Don't leak orphaned docs when deleting (firebase#32)

Don't leak orphaned docs when deleting in memory lru reference delegate

Author: Greg Soltis

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

@@ -18,6 +18,7 @@
 
 import com.google.firebase.firestore.core.ListenSequence;
 import com.google.firebase.firestore.model.DocumentKey;
+import com.google.firebase.firestore.model.MaybeDocument;
 import com.google.firebase.firestore.util.Consumer;
 import java.util.HashMap;
 import java.util.Map;
@@ -99,7 +100,17 @@ public int removeTargets(long upperBound, Set<Integer> activeTargetIds) {
 
  @Override
  public int removeOrphanedDocuments(long upperBound) {
- return persistence.getRemoteDocumentCache().removeOrphanedDocuments(this, upperBound);
+ int count = 0;
+ MemoryRemoteDocumentCache cache = persistence.getRemoteDocumentCache();
+ for (Map.Entry<DocumentKey, MaybeDocument> entry : cache.getDocuments()) {
+ DocumentKey key = entry.getKey();
+ if (!isPinned(key, upperBound)) {
+ cache.remove(key);
+ orphanedSequenceNumbers.remove(key);
+ count++;
+ }
+ }
+ return count;
  }
 
  @Override
@@ -139,7 +150,11 @@ private boolean mutationQueuesContainsKey(DocumentKey key) {
  return false;
  }
 
- public boolean isPinned(DocumentKey key, long upperBound) {
+ /**
+ * @return true if there is anything that would keep the given document alive or if the document's
+ * sequence number is greater than the provided upper bound.
+ */
+ private boolean isPinned(DocumentKey key, long upperBound) {
  if (mutationQueuesContainsKey(key)) {
  return true;
  }

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

@@ -83,17 +83,7 @@ public ImmutableSortedMap<DocumentKey, Document> getAllDocumentsMatchingQuery(Qu
  return result;
  }
 
- /** Remove any documents that the delegate reports as not pinned at the given upper bound. */
- int removeOrphanedDocuments(MemoryLruReferenceDelegate delegate, long upperBound) {
- int count = 0;
- ImmutableSortedMap<DocumentKey, MaybeDocument> updated = docs;
- for (Map.Entry<DocumentKey, MaybeDocument> entry : docs) {
- if (!delegate.isPinned(entry.getKey(), upperBound)) {
- updated = updated.remove(entry.getKey());
- count++;
- }
- }
- docs = updated;
- return count;
+ ImmutableSortedMap<DocumentKey, MaybeDocument> getDocuments() {
+ return docs;
  }
 }