[Intl] Add polyfill for Locale::canonicalize()

Author: nicolas-grekas

Locale/Locale.php

@@ -16,8 +16,8 @@
 /**
  * Replacement for PHP's native {@link \Locale} class.
  *
- * The only method supported in this class is {@link getDefault}. This method
- * will always return "en". All other methods will throw an exception when used.
+ * The only methods supported in this class are `getDefault` and `canonicalize`.
+ * All other methods will throw an exception when used.
  *
  * @author Eriksen Costa <eriksen.costa@infranology.com.br>
  * @author Bernhard Schussek <bschussek@gmail.com>
@@ -57,6 +57,39 @@ public static function acceptFromHttp($header)
         throw new MethodNotImplementedException(__METHOD__);
     }
 
+    /**
+     * Returns a canonicalized locale string.
+     *
+     * This polyfill doesn't implement the full-spec algorithm. It only
+     * canonicalizes locale strings handled by the `LocaleBundle` class.
+     *
+     * @param string $locale
+     *
+     * @return string
+     */
+    public static function canonicalize($locale)
+    {
+        $locale = (string) $locale;
+
+        if ('' === $locale || '.' === $locale[0]) {
+            return self::getDefault();
+        }
+
+        if (!preg_match('/^([a-z]{2})[-_]([a-z]{2})(?:([a-z]{2})(?:[-_]([a-z]{2}))?)?(?:\..*)?$/i', $locale, $m)) {
+            return $locale;
+        }
+
+        if (!empty($m[4])) {
+            return strtolower($m[1]).'_'.ucfirst(strtolower($m[2].$m[3])).'_'.strtoupper($m[4]);
+        }
+
+        if (!empty($m[3])) {
+            return strtolower($m[1]).'_'.ucfirst(strtolower($m[2].$m[3]));
+        }
+
+        return strtolower($m[1]).'_'.strtoupper($m[2]);
+    }
+
     /**
      * Not supported. Returns a correctly ordered and delimited locale code.
      *

Tests/Locale/LocaleTest.php

@@ -21,6 +21,17 @@ public function testAcceptFromHttp()
         $this->call('acceptFromHttp', 'pt-br,en-us;q=0.7,en;q=0.5');
     }
 
+    public function testCanonicalize()
+    {
+        $this->assertSame('en', $this->call('canonicalize', ''));
+        $this->assertSame('en', $this->call('canonicalize', '.utf8'));
+        $this->assertSame('fr_FR', $this->call('canonicalize', 'FR-fr'));
+        $this->assertSame('fr_FR', $this->call('canonicalize', 'FR-fr.utf8'));
+        $this->assertSame('uz_Latn', $this->call('canonicalize', 'UZ-lATN'));
+        $this->assertSame('uz_Cyrl_UZ', $this->call('canonicalize', 'UZ-cYRL-uz'));
+        $this->assertSame('123', $this->call('canonicalize', 123));
+    }
+
     /**
      * @expectedException \Symfony\Component\Intl\Exception\MethodNotImplementedException
      */