Initial DDC release

internal/files/move.go

@@ -0,0 +1,101 @@
+package files
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	"ddc/internal/diskspace"
+)
+
+var ErrDestinationExists = errors.New("an item with this name already exists in the destination")
+
+func MoveInto(source, destinationDir string, reservedBytes int64, progress func(int64)) error {
+	name := filepath.Base(source)
+	target := filepath.Join(destinationDir, name)
+	if exists(target) {
+		return fmt.Errorf("%w: %s", ErrDestinationExists, name)
+	}
+
+	size, err := TreeSize(source)
+	if err != nil {
+		return err
+	}
+
+	renameErr := os.Rename(source, target)
+	if renameErr == nil {
+		progress(size)
+		return nil
+	}
+	if !errors.Is(renameErr, syscall.EXDEV) {
+		return renameErr
+	}
+
+	if err := diskspace.EnsureFree(destinationDir, size, reservedBytes); err != nil {
+		return err
+	}
+	if err := copyTree(source, target, progress); err != nil {
+		os.RemoveAll(target)
+		return err
+	}
+	return os.RemoveAll(source)
+}
+
+func copyTree(source, target string, progress func(int64)) error {
+	return filepath.WalkDir(source, func(current string, entry fs.DirEntry, walkErr error) error {
+		if walkErr != nil {
+			return walkErr
+		}
+		relative, err := filepath.Rel(source, current)
+		if err != nil {
+			return err
+		}
+		destination := filepath.Join(target, relative)
+
+		switch {
+		case entry.IsDir():
+			return os.MkdirAll(destination, 0o755)
+		case entry.Type().IsRegular():
+			return copyFile(current, destination, progress)
+		default:
+			return nil
+		}
+	})
+}
+
+func copyFile(source, destination string, progress func(int64)) error {
+	input, err := os.Open(source)
+	if err != nil {
+		return err
+	}
+	defer input.Close()
+
+	output, err := os.OpenFile(destination, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o644)
+	if err != nil {
+		return err
+	}
+
+	_, copyErr := io.Copy(output, &progressReader{reader: input, progress: progress})
+	closeErr := output.Close()
+	if copyErr != nil {
+		return copyErr
+	}
+	return closeErr
+}
+
+type progressReader struct {
+	reader   io.Reader
+	progress func(int64)
+}
+
+func (reader *progressReader) Read(buffer []byte) (int, error) {
+	count, err := reader.reader.Read(buffer)
+	if count > 0 {
+		reader.progress(int64(count))
+	}
+	return count, err
+}