1 /* 2 * Copyright (C) 2022 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.unfold.updates 18 19 import android.content.Context 20 import android.hardware.display.DisplayManager 21 import android.os.Handler 22 import android.os.RemoteException 23 import android.os.Trace 24 import androidx.annotation.AnyThread 25 import com.android.systemui.unfold.dagger.UnfoldBg 26 import com.android.systemui.unfold.util.CallbackController 27 import dagger.assisted.Assisted 28 import dagger.assisted.AssistedFactory 29 import dagger.assisted.AssistedInject 30 import java.util.concurrent.CopyOnWriteArrayList 31 import java.util.concurrent.atomic.AtomicInteger 32 33 private const val INVALID_ROTATION = -1 34 35 /** 36 * Allows to subscribe to rotation changes. Updates are provided for the display associated to 37 * [context]. 38 */ 39 class RotationChangeProvider 40 @AssistedInject 41 constructor( 42 private val displayManager: DisplayManager, 43 private val context: Context, 44 @UnfoldBg private val bgHandler: Handler, 45 @Assisted private val callbackHandler: Handler, 46 ) : CallbackController<RotationChangeProvider.RotationListener> { 47 48 private val listeners = CopyOnWriteArrayList<RotationListener>() 49 50 private val displayListener = RotationDisplayListener() 51 private val lastRotation = AtomicInteger(INVALID_ROTATION) 52 addCallbacknull53 override fun addCallback(listener: RotationListener) { 54 bgHandler.post { 55 if (listeners.isEmpty()) { 56 subscribeToRotation() 57 } 58 listeners += listener 59 } 60 } 61 removeCallbacknull62 override fun removeCallback(listener: RotationListener) { 63 bgHandler.post { 64 listeners -= listener 65 if (listeners.isEmpty()) { 66 unsubscribeToRotation() 67 lastRotation.set(INVALID_ROTATION) 68 } 69 } 70 } 71 subscribeToRotationnull72 private fun subscribeToRotation() { 73 try { 74 displayManager.registerDisplayListener(displayListener, callbackHandler) 75 } catch (e: RemoteException) { 76 throw e.rethrowFromSystemServer() 77 } 78 } 79 unsubscribeToRotationnull80 private fun unsubscribeToRotation() { 81 try { 82 displayManager.unregisterDisplayListener(displayListener) 83 } catch (e: RemoteException) { 84 throw e.rethrowFromSystemServer() 85 } 86 } 87 88 /** Gets notified of rotation changes. */ interfacenull89 fun interface RotationListener { 90 /** 91 * Called once rotation changes. This callback is called on the handler provided to 92 * [RotationChangeProvider.Factory.create]. 93 */ 94 @AnyThread fun onRotationChanged(newRotation: Int) 95 } 96 97 private inner class RotationDisplayListener : DisplayManager.DisplayListener { 98 onDisplayChangednull99 override fun onDisplayChanged(displayId: Int) { 100 Trace.beginSection("RotationChangeProvider.RotationDisplayListener#onDisplayChanged") 101 try { 102 val display = context.display ?: return 103 104 if (displayId == display.displayId) { 105 val currentRotation = display.rotation 106 if (lastRotation.compareAndSet(lastRotation.get(), currentRotation)) { 107 listeners.forEach { it.onRotationChanged(currentRotation) } 108 } 109 } 110 } finally { 111 Trace.endSection() 112 } 113 } 114 onDisplayAddednull115 override fun onDisplayAdded(displayId: Int) {} 116 onDisplayRemovednull117 override fun onDisplayRemoved(displayId: Int) {} 118 } 119 120 @AssistedFactory 121 interface Factory { 122 /** Creates a new [RotationChangeProvider] that provides updated using [callbackHandler]. */ createnull123 fun create(callbackHandler: Handler): RotationChangeProvider 124 } 125 } 126