Path Absolutize
====================

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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).

```rust
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());
```

```rust
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).

```rust
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**.

```rust
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.

```rust
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());
```

```rust
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.

```rust
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).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).

```rust
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());
```

```rust
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.

```rust
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.

```rust
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());
```

```rust
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.

```rust
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());
```

```rust
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());
```

## Caching

By default, the `absolutize` method and the `absolutize_virtually` method create a new `PathBuf` instance of the CWD every time they need it 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, the `fixed_workdir` feature can be enabled.

```toml
[dependencies.path-absolutize]
version = "*"
features = ["fixed_workdir"]
```

## Benchmark

#### No-cache

```bash
cargo bench
```

#### fixed_workdir

```bash
cargo bench --features fixed_workdir
```

## Crates.io

https://crates.io/crates/path-absolutize

## Documentation

https://docs.rs/path-absolutize

## License

[MIT](LICENSE)