libcamera: controls: Use std::optional to handle invalid control values

Previously, ControlList::get<T>() would use default constructed objects to
indicate that a ControlList does not have the requested Control. This has
several disadvantages: 1) It requires types to be default constructible,
2) it does not differentiate between a default constructed object and an
object that happens to have the same state as a default constructed object.

std::optional<T> additionally stores the information if the object is valid
or not, and therefore is more expressive than a default constructed object.

Signed-off-by: Christian Rauch <Rauch.Christian@gmx.de>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/libcamera/controls.h

@@ -8,6 +8,7 @@
 #pragma once
 
 #include <assert.h>
+#include <optional>
 #include <set>
 #include <stdint.h>
 #include <string>
@@ -373,11 +374,11 @@ public:
 	bool contains(unsigned int id) const;
 
 	template<typename T>
-	T get(const Control<T> &ctrl) const
+	std::optional<T> get(const Control<T> &ctrl) const
 	{
 		const ControlValue *val = find(ctrl.id());
 		if (!val)
-			return T{};
+			return std::nullopt;
 
 		return val->get<T>();
 	}

src/android/camera_capabilities.cpp

@@ -1042,7 +1042,7 @@ int CameraCapabilities::initializeStaticMetadata()
 	/* Sensor static metadata. */
 	std::array<int32_t, 2> pixelArraySize;
 	{
-		const Size &size = properties.get(properties::PixelArraySize);
+		const Size &size = properties.get(properties::PixelArraySize).value_or(Size{});
 		pixelArraySize[0] = size.width;
 		pixelArraySize[1] = size.height;
 		staticMetadata_->addEntry(ANDROID_SENSOR_INFO_PIXEL_ARRAY_SIZE,
@@ -1050,10 +1050,10 @@ int CameraCapabilities::initializeStaticMetadata()
 	}
 
 	if (properties.contains(properties::UnitCellSize)) {
-		const Size &cellSize = properties.get<Size>(properties::UnitCellSize);
+		const auto &cellSize = properties.get<Size>(properties::UnitCellSize);
 		std::array<float, 2> physicalSize{
-			cellSize.width * pixelArraySize[0] / 1e6f,
+			cellSize->width * pixelArraySize[0] / 1e6f,
-			cellSize.height * pixelArraySize[1] / 1e6f
+			cellSize->height * pixelArraySize[1] / 1e6f
 		};
 		staticMetadata_->addEntry(ANDROID_SENSOR_INFO_PHYSICAL_SIZE,
 					  physicalSize);
@@ -1061,7 +1061,7 @@ int CameraCapabilities::initializeStaticMetadata()
 
 	{
 		const Span<const Rectangle> &rects =
-			properties.get(properties::PixelArrayActiveAreas);
+			properties.get(properties::PixelArrayActiveAreas).value_or(Span<const Rectangle>{});
 		std::vector<int32_t> data{
 			static_cast<int32_t>(rects[0].x),
 			static_cast<int32_t>(rects[0].y),
@@ -1080,7 +1080,7 @@ int CameraCapabilities::initializeStaticMetadata()
 
 	/* Report the color filter arrangement if the camera reports it. */
 	if (properties.contains(properties::draft::ColorFilterArrangement)) {
-		uint8_t filterArr = properties.get(properties::draft::ColorFilterArrangement);
+		uint8_t filterArr = *properties.get(properties::draft::ColorFilterArrangement);
 		staticMetadata_->addEntry(ANDROID_SENSOR_INFO_COLOR_FILTER_ARRANGEMENT,
 					  filterArr);
 	}

src/android/camera_device.cpp

@@ -306,7 +306,7 @@ int CameraDevice::initialize(const CameraConfigData *cameraConfigData)
 	const ControlList &properties = camera_->properties();
 
 	if (properties.contains(properties::Location)) {
-		int32_t location = properties.get(properties::Location);
+		int32_t location = *properties.get(properties::Location);
 		switch (location) {
 		case properties::CameraLocationFront:
 			facing_ = CAMERA_FACING_FRONT;
@@ -356,7 +356,7 @@ int CameraDevice::initialize(const CameraConfigData *cameraConfigData)
 	 * metadata.
 	 */
 	if (properties.contains(properties::Rotation)) {
-		int rotation = properties.get(properties::Rotation);
+		int rotation = *properties.get(properties::Rotation);
 		orientation_ = (360 - rotation) % 360;
 		if (cameraConfigData && cameraConfigData->rotation != -1 &&
 		    orientation_ != cameraConfigData->rotation) {
@@ -1181,7 +1181,8 @@ void CameraDevice::requestComplete(Request *request)
 	 * as soon as possible, earlier than request completion time.
 	 */
 	uint64_t sensorTimestamp = static_cast<uint64_t>(request->metadata()
-							 .get(controls::SensorTimestamp));
+								 .get(controls::SensorTimestamp)
+								 .value_or(0));
 	notifyShutter(descriptor->frameNumber_, sensorTimestamp);
 
 	LOG(HAL, Debug) << "Request " << request->cookie() << " completed with "
@@ -1560,29 +1561,28 @@ CameraDevice::getResultMetadata(const Camera3RequestDescriptor &descriptor) cons
 				 rolling_shutter_skew);
 
 	/* Add metadata tags reported by libcamera. */
-	const int64_t timestamp = metadata.get(controls::SensorTimestamp);
+	const int64_t timestamp = metadata.get(controls::SensorTimestamp).value_or(0);
 	resultMetadata->addEntry(ANDROID_SENSOR_TIMESTAMP, timestamp);
 
 	if (metadata.contains(controls::draft::PipelineDepth)) {
-		uint8_t pipeline_depth =
+		uint8_t pipeline_depth = *metadata.get<int32_t>(controls::draft::PipelineDepth);
-			metadata.get<int32_t>(controls::draft::PipelineDepth);
 		resultMetadata->addEntry(ANDROID_REQUEST_PIPELINE_DEPTH,
 					 pipeline_depth);
 	}
 
 	if (metadata.contains(controls::ExposureTime)) {
-		int64_t exposure = metadata.get(controls::ExposureTime) * 1000ULL;
+		int64_t exposure = *metadata.get(controls::ExposureTime) * 1000ULL;
 		resultMetadata->addEntry(ANDROID_SENSOR_EXPOSURE_TIME, exposure);
 	}
 
 	if (metadata.contains(controls::FrameDuration)) {
-		int64_t duration = metadata.get(controls::FrameDuration) * 1000;
+		int64_t duration = *metadata.get(controls::FrameDuration) * 1000;
 		resultMetadata->addEntry(ANDROID_SENSOR_FRAME_DURATION,
 					 duration);
 	}
 
 	if (metadata.contains(controls::ScalerCrop)) {
-		Rectangle crop = metadata.get(controls::ScalerCrop);
+		Rectangle crop = *metadata.get(controls::ScalerCrop);
 		int32_t cropRect[] = {
 			crop.x, crop.y, static_cast<int32_t>(crop.width),
 			static_cast<int32_t>(crop.height),
@@ -1591,8 +1591,7 @@ CameraDevice::getResultMetadata(const Camera3RequestDescriptor &descriptor) cons
 	}
 
 	if (metadata.contains(controls::draft::TestPatternMode)) {
-		const int32_t testPatternMode =
+		const int32_t testPatternMode = *metadata.get(controls::draft::TestPatternMode);
-			metadata.get(controls::draft::TestPatternMode);
 		resultMetadata->addEntry(ANDROID_SENSOR_TEST_PATTERN_MODE,
 					 testPatternMode);
 	}

src/android/camera_hal_manager.cpp

@@ -232,7 +232,7 @@ int32_t CameraHalManager::cameraLocation(const Camera *cam)
 	if (!properties.contains(properties::Location))
 		return -1;
 
-	return properties.get(properties::Location);
+	return *properties.get(properties::Location);
 }
 
 CameraDevice *CameraHalManager::cameraDeviceFromHalId(unsigned int id)

src/cam/main.cpp

@@ -301,7 +301,7 @@ std::string CamApp::cameraName(const Camera *camera)
 	 * is only used if the location isn't present or is set to External.
 	 */
 	if (props.contains(properties::Location)) {
-		switch (props.get(properties::Location)) {
+		switch (*props.get(properties::Location)) {
 		case properties::CameraLocationFront:
 			addModel = false;
 			name = "Internal front camera ";
@@ -321,7 +321,7 @@ std::string CamApp::cameraName(const Camera *camera)
 		 * If the camera location is not availble use the camera model
 		 * to build the camera name.
 		 */
-		name = "'" + props.get(properties::Model) + "' ";
+		name = "'" + *props.get(properties::Model) + "' ";
 	}
 
 	name += "(" + camera->id() + ")";

src/gstreamer/gstlibcamerasrc.cpp

@@ -234,7 +234,7 @@ GstLibcameraSrcState::requestCompleted(Request *request)
 	}
 
 	if (GST_ELEMENT_CLOCK(src_)) {
-		int64_t timestamp = request->metadata().get(controls::SensorTimestamp);
+		int64_t timestamp = request->metadata().get(controls::SensorTimestamp).value_or(0);
 
 		GstClockTime gst_base_time = GST_ELEMENT(src_)->base_time;
 		GstClockTime gst_now = gst_clock_get_time(GST_ELEMENT_CLOCK(src_));

src/ipa/raspberrypi/raspberrypi.cpp

@@ -993,7 +993,7 @@ void IPARPi::returnEmbeddedBuffer(unsigned int bufferId)
 
 void IPARPi::prepareISP(const ISPConfig &data)
 {
-	int64_t frameTimestamp = data.controls.get(controls::SensorTimestamp);
+	int64_t frameTimestamp = data.controls.get(controls::SensorTimestamp).value_or(0);
 	RPiController::Metadata lastMetadata;
 	Span<uint8_t> embeddedBuffer;
 

src/libcamera/pipeline/ipu3/ipu3.cpp

@@ -1145,7 +1145,7 @@ int PipelineHandlerIPU3::registerCameras()
 		/* Convert the sensor rotation to a transformation */
 		int32_t rotation = 0;
 		if (data->properties_.contains(properties::Rotation))
-			rotation = data->properties_.get(properties::Rotation);
+			rotation = *(data->properties_.get(properties::Rotation));
 		else
 			LOG(IPU3, Warning) << "Rotation control not exposed by "
 					   << cio2->sensor()->id()
@@ -1331,7 +1331,7 @@ void IPU3CameraData::imguOutputBufferReady(FrameBuffer *buffer)
 	request->metadata().set(controls::draft::PipelineDepth, 3);
 	/* \todo Actually apply the scaler crop region to the ImgU. */
 	if (request->controls().contains(controls::ScalerCrop))
-		cropRegion_ = request->controls().get(controls::ScalerCrop);
+		cropRegion_ = *(request->controls().get(controls::ScalerCrop));
 	request->metadata().set(controls::ScalerCrop, cropRegion_);
 
 	if (frameInfos_.tryComplete(info))
@@ -1424,7 +1424,7 @@ void IPU3CameraData::statBufferReady(FrameBuffer *buffer)
 		return;
 	}
 
-	ipa_->processStatsBuffer(info->id, request->metadata().get(controls::SensorTimestamp),
+	ipa_->processStatsBuffer(info->id, request->metadata().get(controls::SensorTimestamp).value_or(0),
 				 info->statBuffer->cookie(), info->effectiveSensorControls);
 }
 
@@ -1458,8 +1458,7 @@ void IPU3CameraData::frameStart(uint32_t sequence)
 	if (!request->controls().contains(controls::draft::TestPatternMode))
 		return;
 
-	const int32_t testPatternMode = request->controls().get(
+	const int32_t testPatternMode = *(request->controls().get(controls::draft::TestPatternMode));
-		controls::draft::TestPatternMode);
 
 	int ret = cio2_.sensor()->setTestPatternMode(
 		static_cast<controls::draft::TestPatternModeEnum>(testPatternMode));

src/libcamera/pipeline/raspberrypi/raspberrypi.cpp

@@ -364,7 +364,7 @@ CameraConfiguration::Status RPiCameraConfiguration::validate()
 	 * error means the platform can never run. Let's just print a warning
 	 * and continue regardless; the rotation is effectively set to zero.
 	 */
-	int32_t rotation = data_->sensor_->properties().get(properties::Rotation);
+	int32_t rotation = data_->sensor_->properties().get(properties::Rotation).value_or(0);
 	bool success;
 	Transform rotationTransform = transformFromRotation(rotation, &success);
 	if (!success)
@@ -1718,7 +1718,8 @@ void RPiCameraData::statsMetadataComplete(uint32_t bufferId, const ControlList &
 	 * V4L2_CID_NOTIFY_GAINS control (which means notifyGainsUnity_ is set).
 	 */
 	if (notifyGainsUnity_ && controls.contains(libcamera::controls::ColourGains)) {
-		libcamera::Span<const float> colourGains = controls.get(libcamera::controls::ColourGains);
+		libcamera::Span<const float> colourGains =
+			*controls.get(libcamera::controls::ColourGains);
 		/* The control wants linear gains in the order B, Gb, Gr, R. */
 		ControlList ctrls(sensor_->controls());
 		std::array<int32_t, 4> gains{
@@ -2053,7 +2054,7 @@ Rectangle RPiCameraData::scaleIspCrop(const Rectangle &ispCrop) const
 void RPiCameraData::applyScalerCrop(const ControlList &controls)
 {
 	if (controls.contains(controls::ScalerCrop)) {
-		Rectangle nativeCrop = controls.get<Rectangle>(controls::ScalerCrop);
+		Rectangle nativeCrop = *controls.get<Rectangle>(controls::ScalerCrop);
 
 		if (!nativeCrop.width || !nativeCrop.height)
 			nativeCrop = { 0, 0, 1, 1 };
@@ -2091,7 +2092,7 @@ void RPiCameraData::fillRequestMetadata(const ControlList &bufferControls,
 					Request *request)
 {
 	request->metadata().set(controls::SensorTimestamp,
-				bufferControls.get(controls::SensorTimestamp));
+				bufferControls.get(controls::SensorTimestamp).value_or(0));
 
 	request->metadata().set(controls::ScalerCrop, scalerCrop_);
 }

src/qcam/dng_writer.cpp

@@ -392,7 +392,7 @@ int DNGWriter::write(const char *filename, const Camera *camera,
 	TIFFSetField(tif, TIFFTAG_MAKE, "libcamera");
 
 	if (cameraProperties.contains(properties::Model)) {
-		std::string model = cameraProperties.get(properties::Model);
+		std::string model = *cameraProperties.get(properties::Model);
 		TIFFSetField(tif, TIFFTAG_MODEL, model.c_str());
 		/* \todo set TIFFTAG_UNIQUECAMERAMODEL. */
 	}
@@ -438,16 +438,15 @@ int DNGWriter::write(const char *filename, const Camera *camera,
 	const double eps = 1e-2;
 
 	if (metadata.contains(controls::ColourGains)) {
-		Span<const float> const &colourGains = metadata.get(controls::ColourGains);
+		const auto &colourGains = metadata.get(controls::ColourGains);
-		if (colourGains[0] > eps && colourGains[1] > eps) {
+		if ((*colourGains)[0] > eps && (*colourGains)[1] > eps) {
-			wbGain = Matrix3d::diag(colourGains[0], 1, colourGains[1]);
+			wbGain = Matrix3d::diag((*colourGains)[0], 1, (*colourGains)[1]);
-			neutral[0] = 1.0 / colourGains[0]; /* red */
+			neutral[0] = 1.0 / (*colourGains)[0]; /* red */
-			neutral[2] = 1.0 / colourGains[1]; /* blue */
+			neutral[2] = 1.0 / (*colourGains)[1]; /* blue */
 		}
 	}
 	if (metadata.contains(controls::ColourCorrectionMatrix)) {
-		Span<const float> const &coeffs = metadata.get(controls::ColourCorrectionMatrix);
+		Matrix3d ccmSupplied(*metadata.get(controls::ColourCorrectionMatrix));
-		Matrix3d ccmSupplied(coeffs);
 		if (ccmSupplied.determinant() > eps)
 			ccm = ccmSupplied;
 	}
@@ -515,7 +514,8 @@ int DNGWriter::write(const char *filename, const Camera *camera,
 	uint32_t whiteLevel = (1 << info->bitsPerSample) - 1;
 
 	if (metadata.contains(controls::SensorBlackLevels)) {
-		Span<const int32_t> levels = metadata.get(controls::SensorBlackLevels);
+		Span<const int32_t> levels =
+			*metadata.get(controls::SensorBlackLevels);
 
 		/*
 		 * The black levels control is specified in R, Gr, Gb, B order.
@@ -593,13 +593,13 @@ int DNGWriter::write(const char *filename, const Camera *camera,
 	TIFFSetField(tif, EXIFTAG_DATETIMEDIGITIZED, strTime);
 
 	if (metadata.contains(controls::AnalogueGain)) {
-		float gain = metadata.get(controls::AnalogueGain);
+		float gain = *metadata.get(controls::AnalogueGain);
 		uint16_t iso = std::min(std::max(gain * 100, 0.0f), 65535.0f);
 		TIFFSetField(tif, EXIFTAG_ISOSPEEDRATINGS, 1, &iso);
 	}
 
 	if (metadata.contains(controls::ExposureTime)) {
-		float exposureTime = metadata.get(controls::ExposureTime) / 1e6;
+		float exposureTime = *metadata.get(controls::ExposureTime) / 1e6;
 		TIFFSetField(tif, EXIFTAG_EXPOSURETIME, exposureTime);
 	}