Allow 4byte unicode filenames on supported platforms

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/private/DB/Connection.php

@@ -33,6 +33,7 @@ use Doctrine\DBAL\Driver;
 use Doctrine\DBAL\Configuration;
 use Doctrine\DBAL\Cache\QueryCacheProfile;
 use Doctrine\Common\EventManager;
+use Doctrine\DBAL\Platforms\MySqlPlatform;
 use OC\DB\QueryBuilder\QueryBuilder;
 use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\IDBConnection;
@@ -402,4 +403,14 @@ class Connection extends \Doctrine\DBAL\Connection implements IDBConnection {
 	public function escapeLikeParameter($param) {
 		return addcslashes($param, '\\_%');
 	}
+
+	/**
+	 * Check whether or not the current database support 4byte wide unicode
+	 *
+	 * @return bool
+	 * @since 9.2.0
+	 */
+	public function supports4ByteText() {
+		return ! ($this->getDatabasePlatform() instanceof MySqlPlatform && $this->getParams()['charset'] !== 'utf8mb4');
+	}
 }

lib/private/Files/View.php

@@ -1806,13 +1806,15 @@ class View {
 			throw new InvalidPathException($l10n->t('Dot files are not allowed'));
 		}
 
-		// verify database - e.g. mysql only 3-byte chars
-		if (preg_match('%(?:
+		if (!\OC::$server->getDatabaseConnection()->supports4ByteText()) {
+			// verify database - e.g. mysql only 3-byte chars
+			if (preg_match('%(?:
       \xF0[\x90-\xBF][\x80-\xBF]{2}      # planes 1-3
     | [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
     | \xF4[\x80-\x8F][\x80-\xBF]{2}      # plane 16
 )%xs', $fileName)) {
-			throw new InvalidPathException($l10n->t('4-byte characters are not supported in file names'));
+				throw new InvalidPathException($l10n->t('4-byte characters are not supported in file names'));
+			}
 		}
 
 		try {

lib/public/IDBConnection.php

@@ -251,4 +251,12 @@ interface IDBConnection {
 	 * @since 9.0.0
 	 */
 	public function escapeLikeParameter($param);
+
+	/**
+	 * Check whether or not the current database support 4byte wide unicode
+	 *
+	 * @return bool
+	 * @since 9.2.0
+	 */
+	public function supports4ByteText();
 }