Improve some settings-related performance

Summary:
Ref T4103. Two small improvements:

  - Don't work as hard to validate translations. We just need to know if a translation exists, we don't need to count how many strings it has and build the entire menu.
  - Allow `getUserSetting()` to work on any setting without doing all the application/visibility checks. It's OK for code to look at, say, your "Conpherence Notifications" setting even if that application is not installed for you.

Test Plan: Used XHProf and saw 404 page drop from ~60ms to ~40ms locally.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T4103

Differential Revision: https://secure.phabricator.com/D16046

src/applications/home/application/PhabricatorHomeApplication.php

@@ -2,6 +2,7 @@
 
 final class PhabricatorHomeApplication extends PhabricatorApplication {
 
+  private $quickItems;
   const DASHBOARD_DEFAULT = 'dashboard:default';
 
   public function getBaseURI() {
@@ -42,6 +43,11 @@ final class PhabricatorHomeApplication extends PhabricatorApplication {
     PhabricatorUser $user,
     PhabricatorController $controller = null) {
 
+    $quick_items = $this->getQuickActionItems($user);
+    if (!$quick_items) {
+      return array();
+    }
+
     $items = array();
     $create_id = celerity_generate_unique_node_id();
 
@@ -73,7 +79,7 @@ final class PhabricatorHomeApplication extends PhabricatorApplication {
     PhabricatorUser $viewer,
     PhabricatorController $controller = null) {
 
-    $items = PhabricatorQuickActions::loadMenuItemsForUser($viewer);
+    $items = $this->getQuickActionItems($viewer);
 
     $view = null;
     if ($items) {
@@ -94,4 +100,12 @@ final class PhabricatorHomeApplication extends PhabricatorApplication {
     return $view;
   }
 
+  private function getQuickActionItems(PhabricatorUser $viewer) {
+    if ($this->quickItems === null) {
+      $items = PhabricatorQuickActions::loadMenuItemsForUser($viewer);
+      $this->quickItems = $items;
+    }
+    return $this->quickItems;
+  }
+
 }

src/applications/people/storage/PhabricatorUser.php

@@ -486,7 +486,10 @@ final class PhabricatorUser
       $settings = array();
     }
 
-    $defaults = PhabricatorSetting::getAllEnabledSettings($this);
+    // NOTE: To slightly improve performance, we're using all settings here,
+    // not just settings that are enabled for the current viewer. It's fine to
+    // get the value of a setting that we wouldn't let the user edit in the UI.
+    $defaults = PhabricatorSetting::getAllSettings();
 
     if (array_key_exists($key, $settings)) {
       $value = $settings[$key];

src/applications/settings/setting/PhabricatorTranslationSetting.php

@@ -26,6 +26,11 @@ final class PhabricatorTranslationSetting
       'Choose which language you would like the Phabricator UI to use.');
   }
 
+  public function assertValidValue($value) {
+    $locales = PhutilLocale::loadAllLocales();
+    return isset($locales[$value]);
+  }
+
   protected function getSelectOptionGroups() {
     $is_serious = PhabricatorEnv::getEnvConfig('phabricator.serious-business');
     $locales = PhutilLocale::loadAllLocales();