Make AccountPreferenceDataStore injectable (#3653)

This will make tests that need it easier.

- Rename from AccountPreferenceHandler
- Inject its dependencies
- Create an injectable CoroutineScope it can use for launching coroutines
- Use it in AccountPreferences

app/src/main/java/com/keylesspalace/tusky/components/preference/AccountPreferencesFragment.kt

@@ -21,7 +21,6 @@ import android.os.Build
 import android.os.Bundle
 import android.util.Log
 import androidx.annotation.DrawableRes
-import androidx.lifecycle.lifecycleScope
 import androidx.preference.PreferenceFragmentCompat
 import com.google.android.material.color.MaterialColors
 import com.google.android.material.snackbar.Snackbar
@@ -30,7 +29,6 @@ import com.keylesspalace.tusky.BuildConfig
 import com.keylesspalace.tusky.R
 import com.keylesspalace.tusky.TabPreferenceActivity
 import com.keylesspalace.tusky.appstore.EventHub
-import com.keylesspalace.tusky.appstore.PreferenceChangedEvent
 import com.keylesspalace.tusky.components.accountlist.AccountListActivity
 import com.keylesspalace.tusky.components.filters.FiltersActivity
 import com.keylesspalace.tusky.components.followedtags.FollowedTagsActivity
@@ -42,7 +40,7 @@ import com.keylesspalace.tusky.di.Injectable
 import com.keylesspalace.tusky.entity.Account
 import com.keylesspalace.tusky.entity.Status
 import com.keylesspalace.tusky.network.MastodonApi
-import com.keylesspalace.tusky.settings.AccountPreferenceHandler
+import com.keylesspalace.tusky.settings.AccountPreferenceDataStore
 import com.keylesspalace.tusky.settings.PrefKeys
 import com.keylesspalace.tusky.settings.listPreference
 import com.keylesspalace.tusky.settings.makePreferenceScreen
@@ -58,7 +56,6 @@ import com.mikepenz.iconics.IconicsDrawable
 import com.mikepenz.iconics.typeface.library.googlematerial.GoogleMaterial
 import com.mikepenz.iconics.utils.colorInt
 import com.mikepenz.iconics.utils.sizeRes
-import kotlinx.coroutines.launch
 import retrofit2.Call
 import retrofit2.Callback
 import retrofit2.Response
@@ -74,6 +71,9 @@ class AccountPreferencesFragment : PreferenceFragmentCompat(), Injectable {
     @Inject
     lateinit var eventHub: EventHub
 
+    @Inject
+    lateinit var accountPreferenceDataStore: AccountPreferenceDataStore
+
     private val iconSize by unsafeLazy { resources.getDimensionPixelSize(R.dimen.preference_icon_size) }
 
     override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
@@ -245,27 +245,26 @@ class AccountPreferencesFragment : PreferenceFragmentCompat(), Injectable {
             preferenceCategory(R.string.pref_title_timelines) {
                 // TODO having no activeAccount in this fragment does not really make sense, enforce it?
                 //   All other locations here make it optional, however.
-                val accountPreferenceHandler = AccountPreferenceHandler(accountManager.activeAccount!!, accountManager, ::dispatchEvent)
 
                 switchPreference {
                     key = PrefKeys.MEDIA_PREVIEW_ENABLED
                     setTitle(R.string.pref_title_show_media_preview)
                     isSingleLineTitle = false
-                    preferenceDataStore = accountPreferenceHandler
+                    preferenceDataStore = accountPreferenceDataStore
                 }
 
                 switchPreference {
                     key = PrefKeys.ALWAYS_SHOW_SENSITIVE_MEDIA
                     setTitle(R.string.pref_title_alway_show_sensitive_media)
                     isSingleLineTitle = false
-                    preferenceDataStore = accountPreferenceHandler
+                    preferenceDataStore = accountPreferenceDataStore
                 }
 
                 switchPreference {
                     key = PrefKeys.ALWAYS_OPEN_SPOILER
                     setTitle(R.string.pref_title_alway_open_spoiler)
                     isSingleLineTitle = false
-                    preferenceDataStore = accountPreferenceHandler
+                    preferenceDataStore = accountPreferenceDataStore
                 }
             }
         }
@@ -353,12 +352,6 @@ class AccountPreferencesFragment : PreferenceFragmentCompat(), Injectable {
         activity?.overridePendingTransition(R.anim.slide_from_right, R.anim.slide_to_left)
     }
 
-    private fun dispatchEvent(event: PreferenceChangedEvent) {
-        lifecycleScope.launch {
-            eventHub.dispatch(event)
-        }
-    }
-
     companion object {
         fun newInstance() = AccountPreferencesFragment()
     }

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

@@ -29,6 +29,7 @@ import javax.inject.Singleton
 @Component(
     modules = [
         AppModule::class,
+        CoroutineScopeModule::class,
         NetworkModule::class,
         AndroidSupportInjectionModule::class,
         ActivitiesModule::class,

app/src/main/java/com/keylesspalace/tusky/di/CoroutineScopeModule.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.di
+
+import dagger.Module
+import dagger.Provides
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import javax.inject.Qualifier
+
+/**
+ * Scope for potentially long-running tasks that should outlive the viewmodel that
+ * started them. For example, if the API call to bookmark a status is taking a long
+ * time, that call should not be cancelled because the user has navigated away from
+ * the viewmodel that made the call.
+ *
+ * @see https://developer.android.com/topic/architecture/data-layer#make_an_operation_live_longer_than_the_screen
+ */
+@Retention(AnnotationRetention.BINARY)
+@Qualifier
+annotation class ApplicationScope
+
+@Module
+class CoroutineScopeModule {
+    @ApplicationScope
+    @Provides
+    fun providesApplicationScope() = CoroutineScope(SupervisorJob() + Dispatchers.Default)
+}

app/src/main/java/com/keylesspalace/tusky/settings/AccountPreferenceDataStore.kt

@@ -1,15 +1,21 @@
 package com.keylesspalace.tusky.settings
 
 import androidx.preference.PreferenceDataStore
+import com.keylesspalace.tusky.appstore.EventHub
 import com.keylesspalace.tusky.appstore.PreferenceChangedEvent
 import com.keylesspalace.tusky.db.AccountEntity
 import com.keylesspalace.tusky.db.AccountManager
+import com.keylesspalace.tusky.di.ApplicationScope
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
+import javax.inject.Inject
 
-class AccountPreferenceHandler(
-    private val account: AccountEntity,
+class AccountPreferenceDataStore @Inject constructor(
     private val accountManager: AccountManager,
-    private val dispatchEvent: (PreferenceChangedEvent) -> Unit
+    private val eventHub: EventHub,
+    @ApplicationScope private val externalScope: CoroutineScope
 ) : PreferenceDataStore() {
+    private val account: AccountEntity = accountManager.activeAccount!!
 
     override fun getBoolean(key: String, defValue: Boolean): Boolean {
         return when (key) {
@@ -29,6 +35,8 @@ class AccountPreferenceHandler(
 
         accountManager.saveAccount(account)
 
-        dispatchEvent(PreferenceChangedEvent(key))
+        externalScope.launch {
+            eventHub.dispatch(PreferenceChangedEvent(key))
+        }
     }
 }