libcamera: camera: Take span of StreamRole instead of vector

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>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[Kieran: Apply checkstyle fixups]
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

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;
    }

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 = {});
+
+	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);

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,

src/libcamera/camera.cpp

@@ -937,7 +937,7 @@ 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();
 
@@ -970,6 +970,12 @@ std::unique_ptr<CameraConfiguration> Camera::generateConfiguration(const StreamR
 	return config;
 }
 
+/**
+ * \fn std::unique_ptr<CameraConfiguration> \
+ *     Camera::generateConfiguration(std::initializer_list<StreamRole> roles)
+ * \overload
+ */
+
 /**
  * \brief Configure the camera prior to capture
  * \param[in] config The camera configurations to setup

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 =

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 =

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,
@@ -611,7 +611,7 @@ PipelineHandlerRkISP1::PipelineHandlerRkISP1(CameraManager *manager)
 
 std::unique_ptr<CameraConfiguration>
 PipelineHandlerRkISP1::generateConfiguration(Camera *camera,
-	const StreamRoles &roles)
+					     Span<const StreamRole> roles)
 {
 	RkISP1CameraData *data = cameraData(camera);
 

src/libcamera/pipeline/rpi/common/pipeline_base.cpp

@@ -381,7 +381,7 @@ V4L2DeviceFormat PipelineHandlerBase::toV4L2DeviceFormat(const V4L2VideoDevice *
 }
 
 std::unique_ptr<CameraConfiguration>
-PipelineHandlerBase::generateConfiguration(Camera *camera, const StreamRoles &roles)
+PipelineHandlerBase::generateConfiguration(Camera *camera, Span<const StreamRole> roles)
 {
 	CameraData *data = cameraData(camera);
 	std::unique_ptr<CameraConfiguration> config =

src/libcamera/pipeline/rpi/common/pipeline_base.h

@@ -214,7 +214,7 @@ public:
 						   BayerFormat::Packing packingReq);
 
 	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, libcamera::Stream *stream,

src/libcamera/pipeline/simple/simple.cpp

@@ -316,7 +316,7 @@ 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,
@@ -1044,7 +1044,7 @@ 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 =

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 =

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 =

src/py/libcamera/py_main.cpp

@@ -208,7 +208,10 @@ 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 &self, CameraConfiguration *config) {
 			int ret = self.configure(config);
 			if (ret)