Add a package for backing up files

This can be used for recovery in the event something goes wrong while in the middle of a operation that modified the
production files content.

Author: per1234

internal/backup/backup.go

@@ -0,0 +1,107 @@
+// This file is part of libraries-repository-engine.
+//
+// Copyright 2021 ARDUINO SA (http://www.arduino.cc/)
+//
+// 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, either version 3 of the License, or
+// (at your option) any later version.
+//
+// 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/>.
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to [email protected].
+
+// Package backup does backup and restore of files.
+package backup
+
+import (
+	"github.com/arduino/go-paths-helper"
+)
+
+type backup struct {
+	originalPath *paths.Path
+	backupPath   *paths.Path
+}
+
+var backupsFolder *paths.Path
+var backups []backup
+
+// Backup saves a backup copy of the given path.
+func Backup(originalPath *paths.Path) error {
+	if backupsFolder == nil {
+		// Create a parent folder to store all backups of this session.
+		var err error
+		if backupsFolder, err = paths.MkTempDir("", "libraries-repository-engine-backup"); err != nil {
+			return err
+		}
+	}
+
+	// Create a folder for this individual backup item.
+	backupFolder, err := backupsFolder.MkTempDir("")
+	if err != nil {
+		return err
+	}
+
+	backupPath := backupFolder.Join(originalPath.Base())
+
+	isDir, err := originalPath.IsDirCheck()
+	if err != nil {
+		return err
+	}
+	if isDir {
+		if err := originalPath.CopyDirTo(backupPath); err != nil {
+			return err
+		}
+	} else {
+		if err := originalPath.CopyTo(backupPath); err != nil {
+			return err
+		}
+	}
+
+	backups = append(backups, backup{originalPath: originalPath, backupPath: backupPath})
+
+	return nil
+}
+
+// Restore restores all backed up files.
+func Restore() error {
+	for _, backup := range backups {
+		isDir, err := backup.backupPath.IsDirCheck()
+		if err != nil {
+			return err
+		}
+		if isDir {
+			if err := backup.originalPath.RemoveAll(); err != nil {
+				return err
+			}
+			if err := backup.backupPath.CopyDirTo(backup.originalPath); err != nil {
+				return err
+			}
+		} else {
+			if err := backup.backupPath.CopyTo(backup.originalPath); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+// Clean deletes all the backup files.
+func Clean() error {
+	if backupsFolder == nil {
+		return nil
+	}
+
+	return backupsFolder.RemoveAll()
+}

internal/backup/backup_test.go

@@ -0,0 +1,94 @@
+// This file is part of libraries-repository-engine.
+//
+// Copyright 2021 ARDUINO SA (http://www.arduino.cc/)
+//
+// 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, either version 3 of the License, or
+// (at your option) any later version.
+//
+// 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/>.
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to [email protected].
+
+package backup
+
+import (
+	"testing"
+
+	"github.com/arduino/go-paths-helper"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+var testDataPath string
+
+func TestAll(t *testing.T) {
+	var err error
+	originalsFolder, err := paths.MkTempDir("", "backup-test-testall")
+	require.NoError(t, err)
+
+	// Generate test content.
+	originalContent := []byte("foo")
+	modifyFile, err := paths.WriteToTempFile(originalContent, originalsFolder, "")
+	require.NoError(t, err)
+	modifyFolder, err := originalsFolder.MkTempDir("")
+	require.NoError(t, err)
+	modifyFolderFile, err := paths.WriteToTempFile(originalContent, modifyFolder, "")
+	require.NoError(t, err)
+	deleteFile, err := paths.WriteToTempFile(originalContent, originalsFolder, "")
+	require.NoError(t, err)
+	deleteFolder, err := originalsFolder.MkTempDir("")
+	require.NoError(t, err)
+	deleteFolderFile, err := paths.WriteToTempFile(originalContent, deleteFolder, "")
+	require.NoError(t, err)
+
+	// Backup test content.
+	err = Backup(modifyFile)
+	require.NoError(t, err)
+	err = Backup(modifyFolder)
+	require.NoError(t, err)
+	err = Backup(deleteFile)
+	require.NoError(t, err)
+	err = Backup(deleteFolder)
+	require.NoError(t, err)
+
+	// Change the originals.
+	err = modifyFile.WriteFile([]byte("bar"))
+	require.NoError(t, err)
+	err = modifyFolderFile.WriteFile([]byte("bar"))
+	require.NoError(t, err)
+	err = deleteFile.Remove()
+	require.NoError(t, err)
+	err = deleteFolder.RemoveAll()
+	require.NoError(t, err)
+
+	err = Restore()
+	require.NoError(t, err)
+
+	// Verify changes to originals were reverted.
+	content, err := modifyFile.ReadFile()
+	require.NoError(t, err)
+	assert.Equal(t, originalContent, content)
+
+	content, err = modifyFolderFile.ReadFile()
+	require.NoError(t, err)
+	assert.Equal(t, originalContent, content)
+
+	assert.True(t, deleteFile.Exist())
+	assert.True(t, deleteFolderFile.Exist())
+
+	// Clean the backups.
+	err = Clean()
+	require.NoError(t, err)
+}