Tweaks to make FromReader work

internal/rawreader/rawreader.go

@@ -1,23 +1,28 @@
 package rawreader
 
 import (
+	"bytes"
 	"errors"
 	"io"
 )
 
-func ConvertReader(r io.Reader) RawReader {
+func ConvertReader(r io.Reader) (RawReader, error) {
 	if rr, ok := r.(RawReader); ok {
-		return rr
+		return rr, nil
 	}
 	if rs, is := r.(io.ReadSeeker); is {
 		return &fromReadSeeker{
 			ReadSeeker: rs,
+		}, nil
 	}
+	buf := new(bytes.Buffer)
+	_, err := io.Copy(buf, r)
+	if err != nil {
+		return nil, err
 	}
 	return &fromReader{
-		rdr:   r,
+		data: buf.Bytes(),
-		cache: make([]byte, 0),
+	}, nil
-	}
 }
 
 func ConvertReaderAt(r io.ReaderAt) RawReader {
@@ -37,27 +42,21 @@ type RawReader interface {
 }
 
 type fromReader struct {
-	rdr   io.Reader
+	data []byte
-	cache []byte
 	off  int
 }
 
-func (r *fromReader) increaseCache(len int) error {
-	newCache := make([]byte, len)
-	_, err := r.rdr.Read(newCache)
-	if err != nil {
-		return err
-	}
-	r.cache = append(r.cache, newCache...)
-	return nil
-}
-
 func (r *fromReader) ReadAt(p []byte, off int64) (n int, err error) {
-	if int(off)+len(p) > len(r.cache) {
+	n = len(p)
-		r.increaseCache((int(off) + len(p)) - len(r.cache))
+	if int(off)+len(p) > len(r.data) {
+		n = len(r.data) - int(off)
+		err = io.EOF
 	}
-	for i := int64(0); i < int64(len(p)); i++ {
+	if n < 0 {
-		p[i] = r.cache[off+i]
+		n = 0
+	}
+	for i := 0; i < n; i++ {
+		p[i] = r.data[int(off)+i]
 	}
 	return
 }
@@ -65,32 +64,35 @@ func (r *fromReader) ReadAt(p []byte, off int64) (n int, err error) {
 func (r *fromReader) Seek(off int64, whence int) (n int64, err error) {
 	switch whence {
 	case io.SeekEnd:
-		return 0, errors.New("cannot SeekEnd RawReader")
+		r.off = len(r.data) - int(off)
+		if r.off < 0 {
+			r.off = 0
+			err = io.EOF
+		}
 	case io.SeekCurrent:
 		r.off += int(off)
 	case io.SeekStart:
 		r.off = int(off)
 	}
-	if r.off > len(r.cache) {
+	if r.off > len(r.data) {
-		err = r.increaseCache(len(r.cache) - r.off)
+		r.off = len(r.data)
-		if err != nil {
+		return int64(r.off), io.EOF
-			r.off = len(r.cache)
-		}
 	}
 	return int64(r.off), err
 }
 
 func (r *fromReader) Read(p []byte) (n int, err error) {
-	if len(p)+r.off > len(r.cache) {
+	n = len(p)
-		err = r.increaseCache((len(p) + r.off) - len(r.cache))
+	if r.off+len(p) > len(r.data) {
-		if err != nil {
+		n = len(r.data) - r.off
-			return
+		err = io.EOF
 	}
+	if n < 0 {
+		n = 0
 	}
-	for i := 0; i < len(p); i++ {
+	for i := 0; i < n; i++ {
-		p[i] = r.cache[r.off+i]
+		p[i] = r.data[r.off+i]
 	}
-	r.off += len(p)
 	return
 }
 

reader.go

@@ -46,12 +46,18 @@ func NewSquashfsReader(r io.ReaderAt) (*Reader, error) {
 }
 
 //NewSquashfsReaderFromReader returns a new squashfs.Reader from an io.Reader.
-//If possible, try to use a io.ReaderAt.
+//If the io.Reader implements io.Seeker, the seek functions are used.
-//With an io.Reader, much of the data has to be cached to memory.
+//It is NOT recommended to use a pure io.Reader as due to how squashfs
+//archives are formatted, the ENTIRETY of the io.Reader's data is loaded into
+//memory first before it can be used.
 func NewSquashfsReaderFromReader(r io.Reader) (*Reader, error) {
 	var rdr Reader
-	rdr.r = rawreader.ConvertReader(r)
+	var err error
-	err := rdr.Init()
+	rdr.r, err = rawreader.ConvertReader(r)
+	if err != nil {
+		return nil, err
+	}
+	err = rdr.Init()
 	if err != nil {
 		return nil, err
 	}
@@ -145,7 +151,10 @@ func (r *Reader) Init() error {
 	}
 	unread := r.super.IDCount
 	blockOffsets := make([]uint64, int(math.Ceil(float64(r.super.IDCount)/2048)))
-	r.r.Seek(int64(r.super.IDTableStart), io.SeekStart)
+	_, err = r.r.Seek(int64(r.super.IDTableStart), io.SeekStart)
+	if err != nil {
+		return err
+	}
 	for i := range blockOffsets {
 		err = binary.Read(r.r, binary.LittleEndian, &blockOffsets[i])
 		if err != nil {

reader_test.go

@@ -40,25 +40,13 @@ func TestSquashfs(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	os.RemoveAll(wd + "/testing/" + squashfsName + ".d")
 	op := DefaultOptions()
 	op.Verbose = true
 	err = rdr.ExtractWithOptions(wd+"/testing/"+squashfsName+".d", op)
 	if err != nil {
 		t.Fatal(err)
 	}
-	fmt.Println("stuff", rdr.super.CompressionType)
-	// fil := rdr.GetFileAtPath("*.desktop")
-	// if fil == nil {
-	// 	t.Fatal("Can't find desktop fil")
-	// }
-	// errs := fil.ExtractTo(wd + "/testing")
-	// if len(errs) > 0 {
-	// 	t.Fatal(errs)
-	// }
-	// errs = rdr.ExtractTo(wd + "/testing/" + squashfsName + ".d")
-	// if len(errs) > 0 {
-	// 	t.Fatal(errs)
-	// }
 	t.Fatal("No Problems")
 }
 
@@ -72,6 +60,7 @@ func TestSquashfsFromReader(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	os.RemoveAll("testing/" + squashfsName + ".d")
 	op := DefaultOptions()
 	op.Verbose = true
 	err = rdr.ExtractWithOptions("testing/"+squashfsName+".d", op)