Better disabling of compression types

internal/decompress/get_decomp.go

@@ -1,34 +0,0 @@
-//go:build !no_gpl && !no_obsolete
-
-package decompress
-
-import "errors"
-
-// The types of compression supported by squashfs
-const (
-	ZlibCompression = uint16(iota + 1)
-	LZMACompression
-	LZOCompression
-	XZCompression
-	LZ4Compression
-	ZSTDCompression
-)
-
-func GetDecompressor(compType uint16) (Decompressor, error) {
-	switch compType {
-	case ZlibCompression:
-		return Zlib{}, nil
-	case LZMACompression:
-		return Lzma{}, nil
-	case LZOCompression:
-		return Lzo{}, nil
-	case XZCompression:
-		return Xz{}, nil
-	case LZ4Compression:
-		return Lz4{}, nil
-	case ZSTDCompression:
-		return &Zstd{}, nil
-	default:
-		return nil, errors.New("invalid compression type. possible corrupted archive")
-	}
-}

internal/decompress/get_decomp_no_gpl.go

@@ -1,34 +0,0 @@
-//go:build no_gpl && !no_obsolete
-
-package decompress
-
-import "errors"
-
-// The types of compression supported by squashfs
-const (
-	ZlibCompression = uint16(iota + 1)
-	LZMACompression
-	LZOCompression
-	XZCompression
-	LZ4Compression
-	ZSTDCompression
-)
-
-func GetDecompressor(compType uint16) (Decompressor, error) {
-	switch compType {
-	case ZlibCompression:
-		return Zlib{}, nil
-	case LZMACompression:
-		return Lzma{}, nil
-	case LZOCompression:
-		return nil, errors.New("lzo compression is disable in this build with no_gpl")
-	case XZCompression:
-		return Xz{}, nil
-	case LZ4Compression:
-		return Lz4{}, nil
-	case ZSTDCompression:
-		return &Zstd{}, nil
-	default:
-		return nil, errors.New("invalid compression type. possible corrupted archive")
-	}
-}

internal/decompress/get_decomp_no_gpl_obsolete.go

@@ -1,34 +0,0 @@
-//go:build no_obsolete && !no_gpl
-
-package decompress
-
-import "errors"
-
-// The types of compression supported by squashfs
-const (
-	ZlibCompression = uint16(iota + 1)
-	LZMACompression
-	LZOCompression
-	XZCompression
-	LZ4Compression
-	ZSTDCompression
-)
-
-func GetDecompressor(compType uint16) (Decompressor, error) {
-	switch compType {
-	case ZlibCompression:
-		return Zlib{}, nil
-	case LZMACompression:
-		return nil, errors.New("lzma compression is disable in this build with no_obsolete")
-	case LZOCompression:
-		return Lzo{}, nil
-	case XZCompression:
-		return Xz{}, nil
-	case LZ4Compression:
-		return Lz4{}, nil
-	case ZSTDCompression:
-		return &Zstd{}, nil
-	default:
-		return nil, errors.New("invalid compression type. possible corrupted archive")
-	}
-}

internal/decompress/get_decomp_no_obsolete.go

@@ -1,34 +0,0 @@
-//go:build no_gpl && no_obsolete
-
-package decompress
-
-import "errors"
-
-// The types of compression supported by squashfs
-const (
-	ZlibCompression = uint16(iota + 1)
-	LZMACompression
-	LZOCompression
-	XZCompression
-	LZ4Compression
-	ZSTDCompression
-)
-
-func GetDecompressor(compType uint16) (Decompressor, error) {
-	switch compType {
-	case ZlibCompression:
-		return Zlib{}, nil
-	case LZMACompression:
-		return nil, errors.New("lzma compression is disable in this build with no_obsolete")
-	case LZOCompression:
-		return nil, errors.New("lzo compression is disable in this build with no_gpl")
-	case XZCompression:
-		return Xz{}, nil
-	case LZ4Compression:
-		return Lz4{}, nil
-	case ZSTDCompression:
-		return &Zstd{}, nil
-	default:
-		return nil, errors.New("invalid compression type. possible corrupted archive")
-	}
-}

internal/decompress/lzma.go

@@ -11,6 +11,10 @@ import (
 
 type Lzma struct{}
 
+func NewLzma() (Lzma, error) {
+	return Lzma{}, nil
+}
+
 func (l Lzma) Decompress(data []byte) ([]byte, error) {
 	rdr, err := lzma.NewReader(bytes.NewReader(data))
 	if err != nil {

internal/decompress/lzma_disabled.go

@@ -0,0 +1,17 @@
+//go:build no_obsolete
+
+package decompress
+
+import (
+	"errors"
+)
+
+type Lzma struct{}
+
+func NewLzma() (Lzma, error) {
+	return Lzma{}, errors.New("lzma compression is disable in this build with no_obsolete")
+}
+
+func (l Lzma) Decompress(data []byte) ([]byte, error) {
+	return nil, errors.New("lzma compression is disable in this build with no_obsolete")
+}

internal/decompress/lzo.go

@@ -10,6 +10,10 @@ import (
 
 type Lzo struct{}
 
+func NewLzo() (Lzo, error) {
+	return Lzo{}, nil
+}
+
 func (l Lzo) Decompress(data []byte) ([]byte, error) {
 	return lzo.Decompress1X(bytes.NewReader(data), len(data), 0)
 }

internal/decompress/lzo_disabled.go

@@ -0,0 +1,15 @@
+//go:build no_gpl
+
+package decompress
+
+import "errors"
+
+type Lzo struct{}
+
+func NewLzo() (Lzo, error) {
+	return Lzo{}, errors.New("lzo compression is disable in this build with no_gpl")
+}
+
+func (l Lzo) Decompress(data []byte) ([]byte, error) {
+	return nil, errors.New("lzo compression is disable in this build with no_gpl")
+}

low/reader.go

@@ -55,9 +55,27 @@ func NewReader(r io.ReaderAt) (rdr *Reader, err error) {
 	if !rdr.Superblock.ValidVersion() {
 		return nil, ErrorVersion
 	}
-	rdr.d, err = decompress.GetDecompressor(rdr.Superblock.CompType)
+	switch rdr.Superblock.CompType {
-	if err != nil {
+	case ZlibCompression:
-		return nil, err
+		rdr.d = decompress.Zlib{}
+	case LZMACompression:
+		rdr.d, err = decompress.NewLzma()
+		if err != nil {
+			return nil, err
+		}
+	case LZOCompression:
+		rdr.d, err = decompress.NewLzo()
+		if err != nil {
+			return nil, err
+		}
+	case XZCompression:
+		rdr.d = decompress.Xz{}
+	case LZ4Compression:
+		rdr.d = decompress.Lz4{}
+	case ZSTDCompression:
+		rdr.d = decompress.Zstd{}
+	default:
+		return nil, errors.New("invalid compression type. possible corrupted archive")
 	}
 	rdr.Root, err = rdr.directoryFromRef(rdr.Superblock.RootInodeRef, "")
 	if err != nil {