[libcalamares] Compare translation IDs, extend find()

Allow naive comparison of translation IDs (e.g. "ca@valencia"
against other IDs) and make it easier to find one.

src/libcalamares/locale/Translation.h

@@ -117,6 +117,11 @@ operator<<( QDebug& s, const Translation::Id& id )
 {
     return s << id.name;
 }
+static inline bool
+operator==( const Translation::Id& lhs, const Translation::Id& rhs )
+{
+    return lhs.name == rhs.name;
+}
 
 }  // namespace Locale
 }  // namespace CalamaresUtils

src/libcalamares/locale/TranslationsModel.cpp

@@ -121,8 +121,8 @@ TranslationsModel::find( const QString& countryCode ) const
     }
 
     auto c_l = countryData( countryCode );
-    int r = find(
+    int r = find( [ & ]( const Translation& l )
-        [&]( const Translation& l ) { return ( l.language() == c_l.second ) && ( l.country() == c_l.first ); } );
+                  { return ( l.language() == c_l.second ) && ( l.country() == c_l.first ); } );
     if ( r >= 0 )
     {
         return r;
@@ -130,6 +130,12 @@ TranslationsModel::find( const QString& countryCode ) const
     return find( [ & ]( const Translation& l ) { return l.language() == c_l.second; } );
 }
 
+int
+TranslationsModel::find( const Translation::Id& id ) const
+{
+    return find( [ & ]( const Translation& l ) { return l.id() == id; } );
+}
+
 TranslationsModel*
 availableTranslations()
 {

src/libcalamares/locale/TranslationsModel.h

@@ -63,6 +63,8 @@ public:
     int find( const QLocale& ) const;
     /// @brief Looks for an item that best matches the 2-letter country code
     int find( const QString& countryCode ) const;
+    /// @brief Looks up a translation Id
+    int find( const Translation::Id& id ) const;
 
 private:
     QVector< Translation* > m_locales;