Merge branch 'mrschmidt/indexfree-2' into mrschmidt/indexfree-3

Author: schmidt-sebastian

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

@@ -17,14 +17,14 @@
 import static com.google.firebase.firestore.util.Assert.fail;
 import static com.google.firebase.firestore.util.Assert.hardAssert;
 
+import com.google.firebase.Timestamp;
 import com.google.firebase.database.collection.ImmutableSortedMap;
 import com.google.firebase.firestore.core.Query;
 import com.google.firebase.firestore.model.Document;
 import com.google.firebase.firestore.model.DocumentCollections;
 import com.google.firebase.firestore.model.DocumentKey;
 import com.google.firebase.firestore.model.MaybeDocument;
 import com.google.firebase.firestore.model.ResourcePath;
-import com.google.firebase.firestore.model.SnapshotVersion;
 import com.google.firebase.firestore.util.BackgroundQueue;
 import com.google.firebase.firestore.util.Executors;
 import com.google.protobuf.InvalidProtocolBufferException;
@@ -52,16 +52,18 @@ final class SQLiteRemoteDocumentCache implements RemoteDocumentCache {
   @Override
   public void add(MaybeDocument maybeDocument) {
     String path = pathForKey(maybeDocument.getKey());
-    SnapshotVersion snapshotVersion = maybeDocument.getVersion();
+    Timestamp timestamp = maybeDocument.getVersion().getTimestamp();
     MessageLite message = serializer.encodeMaybeDocument(maybeDocument);
 
     statsCollector.recordRowsWritten(STATS_TAG, 1);
 
     db.execute(
-        "INSERT OR REPLACE INTO remote_documents (path, snapshot_version_micros, contents) "
-            + "VALUES (?, ?, ?)",
+        "INSERT OR REPLACE INTO remote_documents "
+            + "(path, update_time_seconds, update_time_nanos, contents) "
+            + "VALUES (?, ?, ?, ?)",
         path,
-        snapshotVersion.toMicroseconds(),
+        timestamp.getSeconds(),
+        timestamp.getNanoseconds(),
         message.toByteArray());
 
     db.getIndexManager().addToCollectionParentIndex(maybeDocument.getKey().getPath().popLast());

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

@@ -45,8 +45,16 @@ class SQLiteSchema {
   /**
    * The version of the schema. Increase this by one for each migration added to runMigrations
    * below.
+   *
+   * <p>TODO(index-free): The migration to schema version 9 doesn't backfill `update_time` as this
+   * requires rewriting the RemoteDocumentCache. For index-free queries to efficiently handle
+   * existing documents, we still need to populate update_time for all existing entries, drop the
+   * RemoteDocumentCache or ask users to invoke `clearPersistence()` manually. If we decide to
+   * backfill or drop the contents of the RemoteDocumentCache, we need to perform an additional
+   * schema migration.
    */
   static final int VERSION = 9;
+
   // Remove this constant and increment VERSION to enable indexing support
   static final int INDEXING_SUPPORT_VERSION = VERSION + 1;
 
@@ -356,8 +364,12 @@ private void addSequenceNumber() {
   }
 
   private void addUpdateTime() {
-    if (!tableContainsColumn("remote_documents", "snapshot_version_micros")) {
-      db.execSQL("ALTER TABLE remote_documents ADD COLUMN snapshot_version_micros INTEGER");
+    if (!tableContainsColumn("remote_documents", "update_time_seconds")) {
+      hardAssert(
+          !tableContainsColumn("remote_documents", "update_time_nanos"),
+          "Table contained update_time_seconds, but is missing update_time_nanos");
+      db.execSQL("ALTER TABLE remote_documents ADD COLUMN update_time_seconds INTEGER");
+      db.execSQL("ALTER TABLE remote_documents ADD COLUMN update_time_nanos INTEGER");
     }
   }
 

firebase-firestore/src/main/java/com/google/firebase/firestore/model/SnapshotVersion.java

@@ -15,7 +15,6 @@
 package com.google.firebase.firestore.model;
 
 import com.google.firebase.Timestamp;
-import java.util.concurrent.TimeUnit;
 
 /**
  * A version of a document in Firestore. This corresponds to the version timestamp, such as
@@ -37,12 +36,6 @@ public Timestamp getTimestamp() {
     return timestamp;
   }
 
-  /** Returns the microseconds since EPOCH that this snapshot version represents. */
-  public long toMicroseconds() {
-    return TimeUnit.MICROSECONDS.convert(timestamp.getSeconds(), TimeUnit.SECONDS)
-        + TimeUnit.MICROSECONDS.convert(timestamp.getNanoseconds(), TimeUnit.NANOSECONDS);
-  }
-
   @Override
   public int compareTo(SnapshotVersion other) {
     return timestamp.compareTo(other.timestamp);