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Example to find loops for a given path

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Ty Coghlan 2017-07-13 21:12:00 -04:00 committed by Michał Budzyński
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commit fad366bca4
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50
src/app.md
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@ -6,6 +6,7 @@
| [Decompress a tarball][ex-tar-decompress] | [![flate2-badge]][flate2] [![tar-badge]][tar] | [![cat-compression-badge]][cat-compression] |
| [Compress a directory into a tarball][ex-tar-compress] | [![flate2-badge]][flate2] [![tar-badge]][tar] | [![cat-compression-badge]][cat-compression] |
| [Decompress a tarball while removing a prefix from the paths][ex-tar-strip-prefix] | [![flate2-badge]][flate2] [![tar-badge]][tar] | [![cat-compression-badge]][cat-compression] |
| [Find loops for a given path][ex-find-file-loops] | [![same_file-badge]][same_file] | [![cat-filesystem-badge]][cat-filesystem] |
| [Recursively find duplicate file names][ex-dedup-filenames] | [![walkdir-badge]][walkdir] | [![cat-filesystem-badge]][cat-filesystem] |
| [Recursively find all files with given predicate][ex-file-predicate] | [![walkdir-badge]][walkdir] | [![cat-filesystem-badge]][cat-filesystem] |
| [Traverse directories while skipping dotfiles][ex-file-skip-dot] | [![walkdir-badge]][walkdir] | [![cat-filesystem-badge]][cat-filesystem] |
@ -248,6 +249,52 @@ fn run() -> Result<()> {
# quick_main!(run);
```
[ex-find-file-loops]: #ex-find-file-loops
<a name="ex-find-file-loops"></a>
## Find loops for a given path
[![same_file-badge]][same_file] [![cat-filesystem-badge]][cat-filesystem]
Use [`same_file::is_same_file`] to detect loops for a given path.
For example, a loop could be created on a unix system via sym links:
```
mkdir -p /tmp/foo/bar/baz
ln -s /tmp/foo/ /tmp/foo/bar/baz/qux
```
Then, running the following would assert that there exists a loop.
```rust,no_run
extern crate same_file;
use std::io;
use std::path::{Path, PathBuf};
use same_file::is_same_file;
// Check this path against all of its parents
fn contains_loop<P: AsRef<Path>>(path: P) -> io::Result<Option<(PathBuf, PathBuf)>> {
let path = path.as_ref();
let mut path_buf = path.to_path_buf();
while path_buf.pop() {
if is_same_file(&path_buf, path)? {
return Ok(Some((path_buf, path.to_path_buf())));
} else if let Some(looped_paths) = contains_loop(&path_buf)? {
return Ok(Some(looped_paths));
}
}
return Ok(None);
}
fn main() {
assert_eq!(
contains_loop("/tmp/foo/bar/baz/qux/bar/baz").unwrap(),
Some((
PathBuf::from("/tmp/foo"),
PathBuf::from("/tmp/foo/bar/baz/qux")
))
);
}
```
[ex-dedup-filenames]: #ex-dedup-filenames
<a name="ex-dedup-filenames"></a>
## Recursively find duplicate file names
@ -493,6 +540,8 @@ fn run() -> Result<()> {
[flate2]: https://docs.rs/flate2/
[glob-badge]:https://badge-cache.kominick.com/crates/v/glob.svg?label=glob
[glob]: https://docs.rs/glob/
[same_file-badge]: https://badge-cache.kominick.com/crates/v/same_file.svg?label=same_file
[same_file]: https://docs.rs/same-file/
[tar-badge]: https://badge-cache.kominick.com/crates/v/tar.svg?label=tar
[tar]: https://docs.rs/tar/
[walkdir-badge]: https://badge-cache.kominick.com/crates/v/walkdir.svg?label=walkdir
@ -511,6 +560,7 @@ fn run() -> Result<()> {
[`Iterator::filter`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.filter
[`MatchOptions`]: https://docs.rs/glob/*/glob/struct.MatchOptions.html
[`Path::strip_prefix`]: https://doc.rust-lang.org/std/path/struct.Path.html#method.strip_prefix
[`same_file::is_same_file`]: https://docs.rs/same-file/*/same_file/fn.is_same_file.html#method.is_same_file
[`WalkDir::DirEntry`]: https://docs.rs/walkdir/*/walkdir/struct.DirEntry.html
[`WalkDir::depth`]: https://docs.rs/walkdir/*/walkdir/struct.DirEntry.html#method.depth
[`WalkDir::max_depth`]: https://docs.rs/walkdir/*/walkdir/struct.WalkDir.html#method.max_depth

4
src/intro.md
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@ -79,6 +79,7 @@ community. It needs and welcomes help. For details see
| [Decompress a tarball][ex-tar-decompress] | [![flate2-badge]][flate2] [![tar-badge]][tar] | [![cat-compression-badge]][cat-compression] |
| [Compress a directory into a tarball][ex-tar-compress] | [![flate2-badge]][flate2] [![tar-badge]][tar] | [![cat-compression-badge]][cat-compression] |
| [Decompress a tarball while removing a prefix from the paths][ex-tar-strip-prefix] | [![flate2-badge]][flate2] [![tar-badge]][tar] | [![cat-compression-badge]][cat-compression] |
| [Find loops for a given path][ex-find-file-loops] | [![same_file-badge]][same_file] | [![cat-filesystem-badge]][cat-filesystem] |
| [Recursively find duplicate file names][ex-dedup-filenames] | [![walkdir-badge]][walkdir] | [![cat-filesystem-badge]][cat-filesystem] |
| [Recursively find all files with given predicate][ex-file-predicate] | [![walkdir-badge]][walkdir] | [![cat-filesystem-badge]][cat-filesystem] |
| [Traverse directories while skipping dotfiles][ex-file-skip-dot] | [![walkdir-badge]][walkdir] | [![cat-filesystem-badge]][cat-filesystem] |
@ -187,6 +188,8 @@ Keep lines sorted.
[regex]: https://docs.rs/regex/
[reqwest-badge]: https://badge-cache.kominick.com/crates/v/reqwest.svg?label=reqwest
[reqwest]: https://docs.rs/reqwest/
[same_file-badge]: https://badge-cache.kominick.com/crates/v/same_file.svg?label=same_file
[same_file]: https://docs.rs/same-file/
[select-badge]: https://badge-cache.kominick.com/crates/v/select.svg?label=select
[select]: https://docs.rs/select/
[serde-badge]: https://badge-cache.kominick.com/crates/v/serde.svg?label=serde
@ -224,6 +227,7 @@ Keep lines sorted.
[ex-file-predicate]: app.html#ex-file-predicate
[ex-file-skip-dot]: app.html#ex-file-skip-dot
[ex-file-sizes]: app.html#ex-file-sizes
[ex-find-file-loops]: app.html#ex-find-file-loops
[ex-global-mut-state]: basics.html#ex-global-mut-state
[ex-glob-recursive]: app.html#ex-glob-recursive
[ex-glob-with]: app.html#ex-glob-with