split file_viewer into focused sub-widgets

2026-07-13 00:01:07 +02:00
parent 53bc6d5360
commit 2f5a6b4ce0
6 changed files with 512 additions and 479 deletions
@@ -0,0 +1,92 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+import 'dart:math';
+
+enum FileKind { image, svg, pdf, text, video, audio, unknown }
+
+const Set<String> _imageExtensions = {
+  'png',
+  'jpg',
+  'jpeg',
+  'webp',
+  'gif',
+  'bmp',
+  'wbmp',
+};
+
+const Set<String> _videoExtensions = {
+  'mp4',
+  'm4v',
+  'mov',
+  'webm',
+  'mkv',
+  '3gp',
+};
+
+/// ogg/opus/flac are Android-only; iOS init errors fall through to the
+/// "format not supported" message.
+const Set<String> _audioExtensions = {
+  'mp3',
+  'm4a',
+  'aac',
+  'wav',
+  'flac',
+  'ogg',
+  'oga',
+  'opus',
+};
+
+/// Unknown extensions still get a content sniff via [_looksLikeText].
+const Set<String> _textExtensions = {
+  'txt', 'md', 'markdown', 'rst', 'log',
+  'json', 'json5', 'xml', 'yaml', 'yml', 'toml',
+  'csv', 'tsv', 'tab',
+  'ini', 'conf', 'cfg', 'env', 'properties',
+  'html', 'htm', 'xhtml',
+  'css', 'scss', 'sass', 'less',
+  'js', 'mjs', 'cjs', 'ts', 'jsx', 'tsx',
+  'dart', 'java', 'kt', 'kts', 'groovy', 'scala', 'swift',
+  'py', 'rb', 'pl', 'lua', 'r',
+  'go', 'rs', 'zig',
+  'c', 'cpp', 'cc', 'cxx', 'h', 'hpp', 'cs', 'm', 'mm',
+  'php', 'sh', 'bash', 'zsh', 'fish', 'ps1', 'bat', 'cmd',
+  'sql', 'graphql', 'gql',
+  'gitignore', 'gitattributes', 'editorconfig', 'dockerignore',
+  'dockerfile', 'makefile', 'cmake',
+  'tex', 'bib',
+  'srt', 'vtt',
+};
+
+/// Detects the [FileKind] of the file at [path] from its extension, falling
+/// back to an 8 KB content sniff ([_looksLikeText]) for unknown extensions.
+Future<FileKind> detectFileKind(String path) async {
+  final ext = path.split('.').last.toLowerCase();
+  if (_imageExtensions.contains(ext)) return FileKind.image;
+  if (ext == 'svg') return FileKind.svg;
+  if (ext == 'pdf') return FileKind.pdf;
+  if (_videoExtensions.contains(ext)) return FileKind.video;
+  if (_audioExtensions.contains(ext)) return FileKind.audio;
+  if (_textExtensions.contains(ext)) return FileKind.text;
+  if (await _looksLikeText(path)) return FileKind.text;
+  return FileKind.unknown;
+}
+
+/// 8 KB sniff: NUL bytes or non-UTF-8 sequences disqualify.
+Future<bool> _looksLikeText(String path) async {
+  final file = File(path);
+  RandomAccessFile? raf;
+  try {
+    final length = await file.length();
+    if (length == 0) return true;
+    raf = await file.open();
+    final sample = await raf.read(min(length, 8192));
+    if (sample.contains(0)) return false;
+    utf8.decode(sample);
+    return true;
+  } on Object {
+    return false;
+  } finally {
+    await raf?.close();
+  }
+}