Allow dynrefs to have an OnCapture() hook

2 files changed, 26 insertions, 2 deletions

diff --git a/include/dynref.h b/include/dynref.h
index a3d2f9966..2069a87eb 100644
--- a/include/dynref.h
+++ b/include/dynref.h
@@ -24,8 +24,18 @@
 
 class CoreExport dynamic_reference_base : public interfacebase, public insp::intrusive_list_node<dynamic_reference_base>
 {
+ public:
+	class CaptureHook
+	{
+	 public:
+		/** Called when the target of the dynamic_reference has been acquired
+		 */
+		virtual void OnCapture() = 0;
+	};
+
  private:
 	std::string name;
+	CaptureHook* hook;
 	void resolve();
  protected:
 	ServiceProvider* value;
@@ -35,6 +45,12 @@ class CoreExport dynamic_reference_base : public interfacebase, public insp::int
 	~dynamic_reference_base();
 	inline const std::string& GetProvider() { return name; }
 	void SetProvider(const std::string& newname);
+
+	/** Set handler to call when the target object becomes available
+	 * @param h Handler to call
+	 */
+	void SetCaptureHook(CaptureHook* h) { hook = h; }
+
 	void check();
 	operator bool() { return (value != NULL); }
 	static void reset_all();
diff --git a/src/modules.cpp b/src/modules.cpp
index 6510c9423..55d41674b 100644
--- a/src/modules.cpp
+++ b/src/modules.cpp
@@ -655,7 +655,7 @@ ServiceProvider* ModuleManager::FindService(ServiceType type, const std::string&
 }
 
 dynamic_reference_base::dynamic_reference_base(Module* Creator, const std::string& Name)
-	: name(Name), value(NULL), creator(Creator)
+	: name(Name), hook(NULL), value(NULL), creator(Creator)
 {
 	if (!dynrefs)
 		dynrefs = new insp::intrusive_list<dynamic_reference_base>;
@@ -688,7 +688,15 @@ void dynamic_reference_base::resolve()
 	// to ensure a dynref with the same name as another one resolves to the same object
 	std::multimap<std::string, ServiceProvider*>::iterator i = ServerInstance->Modules.DataProviders.lower_bound(name);
 	if ((i != ServerInstance->Modules.DataProviders.end()) && (i->first == this->name))
-		value = static_cast<DataProvider*>(i->second);
+	{
+		ServiceProvider* newvalue = i->second;
+		if (value != newvalue)
+		{
+			value = newvalue;
+			if (hook)
+				hook->OnCapture();
+		}
+	}
 	else
 		value = NULL;
 }