Change removeMutationBatch to remove a single batch (#30)

Author: schmidt-sebastian

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

@@ -176,7 +176,9 @@ private void startMutationQueue() {
             if (!batches.isEmpty()) {
               // NOTE: This could be more efficient if we had a removeBatchesThroughBatchID, but
               // this set should be very small and this code should go away eventually.
-              mutationQueue.removeMutationBatches(batches);
+              for (MutationBatch batch : batches) {
+                mutationQueue.removeMutationBatch(batch);
+              }
             }
           }
         });
@@ -641,9 +643,9 @@ private Set<DocumentKey> removeMutationBatches(List<MutationBatch> batches) {
       for (Mutation mutation : batch.getMutations()) {
         affectedDocs.add(mutation.getKey());
       }
+      mutationQueue.removeMutationBatch(batch);
     }
 
-    mutationQueue.removeMutationBatches(batches);
     return affectedDocs;
   }
 

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

@@ -328,69 +328,40 @@ private List<MutationBatch> lookupMutationBatches(ImmutableSortedSet<Integer> ba
   }
 
   @Override
-  public void removeMutationBatches(List<MutationBatch> batches) {
-    int batchCount = batches.size();
-    hardAssert(batchCount > 0, "Should not remove mutations when none exist.");
-
-    int firstBatchId = batches.get(0).getBatchId();
-
-    int queueCount = queue.size();
-
+  public void removeMutationBatch(MutationBatch batch) {
     // Find the position of the first batch for removal. This need not be the first entry in the
     // queue.
-    int startIndex = indexOfExistingBatchId(firstBatchId, "removed");
+    int batchIndex = indexOfExistingBatchId(batch.getBatchId(), "removed");
     hardAssert(
-        queue.get(startIndex).getBatchId() == firstBatchId,
+        queue.get(batchIndex).getBatchId() == batch.getBatchId(),
         "Removed batches must exist in the queue");
 
-    // Check that removed batches are contiguous (while excluding tombstones).
-    int batchIndex = 1;
-    int queueIndex = startIndex + 1;
-    while (batchIndex < batchCount && queueIndex < queueCount) {
-      MutationBatch batch = queue.get(queueIndex);
-      if (batch.isTombstone()) {
-        queueIndex++;
-        continue;
-      }
-
-      hardAssert(
-          batch.getBatchId() == batches.get(batchIndex).getBatchId(),
-          "Removed batches must be contiguous in the queue");
-      batchIndex++;
-      queueIndex++;
-    }
-
     // Only actually remove batches if removing at the front of the queue. Previously rejected
     // batches may have left tombstones in the queue, so expand the removal range to include any
     // tombstones.
-    if (startIndex == 0) {
-      for (; queueIndex < queueCount; queueIndex++) {
-        MutationBatch batch = queue.get(queueIndex);
-        if (!batch.isTombstone()) {
+    if (batchIndex == 0) {
+      int endIndex = 1;
+      for (; endIndex < queue.size(); endIndex++) {
+        MutationBatch currentBatch = queue.get(endIndex);
+        if (!currentBatch.isTombstone()) {
           break;
         }
       }
 
-      queue.subList(startIndex, queueIndex).clear();
+      queue.subList(batchIndex, endIndex).clear();
 
     } else {
-      // Mark tombstones
-      for (int i = startIndex; i < queueIndex; i++) {
-        queue.set(i, queue.get(i).toTombstone());
-      }
+      queue.set(batchIndex, queue.get(batchIndex).toTombstone());
     }
 
     // Remove entries from the index too.
     ImmutableSortedSet<DocumentReference> references = batchesByDocumentKey;
-    for (MutationBatch batch : batches) {
-      int batchId = batch.getBatchId();
-      for (Mutation mutation : batch.getMutations()) {
-        DocumentKey key = mutation.getKey();
-        persistence.getReferenceDelegate().removeMutationReference(key);
-
-        DocumentReference reference = new DocumentReference(key, batchId);
-        references = references.remove(reference);
-      }
+    for (Mutation mutation : batch.getMutations()) {
+      DocumentKey key = mutation.getKey();
+      persistence.getReferenceDelegate().removeMutationReference(key);
+
+      DocumentReference reference = new DocumentReference(key, batch.getBatchId());
+      references = references.remove(reference);
     }
     batchesByDocumentKey = references;
   }

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

@@ -137,18 +137,14 @@ List<MutationBatch> getAllMutationBatchesAffectingDocumentKeys(
   List<MutationBatch> getAllMutationBatchesAffectingQuery(Query query);
 
   /**
-   * Removes the given mutation batches from the queue. This is useful in two circumstances:
+   * Removes the given mutation batch from the queue. This is useful in two circumstances:
    *
    * <ul>
    *   <li>Removing applied mutations from the head of the queue
    *   <li>Removing rejected mutations from anywhere in the queue
    * </ul>
-   *
-   * <p>In both cases, the array of mutations to remove must be a contiguous range of batchIds. This
-   * is most easily accomplished by loading mutations with {@link
-   * #getAllMutationBatchesThroughBatchId}.
    */
-  void removeMutationBatches(List<MutationBatch> batches);
+  void removeMutationBatch(MutationBatch batch);
 
   /** Performs a consistency check, examining the mutation queue for any leaks, if possible. */
   void performConsistencyCheck();

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

@@ -421,23 +421,21 @@ public List<MutationBatch> getAllMutationBatchesAffectingQuery(Query query) {
   }
 
   @Override
-  public void removeMutationBatches(List<MutationBatch> batches) {
+  public void removeMutationBatch(MutationBatch batch) {
     SQLiteStatement mutationDeleter =
         db.prepare("DELETE FROM mutations WHERE uid = ? AND batch_id = ?");
 
     SQLiteStatement indexDeleter =
         db.prepare("DELETE FROM document_mutations WHERE uid = ? AND path = ? AND batch_id = ?");
 
-    for (MutationBatch batch : batches) {
-      int batchId = batch.getBatchId();
-      int deleted = db.execute(mutationDeleter, uid, batchId);
-      hardAssert(deleted != 0, "Mutation batch (%s, %d) did not exist", uid, batch.getBatchId());
+    int batchId = batch.getBatchId();
+    int deleted = db.execute(mutationDeleter, uid, batchId);
+    hardAssert(deleted != 0, "Mutation batch (%s, %d) did not exist", uid, batch.getBatchId());
 
-      for (Mutation mutation : batch.getMutations()) {
-        DocumentKey key = mutation.getKey();
-        String path = EncodedPath.encode(key.getPath());
-        db.execute(indexDeleter, uid, path, batchId);
-      }
+    for (Mutation mutation : batch.getMutations()) {
+      DocumentKey key = mutation.getKey();
+      String path = EncodedPath.encode(key.getPath());
+      db.execute(indexDeleter, uid, path, batchId);
     }
   }
 

firebase-firestore/src/test/java/com/google/firebase/firestore/local/MutationQueueTestCase.java

@@ -143,7 +143,7 @@ public void testAcknowledgeThenRemove() {
         name.getMethodName(),
         () -> {
           mutationQueue.acknowledgeBatch(batch1, WriteStream.EMPTY_STREAM_TOKEN);
-          mutationQueue.removeMutationBatches(asList(batch1));
+          mutationQueue.removeMutationBatch(batch1);
         });
 
     assertEquals(0, batchCount());
@@ -536,7 +536,12 @@ private void acknowledgeBatch(MutationBatch batch) {
   /** Calls removeMutationBatches on the mutation queue in a new transaction and commits. */
   private void removeMutationBatches(MutationBatch... batches) {
     persistence.runTransaction(
-        "Remove mutation batches", () -> mutationQueue.removeMutationBatches(asList(batches)));
+        "Remove mutation batches",
+        () -> {
+          for (MutationBatch batch : batches) {
+            mutationQueue.removeMutationBatch(batch);
+          }
+        });
   }
 
   /** Returns the number of mutation batches in the mutation queue. */