feat(source link): create perm source link with shorter url

models/file.go

@@ -4,6 +4,7 @@ import (
 	"encoding/gob"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"path"
 	"time"
 
@@ -339,6 +340,25 @@ func (file *File) CanCopy() bool {
 	return file.UploadSessionID == nil
 }
 
+// CreateOrGetSourceLink creates a SourceLink model. If the given model exists, the existing
+// model will be returned.
+func (file *File) CreateOrGetSourceLink() (*SourceLink, error) {
+	res := &SourceLink{}
+	err := DB.Set("gorm:auto_preload", true).Where("file_id = ?", file.ID).Find(&res).Error
+	if err == nil && res.ID > 0 {
+		return res, nil
+	}
+
+	res.FileID = file.ID
+	res.Name = file.Name
+	if err := DB.Save(res).Error; err != nil {
+		return nil, fmt.Errorf("failed to insert SourceLink: %w", err)
+	}
+
+	res.File = *file
+	return res, nil
+}
+
 /*
 	实现 webdav.FileInfo 接口
 */