libcamera: object: Add an asynchronous method invocation method

Add a helper invokeMethod() to the Object class that allows asynchrnous
invocation of any method of an Object instance. Asynchronous invocation
occurs when control returns to the event dispatcher of the target
object's thread, in the context of that thread.

To support this, generalise the SignalMessage implementation to support
automatic deletion of the associated BoundMethod, and rename the message
to InvokeMessage to reflect the more generic purpose.

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

1 files changed, 11 insertions, 6 deletions

diff --git a/src/libcamera/include/message.h b/src/libcamera/include/message.h
index b4670c0e..92717e31 100644
--- a/src/libcamera/include/message.h
+++ b/src/libcamera/include/message.h
@@ -9,6 +9,8 @@
 
 #include <atomic>
 
+#include <libcamera/bound_method.h>
+
 namespace libcamera {
 
 class BoundMethodBase;
@@ -20,7 +22,7 @@ class Message
 public:
 	enum Type {
 		None = 0,
-		SignalMessage = 1,
+		InvokeMessage = 1,
 		UserMessage = 1000,
 	};
 
@@ -41,16 +43,19 @@ private:
 	static std::atomic_uint nextUserType_;
 };
 
-class SignalMessage : public Message
+class InvokeMessage : public Message
 {
 public:
-	SignalMessage(BoundMethodBase *method, void *pack)
-		: Message(Message::SignalMessage), method_(method), pack_(pack)
-	{
-	}
+	InvokeMessage(BoundMethodBase *method, void *pack,
+		      bool deleteMethod = false);
+	~InvokeMessage();
+
+	void invoke();
 
+private:
 	BoundMethodBase *method_;
 	void *pack_;
+	bool deleteMethod_;
 };
 
 } /* namespace libcamera */