[Intl] Add FallbackTrait for data generation

src/Symfony/Component/Intl/Data/Generator/FallbackTrait.php

@@ -0,0 +1,73 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Intl\Data\Generator;
+
+use Symfony\Component\Intl\Data\Bundle\Reader\BundleEntryReaderInterface;
+use Symfony\Component\Intl\Locale;
+
+/**
+ * @author Roland Franssen <franssen.roland@gmail.com>
+ *
+ * @internal
+ */
+trait FallbackTrait
+{
+    private $fallbackCache = [];
+    private $generatingFallback = false;
+
+    /**
+     * @param string $tempDir
+     * @param string $displayLocale
+     *
+     * @return array|null
+     *
+     * @see AbstractDataGenerator::generateDataForLocale()
+     */
+    abstract protected function generateDataForLocale(BundleEntryReaderInterface $reader, $tempDir, $displayLocale);
+
+    /**
+     * @param string $tempDir
+     *
+     * @return array|null
+     *
+     * @see AbstractDataGenerator::generateDataForRoot()
+     */
+    abstract protected function generateDataForRoot(BundleEntryReaderInterface $reader, $tempDir);
+
+    /**
+     * @param string $tempDir
+     * @param string $displayLocale
+     *
+     * @return array
+     */
+    private function generateFallbackData(BundleEntryReaderInterface $reader, $tempDir, $displayLocale)
+    {
+        if (null === $fallback = Locale::getFallback($displayLocale)) {
+            return [];
+        }
+
+        if (isset($this->fallbackCache[$fallback])) {
+            return $this->fallbackCache[$fallback];
+        }
+
+        $prevGeneratingFallback = $this->generatingFallback;
+        $this->generatingFallback = true;
+
+        try {
+            $data = 'root' === $fallback ? $this->generateDataForRoot($reader, $tempDir) : $this->generateDataForLocale($reader, $tempDir, $fallback);
+        } finally {
+            $this->generatingFallback = $prevGeneratingFallback;
+        }
+
+        return $this->fallbackCache[$fallback] = $data ?: [];
+    }
+}

src/Symfony/Component/Intl/Data/Generator/LocaleDataGenerator.php

@@ -16,7 +16,6 @@ use Symfony\Component\Intl\Data\Bundle\Compiler\BundleCompilerInterface;
 use Symfony\Component\Intl\Data\Bundle\Reader\BundleEntryReaderInterface;
 use Symfony\Component\Intl\Data\Util\LocaleScanner;
 use Symfony\Component\Intl\Exception\MissingResourceException;
-use Symfony\Component\Intl\Locale;
 
 /**
  * The rule for compiling the locale bundle.
@@ -28,10 +27,10 @@ use Symfony\Component\Intl\Locale;
  */
 class LocaleDataGenerator extends AbstractDataGenerator
 {
-    private $locales;
-    private $localeAliases;
-    private $fallbackMapping;
-    private $fallbackCache = [];
+    use FallbackTrait;
+
+    private $locales = [];
+    private $localeAliases = [];
 
     /**
      * {@inheritdoc}
@@ -40,7 +39,6 @@ class LocaleDataGenerator extends AbstractDataGenerator
     {
         $this->locales = $scanner->scanLocales($sourceDir.'/locales');
         $this->localeAliases = $scanner->scanAliases($sourceDir.'/locales');
-        $this->fallbackMapping = $this->generateFallbackMapping(array_diff($this->locales, array_keys($this->localeAliases)), $this->localeAliases);
 
         return $this->locales;
     }
@@ -64,7 +62,6 @@ class LocaleDataGenerator extends AbstractDataGenerator
      */
     protected function preGenerate()
     {
-        $this->fallbackCache = [];
     }
 
     /**
@@ -73,7 +70,8 @@ class LocaleDataGenerator extends AbstractDataGenerator
     protected function generateDataForLocale(BundleEntryReaderInterface $reader, $tempDir, $displayLocale)
     {
         // Don't generate aliases, as they are resolved during runtime
-        if (isset($this->localeAliases[$displayLocale])) {
+        // Unless an alias is needed as fallback for de-duplication purposes
+        if (isset($this->localeAliases[$displayLocale]) && !$this->generatingFallback) {
             return;
         }
 
@@ -85,7 +83,7 @@ class LocaleDataGenerator extends AbstractDataGenerator
         $localeNames = [];
         foreach ($this->locales as $locale) {
             // Ensure a normalized list of pure locales
-            if (isset($this->localeAliases[$displayLocale]) || \Locale::getAllVariants($locale)) {
+            if (\Locale::getAllVariants($locale)) {
                 continue;
             }
 
@@ -102,21 +100,27 @@ class LocaleDataGenerator extends AbstractDataGenerator
             }
         }
 
-        // Process again to de-duplicate locales and their fallback locales
-        // Only keep the differences
-        $fallback = $displayLocale;
-        while (isset($this->fallbackMapping[$fallback])) {
-            if (!isset($this->fallbackCache[$fallback = $this->fallbackMapping[$fallback]])) {
-                $this->fallbackCache[$fallback] = $this->generateDataForLocale($reader, $tempDir, $fallback) ?: [];
-            }
-            if (isset($this->fallbackCache[$fallback]['Names'])) {
-                $localeNames = array_diff($localeNames, $this->fallbackCache[$fallback]['Names']);
-            }
+        $data = [
+            'Names' => $localeNames,
+        ];
+
+        // Don't de-duplicate a fallback locale
+        // Ensures the display locale can be de-duplicated on itself
+        if ($this->generatingFallback) {
+            return $data;
         }
 
-        if ($localeNames) {
-            return ['Names' => $localeNames];
+        // Process again to de-duplicate locale and its fallback locales
+        // Only keep the differences
+        $fallbackData = $this->generateFallbackData($reader, $tempDir, $displayLocale);
+        if (isset($fallbackData['Names'])) {
+            $data['Names'] = array_diff($data['Names'], $fallbackData['Names']);
         }
+        if (!$data['Names']) {
+            return;
+        }
+
+        return $data;
     }
 
     /**
@@ -131,12 +135,10 @@ class LocaleDataGenerator extends AbstractDataGenerator
      */
     protected function generateDataForMeta(BundleEntryReaderInterface $reader, $tempDir)
     {
-        if ($this->locales || $this->localeAliases) {
-            return [
-                'Locales' => $this->locales,
-                'Aliases' => $this->localeAliases,
-            ];
-        }
+        return [
+            'Locales' => $this->locales,
+            'Aliases' => $this->localeAliases,
+        ];
     }
 
     /**
@@ -175,30 +177,4 @@ class LocaleDataGenerator extends AbstractDataGenerator
 
         return $name;
     }
-
-    private function generateFallbackMapping(array $displayLocales, array $aliases)
-    {
-        $displayLocales = array_flip($displayLocales);
-        $mapping = [];
-
-        foreach ($displayLocales as $displayLocale => $_) {
-            $mapping[$displayLocale] = null;
-            $fallback = $displayLocale;
-
-            // Recursively search for a fallback locale until one is found
-            while (null !== ($fallback = Locale::getFallback($fallback))) {
-                // Currently, no locale has an alias as fallback locale.
-                // If this starts to be the case, we need to add code here.
-                \assert(!isset($aliases[$fallback]));
-
-                // Check whether the fallback exists
-                if (isset($displayLocales[$fallback])) {
-                    $mapping[$displayLocale] = $fallback;
-                    break;
-                }
-            }
-        }
-
-        return $mapping;
-    }
 }