diff -r 000000000000 -r c8c8ec34120f src/relpipe-in-jack.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/relpipe-in-jack.cpp	Mon May 11 20:50:54 2020 +0200
@@ -0,0 +1,205 @@
+/**
+ * Relational pipes
+ * Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <cstdlib>
+#include <cstring>
+#include <memory>
+#include <unistd.h>
+#include <signal.h>
+#include <pthread.h>
+#include <sys/mman.h>
+
+#include <jack/jack.h>
+#include <jack/midiport.h>
+#include <jack/ringbuffer.h>
+
+#include <relpipe/writer/RelationalWriter.h>
+#include <relpipe/writer/RelpipeWriterException.h>
+#include <relpipe/writer/AttributeMetadata.h>
+#include <relpipe/writer/Factory.h>
+#include <relpipe/writer/TypeId.h>
+#include <relpipe/cli/CLI.h>
+
+#include "JackException.h"
+
+using namespace relpipe::cli;
+using namespace relpipe::writer;
+using namespace relpipe::in::jack;
+
+static jack_port_t* jackPort = nullptr;
+static jack_ringbuffer_t* ringBuffer = nullptr;
+static pthread_mutex_t messageThreadLock = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t dataReady = PTHREAD_COND_INITIALIZER;
+
+static bool continueProcessing = true;
+
+const int RING_BUFFER_SIZE = 100;
+
+struct MidiMessage {
+	uint8_t buffer[4096];
+	uint32_t size;
+	uint32_t time;
+};
+
+int enqueueMessage(jack_nframes_t frames, void* arg) {
+	void* buffer = jack_port_get_buffer(jackPort, frames);
+	if (buffer == nullptr) throw JackException(L"Unable to get port buffer."); // TODO: exception in RT callback?
+
+	for (jack_nframes_t i = 0, eventCount = jack_midi_get_event_count(buffer); i < eventCount; i++) {
+		jack_midi_event_t event;
+		int noData = jack_midi_event_get(&event, buffer, i);
+		if (noData) continue;
+
+		if (event.size > sizeof (MidiMessage::buffer)) {
+			// TODO: should not printf in RT callback:
+			fwprintf(stderr, L"Error: MIDI message was too large → skipping event. Maximum allowed size: %lu bytes.\n", sizeof (MidiMessage::buffer));
+		} else if (jack_ringbuffer_write_space(ringBuffer) >= sizeof (MidiMessage)) {
+			MidiMessage m;
+			m.time = event.time;
+			m.size = event.size;
+			memcpy(m.buffer, event.buffer, event.size);
+			jack_ringbuffer_write(ringBuffer, (const char *) &m, sizeof (MidiMessage));
+		} else {
+			// TODO: should not printf in RT callback:
+			fwprintf(stderr, L"Error: ring buffer is full → skipping event.\n");
+		}
+	}
+
+	// TODO: just count skipped events and bytes and report them in next successful message instead of printing to STDERR
+
+	if (pthread_mutex_trylock(&messageThreadLock) == 0) {
+		pthread_cond_signal(&dataReady);
+		pthread_mutex_unlock(&messageThreadLock);
+	}
+
+	return 0;
+}
+
+static void writeRecord(std::shared_ptr<RelationalWriter> writer,
+		string_t eventType, integer_t channel,
+		boolean_t noteOn, integer_t pitch, integer_t velocity,
+		integer_t controllerId, integer_t value) {
+	writer->writeAttribute(eventType);
+	writer->writeAttribute(&channel, typeid (channel));
+	writer->writeAttribute(&noteOn, typeid (noteOn));
+	writer->writeAttribute(&pitch, typeid (pitch));
+	writer->writeAttribute(&velocity, typeid (velocity));
+	writer->writeAttribute(&controllerId, typeid (controllerId));
+	writer->writeAttribute(&value, typeid (value));
+}
+
+static void processMessage(std::shared_ptr<RelationalWriter> writer, MidiMessage* event) {
+	if (event->size == 0) {
+		return;
+	} else {
+		uint8_t type = event->buffer[0] & 0xF0;
+		uint8_t channel = event->buffer[0] & 0x0F;
+
+		// TODO: write timestamp, message number
+		// TODO: write raw buffer in hex
+
+		if ((type == 0x90 || type == 0x80) && event->size == 3) {
+			writeRecord(writer, L"note", channel, type == 0x90, event->buffer[1], event->buffer[2], 0, 0);
+		} else if (type == 0xB0 && event->size == 3) {
+			writeRecord(writer, L"control", channel, false, 0, 0, event->buffer[1], event->buffer[2]);
+		}
+	}
+}
+
+static void finish(int sig) {
+	continueProcessing = false;
+}
+
+void processJackStream(ostream &output) {
+	// Relation headers:
+	std::shared_ptr<RelationalWriter> writer(Factory::create(output));
+	vector<AttributeMetadata> metadata;
+	metadata.push_back({L"event", TypeId::STRING});
+	metadata.push_back({L"channel", TypeId::INTEGER});
+	metadata.push_back({L"note_on", TypeId::BOOLEAN});
+	metadata.push_back({L"note_pitch", TypeId::INTEGER});
+	metadata.push_back({L"note_velocity", TypeId::INTEGER});
+	metadata.push_back({L"controller_id", TypeId::INTEGER});
+	metadata.push_back({L"controller_value", TypeId::INTEGER});
+	writer->startRelation(L"midi", metadata, true);
+	output.flush();
+
+	// Initialize JACK connection:
+	std::string clientName = "relpipe-in-jack";
+	jack_client_t* client = jack_client_open(clientName.c_str(), JackNullOption, nullptr);
+	if (client == nullptr) throw JackException(L"Could not create JACK client.");
+
+	ringBuffer = jack_ringbuffer_create(RING_BUFFER_SIZE * sizeof (MidiMessage));
+
+	jack_set_process_callback(client, enqueueMessage, nullptr);
+	// TODO: report also other events (connections etc.)
+
+	jackPort = jack_port_register(client, "input", JACK_DEFAULT_MIDI_TYPE, JackPortIsInput, 0);
+	if (jackPort == nullptr) throw JackException(L"Could not register port.");
+
+	if (mlockall(MCL_CURRENT | MCL_FUTURE)) fwprintf(stderr, L"Warning: Can not lock memory.\n");
+
+	int jackError = jack_activate(client);
+	if (jackError) throw JackException(L"Could not activate client.");
+
+	signal(SIGHUP, finish);
+	signal(SIGINT, finish);
+
+
+	// Process messages from the ring buffer queue:
+	pthread_mutex_lock(&messageThreadLock);
+	while (continueProcessing) {
+		const size_t queuedMessages = jack_ringbuffer_read_space(ringBuffer) / sizeof (MidiMessage);
+		for (size_t i = 0; i < queuedMessages; ++i) {
+			MidiMessage m;
+			jack_ringbuffer_read(ringBuffer, (char*) &m, sizeof (MidiMessage));
+			processMessage(writer, &m);
+			output.flush();
+		}
+		pthread_cond_wait(&dataReady, &messageThreadLock);
+	}
+	pthread_mutex_unlock(&messageThreadLock);
+
+	// Close JACK connection:
+	jack_deactivate(client);
+	jack_client_close(client);
+	jack_ringbuffer_free(ringBuffer);
+}
+
+int main(int argc, char** argv) {
+	setlocale(LC_ALL, "");
+	CLI::untieStdIO();
+	CLI cli(argc, argv);
+	// TODO: options, CLI parsing, configurable attributes
+	// TODO: separate handler class
+
+	int resultCode = CLI::EXIT_CODE_UNEXPECTED_ERROR;
+
+	try {
+		processJackStream(cout);
+		resultCode = CLI::EXIT_CODE_SUCCESS;
+	} catch (JackException e) {
+		fwprintf(stderr, L"Caught JACK exception: %ls\n", e.getMessge().c_str());
+		fwprintf(stderr, L"Debug: Input stream: eof=%ls, lastRead=%d\n", (cin.eof() ? L"true" : L"false"), cin.gcount());
+		resultCode = CLI::EXIT_CODE_UNEXPECTED_ERROR;
+	} catch (RelpipeWriterException e) {
+		fwprintf(stderr, L"Caught Writer exception: %ls\n", e.getMessge().c_str());
+		fwprintf(stderr, L"Debug: Input stream: eof=%ls, lastRead=%d\n", (cin.eof() ? L"true" : L"false"), cin.gcount());
+		resultCode = CLI::EXIT_CODE_DATA_ERROR;
+	}
+
+	return resultCode;
+}