jack: add jack source and sink

Makes a device with a source and sink that automatically
proxies all physical ports from jack. Jack then drives our
PipeWire pipeline from its own thread.

spa/plugins/jack/jack-client.c

@@ -0,0 +1,106 @@
+/* Spa JACK Client
+ *
+ * Copyright © 2019 Wim Taymans
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <errno.h>
+
+#include "jack-client.h"
+
+static int jack_process(jack_nframes_t nframes, void *arg)
+{
+	struct spa_jack_client *client = arg;
+
+	client->buffer_size = nframes;
+	spa_jack_client_emit_process(client);
+
+	return 0;
+}
+
+static void jack_shutdown(void* arg)
+{
+	struct spa_jack_client *client = arg;
+
+	spa_jack_client_emit_shutdown(client);
+}
+
+static int jack_buffer_size(jack_nframes_t nframes, void *arg)
+{
+	return 0;
+}
+
+
+static int status_to_result(jack_status_t status)
+{
+	int res;
+
+	if (status & JackInvalidOption)
+		res = -EINVAL;
+	else if (status & JackServerFailed)
+		res = -ECONNREFUSED;
+	else if (status & JackVersionError)
+		res = -EPROTO;
+	else
+		res = -EFAULT;
+
+	return res;
+}
+
+int spa_jack_client_open(struct spa_jack_client *client,
+		const char *client_name, const char *server_name)
+{
+	jack_status_t status;
+
+	if (client->client)
+		return 0;
+
+	client->client = jack_client_open(client_name,
+			JackNoStartServer, &status, NULL);
+
+	if (client->client == NULL)
+		return status_to_result(status);
+
+	spa_hook_list_init(&client->listener_list);
+
+	jack_set_process_callback(client->client, jack_process, client);
+	jack_on_shutdown(client->client, jack_shutdown, client);
+	jack_set_buffer_size_callback(client->client, jack_buffer_size, client);
+
+	return 0;
+}
+
+
+int spa_jack_client_close(struct spa_jack_client *client)
+{
+	if (client->client == NULL)
+		return 0;
+
+	spa_jack_client_emit_destroy(client);
+
+	if (jack_client_close(client->client) != 0)
+		return -EIO;
+
+	spa_hook_list_init(&client->listener_list);
+	client->client = NULL;
+
+	return 0;
+}