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      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 // Any tasks that communicates with the portable device may take >100ms to
      6 // complete. Those tasks should be run on an blocking thread instead of the
      7 // UI thread.
      8 
      9 #include "chrome/browser/storage_monitor/portable_device_watcher_win.h"
     10 
     11 #include <dbt.h>
     12 #include <portabledevice.h>
     13 
     14 #include "base/files/file_path.h"
     15 #include "base/logging.h"
     16 #include "base/stl_util.h"
     17 #include "base/strings/string_util.h"
     18 #include "base/strings/utf_string_conversions.h"
     19 #include "base/threading/sequenced_worker_pool.h"
     20 #include "base/win/scoped_co_mem.h"
     21 #include "base/win/scoped_comptr.h"
     22 #include "base/win/scoped_propvariant.h"
     23 #include "chrome/browser/storage_monitor/media_storage_util.h"
     24 #include "chrome/browser/storage_monitor/removable_device_constants.h"
     25 #include "chrome/browser/storage_monitor/storage_info.h"
     26 #include "content/public/browser/browser_thread.h"
     27 
     28 namespace chrome {
     29 
     30 namespace {
     31 
     32 // Name of the client application that communicates with the MTP device.
     33 const char16 kClientName[] = L"Chromium";
     34 
     35 // Name of the sequenced task runner.
     36 const char kMediaTaskRunnerName[] = "media-task-runner";
     37 
     38 // Returns true if |data| represents a class of portable devices.
     39 bool IsPortableDeviceStructure(LPARAM data) {
     40   DEV_BROADCAST_HDR* broadcast_hdr =
     41       reinterpret_cast<DEV_BROADCAST_HDR*>(data);
     42   if (!broadcast_hdr ||
     43       (broadcast_hdr->dbch_devicetype != DBT_DEVTYP_DEVICEINTERFACE)) {
     44     return false;
     45   }
     46 
     47   GUID guidDevInterface = GUID_NULL;
     48   if (FAILED(CLSIDFromString(kWPDDevInterfaceGUID, &guidDevInterface)))
     49     return false;
     50   DEV_BROADCAST_DEVICEINTERFACE* dev_interface =
     51       reinterpret_cast<DEV_BROADCAST_DEVICEINTERFACE*>(data);
     52   return (IsEqualGUID(dev_interface->dbcc_classguid, guidDevInterface) != 0);
     53 }
     54 
     55 // Returns the portable device plug and play device ID string.
     56 string16 GetPnpDeviceId(LPARAM data) {
     57   DEV_BROADCAST_DEVICEINTERFACE* dev_interface =
     58       reinterpret_cast<DEV_BROADCAST_DEVICEINTERFACE*>(data);
     59   if (!dev_interface)
     60     return string16();
     61   string16 device_id(dev_interface->dbcc_name);
     62   DCHECK(IsStringASCII(device_id));
     63   return StringToLowerASCII(device_id);
     64 }
     65 
     66 // Gets the friendly name of the device specified by the |pnp_device_id|. On
     67 // success, returns true and fills in |name|.
     68 bool GetFriendlyName(const string16& pnp_device_id,
     69                      IPortableDeviceManager* device_manager,
     70                      string16* name) {
     71   DCHECK(device_manager);
     72   DCHECK(name);
     73   DWORD name_len = 0;
     74   HRESULT hr = device_manager->GetDeviceFriendlyName(pnp_device_id.c_str(),
     75                                                      NULL, &name_len);
     76   if (FAILED(hr))
     77     return false;
     78 
     79   hr = device_manager->GetDeviceFriendlyName(
     80       pnp_device_id.c_str(), WriteInto(name, name_len), &name_len);
     81   return (SUCCEEDED(hr) && !name->empty());
     82 }
     83 
     84 // Gets the manufacturer name of the device specified by the |pnp_device_id|.
     85 // On success, returns true and fills in |name|.
     86 bool GetManufacturerName(const string16& pnp_device_id,
     87                          IPortableDeviceManager* device_manager,
     88                          string16* name) {
     89   DCHECK(device_manager);
     90   DCHECK(name);
     91   DWORD name_len = 0;
     92   HRESULT hr = device_manager->GetDeviceManufacturer(pnp_device_id.c_str(),
     93                                                      NULL, &name_len);
     94   if (FAILED(hr))
     95     return false;
     96 
     97   hr = device_manager->GetDeviceManufacturer(pnp_device_id.c_str(),
     98                                              WriteInto(name, name_len),
     99                                              &name_len);
    100   return (SUCCEEDED(hr) && !name->empty());
    101 }
    102 
    103 // Gets the description of the device specified by the |pnp_device_id|. On
    104 // success, returns true and fills in |description|.
    105 bool GetDeviceDescription(const string16& pnp_device_id,
    106                           IPortableDeviceManager* device_manager,
    107                           string16* description) {
    108   DCHECK(device_manager);
    109   DCHECK(description);
    110   DWORD desc_len = 0;
    111   HRESULT hr = device_manager->GetDeviceDescription(pnp_device_id.c_str(), NULL,
    112                                                     &desc_len);
    113   if (FAILED(hr))
    114     return false;
    115 
    116   hr = device_manager->GetDeviceDescription(pnp_device_id.c_str(),
    117                                             WriteInto(description, desc_len),
    118                                             &desc_len);
    119   return (SUCCEEDED(hr) && !description->empty());
    120 }
    121 
    122 // On success, returns true and updates |client_info| with a reference to an
    123 // IPortableDeviceValues interface that holds information about the
    124 // application that communicates with the device.
    125 bool GetClientInformation(
    126     base::win::ScopedComPtr<IPortableDeviceValues>* client_info) {
    127   HRESULT hr = client_info->CreateInstance(__uuidof(PortableDeviceValues),
    128                                            NULL, CLSCTX_INPROC_SERVER);
    129   if (FAILED(hr)) {
    130     DPLOG(ERROR) << "Failed to create an instance of IPortableDeviceValues";
    131     return false;
    132   }
    133 
    134   // Attempt to set client details.
    135   (*client_info)->SetStringValue(WPD_CLIENT_NAME, kClientName);
    136   (*client_info)->SetUnsignedIntegerValue(WPD_CLIENT_MAJOR_VERSION, 0);
    137   (*client_info)->SetUnsignedIntegerValue(WPD_CLIENT_MINOR_VERSION, 0);
    138   (*client_info)->SetUnsignedIntegerValue(WPD_CLIENT_REVISION, 0);
    139   (*client_info)->SetUnsignedIntegerValue(
    140       WPD_CLIENT_SECURITY_QUALITY_OF_SERVICE, SECURITY_IMPERSONATION);
    141   (*client_info)->SetUnsignedIntegerValue(WPD_CLIENT_DESIRED_ACCESS,
    142                                           GENERIC_READ);
    143   return true;
    144 }
    145 
    146 // Opens the device for communication. |pnp_device_id| specifies the plug and
    147 // play device ID string. On success, returns true and updates |device| with a
    148 // reference to the portable device interface.
    149 bool SetUp(const string16& pnp_device_id,
    150            base::win::ScopedComPtr<IPortableDevice>* device) {
    151   base::win::ScopedComPtr<IPortableDeviceValues> client_info;
    152   if (!GetClientInformation(&client_info))
    153     return false;
    154 
    155   HRESULT hr = device->CreateInstance(__uuidof(PortableDevice), NULL,
    156                                       CLSCTX_INPROC_SERVER);
    157   if (FAILED(hr)) {
    158     DPLOG(ERROR) << "Failed to create an instance of IPortableDevice";
    159     return false;
    160   }
    161 
    162   hr = (*device)->Open(pnp_device_id.c_str(), client_info.get());
    163   if (SUCCEEDED(hr))
    164     return true;
    165 
    166   if (hr == E_ACCESSDENIED)
    167     DPLOG(ERROR) << "Access denied to open the device";
    168   return false;
    169 }
    170 
    171 // Returns the unique id property key of the object specified by the
    172 // |object_id|.
    173 REFPROPERTYKEY GetUniqueIdPropertyKey(const string16& object_id) {
    174   return (object_id == WPD_DEVICE_OBJECT_ID) ?
    175       WPD_DEVICE_SERIAL_NUMBER : WPD_OBJECT_PERSISTENT_UNIQUE_ID;
    176 }
    177 
    178 // On success, returns true and populates |properties_to_read| with the
    179 // property key of the object specified by the |object_id|.
    180 bool PopulatePropertyKeyCollection(
    181     const string16& object_id,
    182     base::win::ScopedComPtr<IPortableDeviceKeyCollection>* properties_to_read) {
    183   HRESULT hr = properties_to_read->CreateInstance(
    184       __uuidof(PortableDeviceKeyCollection), NULL, CLSCTX_INPROC_SERVER);
    185   if (FAILED(hr)) {
    186     DPLOG(ERROR) << "Failed to create IPortableDeviceKeyCollection instance";
    187     return false;
    188   }
    189   REFPROPERTYKEY key = GetUniqueIdPropertyKey(object_id);
    190   hr = (*properties_to_read)->Add(key);
    191   return SUCCEEDED(hr);
    192 }
    193 
    194 // Wrapper function to get content property string value.
    195 bool GetStringPropertyValue(IPortableDeviceValues* properties_values,
    196                             REFPROPERTYKEY key,
    197                             string16* value) {
    198   DCHECK(properties_values);
    199   DCHECK(value);
    200   base::win::ScopedCoMem<char16> buffer;
    201   HRESULT hr = properties_values->GetStringValue(key, &buffer);
    202   if (FAILED(hr))
    203     return false;
    204   *value = static_cast<const char16*>(buffer);
    205   return true;
    206 }
    207 
    208 // Constructs a unique identifier for the object specified by the |object_id|.
    209 // On success, returns true and fills in |unique_id|.
    210 bool GetObjectUniqueId(IPortableDevice* device,
    211                        const string16& object_id,
    212                        string16* unique_id) {
    213   DCHECK(device);
    214   DCHECK(unique_id);
    215   base::win::ScopedComPtr<IPortableDeviceContent> content;
    216   HRESULT hr = device->Content(content.Receive());
    217   if (FAILED(hr)) {
    218     DPLOG(ERROR) << "Failed to get IPortableDeviceContent interface";
    219     return false;
    220   }
    221 
    222   base::win::ScopedComPtr<IPortableDeviceProperties> properties;
    223   hr = content->Properties(properties.Receive());
    224   if (FAILED(hr)) {
    225     DPLOG(ERROR) << "Failed to get IPortableDeviceProperties interface";
    226     return false;
    227   }
    228 
    229   base::win::ScopedComPtr<IPortableDeviceKeyCollection> properties_to_read;
    230   if (!PopulatePropertyKeyCollection(object_id, &properties_to_read))
    231     return false;
    232 
    233   base::win::ScopedComPtr<IPortableDeviceValues> properties_values;
    234   if (FAILED(properties->GetValues(object_id.c_str(),
    235                                    properties_to_read.get(),
    236                                    properties_values.Receive()))) {
    237     return false;
    238   }
    239 
    240   REFPROPERTYKEY key = GetUniqueIdPropertyKey(object_id);
    241   return GetStringPropertyValue(properties_values.get(), key, unique_id);
    242 }
    243 
    244 // Constructs the device storage unique identifier using |device_serial_num| and
    245 // |storage_id|. On success, returns true and fills in |device_storage_id|.
    246 bool ConstructDeviceStorageUniqueId(const string16& device_serial_num,
    247                                     const string16& storage_id,
    248                                     std::string* device_storage_id) {
    249   if (device_serial_num.empty() && storage_id.empty())
    250     return false;
    251 
    252   DCHECK(device_storage_id);
    253   *device_storage_id = StorageInfo::MakeDeviceId(
    254        StorageInfo::MTP_OR_PTP,
    255        UTF16ToUTF8(storage_id + L':' + device_serial_num));
    256   return true;
    257 }
    258 
    259 // Gets a list of removable storage object identifiers present in |device|.
    260 // On success, returns true and fills in |storage_object_ids|.
    261 bool GetRemovableStorageObjectIds(
    262     IPortableDevice* device,
    263     PortableDeviceWatcherWin::StorageObjectIDs* storage_object_ids) {
    264   DCHECK(device);
    265   DCHECK(storage_object_ids);
    266   base::win::ScopedComPtr<IPortableDeviceCapabilities> capabilities;
    267   HRESULT hr = device->Capabilities(capabilities.Receive());
    268   if (FAILED(hr)) {
    269     DPLOG(ERROR) << "Failed to get IPortableDeviceCapabilities interface";
    270     return false;
    271   }
    272 
    273   base::win::ScopedComPtr<IPortableDevicePropVariantCollection> storage_ids;
    274   hr = capabilities->GetFunctionalObjects(WPD_FUNCTIONAL_CATEGORY_STORAGE,
    275                                           storage_ids.Receive());
    276   if (FAILED(hr)) {
    277     DPLOG(ERROR) << "Failed to get IPortableDevicePropVariantCollection";
    278     return false;
    279   }
    280 
    281   DWORD num_storage_obj_ids = 0;
    282   hr = storage_ids->GetCount(&num_storage_obj_ids);
    283   if (FAILED(hr))
    284     return false;
    285 
    286   for (DWORD index = 0; index < num_storage_obj_ids; ++index) {
    287     base::win::ScopedPropVariant object_id;
    288     hr = storage_ids->GetAt(index, object_id.Receive());
    289     if (SUCCEEDED(hr) && object_id.get().vt == VT_LPWSTR &&
    290         object_id.get().pwszVal != NULL) {
    291       storage_object_ids->push_back(object_id.get().pwszVal);
    292     }
    293   }
    294   return true;
    295 }
    296 
    297 // Returns true if the portable device belongs to a mass storage class.
    298 // |pnp_device_id| specifies the plug and play device id.
    299 // |device_name| specifies the name of the device.
    300 bool IsMassStoragePortableDevice(const string16& pnp_device_id,
    301                                  const string16& device_name) {
    302   // Based on testing, if the pnp device id starts with "\\?\wpdbusenumroot#",
    303   // then the attached device belongs to a mass storage class.
    304   if (StartsWith(pnp_device_id, L"\\\\?\\wpdbusenumroot#", false))
    305     return true;
    306 
    307   // If the device is a volume mounted device, |device_name| will be
    308   // the volume name.
    309   return ((device_name.length() >= 2) && (device_name[1] == L':') &&
    310       (((device_name[0] >= L'A') && (device_name[0] <= L'Z')) ||
    311           ((device_name[0] >= L'a') && (device_name[0] <= L'z'))));
    312 }
    313 
    314 // Returns the name of the device specified by |pnp_device_id|.
    315 string16 GetDeviceNameOnBlockingThread(
    316     IPortableDeviceManager* portable_device_manager,
    317     const string16& pnp_device_id) {
    318   DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
    319   DCHECK(portable_device_manager);
    320   string16 name;
    321   GetFriendlyName(pnp_device_id, portable_device_manager, &name) ||
    322       GetDeviceDescription(pnp_device_id, portable_device_manager, &name) ||
    323       GetManufacturerName(pnp_device_id, portable_device_manager, &name);
    324   return name;
    325 }
    326 
    327 // Access the device and gets the device storage details. On success, returns
    328 // true and populates |storage_objects| with device storage details.
    329 bool GetDeviceStorageObjectsOnBlockingThread(
    330     const string16& pnp_device_id,
    331     PortableDeviceWatcherWin::StorageObjects* storage_objects) {
    332   DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
    333   DCHECK(storage_objects);
    334   base::win::ScopedComPtr<IPortableDevice> device;
    335   if (!SetUp(pnp_device_id, &device))
    336     return false;
    337 
    338   string16 device_serial_num;
    339   if (!GetObjectUniqueId(device.get(), WPD_DEVICE_OBJECT_ID,
    340                          &device_serial_num)) {
    341     return false;
    342   }
    343 
    344   PortableDeviceWatcherWin::StorageObjectIDs storage_obj_ids;
    345   if (!GetRemovableStorageObjectIds(device.get(), &storage_obj_ids))
    346     return false;
    347   for (PortableDeviceWatcherWin::StorageObjectIDs::const_iterator id_iter =
    348        storage_obj_ids.begin(); id_iter != storage_obj_ids.end(); ++id_iter) {
    349     string16 storage_persistent_id;
    350     if (!GetObjectUniqueId(device.get(), *id_iter, &storage_persistent_id))
    351       continue;
    352 
    353     std::string device_storage_id;
    354     if (ConstructDeviceStorageUniqueId(device_serial_num, storage_persistent_id,
    355                                        &device_storage_id)) {
    356       storage_objects->push_back(PortableDeviceWatcherWin::DeviceStorageObject(
    357           *id_iter, device_storage_id));
    358     }
    359   }
    360   return true;
    361 }
    362 
    363 // Accesses the device and gets the device details (name, storage info, etc).
    364 // On success returns true and fills in |device_details|. On failure, returns
    365 // false. |pnp_device_id| specifies the plug and play device ID string.
    366 bool GetDeviceInfoOnBlockingThread(
    367     IPortableDeviceManager* portable_device_manager,
    368     const string16& pnp_device_id,
    369     PortableDeviceWatcherWin::DeviceDetails* device_details) {
    370   DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
    371   DCHECK(portable_device_manager);
    372   DCHECK(device_details);
    373   DCHECK(!pnp_device_id.empty());
    374   device_details->name = GetDeviceNameOnBlockingThread(portable_device_manager,
    375                                                        pnp_device_id);
    376   if (IsMassStoragePortableDevice(pnp_device_id, device_details->name))
    377     return false;
    378 
    379   device_details->location = pnp_device_id;
    380   PortableDeviceWatcherWin::StorageObjects storage_objects;
    381   return GetDeviceStorageObjectsOnBlockingThread(
    382       pnp_device_id, &device_details->storage_objects);
    383 }
    384 
    385 // Wrapper function to get an instance of portable device manager. On success,
    386 // returns true and fills in |portable_device_mgr|. On failure, returns false.
    387 bool GetPortableDeviceManager(
    388   base::win::ScopedComPtr<IPortableDeviceManager>* portable_device_mgr) {
    389   DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
    390   HRESULT hr = portable_device_mgr->CreateInstance(
    391       __uuidof(PortableDeviceManager), NULL, CLSCTX_INPROC_SERVER);
    392   if (SUCCEEDED(hr))
    393     return true;
    394 
    395   // Either there is no portable device support (Windows XP with old versions of
    396   // Media Player) or the thread does not have COM initialized.
    397   DCHECK_NE(CO_E_NOTINITIALIZED, hr);
    398   return false;
    399 }
    400 
    401 // Enumerates the attached portable devices. On success, returns true and fills
    402 // in |devices| with the attached portable device details. On failure, returns
    403 // false.
    404 bool EnumerateAttachedDevicesOnBlockingThread(
    405     PortableDeviceWatcherWin::Devices* devices) {
    406   DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
    407   DCHECK(devices);
    408   base::win::ScopedComPtr<IPortableDeviceManager> portable_device_mgr;
    409   if (!GetPortableDeviceManager(&portable_device_mgr))
    410     return false;
    411 
    412   // Get the total number of devices found on the system.
    413   DWORD pnp_device_count = 0;
    414   HRESULT hr = portable_device_mgr->GetDevices(NULL, &pnp_device_count);
    415   if (FAILED(hr))
    416     return false;
    417 
    418   scoped_ptr<char16*[]> pnp_device_ids(new char16*[pnp_device_count]);
    419   hr = portable_device_mgr->GetDevices(pnp_device_ids.get(), &pnp_device_count);
    420   if (FAILED(hr))
    421     return false;
    422 
    423   for (DWORD index = 0; index < pnp_device_count; ++index) {
    424     PortableDeviceWatcherWin::DeviceDetails device_details;
    425     if (GetDeviceInfoOnBlockingThread(
    426         portable_device_mgr, pnp_device_ids[index], &device_details))
    427       devices->push_back(device_details);
    428     CoTaskMemFree(pnp_device_ids[index]);
    429   }
    430   return !devices->empty();
    431 }
    432 
    433 // Handles the device attach event message on a media task runner.
    434 // |pnp_device_id| specifies the attached plug and play device ID string. On
    435 // success, returns true and populates |device_details| with device information.
    436 // On failure, returns false.
    437 bool HandleDeviceAttachedEventOnBlockingThread(
    438     const string16& pnp_device_id,
    439     PortableDeviceWatcherWin::DeviceDetails* device_details) {
    440   DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
    441   DCHECK(device_details);
    442   base::win::ScopedComPtr<IPortableDeviceManager> portable_device_mgr;
    443   if (!GetPortableDeviceManager(&portable_device_mgr))
    444     return false;
    445   // Sometimes, portable device manager doesn't have the new device details.
    446   // Refresh the manager device list to update its details.
    447   portable_device_mgr->RefreshDeviceList();
    448   return GetDeviceInfoOnBlockingThread(portable_device_mgr, pnp_device_id,
    449                                        device_details);
    450 }
    451 
    452 // Registers |hwnd| to receive portable device notification details. On success,
    453 // returns the device notifications handle else returns NULL.
    454 HDEVNOTIFY RegisterPortableDeviceNotification(HWND hwnd) {
    455   GUID dev_interface_guid = GUID_NULL;
    456   HRESULT hr = CLSIDFromString(kWPDDevInterfaceGUID, &dev_interface_guid);
    457   if (FAILED(hr))
    458     return NULL;
    459   DEV_BROADCAST_DEVICEINTERFACE db = {
    460       sizeof(DEV_BROADCAST_DEVICEINTERFACE),
    461       DBT_DEVTYP_DEVICEINTERFACE,
    462       0,
    463       dev_interface_guid
    464   };
    465   return RegisterDeviceNotification(hwnd, &db, DEVICE_NOTIFY_WINDOW_HANDLE);
    466 }
    467 
    468 }  // namespace
    469 
    470 
    471 // PortableDeviceWatcherWin ---------------------------------------------------
    472 
    473 PortableDeviceWatcherWin::DeviceStorageObject::DeviceStorageObject(
    474     const string16& temporary_id,
    475     const std::string& persistent_id)
    476     : object_temporary_id(temporary_id),
    477       object_persistent_id(persistent_id) {
    478 }
    479 
    480 PortableDeviceWatcherWin::PortableDeviceWatcherWin()
    481     : notifications_(NULL),
    482       storage_notifications_(NULL),
    483       weak_ptr_factory_(this) {
    484 }
    485 
    486 PortableDeviceWatcherWin::~PortableDeviceWatcherWin() {
    487   UnregisterDeviceNotification(notifications_);
    488 }
    489 
    490 void PortableDeviceWatcherWin::Init(HWND hwnd) {
    491   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
    492   notifications_ = RegisterPortableDeviceNotification(hwnd);
    493   base::SequencedWorkerPool* pool = content::BrowserThread::GetBlockingPool();
    494   media_task_runner_ = pool->GetSequencedTaskRunnerWithShutdownBehavior(
    495       pool->GetNamedSequenceToken(kMediaTaskRunnerName),
    496       base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
    497   EnumerateAttachedDevices();
    498 }
    499 
    500 void PortableDeviceWatcherWin::OnWindowMessage(UINT event_type, LPARAM data) {
    501   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
    502   if (!IsPortableDeviceStructure(data))
    503     return;
    504 
    505   string16 device_id = GetPnpDeviceId(data);
    506   if (event_type == DBT_DEVICEARRIVAL)
    507     HandleDeviceAttachEvent(device_id);
    508   else if (event_type == DBT_DEVICEREMOVECOMPLETE)
    509     HandleDeviceDetachEvent(device_id);
    510 }
    511 
    512 bool PortableDeviceWatcherWin::GetMTPStorageInfoFromDeviceId(
    513     const std::string& storage_device_id,
    514     string16* device_location,
    515     string16* storage_object_id) const {
    516   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
    517   DCHECK(device_location);
    518   DCHECK(storage_object_id);
    519   MTPStorageMap::const_iterator storage_map_iter =
    520       storage_map_.find(storage_device_id);
    521   if (storage_map_iter == storage_map_.end())
    522     return false;
    523 
    524   MTPDeviceMap::const_iterator device_iter =
    525       device_map_.find(storage_map_iter->second.location());
    526   if (device_iter == device_map_.end())
    527     return false;
    528   const StorageObjects& storage_objects = device_iter->second;
    529   for (StorageObjects::const_iterator storage_object_iter =
    530        storage_objects.begin(); storage_object_iter != storage_objects.end();
    531        ++storage_object_iter) {
    532     if (storage_device_id == storage_object_iter->object_persistent_id) {
    533       *device_location = storage_map_iter->second.location();
    534       *storage_object_id = storage_object_iter->object_temporary_id;
    535       return true;
    536     }
    537   }
    538   return false;
    539 }
    540 
    541 // static
    542 string16 PortableDeviceWatcherWin::GetStoragePathFromStorageId(
    543     const std::string& storage_unique_id) {
    544   // Construct a dummy device path using the storage name. This is only used
    545   // for registering the device media file system.
    546   DCHECK(!storage_unique_id.empty());
    547   return UTF8ToUTF16("\\\\" + storage_unique_id);
    548 }
    549 
    550 void PortableDeviceWatcherWin::SetNotifications(
    551     StorageMonitor::Receiver* notifications) {
    552   storage_notifications_ = notifications;
    553 }
    554 
    555 void PortableDeviceWatcherWin::EjectDevice(
    556     const std::string& device_id,
    557     base::Callback<void(StorageMonitor::EjectStatus)> callback) {
    558   callback.Run(chrome::StorageMonitor::EJECT_FAILURE);
    559 }
    560 
    561 void PortableDeviceWatcherWin::EnumerateAttachedDevices() {
    562   DCHECK(media_task_runner_.get());
    563   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
    564   Devices* devices = new Devices;
    565   base::PostTaskAndReplyWithResult(
    566       media_task_runner_,
    567       FROM_HERE,
    568       base::Bind(&EnumerateAttachedDevicesOnBlockingThread, devices),
    569       base::Bind(&PortableDeviceWatcherWin::OnDidEnumerateAttachedDevices,
    570                  weak_ptr_factory_.GetWeakPtr(), base::Owned(devices)));
    571 }
    572 
    573 void PortableDeviceWatcherWin::OnDidEnumerateAttachedDevices(
    574     const Devices* devices, const bool result) {
    575   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
    576   DCHECK(devices);
    577   if (!result)
    578     return;
    579   for (Devices::const_iterator device_iter = devices->begin();
    580        device_iter != devices->end(); ++device_iter) {
    581     OnDidHandleDeviceAttachEvent(&(*device_iter), result);
    582   }
    583 }
    584 
    585 void PortableDeviceWatcherWin::HandleDeviceAttachEvent(
    586     const string16& pnp_device_id) {
    587   DCHECK(media_task_runner_.get());
    588   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
    589   DeviceDetails* device_details = new DeviceDetails;
    590   base::PostTaskAndReplyWithResult(
    591       media_task_runner_,
    592       FROM_HERE,
    593       base::Bind(&HandleDeviceAttachedEventOnBlockingThread, pnp_device_id,
    594                  device_details),
    595       base::Bind(&PortableDeviceWatcherWin::OnDidHandleDeviceAttachEvent,
    596                  weak_ptr_factory_.GetWeakPtr(), base::Owned(device_details)));
    597 }
    598 
    599 void PortableDeviceWatcherWin::OnDidHandleDeviceAttachEvent(
    600     const DeviceDetails* device_details, const bool result) {
    601   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
    602   DCHECK(device_details);
    603   if (!result)
    604     return;
    605 
    606   const StorageObjects& storage_objects = device_details->storage_objects;
    607   const string16& name = device_details->name;
    608   const string16& location = device_details->location;
    609   DCHECK(!ContainsKey(device_map_, location));
    610   for (StorageObjects::const_iterator storage_iter = storage_objects.begin();
    611        storage_iter != storage_objects.end(); ++storage_iter) {
    612     const std::string& storage_id = storage_iter->object_persistent_id;
    613     DCHECK(!ContainsKey(storage_map_, storage_id));
    614 
    615     // Keep track of storage id and storage name to see how often we receive
    616     // empty values.
    617     MediaStorageUtil::RecordDeviceInfoHistogram(false, storage_id, name);
    618     if (storage_id.empty() || name.empty())
    619       return;
    620 
    621     // Device can have several data partitions. Therefore, add the
    622     // partition identifier to the storage name. E.g.: "Nexus 7 (s10001)"
    623     string16 storage_name(name + L" (" + storage_iter->object_temporary_id +
    624         L')');
    625     StorageInfo info(storage_id, storage_name, location,
    626                      string16(), string16(), string16(), 0);
    627     storage_map_[storage_id] = info;
    628     if (storage_notifications_) {
    629       info.set_location(GetStoragePathFromStorageId(storage_id));
    630       storage_notifications_->ProcessAttach(info);
    631     }
    632   }
    633   device_map_[location] = storage_objects;
    634 }
    635 
    636 void PortableDeviceWatcherWin::HandleDeviceDetachEvent(
    637     const string16& pnp_device_id) {
    638   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
    639   MTPDeviceMap::iterator device_iter = device_map_.find(pnp_device_id);
    640   if (device_iter == device_map_.end())
    641     return;
    642 
    643   const StorageObjects& storage_objects = device_iter->second;
    644   for (StorageObjects::const_iterator storage_object_iter =
    645        storage_objects.begin(); storage_object_iter != storage_objects.end();
    646        ++storage_object_iter) {
    647     std::string storage_id = storage_object_iter->object_persistent_id;
    648     MTPStorageMap::iterator storage_map_iter = storage_map_.find(storage_id);
    649     DCHECK(storage_map_iter != storage_map_.end());
    650     if (storage_notifications_) {
    651       storage_notifications_->ProcessDetach(
    652           storage_map_iter->second.device_id());
    653     }
    654     storage_map_.erase(storage_map_iter);
    655   }
    656   device_map_.erase(device_iter);
    657 }
    658 
    659 }  // namespace chrome
    660