Add createTime to Document.

packages/firestore/src/local/local_documents_view.ts

@@ -46,7 +46,6 @@ import { FieldMask } from '../model/field_mask';
 import {
   calculateOverlayMutation,
   mutationApplyToLocalView,
-  MutationType,
   PatchMutation
 } from '../model/mutation';
 import { Overlay } from '../model/overlay';
@@ -92,7 +91,7 @@ export class LocalDocumentsView {
       .getOverlay(transaction, key)
       .next(value => {
         overlay = value;
-        return this.getBaseDocument(transaction, key, overlay);
+        return this.remoteDocumentCache.getEntry(transaction, key);
       })
       .next(document => {
         if (overlay !== null) {
@@ -424,11 +423,11 @@ export class LocalDocumentsView {
               if (originalDocs.get(key)) {
                 return PersistencePromise.resolve();
               }
-              return this.getBaseDocument(transaction, key, overlay).next(
-                doc => {
+              return this.remoteDocumentCache
+                .getEntry(transaction, key)
+                .next(doc => {
                   modifiedDocs = modifiedDocs.insert(key, doc);
-                }
-              );
+                });
             }
           )
             .next(() =>
@@ -550,15 +549,4 @@ export class LocalDocumentsView {
         return results;
       });
   }
-
-  /** Returns a base document that can be used to apply `overlay`. */
-  private getBaseDocument(
-    transaction: PersistenceTransaction,
-    key: DocumentKey,
-    overlay: Overlay | null
-  ): PersistencePromise<MutableDocument> {
-    return overlay === null || overlay.mutation.type === MutationType.Patch
-      ? this.remoteDocumentCache.getEntry(transaction, key)
-      : PersistencePromise.resolve(MutableDocument.newInvalidDocument(key));
-  }
 }

packages/firestore/src/model/document.ts

@@ -101,6 +101,13 @@ export interface Document {
    */
   readonly readTime: SnapshotVersion;
 
+  /**
+   * The timestamp at which the document was created. This value increases
+   * monotonically when a document is deleted then recreated. It can also be
+   * compared to `createTime` of other documents and the `readTime` of a query.
+   */
+  readonly createTime: SnapshotVersion;
+
   /** The underlying data of this document or an empty value if no data exists. */
   readonly data: ObjectValue;
 
@@ -163,6 +170,7 @@ export class MutableDocument implements Document {
     private documentType: DocumentType,
     public version: SnapshotVersion,
     public readTime: SnapshotVersion,
+    public createTime: SnapshotVersion,
     public data: ObjectValue,
     private documentState: DocumentState
   ) {}
@@ -175,8 +183,9 @@ export class MutableDocument implements Document {
     return new MutableDocument(
       documentKey,
       DocumentType.INVALID,
-      SnapshotVersion.min(),
-      SnapshotVersion.min(),
+      /* version */ SnapshotVersion.min(),
+      /* readTime */ SnapshotVersion.min(),
+      /* createTime */ SnapshotVersion.min(),
       ObjectValue.empty(),
       DocumentState.SYNCED
     );
@@ -189,13 +198,15 @@ export class MutableDocument implements Document {
   static newFoundDocument(
     documentKey: DocumentKey,
     version: SnapshotVersion,
+    createTime: SnapshotVersion,
     value: ObjectValue
   ): MutableDocument {
     return new MutableDocument(
       documentKey,
       DocumentType.FOUND_DOCUMENT,
-      version,
-      SnapshotVersion.min(),
+      /* version */ version,
+      /* readTime */ SnapshotVersion.min(),
+      /* createTime */ createTime,
       value,
       DocumentState.SYNCED
     );
@@ -209,8 +220,9 @@ export class MutableDocument implements Document {
     return new MutableDocument(
       documentKey,
       DocumentType.NO_DOCUMENT,
-      version,
-      SnapshotVersion.min(),
+      /* version */ version,
+      /* readTime */ SnapshotVersion.min(),
+      /* createTime */ SnapshotVersion.min(),
       ObjectValue.empty(),
       DocumentState.SYNCED
     );
@@ -228,8 +240,9 @@ export class MutableDocument implements Document {
     return new MutableDocument(
       documentKey,
       DocumentType.UNKNOWN_DOCUMENT,
-      version,
-      SnapshotVersion.min(),
+      /* version */ version,
+      /* readTime */ SnapshotVersion.min(),
+      /* createTime */ SnapshotVersion.min(),
       ObjectValue.empty(),
       DocumentState.HAS_COMMITTED_MUTATIONS
     );
@@ -243,6 +256,18 @@ export class MutableDocument implements Document {
     version: SnapshotVersion,
     value: ObjectValue
   ): MutableDocument {
+    // If a document is switching state from being an invalid or deleted
+    // document to a valid (FOUND_DOCUMENT) document, either due to receiving an
+    // update from Watch or due to applying a local set mutation on top
+    // of a deleted document, our best guess about its createTime would be the
+    // version at which the document transitioned to a FOUND_DOCUMENT.
+    if (
+      this.createTime.isEqual(SnapshotVersion.min()) &&
+      (this.documentType === DocumentType.NO_DOCUMENT ||
+        this.documentType === DocumentType.INVALID)
+    ) {
+      this.createTime = version;
+    }
     this.version = version;
     this.documentType = DocumentType.FOUND_DOCUMENT;
     this.data = value;
@@ -340,6 +365,7 @@ export class MutableDocument implements Document {
       this.documentType,
       this.version,
       this.readTime,
+      this.createTime,
       this.data.clone(),
       this.documentState
     );
@@ -350,6 +376,7 @@ export class MutableDocument implements Document {
       `Document(${this.key}, ${this.version}, ${JSON.stringify(
         this.data.value
       )}, ` +
+      `{createTime: ${this.createTime}}), ` +
       `{documentType: ${this.documentType}}), ` +
       `{documentState: ${this.documentState}})`
     );

packages/firestore/src/remote/serializer.ts

@@ -404,7 +404,8 @@ export function toDocument(
   return {
     name: toName(serializer, document.key),
     fields: document.data.value.mapValue.fields,
-    updateTime: toTimestamp(serializer, document.version.toTimestamp())
+    updateTime: toTimestamp(serializer, document.version.toTimestamp()),
+    createTime: toTimestamp(serializer, document.createTime.toTimestamp())
   };
 }
 
@@ -415,8 +416,19 @@ export function fromDocument(
 ): MutableDocument {
   const key = fromName(serializer, document.name!);
   const version = fromVersion(document.updateTime!);
+  // If we read a document from persistence that is missing createTime, it's due
+  // to older SDK versions not storing this information. In such cases, we'll
+  // set the createTime to zero. This can be removed in the long term.
+  const createTime = document.createTime
+    ? fromVersion(document.createTime)
+    : SnapshotVersion.min();
   const data = new ObjectValue({ mapValue: { fields: document.fields } });
-  const result = MutableDocument.newFoundDocument(key, version, data);
+  const result = MutableDocument.newFoundDocument(
+    key,
+    version,
+    createTime,
+    data
+  );
   if (hasCommittedMutations) {
     result.setHasCommittedMutations();
   }
@@ -435,8 +447,11 @@ function fromFound(
   assertPresent(doc.found.updateTime, 'doc.found.updateTime');
   const key = fromName(serializer, doc.found.name);
   const version = fromVersion(doc.found.updateTime);
+  const createTime = doc.found.createTime
+    ? fromVersion(doc.found.createTime)
+    : SnapshotVersion.min();
   const data = new ObjectValue({ mapValue: { fields: doc.found.fields } });
-  return MutableDocument.newFoundDocument(key, version, data);
+  return MutableDocument.newFoundDocument(key, version, createTime, data);
 }
 
 function fromMissing(
@@ -502,10 +517,18 @@ export function fromWatchChange(
     );
     const key = fromName(serializer, entityChange.document.name);
     const version = fromVersion(entityChange.document.updateTime);
+    const createTime = entityChange.document.createTime
+      ? fromVersion(entityChange.document.createTime)
+      : SnapshotVersion.min();
     const data = new ObjectValue({
       mapValue: { fields: entityChange.document.fields }
     });
-    const doc = MutableDocument.newFoundDocument(key, version, data);
+    const doc = MutableDocument.newFoundDocument(
+      key,
+      version,
+      createTime,
+      data
+    );
     const updatedTargetIds = entityChange.targetIds || [];
     const removedTargetIds = entityChange.removedTargetIds || [];
     watchChange = new DocumentWatchChange(