Internally set LV2_PATH for lilv when needed

source/backend/engine/CarlaEngine.cpp

@@ -430,7 +430,7 @@ bool CarlaEngine::addPlugin(const BinaryType btype, const PluginType ptype, cons
                 uniqueId
             };
 
-            char* const oldVstPath(getenv("VST_PATH"));
+            char* const oldVstPath(std::getenv("VST_PATH"));
             carla_setenv("VST_PATH", file.getParentDirectory().getFullPathName().toRawUTF8());
 
             plugin = CarlaPlugin::newDSSI(init2);

source/backend/plugin/Lv2Plugin.cpp

@@ -4486,6 +4486,12 @@ public:
             return false;
         }
 
+        // ---------------------------------------------------------------
+        // Init LV2 World if needed, sets LV2_PATH for lilv
+
+        Lv2WorldClass& lv2World(Lv2WorldClass::getInstance());
+        lv2World.initIfNeeded(pData->engine->getOptions().pathLV2);
+
         // ---------------------------------------------------------------
         // get plugin from lv2_rdf (lilv)
 

source/utils/CarlaLv2Utils.hpp

@@ -364,13 +364,22 @@ public:
         return lv2World;
     }
 
-    void initIfNeeded()
+    void initIfNeeded(const char* const LV2_PATH)
     {
+        CARLA_SAFE_ASSERT_RETURN(LV2_PATH != nullptr && LV2_PATH[0] != '\0',);
+
         if (! needsInit)
             return;
 
         needsInit = false;
+
+        char* const oldLv2Path(std::getenv("LV2_PATH"));
+        carla_setenv("LV2_PATH", LV2_PATH);
+
         Lilv::World::load_all();
+
+        if (oldLv2Path != nullptr)
+            carla_setenv("LV2_PATH", oldLv2Path);
     }
 
     void load_bundle(const char* const bundle)
@@ -447,15 +456,12 @@ public:
 // Create new RDF object (using lilv)
 
 static inline
-const LV2_RDF_Descriptor* lv2_rdf_new(const LV2_URI uri, const bool doInit)
+const LV2_RDF_Descriptor* lv2_rdf_new(const LV2_URI uri, const bool loadPresets)
 {
     CARLA_SAFE_ASSERT_RETURN(uri != nullptr && uri[0] != '\0', nullptr);
 
     Lv2WorldClass& lv2World(Lv2WorldClass::getInstance());
 
-    if (doInit)
-        lv2World.initIfNeeded();
-
     const LilvPlugin* const cPlugin(lv2World.getPlugin(uri));
 
     if (cPlugin == nullptr)
@@ -1095,7 +1101,7 @@ const LV2_RDF_Descriptor* lv2_rdf_new(const LV2_URI uri, const bool doInit)
     // -------------------------------------------------------------------
     // Set Plugin Presets
 
-    if (doInit)
+    if (loadPresets)
     {
         Lilv::Nodes presetNodes(lilvPlugin.get_related(lv2World.preset_preset));