[cloud_firestore] Support for map fields in document pagination (#1781)

Author: creativecreatorormaybenot

packages/cloud_firestore/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.12.6
+
+* Support for `orderBy` on map fields (e.g. `orderBy('cake.flavor')`) for
+  `startAtDocument`, `startAfterDocument`, `endAtDocument`, and `endBeforeDocument` added.
+
 ## 0.12.5+2
 
 * Automatically use version from pubspec.yaml when reporting usage to Firebase.

packages/cloud_firestore/android/src/main/java/io/flutter/plugins/firebase/cloudfirestore/CloudFirestorePlugin.java

@@ -129,7 +129,16 @@ private Object[] getDocumentValues(
     if (orderBy != null) {
       for (List<Object> order : orderBy) {
         String orderByFieldName = (String) order.get(0);
-        data.add(documentData.get(orderByFieldName));
+        if (orderByFieldName.contains(".")) {
+          String[] fieldNameParts = orderByFieldName.split("\\.");
+          Map<String, Object> current = (Map<String, Object>) documentData.get(fieldNameParts[0]);
+          for (int i = 1; i < fieldNameParts.length - 1; i++) {
+            current = (Map<String, Object>) current.get(fieldNameParts[i]);
+          }
+          data.add(current.get(fieldNameParts[fieldNameParts.length - 1]));
+        } else {
+          data.add(documentData.get(orderByFieldName));
+        }
       }
     }
     data.add((boolean) arguments.get("isCollectionGroup") ? document.get("path") : documentId);

packages/cloud_firestore/example/test_driver/cloud_firestore.dart

@@ -210,5 +210,44 @@ void main() {
       await doc1.delete();
       await doc2.delete();
     });
+
+    test('pagination with map', () async {
+      // Populate the database with two test documents.
+      final CollectionReference messages = firestore.collection('messages');
+      final DocumentReference doc1 = messages.document();
+      // Use document ID as a unique identifier to ensure that we don't
+      // collide with other tests running against this database.
+      final String testRun = doc1.documentID;
+      await doc1.setData(<String, dynamic>{
+        'cake': <String, dynamic>{
+          'flavor': <String, dynamic>{'type': 1, 'test_run': testRun}
+        }
+      });
+
+      final DocumentSnapshot snapshot1 = await doc1.get();
+      final DocumentReference doc2 = await messages.add(<String, dynamic>{
+        'cake': <String, dynamic>{
+          'flavor': <String, dynamic>{'type': 2, 'test_run': testRun}
+        }
+      });
+
+      QuerySnapshot snapshot;
+      List<DocumentSnapshot> results;
+
+      // One pagination call is enough as all of the pagination methods use the same method to get data internally.
+      snapshot = await messages
+          .orderBy('cake.flavor.type')
+          .where('cake.flavor.test_run', isEqualTo: testRun)
+          .startAtDocument(snapshot1)
+          .getDocuments();
+      results = snapshot.documents;
+
+      expect(results.length, 2);
+      expect(results[0].data['cake']['flavor']['type'], 1);
+      expect(results[1].data['cake']['flavor']['type'], 2);
+
+      await doc1.delete();
+      await doc2.delete();
+    });
   });
 }

packages/cloud_firestore/ios/Classes/CloudFirestorePlugin.m

@@ -32,7 +32,17 @@
     for (id item in orderBy) {
       NSArray *orderByParameters = item;
       NSString *fieldName = orderByParameters[0];
-      [values addObject:[documentData objectForKey:fieldName]];
+      if ([fieldName rangeOfString:@"."].location != NSNotFound) {
+        NSArray *fieldNameParts = [fieldName componentsSeparatedByString:@"."];
+        NSDictionary *currentMap = [documentData objectForKey:[fieldNameParts objectAtIndex:0]];
+        for (int i = 1; i < [fieldNameParts count] - 1; i++) {
+          currentMap = [currentMap objectForKey:[fieldNameParts objectAtIndex:i]];
+        }
+        [values addObject:[currentMap objectForKey:[fieldNameParts
+                                                       objectAtIndex:[fieldNameParts count] - 1]]];
+      } else {
+        [values addObject:[documentData objectForKey:fieldName]];
+      }
     }
   }
   if (isCollectionGroup) {

packages/cloud_firestore/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for Cloud Firestore, a cloud-hosted, noSQL database
   live synchronization and offline support on Android and iOS.
 author: Flutter Team <flutter-dev@googlegroups.com>
 homepage: https://github.com/flutter/plugins/tree/master/packages/cloud_firestore
-version: 0.12.5+2
+version: 0.12.6
 
 flutter:
   plugin: