Add Symlink, Lstat and ReadLink function for the Driver interface (#229)

driver/driver.go

@@ -17,6 +17,8 @@ type Driver interface {
 	MkdirAll(path string) error
 	// Create creates the named file
 	Create(path string) (err error)
+	// Symlink create a symbolic link
+	Symlink(oldname, newname string) error
 	// Remove removes the specified file or directory
 	Remove(path string) error
 	// Rename renames a file
@@ -27,10 +29,14 @@ type Driver interface {
 	WalkDir(root string, fn fs.WalkDirFunc) error
 	// Open opens the named file for reading
 	Open(path string) (f http.File, err error)
-	// Stat returns the os.FileInfo describing the named file
+	// Stat returns the os.FileInfo describing the named file, if path is a symbolic link, read the real file
 	Stat(path string) (fi os.FileInfo, err error)
+	// Lstat returns the os.FileInfo describing the named file, if path is a symbolic link, read the symbolic link info
+	Lstat(path string) (fi os.FileInfo, err error)
 	// GetFileTime get the creation time, last access time, last modify time of the path
 	GetFileTime(path string) (cTime time.Time, aTime time.Time, mTime time.Time, err error)
 	// Write write src file to dest file
 	Write(src string, dest string) error
+	// ReadLink returns the destination of the named symbolic link
+	ReadLink(path string) (string, error)
 }

driver/minio/minio.go

@@ -18,6 +18,7 @@ import (
 	"github.com/minio/minio-go/v7/pkg/credentials"
 	"github.com/minio/minio-go/v7/pkg/s3utils"
 	"github.com/no-src/gofs/driver"
+	nsfs "github.com/no-src/gofs/fs"
 	"github.com/no-src/gofs/internal/rate"
 	"github.com/no-src/gofs/retry"
 	"github.com/no-src/log"
@@ -144,6 +145,18 @@ func (c *minIODriver) Create(path string) (err error) {
 	return err
 }
 
+func (c *minIODriver) Symlink(oldname, newname string) (err error) {
+	if err = c.Remove(newname); err != nil {
+		return err
+	}
+	err = c.reconnectIfLost(func() error {
+		content := nsfs.SymlinkText(oldname)
+		_, err = c.client.PutObject(c.ctx, c.bucketName, newname, bytes.NewReader([]byte(content)), int64(len(content)), minio.PutObjectOptions{})
+		return err
+	})
+	return err
+}
+
 func (c *minIODriver) Remove(path string) (err error) {
 	return c.reconnectIfLost(func() error {
 		infoChan := c.client.ListObjects(c.ctx, c.bucketName, minio.ListObjectsOptions{
@@ -250,6 +263,10 @@ func (c *minIODriver) Stat(path string) (fi os.FileInfo, err error) {
 	return fi, err
 }
 
+func (c *minIODriver) Lstat(path string) (fi os.FileInfo, err error) {
+	return c.Stat(path)
+}
+
 func (c *minIODriver) GetFileTime(path string) (cTime time.Time, aTime time.Time, mTime time.Time, err error) {
 	err = c.reconnectIfLost(func() error {
 		var info minio.ObjectInfo
@@ -288,6 +305,10 @@ func (c *minIODriver) Client() *minio.Client {
 	return c.client
 }
 
+func (c *minIODriver) ReadLink(path string) (string, error) {
+	return path, nil
+}
+
 // fPutObject - Create an object in a bucket, with contents from file at filePath. Allows request cancellation.
 // Keep up to date with the minio.Client.FPutObject.
 func (c *minIODriver) fPutObject(ctx context.Context, bucketName, objectName, filePath string, opts minio.PutObjectOptions) (info minio.UploadInfo, err error) {

driver/sftp/sftp.go

@@ -172,9 +172,18 @@ func (sc *sftpDriver) Create(path string) (err error) {
 	return err
 }
 
+func (sc *sftpDriver) Symlink(oldname, newname string) error {
+	if err := sc.Remove(newname); err != nil {
+		return err
+	}
+	return sc.reconnectIfLost(func() error {
+		return sc.client.Symlink(oldname, newname)
+	})
+}
+
 func (sc *sftpDriver) Remove(path string) error {
 	return sc.reconnectIfLost(func() error {
-		f, err := sc.client.Stat(path)
+		f, err := sc.client.Lstat(path)
 		if os.IsNotExist(err) {
 			return nil
 		}
@@ -260,10 +269,18 @@ func (sc *sftpDriver) Stat(path string) (fi os.FileInfo, err error) {
 	return fi, err
 }
 
+func (sc *sftpDriver) Lstat(path string) (fi os.FileInfo, err error) {
+	err = sc.reconnectIfLost(func() error {
+		fi, err = sc.client.Lstat(path)
+		return err
+	})
+	return fi, err
+}
+
 func (sc *sftpDriver) GetFileTime(path string) (cTime time.Time, aTime time.Time, mTime time.Time, err error) {
 	err = sc.reconnectIfLost(func() error {
 		var fi os.FileInfo
-		fi, err = sc.client.Stat(path)
+		fi, err = sc.client.Lstat(path)
 		if err != nil {
 			return err
 		}
@@ -315,6 +332,14 @@ func (sc *sftpDriver) Write(src string, dest string) (err error) {
 	return err
 }
 
+func (sc *sftpDriver) ReadLink(path string) (realPath string, err error) {
+	err = sc.reconnectIfLost(func() error {
+		realPath, err = sc.client.ReadLink(path)
+		return err
+	})
+	return realPath, err
+}
+
 type statDirEntry struct {
 	info fs.FileInfo
 }