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

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

+// 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.
+
+#import "ios/chrome/browser/ui/qr_scanner/camera_controller.h"
+
+#include "base/ios/weak_nsobject.h"
+#include "base/logging.h"
+#include "base/mac/foundation_util.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/strings/stringprintf.h"
+#include "ios/chrome/common/ios_app_bundle_id_prefix.h"
+
+@interface CameraController ()<AVCaptureMetadataOutputObjectsDelegate> {
+  // The capture session for recording video and detecting QR codes.
+  base::scoped_nsobject<AVCaptureSession> _captureSession;
+  // The metadata output attached to the capture session.
+  base::scoped_nsobject<AVCaptureMetadataOutput> _metadataOutput;
+  // The delegate which receives the scanned result. All methods of this
+  // delegate should be called on the main queue.
+  base::WeakNSProtocol<id<CameraControllerDelegate>> _delegate;
+  // The queue for dispatching calls to |_captureSession|.
+  dispatch_queue_t _sessionQueue;
+}
+
+// The current state of the camera. The state is set to CAMERA_NOT_LOADED before
+// the camera is first loaded, and afterwards it is never CAMERA_NOT_LOADED.
+@property(nonatomic, readwrite, assign) qr_scanner::CameraState cameraState;
+// Redeclaration of |torchActive| to make the setter private.
+@property(nonatomic, readwrite, assign, getter=isTorchActive) BOOL torchActive;
+// The current availability of the torch.
+@property(nonatomic, readwrite, assign, getter=isTorchAvailable)
+    BOOL torchAvailable;
+
+// YES if |cameraState| is CAMERA_AVAILABLE.
+- (BOOL)isCameraAvailable;
+// Starts receiving notfications about changes to the capture session and to the
+// torch properties.
+- (void)startReceivingNotifications;
+// Stops receiving all notifications.
+- (void)stopReceivingNotifications;
+// Returns the camera attached to |_captureSession|.
+- (AVCaptureDevice*)getCamera;
+// Returns the AVCaptureVideoOrientation to compensate for the current
+// UIInterfaceOrientation. Defaults to AVCaptureVideoOrientationPortrait.
+- (AVCaptureVideoOrientation)videoOrientationForCurrentInterfaceOrientation;
+
+@end
+
+@implementation CameraController {
+  qr_scanner::CameraState _cameraState;
+  BOOL _torchActive;
+  BOOL _torchAvailable;
+  CGRect _viewportRect;
+}
+
+#pragma mark lifecycle
+
+- (instancetype)initWithDelegate:(id<CameraControllerDelegate>)delegate {
+  self = [super init];
+  if (self) {
+    DCHECK(delegate);
+    _cameraState = qr_scanner::CAMERA_NOT_LOADED;
+    _delegate.reset(delegate);
+    std::string queueName =
+        base::StringPrintf("%s.chrome.ios.QRScannerCaptureSessionQueue",
+                           BUILDFLAG(IOS_APP_BUNDLE_ID_PREFIX));
+    _sessionQueue =
+        dispatch_queue_create(queueName.c_str(), DISPATCH_QUEUE_SERIAL);
+    _torchAvailable = NO;
+    _torchActive = NO;
+    _viewportRect = CGRectNull;
+  }
+  return self;
+}
+
+- (void)dealloc {
+  [self stopReceivingNotifications];
+  dispatch_release(_sessionQueue);
+  [super dealloc];
+}
+
+#pragma mark public methods
+
+- (AVAuthorizationStatus)getAuthorizationStatus {
+  return [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
+}
+
+- (void)requestAuthorizationAndLoadCaptureSession:
+    (AVCaptureVideoPreviewLayer*)previewLayer {
+  DCHECK(previewLayer);
+  DCHECK([self getAuthorizationStatus] == AVAuthorizationStatusNotDetermined);
+  [AVCaptureDevice
+      requestAccessForMediaType:AVMediaTypeVideo
+              completionHandler:^void(BOOL granted) {
+                if (!granted) {
+                  [self setCameraState:qr_scanner::CAMERA_PERMISSION_DENIED];
+                } else {
+                  [self loadCaptureSession:previewLayer];
+                }
+              }];
+}
+
+- (void)setViewport:(CGRect)viewportRect {
+  dispatch_async(_sessionQueue, ^{
+    _viewportRect = viewportRect;
+    if (_metadataOutput) {
+      [_metadataOutput setRectOfInterest:_viewportRect];
+    }
+  });
+}
+
+- (void)resetVideoOrientation:(AVCaptureVideoPreviewLayer*)previewLayer {
+  DCHECK(previewLayer);
+  AVCaptureConnection* videoConnection = [previewLayer connection];
+  if ([videoConnection isVideoOrientationSupported]) {
+    [videoConnection setVideoOrientation:
+                         [self videoOrientationForCurrentInterfaceOrientation]];
+  }
+}
+
+- (void)startRecording {
+  dispatch_async(_sessionQueue, ^{
+    if ([self isCameraAvailable]) {
+      if (![_captureSession isRunning]) {
+        [_captureSession startRunning];
+      }
+    }
+  });
+}
+
+- (void)stopRecording {
+  dispatch_async(_sessionQueue, ^{
+    if ([self isCameraAvailable]) {
+      if ([_captureSession isRunning]) {
+        [_captureSession stopRunning];
+      }
+    }
+  });
+}
+
+- (void)setTorchMode:(AVCaptureTorchMode)mode {
+  dispatch_async(_sessionQueue, ^{
+    if (![self isCameraAvailable]) {
+      return;
+    }
+    AVCaptureDevice* camera = [self getCamera];
+    if (![camera isTorchModeSupported:mode]) {
+      return;
+    }
+    NSError* error = nil;
+    [camera lockForConfiguration:&error];
+    if (error) {
+      return;
+    }
+    [camera setTorchMode:mode];
+    [camera unlockForConfiguration];
+  });
+}
+
+#pragma mark private methods
+
+- (BOOL)isCameraAvailable {
+  return [self cameraState] == qr_scanner::CAMERA_AVAILABLE;
+}
+
+- (void)loadCaptureSession:(AVCaptureVideoPreviewLayer*)previewLayer {
+  DCHECK(previewLayer);
+  DCHECK([self cameraState] == qr_scanner::CAMERA_NOT_LOADED);
+  DCHECK([self getAuthorizationStatus] == AVAuthorizationStatusAuthorized);
+  dispatch_async(_sessionQueue, ^{
+    // Get the back camera.
+    NSArray* videoCaptureDevices =
+        [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
+    if ([videoCaptureDevices count] == 0) {
+      [self setCameraState:qr_scanner::CAMERA_UNAVAILABLE];
+      return;
+    }
+
+    NSUInteger cameraIndex = [videoCaptureDevices
+        indexOfObjectPassingTest:^BOOL(AVCaptureDevice* device, NSUInteger idx,
+                                       BOOL* stop) {
+          return device.position == AVCaptureDevicePositionBack;
+        }];
+
+    // Allow only the back camera.
+    if (cameraIndex == NSNotFound) {
+      [self setCameraState:qr_scanner::CAMERA_UNAVAILABLE];
+      return;
+    }
+    AVCaptureDevice* camera = videoCaptureDevices[cameraIndex];
+
+    // Configure camera input.
+    NSError* error = nil;
+    AVCaptureDeviceInput* videoInput =
+        [AVCaptureDeviceInput deviceInputWithDevice:camera error:&error];
+    if (error || !videoInput) {
+      [self setCameraState:qr_scanner::CAMERA_UNAVAILABLE];
+      return;
+    }
+
+    AVCaptureSession* session = [[[AVCaptureSession alloc] init] autorelease];
+    if (![session canAddInput:videoInput]) {
+      [self setCameraState:qr_scanner::CAMERA_UNAVAILABLE];
+      return;
+    }
+    [session addInput:videoInput];
+
+    // Configure metadata output.
+    AVCaptureMetadataOutput* metadataOutput =
+        [[[AVCaptureMetadataOutput alloc] init] autorelease];
+    [metadataOutput setMetadataObjectsDelegate:self
+                                         queue:dispatch_get_main_queue()];
+    if (![session canAddOutput:metadataOutput]) {
+      [self setCameraState:qr_scanner::CAMERA_UNAVAILABLE];
+      return;
+    }
+    [session addOutput:metadataOutput];
+    NSArray* availableCodeTypes = [metadataOutput availableMetadataObjectTypes];
+
+    // Require QR code recognition to be available.
+    if (![availableCodeTypes containsObject:AVMetadataObjectTypeQRCode]) {
+      [self setCameraState:qr_scanner::CAMERA_UNAVAILABLE];
+      return;
+    }
+    [metadataOutput setMetadataObjectTypes:availableCodeTypes];
+    _metadataOutput.reset([metadataOutput retain]);
+
+    _captureSession.reset([session retain]);
+    [self setCameraState:qr_scanner::CAMERA_AVAILABLE];
+    // Setup torchAvailable.
+    [self
+        setTorchAvailable:[camera hasTorch] &&
+                          [camera isTorchModeSupported:AVCaptureTorchModeOn] &&
+                          [camera isTorchModeSupported:AVCaptureTorchModeOff]];
+
+    [previewLayer setSession:_captureSession];
+    [previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
+    [self resetVideoOrientation:previewLayer];
+    dispatch_async(dispatch_get_main_queue(), ^{
+      [_delegate captureSessionIsConnected];
+      [self startRecording];
+    });
+    [self startReceivingNotifications];
+  });
+}
+
+- (void)startReceivingNotifications {
+  // Start receiving notifications about changes to the capture session.
+  [[NSNotificationCenter defaultCenter]
+      addObserver:self
+         selector:@selector(handleAVCaptureSessionRuntimeError:)
+             name:AVCaptureSessionRuntimeErrorNotification
+           object:_captureSession];
+
+  [[NSNotificationCenter defaultCenter]
+      addObserver:self
+         selector:@selector(handleAVCaptureSessionWasInterrupted:)
+             name:AVCaptureSessionWasInterruptedNotification
+           object:_captureSession];
+
+  [[NSNotificationCenter defaultCenter]
+      addObserver:self
+         selector:@selector(handleAVCaptureSessionInterruptionEnded:)
+             name:AVCaptureSessionInterruptionEndedNotification
+           object:_captureSession];
+
+  // Start receiving notifications about changes to the camera.
+  AVCaptureDevice* camera = [self getCamera];
+  DCHECK(camera);
+
+  [[NSNotificationCenter defaultCenter]
+      addObserver:self
+         selector:@selector(handleAVCaptureDeviceWasDisconnected:)
+             name:AVCaptureDeviceWasDisconnectedNotification
+           object:camera];
+
+  // Start receiving notifications about changes to the torch state.
+  [camera addObserver:self
+           forKeyPath:@"hasTorch"
+              options:NSKeyValueObservingOptionNew
+              context:nil];
+
+  [camera addObserver:self
+           forKeyPath:@"torchAvailable"
+              options:NSKeyValueObservingOptionNew
+              context:nil];
+
+  [camera addObserver:self
+           forKeyPath:@"torchActive"
+              options:NSKeyValueObservingOptionNew
+              context:nil];
+}
+
+- (void)stopReceivingNotifications {
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+  AVCaptureDevice* camera = [self getCamera];
+  [camera removeObserver:self forKeyPath:@"hasTorch"];
+  [camera removeObserver:self forKeyPath:@"torchAvailable"];
+  [camera removeObserver:self forKeyPath:@"torchActive"];
+}
+
+- (AVCaptureDevice*)getCamera {
+  AVCaptureDeviceInput* captureSessionInput =
+      [[_captureSession inputs] firstObject];
+  DCHECK(captureSessionInput != nil);
+  return [captureSessionInput device];
+}
+
+- (AVCaptureVideoOrientation)videoOrientationForCurrentInterfaceOrientation {
+  UIInterfaceOrientation orientation =
+      [[UIApplication sharedApplication] statusBarOrientation];
+  switch (orientation) {
+    case UIInterfaceOrientationUnknown:
+      return AVCaptureVideoOrientationPortrait;
+    default:
+      return static_cast<AVCaptureVideoOrientation>(orientation);
+  }
+}
+
+#pragma mark notification handlers
+
+- (void)handleAVCaptureSessionRuntimeError:(NSNotification*)notification {
+  dispatch_async(_sessionQueue, ^{
+    [self setCameraState:qr_scanner::CAMERA_UNAVAILABLE];
+  });
+}
+
+- (void)handleAVCaptureSessionWasInterrupted:(NSNotification*)notification {
+  dispatch_async(_sessionQueue, ^{
+    AVCaptureSessionInterruptionReason reason =
+        (AVCaptureSessionInterruptionReason)[[[notification userInfo]
+            valueForKey:AVCaptureSessionInterruptionReasonKey] integerValue];
+    switch (reason) {
+      case AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableInBackground:
+        // iOS automatically stops and restarts capture sessions when the app
+        // is backgrounded and foregrounded.
+        break;
+      case AVCaptureSessionInterruptionReasonVideoDeviceInUseByAnotherClient:
+        [self setCameraState:qr_scanner::CAMERA_IN_USE_BY_ANOTHER_APPLICATION];
+        break;
+      case AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableWithMultipleForegroundApps:
+        [self setCameraState:qr_scanner::MULTIPLE_FOREGROUND_APPS];
+        break;
+      case AVCaptureSessionInterruptionReasonAudioDeviceInUseByAnotherClient:
+        NOTREACHED();
+        break;
+    }
+  });
+}
+
+- (void)handleAVCaptureSessionInterruptionEnded:(NSNotification*)notification {
+  dispatch_async(_sessionQueue, ^{
+    if ([_captureSession isRunning]) {
+      [self setCameraState:qr_scanner::CAMERA_AVAILABLE];
+    }
+  });
+}
+
+- (void)handleAVCaptureDeviceWasDisconnected:(NSNotification*)notification {
+  dispatch_async(_sessionQueue, ^{
+    [self setCameraState:qr_scanner::CAMERA_UNAVAILABLE];
+  });
+}
+
+- (void)observeValueForKeyPath:(NSString*)keyPath
+                      ofObject:(id)object
+                        change:(NSDictionary<NSString*, id>*)change
+                       context:(void*)context {
+  if ([keyPath isEqualToString:@"hasTorch"] ||
+      [keyPath isEqualToString:@"torchAvailable"] ||
+      [keyPath isEqualToString:@"torchActive"]) {
+    AVCaptureDevice* camera = [self getCamera];
+    [self setTorchAvailable:([camera hasTorch] && [camera isTorchAvailable])];
+    [self setTorchActive:[camera isTorchActive]];
+  }
+}
+
+#pragma mark property implementation
+
+- (qr_scanner::CameraState)cameraState {
+  return _cameraState;
+}
+
+- (void)setCameraState:(qr_scanner::CameraState)state {
+  if (state == _cameraState) {
+    return;
+  }
+  _cameraState = state;
+  dispatch_async(dispatch_get_main_queue(), ^{
+    [_delegate cameraStateChanged:state];
+  });
+}
+
+- (BOOL)isTorchAvailable {
+  return _torchAvailable;
+}
+
+- (void)setTorchAvailable:(BOOL)available {
+  if (available == _torchAvailable) {
+    return;
+  }
+  _torchAvailable = available;
+  dispatch_async(dispatch_get_main_queue(), ^{
+    [_delegate torchAvailabilityChanged:available];
+  });
+}
+
+- (BOOL)isTorchActive {
+  return _torchActive;
+}
+
+- (void)setTorchActive:(BOOL)active {
+  if (active == _torchActive) {
+    return;
+  }
+  _torchActive = active;
+  dispatch_async(dispatch_get_main_queue(), ^{
+    [_delegate torchStateChanged:active];
+  });
+}
+
+#pragma mark AVCaptureMetadataOutputObjectsDelegate
+
+- (void)captureOutput:(AVCaptureOutput*)captureOutput
+    didOutputMetadataObjects:(NSArray*)metadataObjects
+              fromConnection:(AVCaptureConnection*)connection {
+  AVMetadataObject* metadataResult = [metadataObjects firstObject];
+  if (![metadataResult
+          isKindOfClass:[AVMetadataMachineReadableCodeObject class]]) {
+    return;
+  }
+  NSString* resultString =
+      [base::mac::ObjCCastStrict<AVMetadataMachineReadableCodeObject>(
+          metadataResult) stringValue];
+  if (resultString.length == 0) {
+    return;
+  }
+
+  dispatch_async(_sessionQueue, ^{
+    if ([_captureSession isRunning]) {
+      [_captureSession stopRunning];
+    }
+  });
+
+  // Check if the barcode can only contain digits. In this case, the result can
+  // be loaded immediately.
+  NSString* resultType = metadataResult.type;
+  BOOL isAllDigits =
+      [resultType isEqualToString:AVMetadataObjectTypeUPCECode] ||
+      [resultType isEqualToString:AVMetadataObjectTypeEAN8Code] ||
+      [resultType isEqualToString:AVMetadataObjectTypeEAN13Code] ||
+      [resultType isEqualToString:AVMetadataObjectTypeInterleaved2of5Code] ||
+      [resultType isEqualToString:AVMetadataObjectTypeITF14Code];
+
+  // Note: |captureOutput| is called on the main queue. This is specified by
+  // |setMetadataObjectsDelegate:queue:|.
+  [_delegate receiveQRScannerResult:resultString loadImmediately:isAllDigits];
+}
+
+@end