Do not regenerate cover if already cached (fixes #33)

bookbrowser.go

@@ -72,7 +72,7 @@ func main() {
 			}
 		}
 
-		if fi, err := os.Stat(tempdir); err == nil || fi.IsDir() {
+		if fi, err := os.Stat(tempdir); err == nil || (fi != nil && fi.IsDir()) {
 			noRemoveTempDir = true
 			if tempdir == deftempdir {
 				noRemoveTempDir = false

modules/booklist/booklist.go

@@ -15,6 +15,7 @@ import (
 	"github.com/bamiaux/rez"
 	"github.com/geek1011/BookBrowser/formats"
 	"github.com/geek1011/BookBrowser/models"
+	"github.com/geek1011/BookBrowser/modules/util"
 	zglob "github.com/mattn/go-zglob"
 )
 
@@ -83,63 +84,65 @@ func NewBookListFromDir(dir, coverOutDir string, verbose, nocovers bool) (*BookL
 				coverPath := filepath.Join(coverOutDir, book.ID+".jpg")
 				thumbPath := filepath.Join(coverOutDir, book.ID+"_thumb.jpg")
 
-				coverFile, err := os.Create(coverPath)
-				if err != nil {
-					continue
-				}
-				defer coverFile.Close()
-
-				err = jpeg.Encode(coverFile, cover, nil)
-				if err != nil {
-					continue
-				}
-
-				coverBounds := cover.Bounds()
-				coverWidth := coverBounds.Dx()
-				coverHeight := coverBounds.Dy()
-
-				if coverWidth <= 200 {
-					continue
-				}
-
-				// Scale to fit in 200x900
-				scale := math.Min(float64(200.0/float64(coverWidth)), float64(900.0/float64(coverHeight)))
-
-				// Scale and round down
-				coverWidth = int(float64(coverWidth) * scale)
-				coverHeight = int(float64(coverHeight) * scale)
-
-				r := image.Rect(0, 0, coverWidth, coverHeight)
-				var thumb image.Image
-				switch t := cover.(type) {
-				case *image.YCbCr:
-					thumb = image.NewYCbCr(r, t.SubsampleRatio)
-				case *image.RGBA:
-					thumb = image.NewRGBA(r)
-				case *image.NRGBA:
-					thumb = image.NewNRGBA(r)
-				case *image.Gray:
-					thumb = image.NewGray(r)
-				default:
-					continue
-				}
-
-				// rez.NewLanczos(2.0) is faster, but slower
-				err = rez.Convert(thumb, cover, rez.NewBicubicFilter())
-				if err != nil {
-					fmt.Println(coverWidth, coverHeight, scale, err)
-					continue
-				}
-
-				thumbFile, err := os.Create(thumbPath)
-				if err != nil {
-					continue
-				}
-				defer thumbFile.Close()
-
-				err = jpeg.Encode(thumbFile, thumb, nil)
-				if err != nil {
-					continue
+				if !(util.Exists(coverPath) && util.Exists(thumbPath)) {
+					coverFile, err := os.Create(coverPath)
+					if err != nil {
+						continue
+					}
+					defer coverFile.Close()
+
+					err = jpeg.Encode(coverFile, cover, nil)
+					if err != nil {
+						continue
+					}
+
+					coverBounds := cover.Bounds()
+					coverWidth := coverBounds.Dx()
+					coverHeight := coverBounds.Dy()
+
+					if coverWidth <= 200 {
+						continue
+					}
+
+					// Scale to fit in 200x900
+					scale := math.Min(float64(200.0/float64(coverWidth)), float64(900.0/float64(coverHeight)))
+
+					// Scale and round down
+					coverWidth = int(float64(coverWidth) * scale)
+					coverHeight = int(float64(coverHeight) * scale)
+
+					r := image.Rect(0, 0, coverWidth, coverHeight)
+					var thumb image.Image
+					switch t := cover.(type) {
+					case *image.YCbCr:
+						thumb = image.NewYCbCr(r, t.SubsampleRatio)
+					case *image.RGBA:
+						thumb = image.NewRGBA(r)
+					case *image.NRGBA:
+						thumb = image.NewNRGBA(r)
+					case *image.Gray:
+						thumb = image.NewGray(r)
+					default:
+						continue
+					}
+
+					// rez.NewLanczos(2.0) is faster, but slower
+					err = rez.Convert(thumb, cover, rez.NewBicubicFilter())
+					if err != nil {
+						fmt.Println(coverWidth, coverHeight, scale, err)
+						continue
+					}
+
+					thumbFile, err := os.Create(thumbPath)
+					if err != nil {
+						continue
+					}
+					defer thumbFile.Close()
+
+					err = jpeg.Encode(thumbFile, thumb, nil)
+					if err != nil {
+						continue
+					}
 				}
 
 				book.HasCover = true

modules/util/util.go

@@ -2,6 +2,7 @@ package util
 
 import (
 	"net"
+	"os"
 	"strings"
 )
 
@@ -51,3 +52,9 @@ func GetIP() net.IP {
 
 	return localAddr.IP
 }
+
+// Exists checks whether a path exists
+func Exists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}

modules/util/util_test.go

@@ -21,3 +21,8 @@ func TestStringAfter(t *testing.T) {
 func TestFixString(t *testing.T) {
 	assert.Equal(t, `""""''`, FixString(`“‹”›‘’`))
 }
+
+func TestExists(t *testing.T) {
+	assert.True(t, Exists("."))
+	assert.False(t, Exists("sdfsdfsdf"))
+}