add new template methods for "foreach {route,track}" and use them

Also remove redundant double call to Track::set_block_size(). This dates back to 2010
when there used be an additional traversal of the Diskstream RCU-managed list, before
they became owned by Tracks

libs/ardour/ardour/session.h

@@ -350,6 +350,12 @@ public:
 	template<class T> void foreach_route (T *obj, void (T::*func)(boost::shared_ptr<Route>), bool sort = true);
 	template<class T, class A> void foreach_route (T *obj, void (T::*func)(Route&, A), A arg, bool sort = true);
 
+	template<class A>            void foreach_track (void (Track::*method)(A), A arg);
+	template<class A1, class A2> void foreach_track (void (Track::*method)(A1, A2), A1 arg1, A2 arg2);
+
+	template<class A>            void foreach_route (void (Route::*method)(A), A arg);
+	template<class A1, class A2> void foreach_route (void (Route::*method)(A1, A2), A1 arg1, A2 arg2);
+
 	static char session_name_is_legal (const std::string&);
 	bool io_name_is_legal (const std::string&) const;
 	boost::shared_ptr<Route> route_by_name (std::string) const;

libs/ardour/ardour/session_route.h

@@ -76,6 +76,53 @@ Session::foreach_route (T *obj, void (T::*func)(Route&, A), A arg1, bool sort)
 	}
 }
 
+
+template<class A> void
+Session::foreach_track (void (Track::*method)(A), A arg)
+{
+	boost::shared_ptr<RouteList> r = routes.reader();
+
+	for (RouteList::iterator i = r->begin(); i != r->end(); i++) {
+		boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+		if (tr) {
+			(tr->*method) (arg);
+		}
+	}
+}
+
+template<class A1, class A2> void
+Session::foreach_track (void (Track::*method)(A1, A2), A1 arg1, A2 arg2)
+{
+	boost::shared_ptr<RouteList> r = routes.reader();
+
+	for (RouteList::iterator i = r->begin(); i != r->end(); i++) {
+		boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
+		if (tr) {
+			(tr->*method) (arg1, arg2);
+		}
+	}
+}
+
+template<class A> void
+Session::foreach_route (void (Route::*method)(A), A arg)
+{
+	boost::shared_ptr<RouteList> r = routes.reader();
+
+	for (RouteList::iterator i = r->begin(); i != r->end(); i++) {
+		((*i).get()->*method) (arg);
+	}
+}
+
+template<class A1, class A2> void
+Session::foreach_route (void (Route::*method)(A1, A2), A1 arg1, A2 arg2)
+{
+	boost::shared_ptr<RouteList> r = routes.reader();
+
+	for (RouteList::iterator i = r->begin(); i != r->end(); i++) {
+		((*i).get()->*method) (arg1, arg2);
+	}
+}
+
 } /* namespace */
 
 #endif /* __ardour_session_route_h__ */

libs/ardour/session.cc

@@ -109,6 +109,7 @@
 #include "ardour/session.h"
 #include "ardour/session_directory.h"
 #include "ardour/session_playlists.h"
+#include "ardour/session_route.h"
 #include "ardour/smf_source.h"
 #include "ardour/solo_isolate_control.h"
 #include "ardour/source_factory.h"
@@ -2080,19 +2081,7 @@ Session::set_block_size (pframes_t nframes)
 
 	ensure_buffers ();
 
-	boost::shared_ptr<RouteList> r = routes.reader ();
-
-	for (RouteList::iterator i = r->begin(); i != r->end(); ++i) {
-		(*i)->set_block_size (nframes);
-	}
-
-	boost::shared_ptr<RouteList> rl = routes.reader ();
-	for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
-		boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
-		if (tr) {
-			tr->set_block_size (nframes);
-		}
-	}
+	foreach_route (&Route::set_block_size, nframes);
 
 	DEBUG_TRACE (DEBUG::LatencyCompensation, "Session::set_block_size -> update worst i/o latency\n");
 	/* when this is called from the auto-connect thread, the process-lock is held */

libs/ardour/session_butler.cc

@@ -107,13 +107,7 @@ Session::overwrite_some_buffers (boost::shared_ptr<Route> r, OverwriteReason why
 
 	} else {
 
-		boost::shared_ptr<RouteList> rl = routes.reader();
-		for (RouteList::iterator i = rl->begin(); i != rl->end(); ++i) {
-			boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (*i);
-			if (tr) {
-				tr->set_pending_overwrite (why);
-			}
-		}
+		foreach_track (&Track::set_pending_overwrite, why);
 	}
 
 	add_post_transport_work (PostTransportOverWrite);