// Package pathutil provides shared path sanitization utilities for
// user-controlled path components used in filesystem operations.
package pathutil
import "strings"
// SafePathComponent sanitizes a string for safe use as a single path component.
// It strips directory separators, path traversal sequences, null bytes, and
// other characters that are problematic in filenames. The result is safe to
// embed in filepath.Join calls without risk of path traversal.
func SafePathComponent(s string) string {
// Strip null bytes (can truncate paths on some systems)
s = strings.ReplaceAll(s, "\x00", "")
// Replace directory separators and traversal-dangerous characters
replacer := strings.NewReplacer(
"/", "-",
"\\", "-",
":", "-",
"*", "-",
"?", "-",
"\"", "",
"<", "",
">", "",
"|", "-",
" ", "_",
)
s = replacer.Replace(s)
// Strip leading dots to prevent hidden files or ".." traversal remnants
s = strings.TrimLeft(s, ".")
// Collapse any remaining ".." sequences that survived replacement
// (e.g., if input was "..-.." after separator replacement)
for strings.Contains(s, "..") {
s = strings.ReplaceAll(s, "..", "")
}
// Strip leading dashes left over from collapsed patterns
s = strings.TrimLeft(s, "-")
// Limit length to avoid filesystem issues
if len(s) > 50 {
s = s[:50]
}
// If nothing remains, return a safe fallback
if s == "" {
return "_"
}
return s
}
