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// Copyright 2016 the Go-FUSE 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 fuse
// all of the code for DirEntryList.
import (
"fmt"
"unsafe"
)
var eightPadding [8]byte
const direntSize = int(unsafe.Sizeof(_Dirent{}))
// DirEntry is a type for PathFileSystem and NodeFileSystem to return
// directory contents in.
type DirEntry struct {
// Mode is the file's mode. Only the high bits (eg. S_IFDIR)
// are considered.
Mode uint32
// Name is the basename of the file in the directory.
Name string
}
func (d DirEntry) String() string {
return fmt.Sprintf("%o: %q", d.Mode, d.Name)
}
// DirEntryList holds the return value for READDIR and READDIRPLUS
// opcodes.
type DirEntryList struct {
buf []byte
size int
offset uint64
}
// NewDirEntryList creates a DirEntryList with the given data buffer
// and offset.
func NewDirEntryList(data []byte, off uint64) *DirEntryList {
return &DirEntryList{
buf: data[:0],
size: len(data),
offset: off,
}
}
// AddDirEntry tries to add an entry, and reports whether it
// succeeded.
func (l *DirEntryList) AddDirEntry(e DirEntry) (bool, uint64) {
return l.Add(0, e.Name, uint64(FUSE_UNKNOWN_INO), e.Mode)
}
// Add adds a direntry to the DirEntryList, returning whether it
// succeeded.
func (l *DirEntryList) Add(prefix int, name string, inode uint64, mode uint32) (bool, uint64) {
padding := (8 - len(name)&7) & 7
delta := padding + direntSize + len(name) + prefix
oldLen := len(l.buf)
newLen := delta + oldLen
if newLen > l.size {
return false, l.offset
}
l.buf = l.buf[:newLen]
oldLen += prefix
dirent := (*_Dirent)(unsafe.Pointer(&l.buf[oldLen]))
dirent.Off = l.offset + 1
dirent.Ino = inode
dirent.NameLen = uint32(len(name))
dirent.Typ = (mode & 0170000) >> 12
oldLen += direntSize
copy(l.buf[oldLen:], name)
oldLen += len(name)
if padding > 0 {
copy(l.buf[oldLen:], eightPadding[:padding])
}
l.offset = dirent.Off
return true, l.offset
}
// AddDirLookupEntry is used for ReadDirPlus. It serializes a DirEntry
// and returns the space for entry. If no space is left, returns a nil
// pointer.
func (l *DirEntryList) AddDirLookupEntry(e DirEntry) (*EntryOut, uint64) {
lastStart := len(l.buf)
ok, off := l.Add(int(unsafe.Sizeof(EntryOut{})), e.Name,
uint64(FUSE_UNKNOWN_INO), e.Mode)
if !ok {
return nil, off
}
return (*EntryOut)(unsafe.Pointer(&l.buf[lastStart])), off
}
func (l *DirEntryList) bytes() []byte {
return l.buf
}
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