fs_utils/
copy.rs

1//! Functions to copy files and directories from one place to another.
2use quick_error::ResultExt;
3use std::{
4    fs, io,
5    path::{Path, PathBuf},
6};
7
8struct SourceDirectory<'a>(&'a Path);
9
10struct ObtainEntryIn<'a>(&'a Path);
11
12struct CreateDirectory<'a>(&'a Path);
13
14quick_error! {
15    #[derive(Debug)]
16    pub enum Error {
17        CreateDirectory(p: PathBuf, err: io::Error) {
18            description("A directory could not be created")
19            display("Failed to create directory '{}'", p.display())
20            context(p: CreateDirectory<'a>, err: io::Error) -> (p.0.to_path_buf(), err)
21            cause(err)
22        }
23        ObtainEntry(p: PathBuf, err: io::Error) {
24            description("A directory entry could not be obtained")
25            display("Failed to read directory entry of '{}'", p.display())
26            context(p: ObtainEntryIn<'a>, err: io::Error) -> (p.0.to_path_buf(), err)
27            cause(err)
28        }
29        ReadDirectory(p: PathBuf, err: io::Error) {
30            description("A directory could not be read to obtain its entries")
31            display("Failed to read directory '{}'", p.display())
32            context(p: SourceDirectory<'a>, err: io::Error) -> (p.0.to_path_buf(), err)
33            cause(err)
34        }
35        DestinationDirectoryExists(p: PathBuf) {
36            description("Cannot copy directories into an existing destination directory")
37            display("Destination directory '{}' did already exist", p.display())
38        }
39        Copy(src: PathBuf, dest: PathBuf, err: io::Error) {
40            description("A file could not be copied to its destination")
41            display("Failed to copy '{}' to '{}'", src.display(), dest.display())
42            context(c: (&'a PathBuf, &'a PathBuf), err: io::Error) -> (c.0.clone(), c.1.clone(), err)
43            cause(err)
44        }
45    }
46}
47
48/// Return the computed destination directory, given a source directory.
49pub fn destination_directory(
50    source_dir: impl AsRef<Path>,
51    destination_dir: impl AsRef<Path>,
52) -> PathBuf {
53    let source_dir = source_dir
54        .as_ref()
55        .canonicalize()
56        .unwrap_or_else(|_| source_dir.as_ref().to_path_buf());
57    destination_dir
58        .as_ref()
59        .join(source_dir.file_name().unwrap_or_else(|| "ROOT".as_ref()))
60}
61
62/// Copies the contents of the source directory to the given destination directory.
63/// In `destination_dir`, a new subdirectory with the basename of the `source_dir` will be created.
64/// It will not perform the copy operation if the effective destination directory does already exist.
65///
66/// The returned value will contain a copied directory's path.
67pub fn copy_directory(
68    source_dir: impl AsRef<Path>,
69    destination_dir: impl AsRef<Path>,
70) -> Result<PathBuf, Error> {
71    let dest = destination_directory(source_dir.as_ref(), destination_dir);
72    if dest.is_dir() {
73        return Err(Error::DestinationDirectoryExists(dest));
74    }
75
76    // one possible implementation of walking a directory only visiting files
77    fn visit_dirs(dir: &Path, dest: &Path) -> Result<(), Error> {
78        for entry in fs::read_dir(dir).context(SourceDirectory(dir))? {
79            let path = entry.context(ObtainEntryIn(dir))?.path();
80            if path.is_dir() {
81                visit_dirs(
82                    &path,
83                    &dest.join(path.file_name().expect("should always have filename here")),
84                )?;
85            } else {
86                fs::create_dir_all(&dest).context(CreateDirectory(&dest))?;
87                let dest = dest.join(&path.file_name().expect("should have filename here"));
88                fs::copy(&path, &dest).context((&path, &dest))?;
89            }
90        }
91        Ok(())
92    }
93    visit_dirs(source_dir.as_ref(), &dest)?;
94    Ok(dest)
95}
fs_utils/copy.rs

fs_utils/
copy.rs
