libcamera: framebuffer: Replace vector with span in constructor

The FrameBuffer constructor takes a list of planes as an std::vector.
The caller may stores the planes in a different type of container,
resulting in the needless allocation of a temporary vector. Replace it
with a span.

Suggested-by: Daniel Rákos <daniel.rakos@rastergrid.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>

include/libcamera/framebuffer.h

@@ -58,11 +58,11 @@ public:
 		unsigned int length;
 	};
 
-	FrameBuffer(const std::vector<Plane> &planes, unsigned int cookie = 0);
+	FrameBuffer(Span<const Plane> planes, unsigned int cookie = 0);
 	FrameBuffer(std::unique_ptr<Private> d);
 	virtual ~FrameBuffer() {}
 
-	const std::vector<Plane> &planes() const;
+	Span<const Plane> planes() const;
 	Request *request() const;
 	const FrameMetadata &metadata() const;
 

include/libcamera/internal/framebuffer.h

@@ -12,6 +12,7 @@
 #include <utility>
 
 #include <libcamera/base/class.h>
+#include <libcamera/base/span.h>
 
 #include <libcamera/fence.h>
 #include <libcamera/framebuffer.h>
@@ -23,7 +24,7 @@ class FrameBuffer::Private : public Extensible::Private
 	LIBCAMERA_DECLARE_PUBLIC(FrameBuffer)
 
 public:
-	Private(const std::vector<Plane> &planes, uint64_t cookie = 0);
+	Private(Span<const Plane> planes, uint64_t cookie = 0);
 	virtual ~Private();
 
 	void setRequest(Request *request) { request_ = request; }

src/android/mm/cros_frame_buffer_allocator.cpp

@@ -29,7 +29,7 @@ class CrosFrameBufferData : public FrameBuffer::Private
 
 public:
 	CrosFrameBufferData(cros::ScopedBufferHandle scopedHandle,
-			    const std::vector<FrameBuffer::Plane> &planes)
+			    Span<const FrameBuffer::Plane> planes)
 		: FrameBuffer::Private(planes), scopedHandle_(std::move(scopedHandle))
 	{
 	}

src/android/mm/generic_frame_buffer_allocator.cpp

@@ -35,7 +35,7 @@ class GenericFrameBufferData : public FrameBuffer::Private
 public:
 	GenericFrameBufferData(struct alloc_device_t *allocDevice,
 			       buffer_handle_t handle,
-			       const std::vector<FrameBuffer::Plane> &planes)
+			       Span<const FrameBuffer::Plane> planes)
 		: FrameBuffer::Private(planes), allocDevice_(allocDevice),
 		  handle_(handle)
 	{

src/libcamera/framebuffer.cpp

@@ -130,9 +130,9 @@ LOG_DEFINE_CATEGORY(Buffer)
  * \param[in] planes The frame memory planes
  * \param[in] cookie Cookie
  */
-FrameBuffer::Private::Private(const std::vector<Plane> &planes, uint64_t cookie)
-	: planes_(planes), cookie_(cookie), request_(nullptr),
-	  isContiguous_(true)
+FrameBuffer::Private::Private(Span<const Plane> planes, uint64_t cookie)
+	: planes_(planes.begin(), planes.end()), cookie_(cookie),
+	  request_(nullptr), isContiguous_(true)
 {
 	metadata_.planes_.resize(planes_.size());
 }
@@ -315,7 +315,7 @@ ino_t fileDescriptorInode(const SharedFD &fd)
  * \param[in] planes The frame memory planes
  * \param[in] cookie Cookie
  */
-FrameBuffer::FrameBuffer(const std::vector<Plane> &planes, unsigned int cookie)
+FrameBuffer::FrameBuffer(Span<const Plane> planes, unsigned int cookie)
 	: FrameBuffer(std::make_unique<Private>(planes, cookie))
 {
 }
@@ -365,7 +365,7 @@ FrameBuffer::FrameBuffer(std::unique_ptr<Private> d)
  * \brief Retrieve the static plane descriptors
  * \return Array of plane descriptors
  */
-const std::vector<FrameBuffer::Plane> &FrameBuffer::planes() const
+Span<const FrameBuffer::Plane> FrameBuffer::planes() const
 {
 	return _d()->planes_;
 }

src/libcamera/pipeline/ipu3/ipu3.cpp

@@ -680,8 +680,12 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera)
 
 	auto pushBuffers = [&](const std::vector<std::unique_ptr<FrameBuffer>> &buffers) {
 		for (const std::unique_ptr<FrameBuffer> &buffer : buffers) {
+			Span<const FrameBuffer::Plane> planes = buffer->planes();
+
 			buffer->setCookie(ipaBufferId++);
-			ipaBuffers_.emplace_back(buffer->cookie(), buffer->planes());
+			ipaBuffers_.emplace_back(buffer->cookie(),
+						 std::vector<FrameBuffer::Plane>{ planes.begin(),
+										  planes.end() });
 		}
 	};
 

src/libcamera/pipeline/mali-c55/mali-c55.cpp

@@ -1137,8 +1137,12 @@ int PipelineHandlerMaliC55::allocateBuffers(Camera *camera)
 			       std::queue<FrameBuffer *> &queue,
 			       std::vector<IPABuffer> &ipaBuffers) {
 		for (const std::unique_ptr<FrameBuffer> &buffer : buffers) {
+			Span<const FrameBuffer::Plane> planes = buffer->planes();
+
 			buffer->setCookie(ipaBufferId++);
-			ipaBuffers.emplace_back(buffer->cookie(), buffer->planes());
+			ipaBuffers.emplace_back(buffer->cookie(),
+						std::vector<FrameBuffer::Plane>{ planes.begin(),
+										 planes.end() });
 			queue.push(buffer.get());
 		}
 	};

src/libcamera/pipeline/rkisp1/rkisp1.cpp

@@ -1031,9 +1031,12 @@ int PipelineHandlerRkISP1::allocateBuffers(Camera *camera)
 	auto pushBuffers = [&](const std::vector<std::unique_ptr<FrameBuffer>> &buffers,
 			       std::queue<FrameBuffer *> &queue) {
 		for (const std::unique_ptr<FrameBuffer> &buffer : buffers) {
+			Span<const FrameBuffer::Plane> planes = buffer->planes();
+
 			buffer->setCookie(ipaBufferId++);
 			data->ipaBuffers_.emplace_back(buffer->cookie(),
-						       buffer->planes());
+						       std::vector<FrameBuffer::Plane>{ planes.begin(),
+											planes.end() });
 			queue.push(buffer.get());
 		}
 	};

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

@@ -883,8 +883,10 @@ void PipelineHandlerBase::mapBuffers(Camera *camera, const BufferMap &buffers, u
 	 * handler and the IPA.
 	 */
 	for (auto const &[id, buffer] : buffers) {
-		bufferIds.push_back(IPABuffer(mask | id,
-					      buffer.buffer->planes()));
+		Span<const FrameBuffer::Plane> planes = buffer.buffer->planes();
+
+		bufferIds.emplace_back(mask | id,
+				       std::vector<FrameBuffer::Plane>{ planes.begin(), planes.end() });
 		data->bufferIds_.insert(mask | id);
 	}
 

src/libcamera/pipeline/vimc/vimc.cpp

@@ -363,8 +363,11 @@ int PipelineHandlerVimc::start(Camera *camera, [[maybe_unused]] const ControlLis
 	/* Map the mock IPA buffers to VIMC IPA to exercise IPC code paths. */
 	std::vector<IPABuffer> ipaBuffers;
 	for (auto [i, buffer] : utils::enumerate(data->mockIPABufs_)) {
+		Span<const FrameBuffer::Plane> planes = buffer->planes();
+
 		buffer->setCookie(i + 1);
-		ipaBuffers.emplace_back(buffer->cookie(), buffer->planes());
+		ipaBuffers.emplace_back(buffer->cookie(),
+					std::vector<FrameBuffer::Plane>{ planes.begin(), planes.end() });
 	}
 	data->ipa_->mapBuffers(ipaBuffers);
 

src/libcamera/pipeline/virtual/virtual.cpp

@@ -315,7 +315,8 @@ int PipelineHandlerVirtual::queueRequestDevice([[maybe_unused]] Camera *camera,
 				fmd.sequence = streamConfig.seq++;
 				fmd.timestamp = timestamp;
 
-				for (const auto [i, p] : utils::enumerate(buffer->planes()))
+				Span<const FrameBuffer::Plane> planes = buffer->planes();
+				for (const auto [i, p] : utils::enumerate(planes))
 					fmd.planes()[i].bytesused = p.length;
 
 				found = true;

src/libcamera/v4l2_videodevice.cpp

@@ -288,7 +288,7 @@ V4L2BufferCache::Entry::Entry(bool free, uint64_t lastUsed, const FrameBuffer &b
 
 bool V4L2BufferCache::Entry::operator==(const FrameBuffer &buffer) const
 {
-	const std::vector<FrameBuffer::Plane> &planes = buffer.planes();
+	Span<const FrameBuffer::Plane> planes = buffer.planes();
 
 	if (planes_.size() != planes.size())
 		return false;
@@ -1676,7 +1676,7 @@ int V4L2VideoDevice::queueBuffer(FrameBuffer *buffer)
 	buf.field = V4L2_FIELD_NONE;
 
 	bool multiPlanar = V4L2_TYPE_IS_MULTIPLANAR(buf.type);
-	const std::vector<FrameBuffer::Plane> &planes = buffer->planes();
+	Span<const FrameBuffer::Plane> planes = buffer->planes();
 	const unsigned int numV4l2Planes = format_.planesCount;
 
 	/*
@@ -1909,7 +1909,7 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer()
 	}
 	metadata.sequence -= firstFrame_.value();
 
-	const std::vector<FrameBuffer::Plane> &framebufferPlanes = buffer->planes();
+	Span<const FrameBuffer::Plane> framebufferPlanes = buffer->planes();
 	unsigned int numV4l2Planes = multiPlanar ? buf.length : 1;
 
 	if (numV4l2Planes != framebufferPlanes.size()) {