readlink.go

     1  // Copyright 2023 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  // ReadLinkFS is the interface implemented by a file system
     8  // that supports reading symbolic links.
     9  type ReadLinkFS interface {
    10  	FS
    11  
    12  	// ReadLink returns the destination of the named symbolic link.
    13  	// If there is an error, it should be of type [*PathError].
    14  	ReadLink(name string) (string, error)
    15  
    16  	// Lstat returns a [FileInfo] describing the named file.
    17  	// If the file is a symbolic link, the returned [FileInfo] describes the symbolic link.
    18  	// Lstat makes no attempt to follow the link.
    19  	// If there is an error, it should be of type [*PathError].
    20  	Lstat(name string) (FileInfo, error)
    21  }
    22  
    23  // ReadLink returns the destination of the named symbolic link.
    24  //
    25  // If fsys does not implement [ReadLinkFS], then ReadLink returns an error.
    26  func ReadLink(fsys FS, name string) (string, error) {
    27  	sym, ok := fsys.(ReadLinkFS)
    28  	if !ok {
    29  		return "", &PathError{Op: "readlink", Path: name, Err: ErrInvalid}
    30  	}
    31  	return sym.ReadLink(name)
    32  }
    33  
    34  // Lstat returns a [FileInfo] describing the named file.
    35  // If the file is a symbolic link, the returned [FileInfo] describes the symbolic link.
    36  // Lstat makes no attempt to follow the link.
    37  //
    38  // If fsys does not implement [ReadLinkFS], then Lstat is identical to [Stat].
    39  func Lstat(fsys FS, name string) (FileInfo, error) {
    40  	sym, ok := fsys.(ReadLinkFS)
    41  	if !ok {
    42  		return Stat(fsys, name)
    43  	}
    44  	return sym.Lstat(name)
    45  }
    46
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