Refactor file deletion (#1954)

* Add file deleter
* Change scene delete code
* Add image/gallery delete code
* Don't remove stash library paths
* Fail silently if file does not exist

pkg/file/delete.go

@@ -0,0 +1,161 @@
+package file
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+
+	"github.com/stashapp/stash/pkg/logger"
+)
+
+const deleteFileSuffix = ".delete"
+
+// RenamerRemover provides access to the Rename and Remove functions.
+type RenamerRemover interface {
+	Rename(oldpath, newpath string) error
+	Remove(name string) error
+	RemoveAll(path string) error
+	Stat(name string) (fs.FileInfo, error)
+}
+
+type renamerRemoverImpl struct {
+	RenameFn    func(oldpath, newpath string) error
+	RemoveFn    func(name string) error
+	RemoveAllFn func(path string) error
+	StatFn      func(path string) (fs.FileInfo, error)
+}
+
+func (r renamerRemoverImpl) Rename(oldpath, newpath string) error {
+	return r.RenameFn(oldpath, newpath)
+}
+
+func (r renamerRemoverImpl) Remove(name string) error {
+	return r.RemoveFn(name)
+}
+
+func (r renamerRemoverImpl) RemoveAll(path string) error {
+	return r.RemoveAllFn(path)
+}
+
+func (r renamerRemoverImpl) Stat(path string) (fs.FileInfo, error) {
+	return r.StatFn(path)
+}
+
+// Deleter is used to safely delete files and directories from the filesystem.
+// During a transaction, files and directories are marked for deletion using
+// the Files and Dirs methods. This will rename the files/directories to be
+// deleted. If the transaction is rolled back, then the files/directories can
+// be restored to their original state with the Abort method. If the
+// transaction is committed, the marked files are then deleted from the
+// filesystem using the Complete method.
+type Deleter struct {
+	RenamerRemover RenamerRemover
+	files          []string
+	dirs           []string
+}
+
+func NewDeleter() *Deleter {
+	return &Deleter{
+		RenamerRemover: renamerRemoverImpl{
+			RenameFn:    os.Rename,
+			RemoveFn:    os.Remove,
+			RemoveAllFn: os.RemoveAll,
+			StatFn:      os.Stat,
+		},
+	}
+}
+
+// Files designates files to be deleted. Each file marked will be renamed to add
+// a `.delete` suffix. An error is returned if a file could not be renamed.
+// Note that if an error is returned, then some files may be left renamed.
+// Abort should be called to restore marked files if this function returns an
+// error.
+func (d *Deleter) Files(paths []string) error {
+	for _, p := range paths {
+		// fail silently if the file does not exist
+		if _, err := d.RenamerRemover.Stat(p); err != nil {
+			if errors.Is(err, fs.ErrNotExist) {
+				logger.Warnf("File %q does not exist and therefore cannot be deleted. Ignoring.", p)
+				continue
+			}
+
+			return fmt.Errorf("check file %q exists: %w", p, err)
+		}
+
+		if err := d.renameForDelete(p); err != nil {
+			return fmt.Errorf("marking file %q for deletion: %w", p, err)
+		}
+		d.files = append(d.files, p)
+	}
+
+	return nil
+}
+
+// Dirs designates directories to be deleted. Each directory marked will be renamed to add
+// a `.delete` suffix. An error is returned if a directory could not be renamed.
+// Note that if an error is returned, then some directories may be left renamed.
+// Abort should be called to restore marked files/directories if this function returns an
+// error.
+func (d *Deleter) Dirs(paths []string) error {
+	for _, p := range paths {
+		// fail silently if the file does not exist
+		if _, err := d.RenamerRemover.Stat(p); err != nil {
+			if errors.Is(err, fs.ErrNotExist) {
+				logger.Warnf("Directory %q does not exist and therefore cannot be deleted. Ignoring.", p)
+				continue
+			}
+
+			return fmt.Errorf("check directory %q exists: %w", p, err)
+		}
+
+		if err := d.renameForDelete(p); err != nil {
+			return fmt.Errorf("marking directory %q for deletion: %w", p, err)
+		}
+		d.dirs = append(d.dirs, p)
+	}
+
+	return nil
+}
+
+// Rollback tries to rename all marked files and directories back to their
+// original names and clears the marked list. Any errors encountered are
+// logged. All files will be attempted regardless of any errors occurred.
+func (d *Deleter) Rollback() {
+	for _, f := range append(d.files, d.dirs...) {
+		if err := d.renameForRestore(f); err != nil {
+			logger.Warnf("Error restoring %q: %v", f, err)
+		}
+	}
+
+	d.files = nil
+	d.dirs = nil
+}
+
+// Commit deletes all files marked for deletion and clears the marked list.
+// Any errors encountered are logged. All files will be attempted, regardless
+// of the errors encountered.
+func (d *Deleter) Commit() {
+	for _, f := range d.files {
+		if err := d.RenamerRemover.Remove(f + deleteFileSuffix); err != nil {
+			logger.Warnf("Error deleting file %q: %v", f+deleteFileSuffix, err)
+		}
+	}
+
+	for _, f := range d.dirs {
+		if err := d.RenamerRemover.RemoveAll(f + deleteFileSuffix); err != nil {
+			logger.Warnf("Error deleting directory %q: %v", f+deleteFileSuffix, err)
+		}
+	}
+
+	d.files = nil
+	d.dirs = nil
+}
+
+func (d *Deleter) renameForDelete(path string) error {
+	return d.RenamerRemover.Rename(path, path+deleteFileSuffix)
+}
+
+func (d *Deleter) renameForRestore(path string) error {
+	return d.RenamerRemover.Rename(path+deleteFileSuffix, path)
+}