From 71520c743212de6d4e42fbdfd8bfbd0611600dae Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Wed, 25 Nov 2015 00:55:41 +0100
Subject: Prevent crash at session-close when analysing.

The Analyser only holds a weak-pointer the the Source,
session-destruction frees the actual Source, which is fatal for any
ongoing audio analysis.


This fix simply waits for the current ongoing analysis to complete,
ideally TransientDetector::run, EBUr128Analysis::run, OnsetDetector::run
and AudioAnalyser::analyse could be interrupted.

Alternate option: cancel the Analyser::work thread (and re-create with
the every session).
---
 libs/ardour/analyser.cc       | 10 ++++++++++
 libs/ardour/ardour/analyser.h |  6 ++++--
 libs/ardour/session.cc        |  2 ++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/libs/ardour/analyser.cc b/libs/ardour/analyser.cc
index fa22bd757d..58a8f30245 100644
--- a/libs/ardour/analyser.cc
+++ b/libs/ardour/analyser.cc
@@ -31,6 +31,7 @@ using namespace ARDOUR;
 using namespace PBD;
 
 Analyser* Analyser::the_analyser = 0;
+Glib::Threads::Mutex Analyser::analysis_active_lock;
 Glib::Threads::Mutex Analyser::analysis_queue_lock;
 Glib::Threads::Cond  Analyser::SourcesToAnalyse;
 list<boost::weak_ptr<Source> > Analyser::analysis_queue;
@@ -96,6 +97,7 @@ Analyser::work ()
 		boost::shared_ptr<AudioFileSource> afs = boost::dynamic_pointer_cast<AudioFileSource> (src);
 
 		if (afs && afs->length(afs->timeline_position())) {
+			Glib::Threads::Mutex::Lock lm (analysis_active_lock);
 			analyse_audio_file_source (afs);
 		}
 	}
@@ -119,3 +121,11 @@ Analyser::analyse_audio_file_source (boost::shared_ptr<AudioFileSource> src)
 		return;
 	}
 }
+
+void
+Analyser::flush ()
+{
+	Glib::Threads::Mutex::Lock lq (analysis_queue_lock);
+	Glib::Threads::Mutex::Lock la (analysis_active_lock);
+	analysis_queue.clear();
+}
diff --git a/libs/ardour/ardour/analyser.h b/libs/ardour/ardour/analyser.h
index 8e757ef4e9..fec6bd21e3 100644
--- a/libs/ardour/ardour/analyser.h
+++ b/libs/ardour/ardour/analyser.h
@@ -40,11 +40,13 @@ class LIBARDOUR_API Analyser {
 	static void init ();
 	static void queue_source_for_analysis (boost::shared_ptr<Source>, bool force);
 	static void work ();
+	static void flush ();
 
   private:
 	static Analyser* the_analyser;
-        static Glib::Threads::Mutex analysis_queue_lock;
-        static Glib::Threads::Cond  SourcesToAnalyse;
+	static Glib::Threads::Mutex analysis_active_lock;
+	static Glib::Threads::Mutex analysis_queue_lock;
+	static Glib::Threads::Cond  SourcesToAnalyse;
 	static std::list<boost::weak_ptr<Source> > analysis_queue;
 
 	static void analyse_audio_file_source (boost::shared_ptr<AudioFileSource>);
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index ec8b6e14cc..856e89eced 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -544,6 +544,8 @@ Session::destroy ()
 
 	remove_pending_capture_state ();
 
+	Analyser::flush ();
+
 	_state_of_the_state = StateOfTheState (CannotSave|Deletion);
 
 	/* disconnect from any and all signals that we are connected to */
-- 
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