add and use Source::empty() since it can be done more efficiently than length(pos) == 0

git-svn-id: svn://localhost/ardour2/branches/3.0@7300 d708f5d6-7413-0410-9779-e7cbd77b26cf

7 files changed, 28 insertions, 13 deletions

diff --git a/libs/ardour/ardour/audiosource.h b/libs/ardour/ardour/audiosource.h
index fa9e3439c1..2d749dd673 100644
--- a/libs/ardour/ardour/audiosource.h
+++ b/libs/ardour/ardour/audiosource.h
@@ -50,6 +50,7 @@ class AudioSource : virtual public Source,
 	framecnt_t readable_length() const { return _length; }
 	uint32_t   n_channels()      const { return 1; }
 
+        bool       empty() const;
 	framecnt_t length (framepos_t pos) const;
 	void      update_length (framepos_t pos, framecnt_t cnt);
 
diff --git a/libs/ardour/ardour/midi_source.h b/libs/ardour/ardour/midi_source.h
index c418559d6e..36c8548e20 100644
--- a/libs/ardour/ardour/midi_source.h
+++ b/libs/ardour/ardour/midi_source.h
@@ -74,8 +74,9 @@ class MidiSource : virtual public Source
 	virtual void append_event_unlocked_frames(const Evoral::Event<nframes_t>& ev,
 			sframes_t source_start) = 0;
 
-	virtual sframes_t length (sframes_t pos) const;
-	virtual void      update_length (sframes_t pos, sframes_t cnt);
+	virtual bool       empty () const;
+	virtual framecnt_t length (framepos_t pos) const;
+	virtual void       update_length (framepos_t pos, framecnt_t cnt);
 
 	virtual void mark_streaming_midi_write_started (NoteMode mode, sframes_t start_time);
 	virtual void mark_streaming_write_started ();
diff --git a/libs/ardour/ardour/source.h b/libs/ardour/ardour/source.h
index 3ee1e609fc..9abf7ff8f0 100644
--- a/libs/ardour/ardour/source.h
+++ b/libs/ardour/ardour/source.h
@@ -60,6 +60,7 @@ class Source : public SessionObject
 	time_t timestamp() const { return _timestamp; }
 	void stamp (time_t when) { _timestamp = when; }
 
+	virtual bool       empty () const = 0;
 	virtual framecnt_t length (framepos_t pos) const = 0;
 	virtual void       update_length (framepos_t pos, framecnt_t cnt) = 0;
 
diff --git a/libs/ardour/audiosource.cc b/libs/ardour/audiosource.cc
index d864030646..a25e24ab7a 100644
--- a/libs/ardour/audiosource.cc
+++ b/libs/ardour/audiosource.cc
@@ -126,14 +126,20 @@ AudioSource::set_state (const XMLNode& node, int /*version*/)
 	return 0;
 }
 
-sframes_t
-AudioSource::length (sframes_t /*pos*/) const
+bool
+AudioSource::empty () const
+{
+        return _length == 0;
+}
+
+framecnt_t
+AudioSource::length (framepos_t /*pos*/) const
 {
 	return _length;
 }
 
 void
-AudioSource::update_length (sframes_t pos, sframes_t cnt)
+AudioSource::update_length (framepos_t pos, framecnt_t cnt)
 {
 	if (pos + cnt > _length) {
 		_length = pos + cnt;
diff --git a/libs/ardour/file_source.cc b/libs/ardour/file_source.cc
index c00e3ddbc3..fd66a7a167 100644
--- a/libs/ardour/file_source.cc
+++ b/libs/ardour/file_source.cc
@@ -82,7 +82,7 @@ FileSource::removable () const
 {
 	return (_flags & Removable)
 		&& ((_flags & RemoveAtDestroy) || 
-		    ((_flags & RemovableIfEmpty) && length(timeline_position()) == 0));
+		    ((_flags & RemovableIfEmpty) && empty() == 0));
 }
 
 int
diff --git a/libs/ardour/midi_source.cc b/libs/ardour/midi_source.cc
index 54b287cbdf..94c1a9b811 100644
--- a/libs/ardour/midi_source.cc
+++ b/libs/ardour/midi_source.cc
@@ -112,9 +112,19 @@ MidiSource::set_state (const XMLNode& node, int /*version*/)
 	return 0;
 }
 
-sframes_t
-MidiSource::length (sframes_t pos) const
+bool
+MidiSource::empty () const
 {
+        return _length_beats == 0;
+}
+
+framecnt_t
+MidiSource::length (framepos_t pos) const
+{
+        if (_length_beats == 0) {
+                return 0;
+        }
+
 	BeatsFramesConverter converter(_session.tempo_map(), pos);
 	return converter.to(_length_beats);
 }
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index f26933d875..c94fa7b976 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -1044,14 +1044,10 @@ Session::state(bool full_state)
                            and unused by any regions.
                         */
 
-                        cerr << "Source " << siter->second->name() << " has UC = " << siter->second->used() 
-                             << " length = " <<  siter->second->length (0)
-                             << endl;
-
 			boost::shared_ptr<FileSource> fs;
 			if ((fs = boost::dynamic_pointer_cast<FileSource> (siter->second)) != 0) {
 				if (!fs->destructive()) {
-					if (fs->length(fs->timeline_position()) == 0 && !fs->used()) {
+					if (fs->empty() && !fs->used()) {
 						continue;
 					}
 				}