move all destructive functionality into SndFileSource as a mode, and drop DestructiveFileSource; make ardour save changes to destructive-xfade-msecs

git-svn-id: svn://localhost/ardour2/trunk@1065 d708f5d6-7413-0410-9779-e7cbd77b26cf

11 files changed, 487 insertions, 107 deletions

diff --git a/ardour.rc.in b/ardour.rc.in
index 735b19c233..61e7c976b9 100644
--- a/ardour.rc.in
+++ b/ardour.rc.in
@@ -1,4 +1,4 @@
-<?xml version="1.0"?>
+?xml version="1.0"?>
 <Ardour>
   <MIDI-port tag="%MIDITAG%" device="ardour" type="%MIDITYPE%" mode="duplex"/>
   <MIDI-port tag="control" device="ardour" type="%MIDITYPE%" mode="duplex"/>
@@ -31,6 +31,7 @@
     <Option name="quieten-at-speed" value="1.000000"/>
     <Option name="use-vst" value="yes"/>
     <Option name="use-tranzport" value="yes"/>
+    <Option name="destructive-xfade-msecs" value="500"/>
   </Config>
   <extra>
     <Keyboard edit-button="3" edit-modifier="4" delete-button="3" delete-modifier="1" snap-modifier="32"/>
diff --git a/gtk2_ardour/option_editor.cc b/gtk2_ardour/option_editor.cc
index 0f1be3dd21..8f50cfc975 100644
--- a/gtk2_ardour/option_editor.cc
+++ b/gtk2_ardour/option_editor.cc
@@ -318,9 +318,12 @@ OptionEditor::destructo_xfade_adjustment_changed ()
 	float val = destructo_xfade_adjustment.get_value();
 
 	/* val is in msecs */
+
 	
 	Config->set_destructive_xfade_msecs ((uint32_t) floor (val));
 
+	cerr << "set destructo fade to " << Config->get_destructive_xfade_msecs () << endl;
+
 	if (session) {
 		SndFileSource::setup_standard_crossfades (session->frame_rate());
 	} 
diff --git a/libs/ardour/SConscript b/libs/ardour/SConscript
index 06d53ac060..8c6bd36c2d 100644
--- a/libs/ardour/SConscript
+++ b/libs/ardour/SConscript
@@ -48,7 +48,6 @@ crossfade.cc
 curve.cc
 cycle_timer.cc
 default_click.cc
-destructive_filesource.cc
 gain.cc
 gdither.cc
 globals.cc
diff --git a/libs/ardour/ardour/audiofilesource.h b/libs/ardour/ardour/audiofilesource.h
index ac63941a8c..728432db81 100644
--- a/libs/ardour/ardour/audiofilesource.h
+++ b/libs/ardour/ardour/audiofilesource.h
@@ -95,6 +95,9 @@ class AudioFileSource : public AudioSource {
 	XMLNode& get_state ();
 	int set_state (const XMLNode&);
 
+	bool destructive() const { return (_flags & Destructive); }
+	virtual bool set_destructive (bool yn) { return false; }
+
 	/* this should really be protected, but C++ is getting stricter
 	   and creating slots from protected member functions is starting
 	   to cause issues.
diff --git a/libs/ardour/ardour/sndfilesource.h b/libs/ardour/ardour/sndfilesource.h
index 6302d88967..b810cb538b 100644
--- a/libs/ardour/ardour/sndfilesource.h
+++ b/libs/ardour/ardour/sndfilesource.h
@@ -36,10 +36,7 @@ class SndFileSource : public AudioFileSource {
 	/* constructor to be called for new in-session files */
 
 	SndFileSource (Session&, std::string path, SampleFormat samp_format, HeaderFormat hdr_format, nframes_t rate, 
-		       Flag flags = AudioFileSource::Flag (AudioFileSource::Writable|
-							   AudioFileSource::Removable|
-							   AudioFileSource::RemovableIfEmpty|
-							   AudioFileSource::CanRename));
+		       Flag flags = SndFileSource::default_writable_flags);
 		       
 	/* constructor to be called for existing in-session files */
 	
@@ -53,6 +50,16 @@ class SndFileSource : public AudioFileSource {
 
 	nframes_t natural_position () const;
 
+	nframes_t last_capture_start_frame() const;
+	void mark_capture_start (nframes_t);
+	void mark_capture_end ();
+	void clear_capture_marks();
+
+	bool set_destructive (bool yn);
+
+	static void setup_standard_crossfades (nframes_t sample_rate);
+	static const AudioFileSource::Flag default_writable_flags;
+
   protected:
 	void set_header_timeline_position ();
 
@@ -73,6 +80,24 @@ class SndFileSource : public AudioFileSource {
 	int open();
 	void close();
 	int setup_broadcast_info (nframes_t when, struct tm&, time_t);
+
+	/* destructive */
+
+	static nframes_t xfade_frames;
+	static gain_t* out_coefficient;
+	static gain_t* in_coefficient;
+
+	bool          _capture_start;
+	bool          _capture_end;
+	nframes_t      capture_start_frame;
+	nframes_t      file_pos; // unit is frames
+	Sample*        xfade_buf;
+
+	nframes_t crossfade (Sample* data, nframes_t cnt, int dir);
+	void set_timeline_position (nframes_t);
+	nframes_t destructive_write_unlocked (Sample *dst, nframes_t cnt);
+	nframes_t nondestructive_write_unlocked (Sample *dst, nframes_t cnt);
+	void handle_header_position_change ();
 };
 
 } // namespace ARDOUR
diff --git a/libs/ardour/audiofilesource.cc b/libs/ardour/audiofilesource.cc
index 8fe6c845c0..1fbde870a0 100644
--- a/libs/ardour/audiofilesource.cc
+++ b/libs/ardour/audiofilesource.cc
@@ -291,6 +291,11 @@ AudioFileSource::set_state (const XMLNode& node)
 		_is_embedded = false;
 	}
 
+	if ((prop = node.property (X_("destructive"))) != 0) {
+		/* old style, from the period when we had DestructiveFileSource */
+		_flags = Flag (_flags | Destructive);
+	}
+
 	return 0;
 }
 
diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index bbcbcae91f..2f0ae03f2d 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -313,7 +313,9 @@ AudioRegion::~AudioRegion ()
 bool
 AudioRegion::verify_length (nframes_t len)
 {
-	if (boost::dynamic_pointer_cast<DestructiveFileSource>(source())) {
+	boost::shared_ptr<AudioFileSource> afs = boost::dynamic_pointer_cast<AudioFileSource>(source());
+
+	if (afs && afs->destructive()) {
 		return true;
 	}
 
@@ -328,7 +330,9 @@ AudioRegion::verify_length (nframes_t len)
 bool
 AudioRegion::verify_start_and_length (nframes_t new_start, nframes_t new_length)
 {
-	if (boost::dynamic_pointer_cast<DestructiveFileSource>(source())) {
+	boost::shared_ptr<AudioFileSource> afs = boost::dynamic_pointer_cast<AudioFileSource>(source());
+
+	if (afs && afs->destructive()) {
 		return true;
 	}
 
@@ -342,7 +346,9 @@ AudioRegion::verify_start_and_length (nframes_t new_start, nframes_t new_length)
 bool
 AudioRegion::verify_start (nframes_t pos)
 {
-	if (boost::dynamic_pointer_cast<DestructiveFileSource>(source())) {
+	boost::shared_ptr<AudioFileSource> afs = boost::dynamic_pointer_cast<AudioFileSource>(source());
+
+	if (afs && afs->destructive()) {
 		return true;
 	}
 
@@ -357,7 +363,9 @@ AudioRegion::verify_start (nframes_t pos)
 bool
 AudioRegion::verify_start_mutable (nframes_t& new_start)
 {
-	if (boost::dynamic_pointer_cast<DestructiveFileSource>(source())) {
+	boost::shared_ptr<AudioFileSource> afs = boost::dynamic_pointer_cast<AudioFileSource>(source());
+
+	if (afs && afs->destructive()) {
 		return true;
 	}
 
@@ -1289,7 +1297,9 @@ AudioRegion::speed_mismatch (float sr) const
 void
 AudioRegion::source_offset_changed ()
 {
-	if (boost::dynamic_pointer_cast<DestructiveFileSource>(sources.front())) {
+	boost::shared_ptr<AudioFileSource> afs = boost::dynamic_pointer_cast<AudioFileSource>(sources.front());
+
+	if (afs && afs->destructive()) {
 		// set_start (source()->natural_position(), this);
 		set_position (source()->natural_position(), this);
 	} 
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 99fad0d013..d871f5a859 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -1325,7 +1325,7 @@ Session::set_frame_rate (nframes_t frames_per_second)
 	Route::set_automation_interval ((jack_nframes_t) ceil ((double) frames_per_second * 0.25));
 
 	// XXX we need some equivalent to this, somehow
-	// DestructiveFileSource::setup_standard_crossfades (frames_per_second);
+	// SndFileSource::setup_standard_crossfades (frames_per_second);
 
 	set_dirty();
 
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index d9c82f546b..603d3a5c2d 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -185,7 +185,7 @@ Session::first_stage_init (string fullpath, string snapshot_name)
 	/* default short fade = 15ms */
 
 	Crossfade::set_short_xfade_length ((nframes_t) floor (Config->get_short_xfade_seconds() * frame_rate()));
-	DestructiveFileSource::setup_standard_crossfades (frame_rate());
+	SndFileSource::setup_standard_crossfades (frame_rate());
 
 	last_mmc_step.tv_sec = 0;
 	last_mmc_step.tv_usec = 0;
@@ -838,13 +838,12 @@ Session::state(bool full_state)
 			boost::shared_ptr<AudioFileSource> fs;
 
 			if ((fs = boost::dynamic_pointer_cast<AudioFileSource> (siter->second)) != 0) {
-				boost::shared_ptr<DestructiveFileSource> dfs = boost::dynamic_pointer_cast<DestructiveFileSource> (fs);
 
 				/* destructive file sources are OK if they are empty, because
 				   we will re-use them every time.
 				*/
 
-				if (!dfs) {
+				if (!fs->destructive()) {
 					if (fs->length() == 0) {
 						continue;
 					}
diff --git a/libs/ardour/sndfilesource.cc b/libs/ardour/sndfilesource.cc
index cb4334c7cb..17e45c11d7 100644
--- a/libs/ardour/sndfilesource.cc
+++ b/libs/ardour/sndfilesource.cc
@@ -29,12 +29,22 @@
 
 #include <ardour/sndfilesource.h>
 
+#include <ardour/utils.h>
+
 #include "i18n.h"
 
 using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
+gain_t* SndFileSource::out_coefficient = 0;
+gain_t* SndFileSource::in_coefficient = 0;
+nframes_t SndFileSource::xfade_frames = 64;
+const AudioFileSource::Flag SndFileSource::default_writable_flags = AudioFileSource::Flag (AudioFileSource::Writable|
+											   AudioFileSource::Removable|
+											   AudioFileSource::RemovableIfEmpty|
+											   AudioFileSource::CanRename);
+
 SndFileSource::SndFileSource (Session& s, const XMLNode& node)
 	: AudioFileSource (s, node)
 {
@@ -195,6 +205,17 @@ SndFileSource::init (string idstr)
 	*/
 
 	memset (&_info, 0, sizeof(_info));
+
+	_capture_start = false;
+	_capture_end = false;
+	file_pos = 0;
+
+	if (destructive()) {
+		xfade_buf = new Sample[xfade_frames];
+		timeline_position = header_position_offset;
+	} 
+
+	AudioFileSource::HeaderPositionOffsetChanged.connect (mem_fun (*this, &SndFileSource::handle_header_position_change));
 }
 
 int
@@ -274,6 +295,10 @@ SndFileSource::~SndFileSource ()
 	if (_broadcast_info) {
 		delete _broadcast_info;
 	}
+
+	if (xfade_buf) {
+		delete [] xfade_buf;
+	}
 }
 
 float
@@ -360,6 +385,16 @@ SndFileSource::read_unlocked (Sample *dst, nframes_t start, nframes_t cnt) const
 nframes_t 
 SndFileSource::write_unlocked (Sample *data, nframes_t cnt)
 {
+	if (destructive()) {
+		return destructive_write_unlocked (data, cnt);
+	} else {
+		return nondestructive_write_unlocked (data, cnt);
+	}
+}
+
+nframes_t 
+SndFileSource::nondestructive_write_unlocked (Sample *data, nframes_t cnt)
+{
 	if (!writable()) {
 		return 0;
 	}
@@ -411,6 +446,117 @@ SndFileSource::write_unlocked (Sample *data, nframes_t cnt)
 	return cnt;
 }
 
+nframes_t
+SndFileSource::destructive_write_unlocked (Sample* data, nframes_t cnt)
+{
+	nframes_t old_file_pos;
+
+	if (!writable()) {
+		return 0;
+	}
+
+	if (_capture_start && _capture_end) {
+
+		/* start and end of capture both occur within the data we are writing,
+		   so do both crossfades.
+		*/
+
+		_capture_start = false;
+		_capture_end = false;
+		
+		/* move to the correct location place */
+		file_pos = capture_start_frame - timeline_position;
+		
+		// split cnt in half
+		nframes_t subcnt = cnt / 2;
+		nframes_t ofilepos = file_pos;
+		
+		// fade in
+		if (crossfade (data, subcnt, 1) != subcnt) {
+			return 0;
+		}
+		
+		file_pos += subcnt;
+		Sample * tmpdata = data + subcnt;
+		
+		// fade out
+		subcnt = cnt - subcnt;
+		if (crossfade (tmpdata, subcnt, 0) != subcnt) {
+			return 0;
+		}
+		
+		file_pos = ofilepos; // adjusted below
+
+	} else if (_capture_start) {
+
+		/* start of capture both occur within the data we are writing,
+		   so do the fade in
+		*/
+
+		_capture_start = false;
+		_capture_end = false;
+		
+		/* move to the correct location place */
+		file_pos = capture_start_frame - timeline_position;
+
+		if (crossfade (data, cnt, 1) != cnt) {
+			return 0;
+		}
+		
+	} else if (_capture_end) {
+
+		/* end of capture both occur within the data we are writing,
+		   so do the fade out
+		*/
+
+		_capture_start = false;
+		_capture_end = false;
+		
+		if (crossfade (data, cnt, 0) != cnt) {
+			return 0;
+		}
+
+	} else {
+
+		/* in the middle of recording */
+
+		if (write_float (data, file_pos, cnt) != cnt) {
+			return 0;
+		}
+	}
+
+	old_file_pos = file_pos;
+	update_length (file_pos, cnt);
+	file_pos += cnt;
+
+	if (_build_peakfiles) {
+		PeakBuildRecord *pbr = 0;
+		
+		if (pending_peak_builds.size()) {
+			pbr = pending_peak_builds.back();
+		}
+		
+		if (pbr && pbr->frame + pbr->cnt == old_file_pos) {
+			
+			/* the last PBR extended to the start of the current write,
+			   so just extend it again.
+			*/
+			
+			pbr->cnt += cnt;
+		} else {
+			pending_peak_builds.push_back (new PeakBuildRecord (old_file_pos, cnt));
+		}
+		
+		_peaks_built = false;
+	}
+
+	if (_build_peakfiles) {
+		queue_for_peaks (shared_from_this ());
+	}
+	
+	return cnt;
+}
+
 int
 SndFileSource::update_header (nframes_t when, struct tm& now, time_t tnow)
 {	
@@ -526,3 +672,221 @@ SndFileSource::natural_position() const
 {
 	return timeline_position;
 }
+
+bool
+SndFileSource::set_destructive (bool yn)
+{
+	if (yn) {
+		_flags = Flag (_flags | Destructive);
+		clear_capture_marks ();
+		timeline_position = header_position_offset;
+	} else {
+		_flags = Flag (_flags & ~Destructive);
+		timeline_position = 0;
+	}
+
+	return true;
+}
+
+void
+SndFileSource::clear_capture_marks ()
+{
+	_capture_start = false;
+	_capture_end = false;
+}	
+
+void
+SndFileSource::mark_capture_start (nframes_t pos)
+{
+	if (destructive()) {
+		if (pos < timeline_position) {
+			_capture_start = false;
+		} else {
+			_capture_start = true;
+			capture_start_frame = pos;
+		}
+	}
+}
+
+void
+SndFileSource::mark_capture_end()
+{
+	if (destructive()) {
+		_capture_end = true;
+	}
+}
+
+nframes_t
+SndFileSource::crossfade (Sample* data, nframes_t cnt, int fade_in)
+{
+	nframes_t xfade = min (xfade_frames, cnt);
+	nframes_t nofade = cnt - xfade;
+	Sample* fade_data = 0;
+	nframes_t fade_position = 0; // in frames
+	ssize_t retval;
+	nframes_t file_cnt;
+
+	if (fade_in) {
+		fade_position = file_pos;
+		fade_data = data;
+	} else {
+		fade_position = file_pos + nofade;
+		fade_data = data + nofade;
+	}
+
+	if (fade_position > _length) {
+		
+		/* read starts beyond end of data, just memset to zero */
+		
+		file_cnt = 0;
+
+	} else if (fade_position + xfade > _length) {
+		
+		/* read ends beyond end of data, read some, memset the rest */
+		
+		file_cnt = _length - fade_position;
+
+	} else {
+		
+		/* read is entirely within data */
+
+		file_cnt = xfade;
+	}
+
+	if (file_cnt) {
+		
+		if ((retval = read_unlocked (xfade_buf, fade_position, file_cnt)) != (ssize_t) file_cnt) {
+			if (retval >= 0 && errno == EAGAIN) {
+				/* XXX - can we really trust that errno is meaningful here?  yes POSIX, i'm talking to you.
+				 * short or no data there */
+				memset (xfade_buf, 0, xfade * sizeof(Sample));
+			} else {
+				error << string_compose(_("SndFileSource: \"%1\" bad read retval: %2 of %5 (%3: %4)"), _path, retval, errno, strerror (errno), xfade) << endmsg;
+				return 0;
+			}
+		}
+	} 
+
+	if (file_cnt != xfade) {
+		nframes_t delta = xfade - file_cnt;
+		memset (xfade_buf+file_cnt, 0, sizeof (Sample) * delta);
+	}
+	
+	if (nofade && !fade_in) {
+		if (write_float (data, file_pos, nofade) != nofade) {
+			error << string_compose(_("SndFileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
+			return 0;
+		}
+	}
+
+	if (xfade == xfade_frames) {
+
+		nframes_t n;
+
+		/* use the standard xfade curve */
+		
+		if (fade_in) {
+
+			/* fade new material in */
+			
+			for (n = 0; n < xfade; ++n) {
+				xfade_buf[n] = (xfade_buf[n] * out_coefficient[n]) + (fade_data[n] * in_coefficient[n]);
+			}
+
+		} else {
+
+
+			/* fade new material out */
+			
+			for (n = 0; n < xfade; ++n) {
+				xfade_buf[n] = (xfade_buf[n] * in_coefficient[n]) + (fade_data[n] * out_coefficient[n]);
+			}
+		}
+
+	} else if (xfade) {
+
+		gain_t in[xfade];
+		gain_t out[xfade];
+
+		/* short xfade, compute custom curve */
+
+		compute_equal_power_fades (xfade, in, out);
+
+		for (nframes_t n = 0; n < xfade; ++n) {
+			xfade_buf[n] = (xfade_buf[n] * out[n]) + (fade_data[n] * in[n]);		
+		}
+	}
+
+	if (xfade) {
+		if (write_float (xfade_buf, fade_position, xfade) != xfade) {
+			error << string_compose(_("SndFileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
+			return 0;
+		}
+	}
+	
+	if (fade_in && nofade) {
+		if (write_float (data + xfade, file_pos + xfade, nofade) != nofade) {
+			error << string_compose(_("SndFileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
+			return 0;
+		}
+	}
+
+	return cnt;
+}
+
+nframes_t
+SndFileSource::last_capture_start_frame () const
+{
+	return capture_start_frame;
+}
+
+void
+SndFileSource::handle_header_position_change ()
+{
+	if (destructive()) {
+		if ( _length != 0 ) {
+			error << string_compose(_("Filesource: start time is already set for existing file (%1): Cannot change start time."), _path ) << endmsg;
+			//in the future, pop up a dialog here that allows user to regenerate file with new start offset
+		} else if (writable()) {
+			timeline_position = header_position_offset;
+			set_header_timeline_position ();  //this will get flushed if/when the file is recorded to
+		}
+	}
+}
+
+void
+SndFileSource::setup_standard_crossfades (nframes_t rate)
+{
+	/* This static method is assumed to have been called by the Session
+	   before any DFS's are created.
+	*/
+
+	xfade_frames = (nframes_t) floor ((Config->get_destructive_xfade_msecs () / 1000.0) * rate);
+
+	cerr << "based on " << Config->get_destructive_xfade_msecs() << " msecs, xfade_frames = " << xfade_frames << endl;
+
+	if (out_coefficient) {
+		delete [] out_coefficient;
+	}
+
+	if (in_coefficient) {
+		delete [] in_coefficient;
+	}
+
+	out_coefficient = new gain_t[xfade_frames];
+	in_coefficient = new gain_t[xfade_frames];
+
+	compute_equal_power_fades (xfade_frames, in_coefficient, out_coefficient);
+}
+
+void
+SndFileSource::set_timeline_position (nframes_t pos)
+{
+	// destructive track timeline postion does not change
+	// except at instantion or when header_position_offset 
+	// (session start) changes
+
+	if (!destructive()) {
+		AudioFileSource::set_timeline_position (pos);
+	} 
+}
diff --git a/libs/ardour/source_factory.cc b/libs/ardour/source_factory.cc
index 7e639590c5..9a3902147b 100644
--- a/libs/ardour/source_factory.cc
+++ b/libs/ardour/source_factory.cc
@@ -55,37 +55,25 @@ SourceFactory::setup_peakfile (boost::shared_ptr<Source> s)
 boost::shared_ptr<Source>
 SourceFactory::create (Session& s, const XMLNode& node)
 {
-	if (node.property (X_("destructive")) != 0) {
-
-		boost::shared_ptr<Source> ret (new DestructiveFileSource (s, node));
+	try {
+		boost::shared_ptr<Source> ret (new CoreAudioSource (s, node));
 		if (setup_peakfile (ret)) {
 			return boost::shared_ptr<Source>();
 		}
 		SourceCreated (ret);
 		return ret;
-		
-	} else {
-		
-		try {
-			boost::shared_ptr<Source> ret (new CoreAudioSource (s, node));
-			if (setup_peakfile (ret)) {
-				return boost::shared_ptr<Source>();
-			}
-			SourceCreated (ret);
-			return ret;
-		} 
-		
-		
-		catch (failed_constructor& err) {
-			boost::shared_ptr<Source> ret (new SndFileSource (s, node));
-			if (setup_peakfile (ret)) {
-				return boost::shared_ptr<Source>();
-			}
-			SourceCreated (ret);
-			return ret;
+	} 
+	
+	
+	catch (failed_constructor& err) {
+		boost::shared_ptr<Source> ret (new SndFileSource (s, node));
+		if (setup_peakfile (ret)) {
+			return boost::shared_ptr<Source>();
 		}
+		SourceCreated (ret);
+		return ret;
 	}
-	
+
 	return boost::shared_ptr<Source>();
 }
 
@@ -94,24 +82,12 @@ SourceFactory::create (Session& s, const XMLNode& node)
 boost::shared_ptr<Source>
 SourceFactory::create (Session& s, const XMLNode& node)
 {
-	if (node.property (X_("destructive")) != 0) {
-		
-		boost::shared_ptr<Source> ret (new DestructiveFileSource (s, node));
-		if (setup_peakfile (ret)) {
-			return boost::shared_ptr<Source>();
-		}
-		SourceCreated (ret);
-		return ret;
-		
-	} else {
-		
-		boost::shared_ptr<Source> ret (new SndFileSource (s, node));
-		if (setup_peakfile (ret)) {
-			return boost::shared_ptr<Source>();
-		}
-		SourceCreated (ret);
-		return ret;
+	boost::shared_ptr<Source> ret (new SndFileSource (s, node));
+	if (setup_peakfile (ret)) {
+		return boost::shared_ptr<Source>();
 	}
+	SourceCreated (ret);
+	return ret;
 }
 
 #endif // HAVE_COREAUDIO
@@ -120,37 +96,42 @@ SourceFactory::create (Session& s, const XMLNode& node)
 boost::shared_ptr<Source>
 SourceFactory::createReadable (Session& s, string idstr, AudioFileSource::Flag flags, bool announce)
 {
-	if (flags & Destructive) {
-		boost::shared_ptr<Source> ret (new DestructiveFileSource (s, idstr, flags));
-		if (setup_peakfile (ret)) {
-			return boost::shared_ptr<Source>();
-		}
-		if (announce) {
-			SourceCreated (ret);
-		}
-		return ret;
-	}
+	if (!(flags & Destructive)) {
 
-	try {
-		boost::shared_ptr<Source> ret (new CoreAudioSource (s, idstr, flags));
-		if (setup_peakfile (ret)) {
-			return boost::shared_ptr<Source>();
+		try {
+			boost::shared_ptr<Source> ret (new CoreAudioSource (s, idstr, flags));
+			if (setup_peakfile (ret)) {
+				return boost::shared_ptr<Source>();
+			}
+			if (announce) {
+				SourceCreated (ret);
+			}
+			return ret;
 		}
-		if (announce) {
-			SourceCreated (ret);
+		
+		catch (failed_constructor& err) {
+			boost::shared_ptr<Source> ret (new SndFileSource (s, idstr, flags));
+			if (setup_peakfile (ret)) {
+				return boost::shared_ptr<Source>();
+			}
+			if (announce) {
+				SourceCreated (ret);
+			}
+			return ret;
 		}
-		return ret;
-	}
 
-	catch (failed_constructor& err) {
-		boost::shared_ptr<Source> ret (new SndFileSource (s, idstr, flags));
-		if (setup_peakfile (ret)) {
-			return boost::shared_ptr<Source>();
-		}
-		if (announce) {
-			SourceCreated (ret);
+	} else {
+
+		catch (failed_constructor& err) {
+			boost::shared_ptr<Source> ret (new SndFileSource (s, idstr, flags));
+			if (setup_peakfile (ret)) {
+				return boost::shared_ptr<Source>();
+			}
+			if (announce) {
+				SourceCreated (ret);
+			}
+			return ret;
 		}
-		return ret;
 	}
 
 	return boost::shared_ptr<Source>();
@@ -178,30 +159,20 @@ SourceFactory::createWritable (Session& s, std::string path, bool destructive, n
 {
 	/* this might throw failed_constructor(), which is OK */
 	
-	if (destructive) {
-		boost::shared_ptr<Source> ret (new DestructiveFileSource (s, path,
-									  Config->get_native_file_data_format(),
-									  Config->get_native_file_header_format(),
-									  rate));
-		if (setup_peakfile (ret)) {
-			return boost::shared_ptr<Source>();
-		}
-		if (announce) {
-			SourceCreated (ret);
-		}
-		return ret;
-		
-	} else {
-		boost::shared_ptr<Source> ret (new SndFileSource (s, path, 
-								  Config->get_native_file_data_format(),
-								  Config->get_native_file_header_format(),
-								  rate));
-		if (setup_peakfile (ret)) {
-			return boost::shared_ptr<Source>();
-		}
-		if (announce) {
-			SourceCreated (ret);
-		}
-		return ret;
+	boost::shared_ptr<Source> ret (new SndFileSource 
+				       (s, path, 
+					Config->get_native_file_data_format(),
+					Config->get_native_file_header_format(),
+					rate,
+					(destructive ? SndFileSource::default_writable_flags : 
+					 AudioFileSource::Flag 
+					 (SndFileSource::default_writable_flags | AudioFileSource::Destructive))));
+
+	if (setup_peakfile (ret)) {
+		return boost::shared_ptr<Source>();
+	}
+	if (announce) {
+		SourceCreated (ret);
 	}
+	return ret;
 }