diff --git a/lib/foundation/cache_manager.dart b/lib/foundation/cache_manager.dart
index 9d7f42e6..ac85da39 100644
--- a/lib/foundation/cache_manager.dart
+++ b/lib/foundation/cache_manager.dart
@@ -1,7 +1,7 @@
 import 'dart:io';
+import 'dart:typed_data';
 
 import 'package:crypto/crypto.dart';
-import 'package:flutter/foundation.dart';
 import 'package:pica_comic/foundation/app.dart';
 import 'package:pica_comic/tools/io_extensions.dart';
 import 'package:sqlite3/sqlite3.dart';
@@ -44,16 +44,32 @@ class CacheManager {
     } catch (e) {
       // ignore
     }
-    compute((path) => Directory(path).size, cachePath)
-        .then((value) => _currentSize = value);
+    _initCurrentSize();
   }
 
   factory CacheManager() => instance ??= CacheManager._create();
 
+  /// 异步初始化目录大小，使用安全的 _calcDirSize 避免 isolate OOM
+  Future<void> _initCurrentSize() async {
+    try {
+      _currentSize = await _calcDirSize(cachePath);
+    } catch (e) {
+      // 初始化失败回退为 0
+      _currentSize = 0;
+    }
+  }
+
   /// set cache size limit in MB
+  /// 修改 4：缩小限制时立即触发清理
   void setLimitSize(int size){
-    _limitSize = size * 1024 * 1024;
-  }
+      _limitSize = size * 1024 * 1024;
+      if (_currentSize != null && _currentSize! > _limitSize) {
+        checkCache().catchError((_) {
+          // ignore: checkCache 失败不影响 setLimitSize，下次写入或手动触发会重试
+        });
+      }
+    }
+
 
   void setType(String key, String? type){
     _db.execute('''
@@ -75,28 +91,38 @@ class CacheManager {
   }
 
   Future<void> writeCache(String key, Uint8List data, [int duration = 7 * 24 * 60 * 60 * 1000]) async{
-    this.dir++;
-    this.dir %= 100;
-    var dir = this.dir;
-    var name = md5.convert(Uint8List.fromList(key.codeUnits)).toString();
-    var file = File('$cachePath/$dir/$name');
-    while(await file.exists()){
-      name = md5.convert(Uint8List.fromList(name.codeUnits)).toString();
-      file = File('$cachePath/$dir/$name');
-    }
+  this.dir++;
+  this.dir %= 100;
+  var dir = this.dir;
+  var name = md5.convert(Uint8List.fromList(key.codeUnits)).toString();
+  var file = File('$cachePath/$dir/$name');
+  while(await file.exists()){
+    name = md5.convert(Uint8List.fromList(name.codeUnits)).toString();
+    file = File('$cachePath/$dir/$name');
+  }
+
+  // 先写入 DB 记录，再写文件：确保 DB 是文件的权威来源
+  var expires = DateTime.now().millisecondsSinceEpoch + duration;
+  _db.execute('''
+    INSERT OR REPLACE INTO cache (key, dir, name, expires) VALUES (?, ?, ?, ?)
+  ''', [key, dir.toString(), name, expires]);
+
+  try {
     await file.create(recursive: true);
     await file.writeAsBytes(data);
-    var expires = DateTime.now().millisecondsSinceEpoch + duration;
-    _db.execute('''
-      INSERT OR REPLACE INTO cache (key, dir, name, expires) VALUES (?, ?, ?, ?)
-    ''', [key, dir.toString(), name, expires]);
-    if(_currentSize != null) {
-      _currentSize = _currentSize! + data.length;
-    }
-    if(_currentSize != null && _currentSize! > _limitSize){
+  } catch (e) {
+    // 文件写入失败，回滚 DB 记录，防止 DB 中存在无对应文件的记录
+    _db.execute('DELETE FROM cache WHERE key = ?', [key]);
+    rethrow;
+  }
+
+  if (_currentSize != null) {
+    _currentSize = _currentSize! + data.length;
+    if (_currentSize! > _limitSize) {
       await checkCache();
     }
   }
+}
 
   Future<CachingFile> openWrite(String key) async{
     this.dir++;
@@ -120,113 +146,163 @@ class CacheManager {
     if(res.isEmpty){
       return null;
     }
-    var row = res.first;
-    var dir = row[1] as String;
-    var name = row[2] as String;
-    var file = File('$cachePath/$dir/$name');
-    if(await file.exists()){
-      return file.path;
+    try {
+      var row = res.first;
+      var dir = row[1] as String;
+      var name = row[2] as String;
+      var file = File('$cachePath/$dir/$name');
+      if(await file.exists()){
+        return file.path;
+      }
+    } catch (_) {
+      // 权限不足或文件系统异常时返回 null
     }
     return null;
   }
 
   bool _isChecking = false;
 
+  /// 修改 1：移除 compute，使用 _calcDirSize 避免 isolate OOM；加 try-finally 防止 _isChecking 锁死；
+  /// 添加 anyDeleted 防止空转死循环
   Future<void> checkCache() async{
     if(_isChecking){
       return;
     }
     _isChecking = true;
-    var res = _db.select('''
-      SELECT * FROM cache
-      WHERE expires < ?
-    ''', [DateTime.now().millisecondsSinceEpoch]);
-    for(var row in res){
-      var dir = row[1] as String;
-      var name = row[2] as String;
-      var file = File('$cachePath/$dir/$name');
-      if(await file.exists()){
-        await file.delete();
+    try {
+      // 第一步：清理已过期的缓存条目
+      var res = _db.select('''
+        SELECT * FROM cache
+        WHERE expires < ?
+      ''', [DateTime.now().millisecondsSinceEpoch]);
+      for(var row in res){
+        try {
+          var dir = row[1] as String;
+          var name = row[2] as String;
+          var file = File('$cachePath/$dir/$name');
+          if(await file.exists()){
+            await file.delete();
+          }
+        } catch (_) {
+          // 权限不足或文件被外部删除时跳过
+        }
       }
+      _db.execute('''
+        DELETE FROM cache
+        WHERE expires < ?
+      ''', [DateTime.now().millisecondsSinceEpoch]);
+
+      // 第二步：获取当前条目数
+      // int count = 0;
+      // var res2 = _db.select('SELECT COUNT(*) FROM cache');
+      // if(res2.isNotEmpty){
+      //   count = res2.first[0] as int;
+      // }
+
+      // 第三步：在主 isolate 中直接计算目录大小（移除 compute，避免 isolate OOM）
+      _currentSize = await _calcDirSize(cachePath);
+
+      // 第四步：循环清理直到满足限制
+      // while (_currentSize! > _limitSize || count > 2000) {
+      while (_currentSize! > _limitSize) {
+        var res3 = _db.select('''
+          SELECT * FROM cache
+          ORDER BY expires ASC
+          LIMIT 10
+        ''');
+        bool anyDeleted = false;
+        for(var row in res3){
+          try {
+            var key = row[0] as String;
+            var dir = row[1] as String;
+            var name = row[2] as String;
+            var file = File('$cachePath/$dir/$name');
+            if(await file.exists()){
+              var size = await file.length();
+              await file.delete();
+              _db.execute('DELETE FROM cache WHERE key = ?', [key]);
+              _currentSize = _currentSize! - size;
+              anyDeleted = true;
+              // if(_currentSize! <= _limitSize && count - 1 <= 2000){
+              if(_currentSize! <= _limitSize){
+                break;
+              }
+            } else {
+              _db.execute('DELETE FROM cache WHERE key = ?', [key]);
+              anyDeleted = true;
+            }
+          } catch (_) { 
+            //// 权限不足或文件操作异常时跳过当前条目，继续处理下一个
+          }
+          // count--;
+        }
+        if (!anyDeleted) {
+          break; // 防止死循环：数据库中还有记录但文件都已不存在
+        }
+      }
+    } finally {
+      _isChecking = false;
     }
-    _db.execute('''
-      DELETE FROM cache
-      WHERE expires < ?
-    ''', [DateTime.now().millisecondsSinceEpoch]);
+  }
 
-    int count = 0;
-    var res2 = _db.select('''
-      SELECT COUNT(*) FROM cache
-    ''');
-    if(res2.isNotEmpty){
-      count = res2.first[0] as int;
+  /// 修改 1：在主 isolate 中分批计算目录大小，避免 listSync(recursive: true) OOM
+  Future<int> _calcDirSize(String path) async {
+    int total = 0;
+    final dir = Directory(path);
+    if (!dir.existsSync()) return 0;
+    final List<FileSystemEntity> entries = dir.listSync(followLinks: false);//防止目录包含软链接 / 符号链接（指向自身 / 上级目录），递归无限执行
+    for (final entity in entries) {
+      try {
+        if (entity is File) {
+          total += await entity.length();
+        } else if (entity is Directory) {
+          total += await _calcDirSize(entity.path);
+        }
+      } catch (_) {
+        // 权限不足或文件被删除时跳过
+      }
     }
+    return total;
+  }
 
-    compute((path) => Directory(path).size, cachePath)
-        .then((value) => _currentSize = value);
-
-    while((_currentSize != null && _currentSize! > _limitSize) ||  count > 2000){
+  Future<void> delete(String key) async{
       var res = _db.select('''
         SELECT * FROM cache
-        ORDER BY expires ASC
-        limit 10
-      ''');
-      for(var row in res){
-        var key = row[0] as String;
-        var dir = row[1] as String;
-        var name = row[2] as String;
-        var file = File('$cachePath/$dir/$name');
+        WHERE key = ?
+      ''', [key]);
+      if(res.isEmpty){
+        return;
+      }
+      var row = res.first;
+      var dir = row[1] as String;
+      var name = row[2] as String;
+      var file = File('$cachePath/$dir/$name');
+  
+      try {
         if(await file.exists()){
-          var size = await file.length();
+          var fileSize = await file.length();
           await file.delete();
-          _db.execute('''
-            DELETE FROM cache
-            WHERE key = ?
-          ''', [key]);
-          _currentSize = _currentSize! - size;
-          if(_currentSize! <= _limitSize){
-            break;
+          // 只有文件真正删除成功，才清理 DB 和扣减大小
+          _db.execute('DELETE FROM cache WHERE key = ?', [key]);
+          if (_currentSize != null) {
+            _currentSize = _currentSize! - fileSize;
           }
         } else {
-          _db.execute('''
-            DELETE FROM cache
-            WHERE key = ?
-          ''', [key]);
+          // 文件已被外部删除，只清理 DB 记录
+          _db.execute('DELETE FROM cache WHERE key = ?', [key]);
         }
-        count--;
+      } catch (_) {
+        // 文件操作失败，保留 DB 记录不删除
+        // 下次 delete() 或 checkCache() 会重试
       }
     }
-    _isChecking = false;
-  }
-
-  Future<void> delete(String key) async{
-    var res = _db.select('''
-      SELECT * FROM cache
-      WHERE key = ?
-    ''', [key]);
-    if(res.isEmpty){
-      return;
-    }
-    var row = res.first;
-    var dir = row[1] as String;
-    var name = row[2] as String;
-    var file = File('$cachePath/$dir/$name');
-    var fileSize = 0;
-    if(await file.exists()){
-      fileSize = await file.length();
-      await file.delete();
-    }
-    _db.execute('''
-      DELETE FROM cache
-      WHERE key = ?
-    ''', [key]);
-    if(_currentSize != null) {
-      _currentSize = _currentSize! - fileSize;
-    }
-  }
 
   Future<void> clear() async {
-    await Directory(cachePath).delete(recursive: true);
+    try {
+      await Directory(cachePath).delete(recursive: true);
+    } catch (_) {
+      // 权限不足时忽略
+    }
     Directory(cachePath).createSync(recursive: true);
     _db.execute('''
       DELETE FROM cache
@@ -245,24 +321,27 @@ class CacheManager {
       var name = row[2] as String;
       var file = File('$cachePath/$dir/$name');
       var fileSize = 0;
-      if(await file.exists()){
-        fileSize = await file.length();
-        try {
-          await file.delete();
+      try {
+        if(await file.exists()){
+          fileSize = await file.length();
         }
-        finally {}
+      } catch (_) {
+        // 权限不足或文件被外部删除时跳过
+        fileSize = 0;
       }
+      await file.deleteIgnoreError();
       _db.execute('''
         DELETE FROM cache
         WHERE key = ?
       ''', [key]);
-      if(_currentSize != null) {
+      if (_currentSize != null) {
         _currentSize = _currentSize! - fileSize;
       }
     }
   }
 }
 
+/// 修改 6：新增 _writtenBytes 追踪，修改 close()/cancel()/reset() 同步 _currentSize
 class CachingFile{
   CachingFile._(this.key, this.dir, this.name, this.file);
 
@@ -276,29 +355,56 @@ class CachingFile{
 
   final List<int> _buffer = [];
 
+  int _writtenBytes = 0; // 跟踪已写入磁盘的字节数
+
   Future<void> writeBytes(List<int> data) async{
     _buffer.addAll(data);
     if(_buffer.length > 1024 * 1024){
       await file.writeAsBytes(_buffer, mode: FileMode.append);
+      _writtenBytes += _buffer.length;
       _buffer.clear();
     }
   }
 
-  Future<void> close() async{
-    if(_buffer.isNotEmpty){
-      await file.writeAsBytes(_buffer, mode: FileMode.append);
+Future<void> close() async{
+  if(_buffer.isNotEmpty){
+    await file.writeAsBytes(_buffer, mode: FileMode.append);
+    _writtenBytes += _buffer.length;
+    _buffer.clear();
+  }
+  CacheManager()._db.execute('''
+    INSERT OR REPLACE INTO cache (key, dir, name, expires) VALUES (?, ?, ?, ?)
+  ''', [key, dir, name, DateTime.now().millisecondsSinceEpoch + 7 * 24 * 60 * 60 * 1000]);
+  // 追踪写入的缓存大小
+  final cm = CacheManager();
+  if (cm._currentSize != null) {
+    cm._currentSize = cm._currentSize! + _writtenBytes;
+    if (cm._currentSize! > cm._limitSize) {
+      await cm.checkCache();
     }
-    CacheManager()._db.execute('''
-      INSERT OR REPLACE INTO cache (key, dir, name, expires) VALUES (?, ?, ?, ?)
-    ''', [key, dir, name, DateTime.now().millisecondsSinceEpoch + 7 * 24 * 60 * 60 * 1000]);
-    await CacheManager().checkCache();
   }
+}
 
   Future<void> cancel() async{
+    // 如果已写入部分数据且 _currentSize 已追踪，需要扣减
+    if (_writtenBytes > 0) {
+      final cm = CacheManager();
+      if (cm._currentSize != null) {
+        cm._currentSize = cm._currentSize! - _writtenBytes;
+      }
+    }
     await file.deleteIgnoreError();
   }
 
   void reset() {
+    // 重置前扣减已追踪的大小
+    if (_writtenBytes > 0) {
+      final cm = CacheManager();
+      if (cm._currentSize != null) {
+        cm._currentSize = cm._currentSize! - _writtenBytes;
+      }
+    }
+    _writtenBytes = 0;
     _buffer.clear();
     if(file.existsSync()) {
       file.deleteSync();