content/browser/device_monitor_mac.mm

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/device_monitor_mac.h"
   6
   7 #import <QTKit/QTKit.h>
   8
   9 #include <set>
  10
  11 #include "base/bind_helpers.h"
  12 #include "base/logging.h"
  13 #include "base/mac/scoped_nsobject.h"
  14 #import "media/video/capture/mac/avfoundation_glue.h"
  15
  16 namespace {
  17
  18 // This class is used to keep track of system devices names and their types.
  19 class DeviceInfo {
  20  public:
  21   enum DeviceType {
  22     kAudio,
  23     kVideo,
  24     kMuxed,
  25     kUnknown,
  26     kInvalid
  27   };
  28
  29   DeviceInfo(std::string unique_id, DeviceType type)
  30       : unique_id_(unique_id), type_(type) {}
  31
  32   // Operator== is needed here to use this class in a std::find. A given
  33   // |unique_id_| always has the same |type_| so for comparison purposes the
  34   // latter can be safely ignored.
  35   bool operator==(const DeviceInfo& device) const {
  36     return unique_id_ == device.unique_id_;
  37   }
  38
  39   const std::string& unique_id() const { return unique_id_; }
  40   DeviceType type() const { return type_; }
  41
  42  private:
  43   std::string unique_id_;
  44   DeviceType type_;
  45   // Allow generated copy constructor and assignment.
  46 };
  47
  48 // Base abstract class used by DeviceMonitorMac to interact with either a QTKit
  49 // or an AVFoundation implementation of events and notifications.
  50 class DeviceMonitorMacImpl {
  51  public:
  52   explicit DeviceMonitorMacImpl(content::DeviceMonitorMac* monitor)
  53       : monitor_(monitor),
  54         cached_devices_(),
  55         device_arrival_(nil),
  56         device_removal_(nil) {
  57     DCHECK(monitor);
  58     // Initialise the devices_cache_ with a not-valid entry. For the case in
  59     // which there is one single device in the system and we get notified when
  60     // it gets removed, this will prevent the system from thinking that no
  61     // devices were added nor removed and not notifying the |monitor_|.
  62     cached_devices_.push_back(DeviceInfo("invalid", DeviceInfo::kInvalid));
  63   }
  64   virtual ~DeviceMonitorMacImpl() {}
  65
  66   virtual void OnDeviceChanged() = 0;
  67
  68   // Method called by the default notification center when a device is removed
  69   // or added to the system. It will compare the |cached_devices_| with the
  70   // current situation, update it, and, if there's an update, signal to
  71   // |monitor_| with the appropriate device type.
  72   void ConsolidateDevicesListAndNotify(
  73       const std::vector<DeviceInfo>& snapshot_devices);
  74
  75  protected:
  76   content::DeviceMonitorMac* monitor_;
  77   std::vector<DeviceInfo> cached_devices_;
  78
  79   // Handles to NSNotificationCenter block observers.
  80   id device_arrival_;
  81   id device_removal_;
  82
  83  private:
  84   DISALLOW_COPY_AND_ASSIGN(DeviceMonitorMacImpl);
  85 };
  86
  87 void DeviceMonitorMacImpl::ConsolidateDevicesListAndNotify(
  88     const std::vector<DeviceInfo>& snapshot_devices) {
  89   bool video_device_added = false;
  90   bool audio_device_added = false;
  91   bool video_device_removed = false;
  92   bool audio_device_removed = false;
  93
  94   // Compare the current system devices snapshot with the ones cached to detect
  95   // additions, present in the former but not in the latter. If we find a device
  96   // in snapshot_devices entry also present in cached_devices, we remove it from
  97   // the latter vector.
  98   std::vector<DeviceInfo>::const_iterator it;
  99   for (it = snapshot_devices.begin(); it != snapshot_devices.end(); ++it) {
 100     std::vector<DeviceInfo>::iterator cached_devices_iterator =
 101         std::find(cached_devices_.begin(), cached_devices_.end(), *it);
 102     if (cached_devices_iterator == cached_devices_.end()) {
 103       video_device_added |= ((it->type() == DeviceInfo::kVideo) ||
 104                              (it->type() == DeviceInfo::kMuxed));
 105       audio_device_added |= ((it->type() == DeviceInfo::kAudio) ||
 106                              (it->type() == DeviceInfo::kMuxed));
 107       DVLOG(1) << "Device has been added, id: " << it->unique_id();
 108     } else {
 109       cached_devices_.erase(cached_devices_iterator);
 110     }
 111   }
 112   // All the remaining entries in cached_devices are removed devices.
 113   for (it = cached_devices_.begin(); it != cached_devices_.end(); ++it) {
 114     video_device_removed |= ((it->type() == DeviceInfo::kVideo) ||
 115                              (it->type() == DeviceInfo::kMuxed) ||
 116                              (it->type() == DeviceInfo::kInvalid));
 117     audio_device_removed |= ((it->type() == DeviceInfo::kAudio) ||
 118                              (it->type() == DeviceInfo::kMuxed) ||
 119                              (it->type() == DeviceInfo::kInvalid));
 120     DVLOG(1) << "Device has been removed, id: " << it->unique_id();
 121   }
 122   // Update the cached devices with the current system snapshot.
 123   cached_devices_ = snapshot_devices;
 124
 125   if (video_device_added || video_device_removed)
 126     monitor_->NotifyDeviceChanged(base::SystemMonitor::DEVTYPE_VIDEO_CAPTURE);
 127   if (audio_device_added || audio_device_removed)
 128     monitor_->NotifyDeviceChanged(base::SystemMonitor::DEVTYPE_AUDIO_CAPTURE);
 129 }
 130
 131 class QTKitMonitorImpl : public DeviceMonitorMacImpl {
 132  public:
 133   explicit QTKitMonitorImpl(content::DeviceMonitorMac* monitor);
 134   virtual ~QTKitMonitorImpl();
 135
 136   virtual void OnDeviceChanged() OVERRIDE;
 137  private:
 138   void CountDevices();
 139   void OnAttributeChanged(NSNotification* notification);
 140
 141   id device_change_;
 142 };
 143
 144 QTKitMonitorImpl::QTKitMonitorImpl(content::DeviceMonitorMac* monitor)
 145     : DeviceMonitorMacImpl(monitor) {
 146   NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
 147   device_arrival_ =
 148       [nc addObserverForName:QTCaptureDeviceWasConnectedNotification
 149                       object:nil
 150                        queue:nil
 151                   usingBlock:^(NSNotification* notification) {
 152                       OnDeviceChanged();}];
 153   device_removal_ =
 154       [nc addObserverForName:QTCaptureDeviceWasDisconnectedNotification
 155                       object:nil
 156                        queue:nil
 157                   usingBlock:^(NSNotification* notification) {
 158                       OnDeviceChanged();}];
 159   device_change_ =
 160       [nc addObserverForName:QTCaptureDeviceAttributeDidChangeNotification
 161                       object:nil
 162                        queue:nil
 163                   usingBlock:^(NSNotification* notification) {
 164                       OnAttributeChanged(notification);}];
 165 }
 166
 167 QTKitMonitorImpl::~QTKitMonitorImpl() {
 168   NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
 169   [nc removeObserver:device_arrival_];
 170   [nc removeObserver:device_removal_];
 171   [nc removeObserver:device_change_];
 172 }
 173
 174 void QTKitMonitorImpl::OnAttributeChanged(
 175     NSNotification* notification) {
 176   if ([[[notification userInfo]
 177          objectForKey:QTCaptureDeviceChangedAttributeKey]
 178       isEqualToString:QTCaptureDeviceSuspendedAttribute]) {
 179     OnDeviceChanged();
 180   }
 181 }
 182
 183 void QTKitMonitorImpl::OnDeviceChanged() {
 184   std::vector<DeviceInfo> snapshot_devices;
 185
 186   NSArray* devices = [QTCaptureDevice inputDevices];
 187   for (QTCaptureDevice* device in devices) {
 188     DeviceInfo::DeviceType device_type = DeviceInfo::kUnknown;
 189     // Act as if suspended video capture devices are not attached.  For
 190     // example, a laptop's internal webcam is suspended when the lid is closed.
 191     if ([device hasMediaType:QTMediaTypeVideo] &&
 192         ![[device attributeForKey:QTCaptureDeviceSuspendedAttribute]
 193         boolValue]) {
 194       device_type = DeviceInfo::kVideo;
 195     } else if ([device hasMediaType:QTMediaTypeMuxed] &&
 196         ![[device attributeForKey:QTCaptureDeviceSuspendedAttribute]
 197         boolValue]) {
 198       device_type = DeviceInfo::kMuxed;
 199     } else if ([device hasMediaType:QTMediaTypeSound] &&
 200         ![[device attributeForKey:QTCaptureDeviceSuspendedAttribute]
 201         boolValue]) {
 202       device_type = DeviceInfo::kAudio;
 203     }
 204     snapshot_devices.push_back(
 205         DeviceInfo([[device uniqueID] UTF8String], device_type));
 206   }
 207   ConsolidateDevicesListAndNotify(snapshot_devices);
 208 }
 209
 210 // Forward declaration for use by CrAVFoundationDeviceObserver.
 211 class AVFoundationMonitorImpl;
 212
 213 }  // namespace
 214
 215 // This class is a Key-Value Observer (KVO) shim. It is needed because C++
 216 // classes cannot observe Key-Values directly. This class is used by
 217 // AVfoundationMonitorImpl and executed in its |device_task_runner_|, a.k.a.
 218 // "Device Thread". -stopObserving is called dutifully on -dealloc on UI thread.
 219 @interface CrAVFoundationDeviceObserver : NSObject {
 220  @private
 221   AVFoundationMonitorImpl* receiver_;
 222   // Member to keep track of the devices we are already monitoring.
 223   std::set<CrAVCaptureDevice*> monitoredDevices_;
 224 }
 225
 226 - (id)initWithChangeReceiver:(AVFoundationMonitorImpl*)receiver;
 227 - (void)startObserving:(CrAVCaptureDevice*)device;
 228 - (void)stopObserving:(CrAVCaptureDevice*)device;
 229
 230 @end
 231
 232 namespace {
 233
 234 // AVFoundation implementation of the Mac Device Monitor, registers as a global
 235 // device connect/disconnect observer and plugs suspend/wake up device observers
 236 // per device. This class is created and lives in UI thread; device enumeration
 237 // and operations involving |suspend_observer_| happen on |device_task_runner_|.
 238 class AVFoundationMonitorImpl : public DeviceMonitorMacImpl {
 239  public:
 240   AVFoundationMonitorImpl(
 241       content::DeviceMonitorMac* monitor,
 242       const scoped_refptr<base::SingleThreadTaskRunner>& device_task_runner);
 243   virtual ~AVFoundationMonitorImpl();
 244
 245   virtual void OnDeviceChanged() OVERRIDE;
 246
 247  private:
 248   void OnDeviceChangedOnDeviceThread(
 249       const scoped_refptr<base::MessageLoopProxy>& ui_thread);
 250   void StartObserverOnDeviceThread();
 251
 252   base::ThreadChecker thread_checker_;
 253
 254   // {Video,AudioInput}DeviceManager's "Device" thread task runner used for
 255   // device enumeration, valid after MediaStreamManager calls StartMonitoring().
 256   const scoped_refptr<base::SingleThreadTaskRunner> device_task_runner_;
 257
 258   // Created and executed in |device_task_runnner_|.
 259   base::scoped_nsobject<CrAVFoundationDeviceObserver> suspend_observer_;
 260
 261   DISALLOW_COPY_AND_ASSIGN(AVFoundationMonitorImpl);
 262 };
 263
 264 AVFoundationMonitorImpl::AVFoundationMonitorImpl(
 265     content::DeviceMonitorMac* monitor,
 266     const scoped_refptr<base::SingleThreadTaskRunner>& device_task_runner)
 267     : DeviceMonitorMacImpl(monitor),
 268       device_task_runner_(device_task_runner) {
 269   NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
 270   device_arrival_ =
 271       [nc addObserverForName:AVFoundationGlue::
 272           AVCaptureDeviceWasConnectedNotification()
 273                       object:nil
 274                        queue:nil
 275                   usingBlock:^(NSNotification* notification) {
 276                       OnDeviceChanged();}];
 277   device_removal_ =
 278       [nc addObserverForName:AVFoundationGlue::
 279           AVCaptureDeviceWasDisconnectedNotification()
 280                       object:nil
 281                        queue:nil
 282                   usingBlock:^(NSNotification* notification) {
 283                       OnDeviceChanged();}];
 284   device_task_runner_->PostTask(FROM_HERE,
 285       base::Bind(&AVFoundationMonitorImpl::StartObserverOnDeviceThread,
 286           base::Unretained(this)));
 287 }
 288
 289 AVFoundationMonitorImpl::~AVFoundationMonitorImpl() {
 290   NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
 291   [nc removeObserver:device_arrival_];
 292   [nc removeObserver:device_removal_];
 293 }
 294
 295 void AVFoundationMonitorImpl::OnDeviceChanged() {
 296   DCHECK(thread_checker_.CalledOnValidThread());
 297   device_task_runner_->PostTask(FROM_HERE,
 298       base::Bind(&AVFoundationMonitorImpl::OnDeviceChangedOnDeviceThread,
 299           base::Unretained(this),
 300           base::MessageLoop::current()->message_loop_proxy()));
 301 }
 302
 303 void AVFoundationMonitorImpl::OnDeviceChangedOnDeviceThread(
 304     const scoped_refptr<base::MessageLoopProxy>& ui_thread) {
 305   DCHECK(device_task_runner_->BelongsToCurrentThread());
 306   NSArray* devices = [AVCaptureDeviceGlue devices];
 307   std::vector<DeviceInfo> snapshot_devices;
 308   for (CrAVCaptureDevice* device in devices) {
 309     [suspend_observer_ startObserving:device];
 310     BOOL suspended = [device respondsToSelector:@selector(isSuspended)] &&
 311         [device isSuspended];
 312     DeviceInfo::DeviceType device_type = DeviceInfo::kUnknown;
 313     if ([device hasMediaType:AVFoundationGlue::AVMediaTypeVideo()]) {
 314       if (suspended)
 315         continue;
 316       device_type = DeviceInfo::kVideo;
 317     } else if ([device hasMediaType:AVFoundationGlue::AVMediaTypeMuxed()]) {
 318       device_type = suspended ? DeviceInfo::kAudio : DeviceInfo::kMuxed;
 319     } else if ([device hasMediaType:AVFoundationGlue::AVMediaTypeAudio()]) {
 320       device_type = DeviceInfo::kAudio;
 321     }
 322     snapshot_devices.push_back(DeviceInfo([[device uniqueID] UTF8String],
 323                                           device_type));
 324   }
 325   // Post the consolidation of enumerated devices to be done on UI thread.
 326   ui_thread->PostTask(FROM_HERE,
 327       base::Bind(&DeviceMonitorMacImpl::ConsolidateDevicesListAndNotify,
 328           base::Unretained(this), snapshot_devices));
 329 }
 330
 331 void AVFoundationMonitorImpl::StartObserverOnDeviceThread() {
 332   DCHECK(device_task_runner_->BelongsToCurrentThread());
 333   suspend_observer_.reset([[CrAVFoundationDeviceObserver alloc]
 334                                initWithChangeReceiver:this]);
 335   for (CrAVCaptureDevice* device in [AVCaptureDeviceGlue devices])
 336     [suspend_observer_ startObserving:device];
 337 }
 338
 339 }  // namespace
 340
 341 @implementation CrAVFoundationDeviceObserver
 342
 343 - (id)initWithChangeReceiver:(AVFoundationMonitorImpl*)receiver {
 344   if ((self = [super init])) {
 345     DCHECK(receiver != NULL);
 346     receiver_ = receiver;
 347   }
 348   return self;
 349 }
 350
 351 - (void)dealloc {
 352   std::set<CrAVCaptureDevice*>::iterator it = monitoredDevices_.begin();
 353   while (it != monitoredDevices_.end())
 354     [self stopObserving:*it++];
 355   [super dealloc];
 356 }
 357
 358 - (void)startObserving:(CrAVCaptureDevice*)device {
 359   DCHECK(device != nil);
 360   // Skip this device if there are already observers connected to it.
 361   if (std::find(monitoredDevices_.begin(), monitoredDevices_.end(), device) !=
 362           monitoredDevices_.end()) {
 363     return;
 364   }
 365   [device addObserver:self
 366            forKeyPath:@"suspended"
 367               options:0
 368               context:device];
 369   [device addObserver:self
 370            forKeyPath:@"connected"
 371               options:0
 372               context:device];
 373   monitoredDevices_.insert(device);
 374 }
 375
 376 - (void)stopObserving:(CrAVCaptureDevice*)device {
 377   DCHECK(device != nil);
 378   std::set<CrAVCaptureDevice*>::iterator found =
 379       std::find(monitoredDevices_.begin(), monitoredDevices_.end(), device);
 380   DCHECK(found != monitoredDevices_.end());
 381   [device removeObserver:self
 382               forKeyPath:@"suspended"];
 383   [device removeObserver:self
 384               forKeyPath:@"connected"];
 385   monitoredDevices_.erase(found);
 386 }
 387
 388 - (void)observeValueForKeyPath:(NSString*)keyPath
 389                       ofObject:(id)object
 390                         change:(NSDictionary*)change
 391                        context:(void*)context {
 392   if ([keyPath isEqual:@"suspended"])
 393     receiver_->OnDeviceChanged();
 394   if ([keyPath isEqual:@"connected"])
 395     [self stopObserving:static_cast<CrAVCaptureDevice*>(context)];
 396 }
 397
 398 @end  // @implementation CrAVFoundationDeviceObserver
 399
 400 namespace content {
 401
 402 DeviceMonitorMac::DeviceMonitorMac() {
 403   // Both QTKit and AVFoundation do not need to be fired up until the user
 404   // exercises a GetUserMedia. Bringing up either library and enumerating the
 405   // devices in the system is an operation taking in the range of hundred of ms,
 406   // so it is triggered explicitly from MediaStreamManager::StartMonitoring().
 407 }
 408
 409 DeviceMonitorMac::~DeviceMonitorMac() {}
 410
 411 void DeviceMonitorMac::StartMonitoring(
 412     const scoped_refptr<base::SingleThreadTaskRunner>& device_task_runner) {
 413   DCHECK(thread_checker_.CalledOnValidThread());
 414   if (AVFoundationGlue::IsAVFoundationSupported()) {
 415     DVLOG(1) << "Monitoring via AVFoundation";
 416     device_monitor_impl_.reset(new AVFoundationMonitorImpl(this,
 417                                                            device_task_runner));
 418   } else {
 419     DVLOG(1) << "Monitoring via QTKit";
 420     device_monitor_impl_.reset(new QTKitMonitorImpl(this));
 421   }
 422 }
 423
 424 void DeviceMonitorMac::NotifyDeviceChanged(
 425     base::SystemMonitor::DeviceType type) {
 426   DCHECK(thread_checker_.CalledOnValidThread());
 427   // TODO(xians): Remove the global variable for SystemMonitor.
 428   base::SystemMonitor::Get()->ProcessDevicesChanged(type);
 429 }
 430
 431 }  // namespace content