decoder/wavpack: merge duplicate code into Scan()

src/decoder/plugins/WavpackDecoderPlugin.cxx

@@ -580,6 +580,19 @@ wavpack_filedecode(DecoderClient &client, Path path_fs)
 	wavpack_decode(client, wpc, true);
 }
 
+static void
+Scan(WavpackContext *wpc,TagHandler &handler) noexcept
+{
+	try {
+		handler.OnAudioFormat(CheckAudioFormat(wpc));
+	} catch (...) {
+	}
+
+	const auto duration = GetDuration(wpc);
+	if (!duration.IsNegative())
+		handler.OnDuration(SongTime(duration));
+}
+
 /*
  * Reads metainfo from the specified file.
  */
@@ -598,15 +611,7 @@ wavpack_scan_file(Path path_fs, TagHandler &handler) noexcept
 		WavpackCloseFile(wpc);
 	};
 
-	try {
-		handler.OnAudioFormat(CheckAudioFormat(wpc));
-	} catch (...) {
-	}
-
-	const auto duration = GetDuration(wpc);
-	if (!duration.IsNegative())
-		handler.OnDuration(SongTime(duration));
-
+	Scan(wpc, handler);
 	return true;
 }
 
@@ -627,15 +632,7 @@ wavpack_scan_stream(InputStream &is, TagHandler &handler) noexcept
 		WavpackCloseFile(wpc);
 	};
 
-	try {
-		handler.OnAudioFormat(CheckAudioFormat(wpc));
-	} catch (...) {
-	}
-
-	const auto duration = GetDuration(wpc);
-	if (!duration.IsNegative())
-		handler.OnDuration(SongTime(duration));
-
+	Scan(wpc, handler);
 	return true;
 }