Draft: chore: use existing open file in Frame Helper

hive/lib/src/backend/vm/storage_backend_vm.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:developer';
 import 'dart:io';
 
 import 'package:hive/hive.dart';
@@ -38,7 +39,7 @@ class StorageBackendVm extends StorageBackend {
 
   /// Not part of public API
   @visibleForTesting
-  late RandomAccessFile lockRaf;
+  RandomAccessFile? lockRaf;
 
   /// Not part of public API
   @visibleForTesting
@@ -78,28 +79,39 @@ class StorageBackendVm extends StorageBackend {
       TypeRegistry registry, Keystore keystore, bool lazy) async {
     this.registry = registry;
 
-    lockRaf = await _lockFile.open(mode: FileMode.write);
     if ((Hive as HiveImpl).useLocks) {
+      final lockRaf = this.lockRaf = await _lockFile.open(mode: FileMode.write);
       await lockRaf.lock();
     }
 
-    int recoveryOffset;
-    if (!lazy) {
-      recoveryOffset =
-          await _frameHelper.framesFromFile(path, keystore, registry, _cipher);
-    } else {
-      recoveryOffset = await _frameHelper.keysFromFile(path, keystore, _cipher);
-    }
-
-    if (recoveryOffset != -1) {
-      if (_crashRecovery) {
-        print('Recovering corrupted box.');
-        await writeRaf.truncate(recoveryOffset);
-        await writeRaf.setPosition(recoveryOffset);
-        writeOffset = recoveryOffset;
+    try {
+      int recoveryOffset;
+      if (!lazy) {
+        recoveryOffset = await _frameHelper.framesFromFile(
+            readRaf, keystore, registry, _cipher);
       } else {
-        throw HiveError('Wrong checksum in hive file. Box may be corrupted.');
+        recoveryOffset =
+            await _frameHelper.keysFromFile(readRaf, keystore, _cipher);
+      }
+
+      if (recoveryOffset != -1) {
+        if (_crashRecovery) {
+          print('Recovering corrupted box.');
+          await writeRaf.truncate(recoveryOffset);
+          await writeRaf.setPosition(recoveryOffset);
+          writeOffset = recoveryOffset;
+        } else {
+          throw HiveError('Wrong checksum in hive file. Box may be corrupted.');
+        }
       }
+    } catch (e, s) {
+      log(
+        'Error checking hive recovery offset',
+        error: e,
+        stackTrace: s,
+        name: 'hive',
+      );
+      rethrow;
     }
   }
 
@@ -217,8 +229,10 @@ class StorageBackendVm extends StorageBackend {
     await readRaf.close();
     await writeRaf.close();
 
-    await lockRaf.close();
-    await _lockFile.delete();
+    await lockRaf?.close();
+    if (await _lockFile.exists()) {
+      await _lockFile.delete();
+    }
   }
 
   @override

hive/lib/src/io/frame_io_helper.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:io';
 import 'dart:typed_data';
 
@@ -12,34 +13,44 @@ import 'package:meta/meta.dart';
 /// Not part of public API
 class FrameIoHelper extends FrameHelper {
   /// Not part of public API
+  ///
+  /// helps allowing to override this method in tests
   @visibleForTesting
-  Future<RandomAccessFile> openFile(String path) {
-    return File(path).open();
+  FutureOr<RandomAccessFile> overridableRAF(RandomAccessFile raf) {
+    return raf;
   }
 
   /// Not part of public API
+  ///
+  /// helps allowing to override this method in tests
   @visibleForTesting
-  Future<List<int>> readFile(String path) {
-    return File(path).readAsBytes();
+  Future<Uint8List> overridableReadFile(RandomAccessFile raf) async {
+    final previousPosition = await raf.position(); // likely 0 in any case
+
+    final length = await raf.length();
+    final bytes = await raf.read(length);
+
+    await raf.setPosition(previousPosition);
+
+    return bytes;
   }
 
   /// Not part of public API
   Future<int> keysFromFile(
-      String path, Keystore keystore, HiveCipher? cipher) async {
-    var raf = await openFile(path);
-    var fileReader = BufferedFileReader(raf);
-    try {
-      return await _KeyReader(fileReader).readKeys(keystore, cipher);
-    } finally {
-      await raf.close();
-    }
+      RandomAccessFile raf, Keystore keystore, HiveCipher? cipher) async {
+    // only used for testing override
+    final file = await overridableRAF(raf);
+    final fileReader = BufferedFileReader(file);
+
+    return await _KeyReader(fileReader).readKeys(keystore, cipher);
   }
 
   /// Not part of public API
-  Future<int> framesFromFile(String path, Keystore keystore,
+  Future<int> framesFromFile(RandomAccessFile raf, Keystore keystore,
       TypeRegistry registry, HiveCipher? cipher) async {
-    var bytes = await readFile(path);
-    return framesFromBytes(bytes as Uint8List, keystore, registry, cipher);
+    // only used for testing override
+    final bytes = await overridableReadFile(raf);
+    return framesFromBytes(bytes, keystore, registry, cipher);
   }
 }
 

hive/test/tests/backend/memory/random_access_buffer_test.dart

@@ -4,7 +4,6 @@ import 'package:hive/src/binary/frame.dart';
 import 'package:hive/src/registry/type_registry_impl.dart';
 import 'package:test/test.dart';
 
-
 void main() {
   group('RandomAccessBuffer', () {
     test('empty random access buffer', () {

hive/test/tests/backend/vm/storage_backend_vm_test.dart

@@ -252,8 +252,7 @@ void main() {
             .thenAnswer((i) => Future.value(writeRaf));
         when(() => writeRaf.writeFrom(bytes))
             .thenAnswer((i) => Future.value(writeRaf));
-        when(() => writeRaf.flush())
-            .thenAnswer((i) => Future.value(writeRaf));
+        when(() => writeRaf.flush()).thenAnswer((i) => Future.value(writeRaf));
 
         var backend = _getBackend(writeRaf: writeRaf)
           // The registry needs to be initialized before writing values, and

hive/test/tests/io/frame_io_helper_test.dart

@@ -23,12 +23,12 @@ class _FrameIoHelperTest extends FrameIoHelper {
   _FrameIoHelperTest(this.bytes);
 
   @override
-  Future<RandomAccessFile> openFile(String path) async {
+  Future<RandomAccessFile> overridableRAF(RandomAccessFile raf) async {
     return getTempRaf(bytes);
   }
 
   @override
-  Future<Uint8List> readFile(String path) async {
+  Future<Uint8List> overridableReadFile(RandomAccessFile raf) async {
     return bytes;
   }
 }
@@ -39,8 +39,8 @@ void main() {
       test('frame', () async {
         var keystore = Keystore.debug();
         var ioHelper = _FrameIoHelperTest(_getBytes(frameBytes));
-        var recoveryOffset =
-            await ioHelper.keysFromFile('null', keystore, null);
+        var recoveryOffset = await ioHelper.keysFromFile(
+            await getTempRaf(const []), keystore, null);
         expect(recoveryOffset, -1);
 
         var testKeystore = Keystore.debug(
@@ -53,8 +53,8 @@ void main() {
       test('encrypted', () async {
         var keystore = Keystore.debug();
         var ioHelper = _FrameIoHelperTest(_getBytes(frameBytesEncrypted));
-        var recoveryOffset =
-            await ioHelper.keysFromFile('null', keystore, testCipher);
+        var recoveryOffset = await ioHelper.keysFromFile(
+            await getTempRaf(const []), keystore, testCipher);
         expect(recoveryOffset, -1);
 
         var testKeystore = Keystore.debug(
@@ -73,8 +73,8 @@ void main() {
       test('frame', () async {
         var keystore = Keystore.debug();
         var ioHelper = _FrameIoHelperTest(_getBytes(frameBytes));
-        var recoveryOffset =
-            await ioHelper.framesFromFile('null', keystore, testRegistry, null);
+        var recoveryOffset = await ioHelper.framesFromFile(
+            await getTempRaf(const []), keystore, testRegistry, null);
         expect(recoveryOffset, -1);
 
         var testKeystore = Keystore.debug(
@@ -88,7 +88,7 @@ void main() {
         var keystore = Keystore.debug();
         var ioHelper = _FrameIoHelperTest(_getBytes(frameBytesEncrypted));
         var recoveryOffset = await ioHelper.framesFromFile(
-            'null', keystore, testRegistry, testCipher);
+            await getTempRaf(const []), keystore, testRegistry, testCipher);
         expect(recoveryOffset, -1);
 
         var testKeystore = Keystore.debug(