decoder/Thread: catch exceptions

Allow decoders to throw std::runtime_error.

src/decoder/DecoderThread.cxx

@@ -39,6 +39,7 @@
 #include "tag/ApeReplayGain.hxx"
 #include "Log.hxx"
 
+#include <stdexcept>
 #include <functional>
 #include <memory>
 
@@ -351,10 +352,29 @@ decoder_run_file(Decoder &decoder, const char *uri_utf8, Path path_fs)
  */
 static bool
 DecoderUnlockedRunUri(Decoder &decoder, const char *real_uri, Path path_fs)
-{
+try {
 	return !path_fs.IsNull()
 		? decoder_run_file(decoder, real_uri, path_fs)
 		: decoder_run_stream(decoder, real_uri);
+} catch (const std::runtime_error &e) {
+	/* copy the exception to decoder.error */
+
+	if (decoder.error.IsDefined()) {
+		/* decoder.error already set, now we have a second
+		   one; only log the second one */
+		LogError(e);
+		return false;
+	}
+
+	const char *error_uri = real_uri;
+	const std::string allocated = uri_remove_auth(error_uri);
+	if (!allocated.empty())
+		error_uri = allocated.c_str();
+
+	decoder.error.Format(decoder_domain,
+			     "Failed to decode %s: %s",
+			     error_uri, e.what());
+	return false;
 }
 
 /**