Plugin instances managed without naked new and delete

src/PluginManager.cpp

@@ -1053,13 +1053,17 @@ PluginDescriptor::PluginDescriptor()
 }
 
 PluginDescriptor::~PluginDescriptor()
+{
+   DeleteInstance();
+}
+
+void PluginDescriptor::DeleteInstance()
 {
    if (mInstance)
    {
       ModuleManager::Get().DeleteInstance(GetProviderID(), mInstance);
+      mInstance = nullptr;
    }
-
-   return;
 }
 
 bool PluginDescriptor::IsInstantiated() const
@@ -1086,6 +1090,12 @@ IdentInterface *PluginDescriptor::GetInstance()
 
 void PluginDescriptor::SetInstance(IdentInterface *instance)
 {
+   if (mInstance && mInstance != instance)
+   {
+      // Be sure not to leak resources!!
+      DeleteInstance();
+   }
+
    mInstance = instance;
 
    return;

src/PluginManager.h

@@ -117,8 +117,13 @@ public:
 
 private:
 
+   void DeleteInstance();
+
    // Common
 
+   // Among other purposes, PluginDescriptor acts as the resouce handle,
+   // or smart pointer, to a resource created in a plugin library, and is responsible
+   // for a cleanup of this pointer.
    IdentInterface *mInstance;
 
    PluginType mPluginType;

src/effects/LoadEffects.cpp

@@ -327,16 +327,17 @@ bool BuiltinEffectsModule::IsPluginValid(const wxString & path)
 
 IdentInterface *BuiltinEffectsModule::CreateInstance(const wxString & path)
 {
+   // Acquires a resource for the application.
+   // Safety of this depends on complementary calls to DeleteInstance on the module manager side.
    return Instantiate(path);
 }
 
 void BuiltinEffectsModule::DeleteInstance(IdentInterface *instance)
 {
-   Effect *effect = dynamic_cast<Effect *>(instance);
-   if (effect)
-   {
-      delete effect;
-   }
+   // Releases the resource.
+   std::unique_ptr < Effect > {
+      dynamic_cast<Effect *>(instance)
+   };
 }
 
 // ============================================================================

src/effects/VST/VSTEffect.cpp

@@ -623,17 +623,17 @@ bool VSTEffectsModule::IsPluginValid(const wxString & path)
 
 IdentInterface *VSTEffectsModule::CreateInstance(const wxString & path)
 {
+   // Acquires a resource for the application.
    // For us, the ID is simply the path to the effect
-   return new VSTEffect(path);
+   // Safety of this depends on complementary calls to DeleteInstance on the module manager side.
+   return safenew VSTEffect(path);
 }
 
 void VSTEffectsModule::DeleteInstance(IdentInterface *instance)
 {
-   VSTEffect *effect = dynamic_cast<VSTEffect *>(instance);
-   if (effect)
-   {
-      delete effect;
-   }
+   std::unique_ptr < VSTEffect > {
+      dynamic_cast<VSTEffect *>(instance)
+   };
 }
 
 // ============================================================================

src/effects/audiounits/AudioUnitEffect.cpp

@@ -176,6 +176,7 @@ bool AudioUnitEffectsModule::IsPluginValid(const wxString & path)
 
 IdentInterface *AudioUnitEffectsModule::CreateInstance(const wxString & path)
 {
+   // Acquires a resource for the application.
    wxString name;
    AudioComponent component = FindAudioUnit(path, name);
    if (component == NULL)
@@ -183,16 +184,15 @@ IdentInterface *AudioUnitEffectsModule::CreateInstance(const wxString & path)
       return NULL;
    }
 
-   return new AudioUnitEffect(path, name, component);
+   // Safety of this depends on complementary calls to DeleteInstance on the module manager side.
+   return safenew AudioUnitEffect(path, name, component);
 }
 
 void AudioUnitEffectsModule::DeleteInstance(IdentInterface *instance)
 {
-   AudioUnitEffect *effect = dynamic_cast<AudioUnitEffect *>(instance);
-   if (effect)
-   {
-      delete effect;
-   }
+   std::unique_ptr < AudioUnitEffect > {
+      dynamic_cast<AudioUnitEffect *>(instance)
+   };
 }
 
 // ============================================================================

src/effects/ladspa/LadspaEffect.cpp

@@ -261,6 +261,7 @@ bool LadspaEffectsModule::IsPluginValid(const wxString & path)
 
 IdentInterface *LadspaEffectsModule::CreateInstance(const wxString & path)
 {
+   // Acquires a resource for the application.
    // For us, the path is two words.
    // 1)  The library's path
    // 2)  The LADSPA descriptor index
@@ -268,16 +269,15 @@ IdentInterface *LadspaEffectsModule::CreateInstance(const wxString & path)
    wxString realPath = path.BeforeFirst(wxT(';'));
    path.AfterFirst(wxT(';')).ToLong(&index);
 
-   return new LadspaEffect(realPath, (int) index);
+   // Safety of this depends on complementary calls to DeleteInstance on the module manager side.
+   return safenew LadspaEffect(realPath, (int)index);
 }
 
 void LadspaEffectsModule::DeleteInstance(IdentInterface *instance)
 {
-   LadspaEffect *effect = dynamic_cast<LadspaEffect *>(instance);
-   if (effect)
-   {
-      delete effect;
-   }
+   std::unique_ptr < LadspaEffect > {
+      dynamic_cast<LadspaEffect *>(instance)
+   };
 }
 
 wxArrayString LadspaEffectsModule::GetSearchPaths()

src/effects/lv2/LoadLV2.cpp

@@ -266,22 +266,22 @@ bool LV2EffectsModule::IsPluginValid(const wxString & path)
 
 IdentInterface *LV2EffectsModule::CreateInstance(const wxString & path)
 {
+   // Acquires a resource for the application.
    const LilvPlugin *plug = GetPlugin(path);
    if (!plug)
    {
       return NULL;
    }
 
-   return new LV2Effect(plug);
+   // Safety of this depends on complementary calls to DeleteInstance on the module manager side.
+   return safenew LV2Effect(plug);
 }
 
 void LV2EffectsModule::DeleteInstance(IdentInterface *instance)
 {
-   LV2Effect *effect = dynamic_cast<LV2Effect *>(instance);
-   if (effect)
-   {
-      delete effect;
-   }
+   std::unique_ptr < LV2Effect > {
+      dynamic_cast<LV2Effect *>(instance)
+   };
 }
 
 // ============================================================================

src/effects/nyquist/LoadNyquist.cpp

@@ -226,24 +226,22 @@ bool NyquistEffectsModule::IsPluginValid(const wxString & path)
 
 IdentInterface *NyquistEffectsModule::CreateInstance(const wxString & path)
 {
-   NyquistEffect *effect = new NyquistEffect(path);
+   // Acquires a resource for the application.
+   auto effect = std::make_unique<NyquistEffect>(path);
    if (effect->IsOk())
    {
-      return effect;
+      // Safety of this depends on complementary calls to DeleteInstance on the module manager side.
+      return effect.release();
    }
 
-   delete effect;
-
    return NULL;
 }
 
 void NyquistEffectsModule::DeleteInstance(IdentInterface *instance)
 {
-   NyquistEffect *effect = dynamic_cast<NyquistEffect *>(instance);
-   if (effect)
-   {
-      delete effect;
-   }
+   std::unique_ptr < NyquistEffect > {
+      dynamic_cast<NyquistEffect *>(instance)
+   };
 }
 
 // ============================================================================

src/effects/vamp/LoadVamp.cpp

@@ -234,13 +234,15 @@ bool VampEffectsModule::IsPluginValid(const wxString & path)
 
 IdentInterface *VampEffectsModule::CreateInstance(const wxString & path)
 {
+   // Acquires a resource for the application.
    int output;
    bool hasParameters;
 
    Plugin *vp = FindPlugin(path, output, hasParameters);
    if (vp)
    {
-      return new VampEffect(vp, path, output, hasParameters);
+      // Safety of this depends on complementary calls to DeleteInstance on the module manager side.
+      return safenew VampEffect(vp, path, output, hasParameters);
    }
 
    return NULL;
@@ -248,11 +250,9 @@ IdentInterface *VampEffectsModule::CreateInstance(const wxString & path)
 
 void VampEffectsModule::DeleteInstance(IdentInterface *instance)
 {
-   VampEffect *effect = dynamic_cast<VampEffect *>(instance);
-   if (effect)
-   {
-      delete effect;
-   }
+   std::unique_ptr < VampEffect > {
+      dynamic_cast<VampEffect *>(instance)
+   };
 }
 
 // VampEffectsModule implementation