缩略图生成器支持 LibRaw (#2109)

* feat: 增加 LibRaw 缩略图生成器。

* feat: 生成 RAW 图像的缩略图时，旋转缩略图的方向。

* update: RAW 缩略图支持镜像方向。

models/defaults.go

@@ -121,6 +121,9 @@ Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; verti
 	{Name: "thumb_proxy_enabled", Value: "0", Type: "thumb"},
 	{Name: "thumb_proxy_policy", Value: "[]", Type: "thumb"},
 	{Name: "thumb_max_src_size", Value: "31457280", Type: "thumb"},
+	{Name: "thumb_libraw_path", Value: "simple_dcraw", Type: "thumb"},
+	{Name: "thumb_libraw_enabled", Value: "0", Type: "thumb"},
+	{Name: "thumb_libraw_exts", Value: "arw,raf,dng", Type: "thumb"},
 	{Name: "pwa_small_icon", Value: "/static/img/favicon.ico", Type: "pwa"},
 	{Name: "pwa_medium_icon", Value: "/static/img/logo192.png", Type: "pwa"},
 	{Name: "pwa_large_icon", Value: "/static/img/logo512.png", Type: "pwa"},

pkg/filesystem/image.go

@@ -145,6 +145,7 @@ func (fs *FileSystem) generateThumbnail(ctx context.Context, file *model.File) e
 		"thumb_vips_enabled",
 		"thumb_ffmpeg_enabled",
 		"thumb_libreoffice_enabled",
+		"thumb_libraw_enabled",
 	))
 	if err != nil {
 		_ = updateThumbStatus(file, model.ThumbStatusNotAvailable)

pkg/thumb/libraw.go

@@ -0,0 +1,283 @@
+package thumb
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"image"
+	"image/jpeg"
+	"image/png"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	model "github.com/cloudreve/Cloudreve/v3/models"
+	"github.com/cloudreve/Cloudreve/v3/pkg/util"
+	"github.com/gofrs/uuid"
+)
+
+func init() {
+	RegisterGenerator(&LibRawGenerator{})
+}
+
+type LibRawGenerator struct {
+	exts        []string
+	lastRawExts string
+}
+
+func (f *LibRawGenerator) Generate(ctx context.Context, file io.Reader, _ string, name string, options map[string]string) (*Result, error) {
+	const (
+		thumbLibRawPath = "thumb_libraw_path"
+		thumbLibRawExt  = "thumb_libraw_exts"
+		thumbTempPath   = "temp_path"
+	)
+
+	opts := model.GetSettingByNames(thumbLibRawPath, thumbLibRawExt, thumbTempPath)
+
+	if f.lastRawExts != opts[thumbLibRawExt] {
+		f.exts = strings.Split(opts[thumbLibRawExt], ",")
+		f.lastRawExts = opts[thumbLibRawExt]
+	}
+
+	if !util.IsInExtensionList(f.exts, name) {
+		return nil, fmt.Errorf("unsupported image format: %w", ErrPassThrough)
+	}
+
+	inputFilePath := filepath.Join(
+		util.RelativePath(opts[thumbTempPath]),
+		"thumb",
+		fmt.Sprintf("thumb_%s", uuid.Must(uuid.NewV4()).String()),
+	)
+	defer func() { _ = os.Remove(inputFilePath) }()
+
+	inputFile, err := util.CreatNestedFile(inputFilePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create temp file: %w", err)
+	}
+
+	if _, err = io.Copy(inputFile, file); err != nil {
+		_ = inputFile.Close()
+		return nil, fmt.Errorf("failed to write input file: %w", err)
+	}
+	_ = inputFile.Close()
+
+	cmd := exec.CommandContext(ctx, opts[thumbLibRawPath], "-e", inputFilePath)
+
+	var stdErr bytes.Buffer
+	cmd.Stderr = &stdErr
+	if err = cmd.Run(); err != nil {
+		util.Log().Warning("Failed to invoke LibRaw: %s", stdErr.String())
+		return nil, fmt.Errorf("failed to invoke LibRaw: %w", err)
+	}
+
+	outputFilePath := inputFilePath + ".thumb.jpg"
+	defer func() { _ = os.Remove(outputFilePath) }()
+
+	ff, err := os.Open(outputFilePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open temp file: %w", err)
+	}
+	defer func() { _ = ff.Close() }()
+
+	// use builtin generator
+	result, err := new(Builtin).Generate(ctx, ff, outputFilePath, filepath.Base(outputFilePath), options)
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate thumbnail: %w", err)
+	}
+
+	orientation, err := getJpegOrientation(outputFilePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get jpeg orientation: %w", err)
+	}
+	if orientation == 1 {
+		return result, nil
+	}
+
+	if err = rotateImg(result.Path, orientation); err != nil {
+		return nil, fmt.Errorf("failed to rotate image: %w", err)
+	}
+	return result, nil
+}
+
+func rotateImg(filePath string, orientation int) error {
+	resultImg, err := os.OpenFile(filePath, os.O_RDWR, 0777)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = resultImg.Close() }()
+
+	imgFlag := make([]byte, 3)
+	if _, err = io.ReadFull(resultImg, imgFlag); err != nil {
+		return err
+	}
+	if _, err = resultImg.Seek(0, 0); err != nil {
+		return err
+	}
+
+	var img image.Image
+	if bytes.Equal(imgFlag, []byte{0xFF, 0xD8, 0xFF}) {
+		img, err = jpeg.Decode(resultImg)
+	} else {
+		img, err = png.Decode(resultImg)
+	}
+	if err != nil {
+		return err
+	}
+
+	switch orientation {
+	case 8:
+		img = rotate90(img)
+	case 3:
+		img = rotate90(rotate90(img))
+	case 6:
+		img = rotate90(rotate90(rotate90(img)))
+	case 2:
+		img = mirrorImg(img)
+	case 7:
+		img = rotate90(mirrorImg(img))
+	case 4:
+		img = rotate90(rotate90(mirrorImg(img)))
+	case 5:
+		img = rotate90(rotate90(rotate90(mirrorImg(img))))
+	}
+
+	if err = resultImg.Truncate(0); err != nil {
+		return err
+	}
+	if _, err = resultImg.Seek(0, 0); err != nil {
+		return err
+	}
+
+	if bytes.Equal(imgFlag, []byte{0xFF, 0xD8, 0xFF}) {
+		return jpeg.Encode(resultImg, img, nil)
+	}
+	return png.Encode(resultImg, img)
+}
+
+func getJpegOrientation(fileName string) (int, error) {
+	f, err := os.Open(fileName)
+	if err != nil {
+		return 0, err
+	}
+	defer func() { _ = f.Close() }()
+
+	header := make([]byte, 6)
+	defer func() { header = nil }()
+	if _, err = io.ReadFull(f, header); err != nil {
+		return 0, err
+	}
+
+	// jpeg format header
+	if !bytes.Equal(header[:3], []byte{0xFF, 0xD8, 0xFF}) {
+		return 0, errors.New("not a jpeg")
+	}
+
+	// not a APP1 marker
+	if header[3] != 0xE1 {
+		return 1, nil
+	}
+
+	// exif data total length
+	totalLen := int(header[4])<<8 + int(header[5]) - 2
+	buf := make([]byte, totalLen)
+	defer func() { buf = nil }()
+	if _, err = io.ReadFull(f, buf); err != nil {
+		return 0, err
+	}
+
+	// remove Exif identifier code
+	buf = buf[6:]
+
+	// byte order
+	parse16, parse32, err := initParseMethod(buf[:2])
+	if err != nil {
+		return 0, err
+	}
+
+	// version
+	_ = buf[2:4]
+
+	// first IFD offset
+	offset := parse32(buf[4:8])
+
+	// first DE offset
+	offset += 2
+	buf = buf[offset:]
+
+	const (
+		orientationTag = 0x112
+		deEntryLength  = 12
+	)
+	for len(buf) > deEntryLength {
+		tag := parse16(buf[:2])
+		if tag == orientationTag {
+			return int(parse32(buf[8:12])), nil
+		}
+		buf = buf[deEntryLength:]
+	}
+
+	return 0, errors.New("orientation not found")
+}
+
+func initParseMethod(buf []byte) (func([]byte) int16, func([]byte) int32, error) {
+	if bytes.Equal(buf, []byte{0x49, 0x49}) {
+		return littleEndian16, littleEndian32, nil
+	}
+	if bytes.Equal(buf, []byte{0x4D, 0x4D}) {
+		return bigEndian16, bigEndian32, nil
+	}
+	return nil, nil, errors.New("invalid byte order")
+}
+
+func littleEndian16(buf []byte) int16 {
+	return int16(buf[0]) | int16(buf[1])<<8
+}
+
+func bigEndian16(buf []byte) int16 {
+	return int16(buf[1]) | int16(buf[0])<<8
+}
+
+func littleEndian32(buf []byte) int32 {
+	return int32(buf[0]) | int32(buf[1])<<8 | int32(buf[2])<<16 | int32(buf[3])<<24
+}
+
+func bigEndian32(buf []byte) int32 {
+	return int32(buf[3]) | int32(buf[2])<<8 | int32(buf[1])<<16 | int32(buf[0])<<24
+}
+
+func rotate90(img image.Image) image.Image {
+	bounds := img.Bounds()
+	width, height := bounds.Dx(), bounds.Dy()
+	newImg := image.NewRGBA(image.Rect(0, 0, height, width))
+	for x := 0; x < width; x++ {
+		for y := 0; y < height; y++ {
+			newImg.Set(y, width-x-1, img.At(x, y))
+		}
+	}
+	return newImg
+}
+
+func mirrorImg(img image.Image) image.Image {
+	bounds := img.Bounds()
+	width, height := bounds.Dx(), bounds.Dy()
+	newImg := image.NewRGBA(image.Rect(0, 0, width, height))
+	for x := 0; x < width; x++ {
+		for y := 0; y < height; y++ {
+			newImg.Set(width-x-1, y, img.At(x, y))
+		}
+	}
+	return newImg
+}
+
+func (f *LibRawGenerator) Priority() int {
+	return 250
+}
+
+func (f *LibRawGenerator) EnableFlag() string {
+	return "thumb_libraw_enabled"
+}
+
+var _ Generator = (*LibRawGenerator)(nil)

pkg/thumb/tester.go

@@ -23,6 +23,8 @@ func TestGenerator(ctx context.Context, name, executable string) (string, error)
 		return testFfmpegGenerator(ctx, executable)
 	case "libreOffice":
 		return testLibreOfficeGenerator(ctx, executable)
+	case "libRaw":
+		return testLibRawGenerator(ctx, executable)
 	default:
 		return "", ErrUnknownGenerator
 	}
@@ -72,3 +74,18 @@ func testLibreOfficeGenerator(ctx context.Context, executable string) (string, e
 
 	return output.String(), nil
 }
+
+func testLibRawGenerator(ctx context.Context, executable string) (string, error) {
+	cmd := exec.CommandContext(ctx, executable)
+	var output bytes.Buffer
+	cmd.Stdout = &output
+	if err := cmd.Run(); err != nil {
+		return "", fmt.Errorf("failed to invoke libraw executable: %w", err)
+	}
+
+	if !strings.Contains(output.String(), "LibRaw") {
+		return "", ErrUnknownOutput
+	}
+
+	return output.String(), nil
+}