1 files changed, 100 insertions, 0 deletions
diff --git a/alacritty/src/macos/locale.rs b/alacritty/src/macos/locale.rs
new file mode 100644
index 00000000..6c02c12c
--- /dev/null
+++ b/alacritty/src/macos/locale.rs
@@ -0,0 +1,100 @@
+#![allow(clippy::let_unit_value)]
+
+use std::env;
+use std::ffi::{CStr, CString};
+use std::os::raw::c_char;
+use std::slice;
+use std::str;
+
+use libc::{setlocale, LC_ALL, LC_CTYPE};
+use log::debug;
+use objc::runtime::{Class, Object};
+use objc::{msg_send, sel, sel_impl};
+
+const FALLBACK_LOCALE: &str = "UTF-8";
+
+pub fn set_locale_environment() {
+    let env_locale_c = CString::new("").unwrap();
+    let env_locale_ptr = unsafe { setlocale(LC_ALL, env_locale_c.as_ptr()) };
+    if !env_locale_ptr.is_null() {
+        let env_locale = unsafe { CStr::from_ptr(env_locale_ptr).to_string_lossy() };
+
+        // Assume `C` locale means unchanged, since it is the default anyways.
+        if env_locale != "C" {
+            debug!("Using environment locale: {}", env_locale);
+            return;
+        }
+    }
+
+    let system_locale = system_locale();
+
+    // Set locale to system locale.
+    let system_locale_c = CString::new(system_locale.clone()).expect("nul byte in system locale");
+    let lc_all = unsafe { setlocale(LC_ALL, system_locale_c.as_ptr()) };
+
+    // Check if system locale was valid or not.
+    if lc_all.is_null() {
+        // Use fallback locale.
+        debug!("Using fallback locale: {}", FALLBACK_LOCALE);
+
+        let fallback_locale_c = CString::new(FALLBACK_LOCALE).unwrap();
+        unsafe { setlocale(LC_CTYPE, fallback_locale_c.as_ptr()) };
+
+        env::set_var("LC_CTYPE", FALLBACK_LOCALE);
+    } else {
+        // Use system locale.
+        debug!("Using system locale: {}", system_locale);
+
+        env::set_var("LC_ALL", system_locale);
+    }
+}
+
+/// Determine system locale based on language and country code.
+fn system_locale() -> String {
+    unsafe {
+        let locale_class = Class::get("NSLocale").unwrap();
+        let locale: *const Object = msg_send![locale_class, currentLocale];
+        let _: () = msg_send![locale_class, release];
+
+        // `localeIdentifier` returns extra metadata with the locale (including currency and
+        // collator) on newer versions of macOS. This is not a valid locale, so we use
+        // `languageCode` and `countryCode`, if they're available (macOS 10.12+):
+        //
+        // https://developer.apple.com/documentation/foundation/nslocale/1416263-localeidentifier?language=objc
+        // https://developer.apple.com/documentation/foundation/nslocale/1643060-countrycode?language=objc
+        // https://developer.apple.com/documentation/foundation/nslocale/1643026-languagecode?language=objc
+        let is_language_code_supported: bool =
+            msg_send![locale, respondsToSelector: sel!(languageCode)];
+        let is_country_code_supported: bool =
+            msg_send![locale, respondsToSelector: sel!(countryCode)];
+        let locale_id = if is_language_code_supported && is_country_code_supported {
+            let language_code: *const Object = msg_send![locale, languageCode];
+            let language_code_str = nsstring_as_str(language_code).to_owned();
+            let _: () = msg_send![language_code, release];
+
+            let country_code: *const Object = msg_send![locale, countryCode];
+            let country_code_str = nsstring_as_str(country_code).to_owned();
+            let _: () = msg_send![country_code, release];
+
+            format!("{}_{}.UTF-8", &language_code_str, &country_code_str)
+        } else {
+            let identifier: *const Object = msg_send![locale, localeIdentifier];
+            let identifier_str = nsstring_as_str(identifier).to_owned();
+            let _: () = msg_send![identifier, release];
+
+            identifier_str + ".UTF-8"
+        };
+
+        let _: () = msg_send![locale, release];
+
+        locale_id
+    }
+}
+
+const UTF8_ENCODING: usize = 4;
+
+unsafe fn nsstring_as_str<'a>(nsstring: *const Object) -> &'a str {
+    let cstr: *const c_char = msg_send![nsstring, UTF8String];
+    let len: usize = msg_send![nsstring, lengthOfBytesUsingEncoding: UTF8_ENCODING];
+    str::from_utf8(slice::from_raw_parts(cstr as *const u8, len)).unwrap()
+}