536 lines
20 KiB
Rust
536 lines
20 KiB
Rust
/*! Locale detection and management.
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* Based on https://github.com/rust-locale/locale_config
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*
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* Ready for deletion/replacement once Debian starts packaging this,
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* although this version doesn't need lazy_static.
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*
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* Copyright (c) 2016–2019 Jan Hudec <bulb@ucw.cz>
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Copyright (c) 2016 A.J. Gardner <aaron.j.gardner@gmail.com>
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Copyright (c) 2019, Bastien Orivel <eijebong@bananium.fr>
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Copyright (c) 2019, Igor Gnatenko <i.gnatenko.brain@gmail.com>
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Copyright (c) 2019, Sophie Tauchert <999eagle@999eagle.moe>
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*/
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use regex::Regex;
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use std::borrow::Cow;
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use std::env;
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/// Errors that may be returned by `locale_config`.
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#[derive(Copy,Clone,Debug,PartialEq,Eq)]
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pub enum Error {
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/// Provided definition was not well formed.
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///
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/// This is returned when provided configuration string does not match even the rather loose
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/// definition for language range from [RFC4647] or the composition format used by `Locale`.
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///
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/// [RFC4647]: https://www.rfc-editor.org/rfc/rfc4647.txt
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NotWellFormed,
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/// Placeholder for adding more errors in future. **Do not match!**.
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__NonExhaustive,
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}
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impl ::std::fmt::Display for Error {
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fn fmt(&self, out: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
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out.write_str(match self {
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&Error::NotWellFormed => "Language tag is not well-formed.",
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// this is exception: here we do want exhaustive match so we don't publish version with
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// missing descriptions by mistake.
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&Error::__NonExhaustive => panic!("Placeholder error must not be instantiated!"),
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})
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}
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}
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/// Convenience Result alias.
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type Result<T> = ::std::result::Result<T, Error>;
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/// Iterator over `LanguageRange`s for specific category in a `Locale`
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///
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/// Returns `LanguageRange`s in the `Locale` that are applicable to provided category. The tags
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/// are returned in order of preference, which means the category-specific ones first and then
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/// the generic ones.
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///
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/// The iterator is guaranteed to return at least one value.
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pub struct TagsFor<'a, 'c> {
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src: &'a str,
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tags: std::str::Split<'a, &'static str>,
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category: Option<&'c str>,
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}
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impl<'a, 'c> Iterator for TagsFor<'a, 'c> {
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type Item = LanguageRange<'a>;
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fn next(&mut self) -> Option<Self::Item> {
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if let Some(cat) = self.category {
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while let Some(s) = self.tags.next() {
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if s.starts_with(cat) && s[cat.len()..].starts_with("=") {
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return Some(
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LanguageRange { language: Cow::Borrowed(&s[cat.len()+1..]) });
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}
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}
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self.category = None;
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self.tags = self.src.split(",");
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}
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while let Some(s) = self.tags.next() {
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if s.find('=').is_none() {
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return Some(
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LanguageRange{ language: Cow::Borrowed(s) });
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}
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}
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return None;
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}
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}
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/// Language and culture identifier.
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///
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/// This object holds a [RFC4647] extended language range.
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///
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/// The internal data may be owned or shared from object with lifetime `'a`. The lifetime can be
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/// extended using the `into_static()` method, which internally clones the data as needed.
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///
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/// # Syntax
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///
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/// The range is composed of `-`-separated alphanumeric subtags, possibly replaced by `*`s. It
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/// might be empty.
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///
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/// In agreement with [RFC4647], this object only requires that the tag matches:
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///
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/// ```ebnf
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/// language_tag = (alpha{1,8} | "*")
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/// ("-" (alphanum{1,8} | "*"))*
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/// ```
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///
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/// The exact interpretation is up to the downstream localization provider, but it expected that
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/// it will be matched against a normalized [RFC5646] language tag, which has the structure:
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///
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/// ```ebnf
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/// language_tag = language
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/// ("-" script)?
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/// ("-" region)?
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/// ("-" variant)*
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/// ("-" extension)*
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/// ("-" private)?
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///
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/// language = alpha{2,3} ("-" alpha{3}){0,3}
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///
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/// script = aplha{4}
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///
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/// region = alpha{2}
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/// | digit{3}
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///
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/// variant = alphanum{5,8}
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/// | digit alphanum{3}
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///
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/// extension = [0-9a-wyz] ("-" alphanum{2,8})+
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///
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/// private = "x" ("-" alphanum{1,8})+
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/// ```
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///
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/// * `language` is an [ISO639] 2-letter or, where not defined, 3-letter code. A code for
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/// macro-language might be followed by code of specific dialect.
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/// * `script` is an [ISO15924] 4-letter code.
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/// * `region` is either an [ISO3166] 2-letter code or, for areas other than countries, [UN M.49]
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/// 3-digit numeric code.
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/// * `variant` is a string indicating variant of the language.
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/// * `extension` and `private` define additional options. The private part has same structure as
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/// the Unicode [`-u-` extension][u_ext]. Available options are documented for the facets that
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/// use them.
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///
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/// The values obtained by inspecting the system are normalized according to those rules.
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///
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/// The content will be case-normalized as recommended in [RFC5646] §2.1.1, namely:
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///
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/// * `language` is written in lowercase,
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/// * `script` is written with first capital,
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/// * `country` is written in uppercase and
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/// * all other subtags are written in lowercase.
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///
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/// When detecting system configuration, additional options that may be generated under the
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/// [`-u-` extension][u_ext] currently are:
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///
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/// * `cf` — Currency format (`account` for parenthesized negative values, `standard` for minus
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/// sign).
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/// * `fw` — First day of week (`mon` to `sun`).
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/// * `hc` — Hour cycle (`h12` for 1–12, `h23` for 0–23).
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/// * `ms` — Measurement system (`metric` or `ussystem`).
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/// * `nu` — Numbering system—only decimal systems are currently used.
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/// * `va` — Variant when locale is specified in Unix format and the tag after `@` does not
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/// correspond to any variant defined in [Language subtag registry].
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///
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/// And under the `-x-` extension, following options are defined:
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///
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/// * `df` — Date format:
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///
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/// * `iso`: Short date should be in ISO format of `yyyy-MM-dd`.
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///
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/// For example `-df-iso`.
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///
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/// * `dm` — Decimal separator for monetary:
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///
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/// Followed by one or more Unicode codepoints in hexadecimal. For example `-dm-002d` means to
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/// use comma.
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///
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/// * `ds` — Decimal separator for numbers:
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///
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/// Followed by one or more Unicode codepoints in hexadecimal. For example `-ds-002d` means to
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/// use comma.
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///
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/// * `gm` — Group (thousand) separator for monetary:
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///
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/// Followed by one or more Unicode codepoints in hexadecimal. For example `-dm-00a0` means to
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/// use non-breaking space.
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///
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/// * `gs` — Group (thousand) separator for numbers:
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///
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/// Followed by one or more Unicode codepoints in hexadecimal. For example `-ds-00a0` means to
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/// use non-breaking space.
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///
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/// * `ls` — List separator:
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///
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/// Followed by one or more Unicode codepoints in hexadecimal. For example, `-ds-003b` means to
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/// use a semicolon.
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///
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/// [RFC5646]: https://www.rfc-editor.org/rfc/rfc5646.txt
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/// [RFC4647]: https://www.rfc-editor.org/rfc/rfc4647.txt
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/// [ISO639]: https://en.wikipedia.org/wiki/ISO_639
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/// [ISO15924]: https://en.wikipedia.org/wiki/ISO_15924
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/// [ISO3166]: https://en.wikipedia.org/wiki/ISO_3166
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/// [UN M.49]: https://en.wikipedia.org/wiki/UN_M.49
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/// [u_ext]: http://www.unicode.org/reports/tr35/#u_Extension
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/// [Language subtag registry]: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry
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#[derive(Clone,Debug,Eq,Hash,PartialEq)]
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pub struct LanguageRange<'a> {
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language: Cow<'a, str>
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}
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impl<'a> LanguageRange<'a> {
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/// Return LanguageRange for the invariant locale.
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///
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/// Invariant language is identified simply by empty string.
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pub fn invariant() -> LanguageRange<'static> {
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LanguageRange { language: Cow::Borrowed("") }
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}
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/// Create language tag from Unix/Linux/GNU locale tag.
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///
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/// Unix locale tags have the form
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///
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/// > *language* [ `_` *region* ] [ `.` *encoding* ] [ `@` *variant* ]
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///
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/// The *language* and *region* have the same format as RFC5646. *Encoding* is not relevant
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/// here, since Rust always uses Utf-8. That leaves *variant*, which is unfortunately rather
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/// free-form. So this function will translate known variants to corresponding RFC5646 subtags
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/// and represent anything else with Unicode POSIX variant (`-u-va-`) extension.
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///
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/// Note: This function is public here for benefit of applications that may come across this
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/// kind of tags from other sources than system configuration.
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pub fn from_unix(s: &str) -> Result<LanguageRange<'static>> {
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let unix_tag_regex = Regex::new(r"(?ix) ^
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(?P<language> [[:alpha:]]{2,3} )
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(?: _ (?P<region> [[:alpha:]]{2} | [[:digit:]]{3} ))?
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(?: \. (?P<encoding> [0-9a-zA-Z-]{1,20} ))?
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(?: @ (?P<variant> [[:alnum:]]{1,20} ))?
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$ ").unwrap();
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let unix_invariant_regex = Regex::new(r"(?ix) ^
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(?: c | posix )
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(?: \. (?: [0-9a-zA-Z-]{1,20} ))?
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$ ").unwrap();
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if let Some(caps) = unix_tag_regex.captures(s) {
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let src_variant = caps.name("variant").map(|m| m.as_str()).unwrap_or("").to_ascii_lowercase();
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let mut res = caps.name("language").map(|m| m.as_str()).unwrap().to_ascii_lowercase();
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let region = caps.name("region").map(|m| m.as_str()).unwrap_or("");
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let mut script = "";
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let mut variant = "";
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let mut uvariant = "";
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match src_variant.as_ref() {
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// Variants seen in the wild in GNU LibC (via http://lh.2xlibre.net/) or in Debian
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// GNU/Linux Stretch system. Treatment of things not found in RFC5646 subtag registry
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// (http://www.iana.org/assignments/language-subtag-registry/language-subtag-registry)
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// or CLDR according to notes at https://wiki.openoffice.org/wiki/LocaleMapping.
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// Dialects:
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// aa_ER@saaho - NOTE: Can't be found under that name in RFC5646 subtag registry,
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// but there is language Saho with code ssy, which is likely that thing.
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"saaho" if res == "aa" => res = String::from("ssy"),
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// Scripts:
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// @arabic
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"arabic" => script = "Arab",
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// @cyrillic
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"cyrl" => script = "Cyrl",
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"cyrillic" => script = "Cyrl",
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// @devanagari
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"devanagari" => script = "Deva",
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// @hebrew
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"hebrew" => script = "Hebr",
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// tt@iqtelif
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// Neither RFC5646 subtag registry nor CLDR knows anything about this, but as best
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// as I can tell it is Tatar name for Latin (default is Cyrillic).
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"iqtelif" => script = "Latn",
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// @Latn
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"latn" => script = "Latn",
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// @latin
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"latin" => script = "Latn",
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// en@shaw
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"shaw" => script = "Shaw",
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// Variants:
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// sr@ijekavianlatin
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"ijekavianlatin" => {
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script = "Latn";
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variant = "ijekavsk";
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},
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// sr@ije
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"ije" => variant = "ijekavsk",
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// sr@ijekavian
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"ijekavian" => variant = "ijekavsk",
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// ca@valencia
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"valencia" => variant = "valencia",
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// Currencies:
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// @euro - NOTE: We follow suite of Java and Openoffice and ignore it, because it
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// is default for all locales where it sometimes appears now, and because we use
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// explicit currency in monetary formatting anyway.
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"euro" => {},
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// Collation:
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// gez@abegede - NOTE: This is collation, but CLDR does not have any code for it,
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// so we for the moment leave it fall through as -u-va- instead of -u-co-.
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// Anything else:
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// en@boldquot, en@quot, en@piglatin - just randomish stuff
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// @cjknarrow - beware, it's gonna end up as -u-va-cjknarro due to lenght limit
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s if s.len() <= 8 => uvariant = &*s,
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s => uvariant = &s[0..8], // the subtags are limited to 8 chars, but some are longer
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};
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if script != "" {
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res.push('-');
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res.push_str(script);
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}
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if region != "" {
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res.push('-');
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res.push_str(&*region.to_ascii_uppercase());
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}
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if variant != "" {
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res.push('-');
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res.push_str(variant);
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}
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if uvariant != "" {
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res.push_str("-u-va-");
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res.push_str(uvariant);
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}
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return Ok(LanguageRange {
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language: Cow::Owned(res)
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});
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} else if unix_invariant_regex.is_match(s) {
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return Ok(LanguageRange::invariant())
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} else {
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return Err(Error::NotWellFormed);
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}
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}
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}
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impl<'a> AsRef<str> for LanguageRange<'a> {
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fn as_ref(&self) -> &str {
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self.language.as_ref()
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}
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}
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/// Locale configuration.
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///
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/// Users may accept several languages in some order of preference and may want to use rules from
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/// different culture for some particular aspect of the program behaviour, and operating systems
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/// allow them to specify this (to various extent).
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///
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/// The `Locale` objects represent the user configuration. They contain:
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///
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/// - The primary `LanguageRange`.
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/// - Optional category-specific overrides.
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/// - Optional fallbacks in case data (usually translations) for the primary language are not
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/// available.
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///
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/// The set of categories is open-ended. The `locale` crate uses five well-known categories
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/// `messages`, `numeric`, `time`, `collate` and `monetary`, but some systems define additional
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/// ones (GNU Linux has additionally `paper`, `name`, `address`, `telephone` and `measurement`) and
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/// these are provided in the user default `Locale` and other libraries can use them.
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///
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/// `Locale` is represented by a `,`-separated sequence of tags in `LanguageRange` syntax, where
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/// all except the first one may be preceded by category name and `=` sign.
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///
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/// The first tag indicates the default locale, the tags prefixed by category names indicate
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/// _overrides_ for those categories and the remaining tags indicate fallbacks.
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///
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/// Note that a syntactically valid value of HTTP `Accept-Language` header is a valid `Locale`. Not
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/// the other way around though due to the presence of category selectors.
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// TODO: Interning
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#[derive(Clone,Debug,Eq,Hash,PartialEq)]
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pub struct Locale {
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// TODO: Intern the string for performance reasons
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// XXX: Store pre-split to LanguageTags?
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inner: String,
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}
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impl Locale {
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/// Construct invariant locale.
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///
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/// Invariant locale is represented simply with empty string.
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pub fn invariant() -> Locale {
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Locale::from(LanguageRange::invariant())
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}
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/// Append fallback language tag.
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///
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/// Adds fallback to the end of the list.
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pub fn add(&mut self, tag: &LanguageRange) {
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for i in self.inner.split(',') {
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if i == tag.as_ref() {
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return; // don't add duplicates
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}
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}
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self.inner.push_str(",");
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self.inner.push_str(tag.as_ref());
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}
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/// Append category override.
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///
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/// Appending new override for a category that already has one will not replace the existing
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/// override. This might change in future.
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pub fn add_category(&mut self, category: &str, tag: &LanguageRange) {
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if self.inner.split(',').next().unwrap() == tag.as_ref() {
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return; // don't add useless override equal to the primary tag
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}
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for i in self.inner.split(',') {
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if i.starts_with(category) &&
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i[category.len()..].starts_with("=") &&
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&i[category.len() + 1..] == tag.as_ref() {
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return; // don't add duplicates
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}
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}
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self.inner.push_str(",");
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self.inner.push_str(category);
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self.inner.push_str("=");
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self.inner.push_str(tag.as_ref());
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}
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/// Iterate over `LanguageRange`s in this `Locale` applicable to given category.
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///
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/// Returns `LanguageRange`s in the `Locale` that are applicable to provided category. The tags
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/// are returned in order of preference, which means the category-specific ones first and then
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/// the generic ones.
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///
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/// The iterator is guaranteed to return at least one value.
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pub fn tags_for<'a, 'c>(&'a self, category: &'c str) -> TagsFor<'a, 'c> {
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let mut tags = self.inner.split(",");
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while let Some(s) = tags.clone().next() {
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if s.starts_with(category) && s[category.len()..].starts_with("=") {
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return TagsFor {
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src: self.inner.as_ref(),
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tags: tags,
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category: Some(category),
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};
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}
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tags.next();
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}
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return TagsFor {
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src: self.inner.as_ref(),
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tags: self.inner.split(","),
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category: None,
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};
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}
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}
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/// Locale is specified by a string tag. This is the way to access it.
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// FIXME: Do we want to provide the full string representation? We would have it as single string
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// then.
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impl AsRef<str> for Locale {
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fn as_ref(&self) -> &str {
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self.inner.as_ref()
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}
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}
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impl<'a> From<LanguageRange<'a>> for Locale {
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fn from(t: LanguageRange<'a>) -> Locale {
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Locale {
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inner: t.language.into_owned(),
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}
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}
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}
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fn tag(s: &str) -> Result<LanguageRange> {
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LanguageRange::from_unix(s)
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}
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// TODO: Read /etc/locale.alias
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fn tag_inv(s: &str) -> LanguageRange {
|
||
tag(s).unwrap_or(LanguageRange::invariant())
|
||
}
|
||
|
||
pub fn system_locale() -> Option<Locale> {
|
||
// LC_ALL overrides everything
|
||
if let Ok(all) = env::var("LC_ALL") {
|
||
if let Ok(t) = tag(all.as_ref()) {
|
||
return Some(Locale::from(t));
|
||
}
|
||
}
|
||
// LANG is default
|
||
let mut loc =
|
||
if let Ok(lang) = env::var("LANG") {
|
||
Locale::from(tag_inv(lang.as_ref()))
|
||
} else {
|
||
Locale::invariant()
|
||
};
|
||
// category overrides
|
||
for &(cat, var) in [
|
||
("ctype", "LC_CTYPE"),
|
||
("numeric", "LC_NUMERIC"),
|
||
("time", "LC_TIME"),
|
||
("collate", "LC_COLLATE"),
|
||
("monetary", "LC_MONETARY"),
|
||
("messages", "LC_MESSAGES"),
|
||
("paper", "LC_PAPER"),
|
||
("name", "LC_NAME"),
|
||
("address", "LC_ADDRESS"),
|
||
("telephone", "LC_TELEPHONE"),
|
||
("measurement", "LC_MEASUREMENT"),
|
||
].iter() {
|
||
if let Ok(val) = env::var(var) {
|
||
if let Ok(tag) = tag(val.as_ref())
|
||
{
|
||
loc.add_category(cat, &tag);
|
||
}
|
||
}
|
||
}
|
||
// LANGUAGE defines fallbacks
|
||
if let Ok(langs) = env::var("LANGUAGE") {
|
||
for i in langs.split(':') {
|
||
if i != "" {
|
||
if let Ok(tag) = tag(i) {
|
||
loc.add(&tag);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
if loc.as_ref() != "" {
|
||
return Some(loc);
|
||
} else {
|
||
return None;
|
||
}
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod test {
|
||
use super::LanguageRange;
|
||
|
||
#[test]
|
||
fn unix_tags() {
|
||
assert_eq!("cs-CZ", LanguageRange::from_unix("cs_CZ.UTF-8").unwrap().as_ref());
|
||
assert_eq!("sr-RS-ijekavsk", LanguageRange::from_unix("sr_RS@ijekavian").unwrap().as_ref());
|
||
assert_eq!("sr-Latn-ijekavsk", LanguageRange::from_unix("sr.UTF-8@ijekavianlatin").unwrap().as_ref());
|
||
assert_eq!("en-Arab", LanguageRange::from_unix("en@arabic").unwrap().as_ref());
|
||
assert_eq!("en-Arab", LanguageRange::from_unix("en.UTF-8@arabic").unwrap().as_ref());
|
||
assert_eq!("de-DE", LanguageRange::from_unix("DE_de.UTF-8@euro").unwrap().as_ref());
|
||
assert_eq!("ssy-ER", LanguageRange::from_unix("aa_ER@saaho").unwrap().as_ref());
|
||
assert!(LanguageRange::from_unix("foo_BAR").is_err());
|
||
assert!(LanguageRange::from_unix("en@arabic.UTF-8").is_err());
|
||
assert_eq!("", LanguageRange::from_unix("C").unwrap().as_ref());
|
||
assert_eq!("", LanguageRange::from_unix("C.UTF-8").unwrap().as_ref());
|
||
assert_eq!("", LanguageRange::from_unix("C.ISO-8859-1").unwrap().as_ref());
|
||
assert_eq!("", LanguageRange::from_unix("POSIX").unwrap().as_ref());
|
||
}
|
||
}
|