stat.go

/*
Constants/functions for interpreting results of os.Stat() and os.Lstat().

Suggested usage: import github.com/goimp/stat
*/
package stat

// Indices for stat struct members in the tuple returned by os.Stat()
const (
	ST_MODE  = 0
	ST_INO   = 1
	ST_DEV   = 2
	ST_NLINK = 3
	ST_UID   = 4
	ST_GID   = 5
	ST_SIZE  = 6
	ST_ATIME = 7
	ST_MTIME = 8
	ST_CTIME = 9
)

// Extract bits from the mode

// Return the portion of the file's mode that can be set by os.chmod().
func S_IMODE(mode uint32) uint32 {
	return mode & 0o7777
}

// Return the portion of the file's mode that describes the file type.
func S_IFMT(mode uint32) uint32 {
	return mode & 0o170000
}

// Constants used as S_IFMT() for various file types
// (not all are implemented on all systems)
const (
	S_IFDIR  = 0o040000 // directory
	S_IFCHR  = 0o020000 // character device
	S_IFBLK  = 0o060000 // block device
	S_IFREG  = 0o100000 // regular file
	S_IFIFO  = 0o010000 // fifo (named pipe)
	S_IFLNK  = 0o120000 // symbolic link
	S_IFSOCK = 0o140000 // socket file
	// Fallbacks for uncommon platform-specific constants
	S_IFDOOR = 0
	S_IFPORT = 0
	S_IFWHT  = 0
)

// Functions to test for each file type

// Return True if mode is from a directory.
func S_ISDIR(mode uint32) bool {
	return S_IFMT(mode) == S_IFDIR
}

// Return True if mode is from a character special device file.
func S_ISCHR(mode uint32) bool {
	return S_IFMT(mode) == S_IFCHR
}

// Return True if mode is from a block special device file.
func S_ISBLK(mode uint32) bool {
	return S_IFMT(mode) == S_IFBLK
}

// Return True if mode is from a regular file.
func S_ISREG(mode uint32) bool {
	return S_IFMT(mode) == S_IFREG
}

// Return True if mode is from a FIFO (named pipe).
func S_ISFIFO(mode uint32) bool {
	return S_IFMT(mode) == S_IFIFO
}

// Return True if mode is from a symbolic link.
func S_ISLNK(mode uint32) bool {
	return S_IFMT(mode) == S_IFLNK
}

// Return True if mode is from a socket.
func S_ISSOCK(mode uint32) bool {
	return S_IFMT(mode) == S_IFSOCK
}

// Return True if mode is from a door.
func S_ISDOOR(mode uint32) bool {
	return false
}

// Return True if mode is from an event port.
func S_ISPORT(mode uint32) bool {
	return false
}

// Return True if mode is from a whiteout.
func S_ISWHT(mode uint32) bool {
	return false
}

// Names for permission bits
const (
	S_ISUID  = 0o4000  // set UID bit
	S_ISGID  = 0o2000  // set GID bit
	S_ENFMT  = S_ISGID // file locking enforcement
	S_ISVTX  = 0o1000  // sticky bit
	S_IREAD  = 0o0400  // Unix V7 synonym for S_IRUSR
	S_IWRITE = 0o0200  // Unix V7 synonym for S_IWUSR
	S_IEXEC  = 0o0100  // Unix V7 synonym for S_IXUSR
	S_IRWXU  = 0o0700  // mask for owner permissions
	S_IRUSR  = 0o0400  // read by owner
	S_IWUSR  = 0o0200  // write by owner
	S_IXUSR  = 0o0100  // execute by owner
	S_IRWXG  = 0o0070  // mask for group permissions
	S_IRGRP  = 0o0040  // read by group
	S_IWGRP  = 0o0020  // write by group
	S_IXGRP  = 0o0010  // execute by group
	S_IRWXO  = 0o0007  // mask for others (not in group) permissions
	S_IROTH  = 0o0004  // read by others
	S_IWOTH  = 0o0002  // write by others
	S_IXOTH  = 0o0001  // execute by others
)

// Names for file flags
const (
	UF_SETTABLE   = 0x0000ffff // owner settable flags
	UF_NODUMP     = 0x00000001 // do not dump file
	UF_IMMUTABLE  = 0x00000002 // file may not be changed
	UF_APPEND     = 0x00000004 // file may only be appended to
	UF_OPAQUE     = 0x00000008 // directory is opaque when viewed through a union stack
	UF_NOUNLINK   = 0x00000010 // file may not be renamed or deleted
	UF_COMPRESSED = 0x00000020 // macOS: file is compressed
	UF_TRACKED    = 0x00000040 // macOS: used for handling document IDs
	UF_DATAVAULT  = 0x00000080 // macOS: entitlement needed for I/O
	UF_HIDDEN     = 0x00008000 // macOS: file should not be displayed
	SF_SETTABLE   = 0xffff0000 // superuser settable flags
	SF_ARCHIVED   = 0x00010000 // file may be archived
	SF_IMMUTABLE  = 0x00020000 // file may not be changed
	SF_APPEND     = 0x00040000 // file may only be appended to
	SF_RESTRICTED = 0x00080000 // macOS: entitlement needed for writing
	SF_NOUNLINK   = 0x00100000 // file may not be renamed or deleted
	SF_SNAPSHOT   = 0x00200000 // file is a snapshot file
	SF_FIRMLINK   = 0x00800000 // macOS: file is a firmlink
	SF_DATALESS   = 0x40000000 // macOS: file is a dataless object
)

// File type chars according to:
// http://en.wikibooks.org/wiki/C_Programming/POSIX_Reference/sys/stat.h
var fileModeTable = [][]struct {
	Mask   uint32
	Symbol string
}{
	{
		{S_IFLNK, "l"},
		{S_IFSOCK, "s"},
		{S_IFREG, "-"},
		{S_IFBLK, "b"},
		{S_IFDIR, "d"},
		{S_IFCHR, "c"},
		{S_IFIFO, "p"},
	},
	{{S_IRUSR, "r"}},
	{{S_IWUSR, "w"}},
	{
		{S_IXUSR | S_ISUID, "s"},
		{S_ISUID, "S"},
		{S_IXUSR, "x"},
	},
	{{S_IRGRP, "r"}},
	{{S_IWGRP, "w"}},
	{
		{S_IXGRP | S_ISGID, "s"},
		{S_ISGID, "S"},
		{S_IXGRP, "x"},
	},
	{{S_IROTH, "r"}},
	{{S_IWOTH, "w"}},
	{
		{S_IXOTH | S_ISVTX, "t"},
		{S_ISVTX, "T"},
		{S_IXOTH, "x"},
	},
}

// Convert a file's mode to a string of the form '-rwxrwxrwx'.
func FileMode(mode uint32) string {
	var perm []rune

	for index, table := range fileModeTable {
		found := false
		for _, entry := range table {
			if mode&entry.Mask == entry.Mask {
				perm = append(perm, rune(entry.Symbol[0]))
				found = true
				break
			}
		}
		if !found {
			if index == 0 {
				// Unknown file type
				perm = append(perm, '?')
			} else {
				perm = append(perm, '-')
			}
		}
	}

	return string(perm)
}

// Windows FILE_ATTRIBUTE constants for interpreting os.Stat()'s
// "st_file_attributes" member

const (
	FILE_ATTRIBUTE_ARCHIVE             = 32
	FILE_ATTRIBUTE_COMPRESSED          = 2048
	FILE_ATTRIBUTE_DEVICE              = 64
	FILE_ATTRIBUTE_DIRECTORY           = 16
	FILE_ATTRIBUTE_ENCRYPTED           = 16384
	FILE_ATTRIBUTE_HIDDEN              = 2
	FILE_ATTRIBUTE_INTEGRITY_STREAM    = 32768
	FILE_ATTRIBUTE_NORMAL              = 128
	FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 8192
	FILE_ATTRIBUTE_NO_SCRUB_DATA       = 131072
	FILE_ATTRIBUTE_OFFLINE             = 4096
	FILE_ATTRIBUTE_READONLY            = 1
	FILE_ATTRIBUTE_REPARSE_POINT       = 1024
	FILE_ATTRIBUTE_SPARSE_FILE         = 512
	FILE_ATTRIBUTE_SYSTEM              = 4
	FILE_ATTRIBUTE_TEMPORARY           = 256
	FILE_ATTRIBUTE_VIRTUAL             = 65536
)