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Source file src/io/fs/readdir.go

Documentation: io/fs

     1  // Copyright 2020 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package fs
     6  
     7  import (
     8  	"errors"
     9  	"sort"
    10  )
    11  
    12  // ReadDirFS is the interface implemented by a file system
    13  // that provides an optimized implementation of ReadDir.
    14  type ReadDirFS interface {
    15  	FS
    16  
    17  	// ReadDir reads the named directory
    18  	// and returns a list of directory entries sorted by filename.
    19  	ReadDir(name string) ([]DirEntry, error)
    20  }
    21  
    22  // ReadDir reads the named directory
    23  // and returns a list of directory entries sorted by filename.
    24  //
    25  // If fs implements ReadDirFS, ReadDir calls fs.ReadDir.
    26  // Otherwise ReadDir calls fs.Open and uses ReadDir and Close
    27  // on the returned file.
    28  func ReadDir(fsys FS, name string) ([]DirEntry, error) {
    29  	if fsys, ok := fsys.(ReadDirFS); ok {
    30  		return fsys.ReadDir(name)
    31  	}
    32  
    33  	file, err := fsys.Open(name)
    34  	if err != nil {
    35  		return nil, err
    36  	}
    37  	defer file.Close()
    38  
    39  	dir, ok := file.(ReadDirFile)
    40  	if !ok {
    41  		return nil, &PathError{Op: "readdir", Path: name, Err: errors.New("not implemented")}
    42  	}
    43  
    44  	list, err := dir.ReadDir(-1)
    45  	sort.Slice(list, func(i, j int) bool { return list[i].Name() < list[j].Name() })
    46  	return list, err
    47  }
    48  

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