decoder/audiofile: use AtScopeExit()

src/decoder/plugins/AudiofileDecoderPlugin.cxx

@@ -23,6 +23,7 @@
 #include "input/InputStream.hxx"
 #include "CheckAudioFormat.hxx"
 #include "tag/TagHandler.hxx"
+#include "util/ScopeExit.hxx"
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
 #include "Log.hxx"
@@ -195,6 +196,8 @@ audiofile_stream_decode(Decoder &decoder, InputStream &is)
 	if (fh == AF_NULL_FILEHANDLE)
 		return;
 
+	AtScopeExit(fh) { afCloseFile(fh); };
+
 	Error error;
 	AudioFormat audio_format;
 	if (!audio_format_init_checked(audio_format,
@@ -203,7 +206,6 @@ audiofile_stream_decode(Decoder &decoder, InputStream &is)
 				       afGetVirtualChannels(fh, AF_DEFAULT_TRACK),
 				       error)) {
 		LogError(error);
-		afCloseFile(fh);
 		return;
 	}
 
@@ -240,8 +242,6 @@ audiofile_stream_decode(Decoder &decoder, InputStream &is)
 			cmd = DecoderCommand::NONE;
 		}
 	} while (cmd == DecoderCommand::NONE);
-
-	afCloseFile(fh);
 }
 
 gcc_pure