Continue cleanup and docs

source/backend/CarlaBackend.hpp

@@ -34,7 +34,7 @@ CARLA_BACKEND_START_NAMESPACE
  * @defgroup CarlaBackendAPI Carla Backend API
  *
  * The Carla Backend API.\n
- * This is the base definitions for everything the Carla code.
+ * This is the base definitions for everything in the Carla code.
  *
  * @{
  */
@@ -737,7 +737,7 @@ struct MidiProgramData {
 };
 
 /*!
- * Custom data, saving key:value 'dictionaries'.
+ * Custom data, saving key:value 'dictionaries'.\n
  * \a type is an URI which defines the \a value type.
  *
  * \see CustomDataTypes

source/backend/CarlaEngine.hpp

@@ -757,6 +757,7 @@ public:
      */
     CarlaPlugin* getPluginUnchecked(const unsigned int id) const;
 
+    // FIXME - this one should not be public
     /*!
      * Get a unique plugin name within the engine.\n
      * Returned variable must NOT be free'd.
@@ -769,18 +770,20 @@ public:
     /*!
      * Load \a filename of any type.\n
      * This will try to load a generic file as a plugin,
-     * either by direct handling (GIG, SF2 and SFZ) or by using an internal plugin (like Audio and MIDI)
+     * either by direct handling (GIG, SF2 and SFZ) or by using an internal plugin (like Audio and MIDI).
      */
     bool loadFilename(const char* const filename);
 
     /*!
-     * Load \a filename session.
+     * Load \a filename project file.\n
+     * (project files have *.carxp extension)
      * \note Already loaded plugins are not removed; call removeAllPlugins() first if needed.
      */
     bool loadProject(const char* const filename);
 
     /*!
-     * Save current session to \a filename.
+     * Save current project to \a filename.\n
+     * (project files have *.carxp extension)
      */
     bool saveProject(const char* const filename);
 
@@ -853,6 +856,7 @@ public:
     // -------------------------------------------------------------------
     // Callback
 
+    // FIXME - this one should not be public
     /*!
      * TODO.
      */
@@ -867,17 +871,17 @@ public:
     // Patchbay
 
     /*!
-     * TODO.
+     * Connect patchbay ports \a portA and \a portB.
      */
     virtual bool patchbayConnect(int portA, int portB);
 
     /*!
-     * TODO.
+     * Disconnect patchbay connection \a connectionId.
      */
     virtual bool patchbayDisconnect(int connectionId);
 
     /*!
-     * TODO.
+     * Force the engine to resend all patchbay clients, ports and connections again.
      */
     virtual void patchbayRefresh();
 
@@ -885,17 +889,17 @@ public:
     // Transport
 
     /*!
-     * TODO.
+     * Start playback of the engine transport.
      */
     virtual void transportPlay();
 
     /*!
-     * TODO.
+     * Pause the engine transport.
      */
     virtual void transportPause();
 
     /*!
-     * TODO.
+     * Relocate the engine transport to \a frames.
      */
     virtual void transportRelocate(const uint32_t frame);
 
@@ -907,6 +911,7 @@ public:
      */
     const char* getLastError() const;
 
+    // FIXME - this one should not be public
     /*!
      * Set last error.
      */
@@ -944,6 +949,7 @@ public:
     bool isOscControlRegistered() const;
 #endif
 
+    // FIXME - this one should not be public
     /*!
      * Idle OSC.
      */
@@ -997,6 +1003,11 @@ protected:
      */
     void proccessPendingEvents();
 
+    /*!
+     * TODO.
+     */
+    void setPeaks(const unsigned int pluginId, float const inPeaks[MAX_PEAKS], float const outPeaks[MAX_PEAKS]);
+
 #ifndef BUILD_BRIDGE
     // Rack mode data
     EngineEvent* getRackEventBuffer(const bool isInput);

source/backend/CarlaNative.h

@@ -195,7 +195,7 @@ typedef struct _PluginDescriptor {
     char* (*get_state)(PluginHandle handle);
     void  (*set_state)(PluginHandle handle, const char* data);
 
-    intptr_t (*dispatcher)(PluginHandle handle, int32_t code, int32_t index, intptr_t value, void* ptr);
+    intptr_t (*dispatcher)(PluginHandle handle, int32_t opcode, int32_t index, intptr_t value, void* ptr);
 
 } PluginDescriptor;
 

source/backend/CarlaNative.hpp

@@ -298,6 +298,20 @@ protected:
     }
 
     // -------------------------------------------------------------------
+    // Dispatcher
+
+    virtual intptr_t dispatcher(int32_t opcode, int32_t index, intptr_t value, void* ptr)
+    {
+        return 0;
+
+        // unused
+        (void)opcode;
+        (void)index;
+        (void)value;
+        (void)ptr;
+    }
+
+    // -------------------------------------------------------------------
 
 private:
     const HostDescriptor* const kHost;
@@ -403,6 +417,11 @@ public:
         handlePtr->setState(data);
     }
 
+    static intptr_t _dispatcher(PluginHandle handle, int32_t opcode, int32_t index, intptr_t value, void* ptr)
+    {
+        return handlePtr->dispatcher(opcode, index, value, ptr);
+    }
+
     #undef handlePtr
 
     CARLA_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(PluginDescriptorClass)
@@ -445,6 +464,7 @@ public:
     className::_deactivate,             \
     className::_process,                \
     className::_get_state,              \
-    className::_set_state
+    className::_set_state,              \
+    className::_dispatcher
 
 #endif // __CARLA_NATIVE_HPP__

source/backend/CarlaStandalone.hpp

@@ -308,67 +308,76 @@ CARLA_EXPORT bool carla_is_engine_running();
 CARLA_EXPORT void carla_set_engine_about_to_close();
 
 /*!
- * TODO
+ * Set the engine callback function to \a func.
+ * Use \a ptr to pass a custom pointer to the callback.
  */
 CARLA_EXPORT void carla_set_engine_callback(CarlaCallbackFunc func, void* ptr);
 
 /*!
- * TODO
+ * Set the engine option \a option.\n
+ * With the exception of OPTION_PROCESS_NAME, OPTION_TRANSPORT_MODE and OPTION_PATH_*,
+ * this function should not be called when the engine is running.
  */
 CARLA_EXPORT void carla_set_engine_option(CarlaOptionsType option, int value, const char* valueStr);
 
 /*!
- * TODO
+ * Load \a filename of any type.\n
+ * This will try to load a generic file as a plugin,
+ * either by direct handling (GIG, SF2 and SFZ) or by using an internal plugin (like Audio and MIDI).
+ * \see carla_get_supported_file_types()
  */
 CARLA_EXPORT bool carla_load_filename(const char* filename);
 
 /*!
- * TODO
+ * Load \a filename project file.\n
+ * (project files have *.carxp extension)
+ * \note Already loaded plugins are not removed; call carla_remove_all_plugins() first if needed.
  */
 CARLA_EXPORT bool carla_load_project(const char* filename);
 
 /*!
- * TODO
+ * Save current project to \a filename.\n
+ * (project files have *.carxp extension)
  */
 CARLA_EXPORT bool carla_save_project(const char* filename);
 
 /*!
- * TODO
+ * Connect patchbay ports \a portA and \a portB.
  */
 CARLA_EXPORT bool carla_patchbay_connect(int portA, int portB);
 
 /*!
- * TODO
+ * Disconnect patchbay connection \a connectionId.
  */
 CARLA_EXPORT bool carla_patchbay_disconnect(int connectionId);
 
 /*!
- * TODO
+ * Force the engine to resend all patchbay clients, ports and connections again.
  */
 CARLA_EXPORT void carla_patchbay_refresh();
 
 /*!
- * TODO
+ * Start playback of the engine transport.
  */
 CARLA_EXPORT void carla_transport_play();
 
 /*!
- * TODO
+ * Pause the engine transport.
  */
 CARLA_EXPORT void carla_transport_pause();
 
 /*!
- * TODO
+ * Relocate the engine transport to \a frames.
  */
 CARLA_EXPORT void carla_transport_relocate(uint32_t frames);
 
 /*!
- * TODO
+ * Get the current transport frame.
  */
 CARLA_EXPORT uint32_t carla_get_current_transport_frame();
 
 /*!
- * TODO
+ * Get the engine transport information.
  */
 CARLA_EXPORT const CarlaTransportInfo* carla_get_transport_info();
 
@@ -481,197 +490,208 @@ CARLA_EXPORT const CarlaCustomData* carla_get_custom_data(unsigned int pluginId,
 CARLA_EXPORT const char* carla_get_chunk_data(unsigned int pluginId);
 
 /*!
- * TODO
+ * Get how many parameters a plugin has.
  */
 CARLA_EXPORT uint32_t carla_get_parameter_count(unsigned int pluginId);
 
 /*!
- * TODO
+ * Get how many programs a plugin has.
  */
 CARLA_EXPORT uint32_t carla_get_program_count(unsigned int pluginId);
 
 /*!
- * TODO
+ * Get how many midi programs a plugin has.
  */
 CARLA_EXPORT uint32_t carla_get_midi_program_count(unsigned int pluginId);
 
 /*!
- * TODO
+ * Get how many custom data sets a plugin has.
+ * \see carla_prepare_for_save()
  */
 CARLA_EXPORT uint32_t carla_get_custom_data_count(unsigned int pluginId);
 
 /*!
- * TODO
+ * Get a plugin's custom parameter text display.
+ * \see PARAMETER_USES_CUSTOM_TEXT
  */
 CARLA_EXPORT const char* carla_get_parameter_text(unsigned int pluginId, uint32_t parameterId);
 
 /*!
- * TODO
+ * Get a plugin's program name.
  */
 CARLA_EXPORT const char* carla_get_program_name(unsigned int pluginId, uint32_t programId);
 
 /*!
- * TODO
+ * Get a plugin's midi program name.
  */
 CARLA_EXPORT const char* carla_get_midi_program_name(unsigned int pluginId, uint32_t midiProgramId);
 
 /*!
- * TODO
+ * Get the plugin's real name.\n
+ * This is the name the plugin uses to identify itself; may not be unique.
  */
 CARLA_EXPORT const char* carla_get_real_plugin_name(unsigned int pluginId);
 
 /*!
- * TODO
+ * Get the current plugin's program index.
  */
 CARLA_EXPORT int32_t carla_get_current_program_index(unsigned int pluginId);
 
 /*!
- * TODO
+ * Get the current plugin's midi program index.
  */
 CARLA_EXPORT int32_t carla_get_current_midi_program_index(unsigned int pluginId);
 
 /*!
- * TODO
+ * Get a plugin's default parameter value.
  */
 CARLA_EXPORT float carla_get_default_parameter_value(unsigned int pluginId, uint32_t parameterId);
 
 /*!
- * TODO
+ * Get a plugin's current parameter value.
  */
 CARLA_EXPORT float carla_get_current_parameter_value(unsigned int pluginId, uint32_t parameterId);
 
 /*!
- * TODO
+ * Get a plugin's input peak value.\n
+ * \a portId must only be either 1 or 2
  */
 CARLA_EXPORT float carla_get_input_peak_value(unsigned int pluginId, unsigned short portId);
 
 /*!
- * TODO
+ * Get a plugin's output peak value.\n
+ * \a portId must only be either 1 or 2
  */
 CARLA_EXPORT float carla_get_output_peak_value(unsigned int pluginId, unsigned short portId);
 
 /*!
- * TODO
+ * Enable a plugin's option.
+ * \see PluginOptions
  */
 CARLA_EXPORT void carla_set_option(unsigned int pluginId, unsigned int option, bool yesNo);
 
 /*!
- * TODO
+ * Enable or disable a plugin according to \a onOff.
  */
 CARLA_EXPORT void carla_set_active(unsigned int pluginId, bool onOff);
 
 /*!
- * TODO
+ * Change a plugin's internal drywet value to \a value.
  */
 CARLA_EXPORT void carla_set_drywet(unsigned int pluginId, float value);
 
 /*!
- * TODO
+ * Change a plugin's internal volume value to \a value.
  */
 CARLA_EXPORT void carla_set_volume(unsigned int pluginId, float value);
 
 /*!
- * TODO
+ * Change a plugin's internal balance-left value to \a value.
  */
 CARLA_EXPORT void carla_set_balance_left(unsigned int pluginId, float value);
 
 /*!
- * TODO
+ * Change a plugin's internal balance-right value to \a value.
  */
 CARLA_EXPORT void carla_set_balance_right(unsigned int pluginId, float value);
 
 /*!
- * TODO
+ * Change a plugin's internal panning value to \a value.
  */
 CARLA_EXPORT void carla_set_panning(unsigned int pluginId, float value);
 
 /*!
- * TODO
+ * Change a plugin's internal control channel to \a channel.
  */
 CARLA_EXPORT void carla_set_ctrl_channel(unsigned int pluginId, int8_t channel);
 
 /*!
- * TODO
+ * Set the plugin's parameter \a parameterId to \a value.
  */
 CARLA_EXPORT void carla_set_parameter_value(unsigned int pluginId, uint32_t parameterId, float value);
 
 /*!
- * TODO
+ * Set the plugin's parameter \a parameterId midi channel to \a channel.
  */
 CARLA_EXPORT void carla_set_parameter_midi_channel(unsigned int pluginId, uint32_t parameterId, uint8_t channel);
 
 /*!
- * TODO
+ * Set the plugin's parameter \a parameterId midi cc to \a cc.
  */
 CARLA_EXPORT void carla_set_parameter_midi_cc(unsigned int pluginId, uint32_t parameterId, int16_t cc);
 
 /*!
- * TODO
+ * Change a plugin's program to \a programId.
  */
 CARLA_EXPORT void carla_set_program(unsigned int pluginId, uint32_t programId);
 
 /*!
- * TODO
+ * Change a plugin's midi program to \a midiProgramId.
  */
 CARLA_EXPORT void carla_set_midi_program(unsigned int pluginId, uint32_t midiProgramId);
 
 /*!
- * TODO
+ * Set a plugin's custom data set.
  */
 CARLA_EXPORT void carla_set_custom_data(unsigned int pluginId, const char* type, const char* key, const char* value);
 
 /*!
- * TODO
+ * Set a plugin's chunk data.
  */
 CARLA_EXPORT void carla_set_chunk_data(unsigned int pluginId, const char* chunkData);
 
 /*!
- * TODO
+ * Tell a plugin to prepare for save.\n
+ * This should be called before carla_get_custom_data_count().
  */
 CARLA_EXPORT void carla_prepare_for_save(unsigned int pluginId);
 
 /*!
- * TODO
+ * Send a single note of a plugin.\n
+ * If \a note if 0, note-off is sent; note-on otherwise.
  */
 CARLA_EXPORT void carla_send_midi_note(unsigned int pluginId, uint8_t channel, uint8_t note, uint8_t velocity);
 
 /*!
- * TODO
+ * Tell a plugin to show its own custom UI.
+ * \see PLUGIN_HAS_GUI
  */
 CARLA_EXPORT void carla_show_gui(unsigned int pluginId, bool yesNo);
 
 /*!
- * TODO
+ * Get the current engine buffer size.
  */
 CARLA_EXPORT uint32_t carla_get_buffer_size();
 
 /*!
- * TODO
+ * Get the current engine sample rate.
  */
-CARLA_EXPORT double   carla_get_sample_rate();
+CARLA_EXPORT double carla_get_sample_rate();
 
 /*!
- * TODO
+ * Get the last error.
  */
 CARLA_EXPORT const char* carla_get_last_error();
 
 /*!
- * TODO
+ * Get the current engine OSC URL.
  */
 CARLA_EXPORT const char* carla_get_host_osc_url();
 
 /*!
- * TODO
+ * Send NSM announce message.
  */
 CARLA_EXPORT void carla_nsm_announce(const char* url, int pid);
 
 /*!
- * TODO
+ * Reply to NSM open message.
+ * \see CALLBACK_NSM_OPEN
  */
 CARLA_EXPORT void carla_nsm_reply_open();
 
 /*!
- * TODO
+ * Reply to NSM save message.
+ * \see CALLBACK_NSM_SAVE
  */
 CARLA_EXPORT void carla_nsm_reply_save();
 

source/backend/engine/CarlaEngine.cpp

@@ -882,6 +882,30 @@ void CarlaEngine::removeAllPlugins()
     carla_debug("CarlaEngine::removeAllPlugins() - END");
 }
 
+const char* CarlaEngine::renamePlugin(const unsigned int id, const char* const newName)
+{
+    setLastError("Not implemented yet");
+    return nullptr;
+}
+
+bool CarlaEngine::clonePlugin(const unsigned int id)
+{
+    setLastError("Not implemented yet");
+    return false;
+}
+
+bool CarlaEngine::replacePlugin(const unsigned int id)
+{
+    setLastError("Not implemented yet");
+    return false;
+}
+
+bool CarlaEngine::switchPlugins(const unsigned int idA, const unsigned int idB)
+{
+    setLastError("Not implemented yet");
+    return false;
+}
+
 CarlaPlugin* CarlaEngine::getPlugin(const unsigned int id) const
 {
     carla_debug("CarlaEngine::getPlugin(%i) [count:%i]", id, kData->curPluginCount);
@@ -1148,14 +1172,16 @@ void CarlaEngine::setCallback(const CallbackFunc func, void* const ptr)
 // -----------------------------------------------------------------------
 // Patchbay
 
-void CarlaEngine::patchbayConnect(int, int)
+bool CarlaEngine::patchbayConnect(int, int)
 {
-    // nothing
+    setLastError("Unsupported operation");
+    return false;
 }
 
-void CarlaEngine::patchbayDisconnect(int)
+bool CarlaEngine::patchbayDisconnect(int)
 {
-    // nothing
+    setLastError("Unsupported operation");
+    return false;
 }
 
 void CarlaEngine::patchbayRefresh()

source/backend/engine/CarlaEngineJack.cpp

@@ -744,25 +744,37 @@ public:
     // -------------------------------------------------------------------
     // Patchbay
 
-    void patchbayConnect(int portA, int portB)
+    bool patchbayConnect(int portA, int portB)
     {
         CARLA_ASSERT(fClient != nullptr);
 
         if (fClient == nullptr)
-            return;
+        {
+            setLastError("Invalid JACK client");
+            return false;
+        }
 
         const char* const portNameA = getFullPortName(portA).toUtf8().constData();
         const char* const portNameB = getFullPortName(portB).toUtf8().constData();
 
-        jack_connect(fClient, portNameA, portNameB);
+        if (jack_connect(fClient, portNameA, portNameB) != 0)
+        {
+            setLastError("JACK operation failed");
+            return false;
+        }
+
+        return true;
     }
 
-    void patchbayDisconnect(int connectionId)
+    bool patchbayDisconnect(int connectionId)
     {
         CARLA_ASSERT(fClient != nullptr);
 
         if (fClient == nullptr)
-            return;
+        {
+            setLastError("Invalid JACK client");
+            return false;
+        }
 
         for (int i=0, count=fUsedConnections.count(); i < count; i++)
         {
@@ -771,10 +783,18 @@ public:
                 const char* const portNameA = getFullPortName(fUsedConnections[i].portOut).toUtf8().constData();
                 const char* const portNameB = getFullPortName(fUsedConnections[i].portIn).toUtf8().constData();
 
-                jack_disconnect(fClient, portNameA, portNameB);
-                break;
+                if (jack_disconnect(fClient, portNameA, portNameB) != 0)
+                {
+                    setLastError("JACK operation failed");
+                    return false;
+                }
+
+                return true;
             }
         }
+
+        setLastError("Failed to find the requested connection");
+        return false;
     }
 
     void patchbayRefresh()

source/backend/native/audiofile.c

@@ -666,7 +666,9 @@ static const PluginDescriptor audiofileDesc = {
     .process    = audiofile_process,
 
     .get_state = NULL,
-    .set_state = NULL
+    .set_state = NULL,
+
+    .dispatcher = NULL
 };
 
 // -----------------------------------------------------------------------

source/backend/native/bypass.c

@@ -86,7 +86,9 @@ static const PluginDescriptor bypassDesc = {
     .process    = bypass_process,
 
     .get_state = NULL,
-    .set_state = NULL
+    .set_state = NULL,
+
+    .dispatcher = NULL
 };
 
 // -----------------------------------------------------------------------

source/backend/native/lfo.c

@@ -296,7 +296,9 @@ static const PluginDescriptor lfoDesc = {
     .process    = lfo_process,
 
     .get_state = NULL,
-    .set_state = NULL
+    .set_state = NULL,
+
+    .dispatcher = NULL
 };
 
 // -----------------------------------------------------------------------

source/backend/native/midi-split.c

@@ -122,7 +122,9 @@ static const PluginDescriptor midiSplitDesc = {
     .process    = midiSplit_process,
 
     .get_state = NULL,
-    .set_state = NULL
+    .set_state = NULL,
+
+    .dispatcher = NULL
 };
 
 // -----------------------------------------------------------------------

source/backend/native/midi-through.c

@@ -103,7 +103,9 @@ static const PluginDescriptor midiThroughDesc = {
     .process    = midiThrough_process,
 
     .get_state = NULL,
-    .set_state = NULL
+    .set_state = NULL,
+
+    .dispatcher = NULL
 };
 
 // -----------------------------------------------------------------------

source/backend/native/midi-transpose.c

@@ -185,7 +185,9 @@ static const PluginDescriptor midiTransposeDesc = {
     .process    = midiTranspose_process,
 
     .get_state = NULL,
-    .set_state = NULL
+    .set_state = NULL,
+
+    .dispatcher = NULL
 };
 
 // -----------------------------------------------------------------------

source/backend/native/nekofilter.c

@@ -65,7 +65,9 @@ static const PluginDescriptor nekofilterDesc = {
     .process    = nekofilter_process,
 
     .get_state = NULL,
-    .set_state = NULL
+    .set_state = NULL,
+
+    .dispatcher = NULL
 };
 
 // -----------------------------------------------------------------------

source/backend/standalone/CarlaStandalone.cpp

@@ -37,6 +37,7 @@ using CarlaBackend::CarlaEngine;
 using CarlaBackend::CarlaPlugin;
 using CarlaBackend::CallbackFunc;
 using CarlaBackend::EngineOptions;
+using CarlaBackend::EngineTimeInfo;
 
 // -------------------------------------------------------------------------------------------------------------------
 // Single, standalone engine
@@ -467,7 +468,7 @@ void carla_set_engine_callback(CarlaCallbackFunc func, void* ptr)
         standalone.engine->setCallback(func, ptr);
 }
 
-void carla_set_engine_option(CarlaBackend::OptionsType option, int value, const char* valueStr)
+void carla_set_engine_option(CarlaOptionsType option, int value, const char* valueStr)
 {
     carla_debug("carla_set_engine_option(%s, %i, \"%s\")", CarlaBackend::OptionsType2Str(option), value, valueStr);
 
@@ -707,7 +708,7 @@ uint32_t carla_get_current_transport_frame()
 
     if (standalone.engine != nullptr)
     {
-        const CarlaBackend::EngineTimeInfo& timeInfo(standalone.engine->getTimeInfo());
+        const EngineTimeInfo& timeInfo(standalone.engine->getTimeInfo());
         return timeInfo.frame;
     }
 
@@ -722,7 +723,7 @@ const CarlaTransportInfo* carla_get_transport_info()
 
     if (standalone.engine != nullptr)
     {
-        const CarlaBackend::EngineTimeInfo& timeInfo(standalone.engine->getTimeInfo());
+        const EngineTimeInfo& timeInfo(standalone.engine->getTimeInfo());
 
         info.playing = timeInfo.playing;
         info.frame   = timeInfo.frame;
@@ -757,7 +758,7 @@ const CarlaTransportInfo* carla_get_transport_info()
 
 // -------------------------------------------------------------------------------------------------------------------
 
-bool carla_add_plugin(CarlaBackend::BinaryType btype, CarlaBackend::PluginType ptype, const char* filename, const char* const name, const char* label, const void* extraStuff)
+bool carla_add_plugin(CarlaBinaryType btype, CarlaPluginType ptype, const char* filename, const char* const name, const char* label, const void* extraStuff)
 {
     carla_debug("carla_add_plugin(%s, %s, \"%s\", \"%s\", \"%s\", %p)", CarlaBackend::BinaryType2Str(btype), CarlaBackend::PluginType2Str(ptype), filename, name, label, extraStuff);
     CARLA_ASSERT(standalone.engine != nullptr);
@@ -845,8 +846,11 @@ bool carla_load_plugin_state(unsigned int pluginId, const char* filename)
     carla_debug("carla_load_plugin_state(%i, \"%s\")", pluginId, filename);
     CARLA_ASSERT(standalone.engine != nullptr);
 
-    if (standalone.engine == nullptr)
+    if (standalone.engine == nullptr || ! standalone.engine->isRunning())
+    {
+        standalone.lastError = "Engine is not started";
         return false;
+    }
 
     if (CarlaPlugin* const plugin = standalone.engine->getPlugin(pluginId))
         return plugin->loadStateFromFile(filename);
@@ -861,7 +865,10 @@ bool carla_save_plugin_state(unsigned int pluginId, const char* filename)
     CARLA_ASSERT(standalone.engine != nullptr);
 
     if (standalone.engine == nullptr)
+    {
+        standalone.lastError = "Engine is not started";
         return false;
+    }
 
     if (CarlaPlugin* const plugin = standalone.engine->getPlugin(pluginId))
         return plugin->saveStateToFile(filename);
@@ -1372,7 +1379,6 @@ const char* carla_get_program_name(unsigned int pluginId, uint32_t programId)
         if (programId < plugin->programCount())
         {
             plugin->getProgramName(programId, programName);
-
             return programName;
         }
 
@@ -1400,7 +1406,6 @@ const char* carla_get_midi_program_name(unsigned int pluginId, uint32_t midiProg
         if (midiProgramId < plugin->midiProgramCount())
         {
             plugin->getMidiProgramName(midiProgramId, midiProgramName);
-
             return midiProgramName;
         }
 
@@ -1426,7 +1431,6 @@ const char* carla_get_real_plugin_name(unsigned int pluginId)
     if (CarlaPlugin* const plugin = standalone.engine->getPlugin(pluginId))
     {
         plugin->getRealName(realPluginName);
-
         return realPluginName;
     }
 
@@ -1520,17 +1524,7 @@ float carla_get_input_peak_value(unsigned int pluginId, unsigned short portId)
     if (standalone.engine == nullptr)
         return 0.0f;
 
-    if (pluginId >= standalone.engine->currentPluginCount())
-    {
-        carla_stderr2("carla_get_input_peak_value(%i, %i) - invalid plugin value", pluginId, portId);
-        return 0.0f;
-    }
-
-    if (portId == 1 || portId == 2)
-       return standalone.engine->getInputPeak(pluginId, portId);
-
-    carla_stderr2("carla_get_input_peak_value(%i, %i) - invalid port value", pluginId, portId);
-    return 0.0f;
+    return standalone.engine->getInputPeak(pluginId, portId);
 }
 
 float carla_get_output_peak_value(unsigned int pluginId, unsigned short portId)
@@ -1541,17 +1535,7 @@ float carla_get_output_peak_value(unsigned int pluginId, unsigned short portId)
     if (standalone.engine == nullptr)
         return 0.0f;
 
-    if (pluginId >= standalone.engine->currentPluginCount())
-    {
-        carla_stderr2("carla_get_input_peak_value(%i, %i) - invalid plugin value", pluginId, portId);
-        return 0.0f;
-    }
-
-    if (portId == 1 || portId == 2)
-       return standalone.engine->getOutputPeak(pluginId, portId);
-
-    carla_stderr2("carla_get_output_peak_value(%i, %i) - invalid port value", pluginId, portId);
-    return 0.0f;
+    return standalone.engine->getOutputPeak(pluginId, portId);
 }
 
 // -------------------------------------------------------------------------------------------------------------------
@@ -1748,6 +1732,8 @@ void carla_set_parameter_midi_cc(unsigned int pluginId, uint32_t parameterId, in
     carla_stderr2("carla_set_parameter_midi_cc(%i, %i, %i) - could not find plugin", pluginId, parameterId, cc);
 }
 
+// -------------------------------------------------------------------------------------------------------------------
+
 void carla_set_program(unsigned int pluginId, uint32_t programId)
 {
     carla_debug("carla_set_program(%i, %i)", pluginId, programId);
@@ -1910,7 +1896,10 @@ const char* carla_get_host_osc_url()
     CARLA_ASSERT(standalone.engine != nullptr);
 
     if (standalone.engine == nullptr)
+    {
+        standalone.lastError = "Engine is not started";
         return nullptr;
+    }
 
     return standalone.engine->getOscServerPathTCP();
 }