libcamera: bound_method: Support connection types

Support all connection types in the BoundMethodBase::activePack()
method. To support this, add a semaphore to the InvokeMessage to signal
delivery.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/libcamera/include/message.h

@@ -15,6 +15,7 @@ namespace libcamera {
 
 class BoundMethodBase;
 class Object;
+class Semaphore;
 class Thread;
 
 class Message
@@ -48,14 +49,18 @@ class InvokeMessage : public Message
 {
 public:
 	InvokeMessage(BoundMethodBase *method, void *pack,
+		      Semaphore *semaphore = nullptr,
 		      bool deleteMethod = false);
 	~InvokeMessage();
 
+	Semaphore *semaphore() const { return semaphore_; }
+
 	void invoke();
 
 private:
 	BoundMethodBase *method_;
 	void *pack_;
+	Semaphore *semaphore_;
 	bool deleteMethod_;
 };