| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package os |
| |
| import ( |
| "syscall" |
| "unsafe" |
| ) |
| |
| const ( |
| blockSize = 4096 // TODO(r): use statfs |
| ) |
| |
| // Readdirnames reads the contents of the directory associated with file and |
| // returns an array of up to count names, in directory order. Subsequent |
| // calls on the same file will yield further names. |
| // A negative count means to read until EOF. |
| // Readdirnames returns the array and an Error, if any. |
| func (file *File) Readdirnames(count int) (names []string, err Error) { |
| // If this file has no dirinfo, create one. |
| if file.dirinfo == nil { |
| file.dirinfo = new(dirInfo) |
| // The buffer must be at least a block long. |
| // TODO(r): use fstatfs to find fs block size. |
| file.dirinfo.buf = make([]byte, blockSize) |
| } |
| d := file.dirinfo |
| size := count |
| if size < 0 { |
| size = 100 |
| } |
| names = make([]string, 0, size) // Empty with room to grow. |
| for count != 0 { |
| // Refill the buffer if necessary |
| if d.bufp >= d.nbuf { |
| var errno int |
| d.bufp = 0 |
| // Final argument is (basep *uintptr) and the syscall doesn't take nil. |
| d.nbuf, errno = syscall.Getdirentries(file.fd, d.buf, new(uintptr)) |
| if errno != 0 { |
| d.nbuf = 0 |
| return names, NewSyscallError("getdirentries", errno) |
| } |
| if d.nbuf <= 0 { |
| break // EOF |
| } |
| } |
| // Drain the buffer |
| for count != 0 && d.bufp < d.nbuf { |
| dirent := (*syscall.Dirent)(unsafe.Pointer(&d.buf[d.bufp])) |
| if dirent.Reclen == 0 { |
| d.bufp = d.nbuf |
| break |
| } |
| d.bufp += int(dirent.Reclen) |
| if dirent.Ino == 0 { // File absent in directory. |
| continue |
| } |
| bytes := (*[10000]byte)(unsafe.Pointer(&dirent.Name[0])) |
| var name = string(bytes[0:dirent.Namlen]) |
| if name == "." || name == ".." { // Useless names |
| continue |
| } |
| count-- |
| names = append(names, name) |
| } |
| } |
| return names, nil |
| } |