libcamera: Document thread-safety attributes of core classes

Define the thread-safety attributes of the classes and methods that are
either thread-safe or thread-bound. The CameraManager, Camera and
PipelineHandler will be addressed separately.

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

src/libcamera/object.cpp

@@ -110,6 +110,8 @@ Object::~Object()
  * Messages are delivered through the thread's event loop. If the thread is not
  * running its event loop the message will not be delivered until the event
  * loop gets started.
+ *
+ * \context This function is \threadsafe.
  */
 void Object::postMessage(std::unique_ptr<Message> msg)
 {
@@ -162,6 +164,8 @@ void Object::message(Message *msg)
  * are passed untouched. The caller shall ensure that any pointer argument
  * remains valid until the method is invoked.
  *
+ * \context This function is \threadsafe.
+ *
  * \return For connection types ConnectionTypeDirect and
  * ConnectionTypeBlocking, return the return value of the invoked method. For
  * connection type ConnectionTypeQueued, return a default-constructed R value.
@@ -170,6 +174,7 @@ void Object::message(Message *msg)
 /**
  * \fn Object::thread()
  * \brief Retrieve the thread the object is bound to
+ * \context This function is \threadsafe.
  * \return The thread the object is bound to
  */
 
@@ -178,8 +183,7 @@ void Object::message(Message *msg)
  * \param[in] thread The target thread
  *
  * This method moves the object and all its children from the current thread to
- * the new \a thread. It shall be called from the thread in which the object
- * currently lives, otherwise the behaviour is undefined.
+ * the new \a thread.
  *
  * Before the object is moved, a Message::ThreadMoveMessage message is sent to
  * it. The message() method can be reimplement in derived classes to be notified
@@ -187,6 +191,8 @@ void Object::message(Message *msg)
  *
  * Moving an object that has a parent is not allowed, and causes undefined
  * behaviour.
+ *
+ * \context This function is thread-bound.
  */
 void Object::moveToThread(Thread *thread)
 {