loopback_internal: add new node-type for internal loopback

include/villas/node_type.h

@@ -43,7 +43,8 @@ class SuperNode;
 }
 
 enum class NodeFlags {
-	PROVIDES_SIGNALS	= (1 << 0)
+	PROVIDES_SIGNALS	= (1 << 0),
+	INTERNAL		= (1 << 1)
 };
 
 /** C++ like vtable construct for node_types */

include/villas/nodes/loopback_internal.hpp

@@ -0,0 +1,67 @@
+/** Node-type for internal loopback connections.
+ *
+ * @file
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLASnode
+ *
+ * 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, either version 3 of the License, or
+ * any later version.
+ *
+ * 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/>.
+ *********************************************************************************/
+
+/**
+ * @ingroup node
+ * @addtogroup loopback Loopback connections
+ * @{
+ */
+
+#pragma once
+
+#include <villas/queue_signalled.h>
+#include <villas/pool.h>
+
+/* Forward declarations */
+struct vnode;
+struct sample;
+
+/** Node-type for signal generation.
+ * @see node_type
+ */
+struct loopback_internal {
+	int queuelen;
+	enum QueueSignalledMode mode;
+	struct queue_signalled queue;
+
+	struct vnode *source;
+};
+
+/** @see node_type::print */
+char * loopback_internal_print(struct vnode *n);
+
+/** @see node_type::start */
+int loopback_internal_start(struct vnode *n);
+
+/** @see node_type::stop */
+int loopback_internal_stop(struct vnode *n);
+
+/** @see node_type::read */
+int loopback_internal_read(struct vnode *n, struct sample *smps[], unsigned cnt, unsigned *release);
+
+/** @see node_type::write */
+int loopback_internal_write(struct vnode *n, struct sample *smps[], unsigned cnt, unsigned *release);
+
+struct vnode * loopback_internal_create(struct vnode *orig);
+
+/** @} */

lib/nodes/CMakeLists.txt

@@ -20,7 +20,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ###################################################################################
 
-set(NODE_SRC)
+set(NODE_SRC
+	loopback_internal.cpp
+)
 
 if(LIBNL3_ROUTE_FOUND)
     list(APPEND LIBRARIES PkgConfig::LIBNL3_ROUTE)

lib/nodes/loopback_internal.cpp

@@ -0,0 +1,158 @@
+/** Node-type for internal loopback_internal connections.
+ *
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLASnode
+ *
+ * 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, either version 3 of the License, or
+ * any later version.
+ *
+ * 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 <cstring>
+
+#include <villas/node.h>
+#include <villas/plugin.h>
+#include <villas/node/config.h>
+#include <villas/nodes/loopback_internal.hpp>
+#include <villas/exceptions.hpp>
+#include <villas/memory.h>
+
+using namespace villas;
+using namespace villas::utils;
+
+static struct plugin p;
+
+int loopback_internal_init(struct vnode *n)
+{
+	struct loopback_internal *l = (struct loopback_internal *) n->_vd;
+
+	l->mode = QueueSignalledMode::EVENTFD;
+	l->queuelen = DEFAULT_QUEUE_LENGTH;
+
+	return 0;
+}
+
+int loopback_internal_prepare(struct vnode *n)
+{
+	struct loopback_internal *l = (struct loopback_internal *) n->_vd;
+
+	return queue_signalled_init(&l->queue, l->queuelen, memory_default, QueueSignalledMode::EVENTFD);
+}
+
+int loopback_internal_destroy(struct vnode *n)
+{
+	struct loopback_internal *l= (struct loopback_internal *) n->_vd;
+
+	return queue_signalled_destroy(&l->queue);
+}
+
+int loopback_internal_read(struct vnode *n, struct sample *smps[], unsigned cnt, unsigned *release)
+{
+	int avail;
+
+	struct loopback_internal *l = (struct loopback_internal *) n->_vd;
+	struct sample *cpys[cnt];
+
+	avail = queue_signalled_pull_many(&l->queue, (void **) cpys, cnt);
+
+	for (int i = 0; i < avail; i++) {
+		sample_copy(smps[i], cpys[i]);
+		sample_decref(cpys[i]);
+	}
+
+	return avail;
+}
+
+int loopback_internal_write(struct vnode *n, struct sample *smps[], unsigned cnt, unsigned *release)
+{
+	struct loopback_internal *l = (struct loopback_internal *) n->_vd;
+
+	sample_incref_many(smps, cnt);
+
+	return queue_signalled_push_many(&l->queue, (void **) smps, cnt);
+}
+
+char * loopback_internal_print(struct vnode *n)
+{
+	struct loopback_internal *l = (struct loopback_internal *) n->_vd;
+	char *buf = nullptr;
+
+	strcatf(&buf, "queuelen=%d", l->queuelen);
+
+	return buf;
+}
+
+int loopback_internal_poll_fds(struct vnode *n, int fds[])
+{
+	struct loopback_internal *l = (struct loopback_internal *) n->_vd;
+
+	fds[0] = queue_signalled_fd(&l->queue);
+
+	return 1;
+}
+
+struct vnode * loopback_internal_create(struct vnode *orig)
+{
+	int ret;
+	struct vnode *n;
+	struct loopback_internal *l;
+	
+	n = new struct vnode;
+	if (!n)
+		throw MemoryAllocationError();
+
+	l = (struct loopback_internal *) n->_vd;
+
+	ret = node_init(n, &p.node);
+	if (ret)
+		return nullptr;
+
+	l->source = orig;
+
+	asprintf(&n->name, "%s_lo%zu", node_name_short(orig), vlist_length(&orig->sources));
+
+	ret = signal_list_copy(&n->in.signals, &orig->in.signals);
+	if (ret)
+		return nullptr;
+
+	return n;
+}
+
+__attribute__((constructor(110)))
+static void register_plugin() {
+	p.name			= "loopback_internal";
+	p.description		= "internal loopback to connect multiple paths";
+	p.type			= PluginType::NODE;
+	p.node.instances.state	= State::DESTROYED;
+	p.node.vectorize	= 0;
+	p.node.flags		= (int) NodeFlags::PROVIDES_SIGNALS | (int) NodeFlags::INTERNAL;
+	p.node.size		= sizeof(struct loopback_internal);
+	p.node.print		= loopback_internal_print;
+	p.node.prepare		= loopback_internal_prepare;
+	p.node.init		= loopback_internal_init;
+	p.node.destroy		= loopback_internal_destroy;
+	p.node.read		= loopback_internal_read;
+	p.node.write		= loopback_internal_write;
+	p.node.poll_fds		= loopback_internal_poll_fds;
+
+	int ret = vlist_init(&p.node.instances);
+	if (!ret)
+		vlist_init_and_push(&plugins, &p);
+}
+
+__attribute__((destructor(110)))
+static void deregister_plugin() {
+	vlist_remove_all(&plugins, &p);
+}