ChromeOS: Implement MediaTransferProtocolManager observer.

chrome/browser/chromeos/mtp/mtp_dev_manager_observer.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/chromeos/mtp/mtp_dev_manager_observer.h"
+
+#include "base/metrics/histogram.h"
+#include "base/stl_util.h"
+#include "base/string_number_conversions.h"
+#include "base/string_split.h"
+#include "base/stringprintf.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/media_gallery/media_gallery_constants.h"
+#include "chrome/browser/media_gallery/media_storage_util.h"
+
+namespace chromeos {
+namespace mtp{

[Lei Zhang, 2012/08/29 23:11:15]

nit: missing space

[kmadhusu, 2012/08/30 02:07:50]

Done.

+
+using base::SystemMonitor;

[Lei Zhang, 2012/08/29 23:11:15]

nit: You don't really need these. They're only used once.

[kmadhusu, 2012/08/30 02:07:50]

Done.

+using chrome::MediaStorageUtil;
+
+namespace {
+
+// Device root path constant.
+const char kRootPath[] = "/";
+
+// Helper function to get an instance of MediaTransferProtocolManager.
+MediaTransferProtocolManager* mtp_device_manager() {

[Lei Zhang, 2012/08/29 23:11:15]

nit: foo_function() usually means "this function is really cheap to call", and
FooFunction() means it is not cheap. So foo_function() calling BarFunction()
means it should be named FooFunction().

[kmadhusu, 2012/08/30 02:07:50]

Done.

+  MediaTransferProtocolManager* mtp_dev_mgr =
+      MediaTransferProtocolManager::GetInstance();
+  DCHECK(mtp_dev_mgr);
+  return mtp_dev_mgr;
+}
+
+// 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 GetDeviceInfo(const std::string& storage_name,
+                   std::string* id,
+                   string16* label,
+                   std::string* location) {
+  DCHECK(!storage_name.empty());
+  StorageInfo storage_info;
+  mtp_device_manager()->GetStorageInfo(storage_name, &storage_info);
+
+  if (id) {
+    std::string unique_id;

[Lei Zhang, 2012/08/29 23:11:15]

If you move this and the label block into their own helper functions, then
GetDeviceInfo will be only 15 lines and even easier to understand.

[kmadhusu, 2012/08/30 02:07:50]

Done.

+    const std::string& vendor_id = base::UintToString(storage_info.vendor_id());

[Lei Zhang, 2012/08/29 23:11:15]

UintToString return values should not be treated as references.

[kmadhusu, 2012/08/30 02:07:50]

Done.

+    const std::string& model_id = base::UintToString(storage_info.product_id());
+    const std::string& volume_id = storage_info.volume_identifier();
+    if (!vendor_id.empty() || !model_id.empty() || !volume_id.empty()) {
+      unique_id = base::StringPrintf("%s%s%s%s%s%s",
+                                     chrome::kVendorModelSerialPrefix,
+                                     vendor_id.c_str(),
+                                     chrome::kNonSpaceDelim,
+                                     model_id.c_str(),
+                                     chrome::kNonSpaceDelim,
+                                     volume_id.c_str());
+    } else {
+      unique_id = std::string(chrome::kFSUniqueIdPrefix) + storage_name;
+    }
+    *id = MediaStorageUtil::MakeDeviceId(MediaStorageUtil::MTP_OR_PTP,
+                                         unique_id);
+  }
+
+  if (label) {
+    std::string device_label;
+    const std::string& vendor_name = storage_info.vendor();
+    if (!vendor_name.empty())
+      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;
+    }
+    *label = UTF8ToUTF16(device_label);
+  }
+
+  // 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 = std::string(kRootPath) + storage_name;
+}
+
+}  // namespace
+
+MtpDevManagerObserver::MtpDevManagerObserver()
+    : get_storage_info_func_(&GetDeviceInfo) {

[Lei Zhang, 2012/08/29 23:11:15]

GetDeviceInfo -> GetStorageInfo
or
get_storage_info_func_ -> get_device_info_func_

[kmadhusu, 2012/08/30 02:07:50]

GetDeviceInfo => GetStorageInfo

+  mtp_device_manager()->AddObserver(this);
+  EnumerateStorages();
+}
+
+MtpDevManagerObserver::MtpDevManagerObserver(
+    GetStorageInfoFunc get_storage_info_func)
+    : get_storage_info_func_(get_storage_info_func) {
+}
+
+MtpDevManagerObserver::~MtpDevManagerObserver() {
+  if (mtp_device_manager())
+    mtp_device_manager()->RemoveObserver(this);
+}
+
+// MediaTransferProtocolManager::Observer override.
+void MtpDevManagerObserver::StorageChanged(bool is_attached,
+                                           const std::string& storage_name) {
+  DCHECK(!storage_name.empty());
+
+  SystemMonitor* system_monitor = 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.mtp_device_uuid_available",
+                           !device_id.empty());
+    UMA_HISTOGRAM_BOOLEAN("MediaDeviceNotification.mtp_device_name_available",
+                          !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 MtpDevManagerObserver::EnumerateStorages() {
+  typedef std::vector<std::string> StorageList;
+  StorageList storages = mtp_device_manager()->GetStorages();
+  for (StorageList::const_iterator storage_iter = storages.begin();
+       storage_iter != storages.end(); ++storage_iter) {
+    StorageChanged(true, *storage_iter);
+  }
+}
+
+}  // namespace mtp
+}  // namespace chromeos