translations: Make the code cleaner

src/locale.rs

@@ -1,4 +1,10 @@
-/*! Locale-specific functions. */
+/*! Locale-specific functions. 
+ * 
+ * This file is intended as a library:
+ * it must pass errors upwards
+ * and panicking is allowed only when
+ * this code encounters an internal inconsistency.
+ */
 
 use std::cmp;
 use std::ffi::{ CStr, CString };

src/logging.rs

@@ -70,12 +70,12 @@ pub enum Level {
 /// Approach 2.
 pub trait Warn {
     type Value;
-    fn ok_warn(self, msg: &str) -> Option<Self::Value>;
+    fn or_warn(self, msg: &str) -> Option<Self::Value>;
 }
 
 impl<T, E: Error> Warn for Result<T, E> {
     type Value = T;
-    fn ok_warn(self, msg: &str) -> Option<T> {
+    fn or_warn(self, msg: &str) -> Option<T> {
         self.map_err(|e| {
             eprintln!("{}: {}", msg, e);
             e
@@ -83,6 +83,16 @@ impl<T, E: Error> Warn for Result<T, E> {
     }
 }
 
+impl<T> Warn for Option<T> {
+    type Value = T;
+    fn or_warn(self, msg: &str) -> Option<T> {
+        self.or_else(|| {
+            eprintln!("{}", msg);
+            None
+        })
+    }
+}
+
 /// A mutable handler for text warnings.
 /// Approach 3.
 pub trait WarningHandler {

src/popover.rs

@@ -18,6 +18,7 @@ use glib::variant::ToVariant;
 use gtk::PopoverExt;
 use gtk::WidgetExt;
 use std::io::Write;
+use ::logging::Warn;
 
 mod variants {
     use glib;
@@ -195,6 +196,82 @@ fn get_current_layout(
     }
 }
 
+/// Translates all provided layout names according to current locale,
+/// for the purpose of display (i.e. errors will be caught and reported)
+fn translate_layout_names(layouts: &Vec<LayoutId>) -> Vec<OwnedTranslation> {
+    // This procedure is rather ugly...
+    // Xkb lookup *must not* be applied to non-system layouts,
+    // so both translators can't be merged into one lookup table,
+    // therefore must be done in two steps.
+    // `XkbInfo` being temporary also means
+    // that its return values must be copied,
+    // forcing the use of `OwnedTranslation`.
+    enum Status {
+        /// xkb names should get all translated here
+        Translated(OwnedTranslation),
+        /// Builtin names need builtin translations
+        Remaining(String),
+    }
+
+    // Attempt to take all xkb names from gnome-desktop's xkb info.
+    let xkb_translator = locale::XkbInfo::new();
+
+    let translated_names = layouts.iter()
+        .map(|id| match id {
+            LayoutId::System { name, kind: _ } => {
+                xkb_translator.get_display_name(name)
+                    .map(|s| Status::Translated(OwnedTranslation(s)))
+                    .unwrap_or_else(|e| {
+                        eprintln!(
+                            "No display name for xkb layout {}: {:?}",
+                            name,
+                            e,
+                        );
+                        Status::Remaining(name.clone())
+                    })
+            },
+            LayoutId::Local(name) => Status::Remaining(name.clone()),
+        });
+
+    // Non-xkb layouts and weird xkb layouts
+    // still need to be looked up in the internal database.
+    let builtin_translations = system_locale()
+        .map(|locale|
+            locale.tags_for("messages")
+                .next().unwrap() // guaranteed to exist
+                .as_ref()
+                .to_owned()
+        )
+        .or_warn("No locale detected")
+        .and_then(|lang| {
+            resources::get_layout_names(lang.as_str())
+                .or_warn(&format!("No translations for locale {}", lang))
+        });
+
+    match builtin_translations {
+        Some(translations) => {
+            translated_names
+                .map(|status| match status {
+                    Status::Remaining(name) => {
+                        translations.get(name.as_str())
+                            .unwrap_or(&Translation(name.as_str()))
+                            .to_owned()
+                    },
+                    Status::Translated(t) => t,
+                })
+                .collect()
+        },
+        None => {
+            translated_names
+                .map(|status| match status {
+                    Status::Remaining(name) => OwnedTranslation(name),
+                    Status::Translated(t) => t,
+                })
+                .collect()
+        },
+    }
+}
+
 pub fn show(
     window: EekGtkKeyboard,
     position: Bounds,
@@ -219,69 +296,8 @@ pub fn show(
         .chain(overlay_layouts)
         .collect();
 
-    let translations = system_locale()
-        .map(|locale|
-            locale.tags_for("messages")
-                .next().unwrap() // guaranteed to exist
-                .as_ref()
-                .to_owned()
-        )
-        .and_then(|lang| resources::get_layout_names(lang.as_str()));
-
-    // The actual translation procedure attempts to take all xkb names
-    // from gnome-desktop's xkb info.
-    // Remaining names are translated using the internal database,
-    // which is only available if the locale is set.
-    // The result is a rather ugly and verbose translation procedure...
-    enum Status {
-        /// xkb names should get all translated here
-        Translated(OwnedTranslation),
-        /// Builtin names need builtin translations
-        Remaining(String),
-    }
+    let translated_names = translate_layout_names(&all_layouts);
     
-    let xkb_translator = locale::XkbInfo::new();
-
-    let translated_names = all_layouts.iter()
-        .map(|id| match id {
-            LayoutId::System { name, kind: _ } => {
-                xkb_translator.get_display_name(name)
-                    .map(|s| Status::Translated(OwnedTranslation(s)))
-                    .unwrap_or_else(|e| {
-                        eprintln!(
-                            "No display name for xkb layout {}: {:?}",
-                            name,
-                            e,
-                        );
-                        Status::Remaining(name.clone())
-                    })
-            },
-            LayoutId::Local(name) => Status::Remaining(name.clone()),
-        });
-
-    let translated_names: Vec<OwnedTranslation> = match translations {
-        Some(translations) => {
-            translated_names
-                .map(|status| match status {
-                    Status::Remaining(name) => {
-                        translations.get(name.as_str())
-                            .unwrap_or(&Translation(name.as_str()))
-                            .to_owned()
-                    },
-                    Status::Translated(t) => t,
-                })
-                .collect()
-        },
-        None => {
-            translated_names
-                .map(|status| match status {
-                    Status::Remaining(name) => OwnedTranslation(name),
-                    Status::Translated(t) => t,
-                })
-                .collect()
-        },
-    };
-
     // sorted collection of human and machine names
     let mut human_names: Vec<(OwnedTranslation, LayoutId)> = translated_names
         .into_iter()

src/style.rs

@@ -16,7 +16,7 @@
  * License along with this library. If not, see <http://www.gnu.org/licenses/>.Free
  */
 
-/*! CSS data loading */
+/*! CSS data loading. */
 
 use std::env;
 
@@ -83,6 +83,7 @@ fn get_theme_name(settings: &gtk::Settings) -> GtkTheme {
         .map_err(|e| {
             match &e {
                 env::VarError::NotPresent => {},
+                // maybe TODO: forward this warning?
                 e => eprintln!("GTK_THEME variable invalid: {}", e),
             };
             e
@@ -93,13 +94,15 @@ fn get_theme_name(settings: &gtk::Settings) -> GtkTheme {
         None => GtkTheme {
             name: {
                 settings.get_property("gtk-theme-name")
-                    .ok_warn("No theme name")
+                    // maybe TODO: is this worth a warning?
+                    .or_warn("No theme name")
                     .and_then(|value| value.get::<String>())
                     .unwrap_or(DEFAULT_THEME_NAME.into())
             },
             variant: {
                 settings.get_property("gtk-application-prefer-dark-theme")
-                    .ok_warn("No settings key")
+                    // maybe TODO: is this worth a warning?
+                    .or_warn("No settings key")
                     .and_then(|value| value.get::<bool>())
                     .and_then(|dark_preferred| match dark_preferred {
                         true => Some("dark".into()),

src/util.rs

@@ -190,6 +190,11 @@ impl<T> Borrow<Rc<T>> for Pointer<T> {
     }
 }
 
+pub trait WarningHandler {
+    /// Handle a warning
+    fn handle(&mut self, warning: &str);
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;