minio/fs-dir-nix.go

106 lines
2.5 KiB
Go

// +build linux darwin dragonfly freebsd netbsd openbsd
/*
* Minio Cloud Storage, (C) 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package main
import (
"os"
"runtime"
"sort"
"strings"
"syscall"
"unsafe"
)
const (
// Large enough buffer size for ReadDirent() syscall
readDirentBufSize = 4096 * 25
)
// actual length of the byte array from the c - world.
func clen(n []byte) int {
for i := 0; i < len(n); i++ {
if n[i] == 0 {
return i
}
}
return len(n)
}
// parseDirents - inspired from
// https://golang.org/src/syscall/syscall_<os>.go
func parseDirents(buf []byte) []fsDirent {
bufidx := 0
dirents := []fsDirent{}
for bufidx < len(buf) {
dirent := (*syscall.Dirent)(unsafe.Pointer(&buf[bufidx]))
// On non-Linux operating systems for rec length of zero means
// we have reached EOF break out.
if runtime.GOOS != "linux" && dirent.Reclen == 0 {
break
}
bufidx += int(dirent.Reclen)
// Skip dirents if they are absent in directory.
if isEmptyDirent(dirent) {
continue
}
bytes := (*[10000]byte)(unsafe.Pointer(&dirent.Name[0]))
var name = string(bytes[0:clen(bytes[:])])
// Reserved names skip them.
if name == "." || name == ".." {
continue
}
dirents = append(dirents, fsDirent{
name: name,
isDir: (dirent.Type == syscall.DT_DIR),
})
}
return dirents
}
// Read all directory entries, returns a list of lexically sorted entries.
func readDirAll(readDirPath, entryPrefixMatch string) ([]fsDirent, error) {
buf := make([]byte, readDirentBufSize)
f, err := os.Open(readDirPath)
if err != nil {
return nil, err
}
defer f.Close()
dirents := []fsDirent{}
for {
nbuf, err := syscall.ReadDirent(int(f.Fd()), buf)
if err != nil {
return nil, err
}
if nbuf <= 0 {
break
}
for _, dirent := range parseDirents(buf[:nbuf]) {
if dirent.isDir {
dirent.name += string(os.PathSeparator)
dirent.size = 0
}
if strings.HasPrefix(dirent.name, entryPrefixMatch) {
dirents = append(dirents, dirent)
}
}
}
sort.Sort(byDirentNames(dirents))
return dirents, nil
}