move SFTPGo package to the internal folder

SFTPGo is a daemon and command line tool, not a library.

The public API are provided by the SDK

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

internal/ftpd/transfer.go

@@ -0,0 +1,151 @@
+// Copyright (C) 2019-2022  Nicola Murino
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published
+// by the Free Software Foundation, version 3.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package ftpd
+
+import (
+	"errors"
+	"io"
+	"sync/atomic"
+
+	"github.com/eikenb/pipeat"
+
+	"github.com/drakkan/sftpgo/v2/internal/common"
+	"github.com/drakkan/sftpgo/v2/internal/vfs"
+)
+
+// transfer contains the transfer details for an upload or a download.
+// It implements the ftpserver.FileTransfer interface to handle files downloads and uploads
+type transfer struct {
+	*common.BaseTransfer
+	writer         io.WriteCloser
+	reader         io.ReadCloser
+	isFinished     bool
+	expectedOffset int64
+}
+
+func newTransfer(baseTransfer *common.BaseTransfer, pipeWriter *vfs.PipeWriter, pipeReader *pipeat.PipeReaderAt,
+	expectedOffset int64) *transfer {
+	var writer io.WriteCloser
+	var reader io.ReadCloser
+	if baseTransfer.File != nil {
+		writer = baseTransfer.File
+		reader = baseTransfer.File
+	} else if pipeWriter != nil {
+		writer = pipeWriter
+	} else if pipeReader != nil {
+		reader = pipeReader
+	}
+	return &transfer{
+		BaseTransfer:   baseTransfer,
+		writer:         writer,
+		reader:         reader,
+		isFinished:     false,
+		expectedOffset: expectedOffset,
+	}
+}
+
+// Read reads the contents to downloads.
+func (t *transfer) Read(p []byte) (n int, err error) {
+	t.Connection.UpdateLastActivity()
+
+	n, err = t.reader.Read(p)
+	atomic.AddInt64(&t.BytesSent, int64(n))
+
+	if err == nil {
+		err = t.CheckRead()
+	}
+	if err != nil && err != io.EOF {
+		t.TransferError(err)
+		return
+	}
+	t.HandleThrottle()
+	return
+}
+
+// Write writes the uploaded contents.
+func (t *transfer) Write(p []byte) (n int, err error) {
+	t.Connection.UpdateLastActivity()
+
+	n, err = t.writer.Write(p)
+	atomic.AddInt64(&t.BytesReceived, int64(n))
+
+	if err == nil {
+		err = t.CheckWrite()
+	}
+	if err != nil {
+		t.TransferError(err)
+		return
+	}
+	t.HandleThrottle()
+	return
+}
+
+// Seek sets the offset to resume an upload or a download
+func (t *transfer) Seek(offset int64, whence int) (int64, error) {
+	t.Connection.UpdateLastActivity()
+	if t.File != nil {
+		ret, err := t.File.Seek(offset, whence)
+		if err != nil {
+			t.TransferError(err)
+		}
+		return ret, err
+	}
+	if t.reader != nil && t.expectedOffset == offset && whence == io.SeekStart {
+		return offset, nil
+	}
+	t.TransferError(errors.New("seek is unsupported for this transfer"))
+	return 0, common.ErrOpUnsupported
+}
+
+// Close it is called when the transfer is completed.
+func (t *transfer) Close() error {
+	if err := t.setFinished(); err != nil {
+		return err
+	}
+	err := t.closeIO()
+	errBaseClose := t.BaseTransfer.Close()
+	if errBaseClose != nil {
+		err = errBaseClose
+	}
+	return t.Connection.GetFsError(t.Fs, err)
+}
+
+func (t *transfer) closeIO() error {
+	var err error
+	if t.File != nil {
+		err = t.File.Close()
+	} else if t.writer != nil {
+		err = t.writer.Close()
+		t.Lock()
+		// we set ErrTransfer here so quota is not updated, in this case the uploads are atomic
+		if err != nil && t.ErrTransfer == nil {
+			t.ErrTransfer = err
+		}
+		t.Unlock()
+	} else if t.reader != nil {
+		err = t.reader.Close()
+	}
+	return err
+}
+
+func (t *transfer) setFinished() error {
+	t.Lock()
+	defer t.Unlock()
+	if t.isFinished {
+		return common.ErrTransferClosed
+	}
+	t.isFinished = true
+	return nil
+}