test/run_input: add frontend for InputPlugin::scan_tags()

test/run_input.cxx

@@ -23,6 +23,9 @@
 #include "config/ConfigGlobal.hxx"
 #include "input/InputStream.hxx"
 #include "input/Init.hxx"
+#include "input/Registry.hxx"
+#include "input/InputPlugin.hxx"
+#include "input/RemoteTagScanner.hxx"
 #include "event/Thread.hxx"
 #include "thread/Cond.hxx"
 #include "Log.hxx"
@@ -49,16 +52,20 @@ struct CommandLine {
 	Path config_path = nullptr;
 
 	bool verbose = false;
+
+	bool scan = false;
 };
 
 enum Option {
 	OPTION_CONFIG,
 	OPTION_VERBOSE,
+	OPTION_SCAN,
 };
 
 static constexpr OptionDef option_defs[] = {
 	{"config", 0, true, "Load a MPD configuration file"},
 	{"verbose", 'v', false, "Verbose logging"},
+	{"scan", 0, false, "Scan tags instead of reading raw data"},
 };
 
 static CommandLine
@@ -76,6 +83,10 @@ ParseCommandLine(int argc, char **argv)
 		case OPTION_VERBOSE:
 			c.verbose = true;
 			break;
+
+		case OPTION_SCAN:
+			c.scan = true;
+			break;
 		}
 	}
 
@@ -160,6 +171,64 @@ dump_input_stream(InputStream *is)
 	return 0;
 }
 
+class DumpRemoteTagHandler final : public RemoteTagHandler {
+	Mutex mutex;
+	Cond cond;
+
+	Tag tag;
+	std::exception_ptr error;
+
+	bool done = false;
+
+public:
+	Tag Wait() {
+		const std::lock_guard<Mutex> lock(mutex);
+		while (!done)
+			cond.wait(mutex);
+
+		if (error)
+			std::rethrow_exception(error);
+
+		return std::move(tag);
+	}
+
+	/* virtual methods from RemoteTagHandler */
+	void OnRemoteTag(Tag &&_tag) noexcept override {
+		const std::lock_guard<Mutex> lock(mutex);
+		tag = std::move(_tag);
+		done = true;
+		cond.broadcast();
+	}
+
+	void OnRemoteTagError(std::exception_ptr e) noexcept override {
+		const std::lock_guard<Mutex> lock(mutex);
+		error = std::move(e);
+		done = true;
+		cond.broadcast();
+	}
+};
+
+static int
+Scan(const char *uri)
+{
+	DumpRemoteTagHandler handler;
+
+	input_plugins_for_each_enabled(plugin) {
+		if (plugin->scan_tags == nullptr)
+			continue;
+
+		auto scanner = plugin->scan_tags(uri, handler);
+		if (scanner) {
+			scanner->Start();
+			tag_save(stdout, handler.Wait());
+			return EXIT_SUCCESS;
+		}
+	}
+
+	fprintf(stderr, "Unsupported URI\n");
+	return EXIT_FAILURE;
+}
+
 int main(int argc, char **argv)
 try {
 	const auto c = ParseCommandLine(argc, argv);
@@ -168,6 +237,9 @@ try {
 
 	const GlobalInit init(c.config_path, c.verbose);
 
+	if (c.scan)
+		return Scan(c.uri);
+
 	/* open the stream and dump it */
 
 	Mutex mutex;