Fix graph ordering incl. Inserts, Returns and SideChains

When building the process graph. Ardour usess
   Route::direct_feeds_according_to_reality()
This function only tests if the current route (or any ioprocessors)
is feeding another route's *input*.

Inserts, Return and now Sidechains are ignored as destinations on the
destination route are not taken into account.

This is now resolved by adding an IOVector, a collection of all inputs
of the destination route.

libs/ardour/ardour/io_vector.h

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2016 Robin Gareus <robin@gareus.org>
+ * Copyright (C) 2006 Paul Davis
+ *
+ * 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 2
+ * of the License, or (at your option) 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#ifndef __ardour_io_vector_h__
+#define __ardour_io_vector_h__
+
+#include <vector>
+#include <boost/shared_ptr.hpp>
+#include "ardour/io.h"
+
+namespace ARDOUR {
+
+class IOVector : public std::vector<boost::weak_ptr<ARDOUR::IO> >
+{
+public:
+	bool connected_to (const IOVector& other) const {
+		for (IOVector::const_iterator i = other.begin(); i != other.end(); ++i) {
+			boost::shared_ptr<const IO> io = i->lock();
+			if (!io) continue;
+			if (connected_to (io)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	bool connected_to (boost::shared_ptr<const IO> other) const {
+		for (IOVector::const_iterator i = begin(); i != end(); ++i) {
+			boost::shared_ptr<const IO> io = i->lock();
+			if (!io) continue;
+			if (io->connected_to (other)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	bool fed_by (boost::shared_ptr<const IO> other) const {
+		for (IOVector::const_iterator i = begin(); i != end(); ++i) {
+			boost::shared_ptr<const IO> io = i->lock();
+			if (!io) continue;
+			if (other->connected_to (io)) {
+				return true;
+			}
+		}
+		return false;
+	}
+};
+
+} // namespace ARDOUR
+
+
+#endif

libs/ardour/ardour/route.h

@@ -44,6 +44,7 @@
 #include "ardour/gain_control.h"
 #include "ardour/instrument_info.h"
 #include "ardour/io.h"
+#include "ardour/io_vector.h"
 #include "ardour/libardour_visibility.h"
 #include "ardour/types.h"
 #include "ardour/mute_master.h"
@@ -89,6 +90,7 @@ class LIBARDOUR_API Route : public SessionObject, public Automatable, public Rou
 
 	boost::shared_ptr<IO> input() const { return _input; }
 	boost::shared_ptr<IO> output() const { return _output; }
+	IOVector all_inputs () const;
 
 	ChanCount n_inputs() const { return _input->n_ports(); }
 	ChanCount n_outputs() const { return _output->n_ports(); }

libs/ardour/route.cc

@@ -3601,12 +3601,43 @@ Route::feeds (boost::shared_ptr<Route> other, bool* via_sends_only)
 	return false;
 }
 
+IOVector
+Route::all_inputs () const
+{
+	/* TODO, if this works as expected,
+	 * cache the IOVector and maintain it via
+	 * input_change_handler(), sidechain_change_handler() etc
+	 */
+	IOVector ios;
+	ios.push_back (_input);
+
+	Glib::Threads::RWLock::ReaderLock lm (_processor_lock);
+	for (ProcessorList::const_iterator r = _processors.begin(); r != _processors.end(); ++r) {
+
+		boost::shared_ptr<IOProcessor> iop = boost::dynamic_pointer_cast<IOProcessor>(*r);
+		boost::shared_ptr<PluginInsert> pi = boost::dynamic_pointer_cast<PluginInsert>(*r);
+		if (pi != 0) {
+			assert (iop == 0);
+			iop = pi->sidechain();
+		}
+
+		if (iop != 0 && iop->input()) {
+		ios.push_back (iop->input());
+		}
+	}
+	return ios;
+}
+
 bool
 Route::direct_feeds_according_to_reality (boost::shared_ptr<Route> other, bool* via_send_only)
 {
 	DEBUG_TRACE (DEBUG::Graph, string_compose ("Feeds? %1\n", _name));
-
-	if (_output->connected_to (other->input())) {
+#if 0
+	if (_output->connected_to (other->input()))
+#else
+		if (other->all_inputs().fed_by (_output))
+#endif
+	{
 		DEBUG_TRACE (DEBUG::Graph, string_compose ("\tdirect FEEDS %2\n", other->name()));
 		if (via_send_only) {
 			*via_send_only = false;
@@ -3616,6 +3647,7 @@ Route::direct_feeds_according_to_reality (boost::shared_ptr<Route> other, bool*
 	}
 
 
+	Glib::Threads::RWLock::ReaderLock lm (_processor_lock); // XXX
 	for (ProcessorList::iterator r = _processors.begin(); r != _processors.end(); ++r) {
 
 		boost::shared_ptr<IOProcessor> iop = boost::dynamic_pointer_cast<IOProcessor>(*r);
@@ -3626,7 +3658,13 @@ Route::direct_feeds_according_to_reality (boost::shared_ptr<Route> other, bool*
 		}
 
 		if (iop != 0) {
-			if (iop->feeds (other)) {
+#if 0
+			if (iop->feeds (other))
+#else
+			boost::shared_ptr<const IO> iop_out = iop->output();
+			if (iop_out && other->all_inputs().fed_by (iop_out))
+#endif
+			{
 				DEBUG_TRACE (DEBUG::Graph,  string_compose ("\tIOP %1 does feed %2\n", iop->name(), other->name()));
 				if (via_send_only) {
 					*via_send_only = true;