Fix archive download when using custom download path on Android.

lib/network/download.dart

@@ -2,6 +2,8 @@ import 'dart:async';
 import 'dart:isolate';
 
 import 'package:flutter/widgets.dart' show ChangeNotifier;
+import 'package:flutter_saf/flutter_saf.dart';
+import 'package:venera/foundation/app.dart';
 import 'package:venera/foundation/appdata.dart';
 import 'package:venera/foundation/comic_source/comic_source.dart';
 import 'package:venera/foundation/comic_type.dart';
@@ -739,11 +741,12 @@ class ArchiveDownloadTask extends DownloadTask {
       path = dir.path;
     }
 
-    var resultFile = File(FilePath.join(path!, "archive.zip"));
+    var archiveFile =
+        File(FilePath.join(App.dataPath, "archive_downloading.zip"));
 
     Log.info("Download", "Downloading $archiveUrl");
 
-    _downloader = FileDownloader(archiveUrl, resultFile.path);
+    _downloader = FileDownloader(archiveUrl, archiveFile.path);
 
     bool isDownloaded = false;
 
@@ -772,22 +775,33 @@ class ArchiveDownloadTask extends DownloadTask {
     }
 
     try {
-      await extractArchive(path!);
+      await _extractArchive(archiveFile.path, path!);
     } catch (e) {
       _setError("Failed to extract archive: $e");
       return;
     }
 
-    await resultFile.deleteIgnoreError();
+    await archiveFile.deleteIgnoreError();
 
     LocalManager().completeTask(this);
   }
 
-  static Future<void> extractArchive(String path) async {
-    var resultFile = FilePath.join(path, "archive.zip");
+  static Future<void> _extractArchive(String archive, String outDir) async {
+    var out = Directory(outDir);
+    if (out is AndroidDirectory) {
+      // Saf directory can't be accessed by native code.
+      var cacheDir = FilePath.join(App.cachePath, "archive_downloading");
+      Directory(cacheDir).forceCreateSync();
       await Isolate.run(() {
-      ZipFile.openAndExtract(resultFile, path);
+        ZipFile.openAndExtract(archive, cacheDir);
       });
+      await copyDirectoryIsolate(Directory(cacheDir), Directory(outDir));
+      await Directory(cacheDir).deleteIgnoreError(recursive: true);
+    } else {
+      await Isolate.run(() {
+        ZipFile.openAndExtract(archive, outDir);
+      });
+    }
   }
 
   @override

lib/utils/io.dart

@@ -40,6 +40,7 @@ extension FileSystemEntityExt on FileSystemEntity {
     return p.basename(path);
   }
 
+  /// Delete the file or directory and ignore errors.
   Future<void> deleteIgnoreError({bool recursive = false}) async {
     try {
       await delete(recursive: recursive);
@@ -48,12 +49,14 @@ extension FileSystemEntityExt on FileSystemEntity {
     }
   }
 
+  /// Delete the file or directory if it exists.
   Future<void> deleteIfExists({bool recursive = false}) async {
     if (existsSync()) {
       await delete(recursive: recursive);
     }
   }
 
+  /// Delete the file or directory if it exists.
   void deleteIfExistsSync({bool recursive = false}) {
     if (existsSync()) {
       deleteSync(recursive: recursive);
@@ -74,12 +77,14 @@ extension FileExtension on File {
     await newFile.writeAsBytes(await readAsBytes());
   }
 
+  /// Get the base name of the file without the extension.
   String get basenameWithoutExt {
     return p.basenameWithoutExtension(path);
   }
 }
 
 extension DirectoryExtension on Directory {
+  /// Calculate the size of the directory.
   Future<int> get size async {
     if (!existsSync()) return 0;
     int total = 0;
@@ -91,6 +96,7 @@ extension DirectoryExtension on Directory {
     return total;
   }
 
+  /// Change the base name of the directory.
   Directory renameX(String newName) {
     newName = sanitizeFileName(newName);
     return renameSync(path.replaceLast(name, newName));
@@ -100,6 +106,7 @@ extension DirectoryExtension on Directory {
     return File(FilePath.join(path, name));
   }
 
+  /// Delete the contents of the directory.
   void deleteContentsSync({recursive = true}) {
     if (!existsSync()) return;
     for (var f in listSync()) {
@@ -107,14 +114,24 @@ extension DirectoryExtension on Directory {
     }
   }
 
+  /// Delete the contents of the directory.
   Future<void> deleteContents({recursive = true}) async {
     if (!existsSync()) return;
     for (var f in listSync()) {
       await f.deleteIfExists(recursive: recursive);
     }
   }
+
+  /// Create the directory. If the directory already exists, delete it first.
+  void forceCreateSync() {
+    if (existsSync()) {
+      deleteSync(recursive: true);
+    }
+    createSync(recursive: true);
+  }
 }
 
+/// Sanitize the file name. Remove invalid characters and trim the file name.
 String sanitizeFileName(String fileName) {
   if (fileName.endsWith('.')) {
     fileName = fileName.substring(0, fileName.length - 1);
@@ -157,6 +174,8 @@ Future<void> copyDirectory(Directory source, Directory destination) async {
   }
 }
 
+/// Copy the **contents** of the source directory to the destination directory.
+/// This function is executed in an isolate to prevent the UI from freezing.
 Future<void> copyDirectoryIsolate(
     Directory source, Directory destination) async {
   await Isolate.run(() => overrideIO(() => copyDirectory(source, destination)));