ChromeOS: Implement MediaTransferProtocolManager observer.

chrome/browser/system_monitor/media_transfer_protocol_device_observer_chromeos.cc

+// Copyright (c) 2012 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.
+
+#include "chrome/browser/system_monitor/media_transfer_protocol_device_observer_chromeos.h"
+
+#include "base/metrics/histogram.h"
+#include "base/stl_util.h"
+#include "base/string_number_conversions.h"
+#include "base/string_split.h"
+#include "base/system_monitor/system_monitor.h"
+#include "base/utf_string_conversions.h"
+#include "chrome/browser/chromeos/mtp/media_transfer_protocol_manager.h"
+#include "chrome/browser/system_monitor/removable_device_constants.h"
+#include "chrome/browser/system_monitor/media_storage_util.h"
+#include "chromeos/dbus/mtp_storage_info.pb.h"
+
+namespace chromeos {
+namespace mtp {
+
+using chrome::MediaStorageUtil;
+
+namespace {
+
+// Device root path constant.
+const char kRootPath[] = "/";
+
+// Helper function to get an instance of MediaTransferProtocolManager.
+MediaTransferProtocolManager* GetMediaTransferProtocolManager() {
+  MediaTransferProtocolManager* mtp_dev_mgr =
+      MediaTransferProtocolManager::GetInstance();

[tbarzic, 2012/09/11 22:03:05]

I don't see the point of this function..
why not just use MediaTransferProtovolManager::GetInstance()?

[kmadhusu, 2012/09/11 23:30:53]

Removed the helper function and called GetInstance directly.

+  return mtp_dev_mgr;
+}
+
+// Helper function to get device id from storage name.
+std::string GetDeviceIdFromStorageName(const std::string& storage_name) {
+  std::string unique_id(chrome::kFSUniqueIdPrefix + storage_name);
+  return MediaStorageUtil::MakeDeviceId(MediaStorageUtil::MTP_OR_PTP,
+                                        unique_id);
+}
+
+// Helper function to get device label from storage information.
+string16 GetDeviceLabelFromStorageInfo(const MtpStorageInfo& storage_info) {
+  std::string device_label;
+  const std::string& vendor_name = storage_info.vendor();
+  device_label = vendor_name;
+
+  const std::string& product_name = storage_info.product();
+  if (!product_name.empty()) {
+    if (!device_label.empty())
+      device_label += chrome::kSpaceDelim;
+    device_label += product_name;
+  }
+  return UTF8ToUTF16(device_label);
+}
+
+// Helper function to get the device storage details such as device id, label
+// and location. On success and fills in |id|, |label| and |location|.
+void GetStorageInfo(const std::string& storage_name,
+                    std::string* id,
+                    string16* label,
+                    std::string* location) {
+  DCHECK(!storage_name.empty());
+  MediaTransferProtocolManager* mtp_dev_mgr = GetMediaTransferProtocolManager();

[tbarzic, 2012/09/11 22:03:05]

it's not obvious what |mtp_dev_mgr| means (especially dev part).
maybe mtp_manager ?

[kmadhusu, 2012/09/11 23:30:53]

Done.

+  DCHECK(mtp_dev_mgr);
+  const MtpStorageInfo* storage_info =
+      mtp_dev_mgr->GetStorageInfo(storage_name);
+
+  if (!storage_info)
+    return;
+
+  if (id)
+    *id = GetDeviceIdFromStorageName(storage_name);
+
+  if (label)
+    *label = GetDeviceLabelFromStorageInfo(*storage_info);
+
+  // Construct a dummy device path using the storage name. This is only used
+  // for registering device media file system.
+  // E.g.: /usb:2,2:12345
+  if (location)
+    *location = kRootPath + storage_name;
+}
+
+}  // namespace
+
+MediaTransferProtocolDeviceObserverCros::
+MediaTransferProtocolDeviceObserverCros()
+    : get_storage_info_func_(&GetStorageInfo) {
+  MediaTransferProtocolManager* mtp_dev_mgr = GetMediaTransferProtocolManager();
+  if (mtp_dev_mgr)
+    mtp_dev_mgr->AddObserver(this);
+  EnumerateStorages();
+}
+
+// This constructor is only used by unit tests.
+MediaTransferProtocolDeviceObserverCros::
+    MediaTransferProtocolDeviceObserverCros(
+        GetStorageInfoFunc get_storage_info_func)
+    : get_storage_info_func_(get_storage_info_func) {
+  // In unit tests, we don't have a media transfer protocol manager.
+  DCHECK(!GetMediaTransferProtocolManager());
+}
+
+MediaTransferProtocolDeviceObserverCros::
+~MediaTransferProtocolDeviceObserverCros() {
+  MediaTransferProtocolManager* mtp_dev_mgr = GetMediaTransferProtocolManager();
+  if (mtp_dev_mgr)
+    mtp_dev_mgr->RemoveObserver(this);
+}
+
+// MediaTransferProtocolManager::Observer override.
+void MediaTransferProtocolDeviceObserverCros::StorageChanged(
+    bool is_attached,
+    const std::string& storage_name) {
+  DCHECK(!storage_name.empty());
+
+  base::SystemMonitor* system_monitor = base::SystemMonitor::Get();
+  DCHECK(system_monitor);
+
+  // New storage is attached.
+  if (is_attached) {
+    std::string device_id;
+    string16 device_name;
+    std::string location;
+    get_storage_info_func_(storage_name, &device_id, &device_name, &location);
+
+    // Keep track of device id and device name to see how often we receive
+    // empty values.
+    UMA_HISTOGRAM_BOOLEAN("MediaDeviceNotification.MTPDeviceUUIDAvailable",
+                          !device_id.empty());
+    UMA_HISTOGRAM_BOOLEAN("MediaDeviceNotification.MTPDeviceNameAvailable",
+                          !device_name.empty());
+
+    if (device_id.empty() || device_name.empty())
+      return;
+
+    DCHECK(!ContainsKey(storage_map_, storage_name));
+    storage_map_[storage_name] = device_id;
+    system_monitor->ProcessRemovableStorageAttached(device_id, device_name,
+                                                    location);
+  } else {
+    // Existing storage is detached.
+    StorageNameAndIdMap::iterator it = storage_map_.find(storage_name);
+    if (it == storage_map_.end())
+      return;
+    system_monitor->ProcessRemovableStorageDetached(it->second);
+    storage_map_.erase(it);
+  }
+}
+
+void MediaTransferProtocolDeviceObserverCros::EnumerateStorages() {
+  typedef std::vector<std::string> StorageList;
+  MediaTransferProtocolManager* mtp_dev_mgr = GetMediaTransferProtocolManager();
+  DCHECK(mtp_dev_mgr);
+  StorageList storages = mtp_dev_mgr->GetStorages();
+  for (StorageList::const_iterator storage_iter = storages.begin();
+       storage_iter != storages.end(); ++storage_iter) {
+    StorageChanged(true, *storage_iter);
+  }
+}
+
+}  // namespace mtp
+}  // namespace chromeos