Separate image operations to dedicated module

Signed-off-by: Igor Shishkin <me@teran.ru>

src/imgsum/cmd/main.go

@@ -2,53 +2,39 @@ package main
 
 import (
  "bufio"
- "bytes"
- "crypto/sha256"
- "encoding/hex"
  "encoding/json"
  "flag"
  "fmt"
- "image"
- "image/jpeg"
  "io"
  "os"
- "regexp"
  "strings"
 
- "github.com/Soreil/arw"
- "github.com/brett-lempereur/ish"
- "github.com/nf/cr2"
+ "imgsum/image"
 )
 
 type JsonOutput struct {
  Duplicates [][]string `json:"duplicates"`
  Count int `json:"count"`
 }
 
-var (
- re_canon = regexp.MustCompile("(?i).cr(2)$")
- re_sony = regexp.MustCompile("(?i).(arw|sr2)$")
-)
-
-func calculate(file string) error {
- var img image.Image
- img, err := getImage(file)
+func calculate(file string) (error) {
+ i, err := image.NewImage(file)
  if err != nil {
  fmt.Fprintln(os.Stderr, file, err.Error())
  return err
  }
 
- h, err := hash(img)
+ h, err := i.Hexdigest()
  if err != nil {
  fmt.Fprintln(os.Stderr, file, err.Error())
  return err
  }
 
- fmt.Printf("%v %v\n", h, file)
+ fmt.Printf("%v %v\n", h, i.Filename())
  return nil
 }
 
-func checkFiles(checksumFile string) error {
+func check(checksumFile string) error {
  fp, err := os.Open(checksumFile)
  if err != nil {
  fmt.Fprintln(os.Stderr, checksumFile, err.Error())
@@ -61,16 +47,16 @@ func checkFiles(checksumFile string) error {
  for err != io.EOF {
  fields := strings.Fields(line)
  if len(fields) == 2 {
- img, err := getImage(fields[1])
+ i, err := image.NewImage(fields[1])
  if err != nil {
  fmt.Fprintln(os.Stderr, fields[1], err.Error())
- return err
+ continue
  }
 
- h, err := hash(img)
+ h, err := i.Hexdigest()
  if err != nil {
  fmt.Fprintln(os.Stderr, fields[1], err.Error())
- return err
+ continue
  }
 
  if fields[0] == h {
@@ -138,69 +124,6 @@ func deduplicate(filename string, json_output bool) error {
  return nil
 }
 
-func getImage(filename string) (image.Image, error) {
- var img image.Image
- var err error
- var fp *os.File
-
- fp, err = os.Open(filename)
- if err != nil {
- return nil, err
- }
- defer fp.Close()
-
- if re_canon.Match([]byte(filename)) {
- img, err = cr2.Decode(fp)
- } else if re_sony.Match([]byte(filename)) {
- header, err := arw.ParseHeader(fp)
- meta, err := arw.ExtractMetaData(fp, int64(header.Offset), 0)
- if err != nil {
- return nil, err
- }
-
- var jpegOffset uint32
- var jpegLength uint32
- for i := range meta.FIA {
- switch meta.FIA[i].Tag {
- case arw.JPEGInterchangeFormat:
- jpegOffset = meta.FIA[i].Offset
- case arw.JPEGInterchangeFormatLength:
- jpegLength = meta.FIA[i].Offset
- }
- }
- jpg, err := arw.ExtractThumbnail(fp, jpegOffset, jpegLength)
- if err != nil {
- return nil, err
- }
- reader := bytes.NewReader(jpg)
- img, err = jpeg.Decode(reader)
- if err != nil {
- return nil, err
- }
- } else {
- img, _, err = image.Decode(fp)
- }
-
- if err != nil {
- return nil, err
- }
-
- return img, nil
-}
-
-func hash(img image.Image) (string, error) {
- hasher := ish.NewAverageHash(1024, 1024)
- dh, err := hasher.Hash(img)
- if err != nil {
- return "", err
- }
-
- h := sha256.New()
- h.Write(dh)
-
- return hex.EncodeToString(h.Sum(nil)), nil
-}
-
 func main() {
  flag.Usage = func() {
  fmt.Printf("Usage: %s [OPTION]... [FILE]...\n", os.Args[0])
@@ -230,24 +153,15 @@ func main() {
 
  if *check_mode == true {
  for file := range flag.Args() {
- err := checkFiles(flag.Arg(file))
- if err != nil {
- fmt.Fprintln(os.Stderr, err)
- }
+ check(flag.Arg(file))
  }
  } else if *deduplicate_mode {
  for file := range flag.Args() {
- err := deduplicate(flag.Arg(file), *json_output)
- if err != nil {
- fmt.Fprintln(os.Stderr, err)
- }
+ deduplicate(flag.Arg(file), *json_output)
  }
  } else {
  for file := range flag.Args() {
- err := calculate(flag.Arg(file))
- if err != nil {
- fmt.Fprintln(os.Stderr, err)
- }
+ calculate(flag.Arg(file))
  }
  }
 }

src/imgsum/image/image.go

@@ -0,0 +1,131 @@
+package image
+
+import (
+ "bytes"
+ "crypto/sha256"
+ "encoding/hex"
+ stdimage "image"
+ "image/jpeg"
+ "os"
+ "regexp"
+
+ "github.com/brett-lempereur/ish"
+ "github.com/Soreil/arw"
+ "github.com/nf/cr2"
+)
+
+var (
+ re_canon = regexp.MustCompile("(?i).cr(2)$")
+ re_sony = regexp.MustCompile("(?i).(arw|sr2)$")
+)
+
+type Image struct {
+ filename string
+ fp *os.File
+ image stdimage.Image
+}
+
+func NewImage(filename string) (*Image, error) {
+ i := new(Image)
+ i.filename = filename
+
+ err := i.open()
+ if err != nil {
+ return nil, err
+ }
+ return i, nil
+}
+
+func (i *Image) open() (error) {
+ var err error
+ i.fp, err = os.Open(i.filename)
+ if err != nil {
+ return err
+ }
+ defer i.fp.Close()
+
+ if re_canon.Match([]byte(i.filename)) {
+ err = i.openCanonRaw()
+ } else if re_sony.Match([]byte(i.filename)) {
+ err = i.openSonyRaw()
+ } else {
+ err = i.openStdImage()
+ }
+
+ if err != nil {
+ return err
+ }
+ return nil
+}
+
+func (i *Image) openStdImage() (error) {
+ var err error
+ i.image, _, err = stdimage.Decode(i.fp)
+ if err != nil {
+ return err
+ }
+
+ return nil
+}
+
+func (i *Image) openCanonRaw() (error) {
+ var err error
+ i.image, err = cr2.Decode(i.fp)
+ if err != nil {
+ return err
+ }
+ return nil
+}
+
+func (i *Image) openSonyRaw() (error) {
+ var jpegOffset uint32
+ var jpegLength uint32
+
+ header, err := arw.ParseHeader(i.fp)
+ if err != nil {
+ return err
+ }
+
+ meta, err := arw.ExtractMetaData(i.fp, int64(header.Offset), 0)
+ if err != nil {
+ return err
+ }
+
+ for i := range meta.FIA {
+ switch meta.FIA[i].Tag {
+ case arw.JPEGInterchangeFormat:
+ jpegOffset = meta.FIA[i].Offset
+ case arw.JPEGInterchangeFormatLength:
+ jpegLength = meta.FIA[i].Offset
+ }
+ }
+
+ jpg, err := arw.ExtractThumbnail(i.fp, jpegOffset, jpegLength)
+ if err != nil {
+ return err
+ }
+
+ reader := bytes.NewReader(jpg)
+ i.image, err = jpeg.Decode(reader)
+ if err != nil {
+ return err
+ }
+ return nil
+}
+
+func (i *Image) Hexdigest() (string, error) {
+ hasher := ish.NewAverageHash(1024, 1024)
+ dh, err := hasher.Hash(i.image)
+ if err != nil {
+ return "", err
+ }
+
+ h := sha256.New()
+ h.Write(dh)
+
+ return hex.EncodeToString(h.Sum(nil)), nil
+}
+
+func (i *Image) Filename() (string) {
+ return i.filename
+}