Upstream Chrome on iOS source code [6/11].

ios/chrome/browser/ui/qr_scanner/camera_controller.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef IOS_CHROME_BROWSER_UI_QR_SCANNER_CAMERA_CONTROLLER_H_
+#define IOS_CHROME_BROWSER_UI_QR_SCANNER_CAMERA_CONTROLLER_H_
+
+#import <AVFoundation/AVFoundation.h>
+#import <UIKit/UIKit.h>
+
+#include "base/ios/block_types.h"
+
+namespace qr_scanner {
+
+// Values to distinguish between different camera states to display the correct
+// view controller or system alert.
+// Note: no state encodes the state where the usage of the camera is prohibited
+// because the app is in the background. The reason is that iOS transparently
+// stops/starts the camera when the app enter/leaves the background.
+// See AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableInBackground for
+// more information.
+enum CameraState {
+  // Camera is loaded and available;
+  CAMERA_AVAILABLE = 0,
+  // The application cannot use the camera because it is in use exclusively by
+  // another application.
+  CAMERA_IN_USE_BY_ANOTHER_APPLICATION,
+  // The application cannot use the camera because video input is not supported
+  // if there are multiple foreground apps running.
+  MULTIPLE_FOREGROUND_APPS,
+  // The application does not have the permission to use the camera.
+  CAMERA_PERMISSION_DENIED,
+  // The camera is unavailable.
+  CAMERA_UNAVAILABLE,
+  // The camera was not yet loaded.
+  CAMERA_NOT_LOADED,
+};
+
+}  // namespace qr_scanner
+
+@protocol CameraControllerDelegate
+
+// Called on the main queue when the capture session is connected to the
+// preview.
+- (void)captureSessionIsConnected;
+// Called on the main queue when the camera state changes.
+- (void)cameraStateChanged:(qr_scanner::CameraState)state;
+// Called on the main queue when the torch state changes.
+- (void)torchStateChanged:(BOOL)torchIsOn;
+// Called on the main queue when the torch availability changes.
+- (void)torchAvailabilityChanged:(BOOL)torchIsAvailable;
+// Called when the scanner detects a valid code. The camera controller stops
+// recording when a result is scanned. A valid code is any non-empty string. If
+// |load| is YES, the result should be loaded immediately without requiring
+// additional user input. The value of |load| will only be YES for barcodes
+// which can only encode digits.
+- (void)receiveQRScannerResult:(NSString*)result loadImmediately:(BOOL)load;
+
+@end
+
+// The CameraController manages the AVCaptureSession, its inputs, outputs, and
+// notifications for the QRScannerViewController.
+@interface CameraController : NSObject
+
+// The current state of the torch.
+@property(nonatomic, readonly, assign, getter=isTorchActive) BOOL torchActive;
+
+- (instancetype)init NS_UNAVAILABLE;
+
+// Initializes the controller with the |delegate|.
+- (instancetype)initWithDelegate:(id<CameraControllerDelegate>)delegate
+    NS_DESIGNATED_INITIALIZER;
+
+// Returns the app's authorization in regards to the camera.
+- (AVAuthorizationStatus)getAuthorizationStatus;
+
+// Asks the user to grant the authorization to access the camera.
+// Should only be called when the current authorization status is
+// AVAuthorizationStatusNotDetermined.
+- (void)requestAuthorizationAndLoadCaptureSession:
+    (AVCaptureVideoPreviewLayer*)previewLayer;
+
+// Loads the camera and sets the value of |cameraState|.
+// Should only be called when the current authorization status is
+// AVAuthorizationStatusAuthorized.
+- (void)loadCaptureSession:(AVCaptureVideoPreviewLayer*)previewLayer;
+
+// Sets the rectangle in which codes are recognized to |viewportRect|. If the
+// metadata output object is not loaded, |viewportRect| will be set when the
+// output loads.
+- (void)setViewport:(CGRect)viewportRect;
+
+// Resets the video orientation to the current interface orientation.
+- (void)resetVideoOrientation:(AVCaptureVideoPreviewLayer*)previewLayer;
+
+// Starts the camera capture session. Does nothing if the camera is not
+// available.
+- (void)startRecording;
+
+// Stops the camera capture session. Does nothing if the camera is not
+// available.
+- (void)stopRecording;
+
+// Sets the camera's torch mode to |mode|. Does nothing if the camera is not
+// available or the torch mode is not supported.
+- (void)setTorchMode:(AVCaptureTorchMode)mode;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_QR_SCANNER_CAMERA_CONTROLLER_H_