Move cache pruning to a WorkManager worker (#3649)

- Extend what was `NotificationWorkerFactory` to `WorkerFactory`. This
  can construct arbitrary Workers as long as they provide their own
  Factory for construction.

  The per-Worker factory contains any injected components just for that
  worker type, keeping `WorkerFactory` clean.

- Move `NotificationWorkerFactory` to the new model.

- Implement `PruneCacheWorker`, and remove the code from
 `CachedTimelineViewModel`.

- Create the periodic worker in `TuskyApplication`, ensuring that the
  database is only pruned when the device is idle.

app/src/main/java/com/keylesspalace/tusky/TuskyApplication.kt

@@ -18,15 +18,19 @@ package com.keylesspalace.tusky
 import android.app.Application
 import android.content.SharedPreferences
 import android.util.Log
+import androidx.work.Constraints
+import androidx.work.ExistingPeriodicWorkPolicy
+import androidx.work.PeriodicWorkRequestBuilder
 import androidx.work.WorkManager
 import autodispose2.AutoDisposePlugins
-import com.keylesspalace.tusky.components.notifications.NotificationWorkerFactory
 import com.keylesspalace.tusky.di.AppInjector
 import com.keylesspalace.tusky.settings.PrefKeys
 import com.keylesspalace.tusky.settings.SCHEMA_VERSION
 import com.keylesspalace.tusky.util.APP_THEME_DEFAULT
 import com.keylesspalace.tusky.util.LocaleManager
 import com.keylesspalace.tusky.util.setAppNightMode
+import com.keylesspalace.tusky.worker.PruneCacheWorker
+import com.keylesspalace.tusky.worker.WorkerFactory
 import dagger.android.DispatchingAndroidInjector
 import dagger.android.HasAndroidInjector
 import de.c1710.filemojicompat_defaults.DefaultEmojiPackList
@@ -35,6 +39,7 @@ import de.c1710.filemojicompat_ui.helpers.EmojiPreference
 import io.reactivex.rxjava3.plugins.RxJavaPlugins
 import org.conscrypt.Conscrypt
 import java.security.Security
+import java.util.concurrent.TimeUnit
 import javax.inject.Inject
 
 class TuskyApplication : Application(), HasAndroidInjector {
@@ -42,7 +47,7 @@ class TuskyApplication : Application(), HasAndroidInjector {
     lateinit var androidInjector: DispatchingAndroidInjector<Any>
 
     @Inject
-    lateinit var notificationWorkerFactory: NotificationWorkerFactory
+    lateinit var workerFactory: WorkerFactory
 
     @Inject
     lateinit var localeManager: LocaleManager
@@ -93,9 +98,19 @@ class TuskyApplication : Application(), HasAndroidInjector {
         WorkManager.initialize(
             this,
             androidx.work.Configuration.Builder()
-                .setWorkerFactory(notificationWorkerFactory)
+                .setWorkerFactory(workerFactory)
                 .build()
         )
+
+        // Prune the database every ~ 12 hours when the device is idle.
+        val pruneCacheWorker = PeriodicWorkRequestBuilder<PruneCacheWorker>(12, TimeUnit.HOURS)
+            .setConstraints(Constraints.Builder().setRequiresDeviceIdle(true).build())
+            .build()
+        WorkManager.getInstance(this).enqueueUniquePeriodicWork(
+            PruneCacheWorker.PERIODIC_WORK_TAG,
+            ExistingPeriodicWorkPolicy.KEEP,
+            pruneCacheWorker
+        )
     }
 
     override fun androidInjector() = androidInjector

app/src/main/java/com/keylesspalace/tusky/components/notifications/NotificationHelper.java

@@ -63,6 +63,7 @@ import com.keylesspalace.tusky.entity.Status;
 import com.keylesspalace.tusky.receiver.SendStatusBroadcastReceiver;
 import com.keylesspalace.tusky.util.StringUtils;
 import com.keylesspalace.tusky.viewdata.PollViewDataKt;
+import com.keylesspalace.tusky.worker.NotificationWorker;
 
 import java.util.ArrayList;
 import java.util.Collections;

app/src/main/java/com/keylesspalace/tusky/components/notifications/NotificationWorker.kt

@@ -1,51 +0,0 @@
-/* Copyright 2020 Tusky Contributors
- *
- * This file is part of Tusky.
- *
- * Tusky is free software: you can redistribute it and/or modify it under the terms of the GNU
- * Lesser General Public License as published by the Free Software Foundation, either version 3 of
- * the License, or (at your option) any later version.
- *
- * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
- * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
- * General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License along with Tusky. If
- * not, see <http://www.gnu.org/licenses/>. */
-
-package com.keylesspalace.tusky.components.notifications
-
-import android.content.Context
-import androidx.work.ListenableWorker
-import androidx.work.Worker
-import androidx.work.WorkerFactory
-import androidx.work.WorkerParameters
-import javax.inject.Inject
-
-class NotificationWorker(
-    context: Context,
-    params: WorkerParameters,
-    private val notificationsFetcher: NotificationFetcher
-) : Worker(context, params) {
-
-    override fun doWork(): Result {
-        notificationsFetcher.fetchAndShow()
-        return Result.success()
-    }
-}
-
-class NotificationWorkerFactory @Inject constructor(
-    private val notificationsFetcher: NotificationFetcher
-) : WorkerFactory() {
-
-    override fun createWorker(
-        appContext: Context,
-        workerClassName: String,
-        workerParameters: WorkerParameters
-    ): ListenableWorker? {
-        if (workerClassName == NotificationWorker::class.java.name) {
-            return NotificationWorker(appContext, workerParameters, notificationsFetcher)
-        }
-        return null
-    }
-}

app/src/main/java/com/keylesspalace/tusky/components/timeline/viewmodel/CachedTimelineViewModel.kt

@@ -50,14 +50,11 @@ import com.keylesspalace.tusky.util.EmptyPagingSource
 import com.keylesspalace.tusky.viewdata.StatusViewData
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.asExecutor
-import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.launch
 import retrofit2.HttpException
 import javax.inject.Inject
-import kotlin.time.DurationUnit
-import kotlin.time.toDuration
 
 /**
  * TimelineViewModel that caches all statuses in a local database
@@ -107,16 +104,6 @@ class CachedTimelineViewModel @Inject constructor(
         .flowOn(Dispatchers.Default)
         .cachedIn(viewModelScope)
 
-    init {
-        viewModelScope.launch {
-            delay(5.toDuration(DurationUnit.SECONDS)) // delay so the db is not locked during initial ui refresh
-            accountManager.activeAccount?.id?.let { accountId ->
-                db.timelineDao().cleanup(accountId, MAX_STATUSES_IN_CACHE)
-                db.timelineDao().cleanupAccounts(accountId)
-            }
-        }
-    }
-
     override fun updatePoll(newPoll: Poll, status: StatusViewData.Concrete) {
         // handled by CacheUpdater
     }

app/src/main/java/com/keylesspalace/tusky/di/AppComponent.kt

@@ -34,7 +34,8 @@ import javax.inject.Singleton
         ActivitiesModule::class,
         ServicesModule::class,
         BroadcastReceiverModule::class,
-        ViewModelModule::class
+        ViewModelModule::class,
+        WorkerModule::class
     ]
 )
 interface AppComponent {

app/src/main/java/com/keylesspalace/tusky/di/WorkerModule.kt

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2023 Tusky Contributors
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>.
+ */
+
+package com.keylesspalace.tusky.di
+
+import androidx.work.ListenableWorker
+import com.keylesspalace.tusky.worker.ChildWorkerFactory
+import com.keylesspalace.tusky.worker.NotificationWorker
+import com.keylesspalace.tusky.worker.PruneCacheWorker
+import dagger.Binds
+import dagger.MapKey
+import dagger.Module
+import dagger.multibindings.IntoMap
+import kotlin.reflect.KClass
+
+@Retention(AnnotationRetention.RUNTIME)
+@MapKey
+annotation class WorkerKey(val value: KClass<out ListenableWorker>)
+
+@Module
+abstract class WorkerModule {
+    @Binds
+    @IntoMap
+    @WorkerKey(NotificationWorker::class)
+    internal abstract fun bindNotificationWorkerFactory(worker: NotificationWorker.Factory): ChildWorkerFactory
+
+    @Binds
+    @IntoMap
+    @WorkerKey(PruneCacheWorker::class)
+    internal abstract fun bindPruneCacheWorkerFactory(worker: PruneCacheWorker.Factory): ChildWorkerFactory
+}

app/src/main/java/com/keylesspalace/tusky/receiver/UnifiedPushBroadcastReceiver.kt

@@ -20,11 +20,11 @@ import android.content.Intent
 import android.util.Log
 import androidx.work.OneTimeWorkRequest
 import androidx.work.WorkManager
-import com.keylesspalace.tusky.components.notifications.NotificationWorker
 import com.keylesspalace.tusky.components.notifications.registerUnifiedPushEndpoint
 import com.keylesspalace.tusky.components.notifications.unregisterUnifiedPushEndpoint
 import com.keylesspalace.tusky.db.AccountManager
 import com.keylesspalace.tusky.network.MastodonApi
+import com.keylesspalace.tusky.worker.NotificationWorker
 import dagger.android.AndroidInjection
 import kotlinx.coroutines.DelicateCoroutinesApi
 import kotlinx.coroutines.GlobalScope

app/src/main/java/com/keylesspalace/tusky/worker/NotificationWorker.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2023 Tusky Contributors
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>.
+ */
+
+package com.keylesspalace.tusky.worker
+
+import android.content.Context
+import androidx.work.Worker
+import androidx.work.WorkerParameters
+import com.keylesspalace.tusky.components.notifications.NotificationFetcher
+import javax.inject.Inject
+
+/** Fetch and show new notifications. */
+class NotificationWorker(
+    appContext: Context,
+    params: WorkerParameters,
+    private val notificationsFetcher: NotificationFetcher
+) : Worker(appContext, params) {
+    override fun doWork(): Result {
+        notificationsFetcher.fetchAndShow()
+        return Result.success()
+    }
+
+    class Factory @Inject constructor(
+        private val notificationsFetcher: NotificationFetcher
+    ) : ChildWorkerFactory {
+        override fun createWorker(appContext: Context, params: WorkerParameters): Worker {
+            return NotificationWorker(appContext, params, notificationsFetcher)
+        }
+    }
+}

app/src/main/java/com/keylesspalace/tusky/worker/PruneCacheWorker.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2023 Tusky Contributors
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>.
+ */
+
+package com.keylesspalace.tusky.worker
+
+import android.content.Context
+import android.util.Log
+import androidx.work.CoroutineWorker
+import androidx.work.ListenableWorker
+import androidx.work.WorkerParameters
+import com.keylesspalace.tusky.db.AccountManager
+import com.keylesspalace.tusky.db.AppDatabase
+import javax.inject.Inject
+
+/** Prune the database cache of old statuses. */
+class PruneCacheWorker(
+    appContext: Context,
+    workerParams: WorkerParameters,
+    private val appDatabase: AppDatabase,
+    private val accountManager: AccountManager
+) : CoroutineWorker(appContext, workerParams) {
+    override suspend fun doWork(): Result {
+        for (account in accountManager.accounts) {
+            Log.d(TAG, "Pruning database using account ID: ${account.id}")
+            appDatabase.timelineDao().cleanup(account.id, MAX_STATUSES_IN_CACHE)
+        }
+        return Result.success()
+    }
+
+    companion object {
+        private const val TAG = "PruneCacheWorker"
+        private const val MAX_STATUSES_IN_CACHE = 1000
+        const val PERIODIC_WORK_TAG = "PruneCacheWorker_periodic"
+    }
+
+    class Factory @Inject constructor(
+        private val appDatabase: AppDatabase,
+        private val accountManager: AccountManager
+    ) : ChildWorkerFactory {
+        override fun createWorker(appContext: Context, params: WorkerParameters): ListenableWorker {
+            return PruneCacheWorker(appContext, params, appDatabase, accountManager)
+        }
+    }
+}

app/src/main/java/com/keylesspalace/tusky/worker/WorkerFactory.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2023 Tusky Contributors
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>.
+ */
+
+package com.keylesspalace.tusky.worker
+
+import android.content.Context
+import androidx.work.ListenableWorker
+import androidx.work.WorkerFactory
+import androidx.work.WorkerParameters
+import javax.inject.Inject
+import javax.inject.Provider
+
+/**
+ * Workers implement this and are added to the map in [com.keylesspalace.tusky.di.WorkerModule]
+ * so they can be created by [WorkerFactory.createWorker].
+ */
+interface ChildWorkerFactory {
+    /** Create a new instance of the given worker. */
+    fun createWorker(appContext: Context, params: WorkerParameters): ListenableWorker
+}
+
+/**
+ * Creates workers, delegating to each worker's [ChildWorkerFactory.createWorker] to do the
+ * creation.
+ *
+ * @see [com.keylesspalace.tusky.components.notifications.NotificationWorker]
+ */
+class WorkerFactory @Inject constructor(
+    val workerFactories: Map<Class<out ListenableWorker>, @JvmSuppressWildcards Provider<ChildWorkerFactory>>
+) : WorkerFactory() {
+    override fun createWorker(
+        appContext: Context,
+        workerClassName: String,
+        workerParameters: WorkerParameters
+    ): ListenableWorker? {
+        val key = Class.forName(workerClassName)
+        workerFactories[key]?.let {
+            return it.get().createWorker(appContext, workerParameters)
+        }
+        return null
+    }
+}

gradle/libs.versions.toml

@@ -92,7 +92,7 @@ androidx-sharetarget = { module = "androidx.sharetarget:sharetarget", version.re
 androidx-swiperefreshlayout = { module = "androidx.swiperefreshlayout:swiperefreshlayout", version.ref = "androidx-swiperefresh-layout" }
 androidx-test-junit = { module = "androidx.test.ext:junit", version.ref = "androidx-junit" }
 androidx-viewpager2 = { module = "androidx.viewpager2:viewpager2", version.ref = "androidx-viewpager2" }
-androidx-work-runtime = { module = "androidx.work:work-runtime", version.ref = "androidx-work" }
+androidx-work-runtime-ktx = { module = "androidx.work:work-runtime-ktx", version.ref = "androidx-work" }
 androidx-work-testing = { module = "androidx.work:work-testing", version.ref = "androidx-work" }
 autodispose-android-lifecycle = { module = "com.uber.autodispose2:autodispose-androidx-lifecycle", version.ref = "autodispose" }
 autodispose-core = { module = "com.uber.autodispose2:autodispose", version.ref = "autodispose" }
@@ -146,7 +146,7 @@ androidx = ["androidx-core-ktx", "androidx-appcompat", "androidx-fragment-ktx",
     "androidx-recyclerview", "androidx-exifinterface", "androidx-cardview", "androidx-preference-ktx", "androidx-sharetarget",
     "androidx-emoji2-core", "androidx-emoji2-views-core", "androidx-emoji2-view-helper", "androidx-lifecycle-viewmodel-ktx",
     "androidx-lifecycle-livedata-ktx", "androidx-lifecycle-common-java8", "androidx-lifecycle-reactivestreams-ktx",
-    "androidx-constraintlayout", "androidx-paging-runtime-ktx", "androidx-viewpager2", "androidx-work-runtime",
+    "androidx-constraintlayout", "androidx-paging-runtime-ktx", "androidx-viewpager2", "androidx-work-runtime-ktx",
     "androidx-core-splashscreen", "androidx-activity"]
 autodispose = ["autodispose-core", "autodispose-android-lifecycle"]
 dagger = ["dagger-core", "dagger-android-core", "dagger-android-support"]