1 /* <lambda>null2 * Copyright (C) 2024 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.systemui.common.ui.view 18 19 import android.view.Choreographer 20 import android.view.View 21 import com.android.app.tracing.coroutines.TrackTracer 22 import kotlin.coroutines.resume 23 import kotlinx.coroutines.suspendCancellableCoroutine 24 25 /** utilities related to [Choreographer]. */ 26 interface ChoreographerUtils { 27 /** 28 * Waits until the next [view] doFrame is completed. 29 * 30 * Note that this is expected to work properly when called from any thread. If called during a 31 * doFrame, it waits for the next one to be completed. 32 * 33 * This differs from [kotlinx.coroutines.android.awaitFrame] as it uses 34 * [Handler.postAtFrontOfQueue] instead of [Handler.post] when called from a thread different 35 * than the UI thread for that view. Using [Handler.post] might lead to posting the runnable 36 * after a few frame, effectively missing the "next do frame". 37 */ 38 suspend fun waitUntilNextDoFrameDone(view: View) 39 } 40 41 object ChoreographerUtilsImpl : ChoreographerUtils { 42 private val t = TrackTracer("ChoreographerUtils") 43 waitUntilNextDoFrameDonenull44 override suspend fun waitUntilNextDoFrameDone(view: View) { 45 t.traceAsync("waitUntilNextDoFrameDone") { waitUntilNextDoFrameDoneTraced(view) } 46 } 47 waitUntilNextDoFrameDoneTracednull48 suspend fun waitUntilNextDoFrameDoneTraced(view: View) { 49 suspendCancellableCoroutine { cont -> 50 val frameCallback = 51 Choreographer.FrameCallback { 52 t.instant { "We're in doFrame, waiting for it to end." } 53 view.handler.postAtFrontOfQueue { 54 t.instant { "DoFrame ended." } 55 cont.resume(Unit) 56 } 57 } 58 view.runOnUiThreadUrgently { 59 t.instant { "Waiting for next doFrame" } 60 val choreographer = Choreographer.getInstance() 61 cont.invokeOnCancellation { choreographer.removeFrameCallback(frameCallback) } 62 choreographer.postFrameCallback(frameCallback) 63 } 64 } 65 } 66 67 /** 68 * Execute [r] on the view UI thread, taking priority over everything else scheduled there. Runs 69 * directly if we're already in the correct thread. 70 */ runOnUiThreadUrgentlynull71 private fun View.runOnUiThreadUrgently(r: () -> Unit) { 72 if (handler.looper.isCurrentThread) { 73 r() 74 } else { 75 handler.postAtFrontOfQueue(r) 76 } 77 } 78 } 79