Maraiah/maraiah/file.rs

//! File utilities.

use crate::err::*;
use std::fs;
use std::io::{SeekFrom, prelude::*};

/// Confirms that the path `p` is a folder.
pub fn validate_folder_path(p: &str) -> ResultS<()>
{
   let at = fs::metadata(p)?;
   if at.is_dir() {
      Ok(())
   } else {
      Err(err_msg("not a directory"))
   }
}

impl<T> Drop for SeekBackToStart<T>
   where T: Seek
{
   fn drop(&mut self) {if self.fl {let _ = self.seek(SeekFrom::Start(0));}}
}

impl<T> std::ops::Deref for SeekBackToStart<T>
   where T: Seek
{
   type Target = T;

   fn deref(&self) -> &Self::Target {&self.sc}
}

impl<T> std::ops::DerefMut for SeekBackToStart<T>
   where T: Seek
{
   fn deref_mut(&mut self) -> &mut Self::Target {&mut self.sc}
}

impl<T> SeekBackToStart<T>
   where T: Seek
{
   /// Creates a new `SeekBackToStart` object.
   pub fn new(sc: T) -> Self {Self{sc, fl: true}}

   /// Sets the seek-back flag.
   pub fn set_seek(&mut self, fl: bool) {self.fl = fl;}

   /// Returns the seek-back flag.
   pub fn get_seek(&self) -> bool {self.fl}
}

/// Seeks back to the starting position of the inner object when losing scope,
/// unless a flag is set.
pub struct SeekBackToStart<T: Seek> {
   sc: T,
   fl: bool,
}

// EOF