PlaylistFile: move memchr() call to class Path

src/PlaylistFile.cxx

@@ -169,11 +169,13 @@ LoadPlaylistFileInfo(PlaylistInfo &info,
 		     const Path parent_path_fs,
 		     const Path name_fs)
 {
+	if (name_fs.HasNewline())
+		return false;
+
 	const auto *const name_fs_str = name_fs.c_str();
 	const size_t name_length = name_fs.length();
 
-	if (name_length < ARRAY_SIZE(PLAYLIST_FILE_SUFFIX) ||
-	    memchr(name_fs_str, '\n', name_length) != nullptr)
+	if (name_length < ARRAY_SIZE(PLAYLIST_FILE_SUFFIX))
 		return false;
 
 	if (!StringEndsWith(name_fs_str, PLAYLIST_FILE_SUFFIX))

src/fs/Path.hxx

@@ -123,6 +123,16 @@ public:
 	}
 
 	/**
+	 * Does the path contain a newline character?  (Which is
+	 * usually rejected by MPD because its protocol cannot
+	 * transfer newline characters).
+	 */
+	gcc_pure
+	bool HasNewline() const {
+		return strchr(value, '\n') != nullptr;
+	}
+
+	/**
 	 * Convert the path to UTF-8.
 	 * Returns empty string on error or if this instance is "nulled"
 	 * (#IsNull returns true).