Carla: Fix jack latency code

I still don't understand how all of this is supposed to work...

c++/carla-backend/carla_engine.cpp

@@ -810,7 +810,8 @@ CarlaEngineClient::CarlaEngineClient(const CarlaEngineClientNativeHandle& handle
     qDebug("CarlaEngineClient::CarlaEngineClient()");
     CARLA_ASSERT(handle.type != CarlaEngineTypeNull);
 
-    m_active = false;
+    m_active  = false;
+    m_latency = 0;
 }
 
 CarlaEngineClient::~CarlaEngineClient()
@@ -895,8 +896,15 @@ bool CarlaEngineClient::isOk() const
     return true;
 }
 
-void CarlaEngineClient::recomputeLatencies()
+uint32_t CarlaEngineClient::getLatency() const
+{
+    return m_latency;
+}
+
+void CarlaEngineClient::setLatency(const uint32_t samples)
 {
+    m_latency = samples;
+
 #ifndef BUILD_BRIDGE
     if (carlaOptions.processMode != PROCESS_MODE_CONTINUOUS_RACK)
 #endif
@@ -986,23 +994,12 @@ CarlaEngineAudioPort::CarlaEngineAudioPort(const CarlaEnginePortNativeHandle& ha
     : CarlaEngineBasePort(handle, isInput)
 {
     qDebug("CarlaEngineAudioPort::CarlaEngineAudioPort(%s)", bool2str(isInput));
-    latency = 0;
 }
 
 void CarlaEngineAudioPort::initBuffer(CarlaEngine* const /*engine*/)
 {
 }
 
-uint32_t CarlaEngineAudioPort::getLatency() const
-{
-    return latency;
-}
-
-void CarlaEngineAudioPort::setLatency(const uint32_t samples)
-{
-    latency = samples;
-}
-
 #ifdef CARLA_ENGINE_JACK
 float* CarlaEngineAudioPort::getJackAudioBuffer(uint32_t nframes)
 {

c++/carla-backend/carla_engine.h

@@ -426,12 +426,14 @@ public:
     bool isActive() const;
     bool isOk() const;
 
-    void recomputeLatencies();
+    uint32_t getLatency() const;
+    void setLatency(const uint32_t samples);
 
     const CarlaEngineBasePort* addPort(const CarlaEnginePortType portType, const char* const name, const bool isInput);
 
 private:
     bool m_active;
+    uint32_t m_latency;
     const CarlaEngineClientNativeHandle handle;
 };
 
@@ -465,15 +467,9 @@ public:
 
     void initBuffer(CarlaEngine* const engine);
 
-    uint32_t getLatency() const;
-    void setLatency(const uint32_t samples);
-
 #ifdef CARLA_ENGINE_JACK
     float* getJackAudioBuffer(uint32_t nframes);
 #endif
-
-private:
-    uint32_t latency;
 };
 
 // control

c++/carla-backend/carla_engine_jack.cpp

@@ -475,7 +475,7 @@ protected:
 #endif
     }
 
-    void handleLatencyCallback()
+    void handleLatencyCallback(jack_latency_callback_mode_t mode)
     {
 #ifndef BUILD_BRIDGE
         if (carlaOptions.processMode != PROCESS_MODE_SINGLE_CLIENT)
@@ -485,7 +485,9 @@ protected:
         for (unsigned short i=0, max=maxPluginNumber(); i < max; i++)
         {
             CarlaPlugin* const plugin = getPluginUnchecked(i);
-            latencyPlugin(plugin);
+
+            if (plugin && plugin->enabled())
+                latencyPlugin(plugin, mode);
         }
     }
 
@@ -494,7 +496,9 @@ protected:
         for (unsigned short i=0, max=maxPluginNumber(); i < max; i++)
         {
             CarlaPlugin* const plugin = getPluginUnchecked(i);
-            plugin->x_client = nullptr;
+
+            if (plugin)
+                plugin->x_client = nullptr;
         }
 
         client = nullptr;
@@ -569,20 +573,41 @@ private:
             zeroF(p->aOut.ports[i]->getJackAudioBuffer(nframes), nframes);
     }
 
-    static void latencyPlugin(CarlaPlugin* const p)
+    static void latencyPlugin(CarlaPlugin* const p, jack_latency_callback_mode_t mode)
     {
-        for (uint32_t i=0; i < p->aIn.count; i++)
-        {
-            const CarlaEngineAudioPort* const port = p->aIn.ports[i];
-            jack_port_t* const jackPort = port->getHandle().jackPort;
-            jack_latency_range_t range;
-
-            jackbridge_port_get_latency_range(jackPort, JackPlaybackLatency, &range);
+        jack_latency_range_t range;
+        uint32_t pluginLatency = p->x_client->getLatency();
 
-            range.min += port->getLatency();
-            range.max += port->getLatency();
+        if (pluginLatency == 0)
+            return;
 
-            jackbridge_port_set_latency_range(jackPort, JackPlaybackLatency, &range);
+        if (mode == JackCaptureLatency)
+        {
+            for (uint32_t i=0; i < p->aIn.count; i++)
+            {
+                uint aOutI = (i >= p->aOut.count) ? p->aOut.count : i;
+                jack_port_t* const portIn  = p->aIn.ports[i]->getHandle().jackPort;
+                jack_port_t* const portOut = p->aOut.ports[aOutI]->getHandle().jackPort;
+
+                jackbridge_port_get_latency_range(portIn, mode, &range);
+                range.min += pluginLatency;
+                range.max += pluginLatency;
+                jackbridge_port_set_latency_range(portOut, mode, &range);
+            }
+        }
+        else
+        {
+            for (uint32_t i=0; i < p->aOut.count; i++)
+            {
+                uint aInI = (i >= p->aIn.count) ? p->aIn.count : i;
+                jack_port_t* const portIn  = p->aIn.ports[aInI]->getHandle().jackPort;
+                jack_port_t* const portOut = p->aOut.ports[i]->getHandle().jackPort;
+
+                jackbridge_port_get_latency_range(portOut, mode, &range);
+                range.min += pluginLatency;
+                range.max += pluginLatency;
+                jackbridge_port_set_latency_range(portIn, mode, &range);
+            }
         }
     }
 
@@ -637,22 +662,16 @@ private:
 
     static void carla_jack_latency_callback(jack_latency_callback_mode_t mode, void* arg)
     {
-        if (mode != JackPlaybackLatency)
-            return;
-
         CarlaEngineJack* const _this_ = (CarlaEngineJack*)arg;
-        _this_->handleLatencyCallback();
+        _this_->handleLatencyCallback(mode);
     }
 
     static void carla_jack_latency_callback_plugin(jack_latency_callback_mode_t mode, void* arg)
     {
-        if (mode != JackPlaybackLatency)
-            return;
-
         CarlaPlugin* const plugin = (CarlaPlugin*)arg;
 
         if (plugin && plugin->enabled())
-            latencyPlugin(plugin);
+            latencyPlugin(plugin, mode);
     }
 
     static void carla_jack_shutdown_callback(void* arg)

c++/carla-backend/dssi.cpp

@@ -697,6 +697,7 @@ public:
             m_hints |= PLUGIN_CAN_FORCE_STEREO;
 
         // check latency
+        if (m_hints & PLUGIN_CAN_DRYWET)
         {
             bool hasLatency = false;
             m_latency = 0;
@@ -739,10 +740,7 @@ public:
 
             if (hasLatency)
             {
-                for (uint32_t i=0; i < aIn.count; i++)
-                    aIn.ports[i]->setLatency(m_latency);
-
-                x_client->recomputeLatencies();
+                x_client->setLatency(m_latency);
                 recreateLatencyBuffers();
             }
         }

c++/carla-backend/ladspa.cpp

@@ -666,6 +666,7 @@ public:
             m_hints |= PLUGIN_CAN_FORCE_STEREO;
 
         // check latency
+        if (m_hints & PLUGIN_CAN_DRYWET)
         {
             bool hasLatency = false;
             m_latency = 0;
@@ -708,10 +709,7 @@ public:
 
             if (hasLatency)
             {
-                for (uint32_t i=0; i < aIn.count; i++)
-                    aIn.ports[i]->setLatency(m_latency);
-
-                x_client->recomputeLatencies();
+                x_client->setLatency(m_latency);
                 recreateLatencyBuffers();
             }
         }

c++/carla-backend/lv2.cpp

@@ -1777,6 +1777,7 @@ public:
         }
 
         // check latency
+        if (m_hints & PLUGIN_CAN_DRYWET)
         {
             bool hasLatency = false;
             m_latency = 0;
@@ -1810,10 +1811,7 @@ public:
 
             if (hasLatency)
             {
-                for (uint32_t i=0; i < aIn.count; i++)
-                    aIn.ports[i]->setLatency(m_latency);
-
-                x_client->recomputeLatencies();
+                x_client->setLatency(m_latency);
                 recreateLatencyBuffers();
             }
         }

c++/carla-backend/vst.cpp

@@ -730,6 +730,7 @@ public:
             m_hints |= PLUGIN_CAN_FORCE_STEREO;
 
         // check latency
+        if (m_hints & PLUGIN_CAN_DRYWET)
         {
 #ifdef VESTIGE_HEADER
             char* const empty3Ptr = &effect->empty3[0];
@@ -739,10 +740,7 @@ public:
             m_latency = effect->initialDelay;
 #endif
 
-            for (uint32_t i=0; i < aIn.count; i++)
-                aIn.ports[i]->setLatency(m_latency);
-
-            x_client->recomputeLatencies();
+            x_client->setLatency(m_latency);
             recreateLatencyBuffers();
         }