btrfsitem: Have all Item implementations be pointers to structs

5 files changed, 51 insertions, 47 deletions

diff --git a/lib/btrfs/btrfsitem/item_extent.go b/lib/btrfs/btrfsitem/item_extent.go
index 66aae1d..72371a9 100644
--- a/lib/btrfs/btrfsitem/item_extent.go
+++ b/lib/btrfs/btrfsitem/item_extent.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -114,8 +114,8 @@ func (o *ExtentInlineRef) UnmarshalBinary(dat []byte) (int, error) {
 			return n, err
 		}
 	case EXTENT_DATA_REF_KEY:
-		var dref ExtentDataRef
-		_n, err := binstruct.Unmarshal(dat[n:], &dref)
+		dref := new(ExtentDataRef)
+		_n, err := binstruct.Unmarshal(dat[n:], dref)
 		n += _n
 		o.Body = dref
 		if err != nil {
@@ -127,8 +127,8 @@ func (o *ExtentInlineRef) UnmarshalBinary(dat []byte) (int, error) {
 		if err != nil {
 			return n, err
 		}
-		var sref SharedDataRef
-		_n, err = binstruct.Unmarshal(dat[n:], &sref)
+		sref := new(SharedDataRef)
+		_n, err = binstruct.Unmarshal(dat[n:], sref)
 		n += _n
 		o.Body = sref
 		if err != nil {
diff --git a/lib/btrfs/btrfsitem/item_freespacebitmap.go b/lib/btrfs/btrfsitem/item_freespacebitmap.go
index ad46204..742d126 100644
--- a/lib/btrfs/btrfsitem/item_freespacebitmap.go
+++ b/lib/btrfs/btrfsitem/item_freespacebitmap.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -6,13 +6,15 @@ package btrfsitem
 
 // key.objectid = object ID of the FreeSpaceInfo (logical_addr)
 // key.offset = offset of the FreeSpaceInfo (size)
-type FreeSpaceBitmap []byte // FREE_SPACE_BITMAP=200
+type FreeSpaceBitmap struct { // FREE_SPACE_BITMAP=200
+	Bitmap []byte
+}
 
 func (o *FreeSpaceBitmap) UnmarshalBinary(dat []byte) (int, error) {
-	*o = dat
+	o.Bitmap = dat
 	return len(dat), nil
 }
 
 func (o FreeSpaceBitmap) MarshalBinary() ([]byte, error) {
-	return []byte(o), nil
+	return o.Bitmap, nil
 }
diff --git a/lib/btrfs/btrfsitem/item_inoderef.go b/lib/btrfs/btrfsitem/item_inoderef.go
index 083f19e..c90fe44 100644
--- a/lib/btrfs/btrfsitem/item_inoderef.go
+++ b/lib/btrfs/btrfsitem/item_inoderef.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -16,10 +16,12 @@ import (
 //
 // Might have multiple entries if the same file has multiple hardlinks
 // in the same directory.
-type InodeRefs []InodeRef // INODE_REF=12
+type InodeRefs struct { // INODE_REF=12
+	Refs []InodeRef
+}
 
 func (o *InodeRefs) UnmarshalBinary(dat []byte) (int, error) {
-	*o = nil
+	o.Refs = nil
 	n := 0
 	for n < len(dat) {
 		var ref InodeRef
@@ -28,14 +30,14 @@ func (o *InodeRefs) UnmarshalBinary(dat []byte) (int, error) {
 		if err != nil {
 			return n, err
 		}
-		*o = append(*o, ref)
+		o.Refs = append(o.Refs, ref)
 	}
 	return n, nil
 }
 
 func (o InodeRefs) MarshalBinary() ([]byte, error) {
 	var dat []byte
-	for _, ref := range o {
+	for _, ref := range o.Refs {
 		_dat, err := binstruct.Marshal(ref)
 		dat = append(dat, _dat...)
 		if err != nil {
diff --git a/lib/btrfs/btrfsitem/items.go b/lib/btrfs/btrfsitem/items.go
index 67f96fa..9964e2d 100644
--- a/lib/btrfs/btrfsitem/items.go
+++ b/lib/btrfs/btrfsitem/items.go
@@ -25,7 +25,7 @@ type Error struct {
 	Err error
 }
 
-func (Error) isItem() {}
+func (*Error) isItem() {}
 
 func (o Error) MarshalBinary() ([]byte, error) {
 	return o.Dat, nil
@@ -43,7 +43,7 @@ func UnmarshalItem(key btrfsprim.Key, csumType btrfssum.CSumType, dat []byte) It
 		var ok bool
 		gotyp, ok = untypedObjID2gotype[key.ObjectID]
 		if !ok {
-			return Error{
+			return &Error{
 				Dat: dat,
 				Err: fmt.Errorf("btrfsitem.UnmarshalItem({ItemType:%v, ObjectID:%v}, dat): unknown object ID for untyped item",
 					key.ItemType, key.ObjectID),
@@ -53,31 +53,31 @@ func UnmarshalItem(key btrfsprim.Key, csumType btrfssum.CSumType, dat []byte) It
 		var ok bool
 		gotyp, ok = keytype2gotype[key.ItemType]
 		if !ok {
-			return Error{
+			return &Error{
 				Dat: dat,
 				Err: fmt.Errorf("btrfsitem.UnmarshalItem({ItemType:%v}, dat): unknown item type", key.ItemType),
 			}
 		}
 	}
-	retPtr := reflect.New(gotyp)
-	if csums, ok := retPtr.Interface().(*ExtentCSum); ok {
+	ptr := reflect.New(gotyp)
+	if csums, ok := ptr.Interface().(*ExtentCSum); ok {
 		csums.ChecksumSize = csumType.Size()
 		csums.Addr = btrfsvol.LogicalAddr(key.Offset)
 	}
-	n, err := binstruct.Unmarshal(dat, retPtr.Interface())
+	n, err := binstruct.Unmarshal(dat, ptr.Interface())
 	if err != nil {
-		return Error{
+		return &Error{
 			Dat: dat,
 			Err: fmt.Errorf("btrfsitem.UnmarshalItem({ItemType:%v}, dat): %w", key.ItemType, err),
 		}
 	}
 	if n < len(dat) {
-		return Error{
+		return &Error{
 			Dat: dat,
 			Err: fmt.Errorf("btrfsitem.UnmarshalItem({ItemType:%v}, dat): left over data: got %v bytes but only consumed %v",
 				key.ItemType, len(dat), n),
 		}
 	}
 	//nolint:forcetypeassert // items_gen.go has all types in keytype2gotype implement the Item interface.
-	return retPtr.Elem().Interface().(Item)
+	return ptr.Interface().(Item)
 }
diff --git a/lib/btrfs/btrfsitem/items_gen.go b/lib/btrfs/btrfsitem/items_gen.go
index 9daef81..21c6795 100644
--- a/lib/btrfs/btrfsitem/items_gen.go
+++ b/lib/btrfs/btrfsitem/items_gen.go
@@ -80,27 +80,27 @@ var untypedObjID2gotype = map[btrfsprim.ObjID]reflect.Type{
 	btrfsprim.FREE_SPACE_OBJECTID: reflect.TypeOf(FreeSpaceHeader{}),
 }
 
-func (BlockGroup) isItem()      {}
-func (Chunk) isItem()           {}
-func (Dev) isItem()             {}
-func (DevExtent) isItem()       {}
-func (DevStats) isItem()        {}
-func (DirEntry) isItem()        {}
-func (Empty) isItem()           {}
-func (Extent) isItem()          {}
-func (ExtentCSum) isItem()      {}
-func (ExtentDataRef) isItem()   {}
-func (FileExtent) isItem()      {}
-func (FreeSpaceBitmap) isItem() {}
-func (FreeSpaceHeader) isItem() {}
-func (FreeSpaceInfo) isItem()   {}
-func (Inode) isItem()           {}
-func (InodeRefs) isItem()       {}
-func (Metadata) isItem()        {}
-func (QGroupInfo) isItem()      {}
-func (QGroupLimit) isItem()     {}
-func (QGroupStatus) isItem()    {}
-func (Root) isItem()            {}
-func (RootRef) isItem()         {}
-func (SharedDataRef) isItem()   {}
-func (UUIDMap) isItem()         {}
+func (*BlockGroup) isItem()      {}
+func (*Chunk) isItem()           {}
+func (*Dev) isItem()             {}
+func (*DevExtent) isItem()       {}
+func (*DevStats) isItem()        {}
+func (*DirEntry) isItem()        {}
+func (*Empty) isItem()           {}
+func (*Extent) isItem()          {}
+func (*ExtentCSum) isItem()      {}
+func (*ExtentDataRef) isItem()   {}
+func (*FileExtent) isItem()      {}
+func (*FreeSpaceBitmap) isItem() {}
+func (*FreeSpaceHeader) isItem() {}
+func (*FreeSpaceInfo) isItem()   {}
+func (*Inode) isItem()           {}
+func (*InodeRefs) isItem()       {}
+func (*Metadata) isItem()        {}
+func (*QGroupInfo) isItem()      {}
+func (*QGroupLimit) isItem()     {}
+func (*QGroupStatus) isItem()    {}
+func (*Root) isItem()            {}
+func (*RootRef) isItem()         {}
+func (*SharedDataRef) isItem()   {}
+func (*UUIDMap) isItem()         {}