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use alloc::{string::String, vec};
use core::convert::TryFrom;
fn get_property(name: &'static [u8]) -> Option<String> {
let mut value = vec![0u8; libc::PROP_VALUE_MAX as usize];
// SAFETY: `name` is valid to read from and `value` is valid to write to.
let len =
unsafe { libc::__system_property_get(name.as_ptr().cast(), value.as_mut_ptr().cast()) };
usize::try_from(len)
.ok()
.filter(|n| *n != 0)
.and_then(move |n| {
// Remove excess bytes and the NUL terminator
value.resize(n, 0);
String::from_utf8(value).ok()
})
}
const LOCALE_KEY: &[u8] = b"persist.sys.locale\0";
const PRODUCT_LOCALE_KEY: &[u8] = b"ro.product.locale\0";
const PRODUCT_LANGUAGE_KEY: &[u8] = b"ro.product.locale.language\0";
const PRODUCT_REGION_KEY: &[u8] = b"ro.product.locale.region\0";
// Android 4.0 and below
const LANG_KEY: &[u8] = b"persist.sys.language\0";
const COUNTRY_KEY: &[u8] = b"persist.sys.country\0";
const LOCALEVAR_KEY: &[u8] = b"persist.sys.localevar\0";
// Ported from https://android.googlesource.com/platform/frameworks/base/+/refs/heads/master/core/jni/AndroidRuntime.cpp#431
fn read_locale() -> Option<String> {
if let Some(locale) = get_property(LOCALE_KEY) {
return Some(locale);
}
// Android 4.0 and below
if let Some(mut language) = get_property(LANG_KEY) {
// The details of this functionality are not publically available, so this is just
// adapted "best effort" from the original code.
match get_property(COUNTRY_KEY) {
Some(country) => {
language.push('-');
language.push_str(&country);
}
None => {
if let Some(variant) = get_property(LOCALEVAR_KEY) {
language.push('-');
language.push_str(&variant);
}
}
};
return Some(language);
}
if let Some(locale) = get_property(PRODUCT_LOCALE_KEY) {
return Some(locale);
}
let product_language = get_property(PRODUCT_LANGUAGE_KEY);
let product_region = get_property(PRODUCT_REGION_KEY);
match (product_language, product_region) {
(Some(mut lang), Some(region)) => {
lang.push('-');
lang.push_str(®ion);
Some(lang)
}
_ => None,
}
}
pub(crate) fn get() -> impl Iterator<Item = String> {
read_locale().into_iter()
}