[RSDK-9864] Remove gostream middle-man dependency from webcam

components/camera/videosource/query.go

@@ -0,0 +1,225 @@
+package videosource
+
+import (
+	"math"
+	"strings"
+	"time"
+
+	"github.com/pion/mediadevices"
+	"github.com/pion/mediadevices/pkg/driver"
+	"github.com/pion/mediadevices/pkg/driver/availability"
+	"github.com/pion/mediadevices/pkg/driver/camera"
+	"github.com/pion/mediadevices/pkg/io/video"
+	"github.com/pion/mediadevices/pkg/prop"
+	"github.com/pkg/errors"
+
+	"go.viam.com/rdk/logging"
+)
+
+// Below is adapted from github.com/pion/mediadevices.
+// It is further adapted from gostream's query.go
+// However, this is the minimum code needed for webcam to work, placed in this directory.
+// This vastly improves the debugging and feature development experience, by not over-DRY-ing.
+
+// GetNamedVideoSource attempts to find a device (not a screen) by the given name.
+// If name is empty, it finds any device.
+func getReaderAndDriver(
+	name string,
+	constraints mediadevices.MediaStreamConstraints,
+	logger logging.Logger,
+) (video.Reader, driver.Driver, error) {
+	var ptr *string
+	if name == "" {
+		ptr = nil
+	} else {
+		ptr = &name
+	}
+	d, selectedMedia, err := getUserVideoDriver(constraints, ptr, logger)
+	if err != nil {
+		return nil, nil, err
+	}
+	reader, err := newReaderFromDriver(d, selectedMedia)
+	if err != nil {
+		return nil, nil, err
+	}
+	return reader, d, nil
+}
+
+func getUserVideoDriver(
+	constraints mediadevices.MediaStreamConstraints,
+	label *string,
+	logger logging.Logger,
+) (driver.Driver, prop.Media, error) {
+	var videoConstraints mediadevices.MediaTrackConstraints
+	if constraints.Video != nil {
+		constraints.Video(&videoConstraints)
+	}
+	return selectVideo(videoConstraints, label, logger)
+}
+
+func newReaderFromDriver(
+	videoDriver driver.Driver,
+	mediaProp prop.Media,
+) (video.Reader, error) {
+	recorder, ok := videoDriver.(driver.VideoRecorder)
+	if !ok {
+		return nil, errors.New("driver not a driver.VideoRecorder")
+	}
+
+	if ok, err := driver.IsAvailable(videoDriver); !errors.Is(err, availability.ErrUnimplemented) && !ok {
+		return nil, errors.Wrap(err, "video driver not available")
+	} else if driverStatus := videoDriver.Status(); driverStatus != driver.StateClosed {
+		return nil, errors.New("video driver in use")
+	} else if err := videoDriver.Open(); err != nil {
+		return nil, errors.Wrap(err, "cannot open video driver")
+	}
+
+	mediaProp.DiscardFramesOlderThan = time.Second
+	reader, err := recorder.VideoRecord(mediaProp)
+	if err != nil {
+		return nil, err
+	}
+	return reader, nil
+}
+
+func labelFilter(target string, useSep bool) driver.FilterFn {
+	return driver.FilterFn(func(d driver.Driver) bool {
+		if !useSep {
+			return d.Info().Label == target
+		}
+		labels := strings.Split(d.Info().Label, camera.LabelSeparator)
+		for _, label := range labels {
+			if label == target {
+				return true
+			}
+		}
+		return false
+	})
+}
+
+func selectVideo(
+	constraints mediadevices.MediaTrackConstraints,
+	label *string,
+	logger logging.Logger,
+) (driver.Driver, prop.Media, error) {
+	return selectBestDriver(getVideoFilterBase(), getVideoFilter(label), constraints, logger)
+}
+
+func getVideoFilterBase() driver.FilterFn {
+	typeFilter := driver.FilterVideoRecorder()
+	notScreenFilter := driver.FilterNot(driver.FilterDeviceType(driver.Screen))
+	return driver.FilterAnd(typeFilter, notScreenFilter)
+}
+
+func getVideoFilter(label *string) driver.FilterFn {
+	filter := getVideoFilterBase()
+	if label != nil {
+		filter = driver.FilterAnd(filter, labelFilter(*label, true))
+	}
+	return filter
+}
+
+// select implements SelectSettings algorithm.
+// Reference: https://w3c.github.io/mediacapture-main/#dfn-selectsettings
+func selectBestDriver(
+	baseFilter driver.FilterFn,
+	filter driver.FilterFn,
+	constraints mediadevices.MediaTrackConstraints,
+	logger logging.Logger,
+) (driver.Driver, prop.Media, error) {
+	var bestDriver driver.Driver
+	var bestProp prop.Media
+	minFitnessDist := math.Inf(1)
+
+	baseDrivers := driver.GetManager().Query(baseFilter)
+	logger.Debugw("before specific filter, we found the following drivers", "count", len(baseDrivers))
+	for _, d := range baseDrivers {
+		logger.Debugw(d.Info().Label, "priority", float32(d.Info().Priority), "type", d.Info().DeviceType)
+	}
+
+	driverProperties := queryDriverProperties(filter, logger)
+	if len(driverProperties) == 0 {
+		logger.Debugw("found no drivers matching filter")
+	} else {
+		logger.Debugw("found drivers matching specific filter", "count", len(driverProperties))
+	}
+	for d, props := range driverProperties {
+		priority := float64(d.Info().Priority)
+		logger.Debugw(
+			"considering driver",
+			"label", d.Info().Label,
+			"priority", priority)
+		for _, p := range props {
+			fitnessDist, ok := constraints.MediaConstraints.FitnessDistance(p)
+			if !ok {
+				logger.Debugw("driver does not satisfy any constraints", "label", d.Info().Label)
+				continue
+			}
+			fitnessDistWithPriority := fitnessDist - priority
+			logger.Debugw(
+				"driver properties satisfy some constraints",
+				"label", d.Info().Label,
+				"props", p,
+				"distance", fitnessDist,
+				"distance_with_priority", fitnessDistWithPriority)
+			if fitnessDistWithPriority < minFitnessDist {
+				minFitnessDist = fitnessDistWithPriority
+				bestDriver = d
+				bestProp = p
+			}
+		}
+	}
+
+	if bestDriver == nil {
+		return nil, prop.Media{}, errors.New("failed to find the best driver that fits the constraints")
+	}
+
+	logger.Debugw("winning driver", "label", bestDriver.Info().Label, "props", bestProp)
+	selectedMedia := prop.Media{}
+	selectedMedia.MergeConstraints(constraints.MediaConstraints)
+	selectedMedia.Merge(bestProp)
+	return bestDriver, selectedMedia, nil
+}
+
+func queryDriverProperties(
+	filter driver.FilterFn,
+	logger logging.Logger,
+) map[driver.Driver][]prop.Media {
+	var needToClose []driver.Driver
+	drivers := driver.GetManager().Query(filter)
+	m := make(map[driver.Driver][]prop.Media)
+
+	for _, d := range drivers {
+		var status string
+		isAvailable, err := driver.IsAvailable(d)
+		if errors.Is(err, availability.ErrUnimplemented) {
+			s := d.Status()
+			status = string(s)
+			isAvailable = s == driver.StateClosed
+		} else if err != nil {
+			status = err.Error()
+		}
+
+		if isAvailable {
+			err := d.Open()
+			if err != nil {
+				logger.Debugw("error opening driver for querying", "error", err)
+				// Skip this driver if we failed to open because we can't get the properties
+				continue
+			}
+			needToClose = append(needToClose, d)
+			m[d] = d.Properties()
+		} else {
+			logger.Debugw("driver not available", "name", d.Info().Name, "label", d.Info().Label, "status", status)
+		}
+	}
+
+	for _, d := range needToClose {
+		// Since it was closed, we should close it to avoid a leak
+		if err := d.Close(); err != nil {
+			logger.Errorw("error closing driver", "error", err)
+		}
+	}
+
+	return m
+}