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package btrfsitem
import (
"fmt"
"lukeshu.com/btrfs-tools/pkg/binstruct"
"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsvol"
"lukeshu.com/btrfs-tools/pkg/btrfs/internal"
)
// key.objectid = inode
// key.offset = offset within file
type FileExtent struct { // EXTENT_DATA=108
Generation internal.Generation `bin:"off=0x0, siz=0x8"` // transaction ID that created this extent
RAMBytes int64 `bin:"off=0x8, siz=0x8"` // upper bound of what compressed data will decompress to
// 32 bits describing the data encoding
Compression CompressionType `bin:"off=0x10, siz=0x1"`
Encryption uint8 `bin:"off=0x11, siz=0x1"`
OtherEncoding uint16 `bin:"off=0x12, siz=0x2"` // reserved for later use
Type FileExtentType `bin:"off=0x14, siz=0x1"` // inline data or real extent
binstruct.End `bin:"off=0x15"`
// only one of these, depending on .Type
BodyInline []byte `bin:"-"`
BodyReg struct {
// Position of extent within the device
DiskByteNr btrfsvol.LogicalAddr `bin:"off=0x0, siz=0x8"`
DiskNumBytes btrfsvol.AddrDelta `bin:"off=0x8, siz=0x8"`
// Position of data within the extent
Offset btrfsvol.AddrDelta `bin:"off=0x10, siz=0x8"`
NumBytes btrfsvol.AddrDelta `bin:"off=0x18, siz=0x8"`
binstruct.End `bin:"off=0x20"`
} `bin:"-"`
BodyPrealloc struct {
// Position of extent within the device
DiskByteNr btrfsvol.LogicalAddr `bin:"off=0x0, siz=0x8"`
DiskNumBytes btrfsvol.AddrDelta `bin:"off=0x8, siz=0x8"`
// Position of data within the extent
Offset btrfsvol.AddrDelta `bin:"off=0x10, siz=0x8"`
NumBytes btrfsvol.AddrDelta `bin:"off=0x18, siz=0x8"`
binstruct.End `bin:"off=0x20"`
} `bin:"-"`
}
func (o *FileExtent) UnmarshalBinary(dat []byte) (int, error) {
n, err := binstruct.UnmarshalWithoutInterface(dat, o)
if err != nil {
return n, err
}
switch o.Type {
case FILE_EXTENT_INLINE:
o.BodyInline = dat[n:]
n += len(o.BodyInline)
case FILE_EXTENT_REG:
_n, err := binstruct.Unmarshal(dat[n:], &o.BodyReg)
n += _n
if err != nil {
return n, err
}
case FILE_EXTENT_PREALLOC:
_n, err := binstruct.Unmarshal(dat[n:], &o.BodyPrealloc)
n += _n
if err != nil {
return n, err
}
default:
return n, fmt.Errorf("unknown file extent type %v", o.Type)
}
return n, nil
}
func (o FileExtent) MarshalBinary() ([]byte, error) {
dat, err := binstruct.MarshalWithoutInterface(o)
if err != nil {
return dat, err
}
switch o.Type {
case FILE_EXTENT_INLINE:
dat = append(dat, o.BodyInline...)
case FILE_EXTENT_REG:
bs, err := binstruct.Marshal(o.BodyReg)
dat = append(dat, bs...)
if err != nil {
return dat, err
}
case FILE_EXTENT_PREALLOC:
bs, err := binstruct.Marshal(o.BodyPrealloc)
dat = append(dat, bs...)
if err != nil {
return dat, err
}
default:
return dat, fmt.Errorf("unknown file extent type %v", o.Type)
}
return dat, nil
}
type FileExtentType uint8
const (
FILE_EXTENT_INLINE = FileExtentType(iota)
FILE_EXTENT_REG
FILE_EXTENT_PREALLOC
)
func (fet FileExtentType) String() string {
names := map[FileExtentType]string{
FILE_EXTENT_INLINE: "inline",
FILE_EXTENT_REG: "regular",
FILE_EXTENT_PREALLOC: "prealloc",
}
name, ok := names[fet]
if !ok {
name = "unknown"
}
return fmt.Sprintf("%d (%s)", fet, name)
}
type CompressionType uint8
const (
COMPRESS_NONE = CompressionType(iota)
COMPRESS_ZLIB
COMPRESS_LZO
COMPRESS_ZSTD
)
func (ct CompressionType) String() string {
names := map[CompressionType]string{
COMPRESS_NONE: "none",
COMPRESS_ZLIB: "zlib",
COMPRESS_LZO: "lzo",
COMPRESS_ZSTD: "zstd",
}
name, ok := names[ct]
if !ok {
name = "unknown"
}
return fmt.Sprintf("%d (%s)", ct, name)
}
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