launch_daemon: Added support for external events.

* Other apps can register events, and the launch_daemon can act on them
  when they are triggered.

headers/private/app/LaunchDaemonDefs.h

@@ -22,12 +22,15 @@ namespace BPrivate {
 #define B_LAUNCH_DAEMON_PORT_NAME "system:launch_daemon"
 
 
-// message constants
+// Message constants
 enum {
 	B_GET_LAUNCH_DATA			= 'lnda',
 	B_LAUNCH_TARGET				= 'lntg',
 	B_LAUNCH_SESSION			= 'lnse',
 	B_REGISTER_SESSION_DAEMON	= 'lnrs',
+	B_REGISTER_LAUNCH_EVENT		= 'lnre',
+	B_UNREGISTER_LAUNCH_EVENT	= 'lnue',
+	B_NOTIFY_LAUNCH_EVENT		= 'lnne',
 };
 
 

headers/private/app/LaunchRoster.h

@@ -30,12 +30,21 @@ class BLaunchRoster {
 
 			status_t			StartSession(const char* login);
 
+			status_t			RegisterEvent(const BMessenger& source,
+									const char* name);
+			status_t			UnregisterEvent(const BMessenger& source,
+									const char* name);
+			status_t			NotifyEvent(const BMessenger& source,
+									const char* name);
+
 	class Private;
 
 private:
 	friend class Private;
 
 			void				_InitMessenger();
+			status_t			_UpdateEvent(uint32 what,
+									const BMessenger& source, const char* name);
 
 private:
 			BMessenger			fMessenger;

src/kits/app/LaunchRoster.cpp

@@ -208,6 +208,27 @@ BLaunchRoster::StartSession(const char* login)
 }
 
 
+status_t
+BLaunchRoster::RegisterEvent(const BMessenger& source, const char* name)
+{
+	return _UpdateEvent(B_REGISTER_LAUNCH_EVENT, source, name);
+}
+
+
+status_t
+BLaunchRoster::UnregisterEvent(const BMessenger& source, const char* name)
+{
+	return _UpdateEvent(B_UNREGISTER_LAUNCH_EVENT, source, name);
+}
+
+
+status_t
+BLaunchRoster::NotifyEvent(const BMessenger& source, const char* name)
+{
+	return _UpdateEvent(B_NOTIFY_LAUNCH_EVENT, source, name);
+}
+
+
 void
 BLaunchRoster::_InitMessenger()
 {
@@ -219,3 +240,33 @@ BLaunchRoster::_InitMessenger()
 			B_PREFERRED_TOKEN);
 	}
 }
+
+
+status_t
+BLaunchRoster::_UpdateEvent(uint32 what, const BMessenger& source,
+	const char* name)
+{
+	if (be_app == NULL || name == NULL || name[0] == '\0')
+		return B_BAD_VALUE;
+
+	BMessage request(what);
+	status_t status = request.AddInt32("user", getuid());
+	if (status == B_OK)
+		status = request.AddMessenger("source", source);
+	if (status == B_OK)
+		status = request.AddString("owner", be_app->Signature());
+	if (status == B_OK)
+		status = request.AddString("name", name);
+	if (status != B_OK)
+		return status;
+
+	// send the request
+	BMessage result;
+	status = fMessenger.SendMessage(&request, &result);
+
+	// evaluate the reply
+	if (status == B_OK)
+		status = result.what;
+
+	return status;
+}

src/servers/launch/Events.cpp

@@ -73,6 +73,26 @@ class DemandEvent : public Event {
 };
 
 
+class ExternalEvent : public Event {
+public:
+								ExternalEvent(Event* parent, const char* name,
+									const BMessage& args);
+
+			const BString&		Name() const;
+			bool				Resolve();
+
+	virtual	status_t			Register(EventRegistrator& registrator) const;
+	virtual	void				Unregister(EventRegistrator& registrator) const;
+
+	virtual	BString				ToString() const;
+
+private:
+			BString				fName;
+			BStringList			fArguments;
+			bool				fResolved;
+};
+
+
 class FileCreatedEvent : public Event {
 public:
 								FileCreatedEvent(Event* parent,
@@ -104,7 +124,7 @@ create_event(Event* parent, const char* name, const BMessenger* target,
 	if (strcmp(name, "file_created") == 0)
 		return new FileCreatedEvent(parent, args);
 
-	return NULL;
+	return new ExternalEvent(parent, name, args);
 }
 
 
@@ -353,6 +373,62 @@ DemandEvent::ToString() const
 }
 
 
+// #pragma mark - External event
+
+
+ExternalEvent::ExternalEvent(Event* parent, const char* name,
+	const BMessage& args)
+	:
+	Event(parent),
+	fName(name),
+	fResolved(false)
+{
+	const char* argument;
+	for (int32 index = 0; args.FindString("args", index, &argument) == B_OK;
+			index++) {
+		fArguments.Add(argument);
+	}
+}
+
+
+const BString&
+ExternalEvent::Name() const
+{
+	return fName;
+}
+
+
+bool
+ExternalEvent::Resolve()
+{
+	if (fResolved)
+		return false;
+
+	fResolved = true;
+	return true;
+}
+
+
+status_t
+ExternalEvent::Register(EventRegistrator& registrator) const
+{
+	return B_OK;
+}
+
+
+void
+ExternalEvent::Unregister(EventRegistrator& registrator) const
+{
+}
+
+
+BString
+ExternalEvent::ToString() const
+{
+	return fName;
+}
+
+
 // #pragma mark - file_created
 
 
@@ -416,6 +492,53 @@ Events::AddOnDemand(Event* event)
 }
 
 
+/*static*/ bool
+Events::ResolveRegisteredEvent(Event* event, const char* name)
+{
+	if (event == NULL)
+		return false;
+
+	if (EventContainer* container = dynamic_cast<EventContainer*>(event)) {
+		for (int32 index = 0; index < container->Events().CountItems();
+				index++) {
+			Event* event = container->Events().ItemAt(index);
+			if (ExternalEvent* external = dynamic_cast<ExternalEvent*>(event)) {
+				if (external->Name() == name && external->Resolve())
+					return true;
+			} else if (dynamic_cast<EventContainer*>(event) != NULL) {
+				if (ResolveRegisteredEvent(event, name))
+					return true;
+			}
+		}
+	}
+	return false;
+}
+
+
+/*static*/ void
+Events::TriggerRegisteredEvent(Event* event, const char* name)
+{
+	if (event == NULL)
+		return;
+
+	if (EventContainer* container = dynamic_cast<EventContainer*>(event)) {
+		for (int32 index = 0; index < container->Events().CountItems();
+				index++) {
+			Event* event = container->Events().ItemAt(index);
+			if (ExternalEvent* external = dynamic_cast<ExternalEvent*>(event)) {
+				if (external->Name() == name) {
+					external->Trigger();
+					return;
+				}
+			} else if (dynamic_cast<EventContainer*>(event) != NULL) {
+				TriggerRegisteredEvent(event, name);
+			}
+		}
+	}
+	return;
+}
+
+
 /*static*/ bool
 Events::TriggerDemand(Event* event)
 {

src/servers/launch/Events.h

@@ -53,6 +53,10 @@ class Events {
 	static	Event*			FromMessage(const BMessenger& target,
 								const BMessage& message);
 	static	Event*			AddOnDemand(Event* event);
+	static	bool			ResolveRegisteredEvent(Event* event,
+								const char* name);
+	static	void			TriggerRegisteredEvent(Event* event,
+								const char* name);
 	static	bool			TriggerDemand(Event* event);
 };