Refactored the Component class.

base/application.cpp

@@ -60,14 +60,6 @@ Application::~Application(void)
 {
 	m_ShuttingDown = true;
 
-	/* stop all components */
-	Component::Ptr component;
-	BOOST_FOREACH(tie(tuples::ignore, component), m_Components) {
-		component->Stop();
-	}
-
-	m_Components.clear();
-
 #ifdef _WIN32
 	WSACleanup();
 #endif /* _WIN32 */
@@ -101,6 +93,8 @@ void Application::RunEventLoop(void)
 
 		Event::ProcessEvents(boost::get_system_time() + boost::posix_time::seconds(sleep));
 	}
+
+	Component::UnloadAll();
 }
 
 /**
@@ -112,103 +106,6 @@ void Application::Shutdown(void)
 	m_ShuttingDown = true;
 }
 
-/**
- * Loads a component from a shared library.
- *
- * @param path The path of the component library.
- * @param componentConfig The configuration for the component.
- * @returns The component.
- */
-Component::Ptr Application::LoadComponent(const string& path,
-    const ConfigObject::Ptr& componentConfig)
-{
-	Component::Ptr component;
-	Component *(*pCreateComponent)();
-
-	assert(Application::IsMainThread());
-
-	Logger::Write(LogInformation, "base", "Loading component '" + path + "'");
-
-#ifdef _WIN32
-	HMODULE hModule = LoadLibrary(path.c_str());
-
-	if (hModule == NULL)
-		throw_exception(Win32Exception("LoadLibrary('" + path + "') failed", GetLastError()));
-#else /* _WIN32 */
-	lt_dlhandle hModule = lt_dlopen(path.c_str());
-
-	if (hModule == NULL) {
-		throw_exception(runtime_error("Could not load module '" + path + "': " +  lt_dlerror()));
-	}
-#endif /* _WIN32 */
-
-#ifdef _WIN32
-	pCreateComponent = (CreateComponentFunction)GetProcAddress(hModule,
-	    "CreateComponent");
-#else /* _WIN32 */
-#	ifdef __GNUC__
-	/* suppress compiler warning for void * cast */
-	__extension__
-#	endif
-	pCreateComponent = (CreateComponentFunction)lt_dlsym(hModule,
-	    "CreateComponent");
-#endif /* _WIN32 */
-
-	if (pCreateComponent == NULL)
-		throw_exception(runtime_error("Loadable module does not contain "
-		    "CreateComponent function"));
-
-	component = Component::Ptr(pCreateComponent());
-	component->SetConfig(componentConfig);
-	RegisterComponent(component);
-	return component;
-}
-
-/**
- * Registers a component object and starts it.
- *
- * @param component The component.
- */
-void Application::RegisterComponent(const Component::Ptr& component)
-{
-	m_Components[component->GetName()] = component;
-
-	component->Start();
-}
-
-/**
- * Unregisters a component object and stops it.
- *
- * @param component The component.
- */
-void Application::UnregisterComponent(const Component::Ptr& component)
-{
-	string name = component->GetName();
-
-	Logger::Write(LogInformation, "base", "Unloading component '" + name + "'");
-	map<string, Component::Ptr>::iterator i = m_Components.find(name);
-	if (i != m_Components.end())
-		m_Components.erase(i);
-		
-	component->Stop();
-}
-
-/**
- * Finds a loaded component by name.
- *
- * @param name The name of the component.
- * @returns The component or a null pointer if the component could not be found.
- */
-Component::Ptr Application::GetComponent(const string& name) const
-{
-	map<string, Component::Ptr>::const_iterator i = m_Components.find(name);
-
-	if (i == m_Components.end())
-		return Component::Ptr();
-
-	return i->second;
-}
-
 /**
  * Retrieves the full path of the executable.
  *
@@ -276,20 +173,6 @@ string Application::GetExePath(void) const
 	return result;
 }
 
-/**
- * Adds a directory to the component search path.
- *
- * @param componentDirectory The directory.
- */
-void Application::AddComponentSearchDir(const string& componentDirectory)
-{
-#ifdef _WIN32
-	SetDllDirectory(componentDirectory.c_str());
-#else /* _WIN32 */
-	lt_dladdsearchdir(componentDirectory.c_str());
-#endif /* _WIN32 */
-}
-
 /**
  * Retrieves the debugging mode of the application.
  *

base/application.h

@@ -45,13 +45,6 @@ public:
 
 	static void Shutdown(void);
 
-	shared_ptr<Component> LoadComponent(const string& path,
-	    const ConfigObject::Ptr& componentConfig);
-	void RegisterComponent(const shared_ptr<Component>& component);
-	void UnregisterComponent(const shared_ptr<Component>& component);
-	shared_ptr<Component> GetComponent(const string& name) const;
-	void AddComponentSearchDir(const string& componentDirectory);
-
 	static bool IsDebugging(void);
 
 	static bool IsMainThread(void);
@@ -68,8 +61,6 @@ private:
 
 	static bool m_ShuttingDown; /**< Whether the application is in the process of
 				  shutting down. */
-	map< string, shared_ptr<Component> > m_Components; /**< Components that
-					were loaded by the application. */
 	vector<string> m_Arguments; /**< Command-line arguments */
 	FILE *m_PidFile; /**< The PID file */
 	static bool m_Debugging; /**< Whether debugging is enabled. */

base/component.cpp

@@ -21,14 +21,152 @@
 
 using namespace icinga;
 
+map<string, Component::Ptr> Component::m_Components;
+
 /**
- * Sets the configuration for this component.
+ * Loads a component from a shared library.
  *
- * @param componentConfig The configuration.
+ * @param name The name of the component.
+ * @param componentConfig The configuration for the component.
  */
-void Component::SetConfig(const ConfigObject::Ptr& componentConfig)
+void Component::Load(const string& name, const ConfigObject::Ptr& config)
 {
-	m_Config = componentConfig;
+	assert(Application::IsMainThread());
+
+	string path;
+#ifdef _WIN32
+	path = name + ".dll";
+#else /* _WIN32 */
+	path = name + ".la";
+#endif /* _WIN32 */
+
+	Logger::Write(LogInformation, "base", "Loading component '" + name + "' (using library '" + path + "')");
+
+#ifdef _WIN32
+	HMODULE hModule = LoadLibrary(path.c_str());
+
+	if (hModule == NULL)
+		throw_exception(Win32Exception("LoadLibrary('" + path + "') failed", GetLastError()));
+#else /* _WIN32 */
+	lt_dlhandle hModule = lt_dlopen(path.c_str());
+
+	if (hModule == NULL) {
+		throw_exception(runtime_error("Could not load module '" + path + "': " +  lt_dlerror()));
+	}
+#endif /* _WIN32 */
+
+	CreateComponentFunction pCreateComponent;
+
+#ifdef _WIN32
+	pCreateComponent = (CreateComponentFunction)GetProcAddress(hModule,
+	    "CreateComponent");
+#else /* _WIN32 */
+#	ifdef __GNUC__
+	/* suppress compiler warning for void * cast */
+	__extension__
+#	endif
+	pCreateComponent = (CreateComponentFunction)lt_dlsym(hModule,
+	    "CreateComponent");
+#endif /* _WIN32 */
+
+	Component::Ptr component;
+
+	try {
+		if (pCreateComponent == NULL)
+			throw_exception(runtime_error("Loadable module does not contain "
+			    "CreateComponent function"));
+
+		component = Component::Ptr(pCreateComponent());
+
+		if (!component)
+			throw_exception(runtime_error("CreateComponent function returned NULL."));
+	} catch (...) {
+#ifdef _WIN32
+		FreeLibrary(hModule);
+#else /* _WIN32 */
+		lt_dlclose(hModule);
+#endif /* _WIN32 */
+		throw;
+	}
+
+	component->m_Name = name;
+	component->m_Config = config;
+	component->m_ModuleHandle = hModule;
+
+	try {
+		m_Components[name] = component;
+		component->Start();
+	} catch (...) {
+		m_Components.erase(name);
+		throw;
+	}
+}
+
+void Component::Unload(const string& componentName)
+{
+	map<string, Component::Ptr>::iterator it;
+	
+	it = m_Components.find(componentName);
+
+	if (it == m_Components.end())
+		return;
+
+	Logger::Write(LogInformation, "base", "Unloading component '" + componentName + "'");
+
+	Component::Ptr component = it->second;
+	component->Stop();
+
+	m_Components.erase(it);
+
+	/** Unfortunatelly we can't safely unload the DLL/shared library
+	 * here because there could still be objects that use the library. */
+}
+
+void Component::UnloadAll(void)
+{
+	Logger::Write(LogInformation, "base", "Unloading all components");
+
+	while (!m_Components.empty()) {
+		string name = m_Components.begin()->first;
+		Unload(name);
+	}
+}
+
+/**
+ * Adds a directory to the component search path.
+ *
+ * @param componentDirectory The directory.
+ */
+void Component::AddSearchDir(const string& componentDirectory)
+{
+#ifdef _WIN32
+	SetDllDirectory(componentDirectory.c_str());
+#else /* _WIN32 */
+	lt_dladdsearchdir(componentDirectory.c_str());
+#endif /* _WIN32 */
+}
+
+/**
+ * Constructor for the Component class.
+ */
+Component::Component(void)
+	: m_ModuleHandle(0)
+{ }
+
+/**
+ * Destructor for the Component class.
+ */
+Component::~Component(void)
+{ }
+
+/**
+ * Retrieves the name of the component.
+ *
+ * @returns Name of the component.
+ */
+string Component::GetName(void) const
+{
+	return m_Name;
 }
 
 /**
@@ -40,3 +178,19 @@ ConfigObject::Ptr Component::GetConfig(void) const
 {
 	return m_Config;
 }
+
+/**
+ * Starts the component.
+ */
+void Component::Start(void)
+{
+	/* Nothing to do in the default implementation. */
+}
+
+/**
+ * Stops the component.
+ */
+void Component::Stop(void)
+{
+	/* Nothing to do in the default implementation. */
+}

base/component.h

@@ -35,15 +35,35 @@ public:
 	typedef shared_ptr<Component> Ptr;
 	typedef weak_ptr<Component> WeakPtr;
 
-	void SetConfig(const ConfigObject::Ptr& componentConfig);
+	Component(void);
+	virtual ~Component(void);
+
 	ConfigObject::Ptr GetConfig(void) const;
 
-	virtual string GetName(void) const = 0;
+	virtual void Start(void);
-	virtual void Start(void) = 0;
+	virtual void Stop(void);
-	virtual void Stop(void) = 0;
+
+	string GetName(void) const;
+
+	static void Load(const string& name, const ConfigObject::Ptr& config);
+	static void Unload(const Component::Ptr& component);
+	static void Unload(const string& componentName);
+	static void UnloadAll(void);
+	static Component::Ptr GetByName(const string& name);
+	static void AddSearchDir(const string& componentDirectory);
 
 private:
+	string m_Name;
 	ConfigObject::Ptr m_Config;
+
+#ifdef _WIN32
+	HMODULE m_ModuleHandle;
+#else /* _WIN32 */
+	lt_dlhandle m_ModuleHandle;
+#endif /* _WIN32 */
+
+	static map<string, Component::Ptr> m_Components; /**< Components that
+					were loaded by the application. */
 };
 
 typedef Component *(*CreateComponentFunction)(void);

icinga/icingaapplication.cpp

@@ -133,7 +133,7 @@ int IcingaApplication::Main(const vector<string>& args)
 	}
 
 	string componentDirectory = Utility::DirName(GetExePath()) + "/../lib/icinga2";
-	AddComponentSearchDir(componentDirectory);
+	Component::AddSearchDir(componentDirectory);
 
 	/* register handler for 'component' config objects */
 	static ConfigObject::Set::Ptr componentObjects = boost::make_shared<ConfigObject::Set>(ConfigObject::GetAllObjects(), ConfigObject::MakeTypePredicate("component"));
@@ -219,16 +219,7 @@ void IcingaApplication::NewComponentHandler(const ConfigObject::Ptr& object)
 	if (!object->IsLocal())
 		throw_exception(runtime_error("'component' objects must be 'local'"));
 
-	string path;
+	Component::Load(object->GetName(), object);
-	if (!object->GetProperty("path", &path)) {
-#ifdef _WIN32
-		path = object->GetName() + ".dll";
-#else /* _WIN32 */
-		path = object->GetName() + ".la";
-#endif /* _WIN32 */
-	}
-
-	LoadComponent(path, object);
 }
 
 void IcingaApplication::NewLogHandler(const ConfigObject::Ptr& object)
@@ -290,8 +281,7 @@ IcingaApplication::Ptr IcingaApplication::GetInstance(void)
 
 void IcingaApplication::DeletedComponentHandler(const ConfigObject::Ptr& object)
 {
-	Component::Ptr component = GetComponent(object->GetName());
+	Component::Unload(object->GetName());
-	UnregisterComponent(component);
 }
 
 string IcingaApplication::GetCertificateFile(void) const