dircpy

A cross-platform library to recursively copy directories, with some convenience added.

use dircpy::*;

// Most basic example:
copy_dir("src", "dest");

// Simple builder example:
CopyBuilder::new("src", "dest")
  .run()
  .unwrap();

// Copy recursively, only including certain files:
CopyBuilder::new("src", "dest")
  .overwrite_if_newer(true)
  .overwrite_if_size_differs(true)
  .with_include_filter(".txt")
  .with_include_filter(".csv")
  .run()
  .unwrap();

// Copy with progress:
CopyBuilder::new("src", "dest")
  .with_progress(|all, done| {
    println!("copied {done}/{all}");
  })
  .run()
  .unwrap();

// Copy files with up to 4 threads, which is faster for many small files:
CopyBuilder::new("src", "dest")
  .run_par()
  .unwrap();

Performance

run_par walks the source on the calling thread, creating directories and doing all checks, while up to 4 threads copy the files. This is considerably faster for many small files on SSDs. For large files, copying is limited by the disk, and run_par has no advantage. On spinning disks, parallel copying can be slower.

Copying to a new destination, measured with cargo bench on Linux with a Ryzen 7 4800H and an NVMe SSD:

Data	run	run_par	cp -r
10000 files of 2 KiB	348 ms	146 ms	321 ms
500 files of 256 KiB	76 ms	32 ms	76 ms
Source tree: 4525 files of 0.5 to 16 KiB in 780 directories	167 ms	40 ms	156 ms

Copying again with overwrite_if_newer and overwrite_if_size_differs only compares metadata, and takes 48 ms for the 10000 files, with either method.

Run cargo bench to measure on your system. It compares with lms as well, if installed.