input/Plugin: migrate init() from class Error to C++ exceptions

test/run_input.cxx

@@ -34,6 +34,8 @@
 #include "archive/ArchiveList.hxx"
 #endif
 
+#include <stdexcept>
+
 #include <unistd.h>
 #include <stdlib.h>
 
@@ -91,7 +93,7 @@ dump_input_stream(InputStream *is)
 }
 
 int main(int argc, char **argv)
-{
+try {
 	if (argc != 2) {
 		fprintf(stderr, "Usage: run_input URI\n");
 		return EXIT_FAILURE;
@@ -108,10 +110,7 @@ int main(int argc, char **argv)
 #endif
 
 	Error error;
-	if (!input_stream_global_init(error)) {
-		LogError(error);
-		return 2;
-	}
+	input_stream_global_init();
 
 	/* open the stream and dump it */
 
@@ -142,4 +141,7 @@ int main(int argc, char **argv)
 	config_global_finish();
 
 	return ret;
+} catch (const std::exception &e) {
+	LogError(e);
+	return EXIT_FAILURE;
 }