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fix wal save crash and handle missing directory #4216

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fix wal save crash and handle missing directory #4216

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c542857
fix wal save crash and handle missing directory
krushnarout Jan 13, 2026
9f90dc2
fix error handling
krushnarout Jan 13, 2026
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67 changes: 41 additions & 26 deletions app/lib/services/wals/local_wal_sync.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,8 @@ class LocalWalSyncImpl implements LocalWalSync {
Timer? _chunkingTimer;
Timer? _flushingTimer;

bool _isFlushing = false;

IWalSyncListener listener;

int _framesPerSecond = 100;
Expand Down Expand Up @@ -199,39 +201,52 @@ class LocalWalSyncImpl implements LocalWalSync {
}

Future _flush() async {
Logger.debug("_flushing");
for (var i = 0; i < _wals.length; i++) {
final wal = _wals[i];

if (wal.storage == WalStorage.mem) {
String? filePath = await Wal.getFilePath(wal.getFileName());
if (filePath == null) {
throw Exception('Flushing to storage failed. Cannot get file path.');
}
if (_isFlushing) {
Logger.debug("LocalWalSync: Flush already in progress, skipping");
return;
}
_isFlushing = true;

List<int> data = [];
for (int i = 0; i < wal.data.length; i++) {
var frame = wal.data[i].sublist(3);
try {
Logger.debug("_flushing");
for (var i = 0; i < _wals.length; i++) {
final wal = _wals[i];

if (wal.storage == WalStorage.mem) {
String? filePath = await Wal.getFilePath(wal.getFileName());
if (filePath == null) {
throw Exception('Flushing to storage failed. Cannot get file path.');
}

final byteFrame = ByteData(frame.length);
for (int i = 0; i < frame.length; i++) {
byteFrame.setUint8(i, frame[i]);
List<int> data = [];
for (int i = 0; i < wal.data.length; i++) {
var frame = wal.data[i].sublist(3);

final byteFrame = ByteData(frame.length);
for (int i = 0; i < frame.length; i++) {
byteFrame.setUint8(i, frame[i]);
}
data.addAll(Uint32List.fromList([frame.length]).buffer.asUint8List());
data.addAll(byteFrame.buffer.asUint8List());
}
data.addAll(Uint32List.fromList([frame.length]).buffer.asUint8List());
data.addAll(byteFrame.buffer.asUint8List());
}
final file = File(filePath);
await file.writeAsBytes(data);
wal.filePath = wal.getFileName();
wal.storage = WalStorage.disk;
final file = File(filePath);
await file.writeAsBytes(data);
wal.filePath = wal.getFileName();
wal.storage = WalStorage.disk;

Logger.debug("_flush file ${wal.filePath}");
Logger.debug("_flush file ${wal.filePath}");

_wals[i] = wal;
_wals[i] = wal;
}
}
}

await _saveWalsToFile();
await _saveWalsToFile();
} catch (e) {
Logger.debug("LocalWalSync: Error during flush: $e");
rethrow;
} finally {
_isFlushing = false;
}
}

Future<void> _saveWalsToFile() async {
Expand Down
55 changes: 38 additions & 17 deletions app/lib/utils/wal_file_manager.dart
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Original file line number Diff line number Diff line change
@@ -1,3 +1,4 @@
import 'dart:async';
import 'dart:convert';
import 'dart:io';

Expand All @@ -18,6 +19,7 @@ class WalFileManager {

static File? _walFile;
static File? _walBackupFile;
static Future<void> _lastSaveFuture = Future.value();

static Future<void> init() async {
final directory =
Expand Down Expand Up @@ -53,28 +55,47 @@ class WalFileManager {
}

static Future<bool> saveWals(List<Wal> wals) async {
if (_walFile == null) {
await init();
}
final previousFuture = _lastSaveFuture;
final completer = Completer<void>();
_lastSaveFuture = completer.future;

if (_walFile == null) {
Logger.debug('WAL file is null, cannot save');
return false;
}
await previousFuture.catchError((_) {});

await _createBackup();
try {
if (_walFile == null) {
await init();
}

final jsonData = {
'version': 1,
'timestamp': DateTime.now().millisecondsSinceEpoch,
'wals': wals.map((wal) => wal.toJson()).toList(),
};
if (_walFile == null) {
Logger.debug('WAL file is null, cannot save');
return false;
}

final jsonString = jsonEncode(jsonData);
await _walFile!.writeAsString(jsonString);
if (!_walFile!.parent.existsSync()) {
try {
await _walFile!.parent.create(recursive: true);
} catch (e) {
Logger.debug('Failed to create WAL directory: $e');
return false;
}
}

await _createBackup();

final jsonData = {
'version': 1,
'timestamp': DateTime.now().millisecondsSinceEpoch,
'wals': wals.map((wal) => wal.toJson()).toList(),
};

Logger.debug('Successfully saved ${wals.length} WALs to file');
return true;
final jsonString = jsonEncode(jsonData);
await _walFile!.writeAsString(jsonString);

Logger.debug('Successfully saved ${wals.length} WALs to file');
return true;
} finally {
completer.complete();
}
}

static Future<void> _createBackup() async {
Expand Down