Fix DiskReadViolation violations when StrictMode is enabled

example/src/main/java/com/stripe/example/ExampleApplication.kt

@@ -21,6 +21,11 @@ class ExampleApplication : MultiDexApplication() {
                 .detectDiskWrites()
                 .detectAll()
                 .penaltyLog()
+                .also {
+                    if (IS_PENALTY_DEATH_ENABLED) {
+                        it.penaltyDeath()
+                    }
+                }
                 .build()
         )
 
@@ -45,4 +50,8 @@ class ExampleApplication : MultiDexApplication() {
             false
         )
     }
+
+    private companion object {
+        private val IS_PENALTY_DEATH_ENABLED = true
+    }
 }

stripe/src/main/java/com/stripe/android/FingerprintDataStore.kt

@@ -2,20 +2,27 @@ package com.stripe.android
 
 import android.content.Context
 import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.liveData
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Dispatchers
 import org.json.JSONObject
 
 internal interface FingerprintDataStore {
     fun get(): LiveData<FingerprintData>
     fun save(fingerprintData: FingerprintData)
 
-    class Default(context: Context) : FingerprintDataStore {
-        private val prefs = context.getSharedPreferences(
-            PREF_FILE, Context.MODE_PRIVATE
-        )
+    class Default(
+        context: Context,
+        private val coroutineDispatcher: CoroutineDispatcher = Dispatchers.IO
+    ) : FingerprintDataStore {
+        private val prefs by lazy {
+            context.getSharedPreferences(
+                PREF_FILE, Context.MODE_PRIVATE
+            )
+        }
 
-        override fun get(): LiveData<FingerprintData> {
-            return MutableLiveData(
+        override fun get() = liveData<FingerprintData>(coroutineDispatcher) {
+            emit(
                 runCatching {
                     FingerprintData.fromJson(
                         JSONObject(prefs.getString(KEY_DATA, null).orEmpty())

stripe/src/main/java/com/stripe/android/PaymentSessionPrefs.kt

@@ -1,40 +1,38 @@
 package com.stripe.android
 
 import android.content.Context
+import android.content.SharedPreferences
 
 internal interface PaymentSessionPrefs {
     fun getPaymentMethodId(customerId: String?): String?
     fun savePaymentMethodId(customerId: String, paymentMethodId: String?)
 
+    class Default(context: Context) : PaymentSessionPrefs {
+        val prefs: SharedPreferences by lazy {
+            context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE)
+        }
+
+        override fun getPaymentMethodId(customerId: String?): String? {
+            return customerId?.let {
+                prefs.getString(getPaymentMethodKey(it), null)
+            }
+        }
+
+        override fun savePaymentMethodId(
+            customerId: String,
+            paymentMethodId: String?
+        ) {
+            prefs.edit()
+                .putString(getPaymentMethodKey(customerId), paymentMethodId)
+                .apply()
+        }
+    }
+
     companion object {
         private const val PREF_FILE = "PaymentSessionPrefs"
 
         private fun getPaymentMethodKey(customerId: String?): String {
             return "customer[$customerId].payment_method"
         }
-
-        @JvmSynthetic
-        internal fun create(context: Context): PaymentSessionPrefs {
-            val prefs = context.getSharedPreferences(
-                PREF_FILE, Context.MODE_PRIVATE
-            )
-            return object : PaymentSessionPrefs {
-                override fun getPaymentMethodId(customerId: String?): String? {
-                    return if (customerId != null) {
-                        prefs?.getString(getPaymentMethodKey(customerId), null)
-                    } else {
-                        null
-                    }
-                }
-
-                override fun savePaymentMethodId(
-                    customerId: String,
-                    paymentMethodId: String?
-                ) {
-                    prefs?.edit()?.putString(getPaymentMethodKey(customerId), paymentMethodId)
-                        ?.apply()
-                }
-            }
-        }
     }
 }

stripe/src/main/java/com/stripe/android/PaymentSessionViewModel.kt

@@ -18,7 +18,7 @@ internal class PaymentSessionViewModel(
     private val savedStateHandle: SavedStateHandle,
     paymentSessionData: PaymentSessionData,
     private val customerSession: CustomerSession,
-    private val paymentSessionPrefs: PaymentSessionPrefs = PaymentSessionPrefs.create(application)
+    private val paymentSessionPrefs: PaymentSessionPrefs = PaymentSessionPrefs.Default(application)
 ) : AndroidViewModel(application) {
 
     var paymentSessionData: PaymentSessionData = paymentSessionData

stripe/src/test/java/com/stripe/android/FingerprintDataRepositoryTest.kt

@@ -23,7 +23,8 @@ import org.robolectric.RobolectricTestRunner
 @ExperimentalCoroutinesApi
 class FingerprintDataRepositoryTest {
     private val context = ApplicationProvider.getApplicationContext<Context>()
-    private val testScope = TestCoroutineScope(TestCoroutineDispatcher())
+    private val testDispatcher = TestCoroutineDispatcher()
+    private val testScope = TestCoroutineScope(testDispatcher)
     private val fingerprintRequestExecutor: FingerprintRequestExecutor = mock()
 
     @AfterTest
@@ -45,7 +46,10 @@ class FingerprintDataRepositoryTest {
     fun `get() when FingerprintData is expired should request new remote FingerprintData`() {
         val expectedFingerprintData = createFingerprintData()
         val repository = FingerprintDataRepository.Default(
-            store = FingerprintDataStore.Default(context),
+            store = FingerprintDataStore.Default(
+                context,
+                testDispatcher
+            ),
             fingerprintRequestFactory = FingerprintRequestFactory(context),
             fingerprintRequestExecutor = object : FingerprintRequestExecutor {
                 override fun execute(