whichdisk 0.3.0

Cross-platform disk/volume resolver — given a path, tells you which disk it's on, its mount point, and the relative path
Documentation 
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<div align="center">
<h1>whichdisk</h1>
</div>
<div align="center">

Cross-platform disk/volume resolver — given a path, tells you which disk it's on, its mount point, and the relative path

[<img alt="github" src="https://img.shields.io/badge/github-al8n/whichdisk-8da0cb?style=for-the-badge&logo=Github" height="22">][Github-url]
<img alt="LoC" src="https://img.shields.io/endpoint?url=https%3A%2F%2Fgist.githubusercontent.com%2Fal8n%2F327b2a8aef9003246e45c6e47fe63937%2Fraw%2Fwhichdisk" height="22">
[<img alt="Build" src="https://img.shields.io/github/actions/workflow/status/al8n/whichdisk/ci.yml?logo=Github-Actions&style=for-the-badge" height="22">][CI-url]
[<img alt="codecov" src="https://img.shields.io/codecov/c/gh/al8n/whichdisk?style=for-the-badge&token=6R3QFWRWHL&logo=codecov" height="22">][codecov-url]

[<img alt="docs.rs" src="https://img.shields.io/badge/docs.rs-whichdisk-66c2a5?style=for-the-badge&labelColor=555555&logo=data:image/svg+xml;base64,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" height="20">][doc-url]
[<img alt="crates.io" src="https://img.shields.io/crates/v/whichdisk?style=for-the-badge&logo=data:image/svg+xml;base64,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" height="22">][crates-url]
[<img alt="crates.io" src="https://img.shields.io/crates/d/whichdisk?color=critical&logo=data:image/svg+xml;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBzdGFuZGFsb25lPSJubyI/PjwhRE9DVFlQRSBzdmcgUFVCTElDICItLy9XM0MvL0RURCBTVkcgMS4xLy9FTiIgImh0dHA6Ly93d3cudzMub3JnL0dyYXBoaWNzL1NWRy8xLjEvRFREL3N2ZzExLmR0ZCI+PHN2ZyB0PSIxNjQ1MTE3MzMyOTU5IiBjbGFzcz0iaWNvbiIgdmlld0JveD0iMCAwIDEwMjQgMTAyNCIgdmVyc2lvbj0iMS4xIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHAtaWQ9IjM0MjEiIGRhdGEtc3BtLWFuY2hvci1pZD0iYTMxM3guNzc4MTA2OS4wLmkzIiB3aWR0aD0iNDgiIGhlaWdodD0iNDgiIHhtbG5zOnhsaW5rPSJodHRwOi8vd3d3LnczLm9yZy8xOTk5L3hsaW5rIj48ZGVmcz48c3R5bGUgdHlwZT0idGV4dC9jc3MiPjwvc3R5bGU+PC9kZWZzPjxwYXRoIGQ9Ik00NjkuMzEyIDU3MC4yNHYtMjU2aDg1LjM3NnYyNTZoMTI4TDUxMiA3NTYuMjg4IDM0MS4zMTIgNTcwLjI0aDEyOHpNMTAyNCA2NDAuMTI4QzEwMjQgNzgyLjkxMiA5MTkuODcyIDg5NiA3ODcuNjQ4IDg5NmgtNTEyQzEyMy45MDQgODk2IDAgNzYxLjYgMCA1OTcuNTA0IDAgNDUxLjk2OCA5NC42NTYgMzMxLjUyIDIyNi40MzIgMzAyLjk3NiAyODQuMTYgMTk1LjQ1NiAzOTEuODA4IDEyOCA1MTIgMTI4YzE1Mi4zMiAwIDI4Mi4xMTIgMTA4LjQxNiAzMjMuMzkyIDI2MS4xMkM5NDEuODg4IDQxMy40NCAxMDI0IDUxOS4wNCAxMDI0IDY0MC4xOTJ6IG0tMjU5LjItMjA1LjMxMmMtMjQuNDQ4LTEyOS4wMjQtMTI4Ljg5Ni0yMjIuNzItMjUyLjgtMjIyLjcyLTk3LjI4IDAtMTgzLjA0IDU3LjM0NC0yMjQuNjQgMTQ3LjQ1NmwtOS4yOCAyMC4yMjQtMjAuOTI4IDIuOTQ0Yy0xMDMuMzYgMTQuNC0xNzguMzY4IDEwNC4zMi0xNzguMzY4IDIxNC43MiAwIDExNy45NTIgODguODMyIDIxNC40IDE5Ni45MjggMjE0LjRoNTEyYzg4LjMyIDAgMTU3LjUwNC03NS4xMzYgMTU3LjUwNC0xNzEuNzEyIDAtODguMDY0LTY1LjkyLTE2NC45MjgtMTQ0Ljk2LTE3MS43NzZsLTI5LjUwNC0yLjU2LTUuODg4LTMwLjk3NnoiIGZpbGw9IiNmZmZmZmYiIHAtaWQ9IjM0MjIiIGRhdGEtc3BtLWFuY2hvci1pZD0iYTMxM3guNzc4MTA2OS4wLmkwIiBjbGFzcz0iIj48L3BhdGg+PC9zdmc+&style=for-the-badge" height="22">][crates-url]
<img alt="license" src="https://img.shields.io/badge/License-Apache%202.0/MIT-blue.svg?style=for-the-badge&fontColor=white&logoColor=f5c076&logo=data:image/svg+xml;base64,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" height="22">

</div>

## Installation

### As a library

```toml
[dependencies]
whichdisk = "0.3"
```

### As a CLI tool

```bash
cargo install whichdisk --features cli
```

## CLI Usage

### Resolve a path

```bash
# Resolve the current working directory
whichdisk

# Resolve a specific path
whichdisk -p /home/user/documents

# Output as JSON
whichdisk -o json

# Output as YAML
whichdisk -o yaml

# Combine options
whichdisk -p /tmp -o json
```

**Default output:**
```text
device="/dev/disk3s5"
mount_point="/System/Volumes/Data"
relative_path="Users/user/Develop/personal/whichdisk"
```

**JSON output** (`-o json`):
```json
{
  "device": "/dev/disk3s5",
  "mount_point": "/System/Volumes/Data",
  "relative_path": "Users/user/Develop/personal/whichdisk"
}
```

### List mounted volumes

```bash
# List all mounted volumes
whichdisk list

# Shorthand
whichdisk l

# Skip ejectable/removable volumes (show only internal disks)
whichdisk list --skip-ejectable

# Skip non-ejectable volumes (show only removable disks)
whichdisk list --skip-non-ejectable

# Output as JSON
whichdisk list -o json

# Output as YAML
whichdisk list -o yaml
```

**Default output:**
```text
mount_point="/" device="/dev/disk3s1s1"
```

**JSON output** (`list -o json`):
```json
[
  {
    "device": "/dev/disk3s1s1",
    "mount_point": "/",
    "is_ejectable": false
  }
]
```

## Library Usage

### Resolve a path to its disk

```rust,ignore
use whichdisk::resolve;

fn main() -> std::io::Result<()> {
    let info = resolve("/home/user/documents/report.pdf")?;

    println!("Mount point:    {}", info.mount_point().display());
    println!("Device:         {:?}", info.device());
    println!("Relative path:  {}", info.relative_path().display());
    println!("Ejectable:      {}", info.is_ejectable());

    Ok(())
}
```

### Get the root filesystem

```rust,ignore
use whichdisk::root;

fn main() -> std::io::Result<()> {
    let info = root()?;
    println!("Root mount:  {}", info.mount_point().display());
    println!("Root device: {:?}", info.device());
    Ok(())
}
```

### List mounted volumes

```rust,ignore
use whichdisk::{list, list_with, list_ejectable, list_non_ejectable, ListOptions};

fn main() -> std::io::Result<()> {
    // List all real (non-virtual) volumes
    for m in list()? {
        println!("{:?} -> {:?} (ejectable: {})",
            m.device(), m.mount_point(), m.is_ejectable());
    }

    // List only ejectable/removable volumes
    for m in list_ejectable()? {
        println!("Removable: {:?}", m.mount_point());
    }

    // List only non-ejectable volumes
    for m in list_non_ejectable()? {
        println!("Internal: {:?}", m.mount_point());
    }

    // Using ListOptions
    let opts = ListOptions::all().set_ejectable_only(true);
    let removable = list_with(opts)?;

    Ok(())
}
```

## Supported Platforms

| Platform | Resolve backend | List backend | Ejectable detection |
|---|---|---|---|
| macOS, iOS, watchOS, tvOS, visionOS | `statfs` via [`rustix`](https://crates.io/crates/rustix) | `NSFileManager` via [`objc2-foundation`](https://crates.io/crates/objc2-foundation) | `NSURLVolumeIsEjectableKey` / `NSURLVolumeIsRemovableKey` |
| FreeBSD, OpenBSD, DragonFlyBSD | `statfs` via [`rustix`](https://crates.io/crates/rustix) | `getmntinfo` via [`libc`](https://crates.io/crates/libc) | `/dev/da*` or `/dev/cd*` device prefix |
| NetBSD | `statvfs` via [`libc`](https://crates.io/crates/libc) | `getmntinfo` via [`libc`](https://crates.io/crates/libc) | `/dev/sd*` or `/dev/cd*` device prefix |
| Linux | `/proc/self/mountinfo` parsing | `/proc/self/mountinfo` parsing | `/dev/disk/by-id/usb-*` |
| Windows | `GetVolumePathNameW` via [`windows-sys`](https://crates.io/crates/windows-sys) | `FindFirstVolumeW` / `FindNextVolumeW` | `GetDriveTypeW` = `DRIVE_REMOVABLE` |

## Performance

- **Thread-local cache** — repeated lookups for paths on the same device skip the underlying syscall/file read entirely
- **Small-buffer optimization** — mount points and device names (typically < 56 bytes) are stored inline on the stack; longer values use reference-counted `bytes::Bytes` (clone is a pointer copy)
- **SIMD-accelerated scanning** — uses [`memchr`](https://crates.io/crates/memchr) for null-terminator and newline searches in the BSD `statfs` buffers and Linux mountinfo parsing

## MSRV

The minimum supported Rust version is **1.85**.

#### License

`whichdisk` is under the terms of both the MIT license and the
Apache License (Version 2.0).

See [LICENSE-APACHE](LICENSE-APACHE), [LICENSE-MIT](LICENSE-MIT) for details.

Copyright (c) 2026 Al Liu.

[Github-url]: https://github.com/al8n/whichdisk/
[CI-url]: https://github.com/al8n/whichdisk/actions/workflows/ci.yml
[doc-url]: https://docs.rs/whichdisk
[crates-url]: https://crates.io/crates/whichdisk
[codecov-url]: https://app.codecov.io/gh/al8n/whichdisk/