From 357e2f802071c2383cc407edc359352d2ccc0f9b Mon Sep 17 00:00:00 2001
From: hotwatermorning <hotwatermorning@gmail.com>
Date: Sun, 25 Aug 2019 18:07:32 +0900
Subject: [PATCH] [plugin/vst3] Use Vst3PluginDestructionListener instead of
 on_destruction function object.

---
 src/plugin/vst3/Vst3Plugin.cpp        | 20 +++++++++++++-------
 src/plugin/vst3/Vst3Plugin.hpp        | 22 ++++++++++++++++++----
 src/plugin/vst3/Vst3PluginFactory.cpp | 21 +++++++++++----------
 3 files changed, 42 insertions(+), 21 deletions(-)

diff --git a/src/plugin/vst3/Vst3Plugin.cpp b/src/plugin/vst3/Vst3Plugin.cpp
index c99118e..78637cd 100644
--- a/src/plugin/vst3/Vst3Plugin.cpp
+++ b/src/plugin/vst3/Vst3Plugin.cpp
@@ -10,22 +10,24 @@ NS_HWM_BEGIN
 using namespace Steinberg;
 
 Vst3Plugin::Vst3Plugin(std::unique_ptr<Impl> pimpl,
-                       std::unique_ptr<HostContext> host_context,
-                       std::function<void(Vst3Plugin const *p)> on_destruction)
+                       std::unique_ptr<HostContext> host_context)
 :   pimpl_(std::move(pimpl))
 ,   host_context_(std::move(host_context))
 {
     host_context_->SetVst3Plugin(this);
-    on_destruction_ = on_destruction;
 }
 
 Vst3Plugin::~Vst3Plugin()
 {
+    vpdls_.Invoke([this](auto *li) {
+        li->OnBeforeDestruction(this);
+    });
+    
     assert(IsEditorOpened() == false);
     
     pimpl_.reset();
+
     host_context_.reset();
-    on_destruction_(this);
 }
 
 FactoryInfo const & Vst3Plugin::GetFactoryInfo() const
@@ -296,12 +298,11 @@ void Vst3Plugin::LoadData(DumpData const &dump)
 std::unique_ptr<Vst3Plugin>
     CreatePlugin(IPluginFactory *factory,
                  FactoryInfo const &factory_info,
-                 ClassInfo const &class_info,
-                 std::function<void(Vst3Plugin const *p)> on_destruction)
+                 ClassInfo const &class_info)
 {
     auto host_context = std::make_unique<Vst3Plugin::HostContext>(kAppName);
     auto impl = std::make_unique<Vst3Plugin::Impl>(factory, factory_info, class_info, host_context->unknownCast());
-    auto plugin = std::make_unique<Vst3Plugin>(std::move(impl), std::move(host_context), on_destruction);
+    auto plugin = std::make_unique<Vst3Plugin>(std::move(impl), std::move(host_context));
     
     return plugin;
 }
@@ -311,4 +312,9 @@ Vst3Plugin::Vst3PluginListenerService & Vst3Plugin::GetVst3PluginListenerService
     return host_context_->vpls_;
 }
 
+Vst3Plugin::Vst3PluginDestructionListenerService & Vst3Plugin::GetVst3PluginDestructionListenerService()
+{
+    return vpdls_;
+}
+
 NS_HWM_END
diff --git a/src/plugin/vst3/Vst3Plugin.hpp b/src/plugin/vst3/Vst3Plugin.hpp
index d2ecca1..5c3e746 100644
--- a/src/plugin/vst3/Vst3Plugin.hpp
+++ b/src/plugin/vst3/Vst3Plugin.hpp
@@ -64,7 +64,19 @@ struct Vst3PluginListener
     {}
     
     virtual void OnNotifyUnitByBusChange(Vst3Plugin *plugin)
-    {}    
+    {}
+};
+
+struct Vst3PluginDestructionListener
+:   IListenerBase
+{
+protected:
+    Vst3PluginDestructionListener()
+    {}
+    
+public:
+    virtual void OnBeforeDestruction(Vst3Plugin *plugin)
+    {}
 };
 
 //! VST3のプラグインを表すクラス
@@ -177,8 +189,7 @@ class Vst3Plugin
 
 public:
 	Vst3Plugin(std::unique_ptr<Impl> pimpl,
-               std::unique_ptr<HostContext> host_context,
-               std::function<void(Vst3Plugin const *p)> on_destruction);
+               std::unique_ptr<HostContext> host_context);
     
 	virtual ~Vst3Plugin();
     
@@ -278,10 +289,13 @@ class Vst3Plugin
     using Vst3PluginListenerService = IListenerService<Vst3PluginListener>;
     Vst3PluginListenerService & GetVst3PluginListenerService();
     
+    using Vst3PluginDestructionListenerService = IListenerService<Vst3PluginDestructionListener>;
+    Vst3PluginDestructionListenerService & GetVst3PluginDestructionListenerService();
+    
 private:
 	std::unique_ptr<Impl> pimpl_;
     std::unique_ptr<HostContext> host_context_;
-    std::function<void(Vst3Plugin const *p)> on_destruction_;
+    ListenerService<Vst3PluginDestructionListener> vpdls_;
 };
 
 NS_HWM_END
diff --git a/src/plugin/vst3/Vst3PluginFactory.cpp b/src/plugin/vst3/Vst3PluginFactory.cpp
index 2418be8..8f451ab 100644
--- a/src/plugin/vst3/Vst3PluginFactory.cpp
+++ b/src/plugin/vst3/Vst3PluginFactory.cpp
@@ -21,8 +21,7 @@ extern
 std::unique_ptr<Vst3Plugin>
     CreatePlugin(IPluginFactory *factory,
                  FactoryInfo const &factory_info,
-                 ClassInfo const &info,
-                 std::function<void(Vst3Plugin const *p)> on_destruction
+                 ClassInfo const &info
                  );
 
 FactoryInfo::FactoryInfo(PFactoryInfo const &info)
@@ -137,6 +136,7 @@ bool ClassInfo::is_instrument() const
 }
 
 class Vst3PluginFactory::Impl
+:   public Vst3PluginDestructionListener
 {
 public:
     Impl(String module_path);
@@ -155,14 +155,16 @@ class Vst3PluginFactory::Impl
         return factory_.get();
     }
     
-    void OnVst3PluginIsCreated(Vst3Plugin const *p) {
-        loaded_plugins_.push_back(p);
+    void OnAfterConstruction(Vst3Plugin *plugin) {
+        loaded_plugins_.push_back(plugin);
+        plugin->GetVst3PluginDestructionListenerService().AddListener(this);
     }
-        
-    void OnVst3PluginIsDestructed(Vst3Plugin const *p) {
-        auto found = std::find(loaded_plugins_.begin(), loaded_plugins_.end(), p);
+    
+    void OnBeforeDestruction(Vst3Plugin *plugin) override {
+        auto found = std::find(loaded_plugins_.begin(), loaded_plugins_.end(), plugin);
         assert(found != loaded_plugins_.end());
         loaded_plugins_.erase(found);
+        plugin->GetVst3PluginDestructionListenerService().RemoveListener(this);
     }
     
     UInt32 GetNumLoadedPlugins() const {
@@ -334,11 +336,10 @@ std::unique_ptr<Vst3Plugin>
 {
     auto p = CreatePlugin(pimpl_->GetFactory(),
                           pimpl_->GetFactoryInfo(),
-                          GetComponentInfo(index),
-                          [this](Vst3Plugin const *p) { pimpl_->OnVst3PluginIsDestructed(p); }
+                          GetComponentInfo(index)
                           );
-    pimpl_->OnVst3PluginIsCreated(p.get());
     
+    pimpl_->OnAfterConstruction(p.get());
     return p;
 }