Initial vcom TUI prototype

internal/fs/ops.go

@@ -0,0 +1,183 @@
+package vfs
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+func CopyPath(srcPath string, dstDir string, overwrite bool) (string, error) {
+	srcInfo, err := os.Lstat(srcPath)
+	if err != nil {
+		return "", fmt.Errorf("stat %s: %w", srcPath, err)
+	}
+
+	targetPath := filepath.Join(dstDir, filepath.Base(srcPath))
+	if same, err := samePath(srcPath, targetPath); err != nil {
+		return "", err
+	} else if same {
+		return "", fmt.Errorf("source and target are the same: %s", targetPath)
+	}
+
+	if exists, err := PathExists(targetPath); err != nil {
+		return "", err
+	} else if exists {
+		if !overwrite {
+			return "", ErrOverwrite(targetPath)
+		}
+		if err := os.RemoveAll(targetPath); err != nil {
+			return "", err
+		}
+	}
+
+	if srcInfo.Mode()&os.ModeSymlink != 0 {
+		target, err := os.Readlink(srcPath)
+		if err != nil {
+			return "", err
+		}
+		return targetPath, os.Symlink(target, targetPath)
+	}
+
+	if srcInfo.IsDir() {
+		return targetPath, copyDir(srcPath, targetPath)
+	}
+
+	return targetPath, copyFile(srcPath, targetPath, srcInfo.Mode())
+}
+
+func MovePath(srcPath string, dstDir string, overwrite bool) (string, error) {
+	targetPath := filepath.Join(dstDir, filepath.Base(srcPath))
+	if same, err := samePath(srcPath, targetPath); err != nil {
+		return "", err
+	} else if same {
+		return "", fmt.Errorf("source and target are the same: %s", targetPath)
+	}
+
+	if exists, err := PathExists(targetPath); err != nil {
+		return "", err
+	} else if exists {
+		if !overwrite {
+			return "", ErrOverwrite(targetPath)
+		}
+		if err := os.RemoveAll(targetPath); err != nil {
+			return "", err
+		}
+	}
+
+	if err := os.Rename(srcPath, targetPath); err == nil {
+		return targetPath, nil
+	} else if !errors.Is(err, syscall.EXDEV) {
+		return "", err
+	}
+
+	targetPath, err := CopyPath(srcPath, dstDir, overwrite)
+	if err != nil {
+		return "", err
+	}
+	if err := DeletePath(srcPath); err != nil {
+		return "", err
+	}
+	return targetPath, nil
+}
+
+func PathExists(path string) (bool, error) {
+	if _, err := os.Lstat(path); err == nil {
+		return true, nil
+	} else if errors.Is(err, os.ErrNotExist) {
+		return false, nil
+	} else {
+		return false, err
+	}
+}
+
+func DeletePath(path string) error {
+	return os.RemoveAll(path)
+}
+
+func MakeDir(parent string, name string) (string, error) {
+	target := filepath.Join(parent, name)
+	if err := os.MkdirAll(target, 0o755); err != nil {
+		return "", err
+	}
+	return target, nil
+}
+
+func copyDir(srcDir string, dstDir string) error {
+	info, err := os.Lstat(srcDir)
+	if err != nil {
+		return err
+	}
+	if err := os.MkdirAll(dstDir, info.Mode().Perm()); err != nil {
+		return err
+	}
+
+	entries, err := os.ReadDir(srcDir)
+	if err != nil {
+		return err
+	}
+
+	for _, entry := range entries {
+		srcPath := filepath.Join(srcDir, entry.Name())
+		dstPath := filepath.Join(dstDir, entry.Name())
+
+		info, err := os.Lstat(srcPath)
+		if err != nil {
+			return err
+		}
+
+		switch {
+		case info.Mode()&os.ModeSymlink != 0:
+			target, err := os.Readlink(srcPath)
+			if err != nil {
+				return err
+			}
+			if err := os.Symlink(target, dstPath); err != nil {
+				return err
+			}
+		case info.IsDir():
+			if err := copyDir(srcPath, dstPath); err != nil {
+				return err
+			}
+		default:
+			if err := copyFile(srcPath, dstPath, info.Mode()); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func copyFile(srcPath string, dstPath string, mode os.FileMode) error {
+	srcFile, err := os.Open(srcPath)
+	if err != nil {
+		return err
+	}
+	defer srcFile.Close()
+
+	dstFile, err := os.OpenFile(dstPath, os.O_CREATE|os.O_EXCL|os.O_WRONLY, mode.Perm())
+	if err != nil {
+		return err
+	}
+	defer dstFile.Close()
+
+	if _, err := io.Copy(dstFile, srcFile); err != nil {
+		return err
+	}
+	return nil
+}
+
+func samePath(left string, right string) (bool, error) {
+	leftAbs, err := filepath.Abs(left)
+	if err != nil {
+		return false, err
+	}
+	rightAbs, err := filepath.Abs(right)
+	if err != nil {
+		return false, err
+	}
+	return leftAbs == rightAbs, nil
+}