Setup for differnet types of compression for Writer

Added some TODOs

internal/compression/gzip.go

@@ -15,23 +15,21 @@ type gzipInit struct {
 
 //Gzip is a decompressor for gzip type compression. Uses zlib for compression and decompression
 type Gzip struct {
-	CompressionLevel int32
+	gzipInit
-	HasCustomWindow  bool
+	HasCustomWindow bool
-	HasStrategies    bool
+	HasStrategies   bool
 }
 
 //NewGzipCompressorWithOptions creates a new gzip compressor/decompressor with options read from the given reader.
 func NewGzipCompressorWithOptions(r io.Reader) (*Gzip, error) {
 	var gzip Gzip
-	var init gzipInit
+	err := binary.Read(r, binary.LittleEndian, &gzip.gzipInit)
-	err := binary.Read(r, binary.LittleEndian, &init)
 	if err != nil {
 		return nil, err
 	}
-	gzip.CompressionLevel = init.CompressionLevel
 	//TODO: proper support for window size and strategies
-	gzip.HasCustomWindow = init.WindowSize != 15
+	gzip.HasCustomWindow = gzip.WindowSize != 15
-	gzip.HasStrategies = init.Strategies != 0 && init.Strategies != 1
+	gzip.HasStrategies = gzip.Strategies != 0 && gzip.Strategies != 1
 	return &gzip, nil
 }
 
@@ -58,9 +56,6 @@ func (g *Gzip) Compress(data []byte) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	err = wrt.Flush()
+	wrt.Close()
-	if err != nil {
-		return nil, err
-	}
 	return buf.Bytes(), nil
 }

internal/compression/lz4.go

@@ -35,3 +35,21 @@ func (l *Lz4) Decompress(r io.Reader) ([]byte, error) {
 	_, err := io.Copy(&buf, rdr)
 	return buf.Bytes(), err
 }
+
+//Compress implements compression.Compress
+func (l *Lz4) Compress(data []byte) ([]byte, error) {
+	var buf bytes.Buffer
+	w := lz4.NewWriter(&buf)
+	if l.HC {
+		err := w.Apply(lz4.CompressionLevelOption(lz4.Level9))
+		if err != nil {
+			return nil, err
+		}
+	}
+	_, err := w.Write(data)
+	if err != nil {
+		return nil, err
+	}
+	w.Close()
+	return buf.Bytes(), nil
+}

internal/compression/lzma.go

@@ -23,3 +23,18 @@ func (l *Lzma) Decompress(rdr io.Reader) ([]byte, error) {
 	}
 	return buf.Bytes(), nil
 }
+
+//Compress implements compression.Compress
+func (l *Lzma) Compress(data []byte) ([]byte, error) {
+	var buf bytes.Buffer
+	w, err := lzma.NewWriter(&buf)
+	if err != nil {
+		return nil, err
+	}
+	_, err = w.Write(data)
+	if err != nil {
+		return nil, err
+	}
+	w.Close()
+	return buf.Bytes(), nil
+}

internal/compression/xz.go

@@ -53,3 +53,23 @@ func (x *Xz) Decompress(rdr io.Reader) ([]byte, error) {
 	}
 	return buf.Bytes(), nil
 }
+
+//Compress implements compression.Compress
+func (x *Xz) Compress(data []byte) ([]byte, error) {
+	var buf bytes.Buffer
+	w, err := xz.NewWriter(&buf)
+	if err != nil {
+		return nil, err
+	}
+	w.DictCap = int(x.DictionarySize)
+	err = w.Verify()
+	if err != nil {
+		return nil, err
+	}
+	_, err = w.Write(data)
+	if err != nil {
+		return nil, err
+	}
+	w.Close()
+	return buf.Bytes(), nil
+}

internal/compression/zstd.go

@@ -34,3 +34,18 @@ func (z *Zstd) Decompress(r io.Reader) ([]byte, error) {
 	_, err = io.Copy(&buf, rdr)
 	return buf.Bytes(), err
 }
+
+//Compress impelements compression.Compress
+func (z *Zstd) Compress(data []byte) ([]byte, error) {
+	var buf bytes.Buffer
+	w, err := zstd.NewWriter(&buf, zstd.WithEncoderLevel(zstd.EncoderLevel(z.CompressionLevel)))
+	if err != nil {
+		return nil, err
+	}
+	_, err = w.Write(data)
+	if err != nil {
+		return nil, err
+	}
+	w.Close()
+	return buf.Bytes(), nil
+}

reader.go

@@ -77,9 +77,6 @@ func NewSquashfsReader(r io.ReaderAt) (*Reader, error) {
 			if err != nil {
 				return nil, err
 			}
-			if lz4.HC {
-				hasUnsupportedOptions = true
-			}
 			rdr.decompressor = lz4
 		case ZstdCompression:
 			zstd, err := compression.NewZstdCompressorWithOptions(io.NewSectionReader(rdr.r, int64(binary.Size(rdr.super)), 4))

writer.go

@@ -7,6 +7,8 @@ import (
 	"os"
 	"path"
 	"strings"
+
+	"github.com/CalebQ42/squashfs/internal/compression"
 )
 
 type fileHolder struct {
@@ -14,6 +16,8 @@ type fileHolder struct {
 	path        string
 	name        string
 	symLocation string
+	UID         int
+	GUID        int
 	folder      bool
 	symlink     bool
 }
@@ -21,19 +25,37 @@ type fileHolder struct {
 //Writer is used to creaste squashfs archives. Currently unusable
 //TODO: Make usable
 type Writer struct {
+	compressor      compression.Compressor
 	structure       map[string][]*fileHolder
 	symlinkTable    map[string]string //[oldpath]newpath
+	superblock      superblock
 	compressionType int
-	allowErrors     bool //AllowErrors allows errors when adding folders and their children.
+	allowErrors     bool
 }
 
-//NewWriter creates a new
+//NewWriter creates a new with the default options (Gzip compression and allow errors)
 func NewWriter() (*Writer, error) {
 	return NewWriterWithOptions(GzipCompression, true)
 }
 
+//NewWriterWithOptions creates a new squashfs.Writer with the given options.
+//compressionType can be of any types, except LZO (which this library doesn't have support for yet)
+//allowErrors determines if, when adding folders, it allows errors encountered with it's sub-directories and instead logs the errors.
 func NewWriterWithOptions(compressionType int, allowErrors bool) (*Writer, error) {
-
+	if compressionType < 0 || compressionType > 6 {
+		return nil, errors.New("Incorrect compression type")
+	}
+	if compressionType == 3 {
+		return nil, errors.New("LZO compression is not (currently) supported")
+	}
+	return &Writer{
+		structure: map[string][]*fileHolder{
+			"/": make([]*fileHolder, 0),
+		},
+		symlinkTable:    make(map[string]string),
+		compressionType: compressionType,
+		allowErrors:     allowErrors,
+	}, nil
 }
 
 //AddFile attempts to add an os.File to the archive at it's root.
@@ -83,7 +105,7 @@ func (w *Writer) AddFileTo(filepath string, file *os.File) error {
 				return err
 			}
 			err = w.AddFileToFolder(holder.path+"/"+holder.name, fil)
-			if err != nil && !w.AllowErrors {
+			if err != nil && !w.allowErrors {
 				for _, dir := range dirsAdded {
 					w.Remove(dir)
 				}
@@ -92,7 +114,7 @@ func (w *Writer) AddFileTo(filepath string, file *os.File) error {
 				log.Println("Error while adding", fil.Name())
 				log.Println(err)
 			}
-			if !w.AllowErrors {
+			if !w.allowErrors {
 				dirsAdded = append(dirsAdded, holder.path+"/"+holder.name)
 			}
 		}
@@ -149,6 +171,7 @@ func (w *Writer) Remove(filepath string) bool {
 //
 //If this is not run before writing, you may end up with broken symlinks.
 func (w *Writer) FixSymlinks() error {
+	//TODO
 	return errors.New("DON'T")
 }
 
@@ -164,5 +187,6 @@ func (w *Writer) WriteToFilename(filepath string) error {
 
 //WriteTo attempts to write the archive to the given io.Writer.
 func (w *Writer) WriteTo(write io.Writer) (int64, error) {
+	//TODO
 	return 0, errors.New("I SAID DON'T")
 }

writer_compression_options.go

@@ -0,0 +1,15 @@
+package squashfs
+
+//TODO: Allow settings the options
+
+// func (w *Writer) SetGzipOptions() error {}
+
+// func (w *Writer) SetLzmaOptions() error {}
+
+// func (w *Writer) SetLzoOptions() error {}
+
+// func (w *Writer) SetXzOptions() error {}
+
+// func (w *Writer) SetLz4Options() error {}
+
+// func (w *Writer) SetZstdOptions() error {}