locale: Add translations for layout names

Pulled in some Unix-specific code from https://github.com/rust-locale/locale_config to reduce dependencies.

First reason to reduce dependencies: gettext-rs is not in Debian. Copying gettext-sys might have made sense, but the interface is somewhat confusing.

For translating a couple identifiers, detection and some hand-rolled hash map is all that is needed, and the option to move to gettext later remains.

locale_config has been stripped of the lazy_static dependency, which, messing with the strtup sequence, might be a source of debugging woes. Plus setting language once in the beginning is somewhat inflexible regarding runtime changes.

src/resources.rs

@@ -2,6 +2,13 @@
  * This could be done using GResource, but that would need additional work.
  */
 
+use std::collections::HashMap;
+
+use std::iter::FromIterator;
+
+// TODO: keep a list of what is a language layout,
+// and what a convenience layout. "_wide" is not a layout,
+// neither is "number"
 const KEYBOARDS: &[(*const str, *const str)] = &[
     ("us", include_str!("../data/keyboards/us.yaml")),
     ("us_wide", include_str!("../data/keyboards/us_wide.yaml")),
@@ -27,3 +34,76 @@ pub fn get_keyboard(needle: &str) -> Option<&'static str> {
             unsafe { &*value }
         })
 }
+
+/// Translations of the layout identifier strings
+const LAYOUT_NAMES: &[(*const str, *const str)] = &[
+    ("en-US", include_str!("../data/langs/en-US.txt")),
+    ("pl-PL", include_str!("../data/langs/pl-PL.txt")),
+];
+
+pub fn get_layout_names(lang: &str)
+    -> Option<HashMap<&'static str, &'static str>>
+{
+    let translations = LAYOUT_NAMES.iter()
+        .find(|(name, _data)| {
+            let name: *const str = *name;
+            (unsafe { &*name }) == lang
+        })
+        .map(|(_name, data)| {
+            let data: *const str = *data;
+            unsafe { &*data }
+        });
+    translations.map(make_mapping)
+}
+
+fn parse_line(line: &str) -> Option<(&str, &str)> {
+    let comment = line.trim().starts_with("#");
+    if comment {
+        None
+    } else {
+        let mut iter = line.splitn(2, " ");
+        let name = iter.next().unwrap();
+        // will skip empty and unfinished lines
+        iter.next().map(|tr| (name, tr.trim()))
+    }
+}
+
+fn make_mapping(data: &str) -> HashMap<&str, &str> {
+    HashMap::from_iter(
+        data.split("\n")
+            .filter_map(parse_line)
+    )
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn mapping_line() {
+        assert_eq!(
+            Some(("name", "translation")),
+            parse_line("name translation")
+        );
+    }
+
+    #[test]
+    fn mapping_bad() {
+        assert_eq!(None, parse_line("bad"));
+    }
+
+    #[test]
+    fn mapping_empty() {
+        assert_eq!(None, parse_line(""));
+    }
+
+    #[test]
+    fn mapping_comment() {
+        assert_eq!(None, parse_line("# comment"));
+    }
+
+    #[test]
+    fn mapping_comment_offset() {
+        assert_eq!(None, parse_line("  # comment"));
+    }
+}