Mixer: Fix race condition causing invalid read in process thread of Meter_Indicator_Module.

Mixer/JACK_Module.C

@@ -36,6 +36,7 @@ JACK_Module::JACK_Module ( )
         p.hints.type = Port::Hints::INTEGER;
         p.hints.minimum = 0;
         p.hints.maximum = 6;
+        p.hints.ranged = true;
 
         p.connect_to( new float );
         p.control_value_no_callback( 0 );
@@ -48,6 +49,7 @@ JACK_Module::JACK_Module ( )
         p.hints.type = Port::Hints::INTEGER;
         p.hints.minimum = 0;
         p.hints.maximum = 6;
+        p.hints.ranged = true;
 
         p.connect_to( new float );
         p.control_value_no_callback( 0 );
@@ -153,6 +155,8 @@ JACK_Module::initialize ( void )
 void
 JACK_Module::handle_control_changed ( Port *p )
 {
+    THREAD_ASSERT( UI );
+
     if ( 0 == strcmp( p->name(), "Inputs" ) )
     {
         DMESSAGE( "Adjusting number of inputs (JACK outputs)" );
@@ -163,14 +167,20 @@ JACK_Module::handle_control_changed ( Port *p )
     else if ( 0 == strcmp( p->name(), "Outputs" ) )
     {
         DMESSAGE( "Adjusting number of outputs (JACK inputs)" );
-        if ( chain() && chain()->can_configure_outputs( this, p->control_value() ) )
+
+        if ( ! chain() )
+        {
+            configure_outputs( p->control_value() );
+        }
+        else if ( chain()->can_configure_outputs( this, p->control_value() ) )
         {
             configure_outputs( p->control_value() );
             chain()->configure_ports();
         }
         else
-            configure_outputs( p->control_value() );
-
+        {
+            p->connected_port()->control_value( noutputs() );
+        }
     }
 }
 

Mixer/Meter_Indicator_Module.C

@@ -59,7 +59,7 @@ Meter_Indicator_Module::set ( Log_Entry &e )
 {
     Module::set( e );
 
-    int port;
+    int port = -1;
     Module *module = NULL;
 
     for ( int i = 0; i < e.size(); ++i )
@@ -146,7 +146,7 @@ Meter_Indicator_Module::update_cb ( void )
 
         if ( dpm_pack->children() != p->hints.dimensions )
         {
-            engine->lock();
+/*             engine->lock(); */
 
             dpm_pack->clear();
 
@@ -165,7 +165,7 @@ Meter_Indicator_Module::update_cb ( void )
                 dpm->value( -70.0f );
             }
 
-            engine->unlock();
+/*             engine->unlock(); */
         }
         else
         {
@@ -203,6 +203,39 @@ Meter_Indicator_Module::handle ( int m )
 
 
 
+void
+Meter_Indicator_Module::handle_control_changed ( Port *p )
+{
+    THREAD_ASSERT( UI );
+
+    /* The engine is already locked by the UI thread at this point in
+     the call-graph, so we can be sure that process() won't be
+     executed concurrently. */
+    if ( p->connected() )
+    {
+        p = p->connected_port();
+
+        if ( dpm_pack->children() != p->hints.dimensions )
+        {
+            dpm_pack->clear();
+
+            control_value = new float[p->hints.dimensions];
+
+            for ( int i = p->hints.dimensions; i--; )
+            {
+                DPM *dpm = new DPM( x(), y(), w(), h() );
+                dpm->type( FL_VERTICAL );
+                align( (Fl_Align)(FL_ALIGN_CENTER | FL_ALIGN_INSIDE ) );
+
+                dpm_pack->add( dpm );
+
+                control_value[i] = -70.0f;
+                dpm->value( -70.0f );
+            }
+        }
+    }
+}
+
 void
 Meter_Indicator_Module::process ( void )
 {

Mixer/Meter_Indicator_Module.H

@@ -39,6 +39,8 @@ class Meter_Indicator_Module : public Module
 
 public:
 
+    void handle_control_changed ( Port *p );
+
     Meter_Indicator_Module ( bool is_default = false );
     virtual ~Meter_Indicator_Module ( );
 

Mixer/Meter_Module.C

@@ -88,6 +88,8 @@ Meter_Module::update_cb ( void )
 bool
 Meter_Module::configure_inputs ( int n )
 {
+    THREAD_ASSERT( UI );
+
     int tx, ty, tw, th;
     bbox( tx,ty,tw,th );
 
@@ -141,6 +143,9 @@ Meter_Module::configure_inputs ( int n )
     for ( int i = n; i--; )
         control_value[i] = -70.0f;
 
+    if ( control_output[0].connected() )
+        control_output[0].connected_port()->module()->handle_control_changed( control_output[0].connected_port() );
+
     return true;
 }