[libcamera-devel,RFC,v2,1/2] libcamera: camera: Take span of StreamRole instead of vector
diff mbox series

Message ID 20230503124725.200550-1-pobrn@protonmail.com
State Superseded
Headers show
Series
  • [libcamera-devel,RFC,v2,1/2] libcamera: camera: Take span of StreamRole instead of vector
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Commit Message

Barnabás Pőcze May 3, 2023, 12:47 p.m. UTC 
Change the parameter type of `generateConfiguration()` from
`const std::vector&` to `libcamera::Span`. A span is almost
always preferable to a const vector ref because it does not
force dynamic allocation when none are needed, and it allows
any contiguous container to be used.

A new overload is added that accepts an initializer list so that

  cam->generateConfiguration({ ... })

keeps working.

There is no API break since a span can be constructed from a vector
and the initializer list overload takes care of the initializer lists,
but this change causes an ABI break.

Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
---
 Documentation/guides/pipeline-handler.rst          |  4 ++--
 include/libcamera/camera.h                         | 12 +++++++++++-
 include/libcamera/internal/pipeline_handler.h      |  2 +-
 src/libcamera/camera.cpp                           |  2 +-
 src/libcamera/pipeline/imx8-isi/imx8-isi.cpp       |  4 ++--
 src/libcamera/pipeline/ipu3/ipu3.cpp               |  4 ++--
 src/libcamera/pipeline/raspberrypi/raspberrypi.cpp |  4 ++--
 src/libcamera/pipeline/rkisp1/rkisp1.cpp           |  4 ++--
 src/libcamera/pipeline/simple/simple.cpp           |  4 ++--
 src/libcamera/pipeline/uvcvideo/uvcvideo.cpp       |  4 ++--
 src/libcamera/pipeline/vimc/vimc.cpp               |  4 ++--
 src/py/libcamera/py_main.cpp                       |  5 ++++-
 12 files changed, 33 insertions(+), 20 deletions(-)

--
2.40.1

Comments

Laurent Pinchart May 9, 2023, 7:13 a.m. UTC | #1 
Hi Barnabás,

Thank you for the patch.

On Wed, May 03, 2023 at 12:47:28PM +0000, Barnabás Pőcze via libcamera-devel wrote:
> Change the parameter type of `generateConfiguration()` from
> `const std::vector&` to `libcamera::Span`. A span is almost
> always preferable to a const vector ref because it does not
> force dynamic allocation when none are needed, and it allows
> any contiguous container to be used.

There's no need to wrap at 60 columns, you can use the normal 72 columns
wrapping for commit messages.

> A new overload is added that accepts an initializer list so that
> 
>   cam->generateConfiguration({ ... })
> 
> keeps working.
> 
> There is no API break since a span can be constructed from a vector
> and the initializer list overload takes care of the initializer lists,
> but this change causes an ABI break.
> 
> Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
> ---
>  Documentation/guides/pipeline-handler.rst          |  4 ++--
>  include/libcamera/camera.h                         | 12 +++++++++++-
>  include/libcamera/internal/pipeline_handler.h      |  2 +-
>  src/libcamera/camera.cpp                           |  2 +-
>  src/libcamera/pipeline/imx8-isi/imx8-isi.cpp       |  4 ++--
>  src/libcamera/pipeline/ipu3/ipu3.cpp               |  4 ++--
>  src/libcamera/pipeline/raspberrypi/raspberrypi.cpp |  4 ++--
>  src/libcamera/pipeline/rkisp1/rkisp1.cpp           |  4 ++--
>  src/libcamera/pipeline/simple/simple.cpp           |  4 ++--
>  src/libcamera/pipeline/uvcvideo/uvcvideo.cpp       |  4 ++--
>  src/libcamera/pipeline/vimc/vimc.cpp               |  4 ++--
>  src/py/libcamera/py_main.cpp                       |  5 ++++-
>  12 files changed, 33 insertions(+), 20 deletions(-)
> 
> diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
> index 1acd1812..e08bb72f 100644
> --- a/Documentation/guides/pipeline-handler.rst
> +++ b/Documentation/guides/pipeline-handler.rst
> @@ -203,7 +203,7 @@ implementations for the overridden class members.
>            PipelineHandlerVivid(CameraManager *manager);
> 
>            CameraConfiguration *generateConfiguration(Camera *camera,
> -          const StreamRoles &roles) override;
> +          Span<const StreamRole> roles) override;
>            int configure(Camera *camera, CameraConfiguration *config) override;
> 
>            int exportFrameBuffers(Camera *camera, Stream *stream,
> @@ -223,7 +223,7 @@ implementations for the overridden class members.
>     }
> 
>     CameraConfiguration *PipelineHandlerVivid::generateConfiguration(Camera *camera,
> -                                                                    const StreamRoles &roles)
> +                                                                    Span<const StreamRole> roles)
>     {
>            return nullptr;
>     }
> diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
> index 5bb06584..425fe51b 100644
> --- a/include/libcamera/camera.h
> +++ b/include/libcamera/camera.h
> @@ -7,6 +7,7 @@
> 
>  #pragma once
> 
> +#include <initializer_list>
>  #include <memory>
>  #include <set>
>  #include <stdint.h>
> @@ -105,7 +106,16 @@ public:
>  	const ControlList &properties() const;
> 
>  	const std::set<Stream *> &streams() const;
> -	std::unique_ptr<CameraConfiguration> generateConfiguration(const StreamRoles &roles = {});
> +	std::unique_ptr<CameraConfiguration> generateConfiguration(Span<const StreamRole> roles = {});
> +
> +	/**
> +	 * \overload
> +	 */

Documentation belongs to the .cpp file.

> +	std::unique_ptr<CameraConfiguration> generateConfiguration(std::initializer_list<StreamRole> roles)

I'd wrap this to

	std::unique_ptr<CameraConfiguration>
	generateConfiguration(std::initializer_list<StreamRole> roles)

as it's getting long. Maybe above as well.

> +	{
> +		return generateConfiguration(Span(roles.begin(), roles.end()));
> +	}
> +
>  	int configure(CameraConfiguration *config);
> 
>  	std::unique_ptr<Request> createRequest(uint64_t cookie = 0);
> diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h
> index 4c4dfe62..aaeb3a9e 100644
> --- a/include/libcamera/internal/pipeline_handler.h
> +++ b/include/libcamera/internal/pipeline_handler.h
> @@ -49,7 +49,7 @@ public:
>  	void release(Camera *camera);
> 
>  	virtual std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
> -		const StreamRoles &roles) = 0;
> +		Span<const StreamRole> roles) = 0;
>  	virtual int configure(Camera *camera, CameraConfiguration *config) = 0;
> 
>  	virtual int exportFrameBuffers(Camera *camera, Stream *stream,
> diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
> index 99683e49..f53fcdfd 100644
> --- a/src/libcamera/camera.cpp
> +++ b/src/libcamera/camera.cpp
> @@ -938,7 +938,7 @@ const std::set<Stream *> &Camera::streams() const
>   * \return A CameraConfiguration if the requested roles can be satisfied, or a
>   * null pointer otherwise.
>   */
> -std::unique_ptr<CameraConfiguration> Camera::generateConfiguration(const StreamRoles &roles)
> +std::unique_ptr<CameraConfiguration> Camera::generateConfiguration(Span<const StreamRole> roles)
>  {
>  	Private *const d = _d();
> 
> diff --git a/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp b/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
> index 449d9012..9bdfff0b 100644
> --- a/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
> +++ b/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
> @@ -104,7 +104,7 @@ public:
>  	bool match(DeviceEnumerator *enumerator) override;
> 
>  	std::unique_ptr<CameraConfiguration>
> -	generateConfiguration(Camera *camera, const StreamRoles &roles) override;
> +	generateConfiguration(Camera *camera, Span<const StreamRole> roles) override;
>  	int configure(Camera *camera, CameraConfiguration *config) override;
> 
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
> @@ -739,7 +739,7 @@ StreamConfiguration PipelineHandlerISI::generateRawConfiguration(Camera *camera)
> 
>  std::unique_ptr<CameraConfiguration>
>  PipelineHandlerISI::generateConfiguration(Camera *camera,
> -					  const StreamRoles &roles)
> +					  Span<const StreamRole> roles)
>  {
>  	ISICameraData *data = cameraData(camera);
>  	std::unique_ptr<ISICameraConfiguration> config =
> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> index 355cb0cb..ada8c272 100644
> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> @@ -135,7 +135,7 @@ public:
>  	PipelineHandlerIPU3(CameraManager *manager);
> 
>  	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
> -		const StreamRoles &roles) override;
> +		Span<const StreamRole> roles) override;
>  	int configure(Camera *camera, CameraConfiguration *config) override;
> 
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
> @@ -390,7 +390,7 @@ PipelineHandlerIPU3::PipelineHandlerIPU3(CameraManager *manager)
>  }
> 
>  std::unique_ptr<CameraConfiguration>
> -PipelineHandlerIPU3::generateConfiguration(Camera *camera, const StreamRoles &roles)
> +PipelineHandlerIPU3::generateConfiguration(Camera *camera, Span<const StreamRole> roles)
>  {
>  	IPU3CameraData *data = cameraData(camera);
>  	std::unique_ptr<IPU3CameraConfiguration> config =
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index 00600441..6421eda5 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -367,7 +367,7 @@ public:
>  	PipelineHandlerRPi(CameraManager *manager);
> 
>  	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
> -		const StreamRoles &roles) override;
> +		Span<const StreamRole> roles) override;
>  	int configure(Camera *camera, CameraConfiguration *config) override;
> 
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
> @@ -667,7 +667,7 @@ PipelineHandlerRPi::PipelineHandlerRPi(CameraManager *manager)
>  }
> 
>  std::unique_ptr<CameraConfiguration>
> -PipelineHandlerRPi::generateConfiguration(Camera *camera, const StreamRoles &roles)
> +PipelineHandlerRPi::generateConfiguration(Camera *camera, Span<const StreamRole> roles)
>  {
>  	RPiCameraData *data = cameraData(camera);
>  	std::unique_ptr<CameraConfiguration> config =
> diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> index 8a30fe06..1fdfde7b 100644
> --- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> +++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> @@ -148,7 +148,7 @@ public:
>  	PipelineHandlerRkISP1(CameraManager *manager);
> 
>  	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
> -		const StreamRoles &roles) override;
> +		Span<const StreamRole> roles) override;
>  	int configure(Camera *camera, CameraConfiguration *config) override;
> 
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
> @@ -609,7 +609,7 @@ PipelineHandlerRkISP1::PipelineHandlerRkISP1(CameraManager *manager)
> 
>  std::unique_ptr<CameraConfiguration>
>  PipelineHandlerRkISP1::generateConfiguration(Camera *camera,
> -	const StreamRoles &roles)
> +	Span<const StreamRole> roles)
>  {
>  	RkISP1CameraData *data = cameraData(camera);
> 
> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> index e1f8b989..d6e0758e 100644
> --- a/src/libcamera/pipeline/simple/simple.cpp
> +++ b/src/libcamera/pipeline/simple/simple.cpp
> @@ -315,7 +315,7 @@ public:
>  	SimplePipelineHandler(CameraManager *manager);
> 
>  	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
> -		const StreamRoles &roles) override;
> +		Span<const StreamRole> roles) override;
>  	int configure(Camera *camera, CameraConfiguration *config) override;
> 
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
> @@ -1043,7 +1043,7 @@ SimplePipelineHandler::SimplePipelineHandler(CameraManager *manager)
>  }
> 
>  std::unique_ptr<CameraConfiguration>
> -SimplePipelineHandler::generateConfiguration(Camera *camera, const StreamRoles &roles)
> +SimplePipelineHandler::generateConfiguration(Camera *camera, Span<const StreamRole> roles)
>  {
>  	SimpleCameraData *data = cameraData(camera);
>  	std::unique_ptr<CameraConfiguration> config =
> diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> index 277465b7..03935876 100644
> --- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> +++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> @@ -75,7 +75,7 @@ public:
>  	PipelineHandlerUVC(CameraManager *manager);
> 
>  	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
> -		const StreamRoles &roles) override;
> +		Span<const StreamRole> roles) override;
>  	int configure(Camera *camera, CameraConfiguration *config) override;
> 
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
> @@ -180,7 +180,7 @@ PipelineHandlerUVC::PipelineHandlerUVC(CameraManager *manager)
> 
>  std::unique_ptr<CameraConfiguration>
>  PipelineHandlerUVC::generateConfiguration(Camera *camera,
> -	const StreamRoles &roles)
> +	Span<const StreamRole> roles)
>  {
>  	UVCCameraData *data = cameraData(camera);
>  	std::unique_ptr<CameraConfiguration> config =
> diff --git a/src/libcamera/pipeline/vimc/vimc.cpp b/src/libcamera/pipeline/vimc/vimc.cpp
> index 204f5ad7..49ee949f 100644
> --- a/src/libcamera/pipeline/vimc/vimc.cpp
> +++ b/src/libcamera/pipeline/vimc/vimc.cpp
> @@ -85,7 +85,7 @@ public:
>  	PipelineHandlerVimc(CameraManager *manager);
> 
>  	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
> -		const StreamRoles &roles) override;
> +		Span<const StreamRole> roles) override;
>  	int configure(Camera *camera, CameraConfiguration *config) override;
> 
>  	int exportFrameBuffers(Camera *camera, Stream *stream,
> @@ -191,7 +191,7 @@ PipelineHandlerVimc::PipelineHandlerVimc(CameraManager *manager)
> 
>  std::unique_ptr<CameraConfiguration>
>  PipelineHandlerVimc::generateConfiguration(Camera *camera,
> -	const StreamRoles &roles)
> +	Span<const StreamRole> roles)
>  {
>  	VimcCameraData *data = cameraData(camera);
>  	std::unique_ptr<CameraConfiguration> config =
> diff --git a/src/py/libcamera/py_main.cpp b/src/py/libcamera/py_main.cpp
> index d14e18e2..3f04871f 100644
> --- a/src/py/libcamera/py_main.cpp
> +++ b/src/py/libcamera/py_main.cpp
> @@ -156,7 +156,10 @@ PYBIND11_MODULE(_libcamera, m)
>  		})
> 
>  		/* Keep the camera alive, as StreamConfiguration contains a Stream* */
> -		.def("generate_configuration", &Camera::generateConfiguration, py::keep_alive<0, 1>())
> +		.def("generate_configuration", [](Camera &self, const std::vector<StreamRole> &roles) {
> +			return self.generateConfiguration(roles);
> +		}, py::keep_alive<0, 1>())
> +
>  		.def("configure", &Camera::configure)
> 
>  		.def("create_request", &Camera::createRequest, py::arg("cookie") = 0)
Barnabás Pőcze May 9, 2023, 10:15 p.m. UTC | #2 
Hi


2023. május 9., kedd 9:13 keltezéssel, Laurent Pinchart <laurent.pinchart@ideasonboard.com> írta:

> Hi Barnabás,
>
> Thank you for the patch.
>
> On Wed, May 03, 2023 at 12:47:28PM +0000, Barnabás Pőcze via libcamera-devel wrote:
> > Change the parameter type of `generateConfiguration()` from
> > `const std::vector&` to `libcamera::Span`. A span is almost
> > always preferable to a const vector ref because it does not
> > force dynamic allocation when none are needed, and it allows
> > any contiguous container to be used.
>
> There's no need to wrap at 60 columns, you can use the normal 72 columns
> wrapping for commit messages.

I did not want to break "const std::vector&" and not breaking before
that makes the line ~80 chars long. I will send a new version with that.


>
> > A new overload is added that accepts an initializer list so that
> >
> >   cam->generateConfiguration({ ... })
> >
> > keeps working.
> >
> > There is no API break since a span can be constructed from a vector
> > and the initializer list overload takes care of the initializer lists,
> > but this change causes an ABI break.
> >
> > Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
> > ---
> >  Documentation/guides/pipeline-handler.rst          |  4 ++--
> >  include/libcamera/camera.h                         | 12 +++++++++++-
> >  include/libcamera/internal/pipeline_handler.h      |  2 +-
> >  src/libcamera/camera.cpp                           |  2 +-
> >  src/libcamera/pipeline/imx8-isi/imx8-isi.cpp       |  4 ++--
> >  src/libcamera/pipeline/ipu3/ipu3.cpp               |  4 ++--
> >  src/libcamera/pipeline/raspberrypi/raspberrypi.cpp |  4 ++--
> >  src/libcamera/pipeline/rkisp1/rkisp1.cpp           |  4 ++--
> >  src/libcamera/pipeline/simple/simple.cpp           |  4 ++--
> >  src/libcamera/pipeline/uvcvideo/uvcvideo.cpp       |  4 ++--
> >  src/libcamera/pipeline/vimc/vimc.cpp               |  4 ++--
> >  src/py/libcamera/py_main.cpp                       |  5 ++++-
> >  12 files changed, 33 insertions(+), 20 deletions(-)
> >
> > diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
> > index 1acd1812..e08bb72f 100644
> > --- a/Documentation/guides/pipeline-handler.rst
> > +++ b/Documentation/guides/pipeline-handler.rst
> > @@ -203,7 +203,7 @@ implementations for the overridden class members.
> >            PipelineHandlerVivid(CameraManager *manager);
> >
> >            CameraConfiguration *generateConfiguration(Camera *camera,
> > -          const StreamRoles &roles) override;
> > +          Span<const StreamRole> roles) override;
> >            int configure(Camera *camera, CameraConfiguration *config) override;
> >
> >            int exportFrameBuffers(Camera *camera, Stream *stream,
> > @@ -223,7 +223,7 @@ implementations for the overridden class members.
> >     }
> >
> >     CameraConfiguration *PipelineHandlerVivid::generateConfiguration(Camera *camera,
> > -                                                                    const StreamRoles &roles)
> > +                                                                    Span<const StreamRole> roles)
> >     {
> >            return nullptr;
> >     }
> > diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
> > index 5bb06584..425fe51b 100644
> > --- a/include/libcamera/camera.h
> > +++ b/include/libcamera/camera.h
> > @@ -7,6 +7,7 @@
> >
> >  #pragma once
> >
> > +#include <initializer_list>
> >  #include <memory>
> >  #include <set>
> >  #include <stdint.h>
> > @@ -105,7 +106,16 @@ public:
> >  	const ControlList &properties() const;
> >
> >  	const std::set<Stream *> &streams() const;
> > -	std::unique_ptr<CameraConfiguration> generateConfiguration(const StreamRoles &roles = {});
> > +	std::unique_ptr<CameraConfiguration> generateConfiguration(Span<const StreamRole> roles = {});
> > +
> > +	/**
> > +	 * \overload
> > +	 */
>
> Documentation belongs to the .cpp file.

ACK


>
> > +	std::unique_ptr<CameraConfiguration> generateConfiguration(std::initializer_list<StreamRole> roles)
>
> I'd wrap this to
>
> 	std::unique_ptr<CameraConfiguration>
> 	generateConfiguration(std::initializer_list<StreamRole> roles)
>
> as it's getting long. Maybe above as well.


ACK

>
> > +	{
> > +		return generateConfiguration(Span(roles.begin(), roles.end()));
> > +	}
> > +
> >  	int configure(CameraConfiguration *config);
> >
> >  	std::unique_ptr<Request> createRequest(uint64_t cookie = 0);
> [...]


Regards,
Barnabás Pőcze

Patch
diff mbox series 

diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
index 1acd1812..e08bb72f 100644
--- a/Documentation/guides/pipeline-handler.rst
+++ b/Documentation/guides/pipeline-handler.rst
@@ -203,7 +203,7 @@  implementations for the overridden class members.
           PipelineHandlerVivid(CameraManager *manager);

           CameraConfiguration *generateConfiguration(Camera *camera,
-          const StreamRoles &roles) override;
+          Span<const StreamRole> roles) override;
           int configure(Camera *camera, CameraConfiguration *config) override;

           int exportFrameBuffers(Camera *camera, Stream *stream,
@@ -223,7 +223,7 @@  implementations for the overridden class members.
    }

    CameraConfiguration *PipelineHandlerVivid::generateConfiguration(Camera *camera,
-                                                                    const StreamRoles &roles)
+                                                                    Span<const StreamRole> roles)
    {
           return nullptr;
    }
diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index 5bb06584..425fe51b 100644
--- a/include/libcamera/camera.h
+++ b/include/libcamera/camera.h
@@ -7,6 +7,7 @@ 

 #pragma once

+#include <initializer_list>
 #include <memory>
 #include <set>
 #include <stdint.h>
@@ -105,7 +106,16 @@  public:
 	const ControlList &properties() const;

 	const std::set<Stream *> &streams() const;
-	std::unique_ptr<CameraConfiguration> generateConfiguration(const StreamRoles &roles = {});
+	std::unique_ptr<CameraConfiguration> generateConfiguration(Span<const StreamRole> roles = {});
+
+	/**
+	 * \overload
+	 */
+	std::unique_ptr<CameraConfiguration> generateConfiguration(std::initializer_list<StreamRole> roles)
+	{
+		return generateConfiguration(Span(roles.begin(), roles.end()));
+	}
+
 	int configure(CameraConfiguration *config);

 	std::unique_ptr<Request> createRequest(uint64_t cookie = 0);
diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h
index 4c4dfe62..aaeb3a9e 100644
--- a/include/libcamera/internal/pipeline_handler.h
+++ b/include/libcamera/internal/pipeline_handler.h
@@ -49,7 +49,7 @@  public:
 	void release(Camera *camera);

 	virtual std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
-		const StreamRoles &roles) = 0;
+		Span<const StreamRole> roles) = 0;
 	virtual int configure(Camera *camera, CameraConfiguration *config) = 0;

 	virtual int exportFrameBuffers(Camera *camera, Stream *stream,
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index 99683e49..f53fcdfd 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -938,7 +938,7 @@  const std::set<Stream *> &Camera::streams() const
  * \return A CameraConfiguration if the requested roles can be satisfied, or a
  * null pointer otherwise.
  */
-std::unique_ptr<CameraConfiguration> Camera::generateConfiguration(const StreamRoles &roles)
+std::unique_ptr<CameraConfiguration> Camera::generateConfiguration(Span<const StreamRole> roles)
 {
 	Private *const d = _d();

diff --git a/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp b/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
index 449d9012..9bdfff0b 100644
--- a/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
+++ b/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
@@ -104,7 +104,7 @@  public:
 	bool match(DeviceEnumerator *enumerator) override;

 	std::unique_ptr<CameraConfiguration>
-	generateConfiguration(Camera *camera, const StreamRoles &roles) override;
+	generateConfiguration(Camera *camera, Span<const StreamRole> roles) override;
 	int configure(Camera *camera, CameraConfiguration *config) override;

 	int exportFrameBuffers(Camera *camera, Stream *stream,
@@ -739,7 +739,7 @@  StreamConfiguration PipelineHandlerISI::generateRawConfiguration(Camera *camera)

 std::unique_ptr<CameraConfiguration>
 PipelineHandlerISI::generateConfiguration(Camera *camera,
-					  const StreamRoles &roles)
+					  Span<const StreamRole> roles)
 {
 	ISICameraData *data = cameraData(camera);
 	std::unique_ptr<ISICameraConfiguration> config =
diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index 355cb0cb..ada8c272 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -135,7 +135,7 @@  public:
 	PipelineHandlerIPU3(CameraManager *manager);

 	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
-		const StreamRoles &roles) override;
+		Span<const StreamRole> roles) override;
 	int configure(Camera *camera, CameraConfiguration *config) override;

 	int exportFrameBuffers(Camera *camera, Stream *stream,
@@ -390,7 +390,7 @@  PipelineHandlerIPU3::PipelineHandlerIPU3(CameraManager *manager)
 }

 std::unique_ptr<CameraConfiguration>
-PipelineHandlerIPU3::generateConfiguration(Camera *camera, const StreamRoles &roles)
+PipelineHandlerIPU3::generateConfiguration(Camera *camera, Span<const StreamRole> roles)
 {
 	IPU3CameraData *data = cameraData(camera);
 	std::unique_ptr<IPU3CameraConfiguration> config =
diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 00600441..6421eda5 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -367,7 +367,7 @@  public:
 	PipelineHandlerRPi(CameraManager *manager);

 	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
-		const StreamRoles &roles) override;
+		Span<const StreamRole> roles) override;
 	int configure(Camera *camera, CameraConfiguration *config) override;

 	int exportFrameBuffers(Camera *camera, Stream *stream,
@@ -667,7 +667,7 @@  PipelineHandlerRPi::PipelineHandlerRPi(CameraManager *manager)
 }

 std::unique_ptr<CameraConfiguration>
-PipelineHandlerRPi::generateConfiguration(Camera *camera, const StreamRoles &roles)
+PipelineHandlerRPi::generateConfiguration(Camera *camera, Span<const StreamRole> roles)
 {
 	RPiCameraData *data = cameraData(camera);
 	std::unique_ptr<CameraConfiguration> config =
diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
index 8a30fe06..1fdfde7b 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
+++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
@@ -148,7 +148,7 @@  public:
 	PipelineHandlerRkISP1(CameraManager *manager);

 	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
-		const StreamRoles &roles) override;
+		Span<const StreamRole> roles) override;
 	int configure(Camera *camera, CameraConfiguration *config) override;

 	int exportFrameBuffers(Camera *camera, Stream *stream,
@@ -609,7 +609,7 @@  PipelineHandlerRkISP1::PipelineHandlerRkISP1(CameraManager *manager)

 std::unique_ptr<CameraConfiguration>
 PipelineHandlerRkISP1::generateConfiguration(Camera *camera,
-	const StreamRoles &roles)
+	Span<const StreamRole> roles)
 {
 	RkISP1CameraData *data = cameraData(camera);

diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
index e1f8b989..d6e0758e 100644
--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
@@ -315,7 +315,7 @@  public:
 	SimplePipelineHandler(CameraManager *manager);

 	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
-		const StreamRoles &roles) override;
+		Span<const StreamRole> roles) override;
 	int configure(Camera *camera, CameraConfiguration *config) override;

 	int exportFrameBuffers(Camera *camera, Stream *stream,
@@ -1043,7 +1043,7 @@  SimplePipelineHandler::SimplePipelineHandler(CameraManager *manager)
 }

 std::unique_ptr<CameraConfiguration>
-SimplePipelineHandler::generateConfiguration(Camera *camera, const StreamRoles &roles)
+SimplePipelineHandler::generateConfiguration(Camera *camera, Span<const StreamRole> roles)
 {
 	SimpleCameraData *data = cameraData(camera);
 	std::unique_ptr<CameraConfiguration> config =
diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
index 277465b7..03935876 100644
--- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
@@ -75,7 +75,7 @@  public:
 	PipelineHandlerUVC(CameraManager *manager);

 	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
-		const StreamRoles &roles) override;
+		Span<const StreamRole> roles) override;
 	int configure(Camera *camera, CameraConfiguration *config) override;

 	int exportFrameBuffers(Camera *camera, Stream *stream,
@@ -180,7 +180,7 @@  PipelineHandlerUVC::PipelineHandlerUVC(CameraManager *manager)

 std::unique_ptr<CameraConfiguration>
 PipelineHandlerUVC::generateConfiguration(Camera *camera,
-	const StreamRoles &roles)
+	Span<const StreamRole> roles)
 {
 	UVCCameraData *data = cameraData(camera);
 	std::unique_ptr<CameraConfiguration> config =
diff --git a/src/libcamera/pipeline/vimc/vimc.cpp b/src/libcamera/pipeline/vimc/vimc.cpp
index 204f5ad7..49ee949f 100644
--- a/src/libcamera/pipeline/vimc/vimc.cpp
+++ b/src/libcamera/pipeline/vimc/vimc.cpp
@@ -85,7 +85,7 @@  public:
 	PipelineHandlerVimc(CameraManager *manager);

 	std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
-		const StreamRoles &roles) override;
+		Span<const StreamRole> roles) override;
 	int configure(Camera *camera, CameraConfiguration *config) override;

 	int exportFrameBuffers(Camera *camera, Stream *stream,
@@ -191,7 +191,7 @@  PipelineHandlerVimc::PipelineHandlerVimc(CameraManager *manager)

 std::unique_ptr<CameraConfiguration>
 PipelineHandlerVimc::generateConfiguration(Camera *camera,
-	const StreamRoles &roles)
+	Span<const StreamRole> roles)
 {
 	VimcCameraData *data = cameraData(camera);
 	std::unique_ptr<CameraConfiguration> config =
diff --git a/src/py/libcamera/py_main.cpp b/src/py/libcamera/py_main.cpp
index d14e18e2..3f04871f 100644
--- a/src/py/libcamera/py_main.cpp
+++ b/src/py/libcamera/py_main.cpp
@@ -156,7 +156,10 @@  PYBIND11_MODULE(_libcamera, m)
 		})

 		/* Keep the camera alive, as StreamConfiguration contains a Stream* */
-		.def("generate_configuration", &Camera::generateConfiguration, py::keep_alive<0, 1>())
+		.def("generate_configuration", [](Camera &self, const std::vector<StreamRole> &roles) {
+			return self.generateConfiguration(roles);
+		}, py::keep_alive<0, 1>())
+
 		.def("configure", &Camera::configure)

 		.def("create_request", &Camera::createRequest, py::arg("cookie") = 0)