Give Processor::run a new parameter to say whether or not the run method must leave

the passed-in buffers valid.  In the case where the main outs delivery is the last
processor in a route, this is not necessary (and wasteful).  If another processor
(e.g. a meter) follows the main outs, the passed-in (scratch) buffers must be valid
or the meter will get garbage data.

Fixes meters displaying phantom signals in some cases.


git-svn-id: svn://localhost/ardour2/branches/3.0@6180 d708f5d6-7413-0410-9779-e7cbd77b26cf

10 files changed, 13 insertions, 10 deletions

diff --git a/libs/ardour/ardour/amp.h b/libs/ardour/ardour/amp.h
index 724b1095a1..c237479abd 100644
--- a/libs/ardour/ardour/amp.h
+++ b/libs/ardour/ardour/amp.h
@@ -44,7 +44,7 @@ public:
 	bool can_support_io_configuration (const ChanCount& in, ChanCount& out) const;
 	bool configure_io (ChanCount in, ChanCount out);
 
-	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes);
+	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes, bool);
 
 	bool apply_gain() const  { return _apply_gain; }
 	void apply_gain(bool yn) { _apply_gain = yn; }
diff --git a/libs/ardour/ardour/delivery.h b/libs/ardour/ardour/delivery.h
index add222a0f1..1b1a217466 100644
--- a/libs/ardour/ardour/delivery.h
+++ b/libs/ardour/ardour/delivery.h
@@ -65,7 +65,7 @@ public:
 	bool can_support_io_configuration (const ChanCount& in, ChanCount& out) const;
 	bool configure_io (ChanCount in, ChanCount out);
 
-	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes);
+	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes, bool);
 
 	/* supplemental method used with MIDI */
 
diff --git a/libs/ardour/ardour/internal_return.h b/libs/ardour/ardour/internal_return.h
index dfd37a4de5..205559fe4e 100644
--- a/libs/ardour/ardour/internal_return.h
+++ b/libs/ardour/ardour/internal_return.h
@@ -40,7 +40,7 @@ class InternalReturn : public Return
 	XMLNode& get_state(void);
 	int set_state(const XMLNode&, int version);
 
-	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes);
+	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes, bool);
 	bool configure_io (ChanCount in, ChanCount out);
 	bool can_support_io_configuration (const ChanCount& in, ChanCount& out) const;
 	void set_block_size (nframes_t);
diff --git a/libs/ardour/ardour/internal_send.h b/libs/ardour/ardour/internal_send.h
index 245a136dc8..ac184a69bf 100644
--- a/libs/ardour/ardour/internal_send.h
+++ b/libs/ardour/ardour/internal_send.h
@@ -40,7 +40,7 @@ class InternalSend : public Send
 	XMLNode& get_state(void);
 	int set_state(const XMLNode& node, int version);
 	
-	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes);
+	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes, bool);
 	bool feeds (boost::shared_ptr<Route> other) const;
 	bool can_support_io_configuration (const ChanCount& in, ChanCount& out) const;
 	bool configure_io (ChanCount in, ChanCount out);
diff --git a/libs/ardour/ardour/meter.h b/libs/ardour/ardour/meter.h
index 10272ee733..e0b956c0f9 100644
--- a/libs/ardour/ardour/meter.h
+++ b/libs/ardour/ardour/meter.h
@@ -61,7 +61,7 @@ public:
 	bool configure_io (ChanCount in, ChanCount out);
 
 	/** Compute peaks */
-	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes);
+	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes, bool);
 
 	float peak_power (uint32_t n) {
 		if (n < _visible_peak_power.size()) {
diff --git a/libs/ardour/ardour/plugin_insert.h b/libs/ardour/ardour/plugin_insert.h
index 348cda218e..593db1ff0d 100644
--- a/libs/ardour/ardour/plugin_insert.h
+++ b/libs/ardour/ardour/plugin_insert.h
@@ -54,7 +54,7 @@ class PluginInsert : public Processor
 	XMLNode& get_state(void);
 	int set_state(const XMLNode&, int version);
 
-	void run (BufferSet& in, sframes_t start_frame, sframes_t end_frame, nframes_t nframes);
+	void run (BufferSet& in, sframes_t start_frame, sframes_t end_frame, nframes_t nframes, bool);
 	void silence (nframes_t nframes);
 
 	void activate ();
diff --git a/libs/ardour/ardour/port_insert.h b/libs/ardour/ardour/port_insert.h
index 3283415e6d..f013a6a442 100644
--- a/libs/ardour/ardour/port_insert.h
+++ b/libs/ardour/ardour/port_insert.h
@@ -51,7 +51,7 @@ class PortInsert : public IOProcessor
 	XMLNode& get_state(void);
 	int set_state (const XMLNode&, int version);
 
-	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes);
+	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes, bool);
 
 	nframes_t signal_latency() const;
 
diff --git a/libs/ardour/ardour/processor.h b/libs/ardour/ardour/processor.h
index 3ec4a9885d..c57eb4354c 100644
--- a/libs/ardour/ardour/processor.h
+++ b/libs/ardour/ardour/processor.h
@@ -70,7 +70,10 @@ class Processor : public SessionObject, public AutomatableControls, public Laten
 
 	virtual void set_block_size (nframes_t /*nframes*/) {}
 
-	virtual void run (BufferSet& /*bufs*/, sframes_t /*start_frame*/, sframes_t /*end_frame*/, nframes_t /*nframes*/) {}
+	/** @param result_required true if, on return from this method, bufs is required to contain valid data;
+	 *  if false, the method need not bother writing to bufs if it doesn't want to.
+	 */  
+	virtual void run (BufferSet& /*bufs*/, sframes_t /*start_frame*/, sframes_t /*end_frame*/, nframes_t /*nframes*/, bool /*result_required*/) {}
 	virtual void silence (nframes_t /*nframes*/) {}
 
 	virtual void activate ()   { _pending_active = true; ActiveChanged(); }
diff --git a/libs/ardour/ardour/return.h b/libs/ardour/ardour/return.h
index b3212fe4a0..a3d3859899 100644
--- a/libs/ardour/ardour/return.h
+++ b/libs/ardour/ardour/return.h
@@ -44,7 +44,7 @@ public:
 
 	uint32_t bit_slot() const { return _bitslot; }
 
-	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes);
+	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes, bool);
 
 	boost::shared_ptr<Amp> amp() const { return _amp; }
 	boost::shared_ptr<PeakMeter> meter() const { return _meter; }
diff --git a/libs/ardour/ardour/send.h b/libs/ardour/ardour/send.h
index b86d321bd2..78a82820df 100644
--- a/libs/ardour/ardour/send.h
+++ b/libs/ardour/ardour/send.h
@@ -57,7 +57,7 @@ class Send : public Delivery
 
 	uint32_t pans_required() const { return _configured_input.n_audio(); }
 
-	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes);
+	void run (BufferSet& bufs, sframes_t start_frame, sframes_t end_frame, nframes_t nframes, bool);
 
 	bool can_support_io_configuration (const ChanCount& in, ChanCount& out) const;
 	bool configure_io (ChanCount in, ChanCount out);