feat: implement checksum calculation for assets

Author: simulot

internal/assets/asset.go

@@ -1,13 +1,15 @@
 package assets
 
 import (
+	"errors"
 	"fmt"
 	"log/slog"
 	"path"
 	"time"
 
 	"github.com/simulot/immich-go/internal/fshelper"
 	"github.com/simulot/immich-go/internal/fshelper/cachereader"
+	"github.com/simulot/immich-go/internal/fshelper/hash"
 )
 
 /*
@@ -161,3 +163,28 @@ func (a *Asset) MergeTags(t2 []Tag) {
 		}
 	}
 }
+
+// GetChecksum returns the checksum of the asset.
+// If the checksum is already set, it returns it. Otherwise, it computes it.
+// Use this method to get the checksum of an asset.
+func (a *Asset) GetChecksum() (string, error) {
+	if a.Checksum != "" {
+		return a.Checksum, nil
+	}
+	if a.File.FS() == nil {
+		return "", errors.New("no file to compute checksum")
+	}
+
+	f, err := a.File.Open()
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	sha1Hash, err := hash.Base64Encode(hash.GetSHA1Hash(f))
+	if err != nil {
+		return "", err
+	}
+	a.Checksum = sha1Hash
+	return a.Checksum, nil
+}

internal/assets/assetFile.go

@@ -22,11 +22,12 @@ func (a *Asset) OpenFile() (osfs.OSFS, error) {
 		}
 		debugfiles.TrackOpenFile(f, a.File.FullName())
 		// Create a cache reader from the FS.File
-		cr, err := cachereader.NewCacheReader(a.File.FullName(), f)
+		cr, sha1, err := cachereader.NewCacheReader(a.File.FullName(), f)
 		if err != nil {
 			return nil, err
 		}
 		a.cacheReader = cr
+		a.Checksum = sha1
 	}
 	return a.cacheReader.OpenFile()
 }