DataConnectCredentialsTokenManager.kt: use MutableStateFlow instead of AtomicReference

Author: dconeybe

firebase-dataconnect/src/main/kotlin/com/google/firebase/dataconnect/core/DataConnectCredentialsTokenManager.kt

@@ -30,7 +30,6 @@ import com.google.firebase.inject.Provider
 import com.google.firebase.internal.api.FirebaseNoSignedInUserException
 import com.google.firebase.util.nextAlphanumericString
 import java.lang.ref.WeakReference
-import java.util.concurrent.atomic.AtomicReference
 import kotlin.coroutines.coroutineContext
 import kotlin.random.Random
 import kotlinx.coroutines.CancellationException
@@ -129,7 +128,7 @@ internal sealed class DataConnectCredentialsTokenManager<T : Any>(
    * coroutines to run on the thread.
    */
   private val state =
-    AtomicReference<State<T>>(State.Idle(provider = null, forceTokenRefresh = false))
+    MutableStateFlow<State<T>>(State.Idle(provider = null, forceTokenRefresh = false))
 
   /**
    * Adds the token listener to the given provider.
@@ -171,7 +170,7 @@ internal sealed class DataConnectCredentialsTokenManager<T : Any>(
   // This function must ONLY be called from close().
   private fun setClosedState() {
     while (true) {
-      val oldState = state.get()
+      val oldState = state.value
       val providerProvider: ProviderProvider<T> =
         when (oldState) {
           is State.Closed -> return
@@ -194,7 +193,7 @@ internal sealed class DataConnectCredentialsTokenManager<T : Any>(
   suspend fun forceRefresh() {
     logger.debug { "forceRefresh()" }
     while (true) {
-      val oldState = state.get()
+      val oldState = state.value
       val oldStateProviderProvider =
         when (oldState) {
           is State.Closed -> return
@@ -246,7 +245,7 @@ internal sealed class DataConnectCredentialsTokenManager<T : Any>(
     logger.debug { "$invocationId getToken(requestId=$requestId)" }
     while (true) {
       val attemptSequenceNumber = nextSequenceNumber()
-      val oldState = state.get()
+      val oldState = state.value
 
       val newState: State.Active<T> =
         when (oldState) {
@@ -342,7 +341,7 @@ internal sealed class DataConnectCredentialsTokenManager<T : Any>(
     addTokenListener(newProvider)
 
     while (true) {
-      val oldState = state.get()
+      val oldState = state.value
       val newState =
         when (oldState) {
           is State.Closed -> {