Add a new function to get locale

Author: kingysu

src/lib/fcitx/instance.cpp

@@ -185,22 +185,13 @@ void InstanceArgument::printUsage() const {
 
 InstancePrivate::InstancePrivate(Instance *q) : QPtrHolder<Instance>(q) {
 #ifdef ENABLE_KEYBOARD
-    auto locale = getEnvironment("LC_ALL");
-    if (!locale) {
-        locale = getEnvironment("LC_CTYPE");
-    }
-    if (!locale) {
-        locale = getEnvironment("LANG");
-    }
-    if (!locale) {
-        locale = "C";
-    }
-    assert(locale.has_value());
+    const auto locale = getLocale();
+    assert(!locale.empty());
     xkbContext_.reset(xkb_context_new(XKB_CONTEXT_NO_FLAGS));
     if (xkbContext_) {
         xkb_context_set_log_level(xkbContext_.get(), XKB_LOG_LEVEL_CRITICAL);
         xkbComposeTable_.reset(xkb_compose_table_new_from_locale(
-            xkbContext_.get(), locale->data(), XKB_COMPOSE_COMPILE_NO_FLAGS));
+            xkbContext_.get(), locale.data(), XKB_COMPOSE_COMPILE_NO_FLAGS));
         if (!xkbComposeTable_) {
             FCITX_INFO()
                 << "Trying to fallback to compose table for en_US.UTF-8";
@@ -224,6 +215,18 @@ InstancePrivate::watchEvent(EventType type, EventWatcherPhase phase,
 }
 
 #ifdef ENABLE_KEYBOARD
+std::string InstancePrivate::getLocale() {
+    const char *const variableList[] = {"LC_ALL", "LC_CTYPE", "LANG"};
+    for (const char *variable : variableList) {
+        const auto locale = getEnvironment(variable);
+        if (locale.has_value()) {
+            return locale.value();
+        }
+    }
+
+    return "C";
+}
+
 xkb_keymap *InstancePrivate::keymap(const std::string &display,
                                     const std::string &layout,
                                     const std::string &variant) {

src/lib/fcitx/instance_p.h

@@ -133,6 +133,8 @@ class InstancePrivate : public QPtrHolder<Instance> {
     watchEvent(EventType type, EventWatcherPhase phase, EventHandler callback);
 
 #ifdef ENABLE_KEYBOARD
+    static std::string getLocale();
+
     xkb_keymap *keymap(const std::string &display, const std::string &layout,
                        const std::string &variant);
 #endif