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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfsitem
import (
"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
)
// Metadata items map from regions in the logical address space to
// regions in a file.
//
// Metadata is like Extent, but doesn't have .Info.
//
// Compare with:
//
// - Extents, which are the same as Metadata, but have an extra
// .Info member.
// - FileExtents, which map from regions in a file to regions in the
// logical address space.
//
// Key:
//
// key.objectid = laddr of the extent
// key.offset = length of the extent
type Metadata struct { // complex METADATA_ITEM=169
Head ExtentHeader
Refs []ExtentInlineRef
}
func (o *Metadata) Free() {
for i := range o.Refs {
if o.Refs[i].Body != nil {
o.Refs[i].Body.Free()
}
o.Refs[i] = ExtentInlineRef{}
}
extentInlineRefPool.Put(o.Refs)
*o = Metadata{}
metadataPool.Put(o)
}
func (o Metadata) Clone() Metadata {
ret := o
ret.Refs = extentInlineRefPool.Get(len(o.Refs))
copy(ret.Refs, o.Refs)
for i := range ret.Refs {
ret.Refs[i].Body = o.Refs[i].Body.CloneItem()
}
return ret
}
func (o *Metadata) UnmarshalBinary(dat []byte) (int, error) {
*o = Metadata{}
n, err := binstruct.Unmarshal(dat, &o.Head)
if err != nil {
return n, err
}
if n < len(dat) {
o.Refs = extentInlineRefPool.Get(1)[:0]
}
for n < len(dat) {
var ref ExtentInlineRef
_n, err := binstruct.Unmarshal(dat[n:], &ref)
n += _n
o.Refs = append(o.Refs, ref)
if err != nil {
return n, err
}
}
return n, nil
}
func (o Metadata) MarshalBinary() ([]byte, error) {
dat, err := binstruct.Marshal(o.Head)
if err != nil {
return dat, err
}
for _, ref := range o.Refs {
bs, err := binstruct.Marshal(ref)
dat = append(dat, bs...)
if err != nil {
return dat, err
}
}
return dat, nil
}
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