Add command for modifying library data

Although much of the Library Manager content is based on the contents of the individual library repositories, some is
defined during the library registration, and so a change to this after the time of the registration requires direct
action by a maintainer. This procedure will be facilitated by adding the capability to the engine tool's command line
interface in the form of the new `modify` subcommand.

The initial implementation of this command provides for the modification of the library repository URL:

```
libraries-repository-engine modify --repo-url=NEW_URL LIBRARY_NAME
```

will change the current repository URL of the library name specified via the positional argument (LIBRARY_NAME) to the
new repository URL specified via the `--repo-url` flag (NEW_URL).

Author: per1234

internal/cli/modify.go

@@ -0,0 +1,47 @@
+// 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 license@arduino.cc.
+
+package cli
+
+import (
+	"github.com/arduino/libraries-repository-engine/internal/command/modify"
+	"github.com/spf13/cobra"
+)
+
+// modifyCmd defines the `modify` CLI subcommand.
+var modifyCmd = &cobra.Command{
+	Short:                 "Modify library data",
+	Long:                  "Modify a library's registration data",
+	DisableFlagsInUseLine: true,
+	Use: `modify FLAG... LIBRARY_NAME
+
+Modify the registration data of library name LIBRARY_NAME according to the FLAGs.`,
+	Args: cobra.ExactArgs(1),
+	Run:  modify.Run,
+}
+
+func init() {
+	modifyCmd.Flags().String("repo-url", "", "New library repository URL")
+
+	rootCmd.AddCommand(modifyCmd)
+}

internal/command/modify/modify.go

@@ -0,0 +1,217 @@
+// 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 license@arduino.cc.
+
+// Package modify implements the `modify` CLI subcommand used by the maintainer for modifications to the library registration data.
+package modify
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/arduino/go-paths-helper"
+	"github.com/arduino/libraries-repository-engine/internal/backup"
+	"github.com/arduino/libraries-repository-engine/internal/configuration"
+	"github.com/arduino/libraries-repository-engine/internal/feedback"
+	"github.com/arduino/libraries-repository-engine/internal/libraries"
+	"github.com/arduino/libraries-repository-engine/internal/libraries/archive"
+	"github.com/arduino/libraries-repository-engine/internal/libraries/db"
+	"github.com/arduino/libraries-repository-engine/internal/libraries/metadata"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+)
+
+var config *configuration.Config
+var libraryName string
+var libraryData *db.Library
+var releasesData []*db.Release
+
+// Run executes the command.
+func Run(command *cobra.Command, cliArguments []string) {
+	var err error
+	config = configuration.ReadConf(command.Flags())
+
+	libraryName = cliArguments[0]
+
+	librariesDBPath := paths.New(config.LibrariesDB)
+	exist, err := librariesDBPath.ExistCheck()
+	if err != nil {
+		feedback.Errorf("While checking existence of database file: %s", err)
+		os.Exit(1)
+	}
+	if !exist {
+		feedback.Errorf("Database file not found at %s. Check the LibrariesDB configuration value.", librariesDBPath)
+		os.Exit(1)
+	}
+
+	if err := backup.Backup(librariesDBPath); err != nil {
+		feedback.Errorf("While backing up database: %s", err)
+		os.Exit(1)
+	}
+
+	// Load all the library's data from the DB.
+	librariesDb := db.Init(librariesDBPath.String())
+	if !librariesDb.HasLibrary(libraryName) {
+		feedback.Errorf("Library of name %s not found", libraryName)
+		os.Exit(1)
+	}
+	libraryData, err = librariesDb.FindLibrary(libraryName)
+	if err != nil {
+		panic(err)
+	}
+	releasesData = librariesDb.FindReleasesOfLibrary(libraryData)
+
+	restore, err := modifications(command.Flags())
+	if err != nil {
+		feedback.Error(err)
+		if restore {
+			if err := backup.Restore(); err != nil {
+				feedback.Errorf("While restoring the content from backup: %s", err)
+			}
+			fmt.Println("Original files were restored.")
+		} else {
+			if err := backup.Clean(); err != nil {
+				feedback.Errorf("While cleaning up the backup content: %s", err)
+			}
+		}
+		os.Exit(1)
+	}
+
+	if err := librariesDb.Commit(); err != nil {
+		feedback.Errorf("While saving changes to database: %s", err)
+		if err := backup.Restore(); err != nil {
+			feedback.Errorf("While restoring the content from backup: %s", err)
+		}
+		fmt.Println("Original files were restored.")
+		os.Exit(1)
+	}
+
+	if err := backup.Clean(); err != nil {
+		feedback.Errorf("While cleaning up the backup files: %s", err)
+		os.Exit(1)
+	}
+
+	fmt.Println("Success!")
+}
+
+func modifications(flags *pflag.FlagSet) (bool, error) {
+	didModify := false // Require at least one modification operation was specified by user.
+
+	newRepositoryURL, err := flags.GetString("repo-url")
+	if err != nil {
+		return false, err
+	}
+
+	if newRepositoryURL != "" {
+		if err := modifyRepositoryURL(newRepositoryURL); err != nil {
+			return true, err
+		}
+
+		didModify = true
+	}
+
+	if !didModify {
+		return false, fmt.Errorf("No modification flags provided so nothing happened. See 'libraries-repository-engine modify --help'")
+	}
+
+	return false, nil
+}
+
+func modifyRepositoryURL(newRepositoryURL string) error {
+	if !libraries.RepoURLValid(newRepositoryURL) {
+		return fmt.Errorf("Library URL %s does not have a valid format", newRepositoryURL)
+	}
+
+	if libraryData.Repository == newRepositoryURL {
+		return fmt.Errorf("Library %s already has URL %s", libraryName, newRepositoryURL)
+	}
+
+	oldRepositoryURL := libraryData.Repository
+
+	fmt.Printf("Changing URL of library %s from %s to %s\n", libraryName, oldRepositoryURL, newRepositoryURL)
+
+	// Move the library Git clone to the new path.
+	gitClonePath := func(url string) (*paths.Path, error) {
+		libraryRegistration := libraries.Repo{URL: url}
+		gitCloneSubfolder, err := libraryRegistration.AsFolder()
+		if err != nil {
+			return nil, err
+		}
+
+		return paths.New(config.GitClonesFolder, gitCloneSubfolder), nil
+	}
+	oldGitClonePath, err := gitClonePath(oldRepositoryURL)
+	if err != nil {
+		return err
+	}
+	newGitClonePath, err := gitClonePath(newRepositoryURL)
+	if err != nil {
+		return err
+	}
+	if err := newGitClonePath.Parent().MkdirAll(); err != nil {
+		return fmt.Errorf("While creating new library Git clone path: %w", err)
+	}
+	if err := backup.Backup(oldGitClonePath); err != nil {
+		return fmt.Errorf("While backing up library's Git clone: %w", err)
+	}
+	if err := oldGitClonePath.Rename(newGitClonePath); err != nil {
+		return fmt.Errorf("While moving library's Git clone: %w", err)
+	}
+
+	// Update the library repository URL in the database.
+	libraryData.Repository = newRepositoryURL
+
+	// Update library releases.
+	oldRepositoryObject := libraries.Repository{URL: oldRepositoryURL}
+	newRepositoryObject := libraries.Repository{URL: newRepositoryURL}
+	libraryMetadata := metadata.LibraryMetadata{Name: libraryData.Name}
+	for _, releaseData := range releasesData {
+		libraryMetadata.Version = releaseData.Version.String()
+		oldArchiveObject, err := archive.New(&oldRepositoryObject, &libraryMetadata, config)
+		if err != nil {
+			return err
+		}
+		newArchiveObject, err := archive.New(&newRepositoryObject, &libraryMetadata, config)
+		if err != nil {
+			return err
+		}
+
+		// Move the release archive to the correct path for the new URL (some path components are based on the library repo URL).
+		oldArchiveObjectPath := paths.New(oldArchiveObject.Path)
+		newArchiveObjectPath := paths.New(newArchiveObject.Path)
+		if err := newArchiveObjectPath.Parent().MkdirAll(); err != nil {
+			return fmt.Errorf("While creating new library release archives path: %w", err)
+		}
+		if err := backup.Backup(oldArchiveObjectPath); err != nil {
+			return fmt.Errorf("While backing up library release archive: %w", err)
+		}
+		if err := oldArchiveObjectPath.Rename(newArchiveObjectPath); err != nil {
+			return fmt.Errorf("While moving library release archive: %w", err)
+		}
+
+		// Update the release download URL in the database.
+		releaseData.URL = newArchiveObject.URL
+	}
+
+	return nil
+}