Crate path_absolutize

Expand description

Path Absolutize

This is a library for extending Path and PathBuf in order to get an absolute path and remove the containing dots.

The difference between absolutize and canonicalize methods is that absolutize does not care about whether the file exists and what the file really is.

Please read the following examples to know the parsing rules.

Examples

There are two methods you can use.

absolutize

Get an absolute path.

The dots in a path will be parsed even if it is already an absolute path (which means the path starts with a MAIN_SEPARATOR on Unix-like systems).

use std::path::Path;

use path_absolutize::*;

let p = Path::new("/path/to/123/456");

assert_eq!("/path/to/123/456", p.absolutize().unwrap().to_str().unwrap());

use std::path::Path;

use path_absolutize::*;

let p = Path::new("/path/to/./123/../456");

assert_eq!("/path/to/456", p.absolutize().unwrap().to_str().unwrap());

If a path starts with a single dot, the dot means your program’s current working directory (CWD).

use std::path::Path;
use std::env;

use path_absolutize::*;

let p = Path::new("./path/to/123/456");

assert_eq!(Path::join(env::current_dir().unwrap().as_path(), Path::new("path/to/123/456")).to_str().unwrap(), p.absolutize().unwrap().to_str().unwrap());

If a path starts with a pair of dots, the dots means the parent of the CWD. If the CWD is root, the parent is still root.

use std::path::Path;
use std::env;

use path_absolutize::*;

let p = Path::new("../path/to/123/456");

let cwd = env::current_dir().unwrap();

let cwd_parent = cwd.parent();

match cwd_parent {
   Some(cwd_parent) => {
       assert_eq!(Path::join(&cwd_parent, Path::new("path/to/123/456")).to_str().unwrap(), p.absolutize().unwrap().to_str().unwrap());
   }
   None => {
       assert_eq!(Path::join(Path::new("/"), Path::new("path/to/123/456")).to_str().unwrap(), p.absolutize().unwrap().to_str().unwrap());
   }
}

A path which does not start with a MAIN_SEPARATOR, Single Dot and Double Dots, will act like having a single dot at the start when absolutize method is used.

use std::path::Path;
use std::env;

use path_absolutize::*;

let p = Path::new("path/to/123/456");

assert_eq!(Path::join(env::current_dir().unwrap().as_path(), Path::new("path/to/123/456")).to_str().unwrap(), p.absolutize().unwrap().to_str().unwrap());

use std::path::Path;
use std::env;

use path_absolutize::*;

let p = Path::new("path/../../to/123/456");

let cwd = env::current_dir().unwrap();

let cwd_parent = cwd.parent();

match cwd_parent {
   Some(cwd_parent) => {
       assert_eq!(Path::join(&cwd_parent, Path::new("to/123/456")).to_str().unwrap(), p.absolutize().unwrap().to_str().unwrap());
   }
   None => {
       assert_eq!(Path::join(Path::new("/"), Path::new("to/123/456")).to_str().unwrap(), p.absolutize().unwrap().to_str().unwrap());
   }
}

Starting from a given current working directory

With the absolutize_from function, you can provide the current working directory that the relative paths should be resolved from.

use std::env;
use std::path::Path;

use path_absolutize::*;

let p = Path::new("../path/to/123/456");
let cwd = env::current_dir().unwrap();

println!("{}", p.absolutize_from(cwd).unwrap().to_str().unwrap());

absolutize_virtually

Get an absolute path only under a specific directory.

The dots in a path will be parsed even if it is already an absolute path (which means the path starts with a MAIN_SEPARATOR on Unix-like systems).

use std::path::Path;

use path_absolutize::*;

let p = Path::new("/path/to/123/456");

assert_eq!("/path/to/123/456", p.absolutize_virtually("/").unwrap().to_str().unwrap());

use std::path::Path;

use path_absolutize::*;

let p = Path::new("/path/to/./123/../456");

assert_eq!("/path/to/456", p.absolutize_virtually("/").unwrap().to_str().unwrap());

Every absolute path should under the virtual root.

use std::path::Path;

use std::io::ErrorKind;

use path_absolutize::*;

let p = Path::new("/path/to/123/456");

assert_eq!(ErrorKind::InvalidInput, p.absolutize_virtually("/virtual/root").unwrap_err().kind());

Every relative path should under the virtual root.

use std::path::Path;

use std::io::ErrorKind;

use path_absolutize::*;

let p = Path::new("./path/to/123/456");

assert_eq!(ErrorKind::InvalidInput, p.absolutize_virtually("/virtual/root").unwrap_err().kind());

use std::path::Path;

use std::io::ErrorKind;

use path_absolutize::*;

let p = Path::new("../path/to/123/456");

assert_eq!(ErrorKind::InvalidInput, p.absolutize_virtually("/virtual/root").unwrap_err().kind());

A path which does not start with a MAIN_SEPARATOR, Single Dot and Double Dots, will be located in the virtual root after the absolutize_virtually method is used.

use std::path::Path;

use path_absolutize::*;

let p = Path::new("path/to/123/456");

assert_eq!("/virtual/root/path/to/123/456", p.absolutize_virtually("/virtual/root").unwrap().to_str().unwrap());

use std::path::Path;

use path_absolutize::*;

let p = Path::new("path/to/../../../../123/456");

assert_eq!("/virtual/root/123/456", p.absolutize_virtually("/virtual/root").unwrap().to_str().unwrap());

By default, the absolutize method and the absolutize_virtually method create a new PathBuf instance of the CWD every time in their operation. The overhead is obvious. Although it allows us to safely change the CWD at runtime by the program itself (e.g. using the std::env::set_current_dir function) or outside controls (e.g. using gdb to call chdir), we don’t need that in most cases.

In order to parse paths with better performance, this crate provides three ways to cache the CWD.

once_cell_cache

Enabling the once_cell_cache feature can let this crate use once_cell to cache the CWD. It’s thread-safe and does not need to modify any code, but once the CWD is cached, it cannot be changed anymore at runtime.

[dependencies.path-absolutize]
version = "*"
features = ["once_cell_cache"]

lazy_static_cache

Enabling the lazy_static_cache feature can let this crate use lazy_static to cache the CWD. It’s thread-safe and does not need to modify any code, but once the CWD is cached, it cannot be changed anymore at runtime.

[dependencies.path-absolutize]
version = "*"
features = ["lazy_static_cache"]

unsafe_cache

Enabling the unsafe_cache feature can let this crate use a mutable static variable to cache the CWD. It allows the program to change the CWD at runtime by the program itself, but it’s not thread-safe.

You need to use the update_cwd function to initialize the CWD first. The function should also be used to update the CWD after the CWD is changed.

[dependencies.path-absolutize]
version = "*"
features = ["unsafe_cache"]

use std::path::Path;

use path_absolutize::*;

unsafe {
    update_cwd();
}

let p = Path::new("./path/to/123/456");

println!("{}", p.absolutize().unwrap().to_str().unwrap());

std::env::set_current_dir("/").unwrap();

unsafe {
    update_cwd();
}

println!("{}", p.absolutize().unwrap().to_str().unwrap());

Benchmark

No-cache

cargo bench

once_cell_cache

cargo bench --features once_cell_cache

lazy_static_cache

cargo bench --features lazy_static_cache

unsafe_cache

cargo bench --features unsafe_cache

Re-exports

pub extern crate path_dedot;

Traits

Absolutize
Let Path and PathBuf have absolutize and absolutize_virtually method.