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/vfs/statvfs_fallback.go

@@ -0,0 +1,53 @@
+// 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/>.
+
+//go:build !darwin && !linux && !freebsd
+// +build !darwin,!linux,!freebsd
+
+package vfs
+
+import (
+	"github.com/pkg/sftp"
+	"github.com/shirou/gopsutil/v3/disk"
+)
+
+const bsize = uint64(4096)
+
+func getStatFS(path string) (*sftp.StatVFS, error) {
+	usage, err := disk.Usage(path)
+	if err != nil {
+		return nil, err
+	}
+	// we assume block size = 4096
+	blocks := usage.Total / bsize
+	bfree := usage.Free / bsize
+	files := usage.InodesTotal
+	ffree := usage.InodesFree
+	if files == 0 {
+		// these assumptions are wrong but still better than returning 0
+		files = blocks / 4
+		ffree = bfree / 4
+	}
+	return &sftp.StatVFS{
+		Bsize:   bsize,
+		Frsize:  bsize,
+		Blocks:  blocks,
+		Bfree:   bfree,
+		Bavail:  bfree,
+		Files:   files,
+		Ffree:   ffree,
+		Favail:  ffree,
+		Namemax: 255,
+	}, nil
+}