go-ceph/cephfs/directory.go

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package cephfs
/*
#cgo LDFLAGS: -lcephfs
#cgo CPPFLAGS: -D_FILE_OFFSET_BITS=64
#include <stdlib.h>
#include <dirent.h>
#include <cephfs/libcephfs.h>
*/
import "C"
import (
"unsafe"
)
// Directory represents an open directory handle.
type Directory struct {
mount *MountInfo
dir *C.struct_ceph_dir_result
}
// OpenDir returns a new Directory handle open for I/O.
//
// Implements:
// int ceph_opendir(struct ceph_mount_info *cmount, const char *name, struct ceph_dir_result **dirpp);
func (mount *MountInfo) OpenDir(path string) (*Directory, error) {
var dir *C.struct_ceph_dir_result
cPath := C.CString(path)
defer C.free(unsafe.Pointer(cPath))
ret := C.ceph_opendir(mount.mount, cPath, &dir)
if ret != 0 {
return nil, getError(ret)
}
return &Directory{
mount: mount,
dir: dir,
}, nil
}
// Close the open directory handle.
//
// Implements:
// int ceph_closedir(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp);
func (dir *Directory) Close() error {
return getError(C.ceph_closedir(dir.mount.mount, dir.dir))
}
// Inode represents an inode number in the file system.
type Inode uint64
// DType values are used to determine, when possible, the file type
// of a directory entry.
type DType uint8
const (
// DTypeBlk indicates a directory entry is a block device.
DTypeBlk = DType(C.DT_BLK)
// DTypeChr indicates a directory entry is a character device.
DTypeChr = DType(C.DT_CHR)
// DTypeDir indicates a directory entry is a directory.
DTypeDir = DType(C.DT_DIR)
// DTypeFIFO indicates a directory entry is a named pipe (FIFO).
DTypeFIFO = DType(C.DT_FIFO)
// DTypeLnk indicates a directory entry is a symbolic link.
DTypeLnk = DType(C.DT_LNK)
// DTypeReg indicates a directory entry is a regular file.
DTypeReg = DType(C.DT_REG)
// DTypeSock indicates a directory entry is a UNIX domain socket.
DTypeSock = DType(C.DT_SOCK)
// DTypeUnknown indicates that the file type could not be determined.
DTypeUnknown = DType(C.DT_UNKNOWN)
)
// DirEntry represents an entry within a directory.
type DirEntry struct {
inode Inode
name string
dtype DType
}
// Name returns the directory entry's name.
func (d *DirEntry) Name() string {
return d.name
}
// Inode returns the directory entry's inode number.
func (d *DirEntry) Inode() Inode {
return d.inode
}
// DType returns the Directory-entry's Type, indicating if it
// is a regular file, directory, etc.
// DType may be unknown and thus require an additional call
// (stat for example) if Unknown.
func (d *DirEntry) DType() DType {
return d.dtype
}
// toDirEntry converts a c struct dirent to our go wrapper.
func toDirEntry(de *C.struct_dirent) *DirEntry {
return &DirEntry{
inode: Inode(de.d_ino),
name: C.GoString(&de.d_name[0]),
dtype: DType(de.d_type),
}
}
// ReadDir reads a single directory entry from the open Directory.
// A nil DirEntry pointer will be returned when the Directory stream has been
// exhausted.
//
// Implements:
// int ceph_readdir_r(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp, struct dirent *de);
func (dir *Directory) ReadDir() (*DirEntry, error) {
var de C.struct_dirent
ret := C.ceph_readdir_r(dir.mount.mount, dir.dir, &de)
if ret < 0 {
return nil, getError(ret)
}
if ret == 0 {
return nil, nil // End-of-stream
}
return toDirEntry(&de), nil
}
// RewindDir sets the directory stream to the beginning of the directory.
//
// Implements:
// void ceph_rewinddir(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp);
func (dir *Directory) RewindDir() {
C.ceph_rewinddir(dir.mount.mount, dir.dir)
}
// dirEntries provides a convenient wrapper around slices of DirEntry items.
// For example, use the Names() call to easily get only the names from a
// DirEntry slice.
type dirEntries []*DirEntry
// list returns all the contents of a directory as a dirEntries slice.
//
// list is implemented using ReadDir. If any of the calls to ReadDir returns
// an error List will return an error. However, all previous entries
// collected will still be returned. Callers of this function may want to check
// the entries return value even when an error is returned.
// List rewinds the handle every time it is called to get a full
// listing of directory contents.
func (dir *Directory) list() (dirEntries, error) {
var (
err error
entry *DirEntry
entries = make(dirEntries, 0)
)
dir.RewindDir()
for {
entry, err = dir.ReadDir()
if err != nil || entry == nil {
break
}
entries = append(entries, entry)
}
return entries, err
}
// names returns a slice of only the name fields from dir entries.
func (entries dirEntries) names() []string {
names := make([]string, len(entries))
for i, v := range entries {
names[i] = v.Name()
}
return names
}