Attempt to fix ANRs by moving some tasks during configure to backgrou…

…nd (#1772)

## Description
This PR addresses a significant number of ANRs (Application Not
Responding errors) reported, such as in issue #1629.

## Problem
The method `IdentityManager.configure` is currently running on the main
thread and accessing `SharedPreferences`. Accessing `SharedPreferences`
can be costly, especially if the XML file storing the preferences is
large. This cost is particularly high during the initial accesses, as
the XML file needs to be read and parsed, which can block the main
thread and lead to ANRs.

## Solution
**Custom Dispatcher**: This PR introduces a custom dispatcher to the
`IdentityManager`, allowing configure to run on a background thread. By
moving this operation off the main thread, we avoid blocking it with the
potentially expensive SharedPreferences access.
**Main Thread Optimization**: The remaining setup in
`PurchasesOrchestrator` has been deferred to execute after configure
completes, ensuring the main thread remains unblocked and improving
overall app responsiveness.

## Notes
While this fix should mitigate the reported ANRs, it's possible there
are other underlying causes contributing to these issues. This PR serves
as a good initial step towards improving performance.

purchases/src/main/kotlin/com/revenuecat/purchases/PurchasesFactory.kt

@@ -179,6 +179,7 @@ internal class PurchasesFactory(
                 offeringsCache,
                 backend,
                 offlineEntitlementsManager,
+                dispatcher,
             )
 
             val customerInfoUpdateHandler = CustomerInfoUpdateHandler(
@@ -285,6 +286,7 @@ internal class PurchasesFactory(
                 createPaywallEventsManager(application, identityManager, eventsDispatcher, backend),
                 paywallPresentedCache,
                 purchasesStateProvider,
+                dispatcher = dispatcher,
             )
 
             return Purchases(purchasesOrchestrator)

purchases/src/main/kotlin/com/revenuecat/purchases/PurchasesOrchestrator.kt

@@ -16,6 +16,8 @@ import com.revenuecat.purchases.common.Backend
 import com.revenuecat.purchases.common.BillingAbstract
 import com.revenuecat.purchases.common.Config
 import com.revenuecat.purchases.common.Constants
+import com.revenuecat.purchases.common.Delay
+import com.revenuecat.purchases.common.Dispatcher
 import com.revenuecat.purchases.common.LogIntent
 import com.revenuecat.purchases.common.PlatformInfo
 import com.revenuecat.purchases.common.ReceiptInfo
@@ -73,7 +75,7 @@ import java.util.concurrent.atomic.AtomicBoolean
 import kotlin.time.Duration.Companion.seconds
 
 @Suppress("LongParameterList", "LargeClass", "TooManyFunctions")
-internal class PurchasesOrchestrator constructor(
+internal class PurchasesOrchestrator(
     private val application: Application,
     backingFieldAppUserID: String?,
     private val backend: Backend,
@@ -97,6 +99,7 @@ internal class PurchasesOrchestrator constructor(
     private val purchasesStateCache: PurchasesStateCache,
     // This is nullable due to: https://github.com/RevenueCat/purchases-flutter/issues/408
     private val mainHandler: Handler? = Handler(Looper.getMainLooper()),
+    private val dispatcher: Dispatcher,
 ) : LifecycleDelegate, CustomActivityLifecycleHandler {
 
     internal var state: PurchasesState
@@ -194,22 +197,24 @@ internal class PurchasesOrchestrator constructor(
             state = state.copy(appInBackground = false, firstTimeInForeground = false)
         }
         log(LogIntent.DEBUG, ConfigureStrings.APP_FOREGROUNDED)
-        if (shouldRefreshCustomerInfo(firstTimeInForeground)) {
-            log(LogIntent.DEBUG, CustomerInfoStrings.CUSTOMERINFO_STALE_UPDATING_FOREGROUND)
-            customerInfoHelper.retrieveCustomerInfo(
-                identityManager.currentAppUserID,
-                fetchPolicy = CacheFetchPolicy.FETCH_CURRENT,
-                appInBackground = false,
-                allowSharingPlayStoreAccount = allowSharingPlayStoreAccount,
-            )
-        }
-        offeringsManager.onAppForeground(identityManager.currentAppUserID)
-        postPendingTransactionsHelper.syncPendingPurchaseQueue(allowSharingPlayStoreAccount)
-        synchronizeSubscriberAttributesIfNeeded()
-        offlineEntitlementsManager.updateProductEntitlementMappingCacheIfStale()
-        flushPaywallEvents()
-        if (firstTimeInForeground && isAndroidNOrNewer()) {
-            diagnosticsSynchronizer?.syncDiagnosticsFileIfNeeded()
+        enqueue {
+            if (shouldRefreshCustomerInfo(firstTimeInForeground)) {
+                log(LogIntent.DEBUG, CustomerInfoStrings.CUSTOMERINFO_STALE_UPDATING_FOREGROUND)
+                customerInfoHelper.retrieveCustomerInfo(
+                    identityManager.currentAppUserID,
+                    fetchPolicy = CacheFetchPolicy.FETCH_CURRENT,
+                    appInBackground = false,
+                    allowSharingPlayStoreAccount = allowSharingPlayStoreAccount,
+                )
+            }
+            offeringsManager.onAppForeground(identityManager.currentAppUserID)
+            postPendingTransactionsHelper.syncPendingPurchaseQueue(allowSharingPlayStoreAccount)
+            synchronizeSubscriberAttributesIfNeeded()
+            offlineEntitlementsManager.updateProductEntitlementMappingCacheIfStale()
+            flushPaywallEvents()
+            if (firstTimeInForeground && isAndroidNOrNewer()) {
+                diagnosticsSynchronizer?.syncDiagnosticsFileIfNeeded()
+            }
         }
     }
 
@@ -775,6 +780,9 @@ internal class PurchasesOrchestrator constructor(
     //endregion
 
     // region Private Methods
+    private fun enqueue(command: () -> Unit) {
+        dispatcher.enqueue({ command() }, Delay.NONE)
+    }
 
     private fun shouldRefreshCustomerInfo(firstTimeInForeground: Boolean): Boolean {
         return !appConfig.customEntitlementComputation &&

purchases/src/main/kotlin/com/revenuecat/purchases/common/caching/DeviceCache.kt

@@ -64,6 +64,10 @@ internal open class DeviceCache(
 
     private val offeringsResponseCacheKey: String by lazy { "$apiKeyPrefix.offeringsResponse" }
 
+    fun startEditing(): SharedPreferences.Editor {
+        return preferences.edit()
+    }
+
     // region app user id
 
     @Synchronized
@@ -74,7 +78,15 @@ internal open class DeviceCache(
 
     @Synchronized
     fun cacheAppUserID(appUserID: String) {
-        preferences.edit().putString(appUserIDCacheKey, appUserID).apply()
+        cacheAppUserID(appUserID, preferences.edit()).apply()
+    }
+
+    @Synchronized
+    fun cacheAppUserID(
+        appUserID: String,
+        cacheEditor: SharedPreferences.Editor,
+    ): SharedPreferences.Editor {
+        return cacheEditor.putString(appUserIDCacheKey, appUserID)
     }
 
     @Synchronized
@@ -168,9 +180,17 @@ internal open class DeviceCache(
     @Synchronized
     fun clearCustomerInfoCache(appUserID: String) {
         val editor = preferences.edit()
+        clearCustomerInfoCache(appUserID, editor)
+        editor.apply()
+    }
+
+    @Synchronized
+    fun clearCustomerInfoCache(
+        appUserID: String,
+        editor: SharedPreferences.Editor,
+    ) {
         editor.clearCustomerInfoCacheTimestamp(appUserID)
         editor.remove(customerInfoCacheKey(appUserID))
-        editor.apply()
     }
 
     @Synchronized

purchases/src/main/kotlin/com/revenuecat/purchases/identity/IdentityManager.kt

@@ -1,10 +1,13 @@
 package com.revenuecat.purchases.identity
 
+import android.content.SharedPreferences
 import com.revenuecat.purchases.CustomerInfo
 import com.revenuecat.purchases.PurchasesError
 import com.revenuecat.purchases.PurchasesErrorCode
 import com.revenuecat.purchases.VerificationResult
 import com.revenuecat.purchases.common.Backend
+import com.revenuecat.purchases.common.Delay
+import com.revenuecat.purchases.common.Dispatcher
 import com.revenuecat.purchases.common.LogIntent
 import com.revenuecat.purchases.common.caching.DeviceCache
 import com.revenuecat.purchases.common.debugLog
@@ -20,14 +23,15 @@ import com.revenuecat.purchases.subscriberattributes.caching.SubscriberAttribute
 import java.util.Locale
 import java.util.UUID
 
-@Suppress("TooManyFunctions")
+@Suppress("TooManyFunctions", "LongParameterList")
 internal class IdentityManager(
     private val deviceCache: DeviceCache,
     private val subscriberAttributesCache: SubscriberAttributesCache,
     private val subscriberAttributesManager: SubscriberAttributesManager,
     private val offeringsCache: OfferingsCache,
     private val backend: Backend,
     private val offlineEntitlementsManager: OfflineEntitlementsManager,
+    private val dispatcher: Dispatcher,
 ) {
 
     val currentAppUserID: String
@@ -38,7 +42,9 @@ internal class IdentityManager(
     // region Public functions
 
     @Synchronized
-    fun configure(appUserID: String?) {
+    fun configure(
+        appUserID: String?,
+    ) {
         if (appUserID?.isBlank() == true) {
             log(LogIntent.WARNING, IdentityStrings.EMPTY_APP_USER_ID_WILL_BECOME_ANONYMOUS)
         }
@@ -49,10 +55,16 @@ internal class IdentityManager(
             ?: deviceCache.getLegacyCachedAppUserID()
             ?: generateRandomID()
         log(LogIntent.USER, IdentityStrings.IDENTIFYING_APP_USER_ID.format(appUserIDToUse))
-        deviceCache.cacheAppUserID(appUserIDToUse)
-        subscriberAttributesCache.cleanUpSubscriberAttributeCache(appUserIDToUse)
-        deviceCache.cleanupOldAttributionData()
-        invalidateCustomerInfoAndETagCacheIfNeeded(appUserIDToUse)
+
+        val cacheEditor = deviceCache.startEditing()
+        deviceCache.cacheAppUserID(appUserIDToUse, cacheEditor)
+        subscriberAttributesCache.cleanUpSubscriberAttributeCache(appUserIDToUse, cacheEditor)
+        invalidateCustomerInfoAndETagCacheIfNeeded(appUserIDToUse, cacheEditor)
+        cacheEditor.apply()
+
+        enqueue {
+            deviceCache.cleanupOldAttributionData()
+        }
     }
 
     fun logIn(
@@ -135,11 +147,17 @@ internal class IdentityManager(
         }
     }
 
-    private fun invalidateCustomerInfoAndETagCacheIfNeeded(appUserID: String) {
+    private fun invalidateCustomerInfoAndETagCacheIfNeeded(
+        appUserID: String,
+        cacheEditor: SharedPreferences.Editor,
+    ) {
+        if (backend.verificationMode == SignatureVerificationMode.Disabled) {
+            return
+        }
         val cachedCustomerInfo = deviceCache.getCachedCustomerInfo(appUserID)
         if (shouldInvalidateCustomerInfoAndETagCache(cachedCustomerInfo)) {
             infoLog(IdentityStrings.INVALIDATING_CACHED_CUSTOMER_INFO)
-            deviceCache.clearCustomerInfoCache(appUserID)
+            deviceCache.clearCustomerInfoCache(appUserID, cacheEditor)
             backend.clearCaches()
         }
     }
@@ -172,5 +190,10 @@ internal class IdentityManager(
         backend.clearCaches()
     }
 
+    @Synchronized
+    private fun enqueue(command: () -> Unit) {
+        dispatcher.enqueue({ command() }, Delay.NONE)
+    }
+
     // endregion
 }

purchases/src/main/kotlin/com/revenuecat/purchases/subscriberattributes/caching/SubscriberAttributesCache.kt

@@ -5,6 +5,7 @@
 
 package com.revenuecat.purchases.subscriberattributes.caching
 
+import android.content.SharedPreferences
 import com.revenuecat.purchases.common.LogIntent
 import com.revenuecat.purchases.common.caching.DeviceCache
 import com.revenuecat.purchases.common.log
@@ -76,12 +77,15 @@ internal class SubscriberAttributesCache(
     }
 
     @Synchronized
-    fun cleanUpSubscriberAttributeCache(currentAppUserID: String) {
-        migrateSubscriberAttributesIfNeeded()
-        deleteSyncedSubscriberAttributesForOtherUsers(currentAppUserID)
+    fun cleanUpSubscriberAttributeCache(
+        currentAppUserID: String,
+        cacheEditor: SharedPreferences.Editor,
+    ) {
+        migrateSubscriberAttributesIfNeeded(cacheEditor)
+        deleteSyncedSubscriberAttributesForOtherUsers(currentAppUserID, cacheEditor)
     }
 
-    internal fun DeviceCache.putAttributes(
+    private fun DeviceCache.putAttributes(
         updatedSubscriberAttributesForAll: SubscriberAttributesPerAppUserIDMap,
     ) {
         return deviceCache.putString(
@@ -91,7 +95,10 @@ internal class SubscriberAttributesCache(
     }
 
     @Synchronized
-    private fun deleteSyncedSubscriberAttributesForOtherUsers(currentAppUserID: String) {
+    private fun deleteSyncedSubscriberAttributesForOtherUsers(
+        currentAppUserID: String,
+        cacheEditor: SharedPreferences.Editor,
+    ) {
         log(LogIntent.DEBUG, AttributionStrings.DELETING_ATTRIBUTES_OTHER_USERS.format(currentAppUserID))
 
         val allStoredSubscriberAttributes = getAllStoredSubscriberAttributes()
@@ -105,7 +112,10 @@ internal class SubscriberAttributesCache(
                 }
             }.toMap().filterValues { it.isNotEmpty() }
 
-        deviceCache.putAttributes(filteredMap)
+        cacheEditor.putString(
+            subscriberAttributesCacheKey,
+            filteredMap.toJSONObject().toString(),
+        )
     }
 
     private fun SubscriberAttributeMap.filterUnsynced(appUserID: AppUserID): SubscriberAttributeMap =

purchases/src/main/kotlin/com/revenuecat/purchases/subscriberattributes/caching/SubscriberAttributesMigrationExtensions.kt

@@ -1,19 +1,21 @@
 package com.revenuecat.purchases.subscriberattributes.caching
 
+import android.content.SharedPreferences
 import com.revenuecat.purchases.subscriberattributes.buildLegacySubscriberAttributes
 
 @Synchronized
-internal fun SubscriberAttributesCache.migrateSubscriberAttributesIfNeeded() {
+internal fun SubscriberAttributesCache.migrateSubscriberAttributesIfNeeded(cacheEditor: SharedPreferences.Editor) {
     getAllLegacyStoredSubscriberAttributes()
         .takeIf { it.isNotEmpty() }
         ?.let { legacySubscriberAttributes ->
-            migrateSubscriberAttributes(legacySubscriberAttributes)
+            migrateSubscriberAttributes(legacySubscriberAttributes, cacheEditor)
         }
 }
 
 @Synchronized
 internal fun SubscriberAttributesCache.migrateSubscriberAttributes(
     legacySubscriberAttributesForAppUserID: SubscriberAttributesPerAppUserIDMap,
+    cacheEditor: SharedPreferences.Editor,
 ) {
     val storedSubscriberAttributesForAll: SubscriberAttributesPerAppUserIDMap =
         getAllStoredSubscriberAttributes()
@@ -25,10 +27,13 @@ internal fun SubscriberAttributesCache.migrateSubscriberAttributes(
         val current: SubscriberAttributeMap = storedSubscriberAttributesForAll[appUserID] ?: emptyMap()
         val updated: SubscriberAttributeMap = legacy + current
         updatedStoredSubscriberAttributesForAll[appUserID] = updated
-        deviceCache.remove(legacySubscriberAttributesCacheKey(appUserID))
+        cacheEditor.remove(legacySubscriberAttributesCacheKey(appUserID))
     }
 
-    deviceCache.putAttributes(updatedStoredSubscriberAttributesForAll)
+    cacheEditor.putString(
+        subscriberAttributesCacheKey,
+        updatedStoredSubscriberAttributesForAll.toJSONObject().toString(),
+    )
 }
 
 internal fun SubscriberAttributesCache.legacySubscriberAttributesCacheKey(appUserID: String) =
@@ -39,12 +44,12 @@ internal fun SubscriberAttributesCache.getAllLegacyStoredSubscriberAttributes():
     val legacySubscriberAttributesCacheKeyPrefix = legacySubscriberAttributesCacheKey("")
     val allSubscriberAttributesKeys = deviceCache.findKeysThatStartWith(legacySubscriberAttributesCacheKeyPrefix)
 
-    return allSubscriberAttributesKeys.map { preferencesKey ->
+    return allSubscriberAttributesKeys.associate { preferencesKey ->
         val appUserIDFromKey: AppUserID =
             preferencesKey.split(legacySubscriberAttributesCacheKeyPrefix)[1]
         val subscriberAttributeMap: SubscriberAttributeMap =
             deviceCache.getJSONObjectOrNull(preferencesKey)
                 ?.buildLegacySubscriberAttributes() ?: emptyMap()
         appUserIDFromKey to subscriberAttributeMap
-    }.toMap()
+    }
 }

purchases/src/test/java/com/revenuecat/purchases/BasePurchasesTest.kt

@@ -33,6 +33,7 @@ import com.revenuecat.purchases.paywalls.PaywallPresentedCache
 import com.revenuecat.purchases.paywalls.events.PaywallEventsManager
 import com.revenuecat.purchases.subscriberattributes.SubscriberAttributesManager
 import com.revenuecat.purchases.utils.STUB_PRODUCT_IDENTIFIER
+import com.revenuecat.purchases.utils.SyncDispatcher
 import com.revenuecat.purchases.utils.createMockOneTimeProductDetails
 import com.revenuecat.purchases.utils.stubGooglePurchase
 import com.revenuecat.purchases.utils.stubPurchaseHistoryRecord
@@ -406,6 +407,7 @@ internal open class BasePurchasesTest {
             paywallEventsManager = mockPaywallEventsManager,
             paywallPresentedCache = paywallPresentedCache,
             purchasesStateCache = purchasesStateProvider,
+            dispatcher = SyncDispatcher(),
         )
         purchases = Purchases(purchasesOrchestrator)
         Purchases.sharedInstance = purchases