Simplify settings package and a few more classes using DI (#6778)

Simplify settings package and a few more classes using DI.

The biggest example is `SessionsSettings`, which used to have multiple
secondary constructors. This
change lets us avoid plumbing dependencies like `DataStore<>` through
multiple classes.

Moved DataStore construction into provides, which will be needed for
`MultiProcessDataStoreFactory`.

Also cleaned up tests a bit. We shouldn't use Dagger in the unit tests
on Android. Once we remove
the bound service, it will be easy to remove DI from the unit tests.
Instead, unit tests will just
call the constructors directly and pass in real or fake instances.

Author: mrober

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/FirebaseSessionsComponent.kt

@@ -17,22 +17,48 @@
 package com.google.firebase.sessions
 
 import android.content.Context
+import android.util.Log
+import androidx.datastore.core.DataStore
+import androidx.datastore.core.handlers.ReplaceFileCorruptionHandler
+import androidx.datastore.preferences.core.PreferenceDataStoreFactory
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.emptyPreferences
+import androidx.datastore.preferences.preferencesDataStoreFile
 import com.google.android.datatransport.TransportFactory
 import com.google.firebase.FirebaseApp
 import com.google.firebase.annotations.concurrent.Background
 import com.google.firebase.annotations.concurrent.Blocking
 import com.google.firebase.inject.Provider
 import com.google.firebase.installations.FirebaseInstallationsApi
+import com.google.firebase.sessions.ProcessDetailsProvider.getProcessName
+import com.google.firebase.sessions.settings.CrashlyticsSettingsFetcher
+import com.google.firebase.sessions.settings.LocalOverrideSettings
+import com.google.firebase.sessions.settings.RemoteSettings
+import com.google.firebase.sessions.settings.RemoteSettingsFetcher
 import com.google.firebase.sessions.settings.SessionsSettings
+import com.google.firebase.sessions.settings.SettingsProvider
 import dagger.Binds
 import dagger.BindsInstance
 import dagger.Component
 import dagger.Module
 import dagger.Provides
+import javax.inject.Qualifier
 import javax.inject.Singleton
 import kotlin.coroutines.CoroutineContext
 
-/** Dagger component to provide [FirebaseSessions] and its dependencies. */
+@Qualifier internal annotation class SessionConfigsDataStore
+
+@Qualifier internal annotation class SessionDetailsDataStore
+
+@Qualifier internal annotation class LocalOverrideSettingsProvider
+
+@Qualifier internal annotation class RemoteSettingsProvider
+
+/**
+ * Dagger component to provide [FirebaseSessions] and its dependencies.
+ *
+ * This gets configured and built in [FirebaseSessionsRegistrar.getComponents].
+ */
 @Singleton
 @Component(modules = [FirebaseSessionsComponent.MainModule::class])
 internal interface FirebaseSessionsComponent {
@@ -79,8 +105,59 @@ internal interface FirebaseSessionsComponent {
       impl: SessionLifecycleServiceBinderImpl
     ): SessionLifecycleServiceBinder
 
+    @Binds
+    @Singleton
+    fun crashlyticsSettingsFetcher(impl: RemoteSettingsFetcher): CrashlyticsSettingsFetcher
+
+    @Binds
+    @Singleton
+    @LocalOverrideSettingsProvider
+    fun localOverrideSettings(impl: LocalOverrideSettings): SettingsProvider
+
+    @Binds
+    @Singleton
+    @RemoteSettingsProvider
+    fun remoteSettings(impl: RemoteSettings): SettingsProvider
+
     companion object {
-      @Provides @Singleton fun sessionGenerator() = SessionGenerator(timeProvider = WallClock)
+      private const val TAG = "FirebaseSessions"
+
+      @Provides @Singleton fun timeProvider(): TimeProvider = TimeProviderImpl
+
+      @Provides @Singleton fun uuidGenerator(): UuidGenerator = UuidGeneratorImpl
+
+      @Provides
+      @Singleton
+      fun applicationInfo(firebaseApp: FirebaseApp): ApplicationInfo =
+        SessionEvents.getApplicationInfo(firebaseApp)
+
+      @Provides
+      @Singleton
+      @SessionConfigsDataStore
+      fun sessionConfigsDataStore(appContext: Context): DataStore<Preferences> =
+        PreferenceDataStoreFactory.create(
+          corruptionHandler =
+            ReplaceFileCorruptionHandler { ex ->
+              Log.w(TAG, "CorruptionException in settings DataStore in ${getProcessName()}.", ex)
+              emptyPreferences()
+            }
+        ) {
+          appContext.preferencesDataStoreFile(SessionDataStoreConfigs.SETTINGS_CONFIG_NAME)
+        }
+
+      @Provides
+      @Singleton
+      @SessionDetailsDataStore
+      fun sessionDetailsDataStore(appContext: Context): DataStore<Preferences> =
+        PreferenceDataStoreFactory.create(
+          corruptionHandler =
+            ReplaceFileCorruptionHandler { ex ->
+              Log.w(TAG, "CorruptionException in sessions DataStore in ${getProcessName()}.", ex)
+              emptyPreferences()
+            }
+        ) {
+          appContext.preferencesDataStoreFile(SessionDataStoreConfigs.SESSIONS_CONFIG_NAME)
+        }
     }
   }
 }

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/SessionDatastore.kt

@@ -16,19 +16,15 @@
 
 package com.google.firebase.sessions
 
-import android.content.Context
 import android.util.Log
 import androidx.datastore.core.DataStore
-import androidx.datastore.core.handlers.ReplaceFileCorruptionHandler
 import androidx.datastore.preferences.core.Preferences
 import androidx.datastore.preferences.core.edit
 import androidx.datastore.preferences.core.emptyPreferences
 import androidx.datastore.preferences.core.stringPreferencesKey
-import androidx.datastore.preferences.preferencesDataStore
 import com.google.firebase.Firebase
 import com.google.firebase.annotations.concurrent.Background
 import com.google.firebase.app
-import com.google.firebase.sessions.ProcessDetailsProvider.getProcessName
 import java.io.IOException
 import java.util.concurrent.atomic.AtomicReference
 import javax.inject.Inject
@@ -64,8 +60,8 @@ internal interface SessionDatastore {
 internal class SessionDatastoreImpl
 @Inject
 constructor(
-  private val appContext: Context,
   @Background private val backgroundDispatcher: CoroutineContext,
+  @SessionDetailsDataStore private val dataStore: DataStore<Preferences>,
 ) : SessionDatastore {
 
   /** Most recent session from datastore is updated asynchronously whenever it changes */
@@ -76,7 +72,7 @@ constructor(
   }
 
   private val firebaseSessionDataFlow: Flow<FirebaseSessionsData> =
-    appContext.dataStore.data
+    dataStore.data
       .catch { exception ->
         Log.e(TAG, "Error reading stored session data.", exception)
         emit(emptyPreferences())
@@ -92,7 +88,7 @@ constructor(
   override fun updateSessionId(sessionId: String) {
     CoroutineScope(backgroundDispatcher).launch {
       try {
-        appContext.dataStore.edit { preferences ->
+        dataStore.edit { preferences ->
           preferences[FirebaseSessionDataKeys.SESSION_ID] = sessionId
         }
       } catch (e: IOException) {
@@ -108,15 +104,5 @@ constructor(
 
   private companion object {
     private const val TAG = "FirebaseSessionsRepo"
-
-    private val Context.dataStore: DataStore<Preferences> by
-      preferencesDataStore(
-        name = SessionDataStoreConfigs.SESSIONS_CONFIG_NAME,
-        corruptionHandler =
-          ReplaceFileCorruptionHandler { ex ->
-            Log.w(TAG, "CorruptionException in sessions DataStore in ${getProcessName()}.", ex)
-            emptyPreferences()
-          },
-      )
   }
 }

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/SessionGenerator.kt

@@ -19,7 +19,7 @@ package com.google.firebase.sessions
 import com.google.errorprone.annotations.CanIgnoreReturnValue
 import com.google.firebase.Firebase
 import com.google.firebase.app
-import java.util.UUID
+import javax.inject.Inject
 import javax.inject.Singleton
 
 /**
@@ -37,10 +37,9 @@ internal data class SessionDetails(
  * [SessionDetails] up to date with the latest values.
  */
 @Singleton
-internal class SessionGenerator(
-  private val timeProvider: TimeProvider,
-  private val uuidGenerator: () -> UUID = UUID::randomUUID,
-) {
+internal class SessionGenerator
+@Inject
+constructor(private val timeProvider: TimeProvider, private val uuidGenerator: UuidGenerator) {
   private val firstSessionId = generateSessionId()
   private var sessionIndex = -1
 
@@ -66,7 +65,7 @@ internal class SessionGenerator(
     return currentSession
   }
 
-  private fun generateSessionId() = uuidGenerator().toString().replace("-", "").lowercase()
+  private fun generateSessionId() = uuidGenerator.next().toString().replace("-", "").lowercase()
 
   internal companion object {
     val instance: SessionGenerator

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/TimeProvider.kt

@@ -23,11 +23,12 @@ import kotlin.time.Duration.Companion.milliseconds
 /** Time provider interface, for testing purposes. */
 internal interface TimeProvider {
   fun elapsedRealtime(): Duration
+
   fun currentTimeUs(): Long
 }
 
-/** "Wall clock" time provider. */
-internal object WallClock : TimeProvider {
+/** "Wall clock" time provider implementation. */
+internal object TimeProviderImpl : TimeProvider {
   /**
    * Gets the [Duration] elapsed in "wall clock" time since device boot.
    *

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/UuidGenerator.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.sessions
+
+import java.util.UUID
+
+/** UUID generator interface. */
+internal fun interface UuidGenerator {
+  fun next(): UUID
+}
+
+/** Generate random UUIDs using [UUID.randomUUID]. */
+internal object UuidGeneratorImpl : UuidGenerator {
+  override fun next(): UUID = UUID.randomUUID()
+}

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/settings/LocalOverrideSettings.kt

@@ -19,20 +19,19 @@ package com.google.firebase.sessions.settings
 import android.content.Context
 import android.content.pm.PackageManager
 import android.os.Bundle
+import javax.inject.Inject
+import javax.inject.Singleton
 import kotlin.time.Duration
 import kotlin.time.DurationUnit
 import kotlin.time.toDuration
 
-internal class LocalOverrideSettings(context: Context) : SettingsProvider {
-  @Suppress("DEPRECATION") // TODO(mrober): Use ApplicationInfoFlags when target sdk set to 33
+@Singleton
+internal class LocalOverrideSettings @Inject constructor(appContext: Context) : SettingsProvider {
   private val metadata =
-    context.packageManager
-      .getApplicationInfo(
-        context.packageName,
-        PackageManager.GET_META_DATA,
-      )
+    appContext.packageManager
+      .getApplicationInfo(appContext.packageName, PackageManager.GET_META_DATA)
       .metaData
-      ?: Bundle.EMPTY // Default to an empty bundle, meaning no cached values.
+      ?: Bundle.EMPTY // Default to an empty bundle
 
   override val sessionEnabled: Boolean?
     get() =

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/settings/RemoteSettings.kt

@@ -19,11 +19,13 @@ package com.google.firebase.sessions.settings
 import android.os.Build
 import android.util.Log
 import androidx.annotation.VisibleForTesting
-import androidx.datastore.core.DataStore
-import androidx.datastore.preferences.core.Preferences
+import com.google.firebase.annotations.concurrent.Background
 import com.google.firebase.installations.FirebaseInstallationsApi
 import com.google.firebase.sessions.ApplicationInfo
 import com.google.firebase.sessions.InstallationId
+import dagger.Lazy
+import javax.inject.Inject
+import javax.inject.Singleton
 import kotlin.coroutines.CoroutineContext
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.seconds
@@ -34,14 +36,19 @@ import kotlinx.coroutines.sync.withLock
 import org.json.JSONException
 import org.json.JSONObject
 
-internal class RemoteSettings(
-  private val backgroundDispatcher: CoroutineContext,
+@Singleton
+internal class RemoteSettings
+@Inject
+constructor(
+  @Background private val backgroundDispatcher: CoroutineContext,
   private val firebaseInstallationsApi: FirebaseInstallationsApi,
   private val appInfo: ApplicationInfo,
   private val configsFetcher: CrashlyticsSettingsFetcher,
-  dataStore: DataStore<Preferences>,
+  private val lazySettingsCache: Lazy<SettingsCache>,
 ) : SettingsProvider {
-  private val settingsCache by lazy { SettingsCache(dataStore) }
+  private val settingsCache: SettingsCache
+    get() = lazySettingsCache.get()
+
   private val fetchInProgress = Mutex()
 
   override val sessionEnabled: Boolean?

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/settings/RemoteSettingsFetcher.kt

@@ -17,10 +17,13 @@
 package com.google.firebase.sessions.settings
 
 import android.net.Uri
+import com.google.firebase.annotations.concurrent.Background
 import com.google.firebase.sessions.ApplicationInfo
 import java.io.BufferedReader
 import java.io.InputStreamReader
 import java.net.URL
+import javax.inject.Inject
+import javax.inject.Singleton
 import javax.net.ssl.HttpsURLConnection
 import kotlin.coroutines.CoroutineContext
 import kotlinx.coroutines.withContext
@@ -30,20 +33,22 @@ internal fun interface CrashlyticsSettingsFetcher {
   suspend fun doConfigFetch(
     headerOptions: Map<String, String>,
     onSuccess: suspend (JSONObject) -> Unit,
-    onFailure: suspend (msg: String) -> Unit
+    onFailure: suspend (msg: String) -> Unit,
   )
 }
 
-internal class RemoteSettingsFetcher(
+@Singleton
+internal class RemoteSettingsFetcher
+@Inject
+constructor(
   private val appInfo: ApplicationInfo,
-  private val blockingDispatcher: CoroutineContext,
-  private val baseUrl: String = FIREBASE_SESSIONS_BASE_URL_STRING,
+  @Background private val blockingDispatcher: CoroutineContext,
 ) : CrashlyticsSettingsFetcher {
   @Suppress("BlockingMethodInNonBlockingContext") // blockingDispatcher is safe for blocking calls.
   override suspend fun doConfigFetch(
     headerOptions: Map<String, String>,
     onSuccess: suspend (JSONObject) -> Unit,
-    onFailure: suspend (String) -> Unit
+    onFailure: suspend (String) -> Unit,
   ) =
     withContext(blockingDispatcher) {
       try {
@@ -78,7 +83,7 @@ internal class RemoteSettingsFetcher(
     val uri =
       Uri.Builder()
         .scheme("https")
-        .authority(baseUrl)
+        .authority(FIREBASE_SESSIONS_BASE_URL_STRING)
         .appendPath("spi")
         .appendPath("v2")
         .appendPath("platforms")