Support custom directory in drift_flutter

Closes #3372
Closes #3374

docs/lib/snippets/setup/database.dart

@@ -12,6 +12,7 @@ import 'package:drift/native.dart';
 // #enddocregion sqlite3
 // #docregion postgres
 import 'package:drift_postgres/drift_postgres.dart';
+import 'package:path_provider/path_provider.dart';
 import 'package:postgres/postgres.dart' as pg;
 // #enddocregion postgres
 
@@ -51,9 +52,14 @@ class AppDatabase extends _$AppDatabase {
 class OpenFlutter {
 // #docregion flutter
   static QueryExecutor _openConnection() {
-    // `driftDatabase` from `package:drift_flutter` stores the database in
-    // `getApplicationDocumentsDirectory()`.
-    return driftDatabase(name: 'my_database');
+    return driftDatabase(
+      name: 'my_database',
+      native: DriftNativeOptions(
+        // By default, `driftDatabase` from `package:drift_flutter` stores the
+        // database files in `getApplicationDocumentsDirectory()`.
+        databaseDirectory: getApplicationSupportDirectory,
+      ),
+    );
   }
 }
 // #enddocregion flutter

drift_flutter/CHANGELOG.md

@@ -1,6 +1,8 @@
 ## 0.2.4-dev
 
 - Allow providing a custom temporary directory.
+- Allow providing a custom database directory, making it easier to swap out the
+  default `getApplicationDocumentsDirectory()`.
 
 ## 0.2.3
 

drift_flutter/lib/src/connect.dart

@@ -65,8 +65,26 @@ final class DriftNativeOptions {
   ///
   /// This function, which can be asynchronous for convenience, allows using
   /// a custom database path in another directory.
+  ///
+  /// At most one of [databasePath] or [databaseDirectory] may be used. Using
+  /// [databasePath] allows more control over the file name, while
+  /// [databaseDirectory] can be used to select another directory from
+  /// `path_provider` more easily.
   final Future<String> Function()? databasePath;
 
+  /// An optional function returning either a string or a `Directory` that will
+  /// be used as a directory to store the database.
+  ///
+  /// By default, drift will use `getApplicationDocumentsDirectory()` function
+  /// from `package:path_provider` as a directory an `$name.sqlite` as a file
+  /// name in that directory.
+  ///
+  /// At most one of [databasePath] or [databaseDirectory] may be used. Using
+  /// [databasePath] allows more control over the file name, while
+  /// [databaseDirectory] can be used to select another directory from
+  /// `path_provider` more easily.
+  final Future<Object> Function()? databaseDirectory;
+
   /// An optional callback returning a temporary directory.
   ///
   /// For larger queries, sqlite3 might store intermediate results in memory.
@@ -88,6 +106,10 @@ final class DriftNativeOptions {
   const DriftNativeOptions({
     this.shareAcrossIsolates = false,
     this.databasePath,
+    this.databaseDirectory,
     this.tempDirectoryPath,
-  });
+  }) : assert(
+          databasePath == null || databaseDirectory == null,
+          'databasePath and databaseDirectory must not both be set.',
+        );
 }

drift_flutter/lib/src/native.dart

@@ -34,8 +34,22 @@ QueryExecutor driftDatabase({
     if (native?.databasePath case final lookupPath?) {
       return File(await lookupPath());
     } else {
-      final dbFolder = await getApplicationDocumentsDirectory();
-      return File(p.join(dbFolder.path, '$name.sqlite'));
+      final resolvedDirectory = await (native?.databaseDirectory ??
+          getApplicationDocumentsDirectory)();
+
+      return File(p.join(
+        switch (resolvedDirectory) {
+          Directory(:final path) => path,
+          final String path => path,
+          final other => throw ArgumentError.value(
+              other,
+              'other',
+              'databaseDirectory on DriftNativeOptions must resolve to a '
+                  'directory or a path as string.',
+            )
+        },
+        '$name.sqlite',
+      ));
     }
   }
 

drift_flutter/pubspec.yaml

@@ -1,6 +1,6 @@
 name: drift_flutter
 description: Easily set up drift databases across platforms in Flutter apps.
-version: 0.2.3
+version: 0.2.4-dev
 repository: https://github.com/simolus3/drift
 homepage: https://drift.simonbinder.eu/
 issue_tracker: https://github.com/simolus3/drift/issues

drift_flutter/test/native_test.dart

@@ -14,6 +14,7 @@ import 'package:drift_flutter/src/native.dart'
     show PingWithTimeout, hasConfiguredSqlite, portName;
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:path_provider/path_provider.dart';
 import 'package:sqlite3/sqlite3.dart';
 import 'package:test_descriptor/test_descriptor.dart' as d;
 
@@ -28,6 +29,7 @@ void main() {
     return switch (call.method) {
       'getTemporaryDirectory' => d.sandbox,
       'getApplicationDocumentsDirectory' => d.path('applications'),
+      'getApplicationSupportDirectory' => d.path('support'),
       _ => throw UnsupportedError('Unexpected path provider call: $call')
     };
   });
@@ -69,6 +71,35 @@ void main() {
     await database.close();
   });
 
+  test('can use custom database directory', () async {
+    final database = SimpleDatabase(driftDatabase(
+      name: 'database',
+      native: DriftNativeOptions(
+        databaseDirectory: getApplicationSupportDirectory,
+      ),
+    ));
+    await database.customSelect('SELECT 1').get();
+
+    expect(sqlite3.tempDirectory, d.sandbox);
+    await d.dir('support', [
+      d.FileDescriptor.binaryMatcher('database.sqlite', anything),
+    ]).validate();
+    await database.close();
+  });
+
+  test('forbids passing custom directory and custom path', () async {
+    expect(
+      () => SimpleDatabase(driftDatabase(
+        name: 'database',
+        native: DriftNativeOptions(
+          databasePath: () async => d.path('my_dir/custom_file'),
+          databaseDirectory: getApplicationSupportDirectory,
+        ),
+      )),
+      throwsAssertionError,
+    );
+  });
+
   test('can use custom temporary directory', () async {
     final database = SimpleDatabase(driftDatabase(
       name: 'database',
@@ -147,6 +178,7 @@ void main() {
       final isolate = await Isolate.spawn((_) {}, '');
       isolate.kill();
 
+      await pumpEventQueue(times: 1);
       expect(await isolate.pingWithTimeout(), false);
     });