mirror of
https://git.libcamera.org/libcamera/libcamera.git
synced 2025-07-23 00:25:07 +03:00
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>
This commit is contained in:
parent
01b930964a
commit
cc3ae13d9e
5 changed files with 136 additions and 8 deletions
|
@ -10,6 +10,7 @@
|
|||
namespace libcamera {
|
||||
|
||||
class Object;
|
||||
class SlotBase;
|
||||
class Thread;
|
||||
|
||||
class Message
|
||||
|
@ -17,6 +18,7 @@ class Message
|
|||
public:
|
||||
enum Type {
|
||||
None = 0,
|
||||
SignalMessage = 1,
|
||||
};
|
||||
|
||||
Message(Type type);
|
||||
|
@ -32,6 +34,18 @@ private:
|
|||
Object *receiver_;
|
||||
};
|
||||
|
||||
class SignalMessage : public Message
|
||||
{
|
||||
public:
|
||||
SignalMessage(SlotBase *slot, void *pack)
|
||||
: Message(Message::SignalMessage), slot_(slot), pack_(pack)
|
||||
{
|
||||
}
|
||||
|
||||
SlotBase *slot_;
|
||||
void *pack_;
|
||||
};
|
||||
|
||||
} /* namespace libcamera */
|
||||
|
||||
#endif /* __LIBCAMERA_MESSAGE_H__ */
|
||||
|
|
|
@ -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 */
|
||||
|
|
|
@ -10,6 +10,7 @@
|
|||
#include <libcamera/signal.h>
|
||||
|
||||
#include "log.h"
|
||||
#include "message.h"
|
||||
#include "thread.h"
|
||||
|
||||
/**
|
||||
|
@ -32,6 +33,10 @@ namespace libcamera {
|
|||
* This allows implementing easy message passing between threads by inheriting
|
||||
* from the Object class.
|
||||
*
|
||||
* Object slots connected to signals will also run in the context of the
|
||||
* object's thread, regardless of whether the signal is emitted in the same or
|
||||
* in another thread.
|
||||
*
|
||||
* \sa Message, Signal, Thread
|
||||
*/
|
||||
|
||||
|
@ -82,6 +87,16 @@ void Object::postMessage(std::unique_ptr<Message> msg)
|
|||
*/
|
||||
void Object::message(Message *msg)
|
||||
{
|
||||
switch (msg->type()) {
|
||||
case Message::SignalMessage: {
|
||||
SignalMessage *smsg = static_cast<SignalMessage *>(msg);
|
||||
smsg->slot_->invokePack(smsg->pack_);
|
||||
break;
|
||||
}
|
||||
|
||||
default:
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
|
@ -7,6 +7,10 @@
|
|||
|
||||
#include <libcamera/signal.h>
|
||||
|
||||
#include "message.h"
|
||||
#include "thread.h"
|
||||
#include "utils.h"
|
||||
|
||||
/**
|
||||
* \file signal.h
|
||||
* \brief Signal & slot implementation
|
||||
|
@ -42,8 +46,30 @@ namespace libcamera {
|
|||
* to the same slot. Duplicate connections between a signal and a slot are
|
||||
* allowed and result in the slot being called multiple times for the same
|
||||
* signal emission.
|
||||
*
|
||||
* When a slot belongs to an instance of the Object class, the slot is called
|
||||
* in the context of the thread that the object is bound to. If the signal is
|
||||
* emitted from the same thread, the slot will be called synchronously, before
|
||||
* Signal::emit() returns. If the signal is emitted from a different thread,
|
||||
* the slot will be called asynchronously from the object's thread's event
|
||||
* loop, after the Signal::emit() method returns, with a copy of the signal's
|
||||
* arguments. The emitter shall thus ensure that any pointer or reference
|
||||
* passed through the signal will remain valid after the signal is emitted.
|
||||
*/
|
||||
|
||||
void SlotBase::activatePack(void *pack)
|
||||
{
|
||||
Object *obj = static_cast<Object *>(obj_);
|
||||
|
||||
if (Thread::current() == obj->thread()) {
|
||||
invokePack(pack);
|
||||
} else {
|
||||
std::unique_ptr<Message> msg =
|
||||
utils::make_unique<SignalMessage>(this, pack);
|
||||
obj->postMessage(std::move(msg));
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* \fn Signal::connect(T *object, void(T::*func)(Args...))
|
||||
* \brief Connect the signal to a member function slot
|
||||
|
|
Loading…
Add table
Add a link
Reference in a new issue