From 27a5bac5a7c01f81d9a836d2b74634f163700206 Mon Sep 17 00:00:00 2001
From: Nikolay Rykunov <nikolay.rykunov@jetbrains.com>
Date: Mon, 13 Mar 2023 12:43:53 +0100
Subject: [PATCH] Reduce temporary collections creation in
 updatePointerPositions

---
 .../androidx/compose/ui/ComposeScene.skiko.kt | 21 ++++++++++++-------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/ComposeScene.skiko.kt b/compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/ComposeScene.skiko.kt
index 9d2018946ea56..4ec0884b90360 100644
--- a/compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/ComposeScene.skiko.kt
+++ b/compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/ComposeScene.skiko.kt
@@ -493,15 +493,20 @@ class ComposeScene internal constructor(
     }
 
     private fun updatePointerPositions(event: PointerInputEvent) {
-        // touches/styluses positions should be removed from [pointerPositions] if they are not down anymore
-        val releasedPointers = event.pointers.filter { it.type != PointerType.Mouse && !it.down }
-        for (pointer in releasedPointers) {
-            pointerPositions.remove(pointer.id)
-        }
         // update positions for pointers that are down + mouse
-        val pointersToUpdate = event.pointers - releasedPointers.toSet()
-        for (pointer in pointersToUpdate) {
-            pointerPositions[pointer.id] = pointer.position
+        for (pointer in event.pointers) {
+            if (pointer.type == PointerType.Mouse || pointer.down) {
+                pointerPositions[pointer.id] = pointer.position
+            }
+        }
+        // touches/styluses positions should be removed from [pointerPositions] if they are not down anymore
+        val iterator = pointerPositions.iterator()
+        while (iterator.hasNext()) {
+            val pointerId = iterator.next().key
+            val pointer = event.pointers.find { it.id == pointerId } ?: continue
+            if (pointer.type != PointerType.Mouse && !pointer.down) {
+                iterator.remove()
+            }
         }
     }