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 os 6 7 import ( 8 "syscall" 9 "time" 10 ) 11 12 // Getpagesize returns the underlying system's memory page size. 13 func Getpagesize() int { return syscall.Getpagesize() } 14 15 // File represents an open file descriptor. 16 type File struct { 17 *file // os specific 18 } 19 20 // A FileInfo describes a file and is returned by Stat and Lstat. 21 type FileInfo interface { 22 Name() string // base name of the file 23 Size() int64 // length in bytes for regular files; system-dependent for others 24 Mode() FileMode // file mode bits 25 ModTime() time.Time // modification time 26 IsDir() bool // abbreviation for Mode().IsDir() 27 Sys() interface{} // underlying data source (can return nil) 28 } 29 30 // A FileMode represents a file's mode and permission bits. 31 // The bits have the same definition on all systems, so that 32 // information about files can be moved from one system 33 // to another portably. Not all bits apply to all systems. 34 // The only required bit is ModeDir for directories. 35 type FileMode uint32 36 37 // The defined file mode bits are the most significant bits of the FileMode. 38 // The nine least-significant bits are the standard Unix rwxrwxrwx permissions. 39 // The values of these bits should be considered part of the public API and 40 // may be used in wire protocols or disk representations: they must not be 41 // changed, although new bits might be added. 42 const ( 43 // The single letters are the abbreviations 44 // used by the String method's formatting. 45 ModeDir FileMode = 1 << (32 - 1 - iota) // d: is a directory 46 ModeAppend // a: append-only 47 ModeExclusive // l: exclusive use 48 ModeTemporary // T: temporary file; Plan 9 only 49 ModeSymlink // L: symbolic link 50 ModeDevice // D: device file 51 ModeNamedPipe // p: named pipe (FIFO) 52 ModeSocket // S: Unix domain socket 53 ModeSetuid // u: setuid 54 ModeSetgid // g: setgid 55 ModeCharDevice // c: Unix character device, when ModeDevice is set 56 ModeSticky // t: sticky 57 58 // Mask for the type bits. For regular files, none will be set. 59 ModeType = ModeDir | ModeSymlink | ModeNamedPipe | ModeSocket | ModeDevice 60 61 ModePerm FileMode = 0777 // Unix permission bits 62 ) 63 64 func (m FileMode) String() string { 65 const str = "dalTLDpSugct" 66 var buf [32]byte // Mode is uint32. 67 w := 0 68 for i, c := range str { 69 if m&(1<<uint(32-1-i)) != 0 { 70 buf[w] = byte(c) 71 w++ 72 } 73 } 74 if w == 0 { 75 buf[w] = '-' 76 w++ 77 } 78 const rwx = "rwxrwxrwx" 79 for i, c := range rwx { 80 if m&(1<<uint(9-1-i)) != 0 { 81 buf[w] = byte(c) 82 } else { 83 buf[w] = '-' 84 } 85 w++ 86 } 87 return string(buf[:w]) 88 } 89 90 // IsDir reports whether m describes a directory. 91 // That is, it tests for the ModeDir bit being set in m. 92 func (m FileMode) IsDir() bool { 93 return m&ModeDir != 0 94 } 95 96 // IsRegular reports whether m describes a regular file. 97 // That is, it tests that no mode type bits are set. 98 func (m FileMode) IsRegular() bool { 99 return m&ModeType == 0 100 } 101 102 // Perm returns the Unix permission bits in m. 103 func (m FileMode) Perm() FileMode { 104 return m & ModePerm 105 } 106 107 func (fs *fileStat) Name() string { return fs.name } 108 func (fs *fileStat) IsDir() bool { return fs.Mode().IsDir() } 109 110 // SameFile reports whether fi1 and fi2 describe the same file. 111 // For example, on Unix this means that the device and inode fields 112 // of the two underlying structures are identical; on other systems 113 // the decision may be based on the path names. 114 // SameFile only applies to results returned by this package's Stat. 115 // It returns false in other cases. 116 func SameFile(fi1, fi2 FileInfo) bool { 117 fs1, ok1 := fi1.(*fileStat) 118 fs2, ok2 := fi2.(*fileStat) 119 if !ok1 || !ok2 { 120 return false 121 } 122 return sameFile(fs1, fs2) 123 } 124
