libcamera: signal: Support cross-thread signals

Allow signals to cross thread boundaries by posting them to the
recipient through messages instead of calling the slot directly when the
recipient lives in a different thread.

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

1 files changed, 22 insertions, 0 deletions

diff --git a/src/libcamera/message.cpp b/src/libcamera/message.cpp
index 5bb17ae2..0580c105 100644
--- a/src/libcamera/message.cpp
+++ b/src/libcamera/message.cpp
@@ -68,4 +68,26 @@ Message::~Message()
  * \return The message receiver
  */
 
+/**
+ * \class SignalMessage
+ * \brief A message carrying a Signal across threads
+ */
+
+/**
+ * \fn SignalMessage::SignalMessage()
+ * \brief Construct a SignalMessage
+ * \param[in] slot The slot that the signal targets
+ * \param[in] pack The signal arguments
+ */
+
+/**
+ * \var SignalMessage::slot_
+ * \brief The slot that the signal targets
+ */
+
+/**
+ * \var SignalMessage::pack_
+ * \brief The signal arguments
+ */
+
 }; /* namespace libcamera */