Cleanup and Reactivity Support

Author: aashishpatil-g

packages/firebase_data_connect/firebase_data_connect/lib/firebase_data_connect.dart

@@ -40,6 +40,6 @@ export 'src/optional.dart'
         listSerializer;
 export 'src/timestamp.dart' show Timestamp;
 export 'src/cache/cache_data_types.dart' show CacheSettings, QueryFetchPolicy;
-export 'src/cache/cache_manager.dart' show Cache;
-export 'src/cache/cache_provider.dart' show CacheProvider;
-export 'src/cache/sqlite_cache_provider.dart' show SQLite3CacheProvider;
+//export 'src/cache/cache_manager.dart' show Cache;
+//export 'src/cache/cache_provider.dart' show CacheProvider;
+//export 'src/cache/sqlite_cache_provider.dart' show SQLite3CacheProvider;

packages/firebase_data_connect/firebase_data_connect/lib/src/cache/cache_data_types.dart

@@ -115,14 +115,22 @@ class EntityDataObject {
   Map<String, dynamic> _serverValues = {};
 
   /// A set of identifiers for the `QueryRef`s that reference this EDO.
-  final Set<String> referencedFrom = {};
+  Set<String> referencedFrom = {};
 
-  void updateServerValue(String prop, dynamic value) {
+  void updateServerValue(String prop, dynamic value, String? requestor) {
     _serverValues[prop] = value;
+
+    if (requestor != null) {
+      referencedFrom.add(requestor);
+    }
   }
 
-  void setServerValues(Map<String, dynamic> values) {
+  void setServerValues(Map<String, dynamic> values, String? requestor) {
     _serverValues = values;
+
+    if (requestor != null) {
+      referencedFrom.add(requestor);
+    }
   }
 
   /// Dictionary of prop-values contained in this EDO
@@ -137,16 +145,26 @@ class EntityDataObject {
 
   String toRawJson() => json.encode(toJson());
 
-  factory EntityDataObject.fromJson(Map<String, dynamic> json) =>
-      EntityDataObject(
-        guid: json[GlobalIDKey] as String,
-      ).._serverValues =
-          Map<String, dynamic>.from(json['_serverValues'] as Map);
-
   Map<String, dynamic> toJson() => {
         GlobalIDKey: guid,
         '_serverValues': _serverValues,
+        'referencedFrom': referencedFrom.toList(),
       };
+
+  factory EntityDataObject.fromJson(Map<String, dynamic> json) {
+    EntityDataObject edo = EntityDataObject(
+      guid: json[GlobalIDKey] as String,
+    );
+    edo.setServerValues(
+        Map<String, dynamic>.from(json['_serverValues'] as Map), null);
+
+    List<dynamic>? rf = json['referencedFrom'];
+    if (rf != null) {
+      edo.referencedFrom = rf.cast<String>().toSet();
+    }
+
+    return edo;
+  }
 }
 
 /// A tree-like data structure that represents the dehydrated or hydrated query result.
@@ -174,12 +192,12 @@ class EntityNode {
 
   factory EntityNode.fromJson(
       Map<String, dynamic> json, CacheProvider cacheProvider) {
-    EntityDataObject? entity = null;
+    EntityDataObject? entity;
     if (json[GlobalIDKey] != null) {
       entity = cacheProvider.getEntityDataObject(json[GlobalIDKey]);
     }
 
-    Map<String, dynamic>? scalars = null;
+    Map<String, dynamic>? scalars;
     if (json[scalarsKey] != null) {
       scalars = json[scalarsKey];
     }

packages/firebase_data_connect/firebase_data_connect/lib/src/cache/cache_manager.dart

@@ -13,14 +13,12 @@
 // limitations under the License.
 
 import 'dart:async';
-import 'dart:convert';
 import 'dart:developer' as developer;
 
 import 'package:firebase_auth/firebase_auth.dart';
 import 'package:firebase_data_connect/firebase_data_connect.dart';
-import 'package:firebase_data_connect/src/cache/in_memory_cache_provider.dart';
-import 'package:firebase_data_connect/src/cache/sqlite_cache_provider.dart';
-import 'package:flutter/foundation.dart';
+import 'cache_provider.dart';
+import 'in_memory_cache_provider.dart' if (dart.library.io) 'sqlite_cache_provider.dart';
 
 import '../common/common_library.dart';
 
@@ -38,10 +36,10 @@ class Cache {
 
   factory Cache(CacheSettings settings, FirebaseDataConnect dataConnect) {
     Cache c = Cache._internal(settings, dataConnect);
-     
+
     c._initializeProvider();
     c._listenForAuthChanges();
-    
+
     return c;
   }
 
@@ -60,31 +58,20 @@ class Cache {
       return;
     }
 
-    if (kIsWeb) {
-      // change this once we support persistence for web
-      _cacheProvider = InMemoryCacheProvider(identifier);
-      providerInitialization = _cacheProvider?.initialize();
-      return;
-    }
+    bool memory = _settings.storage == CacheStorage.memory;
+    _cacheProvider = cacheImplementation(identifier, memory);
 
-    switch (_settings.storage) {
-      case CacheStorage.memory:
-        _cacheProvider = SQLite3CacheProvider(identifier, memory: true);
-      case CacheStorage.persistent:
-        _cacheProvider = SQLite3CacheProvider(identifier);
-    }
     providerInitialization = _cacheProvider?.initialize();
   }
 
   void _listenForAuthChanges() {
     if (dataConnect.auth == null) {
-      developer.log('Not listening for auth changes since no auth instance in data connect');
+      developer.log(
+          'Not listening for auth changes since no auth instance in data connect');
       return;
     }
 
-    dataConnect.auth!
-        .authStateChanges()
-        .listen((User? user) {
+    dataConnect.auth!.authStateChanges().listen((User? user) {
       _initializeProvider();
     });
   }
@@ -107,23 +94,25 @@ class Cache {
         queryId, serverResponse.data, _cacheProvider!);
 
     EntityNode rootNode = dehydrationResult.dehydratedTree;
-    String dehydratedJson =
-        jsonEncode(rootNode.toJson(mode: EncodingMode.dehydrated));
+    Map<String, dynamic> dehydratedMap =
+        rootNode.toJson(mode: EncodingMode.dehydrated);
 
     Duration ttl = serverResponse.ttl != null
         ? serverResponse.ttl!
         : Duration(seconds: 10);
     final resultTree = ResultTree(
-        data: rootNode.toJson(
-            mode: EncodingMode
-                .dehydrated), // Storing the original response for now
+        data: dehydratedMap,
         ttl: ttl, // Default TTL
         cachedAt: DateTime.now(),
         lastAccessed: DateTime.now());
 
     _cacheProvider!.saveResultTree(queryId, resultTree);
 
-    _impactedQueryController.add(dehydrationResult.impactedQueryIds);
+    Set<String> impactedQueryIds = dehydrationResult.impactedQueryIds;
+    impactedQueryIds.remove(queryId); // remove query being cached
+    print(
+        'adding to impactedQueryController ${dehydrationResult.impactedQueryIds}');
+    _impactedQueryController.add(impactedQueryIds);
   }
 
   /// Fetches a cached result.

packages/firebase_data_connect/firebase_data_connect/lib/src/cache/in_memory_cache_provider.dart

@@ -32,6 +32,7 @@ class InMemoryCacheProvider implements CacheProvider {
   @override
   Future<bool> initialize() async {
     // nothing to be intialized
+    print('Initialize inmemory provider called');
     return true;
   }
 
@@ -54,6 +55,7 @@ class InMemoryCacheProvider implements CacheProvider {
   EntityDataObject getEntityDataObject(String guid) {
     EntityDataObject? edo = _edos[guid];
     if (edo != null) {
+      print('Returning existing edo for $guid');
       return edo;
     } else {
       edo = EntityDataObject(guid: guid);
@@ -73,3 +75,5 @@ class InMemoryCacheProvider implements CacheProvider {
     _edos.clear();
   }
 }
+
+CacheProvider cacheImplementation(String identifier, bool memory) => InMemoryCacheProvider(identifier);

packages/firebase_data_connect/firebase_data_connect/lib/src/cache/result_tree_processor.dart

@@ -16,8 +16,6 @@ import '../common/common_library.dart';
 import 'cache_data_types.dart';
 import 'cache_provider.dart';
 
-import 'dart:convert';
-
 class DehydrationResult {
   final EntityNode dehydratedTree;
   final Set<String> impactedQueryIds;
@@ -47,6 +45,7 @@ class ResultTreeProcessor {
       CacheProvider cacheProvider, Set<String> impactedQueryIds) {
     if (data is Map<String, dynamic>) {
       if (data.containsKey(GlobalIDKey)) {
+        // data contains a unique entity id. we can normalize
         final guid = data[GlobalIDKey] as String;
 
         final serverValues = <String, dynamic>{};
@@ -76,7 +75,7 @@ class ResultTreeProcessor {
         final existingEdo = cacheProvider.getEntityDataObject(guid);
         existingEdo.referencedFrom.add(queryId);
         impactedQueryIds.addAll(existingEdo.referencedFrom);
-        existingEdo.setServerValues(serverValues);
+        existingEdo.setServerValues(serverValues, queryId);
         cacheProvider.saveEntityDataObject(existingEdo);
 
         return EntityNode(
@@ -85,6 +84,7 @@ class ResultTreeProcessor {
             nestedObjectLists: nestedObjectLists);
       } else {
         // GlobalID check
+        // no entity id. scalar data must be stored inline.
         final scalarValues = <String, dynamic>{};
         final nestedObjects = <String, EntityNode>{};
         final nestedObjectLists = <String, List<EntityNode>>{};
@@ -107,7 +107,7 @@ class ResultTreeProcessor {
             scalarValues[key] = value;
           }
         }
-      
+
         return EntityNode(
             scalarValues: scalarValues,
             nestedObjects: nestedObjects,

packages/firebase_data_connect/firebase_data_connect/lib/src/cache/sqlite_cache_provider.dart

@@ -24,20 +24,24 @@ class SQLite3CacheProvider implements CacheProvider {
   final String _identifier;
   final bool memory;
 
+  final String entityDataTable = 'entity_data';
+  final String resultTreeTable = 'query_results';
+  final String entityDataRefsTable = 'entity_data_query_refs';
+
   SQLite3CacheProvider(this._identifier, {this.memory = false});
 
   @override
   Future<bool> initialize() async {
     try {
-    if (memory) {
-      _db = sqlite3.open(':memory:');
-    } else {
-      final dbPath = await getApplicationDocumentsDirectory();
-      final path = join(dbPath.path, '{$_identifier}.db');
-      _db = sqlite3.open(path);
-    }
-    _createTables();
-    return true;
+      if (memory) {
+        _db = sqlite3.open(':memory:');
+      } else {
+        final dbPath = await getApplicationDocumentsDirectory();
+        final path = join(dbPath.path, '{$_identifier}.db');
+        _db = sqlite3.open(path);
+      }
+      _createTables();
+      return true;
     } catch (e) {
       developer.log('Error initializing SQLiteProvider $e');
       return false;
@@ -46,13 +50,13 @@ class SQLite3CacheProvider implements CacheProvider {
 
   void _createTables() {
     _db.execute('''
-      CREATE TABLE IF NOT EXISTS result_trees (
+      CREATE TABLE IF NOT EXISTS $resultTreeTable (
         query_id TEXT PRIMARY KEY,
         result_tree TEXT
       );
     ''');
     _db.execute('''
-      CREATE TABLE IF NOT EXISTS entity_data_objects (
+      CREATE TABLE IF NOT EXISTS $entityDataTable (
         guid TEXT PRIMARY KEY,
         entity_data_object TEXT
       );
@@ -66,14 +70,14 @@ class SQLite3CacheProvider implements CacheProvider {
 
   @override
   void clear() {
-    _db.execute('DELETE FROM result_trees');
-    _db.execute('DELETE FROM entity_data_objects');
+    _db.execute('DELETE FROM $resultTreeTable');
+    _db.execute('DELETE FROM $entityDataTable');
   }
 
   @override
   EntityDataObject getEntityDataObject(String guid) {
     final resultSet = _db.select(
-      'SELECT entity_data_object FROM entity_data_objects WHERE guid = ?',
+      'SELECT entity_data_object FROM $entityDataTable WHERE guid = ?',
       [guid],
     );
     if (resultSet.isEmpty) {
@@ -88,7 +92,7 @@ class SQLite3CacheProvider implements CacheProvider {
   @override
   ResultTree? getResultTree(String queryId) {
     final resultSet = _db.select(
-      'SELECT result_tree FROM result_trees WHERE query_id = ?',
+      'SELECT result_tree FROM $resultTreeTable WHERE query_id = ?',
       [queryId],
     );
     if (resultSet.isEmpty) {
@@ -104,17 +108,22 @@ class SQLite3CacheProvider implements CacheProvider {
 
   @override
   void saveEntityDataObject(EntityDataObject edo) {
+    String rawJson = edo.toRawJson();
+    developer.log(
+        'saveEntityDataObject ${edo.guid} refs ${edo.referencedFrom} $rawJson');
     _db.execute(
-      'INSERT OR REPLACE INTO entity_data_objects (guid, entity_data_object) VALUES (?, ?)',
-      [edo.guid, edo.toRawJson()],
+      'INSERT OR REPLACE INTO $entityDataTable (guid, entity_data_object) VALUES (?, ?)',
+      [edo.guid, rawJson],
     );
   }
 
   @override
   void saveResultTree(String queryId, ResultTree resultTree) {
     _db.execute(
-      'INSERT OR REPLACE INTO result_trees (query_id, result_tree) VALUES (?, ?)',
+      'INSERT OR REPLACE INTO $resultTreeTable (query_id, result_tree) VALUES (?, ?)',
       [queryId, resultTree.toRawJson()],
     );
   }
 }
+
+CacheProvider cacheImplementation(String identifier, bool memory) => SQLite3CacheProvider(identifier, memory: memory);