Source file src/pkg/os/dir_unix.go

     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	// +build darwin freebsd linux netbsd openbsd
     6	
     7	package os
     8	
     9	import (
    10		"io"
    11		"syscall"
    12	)
    13	
    14	const (
    15		blockSize = 4096
    16	)
    17	
    18	func (f *File) readdirnames(n int) (names []string, err error) {
    19		// If this file has no dirinfo, create one.
    20		if f.dirinfo == nil {
    21			f.dirinfo = new(dirInfo)
    22			// The buffer must be at least a block long.
    23			f.dirinfo.buf = make([]byte, blockSize)
    24		}
    25		d := f.dirinfo
    26	
    27		size := n
    28		if size <= 0 {
    29			size = 100
    30			n = -1
    31		}
    32	
    33		names = make([]string, 0, size) // Empty with room to grow.
    34		for n != 0 {
    35			// Refill the buffer if necessary
    36			if d.bufp >= d.nbuf {
    37				d.bufp = 0
    38				var errno error
    39				d.nbuf, errno = syscall.ReadDirent(f.fd, d.buf)
    40				if errno != nil {
    41					return names, NewSyscallError("readdirent", errno)
    42				}
    43				if d.nbuf <= 0 {
    44					break // EOF
    45				}
    46			}
    47	
    48			// Drain the buffer
    49			var nb, nc int
    50			nb, nc, names = syscall.ParseDirent(d.buf[d.bufp:d.nbuf], n, names)
    51			d.bufp += nb
    52			n -= nc
    53		}
    54		if n >= 0 && len(names) == 0 {
    55			return names, io.EOF
    56		}
    57		return names, nil
    58	}