Flutter文件扩展名处理插件file_ext的使用

Flutter文件扩展名处理插件file_ext的使用

特性

该插件提供了异步和同步扩展方法来：

• 循环遍历文件系统实体（通过多个目录中的多个Glob模式过滤）并调用用户定义的函数。
• 循环遍历所有基于内存的文件系统，并调用用户定义的函数（适用于单元测试）。
• 循环遍历来自标准输入的行并调用用户定义的函数或读取整个标准输入。
• 文件路径API扩展：
  • adjust() - 将所有路径分隔符转换为操作系统特定的样式。
  • toPosix() - 将所有路径分隔符转换为POSIX样式。
  • getFullPath() - 类似于canonicalize()，但保留字母大小写。
  • isHidden() - 检查给定文件名是否以点开始，或者路径是否包含以点开始的子目录（但不仅限于点）。
  • isPath() - 检查给定字符串是否包含目录组件。

使用

请参见下面的示例代码。所有示例代码文件都在example子目录下。

// Copyright (c) 2022-2023, Alexander Iurovetski
// All rights reserved under MIT license (see LICENSE file)

import 'dart:io';

import 'package:file/file.dart';
import 'package:file/local.dart';
import 'package:file_ext/file_ext.dart';
import 'package:glob/glob.dart';
import 'package:intl/intl.dart';
import 'package:loop_visitor/loop_visitor.dart';
import 'package:parse_args/parse_args.dart';
import 'package:thin_logger/thin_logger.dart';

/// A type for the argument parsing callback functions
///
typedef ParseArgsHandler = void Function(String);

/// Application
///
class Options {
  static const appName = 'file_ext_example';

  /// Count findings only
  ///
  var isCountOnly = false;

  /// Synchronous call flag
  ///
  var isSync = false;

  /// Logger
  ///
  final Logger logger = Logger();

  /// FileSystem
  ///
  final FileSystem fileSystem;

  /// All filters
  ///
  final List<Glob> filters = [];

  /// FileList flags
  ///
  var flags = 0;

  /// Directory to start in
  ///
  final List<String> roots = [];

  /// Entity types to consider
  ///
  final List<FileSystemEntityType> types = [];

  /// The actual usage
  ///
  Options(this.fileSystem);

  void parse(List<String> args) {
    var optDefs = '''
      |?,h,help|q,quiet|v,verbose|a,all|d,dir::
      |c,count|L,follow|s,sync|t,type:|::?
    ''';

    var opts = parseArgs(optDefs, args);
    logger.levelFromFlags(isQuiet: opts.isSet('q'), isVerbose: opts.isSet('v'));

    if (opts.isSet('?')) {
      printUsage();
    }

    isCountOnly = opts.isSet('c');
    isSync = opts.isSet('s');

    flags = 0;

    if (!opts.isSet('L')) {
      flags |= FileSystemExt.followLinks;
    }

    if (opts.isSet('a')) {
      flags |= FileSystemExt.allowHidden;
    }

    final typeStr = opts.getStrValue('t')?.toLowerCase();

    if ((typeStr == null) || typeStr.isEmpty || typeStr.contains('d')) {
      types.add(FileSystemEntityType.directory);
    }

    if ((typeStr == null) || typeStr.isEmpty || typeStr.contains('f')) {
      types.add(FileSystemEntityType.file);
    }

    if ((typeStr == null) || typeStr.isEmpty || typeStr.contains('l')) {
      types.add(FileSystemEntityType.link);
    }

    roots.addAll(opts.getStrValues('d'));
    filters.addAll(opts.getGlobValues(''));
  }
}

/// Application singleton
///
final Options opt = Options(LocalFileSystem());

/// Run single filter
///
Never printUsage() {
  opt.logger.info('''
USAGE:

${Options.appName} [OPTIONS]

OPTIONS:

-d, dir DIR   - directory to start in (default: current)
-c,count      - print count only
-L,follow     - expand symbolic links
-s,sync       - fetch synchronously (blocking mode)
-t,type TYPES - entries to fetch (default - all):
                d - directory
                f - file
                l - link
ARGUMENTS:

One or more glob patterns

EXAMPLES:

${Options.appName} -d /home/user/Downloads -type f ../Documents/**.{doc,docx} *.txt
''');

  exit(1);
}

/// Entry point
///
void main(List<String> args) async {
  opt.parse(args);

  var count = 0;

  if (opt.isSync) {
    opt.fileSystem.forEachEntitySync(
        roots: opt.roots,
        filters: opt.filters,
        flags: opt.flags,
        types: opt.types,
        onEntity: (fileSystem, entity, stat) {
          if ((entity == null) || (stat == null)) {
            return VisitResult.take; // continue
          }
          if (opt.isCountOnly) {
            ++count;
          } else {
            var path = fileSystem.path.adjustTrailingSeparator(
                entity.path, stat.type,
                isAppend: true);
            if (stat.type == FileSystemEntityType.link) {
              path += ' -> ${fileSystem.file(path).resolveSymbolicLinksSync()}';
            }
            opt.logger.out(path);
          }
          return VisitResult.take; // continue
        },
        onException: (fileSystem, entity, stat, exception, stackTrace) {
          opt.logger.error(exception.toString());
          return VisitResult.take; // continue
        });
  } else {
    await opt.fileSystem.forEachEntity(
        roots: opt.roots,
        filters: opt.filters,
        flags: opt.flags,
        types: opt.types,
        onEntity: (fileSystem, entity, stat) async {
          if ((entity == null) || (stat == null)) {
            return VisitResult.take; // continue
          }
          if (opt.isCountOnly) {
            ++count;
          } else {
            var path = opt.fileSystem.path.adjustTrailingSeparator(
                entity.path, stat.type,
                isAppend: true);
            if (stat.type == FileSystemEntityType.link) {
              path += ' -> ${fileSystem.file(path).resolveSymbolicLinksSync()}';
            }
            opt.logger.out(path);
          }
          return VisitResult.take; // continue
        },
        onException: (fileSystem, entity, stat, exception, stackTrace) async {
          opt.logger.error(exception.toString());
          return VisitResult.take; // continue
        });
  }

  if (opt.isCountOnly) {
    final value = NumberFormat().format(count);
    final units = (count == 1 ? 'entry' : 'entries');
    opt.logger.out('$value $units found');
  }
}