Clean up LocalStore initialization

This removes duplicate code from the LocalStore constructor and handleUserChange

Author: schmidt-sebastian

firebase-firestore/src/main/java/com/google/firebase/firestore/local/LocalStore.java

@@ -115,7 +115,7 @@ public final class LocalStore implements BundleCallback {
   private IndexManager indexManager;
 
   /** Manages field index backfill. */
-  private final @Nullable IndexBackfiller indexBackfiller;
+  private @Nullable IndexBackfiller indexBackfiller;
 
   /** The set of all mutations that have been sent but not yet been applied to the backend. */
   private MutationQueue mutationQueue;
@@ -158,31 +158,38 @@ public LocalStore(
     hardAssert(
         persistence.isStarted(), "LocalStore was passed an unstarted persistence implementation");
     this.persistence = persistence;
+    this.queryEngine = queryEngine;
+    this.indexBackfiller = indexBackfiller;
+
     targetCache = persistence.getTargetCache();
     bundleCache = persistence.getBundleCache();
     targetIdGenerator = TargetIdGenerator.forTargetCache(targetCache.getHighestTargetId());
-    indexManager = persistence.getIndexManager(initialUser);
-    mutationQueue = persistence.getMutationQueue(initialUser, indexManager);
-    documentOverlayCache = persistence.getDocumentOverlay(initialUser);
     remoteDocuments = persistence.getRemoteDocumentCache();
+    localViewReferences = new ReferenceSet();
+    queryDataByTarget = new SparseArray<>();
+    targetIdByTarget = new HashMap<>();
+
+    persistence.getReferenceDelegate().setInMemoryPins(localViewReferences);
+
+    initializeUserComponents(initialUser);
+  }
+
+  private void initializeUserComponents(User user) {
+    indexManager = persistence.getIndexManager(user);
+    mutationQueue = persistence.getMutationQueue(user, indexManager);
+    documentOverlayCache = persistence.getDocumentOverlay(user);
+
+    // Recreate our LocalDocumentsView using the new MutationQueue.
     localDocuments =
         new LocalDocumentsView(remoteDocuments, mutationQueue, documentOverlayCache, indexManager);
-    this.queryEngine = queryEngine;
     queryEngine.initialize(localDocuments, indexManager);
 
-    localViewReferences = new ReferenceSet();
-    persistence.getReferenceDelegate().setInMemoryPins(localViewReferences);
-
+    // TODO(indexing): Add spec tests that test these components change after a user change
     remoteDocuments.setIndexManager(indexManager);
-
-    this.indexBackfiller = indexBackfiller;
     if (indexBackfiller != null) {
       indexBackfiller.setIndexManager(indexManager);
       indexBackfiller.setLocalDocumentsView(localDocuments);
     }
-
-    queryDataByTarget = new SparseArray<>();
-    targetIdByTarget = new HashMap<>();
   }
 
   public void start() {
@@ -205,27 +212,12 @@ public ImmutableSortedMap<DocumentKey, Document> handleUserChange(User user) {
     // Swap out the mutation queue, grabbing the pending mutation batches before and after.
     List<MutationBatch> oldBatches = mutationQueue.getAllMutationBatches();
 
-    indexManager = persistence.getIndexManager(user);
-    mutationQueue = persistence.getMutationQueue(user, indexManager);
-    documentOverlayCache = persistence.getDocumentOverlay(user);
-
+    initializeUserComponents(user);
     startIndexManager();
     startMutationQueue();
 
     List<MutationBatch> newBatches = mutationQueue.getAllMutationBatches();
 
-    // Recreate our LocalDocumentsView using the new MutationQueue.
-    localDocuments =
-        new LocalDocumentsView(remoteDocuments, mutationQueue, documentOverlayCache, indexManager);
-    queryEngine.initialize(localDocuments, indexManager);
-
-    // TODO(indexing): Add spec tests that test these components change after a user change
-    remoteDocuments.setIndexManager(indexManager);
-    if (indexBackfiller != null) {
-      indexBackfiller.setIndexManager(indexManager);
-      indexBackfiller.setLocalDocumentsView(localDocuments);
-    }
-
     // Union the old/new changed keys.
     ImmutableSortedSet<DocumentKey> changedKeys = DocumentKey.emptyKeySet();
     for (List<MutationBatch> batches : asList(oldBatches, newBatches)) {