AVCaptureDevice+Additions.swift

import AVFoundation

public typealias AVMediaType = String

public extension AVCaptureDevice {
    
    public class func device(mediaType: AVMediaType, position: AVCaptureDevicePosition) -> AVCaptureDevice? {
        let all = AVCaptureDevice.devicesWithMediaType(mediaType) as! [AVCaptureDevice]
        for dev in all {
            if dev.position == position {
                return dev
            }
        }
        return all.first
    }
    
    public func lockedConfiguration(var error: NSErrorPointer, operation: () -> ()) -> Bool {
        // TODO: Swift 2.0 reimplement
        if self.lockForConfiguration(nil) {
            operation()
            self.unlockForConfiguration()
            return true
        }
        return false
    }
    
    public func focusWithMode(focusMode: AVCaptureFocusMode, exposeWithMode exposureMode: AVCaptureExposureMode, atDevicePoint point: CGPoint, monitorSubjectAreaChange: Bool) {
        var error: NSError?
        self.lockedConfiguration(&error) {
            if self.focusPointOfInterestSupported && self.isFocusModeSupported(focusMode) {
                self.focusMode = focusMode
                self.focusPointOfInterest = point
            }
            if self.exposurePointOfInterestSupported && self.isExposureModeSupported(exposureMode) {
                self.exposureMode = exposureMode
                self.exposurePointOfInterest = point
            }
            self.subjectAreaChangeMonitoringEnabled = monitorSubjectAreaChange
        }
        if let error = error {
            print("-AVCaptureDevice.focusWithMode(_:, exposeWithMode:, atDevicePoint:, monitorSubjectAreaChange:) \(error)")
        }
        
    }
    
}