <T> List<T>.fastForEach(action: (T) -> Unit) {
+    contract { callsInPlace(action) }
+    for (index in indices) {
+        val item = get(index)
+        action(item)
+    }
+}
+@OptIn(ExperimentalContracts::class)
+internal inline fun <T> List<T>.fastForEachReversed(action: (T) -> Unit) {
+    contract { callsInPlace(action) }
+    for (index in indices.reversed()) {
+        val item = get(index)
+        action(item)
+    }
+}
+
+@OptIn(ExperimentalContracts::class)
+internal inline fun <T> List<T>.fastForEachIndexed(action: (Int, T) -> Unit) {
+    contract { callsInPlace(action) }
+    for (index in indices) {
+        val item = get(index)
+        action(index, item)
+    }
+}
+
+@OptIn(ExperimentalContracts::class)
+internal inline fun <T> List<T>.fastAny(predicate: (T) -> Boolean): Boolean {
+    contract { callsInPlace(predicate) }
+    fastForEach { if (predicate(it)) return true }
+    return false
+}
+
+@OptIn(ExperimentalContracts::class)
+internal inline fun <T> List<T>.fastNone(predicate: (T) -> Boolean): Boolean {
+    contract { callsInPlace(predicate) }
+    fastForEach { if (predicate(it)) return false }
+    return true
+}
+
+@OptIn(ExperimentalContracts::class)
+internal inline fun <T> List<T>.fastAll(predicate: (T) -> Boolean): Boolean {
+    contract { callsInPlace(predicate) }
+    fastForEach { if (!predicate(it)) return false }
+    return true
+}
\ No newline at end of file

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

@@ -2,6 +2,8 @@
 
 package org.jetbrains.skia.impl
 
+import org.jetbrains.skiko.internal.fastForEach
+
 internal actual class InteropScope actual constructor() {
     private val elements = mutableListOf<NativePointer>()
     private var callbacksInitialized = false
@@ -149,15 +151,12 @@ internal actual class InteropScope actual constructor() {
     }
 
     actual fun toInterop(stringArray: Array<String>?): InteropPointer {
-        return if (stringArray != null && stringArray.isNotEmpty()) {
-            val ptrs = stringArray.map {
-                toInterop(it)
-            }.toIntArray()
+        if (stringArray.isNullOrEmpty()) return 0
 
-            toInterop(ptrs)
-        } else {
-            0
+        val ptrs = IntArray(stringArray.size) { i ->
+            toInterop(stringArray[i])
         }
+        return toInterop(ptrs)
     }
 
     actual fun InteropPointer.fromInteropNativePointerArray(): NativePointerArray {
@@ -237,7 +236,7 @@ internal actual class InteropScope actual constructor() {
     }
 
     actual fun release()  {
-        elements.forEach {
+        elements.fastForEach {
             _free(it)
         }
         elements.clear()

skiko/src/jvmMain/cpp/common/Font.cc

@@ -269,7 +269,7 @@ extern "C" JNIEXPORT void JNICALL Java_org_jetbrains_skia_FontKt__1nGetBounds
 
     for (int i = 0; i < count; ++i) {
         SkRect b = bounds[i];
-        float r[4] = {b.left(), b.right(), b.top(), b.bottom()};
+        float r[4] = {b.left(), b.top(), b.right(), b.bottom()};
         env->SetFloatArrayRegion(res, 4*i, 4, r);
     }
 }

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/GraphicsApi.jvm.kt

 package org.jetbrains.skiko
 
-import kotlin.system.measureNanoTime
-import kotlin.time.Duration
-import kotlin.time.Duration.Companion.nanoseconds
+import org.jetbrains.skiko.internal.fastNone
 
 internal data class NotSupportedAdapter(
     val os: OS,
     val api: GraphicsApi,
-    val pattern: Regex
+    val pattern: String,
+    /** If true, the adapter name should match the pattern exactly. If false, the patters should be the start of the adapter name. */
+    val exactPattern: Boolean = true
 )
 
 private val notSupportedAdapters: List<NotSupportedAdapter> by lazy {
     listOf(
-            NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = Regex("Intel(R) HD Graphics 520")),
-            NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = Regex("Intel(R) HD Graphics 530")),
-            NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = Regex("Intel(R) HD Graphics 4400")),
-            NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = Regex("Intel(R) HD Graphics 4600")),
+        NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = "Intel(R) HD Graphics 520"),
+        NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = "Intel(R) HD Graphics 530"),
+        NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = "Intel(R) HD Graphics 4400"),
+        NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = "Intel(R) HD Graphics 4600"),
 
-            NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = Regex("NVIDIA GeForce GTX 750 Ti")),
-            NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = Regex("NVIDIA GeForce GTX 960M")),
-            NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = Regex("NVIDIA Quadro M2000M")),
+        NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = "NVIDIA GeForce GTX 750 Ti"),
+        NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = "NVIDIA GeForce GTX 960M"),
+        NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.DIRECT3D, pattern = "NVIDIA Quadro M2000M"),
 
-            NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.OPENGL, pattern = Regex("Intel(R) HD Graphics 2000")),
-            NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.OPENGL, pattern = Regex("Intel(R) HD Graphics 3000")),
+        NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.OPENGL, pattern = "Intel(R) HD Graphics 2000"),
+        NotSupportedAdapter(os = OS.Windows, api = GraphicsApi.OPENGL, pattern = "Intel(R) HD Graphics 3000"),
 
-            NotSupportedAdapter(os = OS.Linux, api = GraphicsApi.OPENGL, pattern = Regex("llvmpipe.*")),
-            NotSupportedAdapter(os = OS.Linux, api = GraphicsApi.OPENGL, pattern = Regex("virgl.*"))
+        NotSupportedAdapter(os = OS.Linux, api = GraphicsApi.OPENGL, pattern = "llvmpipe", exactPattern = false),
+        NotSupportedAdapter(os = OS.Linux, api = GraphicsApi.OPENGL, pattern = "virgl", exactPattern = false)
     )
 }
 
 internal fun isVideoCardSupported(api: GraphicsApi, hostOs: OS, name: String): Boolean {
-    return notSupportedAdapters.any { entry ->
-        entry.os == hostOs && entry.api == api && entry.pattern.matches(name)
-    }.not()
+    return notSupportedAdapters.fastNone { adapter ->
+        if ((adapter.os != hostOs) || (adapter.api != api)) return@fastNone false
+
+        val matchesPattern = if (adapter.exactPattern) (adapter.pattern == name) else name.startsWith(adapter.pattern)
+        matchesPattern
+    }
 }
\ No newline at end of file

skiko/src/nativeJsMain/cpp/Font.cc

@@ -259,8 +259,8 @@ SKIKO_EXPORT void org_jetbrains_skia_Font__1nGetBounds
     for (int i = 0; i < count; ++i) {
         SkRect b = bounds[i];
         res[4*i] = b.left();
-        res[4*i + 1] = b.right();
-        res[4*i + 2] = b.top();
+        res[4*i + 1] = b.top();
+        res[4*i + 2] = b.right();
         res[4*i + 3] = b.bottom();
     }
 }

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

@@ -2,6 +2,7 @@ package org.jetbrains.skia.impl
 
 import kotlinx.cinterop.*
 import org.jetbrains.skia.ExternalSymbolName
+import org.jetbrains.skiko.internal.fastForEach
 import kotlin.native.internal.NativePtr
 
 actual abstract class Native actual constructor(ptr: NativePointer) {
@@ -180,13 +181,11 @@ internal actual class InteropScope actual constructor() {
     actual fun InteropPointer.fromInterop(result: NativePointerArray) {}
 
     actual fun toInterop(stringArray: Array<String>?): InteropPointer {
-        if (stringArray == null || stringArray.isEmpty()) return NativePtr.NULL
-
-        val pins = stringArray.toList()
-            .map { convertToZeroTerminatedString(it).pin() }
+        if (stringArray.isNullOrEmpty()) return NativePtr.NULL
 
         val nativePointerArray = NativePointerArray(stringArray.size)
-        pins.forEachIndexed { index, pin ->
+        stringArray.forEachIndexed { index, str ->
+            val pin = convertToZeroTerminatedString(str).pin()
             elements.add(pin)
             nativePointerArray[index] = pin.addressOf(0).rawValue
         }
@@ -207,7 +206,8 @@ internal actual class InteropScope actual constructor() {
     }
 
     actual fun toInteropForArraysOfPointers(interopPointers: Array<InteropPointer>): InteropPointer {
-        return toInterop(interopPointers.map { it.toLong() }.toLongArray())
+        if (interopPointers.isEmpty()) return NativePtr.NULL
+        return toInterop(LongArray(interopPointers.size) { interopPointers[it].toLong() })
     }
 
     actual fun callback(callback: (() -> Unit)?) = callbackImpl(callback)
@@ -222,8 +222,8 @@ internal actual class InteropScope actual constructor() {
     actual fun virtualInteropPointer(method: () -> InteropPointer) = callbackImpl(method)
     actual fun virtualBoolean(method: () -> Boolean) = callbackImpl(method)
 
-    actual fun release()  {
-        elements.forEach {
+    actual fun release() {
+        elements.fastForEach {
             it.unpin()
         }
     }

skiko/src/uikitMain/kotlin/org/jetbrains/skiko/redrawer/MetalRedrawer.uikit.kt

@@ -5,6 +5,7 @@ package org.jetbrains.skiko.redrawer
 import kotlinx.cinterop.*
 import org.jetbrains.skia.*
 import org.jetbrains.skiko.Logger
+import org.jetbrains.skiko.internal.fastForEach
 import platform.Foundation.NSNotificationCenter
 import platform.Foundation.NSRunLoop
 import platform.Foundation.NSSelectorFromString
@@ -154,9 +155,9 @@ internal class MetalRedrawer(
         if (!isApplicationActive) {
             // If application goes background, synchronously schedule all inflightCommandBuffers, as per
             // https://developer.apple.com/documentation/metal/gpu_devices_and_work_submission/preparing_your_metal_app_to_run_in_the_background?language=objc
-            inflightCommandBuffers.forEach {
+            inflightCommandBuffers.fastForEach { commandBuffer ->
                 // Will immediately return for MTLCommandBuffer's which are not in `Commited` status
-                it.waitUntilScheduled()
+                commandBuffer.waitUntilCompleted()
             }
         }
     }

skiko/src/wasmJsMain/kotlin/org/jetbrains/skia/impl/Native.wasm.kt

@@ -2,6 +2,8 @@
 
 package org.jetbrains.skia.impl
 
+import org.jetbrains.skiko.internal.fastForEach
+
 internal actual class InteropScope actual constructor() {
     private val elements = mutableListOf<NativePointer>()
     private var callbacksInitialized = false
@@ -149,15 +151,12 @@ internal actual class InteropScope actual constructor() {
     }
 
     actual fun toInterop(stringArray: Array<String>?): InteropPointer {
-        return if (stringArray != null && stringArray.isNotEmpty()) {
-            val ptrs = stringArray.map {
-                toInterop(it)
-            }.toIntArray()
+        if (stringArray.isNullOrEmpty()) return 0
 
-            toInterop(ptrs)
-        } else {
-            0
+        val ptrs = IntArray(stringArray.size) { i ->
+            toInterop(stringArray[i])
         }
+        return toInterop(ptrs)
     }
 
     actual fun InteropPointer.fromInteropNativePointerArray(): NativePointerArray {
@@ -237,7 +236,7 @@ internal actual class InteropScope actual constructor() {
     }
 
     actual fun release()  {
-        elements.forEach {
+        elements.fastForEach {
             _free(it)
         }
         elements.clear()

skiko/src/webMain/kotlin/org/jetbrains/skia/Actuals.js.kt

@@ -28,7 +28,7 @@ actual class Matcher constructor(private val regex: Regex, private val input: Ch
 @Suppress("RedundantNullableReturnType")
 val LANG: String by lazy {
     val lang: String? = window.navigator.language
-    if (lang == null || lang.isEmpty()) { "en-US" } else { lang }
+    if (lang.isNullOrEmpty()) "en-US" else lang
 }
 
 actual fun defaultLanguageTag(): String = LANG