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Commit 87457295 authored by Fabian Kozynski's avatar Fabian Kozynski
Browse files

Make unregister receiver "sync". 

Before this CL, unregistering a receiver was done asynchronously in
BroadcastDispatcher. This meant that after a call to unregisterReceiver,
there was a period of time in which broadcasts may still be dispatched
for that receiver.

After this change, we mark receivers as pending removal, blocking any
received broadcast to be dispatched while its being removed.

Also, remove the double posting to the same handler thread. Instead, we
use the fact that we know that UserBroadcastDispatcher will only be
called from BroadcastDispatcher in the background thread to prevent
re-posting.

Fixes: 193941146
Test: atest SystemUITests
Test: everything seems to be working fine
Change-Id: I345f4d7ad918381188d553bd2b89643d11ae3d6c
parent 3fda2bf2

packages/SystemUI/src/com/android/systemui/broadcast/ActionReceiver.kt

+11 −2
Original line number Diff line number Diff line
@@ -39,6 +39,13 @@ import java.util.concurrent.atomic.AtomicInteger 
 *

 * This class has no sync controls, so make sure to only make modifications from the background

 * thread.

 *

 * This class takes the following actions:

 * * [registerAction]: action to register this receiver (with the proper filter) with [Context].

 * * [unregisterAction]: action to unregister this receiver with [Context].

 * * [testPendingRemovalAction]: action to check if a particular [BroadcastReceiver] registered

 *   with [BroadcastDispatcher] has been unregistered and is pending removal. See

 *   [PendingRemovalStore].

 */

class ActionReceiver(

    private val action: String,
@@ -46,7 +53,8 @@ class ActionReceiver( 
    private val registerAction: BroadcastReceiver.(IntentFilter) -> Unit,

    private val unregisterAction: BroadcastReceiver.() -> Unit,

    private val bgExecutor: Executor,

    private val logger: BroadcastDispatcherLogger

    private val logger: BroadcastDispatcherLogger,

    private val testPendingRemovalAction: (BroadcastReceiver, Int) -> Boolean

) : BroadcastReceiver(), Dumpable {



    companion object {
@@ -106,7 +114,8 @@ class ActionReceiver( 
        // Immediately return control to ActivityManager

        bgExecutor.execute {

            receiverDatas.forEach {

                if (it.filter.matchCategories(intent.categories) == null) {

                if (it.filter.matchCategories(intent.categories) == null &&

                    !testPendingRemovalAction(it.receiver, userId)) {

                    it.executor.execute {

                        it.receiver.pendingResult = pendingResult

                        it.receiver.onReceive(context, intent)

packages/SystemUI/src/com/android/systemui/broadcast/BroadcastDispatcher.kt

+26 −4
Original line number Diff line number Diff line
@@ -63,13 +63,14 @@ private const val DEBUG = true 
 * Broadcast handling may be asynchronous *without* calling goAsync(), as it's running within sysui

 * and doesn't need to worry about being killed.

 */

open class BroadcastDispatcher constructor (

open class BroadcastDispatcher @JvmOverloads constructor (

    private val context: Context,

    private val bgLooper: Looper,

    private val bgExecutor: Executor,

    private val dumpManager: DumpManager,

    private val logger: BroadcastDispatcherLogger,

    private val userTracker: UserTracker

    private val userTracker: UserTracker,

    private val removalPendingStore: PendingRemovalStore = PendingRemovalStore(logger)

) : Dumpable {



    // Only modify in BG thread
@@ -167,6 +168,7 @@ open class BroadcastDispatcher constructor ( 
     * @param receiver The receiver to unregister. It will be unregistered for all users.

     */

    open fun unregisterReceiver(receiver: BroadcastReceiver) {

        removalPendingStore.tagForRemoval(receiver, UserHandle.USER_ALL)

        handler.obtainMessage(MSG_REMOVE_RECEIVER, receiver).sendToTarget()

    }
@@ -177,13 +179,21 @@ open class BroadcastDispatcher constructor ( 
     * @param user The user associated to the registered [receiver]. It can be [UserHandle.ALL].

     */

    open fun unregisterReceiverForUser(receiver: BroadcastReceiver, user: UserHandle) {

        removalPendingStore.tagForRemoval(receiver, user.identifier)

        handler.obtainMessage(MSG_REMOVE_RECEIVER_FOR_USER, user.identifier, 0, receiver)

                .sendToTarget()

    }



    @VisibleForTesting

    protected open fun createUBRForUser(userId: Int) =

            UserBroadcastDispatcher(context, userId, bgLooper, bgExecutor, logger)

            UserBroadcastDispatcher(

                context,

                userId,

                bgLooper,

                bgExecutor,

                logger,

                removalPendingStore

            )



    override fun dump(pw: PrintWriter, args: Array<out String>) {

        pw.println("Broadcast dispatcher:")
@@ -193,6 +203,8 @@ open class BroadcastDispatcher constructor ( 
            ipw.println("User ${receiversByUser.keyAt(index)}")

            receiversByUser.valueAt(index).dump(ipw, args)

        }

        ipw.println("Pending removal:")

        removalPendingStore.dump(ipw, args)

        ipw.decreaseIndent()

    }
@@ -223,10 +235,20 @@ open class BroadcastDispatcher constructor ( 
                    for (it in 0 until receiversByUser.size()) {

                        receiversByUser.valueAt(it).unregisterReceiver(msg.obj as BroadcastReceiver)

                    }

                    removalPendingStore.clearPendingRemoval(

                        msg.obj as BroadcastReceiver,

                        UserHandle.USER_ALL

                    )

                }



                MSG_REMOVE_RECEIVER_FOR_USER -> {

                    receiversByUser.get(msg.arg1)?.unregisterReceiver(msg.obj as BroadcastReceiver)

                    val userId = if (msg.arg1 == UserHandle.USER_CURRENT) {

                        userTracker.userId

                    } else {

                        msg.arg1

                    }

                    receiversByUser.get(userId)?.unregisterReceiver(msg.obj as BroadcastReceiver)

                    removalPendingStore.clearPendingRemoval(msg.obj as BroadcastReceiver, userId)

                }

                else -> super.handleMessage(msg)

            }

packages/SystemUI/src/com/android/systemui/broadcast/PendingRemovalStore.kt

0 → 100644
+58 −0
Original line number Diff line number Diff line 
package com.android.systemui.broadcast



import android.content.BroadcastReceiver

import android.os.UserHandle

import android.util.SparseSetArray

import androidx.annotation.GuardedBy

import com.android.systemui.Dumpable

import com.android.systemui.broadcast.logging.BroadcastDispatcherLogger

import com.android.systemui.util.indentIfPossible

import java.io.PrintWriter



/**

 * Store information about requests for unregistering receivers from [BroadcastDispatcher], before

 * they have been completely removed from the system.

 *

 * This helps make unregistering a receiver a *sync* operation.

 */

class PendingRemovalStore(

    private val logger: BroadcastDispatcherLogger

) : Dumpable {

    @GuardedBy("pendingRemoval")

    private val pendingRemoval: SparseSetArray<BroadcastReceiver> = SparseSetArray()



    fun tagForRemoval(broadcastReceiver: BroadcastReceiver, userId: Int) {

        logger.logTagForRemoval(userId, broadcastReceiver)

        synchronized(pendingRemoval) {

            pendingRemoval.add(userId, broadcastReceiver)

        }

    }



    fun isPendingRemoval(broadcastReceiver: BroadcastReceiver, userId: Int): Boolean {

        return synchronized(pendingRemoval) {

            pendingRemoval.contains(userId, broadcastReceiver) ||

                pendingRemoval.contains(UserHandle.USER_ALL, broadcastReceiver)

        }

    }



    fun clearPendingRemoval(broadcastReceiver: BroadcastReceiver, userId: Int) {

        synchronized(pendingRemoval) {

            pendingRemoval.remove(userId, broadcastReceiver)

        }

        logger.logClearedAfterRemoval(userId, broadcastReceiver)

    }



    override fun dump(pw: PrintWriter, args: Array<out String>) {

        synchronized(pendingRemoval) {

            pw.indentIfPossible {

                val size = pendingRemoval.size()

                for (i in 0 until size) {

                    val user = pendingRemoval.keyAt(i)

                    print(user)

                    print("->")

                    println(pendingRemoval.get(user))

                }

            }

        }

    }

}
 
 No newline at end of file

packages/SystemUI/src/com/android/systemui/broadcast/UserBroadcastDispatcher.kt

+13 −19
Original line number Diff line number Diff line
@@ -20,12 +20,12 @@ import android.content.BroadcastReceiver 
import android.content.Context

import android.os.Handler

import android.os.Looper

import android.os.Message

import android.os.UserHandle

import android.util.ArrayMap

import android.util.ArraySet

import android.util.Log

import androidx.annotation.VisibleForTesting

import androidx.annotation.WorkerThread

import com.android.internal.util.Preconditions

import com.android.systemui.Dumpable

import com.android.systemui.broadcast.logging.BroadcastDispatcherLogger
@@ -34,8 +34,6 @@ import java.io.PrintWriter 
import java.util.concurrent.Executor

import java.util.concurrent.atomic.AtomicInteger



private const val MSG_REGISTER_RECEIVER = 0

private const val MSG_UNREGISTER_RECEIVER = 1

private const val TAG = "UserBroadcastDispatcher"

private const val DEBUG = false
@@ -50,7 +48,8 @@ open class UserBroadcastDispatcher( 
    private val userId: Int,

    private val bgLooper: Looper,

    private val bgExecutor: Executor,

    private val logger: BroadcastDispatcherLogger

    private val logger: BroadcastDispatcherLogger,

    private val removalPendingStore: PendingRemovalStore

) : Dumpable {



    companion object {
@@ -60,16 +59,6 @@ open class UserBroadcastDispatcher( 
        val index = AtomicInteger(0)

    }



    private val bgHandler = object : Handler(bgLooper) {

        override fun handleMessage(msg: Message) {

            when (msg.what) {

                MSG_REGISTER_RECEIVER -> handleRegisterReceiver(msg.obj as ReceiverData, msg.arg1)

                MSG_UNREGISTER_RECEIVER -> handleUnregisterReceiver(msg.obj as BroadcastReceiver)

                else -> Unit

            }

        }

    }



    // Used for key in actionsToActionsReceivers

    internal data class ReceiverProperties(

        val action: String,
@@ -77,6 +66,8 @@ open class UserBroadcastDispatcher( 
        val permission: String?

    )



    private val bgHandler = Handler(bgLooper)



    // Only modify in BG thread

    @VisibleForTesting

    internal val actionsToActionsReceivers = ArrayMap<ReceiverProperties, ActionReceiver>()
@@ -92,19 +83,21 @@ open class UserBroadcastDispatcher( 
    /**

     * Register a [ReceiverData] for this user.

     */

    @WorkerThread

    fun registerReceiver(receiverData: ReceiverData, flags: Int) {

        bgHandler.obtainMessage(MSG_REGISTER_RECEIVER, flags, 0, receiverData).sendToTarget()

        handleRegisterReceiver(receiverData, flags)

    }



    /**

     * Unregister a given [BroadcastReceiver] for this user.

     */

    @WorkerThread

    fun unregisterReceiver(receiver: BroadcastReceiver) {

        bgHandler.obtainMessage(MSG_UNREGISTER_RECEIVER, receiver).sendToTarget()

        handleUnregisterReceiver(receiver)

    }



    private fun handleRegisterReceiver(receiverData: ReceiverData, flags: Int) {

        Preconditions.checkState(bgHandler.looper.isCurrentThread,

        Preconditions.checkState(bgLooper.isCurrentThread,

                "This method should only be called from BG thread")

        if (DEBUG) Log.w(TAG, "Register receiver: ${receiverData.receiver}")

        receiverToActions
@@ -151,12 +144,13 @@ open class UserBroadcastDispatcher( 
                    }

                },

                bgExecutor,

                logger

                logger,

                removalPendingStore::isPendingRemoval

        )

    }



    private fun handleUnregisterReceiver(receiver: BroadcastReceiver) {

        Preconditions.checkState(bgHandler.looper.isCurrentThread,

        Preconditions.checkState(bgLooper.isCurrentThread,

                "This method should only be called from BG thread")

        if (DEBUG) Log.w(TAG, "Unregister receiver: $receiver")

        receiverToActions.getOrDefault(receiver, mutableSetOf()).forEach {

packages/SystemUI/src/com/android/systemui/broadcast/logging/BroadcastDispatcherLogger.kt

+20 −0
Original line number Diff line number Diff line
@@ -87,6 +87,26 @@ class BroadcastDispatcherLogger @Inject constructor( 
        })

    }



    fun logTagForRemoval(user: Int, receiver: BroadcastReceiver) {

        val receiverString = receiver.toString()

        log(DEBUG, {

            int1 = user

            str1 = receiverString

        }, {

            "Receiver $str1 tagged for removal from user $int1"

        })

    }



    fun logClearedAfterRemoval(user: Int, receiver: BroadcastReceiver) {

        val receiverString = receiver.toString()

        log(DEBUG, {

            int1 = user

            str1 = receiverString

        }, {

            "Receiver $str1 has been completely removed for user $int1"

        })

    }



    fun logReceiverUnregistered(user: Int, receiver: BroadcastReceiver) {

        val receiverString = receiver.toString()

        log(INFO, {