gecko-dev/third_party/rust/dirs

dirs

Introduction

• a tiny low-level library with a minimal API
• that provides the platform-specific, user-accessible locations
• for retrieving and storing configuration, cache and other data
• on Linux, Redox, Windows (≥ Vista), macOS and other platforms.

The library provides the location of these directories by leveraging the mechanisms defined by

• the XDG base directory and the XDG user directory specifications on Linux and Redox
• the Known Folder API on Windows
• the Standard Directories guidelines on macOS

Platforms

This library is written in Rust, and supports Linux, Redox, macOS and Windows. Other platforms are also supported; they use the Linux conventions.

The minimal required version of Rust is 1.13 except for Redox, where the minimum Rust version depends on the redox_users crate.

It's mid-level sister library, directories, is available for Rust (directories-rs) and on the JVM (directories-jvm).

Usage

Dependency

Add the library as a dependency to your project by inserting

dirs = "4.0"

into the [dependencies] section of your Cargo.toml file.

If you are upgrading from version 2, please read the section on breaking changes first.

Example

Library run by user Alice:

extern crate dirs;

dirs::home_dir();
// Lin: Some(/home/alice)
// Win: Some(C:\Users\Alice)
// Mac: Some(/Users/Alice)

dirs::audio_dir();
// Lin: Some(/home/alice/Music)
// Win: Some(C:\Users\Alice\Music)
// Mac: Some(/Users/Alice/Music)

dirs::config_dir();
// Lin: Some(/home/alice/.config)
// Win: Some(C:\Users\Alice\AppData\Roaming)
// Mac: Some(/Users/Alice/Library/Application Support)

dirs::executable_dir();
// Lin: Some(/home/alice/.local/bin)
// Win: None
// Mac: None

Design Goals

• The dirs library is a low-level crate designed to provide the paths to standard directories as defined by operating systems rules or conventions.
  If your requirements are more complex, e. g. computing cache, config, etc. paths for specific applications or projects, consider using directories instead.
• This library does not create directories or check for their existence. The library only provides information on what the path to a certain directory should be.
  How this information is used is a decision that developers need to make based on the requirements of each individual application.
• This library is intentionally focused on providing information on user-writable directories only, as there is no discernible benefit in returning a path that points to a user-level, writable directory on one operating system, but a system-level, read-only directory on another.
  The confusion and unexpected failure modes of such an approach would be immense.
  • executable_dir is specified to provide the path to a user-writable directory for binaries.
    As such a directory only commonly exists on Linux, it returns None on macOS and Windows.
  • font_dir is specified to provide the path to a user-writable directory for fonts.
    As such a directory only exists on Linux and macOS, it returns None on Windows.
  • runtime_dir is specified to provide the path to a directory for non-essential runtime data. It is required that this directory is created when the user logs in, is only accessible by the user itself, is deleted when the user logs out, and supports all filesystem features of the operating system.
    As such a directory only commonly exists on Linux, it returns None on macOS and Windows.

Features

If you want to compute the location of cache, config or data directories for your own application or project, use ProjectDirs of the directories project instead.

Function name	Value on Linux/Redox	Value on Windows	Value on macOS
home_dir	Some($HOME)	Some({FOLDERID_Profile})	Some($HOME)
cache_dir	Some($XDG_CACHE_HOME) or Some($HOME/.cache)	Some({FOLDERID_LocalAppData})	Some($HOME/Library/Caches)
config_dir	Some($XDG_CONFIG_HOME) or Some($HOME/.config)	Some({FOLDERID_RoamingAppData})	Some($HOME/Library/Application Support)
data_dir	Some($XDG_DATA_HOME) or Some($HOME/.local/share)	Some({FOLDERID_RoamingAppData})	Some($HOME/Library/Application Support)
data_local_dir	Some($XDG_DATA_HOME) or Some($HOME/.local/share)	Some({FOLDERID_LocalAppData})	Some($HOME/Library/Application Support)
executable_dir	Some($XDG_BIN_HOME) or Some($HOME/.local/bin)	None	None
preference_dir	Some($XDG_CONFIG_HOME) or Some($HOME/.config)	Some({FOLDERID_RoamingAppData})	Some($HOME/Library/Preferences)
runtime_dir	Some($XDG_RUNTIME_DIR) or None	None	None
state_dir	Some($XDG_STATE_HOME) or Some($HOME/.local/state)	None	None
audio_dir	Some(XDG_MUSIC_DIR) or None	Some({FOLDERID_Music})	Some($HOME/Music/)
desktop_dir	Some(XDG_DESKTOP_DIR) or None	Some({FOLDERID_Desktop})	Some($HOME/Desktop/)
document_dir	Some(XDG_DOCUMENTS_DIR) or None	Some({FOLDERID_Documents})	Some($HOME/Documents/)
download_dir	Some(XDG_DOWNLOAD_DIR) or None	Some({FOLDERID_Downloads})	Some($HOME/Downloads/)
font_dir	Some($XDG_DATA_HOME/fonts/) or Some($HOME/.local/share/fonts/)	None	Some($HOME/Library/Fonts/)
picture_dir	Some(XDG_PICTURES_DIR) or None	Some({FOLDERID_Pictures})	Some($HOME/Pictures/)
public_dir	Some(XDG_PUBLICSHARE_DIR) or None	Some({FOLDERID_Public})	Some($HOME/Public/)
template_dir	Some(XDG_TEMPLATES_DIR) or None	Some({FOLDERID_Templates})	None
video_dir	Some(XDG_VIDEOS_DIR) or None	Some({FOLDERID_Videos})	Some($HOME/Movies/)

Comparison

There are other crates in the Rust ecosystem that try similar or related things. Here is an overview of them, combined with ratings on properties that guided the design of this crate.

Please take this table with a grain of salt: a different crate might very well be more suitable for your specific use case. (Of course my crate achieves my design goals better than other crates, which might have had different design goals.)

Library	Status	Lin	Mac	Win	Base	User	Proj	Conv
app_dirs	Unmaintained	✔	✔	✔	🞈	✖	✔	✖
app_dirs2	Maintained	✔	✔	✔	🞈	✖	✔	✖
dirs	Developed	✔	✔	✔	✔	✔	✖	✔
directories	Developed	✔	✔	✔	✔	✔	✔	✔
s_app_dir	Unmaintained?	✔	✖	🞈	✖	✖	🞈	✖
standard_paths	Maintained	✔	✖	✔	✔	✔	✔	✖
xdg	Maintained	✔	✖	✖	✔	✖	✔	🞈
xdg-basedir	Unmaintained?	✔	✖	✖	✔	✖	✖	🞈
xdg-rs	Obsolete	✔	✖	✖	✔	✖	✖	🞈

• Lin: Linux support
• Mac: macOS support
• Win: Windows support
• Base: Supports generic base directories
• User: Supports user directories
• Proj: Supports project-specific base directories
• Conv: Follows naming conventions of the operating system it runs on

Build

It's possible to cross-compile this library if the necessary toolchains are installed with rustup. This is helpful to ensure a change hasn't broken code on a different platform.

The following commands will build this library on Linux, macOS and Windows:

cargo build --target=x86_64-unknown-linux-gnu
cargo build --target=x86_64-pc-windows-gnu
cargo build --target=x86_64-apple-darwin
cargo build --target=x86_64-unknown-redox

Changelog

4

• BREAKING CHANGE The behavior of executable_dir has been adjusted to not depend on $XDG_DATA_HOME. Code, which assumed that setting the $XDG_DATA_HOME environment variable also impacted executable_dir if the $XDG_BIN_HOME environment variable was not set, requires adjustment.
• Add support for XDG_STATE_HOME.

3

• BREAKING CHANGE The behavior of config_dir on macOS has been adjusted (thanks to everyone involved):
  • The existing config_dir function has been changed to return the Application Support directory on macOS, as suggested by Apple documentation.
  • The behavior of the config_dir function on non-macOS platforms has not been changed.
  • If you have used the config_dir function to store files, it may be necessary to write code that migrates the files to the new location on macOS.
    (Alternative: change uses of the config_dir function to uses of the preference_dir function to retain the old behavior.)
• The newly added preference_dir function returns the Preferences directory on macOS now, which – according to Apple documentation – shall only be used to store .plist files using Apple-proprietary APIs. – preference_dir and config_dir behave identical on non-macOS platforms.

2

BREAKING CHANGE The behavior of deactivated, missing or invalid XDG User Dirs entries on Linux has been improved (contributed by @tmiasko, thank you!):

• Version 1 returned the user's home directory (Some($HOME)) for such faulty entries, except for a faulty XDG_DESKTOP_DIR entry which returned (Some($HOME/Desktop)).
• Version 2 returns None for such entries.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.