github.com/powerman/golang-tools@v0.1.11-0.20220410185822-5ad214d8d803/godoc/vfs/fs.go (about)

     1  // Copyright 2021 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  //go:build go1.16
     6  // +build go1.16
     7  
     8  package vfs
     9  
    10  import (
    11  	"io/fs"
    12  	"os"
    13  	"path"
    14  	"strings"
    15  )
    16  
    17  // FromFS converts an fs.FS to the FileSystem interface.
    18  func FromFS(fsys fs.FS) FileSystem {
    19  	return &fsysToFileSystem{fsys}
    20  }
    21  
    22  type fsysToFileSystem struct {
    23  	fsys fs.FS
    24  }
    25  
    26  func (f *fsysToFileSystem) fsPath(name string) string {
    27  	name = path.Clean(name)
    28  	if name == "/" {
    29  		return "."
    30  	}
    31  	return strings.TrimPrefix(name, "/")
    32  }
    33  
    34  func (f *fsysToFileSystem) Open(name string) (ReadSeekCloser, error) {
    35  	file, err := f.fsys.Open(f.fsPath(name))
    36  	if err != nil {
    37  		return nil, err
    38  	}
    39  	if rsc, ok := file.(ReadSeekCloser); ok {
    40  		return rsc, nil
    41  	}
    42  	return &noSeekFile{f.fsPath(name), file}, nil
    43  }
    44  
    45  func (f *fsysToFileSystem) Lstat(name string) (os.FileInfo, error) {
    46  	return fs.Stat(f.fsys, f.fsPath(name))
    47  }
    48  
    49  func (f *fsysToFileSystem) Stat(name string) (os.FileInfo, error) {
    50  	return fs.Stat(f.fsys, f.fsPath(name))
    51  }
    52  
    53  func (f *fsysToFileSystem) RootType(name string) RootType { return "" }
    54  
    55  func (f *fsysToFileSystem) ReadDir(name string) ([]os.FileInfo, error) {
    56  	dirs, err := fs.ReadDir(f.fsys, f.fsPath(name))
    57  	var infos []os.FileInfo
    58  	for _, d := range dirs {
    59  		info, err1 := d.Info()
    60  		if err1 != nil {
    61  			if err == nil {
    62  				err = err1
    63  			}
    64  			continue
    65  		}
    66  		infos = append(infos, info)
    67  	}
    68  	return infos, err
    69  }
    70  
    71  func (f *fsysToFileSystem) String() string { return "io/fs" }
    72  
    73  type noSeekFile struct {
    74  	path string
    75  	fs.File
    76  }
    77  
    78  func (f *noSeekFile) Seek(offset int64, whence int) (int64, error) {
    79  	return 0, &fs.PathError{Op: "seek", Path: f.path, Err: fs.ErrInvalid}
    80  }