1 // Copyright 2009 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 ioutil implements some I/O utility functions. 6 // 7 // Deprecated: As of Go 1.16, the same functionality is now provided 8 // by package [io] or package [os], and those implementations 9 // should be preferred in new code. 10 // See the specific function documentation for details. 11 package ioutil 12 13 import ( 14 "io" 15 "io/fs" 16 "os" 17 "slices" 18 "strings" 19 ) 20 21 // ReadAll reads from r until an error or EOF and returns the data it read. 22 // A successful call returns err == nil, not err == EOF. Because ReadAll is 23 // defined to read from src until EOF, it does not treat an EOF from Read 24 // as an error to be reported. 25 // 26 // Deprecated: As of Go 1.16, this function simply calls [io.ReadAll]. 27 func ReadAll(r io.Reader) ([]byte, error) { 28 return io.ReadAll(r) 29 } 30 31 // ReadFile reads the file named by filename and returns the contents. 32 // A successful call returns err == nil, not err == EOF. Because ReadFile 33 // reads the whole file, it does not treat an EOF from Read as an error 34 // to be reported. 35 // 36 // Deprecated: As of Go 1.16, this function simply calls [os.ReadFile]. 37 func ReadFile(filename string) ([]byte, error) { 38 return os.ReadFile(filename) 39 } 40 41 // WriteFile writes data to a file named by filename. 42 // If the file does not exist, WriteFile creates it with permissions perm 43 // (before umask); otherwise WriteFile truncates it before writing, without changing permissions. 44 // 45 // Deprecated: As of Go 1.16, this function simply calls [os.WriteFile]. 46 func WriteFile(filename string, data []byte, perm fs.FileMode) error { 47 return os.WriteFile(filename, data, perm) 48 } 49 50 // ReadDir reads the directory named by dirname and returns 51 // a list of fs.FileInfo for the directory's contents, 52 // sorted by filename. If an error occurs reading the directory, 53 // ReadDir returns no directory entries along with the error. 54 // 55 // Deprecated: As of Go 1.16, [os.ReadDir] is a more efficient and correct choice: 56 // it returns a list of [fs.DirEntry] instead of [fs.FileInfo], 57 // and it returns partial results in the case of an error 58 // midway through reading a directory. 59 // 60 // If you must continue obtaining a list of [fs.FileInfo], you still can: 61 // 62 // entries, err := os.ReadDir(dirname) 63 // if err != nil { ... } 64 // infos := make([]fs.FileInfo, 0, len(entries)) 65 // for _, entry := range entries { 66 // info, err := entry.Info() 67 // if err != nil { ... } 68 // infos = append(infos, info) 69 // } 70 func ReadDir(dirname string) ([]fs.FileInfo, error) { 71 f, err := os.Open(dirname) 72 if err != nil { 73 return nil, err 74 } 75 list, err := f.Readdir(-1) 76 f.Close() 77 if err != nil { 78 return nil, err 79 } 80 slices.SortFunc(list, func(a, b os.FileInfo) int { 81 return strings.Compare(a.Name(), b.Name()) 82 }) 83 return list, nil 84 } 85 86 // NopCloser returns a ReadCloser with a no-op Close method wrapping 87 // the provided Reader r. 88 // 89 // Deprecated: As of Go 1.16, this function simply calls [io.NopCloser]. 90 func NopCloser(r io.Reader) io.ReadCloser { 91 return io.NopCloser(r) 92 } 93 94 // Discard is an io.Writer on which all Write calls succeed 95 // without doing anything. 96 // 97 // Deprecated: As of Go 1.16, this value is simply [io.Discard]. 98 var Discard io.Writer = io.Discard 99