github.com/freddyisaac/sicortex-golang@v0.0.0-20231019035217-e03519e66f60/src/os/dir_unix.go (about)

     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 dragonfly freebsd linux nacl netbsd openbsd solaris
     6  
     7  package os
     8  
     9  import (
    10  	"io"
    11  	"syscall"
    12  )
    13  
    14  const (
    15  	blockSize = 4096
    16  )
    17  
    18  func (f *File) readdir(n int) (fi []FileInfo, err error) {
    19  	dirname := f.name
    20  	if dirname == "" {
    21  		dirname = "."
    22  	}
    23  	names, err := f.Readdirnames(n)
    24  	fi = make([]FileInfo, 0, len(names))
    25  	for _, filename := range names {
    26  		fip, lerr := lstat(dirname + "/" + filename)
    27  		if IsNotExist(lerr) {
    28  			// File disappeared between readdir + stat.
    29  			// Just treat it as if it didn't exist.
    30  			continue
    31  		}
    32  		if lerr != nil {
    33  			return fi, lerr
    34  		}
    35  		fi = append(fi, fip)
    36  	}
    37  	if len(fi) == 0 && err == nil && n > 0 {
    38  		// Per File.Readdir, the slice must be non-empty or err
    39  		// must be non-nil if n > 0.
    40  		err = io.EOF
    41  	}
    42  	return fi, err
    43  }
    44  
    45  func (f *File) readdirnames(n int) (names []string, err error) {
    46  	// If this file has no dirinfo, create one.
    47  	if f.dirinfo == nil {
    48  		f.dirinfo = new(dirInfo)
    49  		// The buffer must be at least a block long.
    50  		f.dirinfo.buf = make([]byte, blockSize)
    51  	}
    52  	d := f.dirinfo
    53  
    54  	size := n
    55  	if size <= 0 {
    56  		size = 100
    57  		n = -1
    58  	}
    59  
    60  	names = make([]string, 0, size) // Empty with room to grow.
    61  	for n != 0 {
    62  		// Refill the buffer if necessary
    63  		if d.bufp >= d.nbuf {
    64  			d.bufp = 0
    65  			var errno error
    66  			d.nbuf, errno = fixCount(syscall.ReadDirent(f.fd, d.buf))
    67  			if errno != nil {
    68  				return names, NewSyscallError("readdirent", errno)
    69  			}
    70  			if d.nbuf <= 0 {
    71  				break // EOF
    72  			}
    73  		}
    74  
    75  		// Drain the buffer
    76  		var nb, nc int
    77  		nb, nc, names = syscall.ParseDirent(d.buf[d.bufp:d.nbuf], n, names)
    78  		d.bufp += nb
    79  		n -= nc
    80  	}
    81  	if n >= 0 && len(names) == 0 {
    82  		return names, io.EOF
    83  	}
    84  	return names, nil
    85  }