Prefer existing database

Author: simolus3

sqlite3_web/lib/src/client.dart

@@ -535,6 +535,7 @@ final class DatabaseClient implements WebSqlite {
       }
 
       final result = CompatibilityResult.fromJS(response.response as JSObject);
+      existing.addAll(result.existingDatabases);
 
       if (result.canUseIndexedDb) {
         workersReportedIndexedDbSupport = true;

sqlite3_web/lib/src/shared.dart

@@ -6,6 +6,8 @@ import 'dart:async';
 import 'dart:js_interop';
 import 'dart:js_interop_unsafe';
 
+// ignore: implementation_imports
+import 'package:sqlite3/src/wasm/js_interop/new_file_system_access.dart';
 import 'package:web/web.dart';
 
 /// Checks whether IndexedDB is working in the current browser.
@@ -87,6 +89,47 @@ class Lock {
   }
 }
 
+/// Collects all drift OPFS databases.
+Future<List<String>> opfsDatabases() async {
+  final storage = storageManager;
+  if (storage == null) return const [];
+
+  var directory = await storage.directory;
+  try {
+    directory = await directory.getDirectory('drift_db');
+  } on Object {
+    // The drift_db folder doesn't exist, so there aren't any databases.
+    return const [];
+  }
+
+  return [
+    await for (final entry in directory.list())
+      if (entry.isDirectory) entry.name,
+  ];
+}
+
+/// Constructs the path used by drift to store a database in the origin-private
+/// section of the agent's file system.
+String pathForOpfs(String databaseName) {
+  return 'drift_db/$databaseName';
+}
+
+/// Deletes the OPFS folder storing a database with the given [databaseName] if
+/// such folder exists.
+Future<void> deleteDatabaseInOpfs(String databaseName) async {
+  final storage = storageManager;
+  if (storage == null) return;
+
+  var directory = await storage.directory;
+  try {
+    directory = await directory.getDirectory('drift_db');
+    await directory.remove(databaseName, recursive: true);
+  } on Object {
+    // fine, an error probably means that the database didn't exist in the first
+    // place.
+  }
+}
+
 extension CompleteIdbRequest on IDBRequest {
   Future<T> complete<T extends JSAny?>() {
     final completer = Completer<T>.sync();

sqlite3_web/lib/src/worker.dart

@@ -705,6 +705,7 @@ final class WorkerRunner {
 
       var supportsOpfs = false;
       var opfsSupportsReadWriteUnsafe = false;
+      final databaseName = check.databaseName;
       if (check.shouldCheckOpfsCompatibility) {
         (
           basicSupport: supportsOpfs,
@@ -717,14 +718,15 @@ final class WorkerRunner {
           : false;
 
       var sharedCanSpawnDedicated = false;
+      final existingDatabases = <ExistingDatabase>{};
 
       if (check.type == MessageType.sharedCompatibilityCheck) {
         if (globalContext.has('Worker')) {
           sharedCanSpawnDedicated = true;
 
           final worker = useOrSpawnInnerWorker();
           CompatibilityCheck(
-            databaseName: check.databaseName,
+            databaseName: databaseName,
             type: MessageType.dedicatedInSharedCompatibilityCheck,
             requestId: 0,
           ).sendToWorker(worker);
@@ -735,11 +737,23 @@ final class WorkerRunner {
 
           supportsOpfs = result.canUseOpfs;
           opfsSupportsReadWriteUnsafe = result.opfsSupportsReadWriteUnsafe;
+          existingDatabases.addAll(result.existingDatabases);
+        }
+      }
+
+      if (supportsOpfs) {
+        for (final database in await opfsDatabases()) {
+          existingDatabases.add((StorageMode.opfs, database));
+        }
+      }
+      if (supportsIndexedDb && databaseName != null) {
+        if (await checkIndexedDbExists(databaseName)) {
+          existingDatabases.add((StorageMode.indexedDb, databaseName));
         }
       }
 
       return CompatibilityResult(
-        existingDatabases: const [], // todo
+        existingDatabases: existingDatabases.toList(),
         sharedCanSpawnDedicated: sharedCanSpawnDedicated,
         canUseOpfs: supportsOpfs,
         opfsSupportsReadWriteUnsafe: opfsSupportsReadWriteUnsafe,
@@ -878,44 +892,3 @@ Future<(bool, FileSystemSyncAccessHandle)> _tryOpeningWithReadWriteUnsafe(
     return (false, sync);
   }
 }
-
-/// Collects all drift OPFS databases.
-Future<List<String>> opfsDatabases() async {
-  final storage = storageManager;
-  if (storage == null) return const [];
-
-  var directory = await storage.directory;
-  try {
-    directory = await directory.getDirectory('drift_db');
-  } on Object {
-    // The drift_db folder doesn't exist, so there aren't any databases.
-    return const [];
-  }
-
-  return [
-    await for (final entry in directory.list())
-      if (entry.isDirectory) entry.name,
-  ];
-}
-
-/// Constructs the path used by drift to store a database in the origin-private
-/// section of the agent's file system.
-String pathForOpfs(String databaseName) {
-  return 'drift_db/$databaseName';
-}
-
-/// Deletes the OPFS folder storing a database with the given [databaseName] if
-/// such folder exists.
-Future<void> deleteDatabaseInOpfs(String databaseName) async {
-  final storage = storageManager;
-  if (storage == null) return;
-
-  var directory = await storage.directory;
-  try {
-    directory = await directory.getDirectory('drift_db');
-    await directory.remove(databaseName, recursive: true);
-  } on Object {
-    // fine, an error probably means that the database didn't exist in the first
-    // place.
-  }
-}

sqlite3_web/pubspec.yaml

@@ -1,6 +1,6 @@
 name: sqlite3_web
 description: Utilities to simplify accessing sqlite3 on the web, with automated feature detection.
-version: 0.3.2
+version: 0.4.0
 homepage: https://github.com/simolus3/sqlite3.dart/tree/main/sqlite3_web
 repository: https://github.com/simolus3/sqlite3.dart
 
@@ -9,7 +9,7 @@ environment:
 
 dependencies:
   meta: ^1.17.0
-  sqlite3: ^2.7.0
+  sqlite3: ^2.9.4
   stream_channel: ^2.1.2
   web: ^1.0.0
 

sqlite3_web/test/integration_test.dart

@@ -254,5 +254,24 @@ final class _TestConfiguration {
     test('can share databases', () async {
       await driver.testSecond();
     });
+
+    test('re-uses IndexedDB after OPFS becomes available', () async {
+      // In 0.4.0, we've added a new OPFS implementation that would be used by
+      // default on browsers that previously only supported IndexedDB.
+      await driver.openDatabase(
+          implementation: DatabaseImplementation.indexedDbShared);
+      await driver.execute('CREATE TABLE foo (bar TEXT);');
+      await driver.closeDatabase();
+
+      await driver.driver.refresh();
+      await driver.waitReady();
+
+      final features = await driver.probeImplementations();
+      expect(features.existing, [(StorageMode.indexedDb, 'database')]);
+
+      final actualImplementation = await driver.openDatabase();
+      expect(actualImplementation.storage, StorageMode.indexedDb);
+      await driver.execute('INSERT INTO foo DEFAULT VALUES');
+    });
   }
 }