Replace control list locks with RWLocks4.0-rc4

towards fixing #6238 and #6096.


GUI thread:
#2  Glib::Threads::Mutex::Lock::Lock
#3  Evoral::ControlList::eval 
#4  Evoral::Control::get_double 
#5  ARDOUR::AutomationControl::get_value
#6  ProcessorEntry::Control::control_changed
..
#15 PBD::Timer::timeout_handler


at the same time: Audio Thread (try-lock, fails)

#0  Evoral::Curve::rt_safe_get_vector
#1  ARDOUR::Amp::setup_gain_automation
#2  ARDOUR::Route::process_output_buffers

Due to the failed try-lock.. AMP::_apply_gain_automation
is false. and Amp::run() uses a different gain factor.
-> click.

1 files changed, 6 insertions, 6 deletions

diff --git a/libs/evoral/evoral/ControlList.hpp b/libs/evoral/evoral/ControlList.hpp
index 6353813097..7a828264bd 100644
--- a/libs/evoral/evoral/ControlList.hpp
+++ b/libs/evoral/evoral/ControlList.hpp
@@ -109,7 +109,7 @@ public:
 
 	EventList::size_type size() const { return _events.size(); }
         double length() const { 		
-		Glib::Threads::Mutex::Lock lm (_lock);
+		Glib::Threads::RWLock::ReaderLock lm (_lock);
 		return _events.empty() ? 0.0 : _events.back()->when;
 	}
 	bool empty() const { return _events.empty(); }
@@ -184,18 +184,18 @@ public:
 	std::pair<ControlList::iterator,ControlList::iterator> control_points_adjacent (double when);
 
 	template<class T> void apply_to_points (T& obj, void (T::*method)(const ControlList&)) {
-		Glib::Threads::Mutex::Lock lm (_lock);
+		Glib::Threads::RWLock::WriterLock lm (_lock);
 		(obj.*method)(*this);
 	}
 
 	double eval (double where) {
-		Glib::Threads::Mutex::Lock lm (_lock);
+		Glib::Threads::RWLock::ReaderLock lm (_lock);
 		return unlocked_eval (where);
 	}
 
 	double rt_safe_eval (double where, bool& ok) {
 
-		Glib::Threads::Mutex::Lock lm (_lock, Glib::Threads::TRY_LOCK);
+		Glib::Threads::RWLock::ReaderLock lm (_lock, Glib::Threads::TRY_LOCK);
 
 		if ((ok = lm.locked())) {
 			return unlocked_eval (where);
@@ -226,7 +226,7 @@ public:
 	double default_value() const { return _default_value; }
 
 	// FIXME: const violations for Curve
-	Glib::Threads::Mutex& lock()         const { return _lock; }
+	Glib::Threads::RWLock& lock()       const { return _lock; }
 	LookupCache& lookup_cache() const { return _lookup_cache; }
 	SearchCache& search_cache() const { return _search_cache; }
 
@@ -297,7 +297,7 @@ protected:
 	mutable LookupCache   _lookup_cache;
 	mutable SearchCache   _search_cache;
 
-	mutable Glib::Threads::Mutex _lock;
+	mutable Glib::Threads::RWLock _lock;
 
 	Parameter             _parameter;
 	ParameterDescriptor   _desc;