remove pointer from epub zip

internal/epub/zip/epub_zip.go

@@ -17,17 +17,17 @@ type EPUBZip struct {
 }
 
 // New create a new EPUB
-func New(path string) (*EPUBZip, error) {
+func New(path string) (EPUBZip, error) {
 	w, err := os.Create(path)
 	if err != nil {
-		return nil, err
+		return EPUBZip{}, err
 	}
 	wz := zip.NewWriter(w)
-	return &EPUBZip{w, wz}, nil
+	return EPUBZip{w, wz}, nil
 }
 
 // Close compress pipe and file.
-func (e *EPUBZip) Close() error {
+func (e EPUBZip) Close() error {
 	if err := e.wz.Close(); err != nil {
 		return err
 	}
@@ -37,10 +37,10 @@ func (e *EPUBZip) Close() error {
 // WriteMagic Write mimetype, in a very specific way.
 //
 // This will be valid with epubcheck tools.
-func (e *EPUBZip) WriteMagic() error {
+func (e EPUBZip) WriteMagic() error {
 	t := time.Now().UTC()
 	//goland:noinspection GoDeprecation
-	fh := &zip.FileHeader{
+	fh := zip.FileHeader{
 		Name:               "mimetype",
 		Method:             zip.Store,
 		Modified:           t,
@@ -53,7 +53,7 @@ func (e *EPUBZip) WriteMagic() error {
 	fh.CreatorVersion = fh.CreatorVersion&0xff00 | 20 // preserve compatibility byte
 	fh.ReaderVersion = 20
 	fh.SetMode(0600)
-	m, err := e.wz.CreateRaw(fh)
+	m, err := e.wz.CreateRaw(&fh)
 
 	if err != nil {
 		return err
@@ -62,12 +62,12 @@ func (e *EPUBZip) WriteMagic() error {
 	return err
 }
 
-func (e *EPUBZip) Copy(fz *zip.File) error {
+func (e EPUBZip) Copy(fz *zip.File) error {
 	return e.wz.Copy(fz)
 }
 
 // WriteRaw Write image. They are already compressed, so we write them down directly.
-func (e *EPUBZip) WriteRaw(raw *ZipImage) error {
+func (e EPUBZip) WriteRaw(raw ZipImage) error {
 	m, err := e.wz.CreateRaw(raw.Header)
 	if err != nil {
 		return err
@@ -77,7 +77,7 @@ func (e *EPUBZip) WriteRaw(raw *ZipImage) error {
 }
 
 // WriteContent Write file. Compressed it using deflate.
-func (e *EPUBZip) WriteContent(file string, content []byte) error {
+func (e EPUBZip) WriteContent(file string, content []byte) error {
 	m, err := e.wz.CreateHeader(&zip.FileHeader{
 		Name:     file,
 		Modified: time.Now(),

internal/epub/zip/epub_zip_image.go

@@ -18,7 +18,7 @@ type ZipImage struct {
 }
 
 // CompressImage create gzip encoded jpeg
-func CompressImage(filename string, format string, img image.Image, quality int) (*ZipImage, error) {
+func CompressImage(filename string, format string, img image.Image, quality int) (ZipImage, error) {
 	var (
 		data, cdata bytes.Buffer
 		err         error
@@ -33,27 +33,27 @@ func CompressImage(filename string, format string, img image.Image, quality int)
 		err = fmt.Errorf("unknown format %q", format)
 	}
 	if err != nil {
-		return nil, err
+		return ZipImage{}, err
 	}
 
 	wcdata, err := flate.NewWriter(&cdata, flate.BestCompression)
 	if err != nil {
-		return nil, err
+		return ZipImage{}, err
 	}
 
 	_, err = wcdata.Write(data.Bytes())
 	if err != nil {
-		return nil, err
+		return ZipImage{}, err
 	}
 
 	err = wcdata.Close()
 	if err != nil {
-		return nil, err
+		return ZipImage{}, err
 	}
 
 	t := time.Now()
 	//goland:noinspection GoDeprecation
-	return &ZipImage{
+	return ZipImage{
 		&zip.FileHeader{
 			Name:               filename,
 			CompressedSize64:   uint64(cdata.Len()),

internal/epub/zip/epub_zip_storage_image.go

@@ -14,16 +14,16 @@ type StorageImageWriter struct {
 	mut    *sync.Mutex
 }
 
-func NewStorageImageWriter(filename string, format string) (*StorageImageWriter, error) {
+func NewStorageImageWriter(filename string, format string) (StorageImageWriter, error) {
 	fh, err := os.Create(filename)
 	if err != nil {
-		return nil, err
+		return StorageImageWriter{}, err
 	}
 	fz := zip.NewWriter(fh)
-	return &StorageImageWriter{fh, fz, format, &sync.Mutex{}}, nil
+	return StorageImageWriter{fh, fz, format, &sync.Mutex{}}, nil
 }
 
-func (e *StorageImageWriter) Close() error {
+func (e StorageImageWriter) Close() error {
 	if err := e.fz.Close(); err != nil {
 		_ = e.fh.Close()
 		return err
@@ -31,7 +31,7 @@ func (e *StorageImageWriter) Close() error {
 	return e.fh.Close()
 }
 
-func (e *StorageImageWriter) Add(filename string, img image.Image, quality int) error {
+func (e StorageImageWriter) Add(filename string, img image.Image, quality int) error {
 	zipImage, err := CompressImage(filename, e.format, img, quality)
 	if err != nil {
 		return err
@@ -59,42 +59,41 @@ type StorageImageReader struct {
 	files map[string]*zip.File
 }
 
-func NewStorageImageReader(filename string) (*StorageImageReader, error) {
+func NewStorageImageReader(filename string) (StorageImageReader, error) {
 	fh, err := os.Open(filename)
 	if err != nil {
-		return nil, err
+		return StorageImageReader{}, err
 	}
 	s, err := fh.Stat()
 	if err != nil {
-		return nil, err
+		return StorageImageReader{}, err
 	}
 	fz, err := zip.NewReader(fh, s.Size())
 	if err != nil {
-		return nil, err
+		return StorageImageReader{}, err
 	}
 	files := map[string]*zip.File{}
 	for _, z := range fz.File {
 		files[z.Name] = z
 	}
-	return &StorageImageReader{filename, fh, fz, files}, nil
+	return StorageImageReader{filename, fh, fz, files}, nil
 }
 
-func (e *StorageImageReader) Get(filename string) *zip.File {
+func (e StorageImageReader) Get(filename string) *zip.File {
 	return e.files[filename]
 }
 
-func (e *StorageImageReader) Size(filename string) uint64 {
-	img := e.Get(filename)
-	if img != nil {
+func (e StorageImageReader) Size(filename string) uint64 {
+	if img, ok := e.files[filename]; ok {
 		return img.CompressedSize64 + 30 + uint64(len(img.Name))
 	}
 	return 0
 }
 
-func (e *StorageImageReader) Close() error {
+func (e StorageImageReader) Close() error {
 	return e.fh.Close()
 }
 
-func (e *StorageImageReader) Remove() error {
+func (e StorageImageReader) Remove() error {
 	return os.Remove(e.filename)
 }