[PATCH 1/5] libcamera: Allow pipeline to provide a Private request

Jacopo Mondi jacopo.mondi at ideasonboard.com
Tue Mar 5 12:28:14 CET 2024


Hi Dan

On Tue, Mar 05, 2024 at 11:10:02AM +0000, Dan Scally wrote:
> Hi Jacopo
>
> On 21/02/2024 17:40, Jacopo Mondi wrote:
> > In order to allow each pipeline handler to create a Request::Private
> > derived class to store ancillary data associated with a capture request,
> > modify the way a Request is created by the PipelineHandler base class.
> >
> > Introduce a virtual PipelineHandler::createRequestDevice() that pipeline
> > handler implementation can optionally override to provide a custom
> > private data type to initialize the Request with.
> >
> > As we can't anymore create a Request without going through an active
> > camera, drop the queueRequest() checks from the Camera statemachine
> > test.
> >
> > Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> > ---
> >   include/libcamera/internal/pipeline_handler.h |  5 ++-
> >   include/libcamera/request.h                   |  3 +-
> >   src/libcamera/camera.cpp                      |  8 +---
> >   src/libcamera/pipeline_handler.cpp            | 38 ++++++++++++++++---
> >   src/libcamera/request.cpp                     | 15 +++++---
> >   test/camera/statemachine.cpp                  | 12 ------
> >   6 files changed, 50 insertions(+), 31 deletions(-)
> >
> > diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h
> > index c96944f4ecc4..bbe74f22e5ae 100644
> > --- a/include/libcamera/internal/pipeline_handler.h
> > +++ b/include/libcamera/internal/pipeline_handler.h
> > @@ -21,6 +21,7 @@
> >   #include <libcamera/stream.h>
> >   #include "libcamera/internal/ipa_proxy.h"
> > +#include "libcamera/internal/request.h"
> >   namespace libcamera {
> > @@ -59,7 +60,7 @@ public:
> >   	void stop(Camera *camera);
> >   	bool hasPendingRequests(const Camera *camera) const;
> > -	void registerRequest(Request *request);
> > +	std::unique_ptr<Request> createRequest(Camera *camera, uint64_t cookie);
> >   	void queueRequest(Request *request);
> >   	bool completeBuffer(Request *request, FrameBuffer *buffer);
> > @@ -74,6 +75,8 @@ protected:
> >   	void registerCamera(std::shared_ptr<Camera> camera);
> >   	void hotplugMediaDevice(MediaDevice *media);
> > +	virtual std::unique_ptr<Request> createRequestDevice(Camera *camera,
> > +							     uint64_t cookie);
> >   	virtual int queueRequestDevice(Camera *camera, Request *request) = 0;
> >   	virtual void stopDevice(Camera *camera) = 0;
> > diff --git a/include/libcamera/request.h b/include/libcamera/request.h
> > index dffde1536cad..e16e61a93873 100644
> > --- a/include/libcamera/request.h
> > +++ b/include/libcamera/request.h
> > @@ -45,9 +45,10 @@ public:
> >   	using BufferMap = std::map<const Stream *, FrameBuffer *>;
> > -	Request(Camera *camera, uint64_t cookie = 0);
> > +	Request(std::unique_ptr<Private> d, uint64_t cookie = 0);
> >   	~Request();
> > +	static std::unique_ptr<Request> create(std::unique_ptr<Private> d, uint64_t);
> >   	void reuse(ReuseFlag flags = Default);
> >   	ControlList &controls() { return *controls_; }
> > diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
> > index a71dc933b911..b7053576fe42 100644
> > --- a/src/libcamera/camera.cpp
> > +++ b/src/libcamera/camera.cpp
> > @@ -1236,12 +1236,8 @@ std::unique_ptr<Request> Camera::createRequest(uint64_t cookie)
> >   	if (ret < 0)
> >   		return nullptr;
> > -	std::unique_ptr<Request> request = std::make_unique<Request>(this, cookie);
> > -
> > -	/* Associate the request with the pipeline handler. */
> > -	d->pipe_->registerRequest(request.get());
> > -
> > -	return request;
> > +	/* Create a Request from the pipeline handler. */
> > +	return d->pipe_->createRequest(this, cookie);
> >   }
> >   /**
> > diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
> > index 29e0c98a6db5..f2a8cdac0408 100644
> > --- a/src/libcamera/pipeline_handler.cpp
> > +++ b/src/libcamera/pipeline_handler.cpp
> > @@ -371,20 +371,25 @@ bool PipelineHandler::hasPendingRequests(const Camera *camera) const
> >   }
> >   /**
> > - * \fn PipelineHandler::registerRequest()
> > - * \brief Register a request for use by the pipeline handler
> > - * \param[in] request The request to register
> > + * \fn PipelineHandler::createRequest()
> > + * \brief Create a request and register it for use by the pipeline handler
> > + * \param[in] camera The camera the Request belongs to
> > + * \param[in] cookie The Request unique identifier
> >    *
> > - * This function is called when the request is created, and allows the pipeline
> > - * handler to perform any one-time initialization it requries for the request.
> > + * This function is called to create a Request by calling createRequestDevice()
> > + * which can be optionally provided by the PipelineHandler derived classes.
> >    */
> > -void PipelineHandler::registerRequest(Request *request)
> > +std::unique_ptr<Request> PipelineHandler::createRequest(Camera *camera, uint64_t cookie)
> >   {
> > +	std::unique_ptr<Request> request = createRequestDevice(camera, cookie);
> > +
> >   	/*
> >   	 * Connect the request prepared signal to notify the pipeline handler
> >   	 * when a request is ready to be processed.
> >   	 */
> >   	request->_d()->prepared.connect(this, &PipelineHandler::doQueueRequests);
> > +
> > +	return request;
> >   }
> >   /**
> > @@ -462,6 +467,27 @@ void PipelineHandler::doQueueRequests()
> >   	}
> >   }
> > +/**
> > + * \brief Create a Request from the pipeline handler
> > + * \param[in] camera The camera the Request belongs to
> > + * \param[in] cookie The Request unique identifier
> > + *
> > + * A virtual function that PipelineHandler derived classes are free to override
> > + * in order to initialize a Request with a custom Request::Private derived
> > + * class.
> > + *
> > + * This is the base class implementation that use Request::Private to
> > + * initialize the Request.
> > + *
> > + * \return A unique pointer to a newly created Request
> > + */
> > +std::unique_ptr<Request>
> > +PipelineHandler::createRequestDevice(Camera *camera, uint64_t cookie)
> > +{
> > +	auto d = std::make_unique<Request::Private>(camera);
> > +	return Request::create(std::move(d), cookie);
> > +}
> > +
> >   /**
> >    * \fn PipelineHandler::queueRequestDevice()
> >    * \brief Queue a request to the device
> > diff --git a/src/libcamera/request.cpp b/src/libcamera/request.cpp
> > index 949c556fa437..d1051ad3d25e 100644
> > --- a/src/libcamera/request.cpp
> > +++ b/src/libcamera/request.cpp
> > @@ -336,7 +336,7 @@ void Request::Private::timeout()
> >   /**
> >    * \brief Create a capture request for a camera
> > - * \param[in] camera The camera that creates the request
> > + * \param[in] d The request private data
> >    * \param[in] cookie Opaque cookie for application use
> >    *
> >    * The \a cookie is stored in the request and is accessible through the
> > @@ -344,12 +344,17 @@ void Request::Private::timeout()
> >    * the request to an external resource in the request completion handler, and is
> >    * completely opaque to libcamera.
> >    */
> > -Request::Request(Camera *camera, uint64_t cookie)
> > -	: Extensible(std::make_unique<Private>(camera)),
> > -	  cookie_(cookie), status_(RequestPending)
> > +std::unique_ptr<Request> Request::create(std::unique_ptr<Private> d,
> > +					 uint64_t cookie)
> > +{
> > +	return std::make_unique<Request>(std::move(d), cookie);
> > +}
> > +
>
>
> I'm sure this is just me not understanding c++ properly; but what's the
> reason for this function? Why not just use the class constructor?
>

It's an helper, to easily create a unique_ptr<> from a Request. I
think pipeline handlers can live without it


 std::unique_ptr<Request> PipelineHandlerRkISP1::createRequestDevice(Camera *camera,
                                                                    uint64_t cookie)
 {
-       auto request = std::make_unique<RkISP1Request>(camera);
-       return Request::create(std::move(request), cookie);
+       return std::make_unique<Request>(std::make_unique<RkISP1Request>(camera),
+                                        cookie);
 }

It just feels nicer

Also note that applications won't be able to use this function or neither the
constructor has they don't have access to internal headers so they
can't provide a Request::Private instance.

> > +Request::Request(std::unique_ptr<Request::Private> d, uint64_t cookie)
> > +	: Extensible(std::move(d)), cookie_(cookie), status_(RequestPending)
> >   {
> >   	controls_ = new ControlList(controls::controls,
> > -				    camera->_d()->validator());
> > +				    _d()->camera()->_d()->validator());
> >   	/**
> >   	 * \todo Add a validator for metadata controls.
> > diff --git a/test/camera/statemachine.cpp b/test/camera/statemachine.cpp
> > index 9c2b0c6a7d99..5714061f88b5 100644
> > --- a/test/camera/statemachine.cpp
> > +++ b/test/camera/statemachine.cpp
> > @@ -38,10 +38,6 @@ protected:
> >   		if (camera_->start() != -EACCES)
> >   			return TestFail;
> > -		Request request(camera_.get());
> > -		if (camera_->queueRequest(&request) != -EACCES)
> > -			return TestFail;
> > -
> >   		/* Test operations which should pass. */
> >   		if (camera_->release())
> >   			return TestFail;
> > @@ -68,10 +64,6 @@ protected:
> >   		if (camera_->start() != -EACCES)
> >   			return TestFail;
> > -		Request request(camera_.get());
> > -		if (camera_->queueRequest(&request) != -EACCES)
> > -			return TestFail;
> > -
> >   		/* Test operations which should pass. */
> >   		if (camera_->stop())
> >   			return TestFail;
> > @@ -95,10 +87,6 @@ protected:
> >   		if (camera_->acquire() != -EBUSY)
> >   			return TestFail;
> > -		Request request1(camera_.get());
> > -		if (camera_->queueRequest(&request1) != -EACCES)
> > -			return TestFail;
> > -
> >   		/* Test operations which should pass. */
> >   		std::unique_ptr<Request> request2 = camera_->createRequest();
> >   		if (!request2)


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